fNtS CZt?#<2 C29827752 Czech Chemical Society I.M. Marci Spectroscopic Society Czech Radioecological Society in co-operation with the International Atomic Energy Agency

I

19th- 24th April 1998 Marianske Lazne - Jachymov Czech Republic

Organised on the occasion of the centenary of the discovery of and , and in honour of the late Prof. Jiff Stary 29-47 BOOKLET OF ABSTRACTS /f\/(SJ Czech Chemical Society I.M. Marci Spectroscopic Society Czech Radioecological Society in co-operation with the International Atomic Energy Agency

&m i

19th- 24th April 1998 Marianske Lazne - Jachymov Czech Republic

Organised on the occasion of the centenary of the discovery of radium and polonium, and in honour of the late Prof. Jifi Stary

BOOKLET OF ABSTRACTS TABLE OF CONTENTS

Opening plenary presentations A. A. Cigna Present status of radioecological research 24 ^?. Dybczynski A general approach to the construction of "very accurate" or "definitive" methods by , radiochemical NAA and the role of these methods in QA 26 ' /. Zvdra Gas phase chemistry studies of transactinoid elements and the relativistic effects 27 Chifang Chai Molecular activation analysis for chemical speciation studies 28 H. R. von Gunten Application of natural in environmental- and geosciences 29 P. De Regge, K. Burns, P.R. Danesi The IAEA programme and perspectives for environmental monitoring and preparation of reference materials 30

Chemistry of natural radionuclides, discovery of radium and polonium ,,Jachymov" historical session plenary presentations J. P. Adloff The laboratory notebooks of Pierre and Marie Curie and the discovery of polonium and radium 32 P. Benes, A. Zeman Jachymov (St. Joachimsthal) in the history of radioactivity 33 R. Mierzecki Marie Sklodowska-Curie (1867-1934) -A person and scientist 34 M. Vobecky Contribution of the industrial pitchblende chemical processing in Jachymov to the first isolation of radium 35 C. Jech 100 from the birth of prof. FrantiSek BShounek 36 Z. /. Kolar Emanations and "induced" radioactivity: From mystery to (mis)use 37 Poster presentations Pl-1 R. V. Bogdanov, Ju.F. Batrakov, D.E. Maslennikov, E. V. Puchkova, A.S.Sergeev On the valency of in aegirine and on behaviour of 234U and 238U at dissolving the mineral 40 Pl-2 R. V. Bogdanov, S.A. Gerasimov, S.A. Ozernaya, A.A. Pihlak, AS. Sergeev Organic substance as a collector of recoil atoms 234Th (234U) in black shales 41 Pl-3 S. V. Ioudintsev, B.I. Omelianenko Uranium and behaviour in endogenic processes. Geological observations and experimental research 42 PI-4 J. Rencova. V. Volf, MM. Jones, P.K. Singh Attempts to mobilize polonium-210 in the body 43 PI-5 B. Skwarzec Polonium, uranium and in the southern Baltic sea 44 Radionuclides in the environment, radioecology Verbal presentations H.W. Gdggeler - Invited lecture Use of short-lived radionuclides in aerosol chemistry 46 M. Wysocka, S. Chalupnik, A. Mielnikow, J. Lebecka, K. Skubacz Behaviour of radium isotopes released with brines and sediments from coal mines in Poland 47 A. Aksoy, W.S.A. Matter, Z.R. El-Naggar Radiometric analysis of selected phosphorite deposits of Northwestern Saudi Arabia 48 M. G. Germenchuk, O.M. Zhukova, E.D. Shagalova, I.I. Matveenko -131 distribution on the territory of the republic of Belarus during the first of the Chernobyl NPP catastrophe 49 Yu.K. Shchokin, M.G.Germentchuk, O.M.Zhukova, I.I. Matveenko Particularities of the Chernobyl's trace forming in Belarus and its dynamics during the posterior years 50 G. Lujaniene, V. Lujanas Cosmogenic radionuclide carriers in the atmosphere 51 N.B. Mikheev, S.A. Kulyukhin, M.Z. Kazakevich The role of isomorphism in the formation of mixed radioactive aerosols 52 O. M. Zhukova, I.I. Matveenko, Yu.M. Pokumejko, E.D. Shagalova Radioactive contamination of the Dnepr-Sozh river basin in Belarus after the accident at the Chernobyl NPP 53 J. Drissner, T. Klenk, E. Klemt, R. Miller, G. Zibold, M. Burger, A. Jakob Investigations on the -137 household of lake LUGANO, Switzerland 54 D. Knapinska-Skiba, R. Bojanowski Comparison of desorption of radiocaesium (Cs-137) from sea bottom sediment and near-shore region (the Baltic) 55 5. Chalupnik, A. Mielnikow, M. Wysocka, B. Michalik, J. Lebecka Investigations of the disequilibrium between Ra-226 and Po-210 in soils, river sediments and vegetation in the vicinity of coal mines 56 H. Nitsche - Invited lecture Actinides and the environment: What we know and what we need to know 57 V. Jedinakovd-Kfizovd Migration and retardation of long-lived radionuclides in geosphere 58 P. Misaelides, A. Godelitsas Interaction of actinides with natural microporous materials: A review 59 IS. Shaban, F. Macdsek, L. Mdtel Influence of humic acid on sorption of 137Cs, 85Sr, '"• 154Eu and 239Pu(IV) on Ca-montmorillonite 60 A. Braithwaite, L.N. Moyes, F.R. Livens, D. Bunker, C. Hughes, S. Richardson, J. T. Smith, J. Hilton Sorption kinetics of 238U and 237Np on glacial deposits 61 F. Briinjes, H. Barnewitz, G. Kirchner Diffusion and diffusion-convection experiments for studying the sorption of radionuclides on soils .... 62 A. Rigol, M. Vidal, G. Rauret, C.A. Shand, M. V. Cheshire Radiocaesium distribution between organic and mineral phases in organic soils 63 S.I. Zvaritch Dynamics of content of mobile 90Sr in soils in consequence of dissolution of Chernobyl fuel particles in natural conditions 64 S.L. Leinova, G.A. Sokolik, S.L. Kilchitskaya, T.G. Ivanovo, N.V. Zhukovich, l.M. Kimlenko Soil sorption complex influence on dynamics of 239|240Pu and 241Am mobile and fixed forms in different landscapes 65 T. Reich, H. Nitsche Application of X-ray absorption spectroscopy in radioecology 66 S. V. Ovsiannikova, G.A. Sokolik, S.L. Kiltchitskaya, E.A. Eismont, N. V. Zhukovich, l.M. Kimlenko 137 90 239 240 241 The role of pore soil solutions in redistribution of Cs, Sr, - pu and Am within soil-vegetative cover 67 G.A. Sokolik, S.L. Leinova, T.G. Ivanovo, V.V. Duksina, S.Ya. Rubinchik, V.V. Zakharenkov Biological accessibility of Chernobyl radionuclides and aspects of environmental rehabilitation 68 A. Baeza, J.M. Paniagua, M. Rufo, J. Barandica, A. Sterling A compartment model to evaluate the half-time of 90Sr and li7Cs in plants characteristic of a seminatural mediterranean ecosystem 69 M. Roig, M. Vidal, J. Tent, G. Rauret, M.C. Roca, V.R. Vallejo A soil- based model to predict radionuclide transfer in a soil- plant system 70 Y. Andres Microorganisms as potential vectors of the migration of radionuclides 71 P. Stepnowski, B. Skwarzec The bioaccumulation of 2l0Po and 210Pb in the Southern Baltic organisms 72 V. Koprda, M. Harangozo, L. Bohdcik, Z. Kassai Penetration of radionuclides across skin barriers of animal skin models in vitro 73 St.N. Kalmykov, Yu.A. Sapozhnikov, B.N. Goloubov Artificial radionuclides in oils from the underground nuclear test site (Perm' region, Russia) 74 Poster presentations P2-1 L. Albulescu, R. Gheorghe, D. Gruia, E. Dadulescu Estimation of 226Ra and 40K urinary level in case of people living in agricultural zone 76 P2-2 A. Baeza, L.M. del Rio, A. Jimenez, D. Cancio Influence of physico-chemical characteristics of freshwaters on their artificial radioactivity content 77 P2-3 H. Bern, E.M. Bern, M. Ostrowska Application of pulse decay discrimination liquid scintillation counting for indoor measurement 78 P2-A M. Bouby, I. Billard, J.MacCordick Complexation properties of the siderophore pyoverdine a towards different cations: \f*, UOj2+, Th4+ and others ; A comparative study 79 P2-5 Cheng-Hsien Hsieh, Chin-Wang Hhuang The investigation of uranium content in Hokuto hot spring water 80 P2-6 C. Cosma, L. Daraban, D. Ristoiu, L.Nagy Calibration of NaI(Tl) spectrometer for radiocesium volume-samples. Some results from Transylvania region 81 P2-7 Yu.P. Davydov, H.R. Westrich., I.G. Toropov, TV. Vasylevskaya, N.I. Voronik, V.I. Toropova Scientific basis for decontamination of soil contaminated as a result of the Chernobyl accident 82 P2-8 Yu.V. Dubina, L.N. Guskina, S.B. Kulich Study of fallouts of "non-volatile" radionuclides in southern Belarus after Chernobyl NPP accident 83

-5- P2-9 A. Durecova, F. £>urec Determination of ^'Ra and 228Ra in mineral and tap waters by using 3M's Empore™ radium RAD disks 84 P2-10 T. Elnimr.T. Sharshar, A. El-Abd Study on nuclear activities by the measurement of residual radioactivity 85 P2-11 V.N. Golosov, E. V. Kvasnikova, E.D. Stukin, D. Walling -210 and Caesium-137 as marks for studying the washoff and accumulation processes 86 P2-12 I.M. Fernandez Gomez, M. Prendes Alonso, N. Martinez Ricardo Levels of Ra-226 present in water sources of Havana City, Cuba 87 P2-13 S. Gozubuyiik, G. Yener, S.F. Erees Indoor radon concentrations in hospitals 88 P2-14 Guo-Chung Dong, Chin-Wang Huang An investigation of activity of radon containing in hot spring water in Taiwan 89 P2-15 E.J. Hanslik Prediction of impacts of Temelin NPP on hydrosphere 90 P2-16 K.H. Heise, R. Nicohi, S. Pompe, M. Buhner, H. Nitsche Melanoidins as model humic acids in radioecological research 91 P2-17 Z. Holgye, R. Filgas 238 239 240 241 242 244 Monitoring of releases of Pu, - pU) Am, Cm and Cm in gaseous effluents of V-3 and V-4 nuclear power plants at Dukovany in the Czech Republic in 1994, 1995, 1996 and 1997 92 P2-18 IV. Kazachevskiy, S.P. Pivovarov, V.P. Solodukhin, Kh. Sirajet, G.N. Chumikov, S.N. Lukashenko, A.B. Rukhin, T.A. Seredavina Radionuclides composition and paramagnetizm of soils of the SNTS 93 P2-19 S.L. Kiltchitskaya, G.A. Sokolik, T.G. Ivanovo, S.L. Leinova, I.M. Kimlenko, N.V. Zhukovich, V.V. Duksina The complex-forming and sorption processes of transuranium elements in the different soil types 94 P2-20 Z. Krejbichova Radioactivity of mineral waters in Bohemia 95 P2-21 A. V. Kudelsky, V.I. Pashkevich, S. V. Ovsiannikova, A.A. Petrovich Peculiarities of relationsip between radioactive caesium and stable in aquatic ecosystems 96 P2-22 E.V. Kvasnikova, E.D. Stukin, O.V. Glushko, V.N. Golosov, N.N. Ivanovo, A.V. Panin Caesium-137 behaviour in small agricultural catchment on the area of the Chernobyl contamination 97 P2-23 E.K. Legin, Yu.I. Trifonov, M.L. Khokhlov, D.N. Suglobov Phase behavior of Eu(III) in fulvic acid -Fe(III)-H2O system at pH 1-9 98 P2-24 G. Lujaniene, M. Bickel, V. Lujanas, B.I. Ogorodnikov, A. Mastauskas, R. Ladygiene, D. Jankunaite Chemical associations of radionuclides of Chernobyl origin 99 P2-25 B. Mack, A. Abraham, L. Baraniak, G. Bernhard, H. Nitsche Characterization of the redox behaviour of spruce lignin and humic acid 100 P2-26 /./. Matveenko, O.M. Zhukova, M.G. Germenchuk, E.D. Shagalova Investigation of radiation situation on the territory of Belarus on the base monitoring system 101 P2-27 J. W. Mietelski, K. Kozak, B. Was, M. Jasihska, JO. Krupa Plutonium isotopes concentration in the ground level air and rain samples from Krakow 102

-6- P2-28 K. Nakata, T. Fukuda, S. Nagasaki, S. Tanka, A. Suzuki, T. Tanaka, S. Muraoka Soiption of on oxide , 103 P2-29 U. Noseck Geochemical far-field processes in performance assessment for underground repositories 104 P2-30 S. V. Ovsiannikova, G.A. Sokolik, E.A. Eismont, S. Ya. Rubinchik Peculiarities of physico-chemical state of 137Cs in peat-bog soils 105 P2-31 O.G. Pol'skij, T.I. Paramonova, A.V. Panchenko Study of the concentration radionuclides in the environment of enterprises for decontamination of low and intermediate level radioactive wastes 106 P2-32 S. Pompe, M. Buhner, K.H. Heise, H. Nitsche Modified synthetic humic acids for the investigation of humic acid complexation behavior with uranyl ions 107 P2-33 V.B. Ribalka, I.N. Sirchenko, V.V. Serbinovich, S.I. Nikolenko Problems of investigations of microbial transformation of natural substances. Method of radiochemical matrix test in analysis of microbial changing of chelate properties of natural organic materials and behaviour of radionuclides in environment 108 P2-34 M. Rutsch, G. Geipel, G. Bernhard, H. Nitsche Interaction of uranium(VI) with arsenate in aqueous solution studied by Time-Resolved Laser-induced Fluorescence Spectroscopy (TRLFS) 109 P2-35 D. Sas, O. Navratil, P. Sladek Monitoring of natural factors in Czech speleocentres 110 P2-36 M.A. Shenber Activity concentrations of 7Be, 210Pb and 137Cs in surface air in Tripoli Ill P2-37 K. Schmeide, H. Zdnker, K.H. Heise, H. Nitsche Characterization of aquatic humic substances from bog water and their complexation behavior towards uranyl ions 112 P2-38 F. Schonhofer, M. Feigl-Heihs, K. Irlweck Natural radionuclides in drinking water in Austria 113 P2-39 Shih-Chang Lu, Fu-Yuan Huang, Chin-Wang Huang The investigation of radionuclides and morphology in hokutolite from Hokuto hot spring .... 114 P2-40 Kh. Sirajet, I. V. Kazachevskiy, G.I. Krasnov Problems of radon in Kazakstan 115 P2^U I.N. Sirchenko, V.V. Serbinovich, S.I. Nikolenko, I.P. Visekancev, I.J. Simonovskaya, V.B. Ribalka, G.I. Petelin The microbial danger from the 4-th unit of Chernobyl NPP 116 P2-42 P. Stepnowski, B. Skwarzec The distribution of polonium 2l0Po and radiolead 210Pb in the Baltic crustacean Saduria Entomon 117 P2^t3 V.V.Strelko New enterosorbents and sorptive fodder additives for radionuclides removal from the organism 118 P2-44 / Suksi, A. Lindberg, M. Siitari-Kauppi, E.S. Flitsiyan, P. Klobes, J. Goebbels, K.H. Hellmuth Uranium migration and fixation in a weathering profile in granitic rock 119 G. Szabo, J. Guczi, M. Del Nero, F. Gauthier-Lafaye Sorption-desorption of cesium on-from illite and illite coated with petroleum with reference to the Oklo natural fission reactors 120

-7- M. loader, R.A. Vasilache ^'Ra and 2l0Po intake in the population from Bucharest during the past five years 121 P2-47 H. Zanker, G. Hiittig, W. Richter, K. Schmeide, H. Nitsche Colloid characterization in a humic-rich environmental water with varying amounts of uranyl ions added 122 P2-48 H.A. El-Naggar, M.K. Shehata, E.M. Metwally Assessment of some industrial pollutants and their impact on the environment 123

Activation analysis and other radioanalytical methods Verbal presentations F. De Corte - Invited lecture Thirty years of NAA developments and applications at the THETIS reactor of the Institute for Nuclear Sciences, Gent 126 A.R. Byrne, L. Benedik Applications of neutron activation analysis in determination of natural and man-made radionuclides 127 D.A. Becker Accurate determination of trace elements in sediment CRMs by INAA 128 P. Robouch, G. Arana, J. Pauwels, S. Pomme IRMM certified reference materials and ko-NAA: An important role for the future 129 V. Iyengar, T.E. Gills Reference materials: Recent developments in health, food safety and environmental areas ..130 M. Bichler, C. Peltz, F. Sortino Comparing new techniques for the determination of minor and trace elements in volcanic gases by NAA 131 /. Salma, W. Maenhaut, E. Zemplen-Papp, J. Bobvos Investigation of size-fractionated urban aerosol and trace gases in Budapest by nuclear-related and other analytical techniques 132 V. Havrdnek, J. Kucera, J. Hordkovd, V. Vosecek Analysis of aerosols by two nuclear techniques 133 A.I. Pantelica, I.I. Georgescu, M.H.I. Oprica, CM. Borcia INAA and chemical analysis of water and sediments sampled in 1996 from the Romanian sector of the Danube river 134 A. Gaudry, X. Bertho, D. Picco, C. Fougeron Determination of elements in concrete of a nuclear accelerator to dismantle, by instrumental neutron activation analysis, 1CPMS and ICPAES 135 Y. Oura, H. Nakahara, K. Sueki, W. Sato, T. Tomizawa Completely non-destructive elemental analysis of bulky samples by PGA 136 T.L. Mobius, S. Mobius, E. Frenzel Determination of radon in water - A comparative study 137 D.A.W. Bossus, R. van Sluijs - Invited lecture Experience with NAA and radionuclides in an industrial laboratory 138 S.S. Ismail, R. lauster, G.P. Westphal, F. Grass Progress in short-time activation analysis 139 G.S. Sattarov, A.A. Kist Thermochromatography and activation analysis 140 B. Constantinescu, R. Bugoi Fast neutron activation analysis-FNAA using d( 13MeV>i-Be reaction at Bucharest cyclotron 141 A.A. Almohandis Petrochemical study of the Jabal Hamomah rocks using INAA and XRF methods, Khamis Mushyat Area, SW Saudi Arabia 142 S. Van Lierde, F. De Corte, D. Bossus, R. van Sluijs A re-examination of coincidence and gamma-peak doublet handling in KAYZERO-based NAA .... 143 J. Kucera, M. Marek, F. Tomdsek, J. Frana, Z. Hordk, L. Viereibl Calibration of the reactor neutron spectrum for the ko-NAA standardization using several approaches 144 M. Blaauw The well-type semiconductor detector harnessed 145 M. Korun Self-attenuation factors in gamma-ray spectrometry 146 S.J. Gelsema, M. Blaauw Coincidence summing corrections for natural radioactivity measurements using a Marinelli beaker detector setup 147 J. Vacik, S. Posta, V. Hnatowicz, J. Cervend Pulse-shape discrimination technique in radioanalytical methods 148 R. v. Hentig, T. Goldbrunner, G. Angloher, F. v. Feilitzsch Determination of radioactive trace elements in ultra low level detectors by means of neutron activation analysis 149 A. Faanhof-Invited lecture The measurement of natural radioactivity and the impact on humans 150 M.A. de Barros C. Menezes, C. de V. Schayer Sabino Thorium: Determination in Brazil 152 A. Mastauskas, R. Ladygiene, K. Gasiunas Determination of 222Rn concentrations in Lithuanian spa waters by liquid scintillation counting ... 153 J.M. Torres, M. Llaurado, G. Rauret Determination of '"Sr in environmental samples by microwave assisted digestion-chromatographic separation 154 Chien Chung Rapid measurement of radiation concentration by low-level air-borne spectrometry 155 Yu.M. Tsipenyuk, B.A. Chapyzhnikov, M. Fedoroff Fast radiochemical extraction of in photoactivation analysis of pure 156 E.A. Eissa, N.B. Rofail, L.S. Ashmawy, A.M. Hassan Neutron activation analysis of an Egyptian monazite ore sample 157 G. Yaprak, N.F. Qam Determination of toxic elements in tobacco by instrumental neutron activation analysis 158 N.I. Molla, S. Basunia, L. Zaman, S.M. Hossain, R. V. Miah, M. Rahman Determination of concentration in drinking water from tubewell 159 N.N. Nadirov, V.P. Solodukhin in organic fossils as determined by nuclear - physical methods of analysis 160 S. Rastikerdar 50 curie Am-Be neutron source in determining impurities in various materials 161 Poster presentations P3-1 J.L. Aguado, J.P. Bolivar, R. Garcia-Tenorio 226Ra determination in phosphogypsum by alpha-particle spectrometry 164

-9- P3-2 A. Aksoy, F.Z. Khiari, N. Al-Shayea Elemental analysis of selected soil and fertilizer samples from eastern Saudi Arabia 165 P3-3 T. Akyiiz, Q Bolcal, R. Kiicer, P. Saritepe, S. Akyiiz Neutron induced gamma-ray spectroscopic and X-ray fluorescence investigations of britholite veins of Basoren village (Turkey) 166 P3-4 T. Akyiiz, C. Bolcal, R. Kuger, E. Sener, A. Bafsari, M. Yildiz, Z. Kaplan, G. Dogan, S. Akyiiz Radioisotope X-ray fluorescence and neutron activation analyses of the trace element concentrations of the rainbow trout 167 P3-5 T. Akyiiz, A. Varinlioglu, A. Kose Gamma isotopic analysis of the coals and ashes from coal fired power plants of Turkey 168 P3-6 A.V.Andreev Analysis of multicomponent systems by fast neutron activation 169 P3-7 E.A. Arafa, F.H. Beshewa, A.I. Saleh Determination of iodine in drinking water 170 P3-8 S.A. Bakiev Methodological problems of activation analysis with radionuclide neutron sources 171 P3-9 V.I. Borisenkov, A.P. Chetverikov, G.A. Timofeev composition and burnup change of WER-1000 and WER-440 PWRs spent fuel along fuel element radius 172 P3-10 V.I. Borisenkov, Yu.S. Popov, G.A. Timofeev, A.P. Chetverikov Uranium-233 as alternative to the uranium-plutonium spike in determining of these elements in nuclear fuel by dilution mass spectrometry 173 P3-12 N. Cornejo Diaz, D. Perez Sanchez DETEFF- a Monte Carlo code for efficiency calculations in gamma-spectrometric measurements 174 P3-13 L Daraban, C. Cosma, J. Bacso, La. Daraban The analysis in sediments by activation with neutrons isotopic sources and X-ray fluorescence 175 P3-14 F.A. El-Amri, R.E. Damja, M.A.W. El-Gabroun, A.S. Musbahi, S.S. Ghiblawi, B.M. Abuhaggar, M.K. Jefayri Application of INAA in determination of trace elements in urinary calculi 176 P3-15 A.I. Ermakov, LA. Kashirin, A.V. Kovalev, V.B. Ribalka, A.I. Sobolev, V.A. Tikhomirov A new method of radiostrontium content determination using synthetic selective sorbents 177 P3-16 B. Gleisberg, S. Niese, M. Kohler Low-level radioactive measurements of radiochemical isolated from samples of contaminated areas and materials 178 P3-17 Tian Guoxin, Liang Junfu, Song Chongli, Mao Rongzhou The analysis of a-nuclides in HLLW in TRPO process 179 P3-18 R. Hinca, P. Uvdcik, V. Slugen, J. Lipka, J. Hascik, I. Toth, R. Grone, J. Degmovd Study of reactor pressure vessel steel specimens using gamma and Mossbauer spectroscopy 180 P3-19 V. Jirdnek, J. Janda Application of X-ray fluorescence analysis in paints verification 181

-10- P3-20 M. Kadirova, NM. Mukhamedshina, N. Jumaev, MM. Usmanova Instrumental neutron activation determination of impurities in technical and 182 P3-21 I.V. Kazachevskiy, G.N. Chumikov, S.N. Lukashenko, N.M. Berdinova, LA. Ryazanova, V.M. Muratova, L.N. Smirin, V.P. Solodukhin, G.I. Sychikov Complex radiochemical technique for the determination of Pu, Am and Sr-90 in soil samples of the SNTS 183 P3-22 R. Khelifi, Z. Idiri, A. Tchantchane, M. Seghir Prompt gamma neutron activation analysis of bulk samples 184 P3-23 F.Z. Khiari, A. Ahoy, M.N. AUHaddad Elemental analysis of selected Saudi Arabian coins using accelerator based slow neutrons 185 P3-24 V.P. Kolotov, V. V. Atrashkevich, N.N. Dogadkin Mapping of true coincidence effect value for voluminous sources measured withHPGE 186 P3-25 A. Kovalev, S. Kozakov, V. Ribalka, A. Ermakov, V. Serbinovich New method of determination of radiostrontium by using the synthetic selective sorbents (type VS-15) 187 P3-26 S.A. Makarov Precise determination of macroconcentration 188 P3-27 H. Moreno, I. Vioque, G. Manjôn, R. Garcia-Tenorio An easy and accurate method for 226 Ra determination in river waters by liquid scintillation counting 189 P3-28 N.M. Mukhamedshina Determination of impurities in and by INAA 190 P3-29 T. Nakanishi, M. Hirose, H. Fukuda, Y. Goto Determination of polonium-210 in phosphoric acid 191 P3-30 K.M. Ochsenkühn, NN. Papadopoulos, N.D. Antoniou, G.E. Hatzakis Short-time instrumental neutron activation analysis 192 P3-31 E. Panczyk, M. Ligeza, L. Walis Application of instrumental neutron activation analysis and X-ray fluorescence analysis to examination of the authenticity of art objects 193 P3-32 A.I. Pantelica, M.N. Salagean, E.A. Preoteasa, С Ionescu-Tirgoviste Trace elements in some new Romanian phytotherapeutic drugs investigated by neutron activation analysis 194 P3-33 MM Salagean, A.I. Pantelica, I.I. Brad, C.A. Rusu Neutron activation analysis of sea buck-thorn (Hippophae Rhamnoides) medicinal plant 195 P3-34 M.N. Salagean, A.I. Pantelica, I.I. Georgescu, M.I. Muntean Neutron activation analysis of some building materials 196 P3-35 Z. Sandor, S. Tölgyesi, I. Gresits, L. Jdrosi, J. Solymosi, M. Juhôsz Kâplânné Qualitative and quantitative analysis of medieval coins struck under the rule of Mathias by EDXRF 197 P3-36 I.A. Savushkin, A.M. Ragotner, A. V. Lukjanov, O.B. Gourko Gamma-spectrometric analysis of environmental samples of complex composition 198 P3-37 M. Samareh Shahpassand Investigation of trace elements in clay minerals by neutron activation analysis 199 P3-38 M. Samareh Shahpassand Neutron activation analysis of natural water applied to hydrogeology 200

-11- P3-39 M. Samareh Shahpassand, A. Molla (Fathemy)-Fathizadeh Determination of some trace elements in the serum of Thalasemia diseased using neutron activation analysis, PIXE and ICP 201 P3-40 /. Shtangeeva Neutron activation analysis as an useful instrument to solve some complicated questions of the environmental status 202 P3-41 B. Skwarzec Radiochemical methods for the determination of 55Fe, 63Ni, 210Po, 210Pb, 234U, 238 2Wt240 U and pu in the environmental samples 203 P3-42 LA. Smakhtin Estimation of the representative sample mass in neutron activation analysis 204 P3-43 V.V. Sokol'sky, V.P. Solodukhin, IV. Kazachevskiy The main direction of development of nuclear-physical methods of analysis for science and industry of Kazakstan 205 P3^t4 E.D. Stukin, M.D. Bondarkov, V.A. Zheltonozhsky X-ray spectrometry of transuranium radionuclides in the samples of the environment 206 P3-45 J.M. Torres, J. Tent, G. Rauret Rapid method for the determination of 90Sr in presence of l37Cs in contaminated samples 207 P3-46 G. Yaprak, C. Celikdag, N.F. Qam The determination of low level alpha activity in tobacco 208 P3-47 L.I. Zhuk, A.A. Kist Neutron activation analysis of human hair 209 P3-48 B.E. Dzevitskii, G.A. Skorobogatov Experimental technique for detection of induced gamma emission in transition Te(125m,2) ->Te(125m,l) + gamma (109,27keV) 210 P3-49 P.L. Ramos, J.R. Estevez Alvarez, A. Montero Alvarez, I. Pupo Gonzdles Preconcentration of trace metals in sea water and its determination using nuclear-related analytical techniques 211

Ionising radiation in science and technology Verbal presentation B. Bartonicek, V. Hndt, V. Placek - Invited lecture Radiation ageing of polymers 214 A.A. Abdel-Fattah, F.J.A. Said, M. El-Kelany, A.A. ElMiligy Ultraviolet and infrared spectral analysis of irradiated polypropylene films: Correlation and possible application for high - dose radiation dosimetry 215 El-SayedA. Hegazy, A.M.I. AH, H. Abdel-Rehim, H.G. Nowier, H.F. Aly Characterization and application of radiation grafted membranes in waste treatment 216 M. Ilavsky, M. Rerichovd, G. Mamytbekov, Z. Sedlakovd Samareh n of responsive hydrogels using irradiation 217 M. Radoiu, D. Martin, M. Dragusin, R. Moraru, C. Oproiu, I. Indreias, M. Toma, A. Manea Ionizing radiation in the field of hydrogels used for agriculture and medicine 218 A.P. Krasnopyorova The ionising radiation effect on physico - chemical properties of organosilicon oils 219

-12- A.S. Abdel Gawad, A.A. Abdel Fattah, Z.I. Ibrahim S. AH The use of gamma rays for the destruction of some organic ingredients present in water and wastewater. Part II 220 C. Jech Alpha recoil phenomena used for radiolabelling of surface layers of solids 221 M.V. Vladimirova Effect of polonium alpha-radiation on aqueous solutions (the history of French and Russian studies) 222 V.K. Mukhomorov On the mechanism of hydrated electrons regeneration in alkali aqueous solution after irradiation by light (wave length > 700nm) 223 A. Hategan, D. Hategan, V. V. Morariu, C. Oproiu, A. Popescu High energy electron beam inactivation of lactate dehydrogenase suspended in different aqueous media 224 M.I. Chipara, C. Oproiu, M. Dimonie, R. Mima, M. Badea, M. Vasile, M.D. Chipara, C. Mateescu, G. Brates, B. Negreanu, A. Tirlea, C. Secu Irradiation effects on polydicyclopentadiene 225 Poster presentations P4-1 D. Catana, A. Hategan, D. Martin, R. Moraru, V. V. Morariu, C. Petruc Influence of microwaves, high energy electron beam and gamma irradiation on the osmotic resistance of human erythrocyte membranes 228 P4-2 D. Catana, A. Hategan, V. V. Morariu, A. Niculescu, C. Oproiu, A. Popescu Possible Fricke dosimetry at low temperature 229 P4-3 A.M. Dessouki, H.F. Aly, H.H. Sokker The use of gamma radiation in wastewater treatment 230 P4-4 M. M. El-Dessouky, Abd-El-Elah A. El-Tawil Ivestigation of formation of (HI) ampicillin complex and its gamma radiolysis 231 P4-5 T. Elnimr, S.M. Abdel-Rahim Effect of gamma radiation on some elements in certain organs of albino rats 232 P4-6 A. Hategan, D. Martin, V. V. Morariu, A. Popescu, A. Niculescu, C. Oproiu, A. Margaritescu, V. Bestea Accelerated electron beam and microwave effects on the human erythrocyte membranes 233 P4-7 /. Indreias, D. Martin, C. Oproiu, V. Dima, S. Plamadeala, S. Marghitu, M. Toma, M. Radoiu, V. Bestea Microwave energy additional use to ionizing radiation for microorganisms sterilization 234 P4-8 D. Martin, M. Dragusin, M. Radoiu, C. Oproiu, R. Moraru, A. Manea, I. Indreias, M. Toma Ionizing radiation in the polyelectrolites technology 235 P4-9 C. Oproiu, V. Dima, D. Martin, S. Marghitu, A. Hategan, A.S. Popescu, M. Toma The influence of accelerated electrons on Escherichia Coli entherobacteria cytotoxic activity 236 P4-10 C.C. Ponta, R. Georgescu, IV. Moise, I.I. Georgescu Radiation and chemical treatment for preservation of cultural heritage 237 P4-11 V.M. Radchenko, A.G. Seleznev, R.R. Droznik, M.A. Ryabinin Study of -244 - Silicon interaction 238 P4-12 V. Zaichick, A. Dyatlov, A. Morozov Ionizing radiation for studying the age changes of human bone minerals 239

-13- Chemistry of actinide and trans-actinide elements Verbal presentations J.V. Kratz-Invited lecture, W. Paulus, E. Strub, S. Zauner, W. Brüchle, V. Pershina, M. Schädel, В. Schausten, J.L. Adams, K. E. Gregorich, D. С Hoffman, С. Laue, D.M. Lee, CA. McGrath, D.K. Shaughnessy, D.A. Strellis, E.R. Sylwester-Invited lecture Extraction of the fluoride-, chloride-, and bromide complexes of the elements Nb, Та, Pa, and 105 into aliphatic amines 242 A. Türler Gas phase chemistry of the transactinides 243 V.Ya. Lebedev, S.N. Timokhin, M. V. Vedeneev, A.B. Yakushev, I. Zvâra Chemical state of molybdenum, tungsten and element 106 in chlorinating gases 244 S. Taut, S. Hiibener, B. Eichler, K. Eberhardt, N. Trautmann, J.R. Peterson Thermochromatography of elemental 245 V.P. Domanov Tracer-scale chemistry of transition elements in the gas phase: Theoretical prerequisites and applications 246 /. May, RJ. Taylor, IS. Denniss, A.L. Wallwork Actinide complexation in the PUREX process 247 H. Capdevila, P. Vitorge Temperature and ionic strength influences on Actinide(VI)/(V) redox potentials for carbonate limiting complexes 248 L.L. Makarov, Ju.F. Batrakov The X-ray emission effects as a tool to study the light actinides 249 Ph. Moisy, L. Venault, S. Nikitenko, С Madie Redox reactions of U(IV) and Pu(IV) with H2O2 generated in nitric acid media by power ultrasound 250 RJ. Taylor, I. May, G.C. Brown The reduction of neptunium (VI) by formohydroxamic acid 251 A. Fedosseev, N. Budantseva, A. Bessonov, M. Grigoriev Complexe molybdates of U(VI) and Np(VI) 252 Poster presentations P5-1 A. V. Baluev Enthalpies of crystal lattices and standard enthalpies of formation of crystalline metal nitrates, acetates and haloacetates 254 P5-2 A. Bilewicz Solvent extraction of 4a and 4b metal chelate complexes. Model experiments for chemical studies on coordination number of element 104 255 P5-3 Han Bingbin, Wu Qiulin, Zhu Yongjun Study on the separation of U and Pu by non-reduction process 256 P5-4 W.C. Burnett, D. Reide Corbett, M. Schulz, E.P. Horwilz, R. Chiarizia, M. Dietz, A. Thakkar, M. Langer Preconcentration of actinide elements from soil and large volume water samples using extraction chromatography 257 P5-5 Liang Junfu Gamma-ray spectrometry in TRPO process used to treatment saline high-level liquid waste in China 258

-14- P5—6 Liang Junfu, Zhuang Yongneng, Xu Jingming, Zhu Yongjun Solvent extraction chemistry of in acidic organophosphorous extractants-acid system 259 P5-7 T. Mioduski Aquo ion stoichiometries of Radium(II), Actinides(II) and of some similar cations .... 260 P5-8 Ph. Moisy, L. Bion, F. Vaufrey, S. Méot-Reymond, E. Simoni, С. Madie + 16 Coordination of l/ in U(P2Wi706i)2 " anion 261 P5-9 LG. Molokanova, O.D. Maslov, S.Y. Tolmachyov, S.N. Dmitriev, M. V. Gustova Highly-sensitive method of determination of actinides in natural waters 262 P5-10 A.V. Sabelnikov, S.N. Dmitriev, O.D. Maslov, A.G. Belov Production and radiochemical isolation of 236Pu using the 237Np(y, n) reaction 263 P5-11 S. Nagasaki, S. Tsushima, S. Tanaka, A. Suzuki Complexes of uranyl and organic substances by molecular orbital calculation 264 P5-12 V.P. Nesterenko Synthesis and research of new (thorium-containing) ion-exchanging forms of the zeolites .... 265 P5-13 I.A. Tcharouchnikova, N.N. Krot Specific features of electron absorption spectra of some Np(IV) solid compounds 266 P5-14 С Maillard Studies about kinetic of Pu(VI) reduction by H2O2 and Pu(IV) peroxide formation 267

Separation methods, speciation Verbal presentations F. Macàsek - Invited lecture Analytical separation of radionuclides species with natural polyelectrolytes - proteins andhumic substances 270 Z. Kolarik, U. Müllich Separation of Am(III) and Eu(III) by selective extraction with N-donor extradants 271 S.A. Kulyukhin, N.B. Mikheev, A.N. Kamenskaya, I.A. Rumer Separation scheme for lanthanides and actinides based on the application of their lower oxidation states 272 A. Paulenovà, P. Rajec A study of colloid enhanced ultrafiltration of metals and radionuclides 273 P. Jurcek, V. Jedinâkovâ-Kfizovâ, P. Ivanova, E. Carballal Aguete Study of sorption and diffusion processes in natural bentonites 274 S.P. Mishra, V.K. Singh Efficient removal of and ions from aqueous solutions by hydrous eerie oxide - A radiotracer study 275 M.A.A. Asiani, S. Akyil Thorium (IV) adsorption on Ircilia Muscarum and its sorption kinetic 276 P. Rajec, J. Orechovska NIFSIL - A composite sorbent for caesium - Properties and application 277 Y. Allas, H. Tel, M. Eral Anion-exchange separation and determination of thorium and uranium in Eskisehir-Beylikahir ore in Turkey 278 A. Мой, F. Sebesta, J. John, I. Kadlecovâ Sorption of cobalt on hydrated dioxide 279 B. Salbu - Invited lecture Speciation techniques in radioecology 280

-15- C. Testa, S. Degetto, D. Desideri, F. Guerra, A.M. Meli, C. Roselli Determination and speciation of plutonium, , uranium, thorium, potassium and w Cs in a Venice canal sediment sample 281 B. Fourest, P. Tarapcik, R. Trskova, F. David, G. Lagarde, C. Lindecker, J.F. Le Du Solubility and transport measurements as tools for the speciation off-elements at tracer-scale amounts; Application to Eu and Th in phosphate media 282 /. Billard, M. Bouby, J.P. Brunette, G.J. Goetz-Grandmont, I. Rossini Behaviour of UO2 in high acid solutions (12 M): Characterization and complexation withHPBI 283 J. Mizera, P. Benes, E. Sebestovd Radiotracer study of the stability of complexes with humates and their size fractions 284 A.V. Legin, B.L. Seleznev, A.M. Rudnitskaya, Yu.G. Vlasov Multisensor system for determination of Iron(II), Iron(III) and Uranium(VI) in complex solutions 285 O. Courson, C. Le Naour, F. David Electrochemical behaviour of on mercury electrode in acetate buffer media 286 M. Kohlickovd, V. Jedinakova-Kfizova, M. Horejs Influence of technetium and speciation on their sorption on natural sorbents 287 H. Bruchertseifer Radiochemical trace and species analysis in nuclear safety research 288 Poster presentations P6-1 5. Akyil, M. Eral, M.A.A. Aslani Composite ion exchangers: Sorption characteristics of uranium and thorium in sulphate, nitrate and carbonate media 290 P6-2 A.M.I. AH, H.F.Aly Separation of Th and Zr from acid medium by 3-formyl-4hydroxy-N methyl 2 (H) quinoline 291 P6-3 G. A tun, E. Basfetin Adsorption of Ba on kaolinite, illite and montmorillonite at various ionic strengths .... 292 P6^ G. Atun, A. Kilislioglu The adsorption behavior of natural sand in contact with uranium contaminated sea water .... 293 P6-5 C. Chartroux, T. Rambusch, H. Stephan, K. Gloe, S. Ibach, M. Horn, F. Vogtle Solvent extraction studies of by spherical ligands incorporating aromatic subunits 294 P6-6 U.A. Chaudry Acid effect on the 99m Tc and " Mo mutual separation and transport across supported liquid membrane extraction system 295 P6-7 R. Chobola, A. Vincze, E. Erdos, J. Solymosi, P. Melt, L. Tbrok, T. Ranga, G. Volent Separation of Th-234 from Y-90 296 P6-8 Song Chongli, Wang Jianchen, Wang Qiuping Partitioning of from high-level liquid waste (HLLW) by dicyclohexano-18crown-6(DCH18C6) 297 P6-9 E. Danacikovd, J. John, A. Moll, F. Sebesta, E. W. Hooper Study of sorption properties of various samples of dioxide materials 298 P6-10 F. S. Erees, S. Akyil Removal of 226Ra from aqueous solutions using a cation exchange resin 299 P6-11 V.I. Golovanov, S.M. Kuznetsov Solubilisation of salts by di-(2-ethylhexyl)phosphate based on pH-titration data 300

-16- P6-12 A.A. Kopyrin, A.K. Piartman, V.A. Keskinov Separation of rare earthes by extraction with neutral organo- compounds in presence of complexones 301 P6—13 J. Lehto, K. Vaaramaa, T. Jaakkola Removal of natural radionuclides from drinking water by ion exchange 302 P6-14 L. Lima, S. Olivares, F. Martinez, J. Torres, D. De La Rosa, C. Sepulveda Use of immobilized tannin adsorbent for removal of Cr (VI) from water 303 P6-15 O. Navrdtil, Z. Skalican Extraction of selected bases by 0.1 M HC1 solutions of bis-l,2-dicarbollylcobaltate into chloroform 304 P6-16 S. Paldgyi Kinetics of transport extraction based on solvent sublation 305 P6-17 A.K. Piartman, A.A. Kopyrin, V.A. Keskinov, A.E. Berinsky Mathematical description and modelling of processes of separation and purification of lanthanides by solvent extraction and ion exchange 306 P6-18 Wu Qiulin, Han Bingbin, Zhu Yongjun Research on integration process of backend 307 P6-19 V.Remez Proximate analysis of concentration of radioactive ceasium in natural water 308 P6-20 Y.A. Sakharovskii, B.M. Andreev, E.P. Magomedhekov, Y.S. Park, M.B. Rosenkevich Working installation for purification of water flows by the method of the chemical isotope exchange of with water 309 P6-21 Z. Samczynski, R. Dybczynski Some examples of radiochemical separations using amphoteric ion exchange resins 310 P6-22 P. Slddek, O. Navrdtil, E. Herrmann Extraction of some metals with imidophosphorus reagents 311 P6-23 S. Smrckovd, F. Sebesta Study of mercury sorption on various insoluble ferro- and ferricyanides 312 P6-24 LA. Sobolev, S.A. Dmitryev, S. V. Stefanovsky, A.A. Kopyrin, A.K. Pyartman, V.A. Keskinov, M.A. Pleshkov. Separation of cesium-137 and strontium-90 in multicomponent systems by use of inorganic and polymer materials 313 P6-25 V.V. Strelko, V.V. Yatsenko, V.K. Mardanenko, V.G. Milgrant Fibrous sorbents for purification of complex composition solutions and milk from Cs radionuclides removal 314 P6-26 K. Uvirovd, F. Sebesta Comparison of cesium sorption on insoluble hexacyanoferrates(II) and (III) from acidic solutions 315 P6-27 P. Vanura The extraction of radioisotopes of alkaline earth metals and by crown ethers with dicarbollylcobaltate 316 P6—28 Feng Xiaogui, Liang Junfu, Song Chongli, Jiao Rongzhou Studies on the extraction behavior of technetium in Chinese TRPO process 317 P6-29 M. Yamaura, H.T. Matsuda Sequential separation of actinides and lanthanides by extraction chromatography 318 P6-30 V. Beckovd., P. Rulik Sequential extraction of radionuclides from aerosol filters from the ventilation stack of NPP Jaslovske Bohunice (Slovakia) 319

-17- P6-31 P.Benes, K.R. Czerwinski, J. Dolansky Effect of humic acid on the electrophoretic mobility of uranium (VI) in aqueous solutions 320 P6-32 M. Bouby, I. Billard, J. MacCordick Complexation of UO22+ by the Siderophore Mycobactin S 321 P6-33 J. van Doornmalen, J.T. van Eiteren, Z.I. Kolar, J.J. Kroon Kinetics of metal-ligand interactions in equilibrium systems using radiotracers 322 P6-34 V.l. Golovanov Critical micellation concentrations of polyvalent metal dialkylphosphates 323 P6-35 A. V. Harms, J.T. van Eiteren, H.Th. Wolterbeek, J.J.M. de Goeij Element speciation with a dual radiotracer technique: "Тс in spinach plants 324 P6-36 S.H. Pezzin, K.E. Collins, С Archundia, C.H. Collins Product speciation and aquation after the reaction of "CrfVI) with concentrated

HClandH2SO4 325 P6-37 E. V. Polyakov, Yu. V. Egorov, G.N. lives Physico-chemical modelling for sorption reactivity of true trace colloids 326 P6-38 E.V. Polyakov, G.N. lives, Yu.V. Egorov Interaction of Sr-90 with SC^2", HCO32" and CO32" ions in aqueous solutions of low salinity 327 P6-39 L. Skipperud, D.H. Oughton, B. Salbu The impact of speciation of Pu on the distribution coefficients in a soil - rainwater system 328 P6-40 S. Tsushima, S. Nagasaki, S. Tanaka, A. Suzuki Investigation of the interaction between organic compounds and uranyl ions by infrared and Raman spectroscopy 329 P6-41 С Hradecny, T. Tëthal and I.M. Yermolayev Isotope separation and containment of 24Na in light induced drift trap 330 Production and application of radionuclides Verbal presentations F.F. Knapp, Jr., A.L. Beets, S. Mirzadeh, С W. Alexander, R.L. Hobbs - Invited lecture Production of medical radioisotopes in the ORNL high flux isotope reactor (HFIR) for cancer treatment and arterial restenosis therapy after PTCA 332 J.J.M. de Goeij Alternative routes for supply of technetium-99m for diagnostic nuclear medicine 333 M. Fiser, P. Hanc, O. Lebeda, P. Hradilek, K. Kopicka Development and production of 8lRb/slmKr radionuclide generator in NPI 334 L. Koch, С Apostolidis, W. Janssens, R. Molinet, J. van Gee! Production of Ac-225 and application of the Bi-213 daughter in cancer therapy 335 O. Lebeda, M. Fiser, P. Hanc The production of 2llAt on the internal cyclotron beam and its separation from the target for nuclear medicine purposes 336 Z Slejkovec, J.T. van Eiteren, A.R. Byrne, J.J.M. de Goeij Neutron irradiation of organoarsenic compounds - A procedure for the preparation of [76As]-Arsenobetaine 337 S.N. Dmitriev, G.V. Buklanov, T.V. Shishkina, S.V. Shishkin, G.Ya. Starodub Production of high pure 97Tc for environmental research 338

-18-- V.M. Radchenko, B.M. Ândreychikov, G. Venke, V.D. Gavrilov, B.N. Korchuganov, R. Rider, M. A. Raybinin, T. Ekonomoy Curium-244 alpha-sources for space study 339 К. Sakamoto, H. Matsumura, К. Washiyama, H. Haba, Y. Miyamoto, S. Shibata, M. Furukawa, I. Fujiwara, H. Nagai, T. Kobayashi, K. Kobayashi Production of light nuclei from various targets with intermediate-energy bremsstrahlung 340 /. Fujiwara, H. Haba, H. Matsumura, Y. Miyamoto, K. Sakamoto, Y. Oura, S. Shibata, M. Furukawa Recoil studies of photonuclear reactions on 27A1, nalCu, natAg, "atTa, and l97Au at intermediate energies 341 N.G. Zaitseva, S.N. Dmitriev Radiochemical separation methods for a preparation of biomédical cyclotron radionuclides .. 342 Z.I. Kolar, H.J.M. van Dijk, T.G. Verbürg Radiotracer study of phosphate exchange between whey and casein micelles in cow's milk ... 343 D.Yu. Davydov, N.E. Prokshin, V.N. Zabrodsky, I.G. Toropov, Yu.P. Davydov Application of radioactive anions for determination of polynuclear complexes charge 344 A. Gosman, I. Hvozd'ovà, J.L. Martinez Nieto Measuring the difussion and sorption of trace elements and radionuclides in soils, clays andbentonites 345 Poster presentations P7-1 J. Ahl, S. Liukkonen Measurement of sodium-22 chloride tracer diffusion coefficient in the system 22 H2O + NaCl + MgCl2 at 25 °C : 348 P7-2 N.N. Andreychuk, A.Yu. Baranov, V.D. Gavrilov, L.S. Lebedeva, V.M. Radchenko, M.A. Ryabinin, I. V. Tselischev -252 fission fragments sources 349 P7-3 G. Atun, N. Bodur Isotope exchange of strontium and molybdate ions in strontium polymolybdates 350 P7-4 V.G. Balakhonov, V.A. Matyukha, N.P. Saltan, E.A. Filippov, A.N. Zhiganov Getting microsphere thorium dioxide 351 P7-5 Al. Cecal, S. Chisca, M. Palamaru Radiokinetic study on the nucleation, in agar and gelatin, of some crystals containing 55+59Fe3+ ions 352 P7-6 J. Doubsky, A. Lâznickovâ, M. Lâznicek, L. Leseticky Synthesis and biodistribution of some technetium - phosphonic acid complexes as potential bone scintigraphy agents 353 P7-7 D.0. Eriben, V. Bj0rnstad Synthesis ofradiolabelled organic compounds for use as water tracers in oil reservoirs 354 P7-8 5. V. Ermolaev, M. V. Lukianenko, LA. Smakhtin Extraction of rhenium-188 from and tungstates contaning tungsten-188 355 P7-9 M.A. Gonçalves, A.R.L. Nery, M. Yamaura, M.C.F.C. Felinto, R.L. Camilo, V.H. Cohen Unit operations mathematical simulation in a wMo production process for medical purposes 356 P7-10 A. Gosman, D. Housovâ, С. Jech, J. Konicek, L. Dolezalovd Nuclear-chemical methods of the hard tooth tissue abrasion study 357 P7-11 P. Hanc, M. Fiser, M. Honusek Preparation of radioactive ^Ti target 358

-19- P7-12 M. Imamura, T. Shibata, S. Shibata, T. Ohkubo, S. Satoh, N. Nogawa 252Cf spectrum-averaged cross section for the 63Cu(n,p)63Ni reaction 359 P7-13 E.A. Karelin, V.l. Karasev, V.M. Radchenko, VA. Makarenko, E.V. Shimbarev, M.A. Ryabinin, L.S. Lebedeva, V.D. Gavrilov, V.M. Vituytnev, NN. Andreychuk Neutron sources: Production and ways of technology improvement 360 P7-14 /. Kertész, S. Salvadori, G. Balboni, R. Guerrini, A. Borsodi, G. Tôth Tritiation of delta-receptor selective antagonist dipeptide ligands containing 2',6'- dimethyl-tyrosine 361 P7—15 A.P. Krasnopyorova Radioanalytical methods for estimation of salts solubility 362 P7-16 L.S. Lebedeva, A.Yu. Baranov, V.M. Radchenko, M.A. Ryabinin Americium-243 based sources 363 P7-17 F. Melichar, M. Kropâcek, P. Svihla, J. Stursa, J. Kucera, J. Lacman First experiences with production and quality control of 2-deoxy-2-[I8F]-fluoro- d-glucose in Nuclear Physics Institute, Academy of Sciences of Czech Republic 364 P7-18 A.E. Miroslavov, G.V. Sidorenko, DM Suglobov Chemistry and application prospects of technetium(I) carbonyl compounds 365 P7-19 V.P. Nesterenko, V.P. Glybin Synthesis and thermodynamic research of the process of the dehydration crystal monohydrate of the selenite of thorium 366 P7-20 B. Nock, T. Maina, I. Pirmeltis, M. Papadopoulos, С Tsoukalas, E. Chiotellis The potential role of intracerebral glutathione in the retention of a representative 99mTc SNS/S mixed ligand complex in mice brain 367 P7-21 V.M. Radchenko, A.G. Seleznev, M.A. Ryabinin, N.S. Kosulin Gamma-sources based on metallic americium-241 368 P7-22 I.A. SavushMn Technetium-99m production at centralized gel-generator on the basis of MOO3 369 P7-23 I.A. Savushkin, V.P. Koudriashov, O.B. Gourko, E.I. Ravkova Physical and chemical investigations on optimization of Zr-Mo gel-technology of 99mTc production 370 P7-24 S. Shibata, T. Shibata, M. Imamura, T. Ohkubo, S. Satoh, Y. Uwamino, N. Nogawa, M. Baba, S. Matsuyama, S. Iwasaki 63 63 Measurement of excitation function for Cu(n,p) Ni reaction up to En = 15 MeV 371 P7-25 S. Smrcek, L. Leseticky, M. ïâcek, P. Koutnik Biosynthesis of 35S-!abeled natural compounds using in vitro cultures of higher plants 372 P7-26 Cs. Tömböly, Zs. Laszlo, M. Spetea, A. Borsodi, G. Tôth [3H]Endomorphin II. A potent, selective, tritiated endogenous agonist for the |i-opiate receptor 373 P7-27 P. Viitanen Tracer techniques in studing ground water flow and it's dispersion in bedrock 374 P7-28 J.L. Vucina Effect of gentisic acid on stability of technetium - cold kits 375 P7-29 J. Stursa, J.Lacman, J. Kucera, M. dhàk, R. Jiran and M. Kfivânek Production of new radioisotopes on the isochronnous cyclotron U-120M 376

-20- Radiochemical problems in nuclear waste management Verbal presentations J.D. Navratil - Invited lecture Some recent developments in separation methods for the treatment of liquid radioactive wastes 378 T.A. Todd, K.N. Brewer, J.D. Law, D.J. Wood, R.S. Herbst, V.N. Romanovskiy, V.M. Esimantovskiy, I. V. Smirnov, V.A. Babain Development of a universal solvent for the decontamination of acidic liquid radioactive wastes 379 A.G. Chmielewski, M. Harasimowicz, G. Zakrzewska-Trznadel Membrane technologies for liquid radioactive waste treatment 380 H. Kodama Removal of iodide ion from simulated radioactive liquid waste 381 H. Ghafourian, M.R. Emami, A. Farazmand New method for separation of radium from Ramsar Area by MGF - 48 382 V.M. Efremenkov Activities of the IAEA in the area of radioactive waste management 383 F. Sebesta, J. John, A. Motl, K. Uvirova, S. Smrckova New generation of composite inorganic ion-exchangers with polyacrylonitrile binding matrix 384 D.P. Field, K. Harding, E. W. Hooper, F. Sebesta Caesium removal from fuel pond water using a composite ion exchanger containing nickel hexacyanoferrate 385 KM. Brewer, T.A. Todd, D.J. Wood, P.A. Tultock, F. Sebesta, J. John, A. Motl AMP-PAN column tests for the removal of 137Cs from actual and simulated INEEL high-activity wastes 386 F.M. Mekhail On the use of hexacyanocobaltates in the separation of caesium from radioactive waste solutions 387 E. Wieland, J. Tits, P. Spieler, J.P. Dobler Immobilisation of strontium, nickel and iodide by a sulphate-resisting portland cement 388 N.E. Cherniavskaya, A. V. Ochkin, S. V. Chizhevskaya, S. V. Stefanovsky Perovskite as a matrix for incorporation of long-lived radionuclides 389 Poster presentations P8-1 N.L. Arancibia, R.V. Bogdanov, V.B. Glushkova, R.A. Kuznetsov, V.A. Krshishanovskaya, T.I. Panova, A.S. Sergeev Granite and apatite based ceramics as matrix materials to immobilise the radioactive wastes 392 P8-2 B. Bilgin, G. Atun, G. Keceli Adsorption of Sron illite 393 P8-3 Al. Cecal, V. Rudic, A. Gulea, I. Palamaru, D. Humelnicu, V. V. Salaru, K. Popa Removal of uranyl ions from residual waters using some algae types 394 P8-4 S.K. Durrani, N.A. Chughtai, J. Akhtar Borosilicate high silicious zeotype materials used for immobilisation of caesium from radioactive aqueous waste solution 395 P8-5 I.M. El-Naggar, E.S. Zakaria, MM. Abou-Mesalam, H.F. Aly Removal of some radioactive nuclides by in-situ precipitation with ion exchange materials 396

-21- P8-6 E. Forster, K.H. Heise, H. Nitsche Anodic oxidation of the carbon-14 labeled organic waste 397 P8-7 N. Hafez, M.S. Sayed Physico-chemical studies involving incorporation of radioactive and industrial wastes 398 P8-8 N. Hafez, M.S. Sayed Quantitative determination of thorium, uranium and some fission products found in industrial and radioactive waste 399 P8-9 T. Iwaida, S. Nagasaki, S. Tanaka Dissolution, sorption, and colloid generation in cementitious material-water system 400 P8-10 G. Kuznetsov, A. Pushkov, L. Shklyar Laboratory radiochemical setup of centrifugal extractors 401 P8-11 M. Mahramanlioglu, A. Kilislioglu, M. Tungay Sorption behaviour of uranium on activated bentonites from aqueous solutions 402 P8-12 M. Mahramanlioglu, I. Kizilcikli, I.Ozlem Biger, M. Tunqay The adsorption of uranium from aqueous solutions on activated used tires 403 P8-13 S.P. Mishra, D. Tiwary Ion exchanger in radioactive waste management. Part XII: Removal of and strontium ions from aqueous solutions by hydrous ferric oxide 404 P8-14 A.V. Ochkin, S.V. Chizhevskaya, S.V. Stefanovsky, S.N. Dmitriev, L.G. Molokanova Zirconolite as a host phase for uranium incorporation 405 P8-15 A.I. Orlova, Yu.F. Volkov, V.I. Petkov, LA. Kulikov, V.N. Zyryanov, O. V. Egorkova, D. V. Kemenov Concentrating cesium, stroncium, REE and actinides into zirconium-phosphate ceramic matrix attached to nuclear waste forms 406 P8-16 A.V. Panchenko, LA. Kashirin Express-method for decontamination by use of mono-izo-octyl-methyl-phosphonic acid compounds 407 P8-17 LA. Sobolev, S.V. Stefanovsky, S.V. loudintsev, B.I. Omelianenko, B.S. Nikonov Study of ceramics for actinide waste fixation 408 P8-18 L. Stoica, D. Filip, A. Razvan Decontamination of aqueous systems containing M6Ra(n) by coprecipitation -flotation and solid-liquid adsorption 409 P8-19 I.G. Toropov, V.N. Zabrodsky, N.E. Prokshin, D.Yu. Davydov, V.M. Efremenkov Development of combined methods for liquid radioactive waste treatment on the basis of data on radionuclide forms in solution 410 P8-20 V.T. Vacariu, P.D. Georgescu, R. Mathe Removal of 226Ra from liquid and solid wastes of uranium and fertilizer industry in Romania 411 P8-21 J. Vacik, V. Hnatowicz, J. Cervena, I. Peka Molten fluoride salts incorporation in pristine and ion-modified carbon allotropes and metallic foils 412 P8-22 A. Kladov Nuclear reactions in the cavitation bubble 413

Author index 415

-22- Opening session

PLENARY PRESENTATIONS

-23- CZ9827753 PRESENT STATUS OF RADIOECOLOGICAL RESEARCH

Arrigo A. Cigna Union Internationale de Radioecologie

Radioecology can be defined as the science concerned with the interactions between radionuclides and the environment and with their effects on man and biotic communities. Hence, it is a special field of ecology focusing on radionuclides as the object and the main tool of research to understand environmental processes. On account of the great sensitivity of the radioactivity measurements, minute amounts of radionuclides could be easily identified and measured in different environmental compartments without any slight interference with the metabolisms of living organisms. Many processes and phenomena could then be detected and studied. Ecology took advantage from such studies because tracer radionuclides were instrumental in understanding many ecological processes. During the" fallout period" a great number of laboratories were active all over the world in connection with nuclear research centres, nuclear power plants and other institutions. After the moratorium of the atmospheric nuclear bomb testing in 1963 the decrease below the detection limits of many of the artificial radionuclides prresent in the environment, together with the important reduction of radioactive discharges from nuclear plants, led to lesser attention to the measurements of environmental radioactivity together with a decrease of competent laboratories During the nuclear weapons fallout period the behaviour of most important radionuclides y 13 (typically: "Sr , ^Cs, 239,240pu) jn most critical pathways were studied; after the Chernobyl accident studies were extended to natural and semi-natural ecosystems and other less common radionuclides. A further step should be the study of the mechanisms regulating the behaviour of radionuclides in different compartments of the environment. The interest to extend the knowledge in this field is not a purely academic one because such an extended knowledge could be essential to improve the level of radiation protection by actively enhancing some convenient environmental process and not simply by relying passively on the natural transfer pathways. Semi-natural and natural ecosystems are of special interest in the context of environmental radioactivity. Such an interest occurred during the sixties when it appeared that lJ('Sr along the foodchain lichen-reindeer-man, contaminated man. It showed at the same time the importance of artificial radionuclides as a tool for tracing and understanding nutrient turnover in ecosystems. Semi-natural ecosystems may hide other critical pathways for radionuclides transfer to man and may also act as temporary sinks or long-term sources for radionuclides deposited from the atmosphere. Further research and modelling is therefore required. In principle the implementation of radiation protection criteria for man, which are based on the protection of a single individual, assures the protection of organisms other than man since it is requested the protection of a population only. Nevertheless in some special case, as in the deep- sea environment, such radiation protection criteria could not avoid a detrimental effect in plants and animals populations Therefore the problem of the protection of organisms other than man has to be investigated In case of serious contamination scenarios there is a need of realistic evaluations of the effectiveness of the countermeasures that could be undertaken In particular studies on biogeochemical transfer mechanisms which control the cycling of radionuclides should be developed Research presently underway has identified key issues characterizing the differences between

-24- natural and agricultural ecosystems, like bioavailabihties and residence half-tunes of radionuclides in the relevant compartments With reference to the future developments of the nuclear industry, some attention should be paid to the operation and the releases of, e.g., intrinsecally safe reactors and fusion plants Some radionuclides involved in these plants have not been studied in the classic radioecological investigations concerning the fission power plants and, therefore, deserve a special attention Besides those potential new-type sources, also the decontamination and possible site restoration of military installations have to be considered

-25- CZ9827754 A GENERAL APPROACH TO THE CONSTRUCTION OF "VERY ACCURATE" OR "DEFINITIVE" METHODS BY RADIOCHEMICAL NAA AND THE ROLE OF THESE METHODS IN QA

Rajmund Dybczyoski Department of Analytical Chemistry, Institute of Nuclear Chemistry and Technology, 03-195 Warszawa, uLDorodna 16

Constant progress in instrumentation and methodology of inorganic trace analysis is not always paralelled by improvement in reliability of analytical results. Such conclusion can be drawn from the scrutiny of outcomes of numerous interlaboratory comparisons as well as problems in assigning certified values for low levels of some "difficult elements" in new reference materials. The reasons why gross errors in trace analysis occur so frequently are numerous. The analyte can be lost e.g. by incomplete dissolution, volatility, adsorption, incomplete transformation into the desired chemical form etc. On the other hand the analyte can be added to the sample from sampling devices, laboratory glassware, acids, solvents, reagents, ambient air. In the step of quantitative determination, due to various types of interferences, the dependence of intensity of the analytical signal upon analyte concentration in the real sample may often be different than the analogous dependence for the elemental standard Most of these problems can be overcome by using neutron activation analysis, as a method that is essentially free from blank, in combination with carefully designed and comprehensively tested radiochemical separation scheme followed by measurement of the radionuclide in question by high resolution y-ray spectrometry. Our approach to construction of "very accurate" methods for the determination of selected trace elements in biological materials by RNAA is based on an assumption that: 1. The radionuclide in question should be selectively and quantitatively isolated from the irradiated sample by a suitable radiochemical scheme, optimized with respect to this particular radionuclide, yielding finally the analyte in the state of high radiochemical purity what assures interference-free measurement by y-ray spectrometry 2 The radiochemical scheme should be based on ion exchange and/or extraction column chromatography resulting in an easy automatic repetition of an elementary act of distribution of the analyte and accompanying radionuclides between stationary and mobile phases 3 The method should have some intrinsic mechanisms incorporated into the procedure preventing any possibility of making gross errors. Based on these general assumptions several more specific rules for devising of "very accurate" methods were formulated and applied when elaborating our methods for the determination of copper, cobalt, nickel, cadmium , molybdenum and uranium in biological materials [1] The significance of such methods for Quality Assurance is pointed out and illustrated by their use in the certification campaign of the new Polish biological CRMs based on tobacco

REFERENCES 1 R.Dybczynski in: ..Harmonization of health related environmental measurements using nuclear and isotopic techniques", IAEA, Vienna, 1997, pp 199-211

-26- CZ9827755

GAS PHASE CHEMISTRY STUDIES OF TRANSACTINOID ELEMENTS AND THE RELATIVISTIC EFFECTS

Ivo Zvara h'lerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980 Dubna, Russian Federation

Gas phase chemistry techniques, being generally much faster than solution chemistry procedures, have played a major role in experimental studies of the transactinoid elements (atomic number greater than 103), which possess half-lives not longer than a minute. The Dubna group have mostly worked with spontaneously fissioning nuclides and used gas-solid thermochromatography, when a longitudinal negative temperature gradient is imposed on an open column Then an inner chromatogram is obtained, and the material of the column (fused silica) serves as a solid state track detector of fission fragments. The PSI, Villigen (Switzerland) and LBL, Berkeley (USA) groups have preferred the isothermal chromatography. They have measured (at the exit of the column, using spectrometnc detectors) the alpha-active atoms which had not decayed during the retention time. Advantages of the two complementary methods are discussed. To date, only elements 104 to 106 have been chemically identified, and their halides and/or oxohalides have been studied. A review of the results is presented For the near future, there are good prospects of exploring volatile, acid-like compounds of elements 106 and 107, as well as oxides of elements 107 and 108. The most challenging problem in the chemistry of transactinoids is the so called relativistic effects in their properties. The relativistic velocities of all the .V|,2 and p^n atomic electrons must affect the binding energy and shape of their orbitals. Hence, the properties of the heaviest elements might show deviations from the trends observed for lighter members of the appropriate subgroups in the Mendeleev System. To conclusively identify the relativistic effects, both the results of sophisticated relativistic calculations of atoms and molecules (ions) and the experimental data obtained with single atoms (molecules, ions) must be interpreted in terms of expected macroscopic characteristics of the species involved (e.g., boiling point, stability of complexes, etc.) and then confronted with each other. The problem is analyzed using the volatility of (oxo)chlorides of the transition metals of groups IV to VI in their higher oxidation states as an example. When searching this way for the relativistic effects, the gas phase chemistry approach has some principal advantages: the molecules of the (oxo)halides are of nearly spherical shape and keep their identity when forming condensed phases or adsorbing on nonactive surfaces, as they mostly interact due to dispersion forces. From the the point of view of the calculational chemistry, the latter situation seems to be easier than the situation of complex ions (in a dynamic equilibrium) in quite concentrated solutions of acids and/or complexing agents, which one encounters in most of the solution chemistry experiments performed to date.

-27- CZ9827756

MOLECULAR ACTIVATION ANALYSIS FOR CHEMICAL SPECIATION STUDIES

Chifang Chai Institute of High Energy Physics, Chinese Academy of Sciences, P.O.Box 2732, Beijing 100080, China

The term of Molecular Activation Analysis (MAA) refers to an activation analysis method that is able to provide information about the chemical species of elements in system of interests, though its definition has remained to be assigned. Its development is strongly stimulated by the urgent need to know the chemical species of elements, because the total concentrations are often without any meaning when assessing health or environmental risks of trace elements. In practice, the MAA is a combination of conventional instrumental or radiochemical activation analysis and physical, chemical or biochemical separation techniques. The MAA is able to play a particular role in speciation studies. However, the critical point in the MAA is that it is not permitted to change the primitive chemical species of elements ir. systems, or the change has to be under control; in the meantime it is not allowed to form the "new artifact" originally not present in systems. Some practical examples of MAA for chemical species research performed recently in our laboratory will be presented as follows:

I.Chemical species of group elements in sediment; 2. Chemical species of iodine in marine algae; 3.Chemical species of mercury in human tissues, 4.Chemical species of in corn; 5 Chemical species of rare earth elements in natural plant, etc

The merits and limitations of MAA will be described as well

This work is financially supported hy National Natural Science Foundation of China (NSh'C. Contract No. 19392100).

-28- CZ9827757

APPLICATIONS OF NATURAL RADIONUCLIDES IN ENVIRONMENTAL- AND GEOSCIENCES

H. R. von Gunteii Labor fur Radio- mid Umweltchemie Paul Scherrer Institut (PSI) CH-5323 VilligenPSl, Switzerland

Nuclides of the natural series are well for investigations of environmental and geochemical processes. Examples of applications of these nuclides will be outlined: • A 21lPb (i.e., epiphaniometer) is used as continuos monitor for environmental aerosol at very low concentrations. • Radioactive disequilibria in the uranium decay series give insight into geochemical processes. • Dated (210Pb) lake sediments and glacier ice cores allow, together with the analysis of cations and anions a reconstruction of past environmental conditions. • In the context of the 100th anniversary, the geochemical behaviour of radium in the water column and in sediments of Lake Zurich will be discussed.

-29- CZ9827758

THE IAEA PROGRAMME AND PERSPECTIVES FOR ENVIRONMENTAL RADIONUCLIDE MONITORING AND PREPARATION OF REFERENCE MATERIALS

P. De Regge, K. Burns, P.R. Danesi International Atomic Energy Agency, SeiberxJorfLaboratories, P.O. Box 100, Wagramerstrasse 5, A-1400 Wien Austria

For more than thirty years, the laboratories of the International Atomic Energy Agency have been involved in the monitoring of environmental radioactivity and in the worid-wide provision of reference materials for radionuclides in environmental matrices. Site specific studies in areas contaminated either by nuclear accidents (e.g. Chernobyl) or nuclear tests (e.g. Mururoa, Marshall Islands) revealed that a significant part of the radioactivity released can be carried by hot particles. The occurrence of hot particles in selected sites and their morphological, structural, chemical and radiochemical characteristics have to be better investigated in order to identify possible correlations with the contaminating event and to assess the associated radiological risks Research on radionuclides in the environment will also be extended to the measurement and compilation of data on the contaminants introduced by non- nuclear industrial activities and agrochemical treatments. In particular the bioavailability of radionuclides of natural and anthropogenic origin will be examined. Specific methods for this purpose will be developed in the framework of the IAEA's Co-ordinated Research Programmes. In response to the world-wide trend towards increased reliability, comparability and traceability of chemical and radiochemical measurements, the IAEA will revise, develop and document a set of reference analytical procedures for naturally occurring radionuclides, which will supplement the current revision of procedures for anthropogenic radionuclides. The IAEA will enhance its support provided to the laboratories in the Member States for the implementation of a quality system and to achieve traceability of their radiometric measurements. As a component of this action, several IAEA intercomparison materials for radionuclides in biological and environmental matrices will be upgraded to achieve traceability of their property values to the international system of units Furthermore the IAEA will continue to provide training and maintain comparibility and reliability of environmental radiochemical measurements by organising proficiency tests and interlaboratory comparisons. These tests and exercises will also be used by the IAEA to monitor and evaluate the capability and preparedness of its ALMERA (Analytical Laboratories for Measuring Environmental Radioactivity) Network to provide timely and reliable radionuclide measurements in an international framework when so required on a global or regional basis

-30- Topic 1 CHEMISTRY OF NATURAL RADIONUCLIDES, DISCOVERY OF RADIUM AND POLONIUM ,,Jachymov,, historical session plenary presentations

-31- THE LABORATORY NOTEBOOKS OF PIERRE AND MARIE CURIE AND THE DISCOVERY OF POLONIUM AND RADIUM

J. P. Adloff 63 Rue Saint-Urbain, F-67100 Strasbourg, FRANCE

One hundred years ago Pierre and Marie Cune discovered the elements polonium and radium in a few hundred grams of Joachimsthal (Jachymov) pitchblende. This unique event which announced the dawn of radiochemistry is reconstituted by the light of Pierre and Mane Curie's laboratory dianes, their three communications at the Academy of Sciences and the scientific knowledge at the end of the 19"1 century.

-32- JACHYMOV (ST. JOACHIMSTHAL) IN THE HISTORY OF RADIOACTIVITY

P. BeneS and A. Zeman Department of Nuclear Chemistry, Czech Technical University, Bfehovd " 115 19 Praha I, Czech Republic

The role of Jachymov in the history of radioactivity will be reviewed from the several points of view. First, a brief account of the ore mining in Jachymov will be given with emphasis on the production of silver and uranium dyes. Then the role of Jachymov in the discovery of polonium and radium and in the early production of radium will be discussed. Early measurements of natural radioactivity in Jachymov area as well as radiotherapeutical use of radioactive waters in the town will be described. Jachymov was among the sites where the adverse effects of radioactivity on the human health were first observed (so called Joachimsthal miners' disease). Ore mining and treatment caused extensive contamination of Jachymov area with natural radionuclides. The presentation will finish with a short overwiew of the contamination and of the remedial actions.

-33- MARIE SKtODOWSKA-CURIE (1867-1934) — A PERSON AND SCIENTIST

R. Mierzecki ul. J. Bytnara 23 m. 19, Warszawa, Poland

Marie Sklodowska was born in 1867 in Warsaw, Freta street 16. At that time there was a known girl-pension (school) and her mother was its superior. To-day this house is a seat of the Polish Chemical Society and of the Marie Sklodowska-Curie Museum. Her father was a teacher of physics in a state Russian gymnasium, as at that time the teaching in Polish was forbidden in Warsaw. The Sklodowski's family belonged thus to the social class of Polish ,,inteligencja", for which the development of national welfare and culture was more important than a personal success. After completing her secondary education in a Russian gymnasium Mane could not enter either the Russian Imperial University in Warsaw or the Polish universities in Lvov and Cracov, as women were not accepted there. To have a possibility to study in Pans she had to wait for six years gathering the needed money as a private instructress, helping at that time her older sister Bronislawa to finish in Paris her medical studies. At that time Marie is also a student of the clandestine Polish 'Flying University' and learned the chemical analysis methods in the laboratory of the Museum for Industry and Agriculture in Warsaw. With a great consequence in his private life and in scientific research she persuaded her aim. In 1891 with the help of her sister she enters Sorbona University in Paris, in 1893 she becomes a licentiate of physical, and next of mathematical science. In 1894 she meets for the first time Pierre Curie, whom she decided to marry next year. It is after her unsuccessful attempts to get a place of assistant at Cracov University. Pierre convinced her that in France she will have more possibilities to work than in Poland. All her life Marie tried to help to Polish science. Thus the first new element discovered by Curies was named in honour of Poland that did not exist at that time on the political carts. Information about their works Marie send to Polish magazines as soon as possible. From Pans she supervised the works of Polish laboratories dealing with radioactivity and made efforts to supply them with radioactive matenals. In the time of the World War I she left her scientific research and organised mobile Roentgen laboratories to help the solders wounded on the battle-field. However, in spite of great contributions to the French science and population as a woman and foreigner she had to be in anguish several times. In 1995 she was honoured, however, by the French government as the first woman buried in Pantheon as a tribute to her own merits

-34- CONTRIBUTION OF THE INDUSTRIAL PITCHBLENDE CHEMICAL PROCESSING IN JACHYMOV TO THE FIRST ISOLATION OF RADIUM

Miloslav Vobecky Academy of Science of the Czech Republic Institute of Analytical Chemistry, Prague

The uranium ore chemical processing plant in Jachymov (St. Joachimstal) started the industrial production of uranium yellow (sodium diuranate) in 1853. This technology was developed by the talented metalurgical chemist Adolf Patera 1>2t3. The insoluble residue from uranium leaching was enriched by radium 224Ra. During more than forty years before discovery of radioactivity the worthless waste was accumulated in this uranium factory. This waste as radium preconcentrate was in a suitable chemical form for subsequent separation of radium. The occurence of that material significantly facilitated the laboratory-scale separation and isolation of the first pure weighable amount of radium necessary to prove existence of a new , discovered in 1898 by M. and P. Curie and G. Bemont4.

1. Patera A., Sitzungsberichte der kais. Akademie der Wissenschaften, Math.-Naturwiss. Classe, 11(1853)842-844. 2. Patera A., J. prakt. Chem., 61 (1854) 397-398. 3 Vysoky E., Dinglers Polytech. I, 181 (1866) 448-455. 4. Curie P., Curie M, Bemont G,C R. Acad. Sci. Paris, 127(1898) 1215-1217

-35- 100 YEARS FROM THE BIRTH OF PROF. FRANTlSEK BEHOUNEK

C.Jech The .1. tleyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 I'ruhu 8, Dolejskova 3, Czech Republic

On 28 October of this year the 100 anniversary of the birth of Frantisek Behounek, the renown Czech scientist, writer and polar explorer will be remembered. He graduated from the Charles University, spent two years at the Curie Laboratory in Paris, collaborating mostly with Irene Curie, and then started his own scientific career by studying radon concentrations in the spring waters in Joachimsthal. As a young man he devised an ambitious project to study atmospheric electricity and cosmic radiation during polar expeditions with the airships Norge and Italia He survived the lllfated impact of Italia on polar ice and the subsequent involuntary drift on the icefloe He described the adventurous history of polar flight of Italia in a successful book which was then followed by a number of adventure books for children, popular science and sci-fi books. Through his life Behounek remained dedicated to science which he pursued at the State Radiological Institute, being particularly interested in the radioactivity in the environment and in biological effects of ionising radiation. Later on, he supervised dosimetry at the State Radiotherapeutical Institute and ultimately founded the Institute of Radiation Dosimetry of the Czechoslovak Academy of Sciences. Prof. Behounek was an excellent university teacher and is remembered by his former students and young readers of his books.

-36- EMANATIONS AND "INDUCED" RADIOACTIVITY: FROM MYSTERY TO (MIS)USE

Z.I.Kolar Inter/acuity Reactor Institute, Delft University of Technology, Mekehveg 15, 2629 JB DELFT, The Netherlands

In 1896 H. Becquerel found that uranium salts emit invisible radiation capable of darkening photographic plates wrapped in black paper. Later he noticed that this radiation could discharge an electroscope. In 1898 G. C. Schmidt and M. Curie reported that thorium and its compounds could bring about the same effects. In the same year discoveries were published of two radioactive substances, namely polonium (P. Curie and M. Curie) and radium (Cunes and G. Bemont). Both were isolated from an uranium mineral, the pitchblende originating from St. Joachimstahl, Bohemia in Austria-Hungary now Jachymov, Bohemia in Czech Republic. In 1899 the Cunes reported a mysterious property of radium, namely its ability to convey radioactivity to neighbouring materials. At about the same time E. Rutherford concluded that "thorium compounds emit radioactive particles ..., which retain their radioactive powers for several minutes". This "emanation", as he named it, acted "like an ordinary gas". Moreover, the thorium compounds (like the radium ones) produced temporary radioactivity in any solid substance placed in their vicinity. This kind of radioactivity was soon referred to as "induced" or "excited" radioactivity. Eventually three emanations, all gaseous, were discovered: radon, called first niton (1900: E. Dom), thoron (1899: R. Owen, 1900: E. Rutherford) and actinon (1902: F. O. Giesel) emanating from radium, thorium and actinium, respectively. Emanations disintegrate into radioactive products which by depositing at solid substances give rise to "induced" radioactivity. At the turn of the century a zero valency column of rare, chemically inert gases (, , , and xenon) had to be added to the periodic table of elements. In the course of time it became evident that the emanations belong to the same group of gases. Today it is known that the emanations are actually radioisotopes of the same element, the inert gas radon. Thus "radon" is "Rn (half-life, h, = 3.823 days), "thoron" is ^Rn (t* = 55.6 s) and "actinon" is 2!9Rn (t>, = 3 96 s). Following the discovery of emanations the research involving them and their disintegration products became very popular. The identity of a number of these radioactive products was soon established "Cunum-emanation", i.e. radium-emanation, was used as a source of Ra D (21l>Pb) to be applied as an "indicator" (radiotracer) for lead in a study on the solubility of lead sulphide and lead chromate. This study was earned out by G. von Hevesy and F Paneth and published in 1913 It is actually the very first publication based on the G. von Hevesy's concept of radioactive indicators (radiotracers)! Shortly after the advent of radium it was noticed that it must be handled with precaution. Strong radium preparation could cause skin burns to develop. Later it was suggested that radium might have an application in medicine. Betterment in some skin diseases as a result of irradiation with radium emitted rays was reported. Carcinoma appeared to respond to such treatment as well. Moreover, the healing (?) action of natural springs (spas) has been attributed to their content of radium emanation i.e. radon. Inhaling radon and dnnking radon-containing water became an accepted medicinal use (or misuse ?) of radium emanation.

UEXT PAGIfS) 37 , 8ef t BLANK Topic 1 CHEMISTRY OF NATURAL RADIONUCLIDES, DISCOVERY OF RADIUM AND POLONIUM

Poster presentations

-39- Pl-l

ON THE VALENCY OF URANIUM IN AEGIRINE AND ON BEHAVIOUR OF ISOTOPES 234U AND 238U AT DISSOLVING THE MINERAL

K.V.Bogdanov, Ju.F.Batrakov, D.E.Maslennikov, E.V.Puchkova, A.S.Sergeev St.Petersburg State University, St.Petersburg, Russia

The work is aimed to study a correlation between observed ratio of the activities of uranium isotopes (AR=234U/238U) and their oxidation states in aeginne The samples of aeginne was separated out of metasomatic rock of the Kola peninsula The mineralogical analysis showed the contents: aegmne (70+75%), albite (18 %), pyrochlore (1 %), magnetite (1+5 %), calcite ( 1 %). The X-ray chemical shirts of ULoii -line have been measured applying 2 M bent Crystal Spectrometer. The results indicated for all components of rock the presence of only U(YI) with the exception of aeginne, where up to 50 % of uranium were found to be close to U (IV) . In contradiction with the X-ray experiment the presence of U(1Y) was not found during multiple leaching of aegirine even in concentrated hydrochloric acid (up to 117 mole/1 provided that cpu varied from 0 4 to 1 volt). To make it clear what is the mam cause of this disagreement the line (ULpi ) was chosen to obtain additional information A correlation diagram has been created with the coordinates SULcti and SULpi and its application allowed to proof, that various aegirine samples could contain (31,5 ±1,5) % U (VI), (51 ±8) % U (V) and (17±9) % U (IV) There appeared a hope based upon the X-ray observations that the concentrated hydrochloric acid completely leached from mineral U (V) and in a smaller degree U (VI), while U (IV) was preserved in the Rest. As to dissolution of U (V) concerned it was surprisingly strange that the process did not manifest any sings of the well known disproportionate as if it resulted in direct oxidation of U (V) up to U (VI). The presence of U(Y) in the mineral seems to be the main cause of possible deficits of isotope 234U, both in mineral as a whole and in extracts. Those parts of a mineral surface , which were the most accessible to natural waters and weathering processes , occur to be poorer as to 234U up to value AR=0,73 (while a ratio 234U/238U =0,92 for completely dissolved aeginne). In deeper layers of structure the ratio of isotopes 234U/238U (Bq/Bq) comes nearer to equilibrium Pl-2

ORGANIC SUBSTANCE AS A COLLECTOR OF RECOIL ATOMS 234Th ^234yj ,N BLACK SHALES

R.V.Bogdanov, S.A.Gerasimov, S.A.Ozernaya, A.A.Pihlak", A.S.Sergeev. St.Petersburg State University, St. Petersburg, Russia " Institute of Chemical and Biological Physics, Academy of Sciences of Estonia, Estonia

It was shown earlier, that the black (dictyonemic) shales of northern Estonia are characterized by the equilibrium ratio of even : AR=234U/238U=I. A separation of isotopes 2M\J and 238U takes place, however, between various mineral components of rock as a result of recoil effects of atoms 234Th (°*V). The role of organic substance (OS) of the shale in nuclear- chemical processes, accompanying of the 238U is still obscure. In the present work samples of the dictyonemic shale from drill core of a bore hole ' 191-a on Estonia (samples 2299 and 2306) were investigated The interaction of uranium with OS was confirmed by correlation between specific activity of uranium and contents of the OS in fractions received by electrostatic separation of the ground shale powder. For revealing of organic components which have different from the equilibrium ratio of uranium even isotopes, a scheme of consequent solid phase extraction of hydrocarbons, pitches, waxes and asphaltenes, humic substances from the shale accordingly by an ether, hexane, benzene and pyndine was used. Each extraction was earned out during several days in the Soxhlet apparatus at temperature close to boiling temperature of each solvent. For more complete dissolution of humus the rest was processed by 1 M NaOH solution at room temperature during one day In each extract isotope ratio and share of leached uranium were determined. The values of AR significantly exceeding equilibrium, are found out in fractions of pyndine (1,72 + 0,06) and alkali (1,47 + 0,03) extracts with the contents of B8U 0,3 % and 8,1 % respectively. Preliminary estimations show that the probability of the hit of recoil atoms into alkali soluble component of humus is 17-20 times higher than into pyndine extractive component. Therefore alkali soluble component is the basic collector of recoil atoms and is responsible for accumulation of uranium at formation of dictyonemic shales. The thickness of the uraninite film covering this chemically active component of OS in sample 2306 is estimated as 35 nm or less.

-4]- Pl-3 URANIUM AND THORIUM BEHAVIOUR IN ENDOGENIC PROCESSES. GEOLOGICAL OBSERVATIONS AND EXPERIMENTAL RESEARCH

S.V.Ioudintsev and B.I.Omelianenko Institute of Geology of Ore Deposits, Moscow, Russia

Study of uranium and thorium geochemistry in magmatic processes has a great importance for natural melts origin and evolution, and their ore-bearing estimation as well. Recently data on the nuclides behaviour have been used for description of radionuclides migration in geological media around High Level Waste repository. Experimental and geochemical data allow to conclude the following: 1. Study of uranium bearing glasses absorption spectra gave evidence that U1V dominates in natural melts, and some amounts of UV and UVI may also coexist. The data are consisted with uranium state in silicate, alumino-phosphate, and boron-silicate glasses considered as matrices for High Level Wastes immobilisation. 2. Solubility of U and Th in melts increases with temperature, melt alkalinity, and partial pressure (uranium only). 3. Distribution coefficients of Th and U between fluid and melt are estimated to be 0.01-0.1, depending mainly on fluid composition. 4. Behaviour of U and Th during melt crystallisation is governed by the following distribution coefficients' values: 0.01-0.2 for quartz, feldspar, biotite, amphibole, and pyroxen; 2-6 for apatite; 10-300 for sphene, allanite, and zircon; 100-3000 for monazite, and thorite. The data are employed for description of the elements behaviour during crystallisation of magmatic melts. 5. In the course of solidification U and Th enrichment occurs in the residual melt because of their bulk distribution coefficients between total set of minerals formed and melt vary in the range 0.1-0 3. 6 At the late stage of crystallisation U contents in the melt reach 0.01-0.02 wt.%. The values are close to saturation level, leading to uraninite formation. The element contents in coexisting fluid are also determined by uraninite solubility, and correspond to O.OOn wt.%.

-42- Pl-4

ATTEMPTS TO MOBILIZE POLONIUM-210 IN THE BODY

J.Rencova1, V.Volf1, M.M.Jones2 and P.K.Singh2 'National Institute of Public Health, Centre of Industrial Hygiene and Occupational Diseases, Srobdrova 48, 100 42 Prague JO, Czech Republic 2Vanderbill University, Department of Chemistry, PO Box 1583, Station b, Nashville, Tennessee 37235, USA

Polomum-210 belongs to the most hazardous alpha-emitting radionuclides although it has a relatively short physical half life (138 4 days). Accidental internal contamination of humans with 210Po have been reported in occupationally exposed persons and even in children. Internal contamination of the body with 210Po as well as with other alpha-emitters represents a serious health risk for which current treatment procedures are only of marginal efficacy. Radioactive elements are incorporated into soft tissues and skeleton Their decay gives rise to tissue damage (malignances, haemopoietic and genetic impairment) Therefore, the possibilities of decreasing deposition and increasing excretion (mobilization) of radionuclides are searched. The content of radionuclides as well as of heavy metals in the body may be reduced by the treatment with chelating agents A survey of the efficacies of clinically used and newly developed chelating agents is given Polonium has a high affinity for sulphydryl groups and thus chelating agents containing these groups are the most suitable for its decorporation. In the first attempt to remove ''uPo from the body 2,3-dimercaptopropanol (BAL) was used. Subsequently, different derivatives of BAL, dithiocarbamate, pemcillamine, dimercaptosuccinic acid and 2,3- dimercaptopropylphtalamidic acid were investigated All these compounds act as chelating agents for 2l0Po in vivo but none of them can be considered as optimal. In general, a marked decrease in 210Po retention in blood, spleen and bone could be achieved by the treatment, nevertheless, in several other organs 210Po accumulation was enhanced. Consequently only moderate reduction of overall 2l0Po retention was achieved. The goal of our experimental studies conducted in the last several years was to develop new chelating agents that would be effective in mobilizing 210Po from the body Most chelating agents come into contact with the radionuclide in blood plasma and extracellular fluids It is, however, desirable to synthesize such chelating agents which could pass across cellular membranes and reach the radionuclide at its intracellular binding site Our experiments on rats have demonstrated that there are two classes of chelating agents which appear convenient for the search of more effective antagonists for polonium intoxication : dithiocarbamates and vicinal dithiols. Different substitutions in a molecule resulting in changes in the ratio of nonionic polar to nonpolar substituents lead to alterations in the therapeutic efficacy Following administration of chelating agents, there is a pronounced redistribution of polonium toward and into the organs through which chelating agents are transporting polonium for excretion. For some of the chelating agents this is primarily the kidney, for some the liver and for others, both organs. The results also indicate that several chelating agents are able to remove polonium from one or more organs, but are apparently not able to carry polonium past competing binding sites in the kidneys and the liver. 210Po has varying degrees of affinity for the various types of tissues where it is deposited and redeposited pnor to excretion. Therefore, protracted treatment is necessary to transport 210Po towards the ultimate excretion point. The highest concentration of 210Po (% injected 210Po per g wet tissue) is found in the kidneys, spleen and liver. It is notheworthy that the treatment with diethyldithiocarbamate and bis-dithiocarbamate derivatives substantially decreases 210Po content of these organs.

-43- Pl-5

POLONIUM, URANIUM AND PLUTONIUM IN THE SOUTHERN BALTIC SEA Bogdan Skwarzec Polish Academy of Sciences, Institute ofOceanology, ul. Powstancow Warszawy 55, 81-712 Sopot, Poland

210 23 24O The analysis of seawater samples revealed that the mean concentration of Po and ** pu jn Baltic water were 0.6 mBq dm"3 and 4.8 uBq dm'3, about 75% of which consisted of soluble forms. Polonium and plutonium are strongly accumulated by organisms. Their mean values of bioaccumulation factor (BCF) fell within the range from 9 ' 102 to 3.5 104 In the case of plankton organisms, the values of polonium BCF increase in sequence: phytoplankton < macrozooplankton < mesozooplankton, while in the zoobenthos they increase in following order: Polychaeta < Priapulida < Malocostraca < Bivalvia (soft tissue). It was additionally demonstrated that metabolic organ in fish (intestine, liver, spleen, pyloric caecal) contain much higher 210Po concentrations than the muscle tissue. Baltic plants and benthic animals concentrated plutonium to various extents. In the seaweeds the 23 2 > highest plutonium ** * pu concentration were found in Pilayella litoralis. In the zoobenthos, plutonium concentration were higher in Priapulida and Polichaeta and lower in Eutromastraca, Malacostraca and Bivalvia (soft tissue). The impact of the Chernobyl plutonium on the benthic organisms was calculated at about 10%. In contrast to the polonium and plutonium, Baltic organisms concentrated uranium isotopes (234U, ^'U) only to a small degree, and mean BCF values of this element ranged from 1 to 55 Investigation on fish demonstrated that uranium is non-uniformly distributed in their bodies, the uranium concentration increasing in the sequence: muscle < sceleton < viscera. On the basis of the content of the analysed radionuclides in the Baltic samples it can be concluded that polonium circulates in the southern Baltic ecosystem in the same way that the organic matter does. On the other hand, sedimentation and diffusion from sediments to deep seawater are important ways in which uranium and plutonium migrate within this ecosystem.

-44- Topic 2

RADIONUCLIDES IN THE ENVIRONMENT, RADIOECOLOGY

Verbal presentations CZ9827759

USE OF SHORT-LIVED RADIONUCLIDES IN AEROSOL CHEMISTRY

H.W. GSggeler Labor fiir Radio- und Umwellchemie, Universitat Bern 3012 Bern, Switzerland and Paul Scherrer Institul CH-5232 Villigen, Switzerland

Short-lived radionuchdes are well suited to label small aerosol particles or to study heterogeneous reactions with such particles. Three different applications will be outlined

1) A 21lPb generator was developed which enables continuous detection of environmental aerosol particles at ultralow concentrations. This device - named epiphaniometer - is now in use worldwide, mainly at remote sites to study atmospheric transport processes.

2) Techniques developed in heavy element research are ideally suited for applications in aerosol chemistry As an example, the gas-jet device at the PHILIPS cyclotron at PSI was applied to continuously produce and transport I3N (TI,T = 10 mm) in form of 13NO. For production the reaction l6O(p,a)13N was used.

I3 Via oxidation NO2 was then formed and in-situ the interaction with carbonaceous particles investigated. For the first time, the formation of H0I3N0 on such particles could be observed, a reaction of high importance in the atmosphere with respect to OH radical formation during the night.

3) In a future project, short-lived bromide isotopes will be produced at the gas-jet facility of the spallation neutron source SINQ at PSI, in order to study heterogeneous reactions of brominated species with solid particles, a topic of high relevance in the context of the ozone hole problem. CZ9827760

BEHAVIOUR OF RADIUM ISOTOPES RELEASED WITH BRINES AND SEDIMENTS FROM COAL MINES IN POLAND

M. Wysocka, S. Chalupnik, A. Mielnikow, J. Lebecka, K, Skubacz Central Mining Institute, 40-166 Katowice, PI. Gwarkow I, POLAND

Saline waters occurring in underground coal mines in Poland often contain natural radioactive isotopes, mainly 226Ra from uranium series and 228Ra from thorium series. Approximately 40% of total amount of radium remains underground in a form of radioactive deposits, but 225 MBq of 226Ra and 380 MBq of 228Ra are released daily to the rivers with mine effluents. Technical measures as spontaneous precipitation of radium in gobs, decreasing of amounts of water inflowing into underground working etc. have been undertaken in several coal mines and in the result total amount of radium released to the surface waters diminished of about 60% during last 5-6 years. Mine waters can cause a severe impact on the natural environment. The enhancement of radium concentration in river waters, bottom sediments and vegetation is observed. Sometimes radium concentration in rivers exceeds 0.7 kBq/m3, which is due to Polish law a permissible level for liquid radioactive waste. It was necessary to undertake investigations for development the methods of the purification of mine waters from radium. The radium balance in effluents has been calculated and a map of radioactive contamination of river waters have been prepared. Solid wastes with enhanced natural radioactivity have been produced in huge amounts in energy and coal industries in Poland. There are two main sources of these waste products. As a result of combustion of coal in power plants low radioactive waste materials are produced, with 226Ra concentration seldom exceeding few hundreds of Bq/kg. Different situation is be observed in coal mines, where as a result of precipitation of radium from radium-bearing waters radioactive deposits are formed. Sometimes natural radioactivity of such materials is very high, in case of scaling from coal mines radium concentration may reach 400 000 Bq/kg - similar activity as for 3% uranium ore. Therefore maintenance of solid waste with technologically enhanced natural radioactivity (TENR) is also a very important subject.

-47- CZ9827761

RADIOMETRIC ANALYSIS OF SELECTED PHOSPHORITE DEPOSITS OF NORTHWESTERN SAUDI ARABIA

A. Aksoy, W. S. A. Matter*, and Z. R. El-Naggar* Energy Research Laboratory, Research Institute, * Earth Sciences Department King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

Natural gamma radiations in the Earth's crust mainly comes from the decay of three radioactive isotopes: Potassium-40 C°K), Uramum-238 (238U) and Thorium-232 (^Th). The decay chains of these 3 radioisotopes are illustrated in a figure. Natural Spectrometry Facility at the ERL was used on full time basis over a period of three months to measure quantitatively the natural gamma-ray activity in 50 selected phosphorite deposit samples from the northwestern part of Saudi Arabia. Samples were collected namely from Turayf area, Arar chalk, Tawil sandstone and Umm Wual regions. Each sample was crushed, placed in a 3"xO5" cylindrical plastic container, air tight sealed to prevent any radon escape, and left for three weeks to allow 226Ra decay to reach the equilibrium in the B8U decay series. The sample was then placed on a 5"x5" Nal(TI) detector which was connected to a spectroscopy amplifier, an ADC AM Multichannel Buffer Ortec 918A model and a PC based data acquisition and analysis system. The setup has already been calibrated [1] using 14 certified standards of K, U and Th from IAEA, Austria and NIST, USA. Each sample was measured for 24 h to reach a good statistical accuracy of a few percent. Spectra were acquired in 4096 channels and calibrated with standard gamma-ray sources (60Co and 137Cs). This calibration allows three selected gamma lines of 1460 keV from 40K, 1765 keV from 214Bi and 2615 keV from 208TI to be evaluated. Here, the line of 1765 keV of 2l4Bi comes from 238U and 2615 keV of 2O8T1 from 232Th The integrated background-subtracted net counts under these peaks were compared with those from certified standards of known absolute concentrations of U and Th in ppm and K in wt.%. The results of the measurements show a U concentration between 9-127 ppm with an average of 42 ppm, Th concentration of 3-28 ppm with an average value of 10 ppm and K concentration in the 0.18-2.42 wt.% range with an average of 0.8%. The uncertainties were 0.3-4 % for U, 1- 17 % for Th and 0.7-15 % for K The results will be presented and further geological interpretation of the results will be discussed using the relation between the content of K, U and Th and P2O5 as well as from the relationship among uranium, thorium and potassium [2].

References: [1] A. Aksoy, A.A. Naqvi, F.Z. Khian, F Abujarad, M. Al-Ohah and M. Sumani, Nucl. lnstr. anJMelh. in Physics Research A 353 (1994) 558-561. [2] S A. Matter Wael, MS. Thesis, Geology of the Early Paleogene phosphorite deposits of Northwestern Saudi Arabia, Earth Sciences Dept KFUPM (1996).

-48- CZ9827762

IODINE-131 DISTRIBUTION ON THE TERRITORY OF THE REPUBLIC OF BELARUS DURING THE FIRST PERIOD OF THE CHERNOBYL NPP CATASTROPHE

Germenchuk M.G., Zhukova O.M., Shagalova E.D., Matveenko I.I. Belarus Slate Department for HyJrometeorology, Republican Center of Radiation and Environmental Monitoring, Minsk, Belarus

During the initial period after the accident considerable increase of exposure dose was registered practically everywhere on the territory of Belarus The levels of radioactive contamination induced by iodine-131 were so high that the irradiation of millions people caused by it has been qualified by experts as the period of "iodine blow" by specialists. So reconstruction of iodine doses during the initial period after the accident can considerably change current assessments of radionuclides affect upon population of Belarus as a result of the Chernobyl NPP catastrophe. Meteorological conditions of the radioactively contaminated air masses movement from April 26 to May 10, 1986 practically determined the main zone of radioactive fall-outs in the north-west and north-east directions from the Chernobyl NPP because during this period the air masses contaminated with radionuclides passed over all the territory of the republic of Belarus. To reconstruct space distribution of iodine-131 on the territory of Belarus we used the following data: - contents of iodine-131 in soil measured by gamma spectrometry method in May-July, 1986; - contents of iodine-131 in samples of radioactive atmospheric fall-outs measured by gamma spectrometry method in May, 1986; - daily measurements of exposure dose power levels on the territory of Belarus obtained in April- July, 1986; - results of aerial gamma radiation mapping, obtained in May, 1986; - daily measurements of radioactive contamination of milk on the territory of Belarus obtained in May-July, 1986; - measurements of iodine-131 content in links of biological chain "soil-grass-milk" sampled from 15 reference farms on the territory of Gomel, Grodno, Vitebsk, Brest, Mogilev and Minsk regions on May 17-22, 1986; - maps of specific activity of natural hayfields grass on the territory of Belarus (for every district) obtained on June 2 and 5, on July 3, 1986. Dose commitments on thyroid gland caused by iodine isotopes were formed mainly during the first 2,5 months after the accident. Local irradiation of this organ was stipulated by high accumulation factor of iodine isotopes in thyroid gland that caused increasing of malignant thyroid tumors incidences, including children, on all over the territory of Belarus. It should be noted that by January, 1986 two malignant thyroid gland tumor incidences among children were registered The space distribution of malignant thyroid gland tumor incidences among children on the territory of Belarus in the period from 1986 to 1995 is shown on. Comparison of iodine-131 distribution map and malignant thyroid gland tumor incidences among children on the territory of Belarus map shows that the more level of iodine contamination the more malignant thyroid gland tumor incidence. Reconstruction map of space iodine-131 distribution reflects real situation on the territory of the republic of Belarus on the 10th of May 1986. Proposed approaches allow one to construct a number of maps of iodine-131 distribution for given data taking into account dynamics of real meteorological conditions formed the radioactive trace. Series of reconstruction maps for different dates allow one to assess an external dose of gamma-irradiation caused by iodine-131.

-49- CZ9827763

PARTICULARITIES OF THE CHERNOBYLS TRACE FORMING IN BELARUS AND ITS DYNAMICS DURING THE POSTERIOR YEARS

Yu.K.Shchokin, Institute of Radioecological Problems of the National Academy of Sciences of Belarus

M.G.Germentchuk, O.M.Zhukova, I.I.Matveenko State Committee for Hydrometeorology, Minsk, Belarus

The complex of investigations, carried out at the initial period after the accident at ChNPP has shown, that as a result of transfer and fallout of radioactive materials a significant on the scale radioactive contamination of environment on Belarus territory has occurred. A lot of measurements were made, from which become clear that at the first time in the world practice a catastrophe of so large scale and with such complex picture of radiation consequences has occured. In spite of the great volume of performed work, at the early period it was impossible to cover by sufficiently dense scale of measurements the whole territory of republic. That caused an important loss of experimental information, especially with respect to short-live isotopes. This not always allows to compare uniqualy medical consequances with doses of irradiation of different categories of the population. In this connection the problem of reconstruction of isotope composition of radioactive fallouts is actual until present. This work is aimed to the solution of such problem by the using a complex method that includes both results of direct mesuarements, recieved at a different time, and accounting- theoretical models, allowing to reconstruct an initial contamination. As an experimental base of our investigation we used a computer database of spectrometnc measurments of soil samples, obtained at a different time, as from first days Moreover, data on contamination of milk and other foodstuffs, vegetation were taken into account, as well as known data on the dynamics of source power and changes in the meteorological situation at a period of a radioactive trace forming. Recieved results allow to get more detail picture of radioactive contamination of territory of Belarus, and to understand better a dynamics of its forming, as well as to make the prognose of changing its isotope composition at following years They also give more full set of data for the evaluation of doses, recieved by the population of Belarus.

-50- CZ9827764

COSMOGENIC RADIONUCLIDE CARRIERS IN THE ATMOSPHERE

G. Lujaniene, V. Lujanas Institute of Physics, A.Gostauto 12, 2600 Vilnius, Lithuania

In the investigation of various processes taking place in the ambient environment, radioactive substances appear to be good tracers. On the other hand, the behavior of radionuclides in the environment is determined to a great extent by physico-chemical properties of their aerosol carriers, particularly by their solubility and size. 7Be and other cosmogenic radionuclides are widely used as tracers to investigate processes that take place in the atmosphere. The knowledge of physical and chemical properties of their carriers is therefore very important. Cosmogenic radionuclides, formed during the interaction of cosmic rays with the nuclei of air atoms and passing to the gaseous phase, convert into aerosols The formation of 7Be, 32>33P, 35S aerosol carriers in the atmosphere proceeds via various processes such as nucleation, coagulation, condensation, etc. Aerosols were sampled on perchlorvinyl filters of the FPP-15 type by pumping large volumes of air (up to 400,000 m3) through the filters. The samples were collected in the wooded outskirts of Vilnius and Preila. Filters were exposed in a special building (with blind walls) at the height of 1 m above ground. Chemical and radiochemical analyses were carried out as described by us previously. The investigation of radionuclides (7Be 32'33P and 35S) and stabile and phosphorus forms was based on the Tessier sequential extraction method. Our investigation shows that properties of radionuclide carriers can be transformed in the atmosphere in a very short time (days, hours), whereas in soil and hydrosphere such changes can be observed only during months or years. Oxidation processes proceeding in the atmosphere induce changes in the 7Be 32'33P aerosol earner properties. The aerosol can be characterized by low pH and high Eh values corresponding to high 7Be solubility. The unexpectedly high negative Eh values obtained in dry summer period, when due to low humidity the intensity of oxidation processes decreases, indicate that the 7Be 3233P aerosol is in this case evidently bound to insoluble carriers. It should be noted, that 137Cs solubility does not depend on changes in pH. It can be explained by the fact that - in contrast to 7Be - l37Cs is associated with the exchangeable fraction. Cesium ions can be replaced not only by PT but also by NUT and other ions Furthermore, it should be noted that 7Be aerosols collected at the seaside of the Baltic sea (Preila) were found to be more soluble than those in Vilnius, their solubility was up to 50-90 % and clear dependence between 7Be solubility, pH and Eh was not observed. It can be attributed to differences in the atmospheric aerosol composition (e.g. soluble chlorides) in Vilnius and Preila. A great variety of 7Be carriers properties as well as their dependence on the season and the existence of admixtures in the atmosphere require great caution in applying this isotope in tracer investigations. Thus, it should be taken into account that soluble carriers are removed faster from the atmosphere by precipitation. The significance of this fact is confirmed by the ratio of 7Be/32P in the air and precipitation obtained by us. It is evident that both soluble and insoluble aerosols can be formed depending on the environmental conditions. The capture of aerosol particles by cloud constitutents and also by drops in the layer under the cloud depends on many conditions and specifically on physico- chemical properties of aerosols - radionuclide carriers. Their properties change depending on residence time, layer of the atmosphere, etc. Undoubtedly, aerosol sizes, their solubility, electric charge, play an important role in the cleaning of air masses, and in this way they condition radionuclides concentration in the atmosphere and in precipitation.

-51- CZ9827765

THE ROLE OF ISOMORPHISM IN THE FORMATION OF MIXED RADIOACTIVE AEROSOLS

IN. B. Mikheev, S. A. Kulyukhin, and M. Z. Kazakevich Institute of Physical Chemistry, Russian Academy of Sciences, Moscow, Russia

Currently, the problem of nuclear power plant safety is considered one of the major factors limiting a large-scale advent of nuclear energy Special hazard comes from serious accidents, when the containment seems the only protection against outburst of radioactive aerosols and volatile radionuclides into the environment. But the containment, however, does not appear to be an ideal means of protection, since considerable amounts of both radioactive aerosols and volatile radionuclides usually do penetrate into the environment through leakages existing in the containment. It has already been established that about 30 per cent of Csl aerosols, formed in the course of severe nuclear power plant accidents, have sizes of particles of the order of nanometers Such particles can stay in the steam-and-air phase inside the containment for a long time, and penetrate into the environment through leakages Moreover, such radioactive aerosols are hydrophobic. In order to speed up sedimentation of aerosols it is necessary that they get coagulated This could most successfully be achieved if radioactive aerosols are cocrystallized with some artificially formed aerosols Since Csl is the main component of radioactive aerosols, formed during serious nuclear power plant accidents, our research was basically focused on studying agglomeration of Csl through cocrystallization. We have studied agglomeration of Csl aerosols with those of KG, NH4CI, NH,Br and M0O3. Cesium iodide and potassium chloride are known to be isostructural, and they have near similar melting and boiling points. When Csl and KG jointly evaporate in their steam phase, their components become mixed. This to the formation of one single aerosol, which is a solid solution of the components. However, this process does not occur under joint evaporation of Csl and M0O3. Such mixed aerosols are a product of agglutination of heterogeneous aerosol particles and can easily disintegrateprovided there is an outside agent. Finally, we have studied cocrystallization of Csl aerosols with NH4CI and NHjBr. It was found that Csl aerosols, irrespective of the size of their particles, enter into the NH4G or NHJBr globules, while in the process when these globules are being formed. This results in the formation of a dispersed solid solution, not a true solution, as proved by electron microscope technique. The results obtained make it possible to conclude that isomorphism of components plays a very important role in the formation of mixed aerosols of these components, when the microcomponent (radioactive aerosol) enters into the inner structure of the macrocomponent aerosol.

This work was supported by the Russian Foundation of Fundamental Research (grant 97-03- 33608a)

-52- CZ9827766

RADIOACTIVE CONTAMINATION OF THE DNEPR-SOZH RIVER BASIN IN BELARUS AFTER THE ACCIDENT AT THE CHERNOBYL NPP

Olga M.Zhukova, Ivan I.Matveenko, Yurij M.Pokumejko, Ella D. Shagalova State Committee for Hydrometeorology, Republican Centre of Radiation and Environment Monitoring, Minsk Belarus

The radioactive contamination of the watershed of the Dnepr-Sozh basin in considered in the presend work. There is the Belarus - Bryansk caesium spot at its territory. Study of the dynamics of radioactive contamination of the river network of the Republic of Belarus is of great scientific and practical interest because the rivers as the most mobile part of the hydrosphere are of significant importance for the process of transport pf radionuclides at large distances, and in many cases their contribution to the processes of redistribution of radioactive contamination along the territory can be determinative. The systematic control over the radioactive contamination of surface waters is carried out at five main rivers of Belarus: Dnepr, Sozh, Pripyat, Iput, Besed. The experimental watershed of Iput river ( Dnepr-Sozh basin) have been chosen for revealing the general rules of radioactive contamination of the rivers of Belarus on the basis of generalization of the monitoring data and field investigations. The studies of the experimental watershed are earned out in two sites: Vylevo village and Dobrush town The main characteristics of the chosen sites are as follows: • the watershed area is characterized by rather high density of soil contamination with caesium-137 ( Vylevo - 2220 kBq/ nr ), • Dobrush site is the outlet of Iput' river, the density of soil contamination with caesium-137 in this area amounts to 185- 555 kBq/ m2 At the chosen sites (Vylevo, Dobrush) the observation of hydrological regime is carried out water level, temperature, discharge. The surface water is sampled and analysed monthly for determination caesium and strontium activity The bottom sediments have been sampled and analysed for determination of caesium-137, strontium-90, plutomum isotopes activity, the granulometnc analysis of the active layer of bottom sediments is carried out and the activity of radionuchdes on different fractions is determined. It has been found, that transport of radionuclides on suspended solids is one of the main forms of migration of radionuclides in the river (caesium-137 in particular) Thus, the analysis of contamination of the rivers of Belarus has shown, that the most intensive runoff of radionuclides from the territories of the watershed occurs in the head of the Dnepr basin, namely by its tributaries, Iput and Sozh. The annual runoff of radionuchdes in soluble form by the rivers of Belarus in 1987-1996 has decreased significantly Transport of radioisotopes with suspended and drawn wash loads significantly affects their migration and its contribution to the total runoff of radionuchdes has increased with time The runoff of radionuclides with transported wash loads varied within 20-80% from the total runoff of radionuclides. Sedimentation of river suspended load carrying radionuclides in the sites with slow river flow creates local movable ecologically dangerous centres of accumulation of radionuchdes in bottom sediments particularly in front of the diverting dams. Existence of such centres of radioactive contamination requires their monitoring, assessment of their possible effects, and, if necessary, their decontamination.

-53- CZ9827767

INVESTIGATIONS ON THE CAESIUM-137 HOUSEHOLD OF LAKE LUGANO, SWITZERLAND

J. Drissner1», T. Klenk", E. Klemt", R. Miller", G. Zibold", M. Burger2», A. Jakob2' 1) Fachhochschule Ravensburg-Weingarten, 1AFStrahlungsmeßtechnik, Postfach 1261, D-SH241 Weingarten, Deutschland 2) OK, AC-Laboralorium Spiez, Sektion Sicherheitsfragen, Zentrale Analytik und Radiochemie, CH-3700 Spiez, Schweiz

Sediment samples were taken from different basins of Lake Lugano and the vertical distribution of caesium-137 in the sediment was measured In all samples, a distinct maximum in the distribution can be attributed to the 1986 Chernobyl fallout. From the position of the maxima, we deduce sedimentation rates of the order of 5 to 10 cm within 10 years. Chernobyl caesium-137 inventories in the sediment vary between 10 and 110 kBq/m2, whereas the direct input through the lake surface caused by the Chernobyl fallout amounted to 22 kBq/m2. Close to tributaries, typical specific activities of about 1 kBq/kg can still be found in the top layer of the sediment. This relatively high specific activity can be explained by a continuous input through the tributaries. At all locations, 5 step caesmm-137 extraction experiments on sediment samples result in percentages of extracted caesium which are at least a factor of 2 up to a factor of 8 higher than those of Lake Constance sediments where the caesium is strongly bound to illites. Consequently, an enhanced potential for caesium-137 to redissolve into the pore water and ultimately into the water of the lake has to be assumed. Our findings are consistent with the 1996 measurements of the specific activity of the pore water of Lake Lugano sediments of about 400 mBq/1 and that of the lake water of 8 to 43 mBq/l close to the ground and 3 to 8 mBq/l close to the surface. The specific activity of the water of the main tributaries Vedeggio and Cassarate is of the order of 10 mBq/l. Thus, including the measured cation exchange capacity (CEC) of about 400 to 500 mval/kg and a total caesium K

-54- CZ9827768

COMPARISON OF DESORPTION OF RADIOCAESIUM (Cs-137) FROM SEA BOTTOM SEDIMENT AND NEAR-SHORE REGION (THE BALTIC)

Danuta Knapinska-Skiba, Ryszard Bojanowski Institute of Ocecmology PAS, ul. Powstancow Warszawy 55, 81-712 Sopot, Poland

Results of radiocaesium leaching from both littoral and sea bottom sediments in laboratory and field conditions are presented. Suspensions of sediment in seawater of varying content in the range from 1.4 gdm'3 to 16.5 gdm'3 were tested. Minimum detectable activity of the instrumental b-counting set up was 3 mBq. After ten days of littoral sediment leaching with seawater the amount of leached radiocaesium was below the detection limit. The behaviour of marine sediment is opposite to that of the littoral one Under similar conditions from 4% to 12% of radiocaesium is leached to seawater. The diffusion of radiocaesium from marine sediments to the overlying seawater was as calculated according to the Fick's low and utylising the measured concentrations of radiocaesium in the pore and the near-bottom seawater was estimated to be of the order of 0.001 Bqcm"2year"!.

-55- CZ9827769

INVESTIGATIONS OF THE DISEQUILIBRIUM BETWEEN Ra-226 AND Po-210 IN SOILS, RIVER SEDIMENTS AND VEGETATION IN THE VICINITY OF COAL MINES

S. Chalupnik, A. Mielnikow, M. Wysocka, B. Michalik, J. Lebecka CENTRAL MINING INSTITUTE, 40-166 KATOWICE, PL. GWARKOW1, POLAND

As a result of a discharge of the radium-bearing waters from coal mines into rivers a significant increase of radium concentration in bottom sediments can be observed. Sometimes also a contamination of nver banks, soils, and vegetation occurs. Mine waters contain mainly radium isotopes, i.e., Ra-226 from uranium series and Ra-228 from thorium series Due to chemical properties of such brines, these waters contain usually no uranium, no thorium and rather seldom elevated concentrations of other isotopes as lead (Pb-210) and polonium (Po-210). The deposition or adsorption of radium on river sediments may take place on a distance of several kilometers from the discharge points After a deposition or adsorption of radium isotopes the built-up of the activity of their progeny begins Therefore concentrations of radium isotopes are higher than the decay products. We are able to measure the disequilibrium in Ra-226 as well as in Ra-228 decay chain, which shows the approximate age of the deposit. On the other hand, in upper layers of soil and in vegetation very often higher activities of lead and polonium than radium are measured. The reason of the enhancement is the fall-out of radon progeny from air on the plants and soil surface. Radium is transported into plants through the root system, and this pathway is not very efficient accordingly to the fact, that radium is normally present in soil in an insoluble form (as sulphate), even on areas contaminated by radioactive deposits. Investigations were done in selected areas in the Upper Silesian Coal Basin.

-56- CZ9827770

ACTINIDES AND THE ENVIRONMENT: WHAT WE KNOW AND WHAT WE NEED TO KNOW

H. Nitsche Forschungszentrum RossenUorfe. V. , Institute of Radiochemistry, P. O. Box 510119, 01314 Dresden, Germany

Due to nuclear testing, reentry and disintegration of nuclear powered satellites, nuclear reactor accidents, uranium mining and processing, and nuclear weapons production, actinides have been introduced into the environment. Proposed disposal of high-level radioactive waste in mined repositories in geologic formations as well as the storage and disposal of uranium and plutonium from weapons dismantlement are farther possible sources for actinide releases to the environment In order to design methods for the cleanup of contaminated sites, predict the transport behavior in the environment, perform safety assessment studies to determine the ability of repositories to adequately contain them, and design ways to retard their release and migration rates, it is essential to understand the chemical behavior and forms of actinides under environmental conditions. Excluding gaseous and airborne transport, actinides can migrate in the environment mostly via aqueous media such as groundwater and surface, river, lake and sea water. Models predicting the hydrological transport through the environment require as input an actinide concentration, the true amount that is actually available for transport It is defined as the actinide source term and not as true solubility, because it may be a combination of dissolved and colloidal material Three major processes define the actinide source term: (1) solubility, (2) organic interaction, and (3) sorption They are dependent on each other and each individual process is the result of several sub-processes. Also, colloid formation plays a major role in the actinide source term, and it is common to each of the three main processes. The current state of knowledge of these processes will be discussed and areas will be outlined where additional information is required.

-57- CZ9827771

MIGRATION AND RETARDATION OF LONG-LIVED RADIONUCLIDES IN GEOSPHERE

V£ra Jedinakova-Kf izova Institute of Chemical Technology, 166 28 Prague, Czech Republic

The mechanisms of transport and retardation processes, chemistry and migration behaviour of radionuclides of fission products and actinides through engineered barriers is surveyed The ..critical group of radionuclides" is proposed for thorough investigation of their retardation properties. Some characteristics of natural sorbents with regard to their retardation properties and the effect of variations in the aqueous phase composition, pH-value and oxidation- reduction properties, complexation and other phenomena involved in radionuclides migration are discussed. Results are illustrated on caesium, strontium and technetium radionuclides The soluble impurities that may be present in the solid phase can influence the sorption behaviour of Cs* and Sr2* significantly. Attention is paid to thermodynamic modelling and its validation for evaluation of various phenomena in natural sorbents - ground water systems. The ion exchange model correctly predicts the sorption curve of Cs* and Sr2* onto bentonite as a function of Cs' and Sr* concentrations, respectively.

-58- CZ9827772

INTERACTION OF ACTINIDES WITH NATURAL MICROPOROUS MATERIALS: A REVIEW

P. Misaelides and A. Godclitsas Department of Chemistry, Aristotle University of ihessalomki, UR-54006 Thessaloniki, Greece

Natural microporous materials include several types of minerals such as zeolites, clay minerals, micas, iron- and manganese-oxides/hydroxides/oxyhydroxides present in various geological environments and soil formations. Their crystal structure is characterized by the presence of intracrystal micropores (channels or interlayer void spaces) providing high microporostty - surface area and distinguished physicochemical properties such as sorptive/ion-exchange and catalytic For this reason these materials have found a wide spectrum of industrial and technological applications. The investigation of the interaction of the actimde elements with natural microporous materials is of special significance for the nuclear industry because of the suitability of these materials for the treatment of liquid effluents and the final storage of radioactive waste (sorbents, backfill materials, constituents of disposal host rocks) produced in the nuclear fuel cycle. On the other hand, the environmental geochemistry of the actinides is of increasing importance because of their high radiotoxicity and their involvement in different geochemical and biogeochemical cycles. The transport of the actinide elements in the environment is mainly performed through aquatic pathways (streams, rivers, underground waters) and their mobility is strongly related to the interaction of their dissolved species with geological materials and especially with the highly sorptive microporous minerals. The existing studies mainly concern the sorption of Th, U, Np, Pu and Am from aqueous media by clay minerals (e.g. montmorillonite, kaolinite) and zeolites (e.g. heulandite/ clinoptilolite) as well as the determination of the corresponding chemical processes taking place at the mineral-water interface. The investigation techniques applied for this purpose include, except the conventional wet-chemical and radiochemical methods, advanced spectroscopic methods such as Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS), Rutherford Backscattered Spectroscopy (RBS), X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy These techniques significantly contribute to the characterization of the reacted mineral surfaces and to the explanation of the structural and compositional characteristics of the sorbed actinide species. Theoretical models regarding the aqueous chemistry and speciation of the actinides have also been developed aiming the elucidation of the complex actinide sorption mechanisms. Finally, this contribution also includes some recently obtained data concerning the interaction of actinides with todorokite (a naturally occurring microporous manganese-oxide of technological importance) and granitic micas (biotite) correlated with the nuclear waste disposal in geological formations.

-59- CZ9827773

INFLUENCE OF HUMIC ACID ON SORPTION OF 137Cs, 85Sr, 152154Eu AND 2MPu(IV) ON Ca-MONTMORILLONITE

I.S.Shaban, F.MacaSek, L'.Matel Department of Nuclear Chemistry, Faculty of Natural Sciences, Comenius University, SK-842 15 Bratislava, Slovakia

The effect of Aldnch humic acid (HA) on the capacity of Ca-montmonllonite isolated by sedimentation from water suspension of bentonite (Stara Kremnicka-Jelsovy potok, Slovakia) to sorb Cs-137, Sr-85, Eu-152 and Pu-239 was studied. The Sips isotherm for humic acid sorption, and multisite distribution model of ion sorption were found to suit well for description of mobility of ions as a function of equilibrium humic acid concentration in a role of single variable at given pH [1,2]. Now, an extended 2-sites-2-species model of M ion adsorption and chemisorption in presence of humic acid was elaborated and considered as follows: 1. Distribution of species between two sites of solid phase and solution: Dio and Dau are distribution ratios of metal species on a free surface and surface covered by humic acid, respectively (effectively, D20 is included in the two-phase stability constant P im). 2. Hydrolysis of the species, M2' + j H2O o M(OH)j MHp-,,A " + n H (the charge of complex is v = n+r-z), with effective homogeneous stability constant p°iu (L/g). 4 Chemisorption on the humic acid adsorbed on the solid phase, z+ M + {HPA'")S <-> {MHp-.,A""(s + mH' (u = m+r- z), with effective heterogeneous stability (interaction) constant p"im (dimensionless) Both the constants p in and P im can be found as the values related to Diu from the distribution ratio D vs. saturation degree s data concatenated with respective values of equilibrium concentration c of humic acid and activity of hydrogen ions an, and considering various stoichiometry (m and 11) The difference between distribution ratios of the Cs and Sr ions on a free and coated ("blocked") by humic acid surface was less pronounced than expected from some published data A strong influence on the polyvalent cations of Eu and Pu was fully confirmed but the two-site model of sorption was necessary to perceive complexation both in aqueous phase and also on the humificated surface The best data fit (Marquardt algorithm of Gauss-Newton iteration, program SigmaPlot™ 5 0 of Jandel Scientific) was obtained for the following values D10 (L/g) P,,/a,, 11 Los 3°,.,, ill Log P0,.. (Log P°,.,)/n Cesium 0.63 ± 0.10 0 1 -2.53 ± 0.91 1 <-25 <-25 Strontium 1.25 ± 0.20 6.6x10"' 2 -9.61 2 -15.18 -7.59 42 + 2 3.2x10"' 2 -13.04 3 -16.32 -5.44 42 ± 2 3.2x10"' 3 -14.20 3 -9.99 -4.99 Plutonium X.34 ± (1.(11 9.8 4 -3 36 ± 0 52 4 -6.24 ± 0 90 -1 56 ± 0.23 References 1. I.S.SHABAN. Influence of Huniic Acid on Mobility of sonic Radionuclides 111 Environment |Rcvicu|. Comenius University. Bratislava 1996. 2. I.S.SHABAN. F.MACASEK. Influence of Huinu: Substances on Sorption of Cesium and Slromium on Monlmorillonite, J.Radioanal.Nucl.Chem.. in press (1998)

-60- CZ9827774

SORPTION KINETICS OF 238U AND 237NP ON GLACIAL DEPOSITS

A.Braithwaite1, L.N. Moyes2, F.R.Livens2, D.Bunker2, C.Hughes3, S.Richardson1, J.T.Smith" and J.Hilton4, 'British Nuclear Fuels pic, Sellafleld, Seascale, Cumbria, CA20 1PG, 'Department of Chemistry, University of Manchester, Ml 3 9PL, 3Department of Earth Sciences, University of Manchester, Ml 3 9PL, ^Institute of Freshwater Ecology, East Stoke, Wareham, BH20 6BB.

Studies of uptake of radionuclides by natural materials have shown that sorption may occur via fast equilibrium exchange and/or slow kinetic processes, which can be described using a series of box models. This paper describes the use of such models to evaluate the solid-solution partitioning of 238U and 237Np on a clay rich deposit. Experimental data is obtained using the batch sorption technique, which is then analysed using 1, 2, and 3 box kinetic models. Uptake of B8U is initially rapid, with approximately 90% sorbed within the first 30 minutes. Sorption continues, but at a slower rate. Uptake of a7Np is initially slower than U, with approximately 30% sorbed within the first 30 minutes. Sorption again continues, at a slower rate. Analysis of the experimental data indicates that sorption can be described using 2 and 3 box kinetic models. The results demonstrates that sorption of uranium and neptunium on clay rich soil occurs via equilibrium and kinetically controlled pathways, with neptunium being controlled by kinetics to a greater extent than uranium. Sorption of neptunium can be described by the 2 or 3 box model, uranium requires the 3 box model

-61- CZ9827775

DIFFUSION AND DIFFUSION-CONVECTION EXPERIMENTS FOR STUDYING THE SORPTION OF RADIONUCLIDES ON SOILS

Frank Bruenjes, Holger Barnewitz, Gerald Kirchner University of Bremen, Dept. ofPhysics / FB 1, D-28334 Bremen, Germany

During the past decade diffusion experiments have been established as a convenient laboratory technique for studying sorption and desorption phenomena of radioactive trace substances on agriculturally used soils and on geologic media. Experimental results using the diffusion technique indicate that sorption of both cesium and strontium on soils may be described by nonlinear isotherms showing first-order kinetics (Kirchner et al., 1996). The present work aimed to investigate the potential effects of convective transport on the sorption characteristics of cesium and strontium on soils. For the diffusion-convection experiments, the through-diffusion technique was modified to allow for a constant pressure gradient over the soil pellet during the experiment. The design enables to choose various Peclet numbers which are a measure of the relative contributions of convective and diffusive transport. A wide range of soil types can be selected for the experiments including both soils with high (e.g., sandy soils) and with low saturated hydraulic conductivities (e.g., clay soils). For these experimental conditions, analytical solutions of the convection-dispersion equation exist if the sorption behavior of a tracer is characterized by a linear equilibrium isotherm For tracers showing concentration-dependent, kinetic sorption processes, an efficient numerical solution based on the finite-difference method (Barnewitz & Schaefer, 1993) was adopted. Both approaches are built into a nonlinear regression code in order to enable testing of various hypotheses concerning the sorption characteristics of the tracers studied. Data are presented for diffusion and for diffusion-convection experiments of strontium and cesium using a parabrown earth. The experimental data of both elements are modeled successfully by nonlinear isotherms with first-order kinetics. As the results show, both diffusion and diffusion- convection experiments offer convenient techniques to study sorption phenomena of trace substances in soils.

References

Barnewitz, H & R Schaefer. Model. Bio-Geosphere Processes, 2, 93-113 (1993) Kirchner, G.; Nageldmger, G. & R. Wellner Radiochim Acta, 74, 189-192 (1996)

-62- CZ9827776

RADIOCAESIUM DISTRIBUTION BETWEEN ORGANIC AND MINERAL PHASES IN ORGANIC SOILS

A. Rigol, M. Vidal, G. Rauret, C.A. Shand* and M.V. Cheshire* Dept. Je Ouimica Analilica. Universitat Ue Barcelona. Av. Diagonal 647, 0X028 Barcelona, Spain. "Macautay Land Use Research Institute, Craigiebuckler, Aberdeen, UK, AB15 XOH.

Radiocaesium is still of concern in contaminated areas because of its high plant availability in organic soils and thus the high transfer into the food chain This fact generates the need of research on interaction of this radionuchde with the soil phase in order to be able to design treatments capable of decreasing caesium availability in organic soils. It is already well known the key role of illitic clay minerals in the retention of radiocaesium in soils because of the existence of specific sites, known as Frayed Edge Sites (FES), whereas its interaction with the Regular Exchange Complex (REC) is usually weak. However, radiocaesium partitioning in organic soils is not yet completely understood. Some authors explain the high availability of radiocaesium in these soils in terms of the organic matter phase blocking the access to mineral sites, whereas others consider an exchangeable form in the FES because of the low rate of collapse. Therefore, the partitioning of radiocaesium between mineral and organic phases in highly organic soils must be clarified in order to understand the mechanisms of radiocaesium-soil interactions for the design of countermeasures based on soil properties In this work radiocaesium partitioning was studied in four organic soils, with an organic matter content (OM) ranging from 46 to 99% and with presence of illitic material in all of them, with the exception of the soil with 99% OM. For each soil, two fractions were derived after removing fats/waxes and humic/fulvic acids (humin+mineral), and after further removal of the mineral matter by an HF/HC1 treatment (humin). Two approaches were applied for the identification of the phase which most influenced radiocaesium behaviour. First, an adsorption approach was used to know if specific sites in the mineral phase controlled radiocaesium interaction with the soil by measuring the changes of the radiocaesium solid-liquid distribution coefficient according to the concentrations of competitive species in the solution in equilibrium with the soil. Second, a desorption approach was applied to define an exchangeable radiocaesium fraction which also allowed to investigate partitioning because of the dependence of the desorption yield on whether a di- or a monovalent cation was used for the extraction Two patterns were observed after applying the two approaches to the initial soils and each of their fractions. For samples derived from 99%-OM soil and also for all humin fractions, the increase of NHt concentration in the solution did not affect the radiocaesium distribution coefficient (KD) and no differences were observed between the desorption yields obtained with CH3COONH4 and CaCh, (around 80% for each extractant), indicating that radiocaesium may interact with REC when mineral matter is removed. The lack of a total extraction in these samples should not be taken to indicate an irreversible fixation in the humin, but simply showed an inefficiency of a single extraction to desorb all the exchangeable radiocaesium. With successive extractions the desorption yields obtained for these samples reached the 100%. For the other three soils and the humin+mineral fractions derived from them, an increase of NH» concentration led to a decrease in the KD and desorption yields from CaCk extraction were lower than when using CH3COONH4. This indicated that radiocaesium was associated with specific sites in the illitic material. Finally, the increase in the value of KD in the humin+mineral fraction compared with the initial soil suggested that humic/fulvic acids influenced partially radiocaesium interaction with the mineral phase.

-63- CZ9827777

DYNAMICS OF CONTENT OF MOBILE MSr IN SOILS IN CONSEQUENCE OF DISSOLUTION OF CHERNOBYL FUEL PARTICLES IN NATURAL CONDITIONS

S.I. Zvaritch Ukrainian Institute of Agricultural Radiology, Kiev, Ukraine

On the basis of experimental data on wSr forms in various natural soils and climate conditions on the fuel tracks of Chernobyl release, the portion of fuel particles which were dissolved by 1995 was calculated. The influence of some parameters of studied soils, such as acidity, content of humus, and other cations and hydrolysed , sum of adsorbed bases on the process of fuel particles destruction was investigated. It was shown that in real conditions the velocity of particles dissolution is influenced by the physical and chemical characteristics of the particles rather than the characteristics of the environment. Fuel particles of the first stage of the accident's release, located westward from the accidental unit of ChNPP, were found to be more resistant to the action of destructive processes, than those, which originated from the following stages. The possible explanation of the fact may be lower oxidation of the "western" particles' matrix because of higher temperature and shorter duration of the first stage of the accident. It was shown that no environmental factor, except the acidity of soil, influences the velocity of the fuel particles' dissolution. Mathematical dependencies of the velocity of fuel particles dissolution for western and other directions of the release on the acidity of soil were obtained. Prediction of radioactive substances leaching from the matrix of Chernobyl fuel particles for various types of soil in the exclusion zone at soil pH from 4 to 6 was done

-64- CZ9827778

SOIL SORPTION COMPLEX INFLUENCE ON DYNAMICS OF 239'240 Pu AND 241Am MOBILE AND FIXED FORMS IN DIFFERENT LANDSCAPES

S.L.Leinova, G.A.Sokolik, S.L. Kilchitskaya, T.G.Ivanova, N.V.Zhukovich, I.M.Kimlenko Belarussian State University, Laboratory of Radiochemistry, Minsk

2W240 241 The physico-chemical forms of pu and Am in soil (also including «hot» particles of fallout), specific radionuclide distribution between the mam components of soil sorption complex, biological accessibility of radionuclides in different landscape situations are analyzed. It was established that now the content of «hot» particles in soils of Belarus territory amounts to about 10-1.104 particles/m2. During the post accident period the «hot» particles quantity decreased 40-200 times and 50-20000 times in mineral and organogenic soils, respectively The activity of «hot» particles decreased 1.2-1.4 times per year in mineral soils and 1.3-1.5 times in organic soils The «hot» particle destruction velocity is determined by the soil media properties and the particle composition: the particles of ..condensed" nature are destroyed more quickly than particles of fuel nature. The velocity of release of transuranium elements from the «hot» particles increases with the increasing soil acidity and humus content in soils under otherwise equal conditions. The estimation of the content of radionuclides which have different bond strength with soil sorption complex was carried out by the method of sequential selective extraction. The share of the most mobile exchange forms of239"40 Pu is less than 10% The quantity of potential mobile acid soluble forms of" |40Pu increases with time and changes in the sequence: peat soils < soddy soils < soddy-podzohc soils. In mineral soils the higher content of acid soluble forms of 241Am (< 239/240 241 85%) in comparison with pu (< 40%) was found The increase in the content of Am mobile forms with soil depth is observed. It can be expected that in soils with high content of organic substances the accumulation of239'240 Pu and 24lAm in surface soil layers will take place in future, but in mineral soils significant amounts of radionuclides will enter illuvial horizons as a result of vertical migration. The processes of sorption and complex forming of transuranium elements by finely dispersed and ion-exchanging materials which model the main components of sorption soil complex were also investigated. Radionuclide transfer factors in meadow and forest plants was determined Practical recommendations which allow to regulate the physico-chemical forms and migratory ability of239'240 Pu and 241Am in soils are discussed.

-65- CZ9827779

APPLICATION OF X-RAY ABSORPTION SPECTROSCOPY IN RADIOECOLOGY

Tobias Reich and Heino Nitsche Forschungszentrum Rossendorf e. V., Institute of Radiochemistry, PO Box 510119, D-01314 Dresden, Germany

The contamination of the environment by toxic heavy metals and radionuchdes in particular, the remediation of contaminated soils and natural waters, and the management of hazardous radioactive waste have become an important concern throughout the world. In order to predict the behavior of contaminants in the environment and to design effective environmental cleanup strategies, the processes which determine the fate of the contaminants must be understood. Important parameters such as mobility, toxicity, and bioavailability of contaminants depend on their speciation which identifies the element, its physical state, chemical formula, and molecular structure. X-ray absorption spectroscopy is a powerful tool for providing molecular scale information on contaminants in solution, and in crystalline and amorphous solids. It permits the characterization of species which are important for chemical processing, waste management, and materials identification. Synchrotron-based x-ray absorption spectroscopy provides an unique method to determine short range structure from extended x-ray absorption fine structure (EXAFS) measurements and oxidation states via x-ray absorption near-edge structure (XANES) measurements. Speciation of a single element in a complex mixture can be achieved by measuring bond distances to neighboring atoms, and the number of such atoms can be determined approximately. Speciation information on non-ordered systems such as solutions, sorbates, and slurries can be obtained routinely from mililiter-size samples with millimolar concentrations of the element of interest. Thus the interaction of contaminants with soils, rocks, minerals, organic substances, and microorganisms in complex solid and aqueous natural systems can be determined Our report will focus on XANES and EXAFS investigations related to the legacy of the former uranium mining in the Erzgebirge, Germany. The following examples from research performed at the institute will demonstrate the basic principals and potentials of synchrotron radiation techniques in radionuclide and environmental science: adsorption of uranium (VI) on mineral surfaces, e.g., silica gel or femhydnte, interaction of uranium (VI) with humic acids, reduction of uranium (VI) by anaerobic microorganisms, and arsenic speciation in tailing pond water from a former uranium ore processing plant The presentation will conclude with a description of the Rossendorf Beamline (ROBL) operated at the European Synchrotron Radiation Facility (ESRF), Grenoble, France ROBL is the first beamline in the world dedicated to the study of radionuchdes by x-ray absorption spectroscopy. This facility, which will become fully operational in September 1998, has the capability of manipulating radionuclides in a containment box directly at the beamline.

-66- CZ9827780

THE ROLE OF PORE SOIL SOLUTIONS IN REDISTRIBUTION OF 137 M 239MO 241 Cs, Sr, pu AND Am WITHIN SOIL-VEGETATIVE COVER

S.V.Ovsiannikova, G.A.Sokolik, S.L.Kiltchitskaya, E.A.Eismont, N.V.Zhukovich, I.M.Kimlenko Belorussian State University, Laboratory of Radiochemistry, Minsk

The complex investigations of the pore soil solutions role in the migration of 137Cs, '"Sr, 239,240pu an(j 241^^ w^yyn soil-vegetative cover of natural ecosystems have been carried out. The 137 239>24 24I levels of contamination by Cs, '"Sr, °pu and Am of soil and grass vegetation samples, the radionuclide distribution along the vertical soil profiles and between solid and liquid phases of soils as well as the content of mobile (canonic forms and watersoluble complexes of radionuclides with soil components) forms of radionuclides in the soils of control points of observation have been estimated. The sampling sites are situated in the Gomel, Mogilev and Brest districts of Be- larus at the distance of 20-260 km from the Chernobyl nuclear power plant. The investigated pore solutions were obtained using the method of ultracentrifugation of water saturated soil samples (100% of the total water capacity). It was established that the soil solutions play an important role in the redistribution of 137Cs, s>ogr 239,240pu an£j 241^^ m me soii-p]^ systems. Obvious relationships between the distribution coefficients of radionuclides between solid and liquid phases (K

-67- CZ9827781

BIOLOGICAL ACCESSIBILITY OF CHERNOBYL RADIONUCLIDES AND ASPECTS OF ENVIRONMENTAL REHABILITATION

G.A. Sokolik, S.L.Leinova, T.G.Ivanova, V.V.Duksina, S.Ya.Rubinchik, V.V.Zaharenkov belarussiaii Stale University, Laboratory of Radiochemislry, Minsk

The necessity of this work is connected with the remediation of damaged territory, the development of new methods of manufacture of ecological safe products and the carrying out of different protective countermeasures for decreasing of dose to man as a result of external and l37 1J<> 23U MO M1 internal irradiation. The investigation of Cs, Sr, - pu and Am redistribution within natural ecosystems, the determination of natural and artificial factors influencing on processes of radionuclide migration on biogeochemical chains are made. The study of radiation situation dynamics, the behaviour of radionuclides in soil, water, inclusion of the radionuclides into food chains, accumulation in plant and animal organisms and estimation of biological effects was carried out. Beside this, the conducted estimation of effectiveness of possible remediation measures allows to determine the integrity of economical expense and also to find out the possible negative effects of environmental rehabilitation There are three main directions of investigation. The first of them is to estimate the intensity of self-purification of damaged region soil cover, taking into account landscape, soil, land-use differentiation and also peculiarities of physico- chemical occurrence forms of the radioactive fallout. In particular, the change dynamics of radionuclide physico-chemical state and vertical migration in soil of different genesis were estimated, the soil varieties with high and low rate of radionuchde migration were discovered, the peculiarities of "hot" particles destruction, the change of their dispersity and structure composition under the influence of natural reagents were studied, the radionuclide bond strength with some components of different soil types was determined The second problem is to estimate the biological accessibility of radionuchdes In particular, the radionuclide contamination of different components of forest and meadow phytocenoses was investigated, the change of radionuclide accumulation coefficients in system "soil -plant" was estimated The third problem is ecological and practice measures for environmental rehabilitation In particular, the soil self-purification hypothesis in different natural conditions were created and the permissible criterion's of interference in natural processes were developed.

-68- CZ9827782

A COMPARTMENT MODEL TO EVALUATE THE HALF-TIME OF 90Sr AND 137Cs IN PLANTS CHARACTERISTIC OF A SEMINATURAL MEDITERRANEAN ECOSYSTEM

A. Baeza(l), J.M. Paniagua(l), M. Rufo(l), J. Barandica(2), A. Sterling(3) (I) Dplo. de Fisica, Facultad de Veterinaria y Escuela Politécnica, Universidad de Extremadura, Avda. de la Universidad s/n IOO'1-Cäceres (Spain). (2) Dpto. de Ecologia, F. de Biologia, Universidad Compluleme Madrid, Avda. de la Complutense, 2H040-Madrid (Spain) (3) Consejo de Seguridad Nuclear, С Justo Dorado 11, 28040-Madrid (Spain)

We have studied the concentration of fallout radionuclides *'Sr and b7Cs in different vegetation compartments and in available and non-available soil fractions in a Mediterranean scrubland ecosystem. We found the two radionuclides to adopt different distribution profiles with depth in the soil, with a rapid decrease of the specific activity of 137Cs in the first 13 cm of soil, and a much slower decrease for ^Sr. The bio-availability of the radionuclides, quantified as the fraction extracted from the soil after leaching with ammonium acetate, was much greater for strontium than for caesium. The values for available strontium in practically all the soils analyzed lay within the range of 60 to 80%, which is far above the percentages of bio-availability of caesium, which were between 10 and 20%. Apart from there existing a greater percentage of available strontium m the soils, the soil-plant transfer (quantified on the basis of the activity existing in the available fraction of the soil) was much greater for '"Sr, one or two orders of magnitude higher than for l37Cs, depending on the part of the plant under consideration. The distribution of the two radionuclides once incorporated into the plants is different for the distinct fractions of the same Thus, ""Sr has a more structural behaviour, accumulating preferentially in the trunk-root, to a lesser degree in the leaves, and least in the fruit. However, the distribution of L37Cs in the different plant fractions that we considered was such that we detected practically no statistically significant differences between their respective specific activities. The application of a linear compartmental model to the soil-plant system allowed us to characterize the fluxes of the radionuclides, and to quantify their residence half-lives in the following processes, (i) the uptake of the radionuchdes by the root from the available soil fraction; (ii) the transfer of these isotopes from the trunk-root to the leaves and the fruit, (iii) the incorporation into the litterfall of the radionuclides in the leaves and fruit when they dry up and fall to the ground; (iv) the reincorporation into the soil, initially into its available fraction, of the radionuclides in the litterfall when this decomposes. The results obtained on applying this model confirm, firstly, that there exists a preferential uptake of strontium over caesium by the roots; secondly, that there is a greater transfer of caesium than of strontium within the plant; and lastly, that with the decomposition of the litterfall, the reincorporation of strontium into the soil is faster than that of caesium.

-69- CZ9827783

A SOIL- BASED MODEL TO PREDICT RADIONUCLIDE TRANSFER IN A SOIL- PLANT SYSTEM

M. Roig, M. Vidal, J. Tent and G. Rauret. Departament de Quimica Analilica. Universitat de Barcelona. Diagonal, 647, 08028 Barcelona, Spain. M. C. Roca and V. R. Vallejo. Departament de Biologia Vegetal. Universitat de Barcelona. Diagonal. 645, 08028 Barcelona, Spain.

Knowledge acquired from the Chernobyl accident has underscored the need to improve the quantification of parameters that affect radionuclide mobility, mainly radiocaesium and radios- trontium transfer through the food chain The multifactonal character of the transfer makes it dif- ficult to establish simple relationships between soil-plant attributes and transfer. Models based on the available fraction alone fail to predict the radionuclide mobility observed at field level, and predictions based on the calculation of the in situ KD appear to explain radionuclide behaviour better. However, the use of the available fraction is still needed to correct the value of the distri- bution coefficient.

The in situ Ku may be predicted from the values the sorption pool of the soils (mainly cation exchange capacity for radiostrontium, and specific sites in frayed edge sites in the illitic material for radiocaesium), and the levels of competitive species of the radionuclides. For radiocaesium, this means potassium and amonium levels in soil solution With respect to the available fraction, and if the desorption approach is used to quantify it, it is usually defined by the radionuclide fraction that may be desorbed by using an extractant reagent and that may undergo an exchangeable process in the solid phase, in given experimental condi- tions, often after a single extraction using a batch technique. However, to date there is no general agreement as to a common methodology for defining this fraction. The only agreement lies in the fact that monovalent cations seem to desorb radiocaesium exchangeable fraction better, whereas radiostrontium appears not to be so dependent of the reagent selected Therefore, a simple meth- odology, that may be applied in routine analysis, should be chosen to quantify this fraction The aim of this work was to check if the main soil parameters predefined as ruling soil-plant transfer were sufficient to predict a relative scale of radionuchde mobility in mineral soils Two agricultural soils, two radionuclides ( Sr and U4 Cs), and two crops (lettuce and pea) were used in these experiments following radioactive aerosol deposition simulating the conditions of a site some distance far away from the center of a nuclear accident, for which condensed deposition would be the more significant contribution.The available fraction of these radionuclides was esti- mated in these soils from experiments in which various reagents were tested and several experi- mental conditions were compared. As a general conclusion, the soil parameters seemed to be sufficient for prediction purposes, although the model should be improved through the consideration of physiological aspects, espe- cially those depending of the plant selectivity according to the composition of the soil solution.

-10- CZ9827784

MICROORGANISMS AS POTENTIAL VECTORS OF THE MIGRATION OF RADIONUCLIDES ?

Andres Yves SUBATECH UMR 6457 (Universite de Nantes, Ecole ties Mines, IN2P3.CNRS) 4, rue A. Kastler, B.P. 20722, 44307 Nantes Cedex 03, France

In the environment, the migration and the speciation of heavy metals and radionuclides depend on many factors such as the pH, the Eh and ... the microbiological life. Microorganisms (bacteria, yeast, fungi) have a direct action on the metal through biosorption, bioaccumulation or resistance/detoxification processes. On the other hand, they can influence the environment by producting mineral acids, chelating agents like siderophore, by-products of metabolism (organic acids...). The aims of our work are the study of the sorption of radionuclides by bacteria as the first step in the microorganism-metal interaction. The latter involves the fixation of ions on a surface layer and it results in the immobilization of the metal, thus possibly being the primary step of bioaccumulation. After a rapid presentation of the direct and indirect mechanisms of the interactions, we shall present our experiments of radionuclide biosorption by bacteria. A salient feature of biosorption is the selectivity of the adsorption of some radionuclides from a composed solution. For example, Andres et al. (1993, 1995) have shown that Mycobactehum smegmatis, from a composed solution containing uranium, thorium, , europium and , 4+ 2 3+ selectively adsorbs thorium ions. The sequence of preferential fixation is : Th > UO2 * > La = Eu3* = Yb3*. This selectivity is a function of the cell wall organization and of the speciation of the metal in the solution. Yet, each species of bacteria has characteristic and specific cell wall layer composition and organization. Moreover, the culture and the environmental conditions change the surface layer properties. Another parameter in the migration of radionuclides is the transfer from the soil to the microorganisms. In column experiments, Gd, and likely the rare earths, in general, adsorbed on sand can be removed with a suspension of bacteria (Thouand and Andres 1997). These examples will be discussed and serve as a basis to illustrate the diversity of the interactions beetwen microorganisms and radionuclides.

-71- CZ9827785

THE BIOACCUMULATION OF z10Po AND 210Pb IN THE SOUTHERN BALTIC ORGANISMS

Piotr Stepnowski1-2 and Bogdan Skwarzec1 Polish Academy of Sciences, Institute of Oceanology, ul Powstahcow Warszawy 55, 81-712 Sopot, Poland University of Gdansk, Faculty of Chemistry, ul. Sobieskiego IH 19, HO-952 Gdansk. Poland

Accumulation of polonium 2l0Po and radiolead 21uPb in three representatives (Saduria eniomon, Mya arenaria and Mylilus trossulus) of the benthic biota from the Baltic Sea was studied. Investigation into 2I0Po as well as in 210Pb content demonstrated that these radionuclides are not uniformly distributed in the studied organisms. The polonium content in the internal organs and tissues of the analysed organisms decrease in the following order: hepatopancreas > alimentary track > gills > hemoiymph > muscles. The same sequence was obtained for 2ll>Pb with the exception of hemoiymph which contributed up to 40% of the whole body 210Pb activity. The experiment showed that the values of the activity ratio 210Po/210Pb in analysed organisms were higher than 1. The lower values of this ratio was characteristic for muscles and hemoiymph. Highest values (close to 10) were found for hepatopancreas and alimentary track

-72- CZ9827786

PENETRATION OF RADIONUCLIDES ACROSS SKIN BARRIERS OF ANIMAL SKIN MODELS IN VITRO

V. Koprda, M. Harangozo, L. Boha&k, Z. Kassai Faculty of Chemical Technology, Slovak Technical University, Bratislava, Slovakia

The skin of animal species acts as a strong barrier against permeation of ionic forms of substances into an organism. In connection with radioactive contamination radionuclides of caesium, cobalt and actinides belong to frequent potential contaminants of human body Regarding the harmful effects of contaminating mixtures of radionuchdes adsorbed on the surface of the skin tissue two practical aspects must be considered: the absorbed energy of beta radiation in soft tissue, and the extent of amouts of penetrating radionuchdes causing internal contamination. In this paper: - the time dependence of permeation of [37Cs', 6uCo2', and 147PmJ< from aqueous solution through animal skin model has been studied, - the biologic structure mostly responsible for the barrier effect was selected and proved, - the relative importance of the mam diffusion pathways for l3'Cs', 60Co2* and "'Pm3' (the diffusion across the intact skin and the diffusion through the hair channels) was assessed. All experiments were done using radioactive tracers Experimental arrangement consisted of Franz-type vertical permeation cells used with fresh skin from abdominal region of 5 day old rats (SDR) of Wistar strain (Breeding Farm Dobra Voda, SK) and 9 day old rats (9DR), respectively SDR are still hairless, and 9DR are just short haired. The 5DR skin was used in full form (intact), and then with decreasing thickness of horny layer after the skin had been stripped with Scotch type (3M) 5-20 times respectively, or the skin was splitted under 60 °C hot water so that the whole epidermis was removed. Ions penetrated through the skin from donor solution (vehicle water) to receptor solution (phosphate buffered saline), were they were determined in aliquots sampled after 1,3,5,7 a 24 hours. Selected radionuclides were measured by means of Gama Automat, Tesla, SK. Permeated fractions and fluxes of donor solute were calculated regarding sampled amounts by home-made program PERMEA. It was found that the penetrated amounts of ions are proportional to the time at least in the first 7 hours. The permeation resistance of the skin is proportional to the thickness of the horny layer, the principal barrier mostly restricting the flux of ions. The results showed that the more is the skin stripped, the more enhanced is the penetration of ions It corroborates the fact that stratum corneum represents the most important barrier function of the whole skin (at least in the case of rats). Comparing amounts of penetrated ions through the skin without hairs (5DR) and through the skin with hairs, it was found that the additional diffusion through channels along hairs (follicules) can be of important value also in case of human skin where hair density is many times lower than in the case of the animal models used.

-73- CZ9827787

ARTIFICIAL RADIONUCLIDES IN OILS FROM THE UNDERGROUND NUCLEAR TEST SITE (PERM' REGION, RUSSIA)

Kalmykov St.N., Sapozhnikov Yu.A., Goloubov B.N. Division of Radiochemistry, Chemical Department, Lomonosov Moscow State University, Moscow 119899, Russia.

Underground nuclear tests (UNT) are one of the possible sources of radioactive contamination of environment. About 2500 UNTs were earned out both for military and industrial (peaceful) purposes. In the former Soviet Union most of peaceful UNTs were oriented to the needs of the gas- and oil-extracting industry. Earlier it was considered that the holes of UNT are hermetic and the leakage of radionuclides is negligible. In this work nine oil samples from Gezh oil deposit in Perm' region of Russia collected from different holes both where the explosion took part and from distant holes were analyzed for H-3, C-14 and such fission products as Sr-90, Cs-134,137 For the determination of y-emittmg radionuclides the y-spectrometry with HPGe detector was used For Sr-90 determination the measurements of Cherenkov radiation generated by daughter Y-90 were carried out with liquid scintillation equipment. It showed that even in the oil samples from the hole where the explosion took place no measurable Cs-134,137 and Sr-90 activities were detected. For H-3 and C-14 determination the oil samples were fractionated by distillation For each sample 10-12 fractions were taken. Liquid scintillation spectrometry was used for H-3 and C-14 simultaneous determination. It was shown that in all samples the H-3 and C-14 concentrations are higher than the background level and for the hole where the explosion took place reached the value of about 1,3-105 Bq/L for low boiling fraction (40-75°C). The H-3 and C-14 enrichment of oils from distant holes shows that UNT cavities are not hermetic and the radionuclide migration is not negligible

-74- Topic 2

RADIONUCLIOES IN THE ENVIRONMENT, RADIOECOLOGY

Poster presentations

-75- P2-1

ESTIMATION OF 226Ra AND ""K URINARY LEVEL IN CASE OF PEOPLE LIVING IN AGRICULTURAL ZONE

Luminita Albulescu1, Raluca Gheorghe1, Daniela Gruia1, Elena DSdulescu2 1. Institute of Public Health Bucharest 2. Inspectorate of Sanitary Police and Preventive Medicine Dolj

The urinary contamination with "6Ra and 4llK, as indicator of the exposure of the population with agricultural occupation, from the south of ROMANIA, in addition to the natural radioactivity due by the utilization as soil amendments or fertilizers, of the chemical phosphates products based on phosphates rocks and of the ashes resulted from the combustion of coal (in the thermo- electncal plant or in the individual housekeeping), has been studied. In the case of 226Ra, the set under study was constituted by 80 healthy persons from two rural zones and in case of '"K, by 120 healthy persons from three rural zones Every set had equal numbers of females and males, in the following age groups: children (7-8 years), puberts (13-14 years), adolescent (17-18 years) and adults (more than 25 years). The total daily urinary excretion of these subjects was collected the same day in the spring period of 1994 (for children of 7 to 9 years and 13 to 14 years, the total urinary excretion during 2 consecutive day was collected). Initially, the samples were wet ashed with nitric acid and hydrogen peroxide, the level of Ra- 226 was determined by specific radiochemical separation and the total alpha activity was measured using a low background counter, and the level of K-40 was determined by gamma spectrometry analysis. In the total set of persons, a mean daily urinary level of 0.096 Bq "6Ra/day with a variation between 0.059 and 0.149 Bq 2MRa/day and a mean daily urinary level of 28 Bq 40K/day with a variation between 15.37 and 45.68 Bq 40K/day were found.. The conclusions that can be drawn from these results concerning the distribution of these isotopes in the urinary daily excretion, its dependence on age or sex, are presented

-76- P2-2

INFLUENCE OF PHYSICO-CHEMICAL CHARACTERISTICS OF FRESHWATERS ON THEIR ARTIFICIAL RADIOACTIVITY CONTENT

A. Baeza(l), L.M. del Rfo(l), A. Jiménez(l), D. Cancio(2) (1) Dpto. de Fisica, Facultadde VeterinariayEscuela Politécnica, Universidadde Extremadura, Avda. de la Universidads/n 10071 - Câceres (Spain). (2) Institute de Medio Ambiente, Centro de Investigaciones Energéticas, Medioambientales y Tecnolôgicas, Avda. de la Complutense 22, 28040 - Madrid (Spain).

Considering fifteen aquifers of the Autonomous Community of Extremadura, which is situated in western Spain on the frontier with Portugal, we determined the activity levels of the following radionuclides in solution: 3H, ""Sr, 134137Cs, and ^w^uo^ Simultaneously, we quantified the concentrations of the ions Ca, Mg, K, Fe, and NH4, together with the values of the pH, conductivity, dry residue, and the subterranean or surface ongin of these waters. The activity levels detected for each of the radionuclides mentioned above were of the order of those normally reported in the literature. Specifically, all the values obtained were less than: 327 Bq/I for 3H, 21.3 niBq/I for '"Sr, 0.28 mBq/1 for 134Cs, 1.23 mBqfl for 137Cs, 4.4 mBq/1 for 238Pu, and 13.8 mBq/1 for ^^Pu. We were able to establish statistically significant linear correlations between the levels detected 137 239+240 in the waters for '"Sr with those for Cs and pu This seems to indicate the common origin of at least a great part of the activity detected for the aforementioned radionuclides, the worldwide radioactive fallout produced by the atmospheric nuclear tests. However, the surface waters analyzed belonging to the cooling reservoir of the Almaraz nuclear power plant do not satisfy the above correlations, with levels of activity above those normally measured in other aquifers for the radionuclides 3H, 1341"Cs and ^Pu. We found the waters analyzed from a surface origin to have mean radioactive contents of the cited man-made radionuclides which are greater than those existing in waters of subterranean origin In fact, the greater presence of dissolved iron in the surface waters and their slightly acidic 239 240 character favour the presence of '"Sr and * pu in solution Also increased pH or mineralization of the waters - as measured by the conductivity or by the calcium- concentration - leads to a decrease in the 23B*24l)Pu/i>0Sr isotopic activity ratio Respecting the mean value detected for A(137Cs)/A(91)Sr) in solution, (0.10±0.07(SD)), it has to be noted that it is far below that existing in the surface layers of the soils of the region, the value for which is (1.7±1.0(SD)). This is coherent with the greater mobility that strontium normally exhibits in soils as compared to caesium, and consequently with the greater difficulty with which the latter is being dissolved in waters

-77- P2-3

APPLICATION OF PULSE DECAY DISCRIMINATION LIQUID SCINTILLATION COUNTING FOR INDOOR RADON MEASUREMENT

H. Bern1, E. M. Bern2, M. Ostrowska1 'institute of Applied Radiation Chemistry, Technical University of Lodz, Zwirki 36, 90 - 924 Lodz, Poland 2Department of Environmental Engineering, Technical University of Lodz, Wolczanska 175, 90 - 924 Lodz, Poland

Among many methods developed for indoor radon measurement the method, which uses plastic liquid scintillation vials with active charcoal adsorbent (Pico Rad detectors) proved to be useful for a large scale surveillance In this method the average radon concentration in the ambient air during usually 2 days exposition of the open vials is calculated by a special computer software after elution of Rn to liquid scintillation solution and counting of the total alpha and beta activities in the fixed channel Application of pulse - decay discrimination technique (PDD) available in the modern liquid scintillation counters allows on separate counting of alpha and beta decays with relatively low (ca. 1 cpm) background in the alpha memory By the proper choice of the scintillation solution (with addition of liquid naphthalene derivatives) and PDD settings in the counter, one can obtain very low misclassification (< 5%) of beta pulses as alpha events, whereas the detection efficiency can still be almost 100% Practical comparison of the classical counting of eluted Rn with PDD method (row # 4) is given in the table.

No. Channel Background Figure of Detection Determination mernt limit [Bq/m3l limit [BqWl 1 100-850 34.0 0.252 1.7 57 2 250 - 850 23.2 0.290 1.5 5 1 3 550-850 86 0370 1.2 44 4 550 - 850.•. 50 0388 1.1 4.4

Figure of mernt was calculated as K/BU5, where K - was the corrected activity in cpm corresponding to Rn concentration equal to 1 Bq/m3 and B - background in cpm In the PDD mode to the eluting xylene based scintillator 20 % v/v of Ultima - Gold scintillator was added As it is evident from the table the slight improvement in terms of detection limit and figure of mernt for PDD mode was achieved and it can be important for measurements of low indoor Rn levels. This method has been successfully applied by us for indoor Rn measurement in 31 kindergartens in Lodz area of Poland, where Rn levels were rather low. The arithmetic mean of indoor Rn concentrations for kindergartens was 11,4 Bq/m3 with standard deviations 8.3 Bq/m3 Corresponding geometric mean was 9 5 Bq/m3 with GSD equal to 1.8. Minimum and maximum values of measured concentrations were 3,7 and 38.5 Bq/m3, respectively.

-78- P2-4

COMPLEXATION PROPERTIES OF THE SIDEROPHORE PYOVERDINE 4 2+ 4 A TOWARDS DIFFERENT CATIONS : U *, UO2 , Th * AND OTHERS; A COMPARATIVE STUDY

M. Bouby, I. Billard and J. MacCordick IReS, CNRS/IN2P3- ULP, Chimie Nucleaire, Bat. 35, B.P. 28, 67037 Strasbourg Cedex 02, France.

In order to predict the long term stability at nuclear repository sites, further knowledge of the possible physical, chemical and biological interactions is necessary. Studies were therefore carried out on the complexation of cations of interest by the siderophore Pyoverdine A, a molecule extracted from the widespread bacterium Pseudomonas aeruginosa. Siderophores are synthesized by the bacteria to solubilize and transport iron (III) ions within the cell, but various studies have shown that others cations can also be complexed. New results are summarized here that compare the complexation of the cations U4\ Na' and 2 4 N(CH3)/ with reactions previously reported for UO2 *and Th * with this siderophore. In each case, we have determined the stability constants with appropriate models that take into account the effect of both ionic strength and possible hydrolysis of the cation. The number of protons liberated in the complexation process has been determined, and a general trend has been established for pyoverdine. These experiments and results have enabled comparisons that provided evidence for selective action toward cations of various states of oxidation.

-79- P2-5

THE INVESTIGATION OF URANIUM CONTENT IN HOKUTO HOT SPRING WATER

Cheng-Hsien Hsieh1, Chin-Wang Huang2 ' St. John's & St. Mary's Institute of Technology Tamsui, Taipei, Taiwan, 251, ROC 2 Chung Yuan Christian University, Chung Li, Taiwan, 320, ROC

Hokutolite is one of the precious minerals found in Taiwan. It is found in the Hokuto valley. The hot spring water in Hokuto contains high concentration of uranium, it has low pH (approx. pH = 1.5) and high temperature. I have been gathering about 20 litres of hot spring water from this area once a week for about a year, and I know the relationship between hot spring water, the geology and the nature environment. We separate uranium from the water by Chelate Resin method. We then use Arsenazo III Spectrophotometric method, subjecting uranium to 665 nm wavelength absorption measurement. ICP-MS and a-ray spectrometry of the hot spring water was also performed. The average concentration of uranium is about 5 ppb. According to our experience from long-term investigation, uranium concentration is season, temperature and rainfall intensity dependent. The uranium amount may also increase due to earthquake vibrations. P2-6

CALIBRATION OF Nal(TI) SPECTROMETER FOR RADIOCESIUM VOLUME -SAMPLES. SOME RESULTS FROM TRANSYLVANIA REGION

C. Cosma, L. Daraban, D. Ristoiu, L.Nagy Faculty of Physics, University "Babes-Bolyai" 3400 Cluj-Napoca, Romania

After the Chernobyl accident a large diversity of l37Cs deposits was observed in different countries. In Romania the greatest deposit was on NE-SW direction, some of these being higher than 20 kB/m2 [1] The absence of volume-standards in the immediate subsequent period of imposed the necessity of utilisation of lj7Cs point sources in some laboratories for the calibration of measuring devices [2] A NP-424 type of four channels gamma analyser coupled with a large Nal(Tl) scintillator was calibrated using a "7Cs point source. The volume-samples were plexiglas (PMMA) cylindrical boxes (D = 76mm, H = 40mm) directly placed on Nal(Tl) detector. Measurements for 64 indoor positions at full-662 keV-peak were made. Sample selfabsorbtion was determined considering a linear attenuation for gamma radiation and measuring the absorption factor for maximum thickness of the volume-sample (h0 = 40mm). A direct and a semiempirical model of calculus [3] were used. The obtained results for two types of environmental samples (soil and milk-powder) are compared with the data acquired from other Romanian laboratories in the programme of the Environmental Radioactivity Seminar which standardised such types of measurements. The same samples were measured at Louvain la Neuve (Inorganic and Nuclear Chemistry Laboratory) and the results were in good agreement with our measurements. The paper also presents some measurements of radiocesium deposits in Transylvania region obtained using the Nal(Tl) spectrometer calibrated by this method. These results show that a large deposit exist on the direction NE-SW in connection with radioactive cloud passing by

References

[1] C. Cosma, M Salagean, A Pantelica, Studia Univ."Babes-Bolyai",Physica, 33, 65 (1988) [2] 1 Chereji, J Radioanal.Nucl.Chem Lett., 165, 305 (1992) [3] M Korun, R Martincic, Appl.Radiat Isot. 43, 29 (1992)

-81- P2-7

SCIENTIFIC BASIS FOR DECONTAMINATION OF SOIL CONTAMINATED AS A RESULT OF THE CHERNOBYL ACCIDENT

Davydov Yu.P., Westrich H. R., Toropov I.G., Vasylevskaya T.V.,Voronik N.I.,Toropova V.I.

The Chernobyl accident has caused a wide scale contamination of rural and urban lands with radionuclides. At present the rehabilitation of the contaminated territories is considered to be one of the most important problems. The rehabilitation problem arises a number of questions which need a complex approach to be solved. The decontamination and especially soil decontamination questions seem to be the most important and the most complicated ones. In our opinion the soil decontamination technology can be developed only on the basis of deep scientific investigation of the radionuclide state in the soil and soil solution, sorption-desorption behaviour of the radionuclide, effect of the soil composition on physico-chemical behaviour of radionuclides. In this work some approaches, described in the literature, for the investigation of the state of radionuclides in soil and soil solution were analysed and the way of soil decontamination proposed. The latter consists of hydroseparation of the fine silty fraction, which may include up to 95% of Cs radionuchdes according to the field investigation, from the bulk ammount of the soil and its consequent chemical treatment for Cs removal from the silty particles of soil and its reconcentration. The chemical treatment is necessary in order to reduce the volume of waste for disposal and to return the fertile part of the soil (fine silty fraction) in agricultural use. The composition of solution has been found that may extract more than 90% from the silty fraction The extraction in this solution takes rather a long time and further kinetic study is necessary in order to make use of it in practice.

-82- P2-8

STUDY OF FALLOUTS OF "NON-VOLATILE" RADIONUCLIDES IN SOUTHERN BELARUS AFTER CHERNOBYL NPP ACCIDENT

Yurij V. Dubina, Larisa N. Guskina, Stanislava B. Kulich Institute of Radioecological Problems / National Academy of Sciences of Belarus

Elaborate gamma-spectrometric measurements of soil samples collected during the last years were executed at the Institute of Nuclear Power Ingineering / Academy of Sciences of Belarus in 1986. Basing on these measurements, the fallouts of 95Zr, 141Ce, 144Ce and their daughter isotopes in the districts of Bragin, Hojniki and Narovlia in the Gomel region was de- termined. For this purpose, more than 2300 verified measurements of soil sampled in 276 set- tlements of these districts were performed. A statistical analysis of the specific activity of these radionuclides and their relation to the ac- tivity of caesium isotopes in the soil samples was carried out. The nuclide ratios 137Cs/141Ce or 134Cs/95Zr showed wide and partly unexpected variations. The contribution of "non-volatile" isotopes to the total activity was distinguished and two-dimensional spatial distributions of their fallouts were constructed using average values over several samplings for each settlement For the considered districts the high relative contents of "non-volatile" radionuclides is a distinction. For example, the contribution of 141Ce to the total activity exceeded 10 % in a greater part of the samples of May 15, 1986 The distribution of fallout of these radionuclides was highly uneven. The highest specific activities observed were 23000 kBq/m2 of 141Ce and 26000 kBq/nr of 95Zr in the south-western Bragin district.

-83- P2-9

DETERMINATION OF 226RA AND 228RA IN MINERAL AND TAP WATERS BY USING 3MS EMPORE™ RADIUM RAD DISKS

A.Durecova, F.Durec Specialized Stale Insiiliiie of Public Health, Radiation Protection Department, Vesta k nemocnwi I, 9r5 56 Banska Bystrica,Slovakia

Various type of mineral and tap waters have been tested tor the simultaneous determination of 22"Ra and 22SRa by using 3Ms EMPORE"'Radium Rad Disks Radionuclides "6Ra and 228Ra were measured in the form of their daughter products. J2('Ra by conventional radon emanation techniques and 228Ra as its daughter ~~sAc by using proportional counter. 0.2 M diammonium hydrogen citrate adjusted by ammonia to pH = 7.8 was used for radium elution from the disk and 0.0003 M diammonium hydrogen citrate was used for actinium elution from the disk.

-84- P2-10

STUDY ON NUCLEAR ACTIVITIES BY THE MEASUREMENT OF RESIDUAL RADIOACTIVITY

T. Elnimr, T. Sharshar and A. El-Abd HaJioanalysis Research laboratory, Physics Department, Tania University, I'anta, EGYPT

Radioactive caesium-137, caesium-134, cobalt-60 and some other radioisotopes were introduced into atmosphere as a result of nuclear activities such as nuclear test explosions and the failure of the nuclear power plant as well as to the leakage of the radioactive waste In fact test explosions took place in various areas of the world mostly in the fifties and the sixties. It can be assumed that the resulting total fallout of Cs-137 into the earth surface has been almost uniform even within large regions. On the contrary the fallout resulting from the single power plant accident or nuclear test explosions differed greatly as it depended on the migration of the radioactive cloud in the subsequent days after the nuclear accident and occurrence of rainfalls or aerosols fall-out introducing the radioisotopes directly onto the earth surface Part from our results of the our research programme in the radioanalysis research laboratory, for environmental radioactive contamination studies are presented 300 samples of foodstuffs, soil, water and fertiliser were analysed for Cs-137, Cs-134, Co-60 and K-40 using single y-f&y spectrometer employing 10% HPGe detector and the new Compton suppression spectrometer. Large difference in Cs-137 and Co-60, could be detected by biomomtor The results gave us clear information about the nuclear activities somewhere.

-85- P2-1I

LEAD-210 AND CAESIUM-137 AS MARKS FOR STUDYING THE WASHOFF AND ACCUMULATION PROCESSES

V.N.Golosov1, E.V.Kvasnikova2, E.D.Stutin2, D.Walling3 'Moscow State University M. V.Lomonosov 2Institute of Global Climate and Ecology, Russia 3 University of Exeter, Department of Geography, UK

The comparison of the vertical distribution of the natural radionuclide lead-210 (21uPb) and the artificial radionuclide caesmm-137 (l3'Cs) in the soil of the areas with the intensive processes of denudation-accumulation is necessary to study redistribution of the sediments. 210Pb and [37Cs are of the same period of half-life - about 30 years. The results of the gamma-spectrometric analyses (with the X-ray spectrometry) of the soil samples taken layers by layer are shown in Fig. 1 and Fig.2.

Sample 20. Pb-210 Sample 20. Cs-137 2500 I 2000 • - —

, IS00 i I 1 1000

Fig. 1. 21"Pb vertical distribution Fig. 2. Cs vertical distribution

This sample was taken in June 1997 in the accumulative geosystem of the valley bottom. ls7Cs maximum corresponds to the season of spring-summer 1986 The upper 7 cm layer is the soil transported here after summer 1986 The decrease in the 210Pb content with depth shows the simultaneous processes of the radioactive decay of this radionuclide and of the temporary income of this radionuclide by the processes of the soil accumulation Each of these radionuclides presents important information for the geomorphological study Studying the vertical distribution of 137Cs and 210Pb presents two independent ways to estimate the erosion processes. 2l0Pb distribution in the soils of accumulative landscapes enables to investigate a time period of soil resedimentation within 100-110 years; that one of 137Cs within somewhat shorter, but also considerable period of time. P2-12

LEVELS OF RA-226 PRESENT IN WATER SOURCES OF HAVANA CITY, CUBA.

Isis Maria Fernandez G6mez, Miguel Prendes Alonso, Niury Martinez Ricardo Center for Radiation Protection and Hygiene

The control of the concentrations of Ra-226 in water for human consumption became a practice in various countries. The reason is that concentrations of Ra-226 in groundwater may be significant, because of the good solubility of radium compounds in the earth core. In this work water samples from 21 sources of Havana City, Cuba, were analysed The concentrations of Ra-226 were determined by emanation of Rn-222. The minimum detection limit for the method used was 3 mBq/L. The results showed that Ra-226 concentrations in waters under study are in the range of 24 - 175 mBq/L. These concentrations correspond with the values reported in the literature for water sources in other countries. In any case, they do not exceed the level required by the Cuban standard for potable waters (1 Bq/L).

-87- P2-13

INDOOR RADON CONCENTRATIONS IN HOSPITALS

S. Gozubuyuk, G. Yener, S.F. Erees Ege University, Institute of Nuclear Sciences, 35100 Horuovu, Izmir, 'turkey

Exposure to radon and its decay products is accepted as the primary component of human irradiation by natural sources. The most important mechanism of exposure is the inhalation of short lived radon progeny with indoor air. In the present work a survey of 222Rn concentrations in ten hospitals in Izmir, the largest city of western Turkey, was carried out for two years Lucas cells were used for radon measurements. Gamma doses were also measured with micro R-meter Measurements were performed at different floors of the buildings within the heavy working hours of the personnel The total annual effective doses were estimated P2-14

AN INVESTIGATION OF ACTIVITY OF RADON CONTAINING IN HOT SPRING WATER IN TAIWAN

Guo-Chung Dong, Chin-Wang Huang Department of Chemistry, Chung Yuan Christian University, Republic of China

Radon is one of the radioactive nuclides in natural environment Generally, it is gaseous in nature. After further investigations, it has been suspected to hurt human health, especially causing lung cancer to miners. Therefore, it is important to investigate the distribution of the radon in our environment. Recently, radon was well known as a sensitive element to predict earthquake. In order to understand Rn-222 containing in hot spring water in Taiwan, we collected water samples from 23 sites of hot spring water in Taiwan. In past decades, radon in water was always determined by Liquid Scintillation Counter (LSC) method However, the results were usually influenced with sampling process and pretreatment. Therefore, we control all experiment procedures in seal and isothermal condition well. It is expected to get results correctly, simply and conveniently.

-89- P2-15

PREDICTION OF IMPACTS OF TEMEUN NPP ON HYDROSPHERE

E. J. llanslik T. G. Masaryk Water Research Institute, Prague

The beginning of the construction of the Temelin Nuclear Power Plant (NPP) dates back to 1986, however, its finalization was approved by the Czech Government in March 1993. Of the originally planned four pressurized water reactors of the WWER 1000 type, only two will be completed, as was decided after making more accurate estimates of future electricity demands in the Czech Republic. Since its establishment, the Ministry of the Environment has paid an attention to problems associated with the NPP, and it has been responsible for carrying out a project on Impact of the Temelin NPP on the hydrosphere, funded from the national budget. In 1996, methods, applied in carrying out the project, were examined and recommended by the International Atomic Energy Agency in Vienna, within the framework of its technical assistance organized in cooperation with the Ministry of the Environment of the CR and the State Office for Nuclear Safety. The objective of the project was to ensure professional measurement and compilation of all data necessary for examination of a reference state of the environment (state describing conditions and their changes before setting the NPP into operation) in terms of parameters indicating radioactive and non-radioactive pollution and other characteristics of the environment. It was also intended to establish a wider and independent observation compared to that carried out by the Environmental Survey Laboratory of Temelin NPP. The research was also focused on the prediction of the impact of the effluent returns from the NPP on water quality in the Vltava River at Prague, where water is used for drinking water supply purposes, in the Elbe River at Hfensko, Czech-Germany boundary site, and an attention was also paid to groundwater quality in wider environs of the NPP. Possible impacts were studied for conditions of the normal operation and for a case of an accidental contamination. The project proceeds with the main attention paid to an examination of dynamics of change in parameters of the hydrosphere and to the assessment of possible impacts of new factors - the nuclear fuel and security systems of the Westinghouse company now installed in the NPP - on the environment under the asumption of the maximum project accident.

-90- P2-16

MELANOIDINES AS MODEL HUMIC ACIDS IN RADIOECOLOGICAL RESEARCH

K.H. Heise *, R. Nicolai", S. Pompe \ M. Bubner", H. Nitschea Forschungszentrum Rossendorfe. V., " Institute of Radiochemistry, hInstitute of Bioinorganic andRadiophartnaceutical Chemistry, P.O. Box 510119, D-01314 Dresden, Germany

Natural humic acids are not a well defined system in the sense of chemical compound. Therefore, their physical-chemical properties may never be exactly described. Results of environmental investigations of the interaction between humic acids and heavy metals, including uranium and other actinide elements, are often uncertain From this feature the demand for stable and well characterized humic acid model compounds for systematic studies of interaction processes has been repeated over and over again1. We have separated humic acid like fractions from melanoidmes2. These substances have good chemical stability. It is possible to design the functionality of these melaniodines by varying of their precursor substances and the conditions of their chemical synthesis Furthermore, we have compared different melanoidines and their interaction with UO22* with the behavior of natural humic acid from Aldrich by infrared spectroscopy (FTIR). These investigations reveal many functional similarities between the melanoidines and the natural humic acid. Comparable symmetric deformation vibrations of uranium in the far infrared range (FIR) indicate similar uranium coordination. In the middle infrared range (MIR), the antisymmetric stretching vibrations of the uranium bond are nearly identical. In connection with other investigations3 we have shown, that the melanoidines fulfill all demands on a humic acid model substance for fundamental radioecological research.

1 B.S Jensen, T. Halken, I. Jestin, D. Jergensen: The Role of Colloids in the Migration of Radioelements., Final Report EUR 16763 EN (1996)

L.-C. Maillard: Synthese de Matieres Humique par Action des Acides Amines sur les Sucres Reducteurs. Ann Chim. (Paris) 5, 258-317 (1916)

3 S Pompe, M Bubner, M. Denecke, T Reich, A. Brachmann, G. Geipel, R Nicolai, K.H.Heise, H. Nitsche: A Comparison of Natural Humic Acids with Synthetic Humic Acid Model Substances: Characterization and Interaction with Uranium (VI) Radiochim Acta 74, 135-140(1996)

-91- P2-I7

MONITORING OF RELEASES OF 238Pu,239 240Pu, 241Am, 242Cm AND 244Cm IN GASEOUS EFFLUENTS OF V-3 AND V-4 NUCLEAR POWER PLANTS AT DUKOVANY IN THE CZECH REPUBLIC IN 1994,1995, 1996 and 1997

Holgye Z., Filgas R. National Radiation Protection Institute, Prague, ('zech Republic

23 m > 241 242 !4J The activity concentrations of *Pu, '* pu, Am, Cm and Cm and the discharged activities of these radionuclides in airborne effluents of V-3 and V-4 nuclear power plants (each consists of two WWER-440 reactors) were determined. In the case of V-4 the activity concentrations of individual radionuclides in airborne effluents in 1994, 1995 and 1996 were very low (< 0.10 mBq.m°) and the annual discharges of individual radionuclides were less than 100 Bq. Similar data were found in case of V-3 nuclear power plant in 1994 and 1995 In 1996, however, increased concentrations of transuranium elements in airborne effluents were observed 238 24lu 9 241 242 as a result of a defect in the fuel cladding. The annual discharges of Pu, -' Puj Am, Cm and 244Cm were 3430, 1770, 1000, 18630 and 1210 Bq, respectively. Variations of the present discharge data with time and of those obtained previously at the nuclear power plants under study and at the nuclear power plants V-l and V-2 (J.Bohunice, Slovak Republic), activity ratios of radionuclides in discharged gases and other related topics are presented and discussed.

-92- P2-18

RADIONUCLIDES COMPOSITION AND PARAMAGNETISM OF SOILS OF THE SNTS

I.V. Kazachevskiy, S.P. Pivovarov, V.P. Solodukhin, Kh. Sirajet, C.N. Chumikov, S.N. Lukashenko, A.B. Rukhin, T.A. Seredavina. Institute of Nuclear Physics, National Nuclear Centre, Republic of Kazakstan

It is well-known that wide-scale tests of nuclear weapons at the Semipalatmsk Nuclear Test Site (SNTS) had led to serious contamination of the environment by radionuclides To ascertain a level of ecological danger it is necessary to study their bonding in environmental media. Therefore a complex investigation of radionuclides composition and paramagnetism of soils of the test site was undertaken. Both whole soil samples and their different fractions were analyzed at several locations of the SNTS. Gamma-emitting isotopes Co-60, Cs-137, Eu-152, Eu-154, Am-241 were determined with gamma spectroscopy. After radiochemical separation Pu-239 + Pu-240, Pu-238, Am-241 and Sr-90 (on Y-90) were determined using alpha- and beta-spectroscopy Results of determinations show considerable differences in concentrations and ratios of radionuclides for different samples and fractions of soil. The most interesting fact discovered is the association of trans-uranium elements with magnetic soil fraction for some locations of the SNTS For separate locations the magnetic fraction contains practically all americium and more than a half of plutonium, although, at the same time, its content of caesium-137 is insignificant. The investigation of leaching of radionuclides with the help of acidic solutions (boiling 7M HNOj, for 2 hours) showed that, for non-magnetic fraction, less than 0,1 per cent of transuranium elements passes into solution. Simultaneously EPR-spectra of the same samples were investigated. Practically, in all the samples four types of signals can be clearly distinguished: - the signal of ferromagnetic resonance with line width from 0 215 T to 0.08 T - the signal with g-factor of 4.3 of paramagnetic He3' in high-symmetric surroundings; - the signal with g-factor of 2 0 caused, most probably, by iron being in the complex of low symmetry; and - the narrow signal with g-factor of 2.007 connected with radiogeneous centres in silica. The intensity and width of lines of these signals significantly change from sample to sample For a set of events there is observed also a visible anisotropy of g-factor Nature of observed effects and correlations between the content of radionuchdes of different types and intensities of EPR-signals are discussed.

-93- P2-19

THE COMPLEX-FORMING AND SORPTION PROCESSES OF TRANSURANIUM ELEMENTS IN THE DIFFERENT SOIL TYPES S.L.Kiltchitskaya, G.A.Sokolik, T.G.Ivanova, S.L.Leinova, I.M.Kimlenko, N.V.Zhukovich, V.V.Duksina Belarussian State University, Laboratory of Radiochemistry, Minsk

There is a potential possibility of transuranium elements entering the environment during the production, use and processing of nuclear fuel. In particular, the Chernobyl NPP incident caused considerable contamination of the southern region of Belarus by long-lived transuranium ele- ments. Their contribution to the internal irradiation dose will increase with time owing to 24lAm accumulation and increasing quantities of biologically accessible forms of 239F240PU and 241Am. The investigations have shown that soil is a powerful geochemical barrier for the migration of transuranium elements in different food chains. The aim of this work was to investigate the com- plex-forming and sorption mechanisms of 239'240Pu and 241Am by absorbing complexes in soil and to reveal the main factors influencing the solubility of transuranium elements and their migration capability. The use of natural soil samples when studying complex-forming mechanisms and sorp- tion is difficult as the investigated objects are very heterogeneous. In this connection, model media with known physico-chemical parameters (hutnic and fuivic acids, silicate minerals, ion-exchange resins) imitating the main components of soil sorption complexes were used. By means of modern methods of investigation (a-spectrometry, gel-chromatography, different methods of selective extraction, radiochemical analysis), the following was investigated: the sorp- 239240 241 tion isotherms of pu and Am by ion-exchange resins from solutions in presence of differ- 23924 241 ent complex-forming agents, the processes of VU and Am sorption-desorption by humic acids and silicate rocks; the influence of molecular masses of organic ligands on the stability of 239,240pu an(j 241^^ comp]exeS; the interphase distribution of transuranium elements in the system «soil solution - solid phase» in dependence on the degree of oxidation and the concentration of radionuclides; the capability of the mineral part of soil to sorb the fulvic and humic complex- B9 240 241 forming compounds, the main factors that cause the migration capability of - pu and Am in «soil-plant» systems. Revealed peculiarities allow to estimate the influence of the soil solution content, the mineral part of the soil complex, the molecular mass content of soil humus and other factors on physico- chemical state of the tranuranium elements in different soil varieties and to develop the methods of decreasing the biological accessibility of radioecologically dangerous contaminators

-94- P2-20

RADIOACTIVITY OF MINERAL WATERS IN BOHEMIA

Zdena Krejbichova AQUATESTSGa.s., Geologickd 4, PrahaS, 152 00

Mineral and thermal waters are a special kind of ground-water distinguished by specific chemical and physical properties as higher mineralization, trace elements, dissolved gases or higher temperature or radioactivity. A large part of mineral and thermal waters in Bohemia is a part of a great European province of carbonated waters, which extends from France over Eiffel, Rhon, Harz to the Western and North Bohemia and to Silesia. The valuable mineral waters appear in Middle and Eastern Bohemia and in Moravia. The greatest accumulation of rich mineral and thermal springs and of famous spas is in a relatively small area in NW corner of Bohemia - the biggest Czech spa Karlovy Vary with hot springs - Jachymov related to discovery of Po and Ra with Radon bath - Frantiskovy LaznS and Marianske Lazne with cold springs, farther Kyselka, Kynzvart, Teplice up to Vratislavice in N Bohemia. The first ,,chemical" description of hot springs in Karlovy Vary dates to 1552 (Vaclav Payne). The authors of chemical analyses of these waters in a modern way of understanding were D. Becher (1770), later Klaproth and J. Berzelius. The measurements of radon content in our mineral waters have a long history, too - in 1905 H. Mache, S. Meyer published the article ,,Uber die Radioaktivitat osterreichisher Thermen". It concerns Rn in Karlovy Vary, Marianske Lazne, Frantiskovy Lazne, Jachymov, ... Gastein, Voslau, Piesfany. . J. Step initiated the first primitive radon bath in Jachymov in 1906. Numerous Rn data were published by F BShounek, Santholzer, Manila, V. Majer and others in the period between the two world wars. The laboratory of Jachymov Spa controls Rn-therma since 1920, systematically since 1924. The studies of mineral springs have been conducted in Czechoslovakia for a long time The company Aquatest - Stavebni geologie took part in these activities since early 1960s - new capture of springs, investigation boreholes, proposition of protective zones. Search of new mineral resources pass contemporary. The results of radiochemical analyses (Ra, U, Rn, etc.) of AQ are presented in tables in the poster. Survey of historical data and of analyses of other institutes is listed comparatively Some notes are devoted to the age and the origin of waters. The parallels with some foreign mineral sources are mentioned.

-95- P2-21

PECULIARITIES OF RELATIONSHIP BETWEEN RADIOACTIVE CAESIUM AND STABLE POTASSIUM IN AQUATIC ECOSYSTEMS

Kudelsky A.V., Pashkevich V.I., Ovsiannikova S.V., Petrovich A.A. The Institute of Geological Sciences of the National Academy of Sciences of Belarus, Minsk

The ability of radioactive isotopes of caesium to redistribution due to water migration depends not only on the level of radioactive contamination of water bodies, but on the physico-chemical conditions existing in the aquatic ecosystem. One of the most important characteristics of water medium which defines the behaviour of radiocaesium is the content of water-soluble form of stable potassium in the system. The present work is devoted to the analysis of behaviour of radioactive caesium and stable potassium in underground, lake, opened bog waters, in the soil solutions as well as in the systems "soil water - plant", "lake water - biota" and "lake - fish" The observation sites are situated in the south and south-east of Belarus at a distance of 25-240 km from the Chernobyl nuclear power plant. These territories of Belarus were contaminated as a result of the Chernobyl catastrophe in 1986. It was established that there is an obvions relationships between the content of radiocaesium and stable potassium in the water whatever the aquatic ecosystem type was. The degree of correlation is very high (respective coefficients of correlations R=0.9-1.0). But the type of relations between two chemical analogous depends essentially on the ecosystem variety. One of the possible reasons of such a behaviour is a different composition of natural waters (pH, level of mineralisation, cationic and anionic composition, fulvic acids content, etc.). It is also very important what kind of solid matter interacts with natural water and controls over the sorption- desorption processes at the surface of solid phases. It was shown that in the systems including biological objects the behaviour of radiocaesium and stable potassium depends on the biochemical role of potassium in the living organism.

-96- P2-22

CAESIUM-137 BEHAVIOUR IN SMALL AGRICULTURAL CATCHMENT ON THE AREA OF THE CHERNOBYL CONTAMINATION

E.V.Kvasnikova, E.D.Stukin, O.V.Glushko Institute of Global Climate and Ecology, Russia

V.N.Golosov, N.N.Ivanova, A.V.Panin Moscow State University M.V.Lomonosov, Department of Geography, Russia

The Chernobyl NPP accident of 26 April 1986 resulted in generation of radioactive terrain contamination field in Europe, mainly by the long-lived artifical radionuclide caesium-137. The area of European territory with caesium-137 contamination levels above 40 kBq/m2 is 240,3 thousand km2, it consists about 2 per cent of the total area of the continent. This area is cover by the agricultural lands, forests and localities. So, the study of the caesium-137 behaviour is very urgent to estimate doses. Let us note that within the territories with the contamination levels above 40 kBq/m2 averaged effective equivalent radiation dose of the population can reach 1 mSv, and within the territories with the levels above 555 kBq/m2 it can reach 5 mSv. These levels can affect health of the population living on these areas. This study is devoted to certain aspects of experimental investigations of l37Cs contamination variations in attended landscapes taking into consideration processes of soil erosion and accumulation of the soil particles m accumulative geosystems, and investigations of vertical distribution of this radionuclide in the soil during the period after its deposition. Conclusions obtained are based on the field studies within a catchment of the Lokna-nver (Tula district, Russia), supported by grant INTAS-RFBR N 95-0734. Experimental field observations were carried-out in the centre of Plavsk caesium pattern characterised by the mean contamination levels of 150-800 kflqm2. The studied territory consists of catchments of the balkas falling into the Lokna-river. The attended landscapes of the balkas and adjacent interfluves (ploughed practically everywhere) were investigated The analysis showed that the soil layer of 0-20 cm containes above 90 per cent (namely, 92-98 per cent) of 137Cs stored in the natural facies of the balka bottom. So, we can say that a decade after the accident, even under the conditions of erosion-accumulation at the balkas bottoms under natural meadow vegetation formed on loamy chernozem-type soils, the soil layer of 0-20 cm provides rather complete characteristics of this radionuclide stored. At the bottom of the balka the total increase in B7Cs stored in the layer of 5-10 cm is detected (this layer contains 30-50 per cent of the total li7Cs stored) The upper layer (0-5 cm) is relatively poor in caesium, it contains only 25-30 per cent of the total 137Cs stored. This distribution is connected with "bunng" of the initial upper layers of 1986 deposition under the sediments from arable interfluves. The results of the analysis on 137Cs content in layer-by-layer samples taken in typical natural landscapes show that '37Cs vertical migration is of common exponential character. The upper 5 cm layer from the forest sample containes above 80 per cent of Cs-137, and that from the meadow sample - in the upper 10 cm layer (88 per cent). Some samples from the mtertluves contained sub-arable layer (30-40 cm) in addition to the layer of 0-30 cm covering the whole ploughung depth. Let us note that this layer (30-40 cm) containes less than 5.5 per cent of the total Cs-137 stored. So, one can make a conclusion that 30 cm layer provided in 1996 sufficiently reliable and complete characteristics of the storage of this radionuclide in the soils of Central Russian Upland.

-97- P2-23

PHASE BEHAVIOR OF Eu(lll) IN FULVIC ACID -Fe(lll) -H2O SYSTEM AT pH 1-9

E. K. Legin, Yu. I. Trifonov, M. L. Khokhlov, and D. N. Suglobov Khlopin Radium Institute, Research and Production Association, St. Petersburg, Russia

Among diverse specific and nonspecific compounds of the soil humus, fuivic acids play a cru- cial role in the formation of mobile metal species The most important process is the interaction of rlilvic acids with lron(III) as one of the basic mineral components of the soil. The specific features of iron fulvate complexes cause the formation of heterogeneous systems in soils, where poorly soluble gel-like forms of Fe fulvate are in a dynamic equilibrium with soluble (mobile) forms ca- pable of migrating along the soil profile with ground solutions Interaction of other metals, among them radionuchdes with various forms of iron fulvate complexes, is an important factor influenc- ing their migration behavior in soils In this work the distribution of microamounts of europium(UI) in a model system containing equivalent amounts of native tulvic acid and Fe(III) was studied at pH 1-9. A correlation was found between the solubilization of Fe fulvates and the phase behavior of Eu which is controlled by ion-exchange. At pH 2.75+0.1, fuivic acid and iron ate quantitatively precipitated as an insoluble gel. It was demonstrated by infrared that the gel material is an acidic mixed-ligand complex Fe(OH)(RCOO)2(RCOOH) containing a protonated carboxy group in addition to the carboxy and hydroxy groups coordinated to the metal This complex has a coordination-polymer structure with Fe(III) bridging ions In the region of minimum solubility of iron fulvate the ratio of Eu concen- trations in solution and in gel is 2:3. At pH 2.75-6.0, i.e., in the region which is the most interesting in view of the actual soil acid- ity, with increasing pH a considerable part of iron fulvate gel undergoes solubilization and passes into solution, the fraction of Eu occurring in the soluble (mobile) form remains in this pH range at a nearly constant level (-40%). Outside this range, both with the decreasing (<2.75) and increas- ing pH (6-9) a rather vigorous transfer of Eu(III), Fe(III), and the fulvate component to solution was observed so that at pH 8.5-9.0 all the components of the system pass entirely into the solu- tion. At low pH the solubilization proceeds via breakdown of the coordination polymer structure as a result of substitution of Fe(III) by protons. The mechanisms determining the solubilization of Fe fulvate in the region of high pH were found to be the neutralization of free carboxy groups in the fulvate structure with formation of Na-carboxylate hydrophilic groups and more complete hydrolysis of Fe(III).

-98- P2-24

CHEMICAL ASSOCIATIONS OF RADIONUCLIDES OF CHERNOBYL ORIGIN

G. Lujaniene", M. Bickelb, V.Lujanas", B.I. Ogorodnikov1, A. Mastauskasd, R. Ladygiened, D. Jaokunaite" "Institute of Physics, A.Gostauto 12, 2600 Vilnius, Lithuania ''European Commission, Joint Research Centre, IRMM, Retieseweg,B-2440 (Jeel, Belgium "Karpov Institute of Physical Chemistry, Obucha 10, Moscow, Russia dRadiation Protection Center, Ministry of Health, Kalvariju 153 2042 Vilnius, Lithuania

The atmosphere is the most mobile medium where pollutants can be transferred quickly and reach the most remote parts of the Earth. Depending on the emission nature, radionuclides spreading, transformation during the transfer and subsequent migration in the environment can be very different. Because of this, it is very important to know the properties of radionuclides at the moment of release, as this allows to evaluate the impact on animate nature and to predict and explain radionuclide migration. The concentrations of Chernobyl-derived radionuclides were measured from the Chernobyl accident till now in atmospheric samples. Chemical associations of 134B7Cs, '"Sr, 2j*U, ~38U, 238Pu and 239p240Pu were investigated using the Tessier method (Tessier et al.) and that described in (Livens & Baxter). Our results show that available forms (water-soluble and exchangeable) of L37Cs and "Sr carriers were characteristic of Chernobyl samples as opposed to the Pu isotopes which were present in hardly available forms. Moreover, it should be noted that the distribution of radionuclides in samples collected in Vilnius was different from that in samples collected in the zone near Chernobyl. Such differences were observed also in forest fire samples collected in Vilnius and detected during the forest fire experiment earned out in 1993 in a highly polluted Briansk region of Russia (Lujaniene et al.). This is can be explained by atmospheric trans- formation during the transfer. After the Chernobyl accident, the national situation with respect to radioactive pollution in Lithuania and other European states is conditioned by the transfer of radionuclides from highly contaminated areas of the Ukraine and Belarus. The investigation of speciation of radionuclides from Chhernobyl in daily and monthly aerosol samples and depositions during 1992-1997 shows variation in radionuclide properties depending on the origin (forest fires, dust storms, resuspention), season and meteorological conditions After dust storms in the Ukraine, two kinds of samples were registered in Vilnius: in the first case the distribution of 137Cs and '"Sr was close to that of the mentioned radionuclides in soil, and in the other case extremely insoluble caesium isotopes were found. In order to investigate possible radionuclide carriers formed during resuspention, some experiments were carried out using the Chernobyl soil, and chemical associations of 137Cs "Si", 234U, 238U, a'Pu and m240Pu were measured.

REFERENCES

Tessier A., Campbell P.G.C. and Bisson M. Analytical Chemistry, 51, 7, (1979). Livens F.R. & Baxter M.S. . Environ. Radioactivity 7, 1, (1988). Lujaniene G., Ogorodnikov B.I., Budyka A.K.,.Skitovich V. I., Lujanas V. J. Environ. Radioactivity, 35, 1, (1997).

-99- P2-25

CHARACTERIZATION OF THE REDOX BEHAVIOUR OF SPRUCE LIGNIN AND HUMIC ACID

B. Mack, A. Abraham, L. Baraniak, G. Bernhard, H. Nitsche Forschungszentrum Rossendorfe.V., Institute of Radiochemistry, P.O. Box 510U9, D-013J4 Dresden, Germany

In the process of uranium mine flooding in Saxony and Thunngia, Germany, spruce wood become degraded. The wood degradation process consumes oxygen and anaerobic conditions are created. The redox system Fe(II)/Fe(III) plays an essential role in the environmental water chemistry because the redox potential in deep waters under anaerobic conditions is mainly determined by the iron(III) to iron(ll) ratio. The redox behaviour of spruce lignin and humic acid was charactenzed by their redox potential and redox capacity. The reduction of Fe(III) by lignin and humic acid and the influence of these organic compounds on uranium were investigated. The first approach to the standard potential using a platinum electrode in combination with a silver-silver chloride electrode (3 M KCl) in a cell with liquid junction [1] was done in two ways: (1) by direct redox potential measurements [2] and (2) by redox titration with potassium hexacyanoferrate(III) [3], both in dependence on the pH The redox potential of spruce lignin at pH 0 determined in these ways was found to be 580±20 mV. That represents a rough E° which can be arranged in the series of redox couples with decreasing E°. The reducing capacity determined from the titration at pH 9 amounts to 15±0.5 meq/g. Iron(III) in non-complexing solution (0.1 M KCl) was reduced by lignin with a maximum capacity of 10±1.0 meq/g in the pH range 2 to 2.5. Humic acids of different origin are characterized in the same way. In addition, the iron(III) reduction by lignin and humic acid was examined in the pH range 3 to 5 by square-wave voltammetnc analysis after a four weeks equilibration under inert gas at 25°C. The iron(III) waves at -1.40 V and -1.60 V disappeared and the typical iron(Il) signal was found at -1.33 V (all potentials were measured vs. Ag/AgCl, 3 M KCl). Changing the iron(III)- lignin ratio at pH 4.7±0.2 (between 21O'J to 1.6-10" mol/L) the maximum lron(III) quantity that can be reduced by a given lignin amount (2 g/L) could be determined to 0.14 meq/g. The analytical proof of the formed iron(II) was carried out by spectrophotometnc determination with o-phenanthrohne. This sensitive method with a detection limit of 0.01 ppm iron(II) was adapted in such a way that iron(II) could be determined in the presence of iron(lll).

[1] Bard, A.J., Parsons, R, Jordan, J Standard Potentials in Aqueous Solution. Marcel Dekker Inc., New York, 1985, p. 8 [2] Szilagy, M: Valency Changes of Metall Ions Interaction with Humic Acids, Fuel 53 (1974) p. 26 [3J Matthiessen, A.: Untersuchungen uber das Redoxverhalten der Huminstoffe, Dissertation, Universitat Gottingen, 1989

-100- P2-26

INVESTIGATION OF RADIATION SITUATION ON THE TERRITORY OF BELARUS ON THE BASE MONITORING SYSTEM

Ivan I.Matveenko, Olga M.Zhukova, Maria G. Germenchuk, Ella D. Shagalova Stale Committee for Hydrometeorology, Republic Centre of Radiation and Environment Monitoring, Minsk, Belarus

A network of the Stationary stations for radioecological monitoring of the ecosystems, working according to special programs, has been established at the territory of the Republic of Belarus. Presently, the exposure dose rate of gamma-radiation is measured every day at 57 stations. The information is trransmitted to the Center of Radiation Control and Monitoring of Environment of the State Committee for Hydrometeorology. At 26 stations, located at the whole territory of the Republic, the level of the radioactive depositions from the surface layer of the atmosphere is measured every day. The content of radioactive aerosols in air is measured eveiy day in six cities of Belarus. The continuous control over contamination of the surface water and bottom depositions is carried out at five main rivers of the Republic, passing through the contaminated territory: Dnepr, Sozh, Iput and Besed. Monthly control over the content of radionuclides in surface water is carried out: the samples of water are taken with simultaneous measurement of flow rates, the samples of the surface water are analyzed for content of total p-activity, caesium-137 and strontium-90. The State Committee for Hydrometeorology carries out the radioecological monitoring of the soil at the sampling sites, which includes 18 landscape-geochemical areas and 181 sampling sites. Study and forecast of vertical and horizontal migration of radionuclides is carried out at the landscape-geochemical areas with different types and variations of soil in various radioecological and physico - geographical conditions. The results of the control of radionuclides in different media (air, water.soil) are accumulated in the data bank of the Republic The State Committee for Hydrometeorology is carrying out the control in the zones of the effect of nuclear power plants, located at the territories of the neighbouring states. The following parameters are controlled in the zone of the effect of the Ignalina NPP: • exposure dose rate of gamma-radiation (every 3 hours); • radioactive fall-outs, from the atmosphere (total p-activity, the content of the short-lived radionuclides, caesium-137 and strontium-90), • scale gamma-photograph are conducted annually, • content of radionuclides in the surface water and bottom sedimentation's of the Dnswyaty lake in controlled 4 times in a year; • control over the content of radionuclides in the soil at the sampling sites is carried out; • monitoring of atmospheric depositions is conducted; • automated system of measurement of the exposure gamma-dose is put into practice In the zone of the effect of the Rovno NPP (Pinsk town), the content of radioactive aerosol of the atmospheric air is controlled every day, the content of caesium-137 and strontium-90 in the atmospheric aerosols is determited, the exposure dose rate of gamma-radiation is carried out every day. In the zone of the effect of the Smolensk NPP (Mstislavl town) the Control over the exposure dose rate of gamma-radiation is carried out every day.

-101- P2-27

PLUTONIUM ISOTOPES CONCENTRATION IN THE GROUND LEVEL AIR AND RAIN SAMPLES FROM KRAKOW

J. W. Mietelski, K. Kozak, B. Ws$s, M. Jasinska, J.O.Krupa Environmental Radioactivity Laboratory, I he Henryk Niewodniczanski Institute of Nuclear Physics, PL-31-342 Krakow, Poland, Radzikowskiego 152 si.

One of our Aerosol Sampling Station model 500 [1] was used for a non-rouline collection of aerosols Sixteen Petryanov type air filters were exposed from March to August 1995 and then combined into two sets of 8 filters (three months of exposition each). Each set contained aerosols from ca. 0.5 million m1 of the air After dry ashing at 600°C each set gave about 20 g of ash. Plutonium was determined by alpha spectrometric measurements on the Silena Alpha-Quattro spectrometer with Canberra PIPS detectors. The measurements were preceded by radiochemical procedure [2,3] routinely used in our Laboratory for forest soil samples An example spectrum is displayed on Fig 1. Observed activities were on the level of few nBq/mJ The most interesting finding was that the plutonium isotopic ratio (23sPu:239i2't0Pu) for both samples fell between the values typical for global and Chernobyl fallout (0.04 and 0.55, respectively ). This suggests that the Pu isotopes in the air originate either from the mixed (Chernobyl and global) fallout or (and) from the other then expected sources (for example via aquatic pathway). Further investigations are planed to clarify this point. Similar procedure has been applied for about 200-liter rain samples collected in 1996 and in 1997 The analyses of the samples is still not finished in the moment of writing this abstract. The results will be presented on the poster.

Fig 1. Example spectrum of the Pu strip of the aerosol sample collected from June to August (ca. 0.5 million m3 of air). Measurement time: 18 days, close geometry, detector: PIPS 2 Canberra 450 mm area, NdF3 co-precipitated source .

References J Jagielak, M.Biernacka, R.Zarucki. Book of Extended Synopses of International Symposium on Environmental Impact of Radioactive Releases 8-12 May 1995, IAEA-SM-339/76P, IAEA Press, Vienna 1995, p. 216-217. J.J. LaRosa, E. Cooper, A. Ghods-Esphahani, V Jansta, M Makarewicz, S Shawky, N. Vajda./. Environ. RadioactivM, (1992) p. 183-209. J.W.Mietelski, B.Was, Applied Radiation and Isotopes, 46 (1995) 1203-1211

-102- P2-28

SORPTION OF NEPTUNIUM ON IRON OXIDE

Kotaro Nakata, Takashi Fukuda, Shinya Nagasaki, Satoru Tanka, Atuyuki Suzuki, Tadao Tanaka, Susumu Muraoka Departments of Quantum Engineering and System Science, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan

According to the performance of allocation analysis on multi-barrier system for high-level ra- dioactive waste disposal, it is found that Np dominates the hazard at the exit of the natural barrier, namely at the inlet of the biosphere. Neptunium-237 is present in the high-level radioactive wastes, although relative to other radionuclides the amount is small. However, because of its long half-life (J\a = 2.14 x 106 y) and its mobile nature under aerobic conditions due to the high chemical stability of the pentavalent state, NpO2\ ^'Np is considered a possible long-term hazard in ecosystems. An understanding of Np sorption behavior is required to describe the transport of it in surface and groundwater systems quantitatively. Under aerobic conditions, the weathering of iron containing primary rocks leads to the forma- tion of secondary iron oxide minerals. Precipitates of these minerals can be found in surface and groundwater systems. These minerals show a varying degree of crystallinity and can occur as colloids or coatings. These iron oxides, especially Fe-hydroxides, e.g., ferrihydnte, are much better scavengers of trace elements in natural waters. Therefore, the sorption data of Np on iron oxides will be required to describe the mobility of Np in natural waters. Furthermore, there is a possibility of reduction of Np(V) to Np(IV) at the surface of minerals containing Fe(II) How- ever, few works have been performed to investigate the reduction of Np(V) to Np(IV) and the sorption/precipitation of Np(IV). In the present work, we carried out the sorption experiments of Np(V) on goethite (a-FeOOH), magnetite (Fe3O4) and biotite by batch method and studied whether Np(V) is reduced to Np(IV) or not. Iron oxide was placed in a polyethylene tube and a spike of Np(V) solution was added. The pH was adjusted to pH = 1 to 6 by using HNO3 and NaOH, and the ionic strength by using NaNC>3 Considering the dependence of Np sorption on pH, ionic strength and temperature, we discussed the sorption behavior of Np on iron oxides with and without Fe(II) Furthermore, we compared the sorption rate with reduction of Np(V) ion by Fe(II) ion in a aqueous solution to obtain the information on reduction mechanism on the surface

-103- P2-29

GEOCHEMICAL FAR-FIELD PROCESSES IN PERFORMANCE ASSESSMENT FOR UNDERGROUND RADIOACTIVE WASTE REPOSITORIES

U. Noseck Geselhchqftfiir Anlagen- und Reaktorsicherheit (GliS) mbH, Braunschweig, (krmany

The release and transport of radionuclides from underground repositories into the biosphere is controlled by geological and technical barriers As part of this multibarner system geological formations play a decisive role with respect to the long-term safety of repositories Different geochemical processes can cause a significant reduction of the contaminant concentration on its way through the geological formations in the far-field of the repository. The first part of this contribution will show the influence of geochemical processes considered in performance assessment, as linear and nonlinear sorption or colloidal facilitated contaminant transport, respectively. Relevant nuclides with respect to the dose rates will be identified. The transport models and data applied in performance assessment are usually derived from laboratory experiments For technical reasons those experiments can only be performed over limited time periods. However, as long travelling distances have to be passed through the geosphere thus requiring geological time frames, the effects of geochemical processes have to be assessed for correspondingly long times, which are in the order of million years The investigations of suitable geological analogues may help to better understand the complex interrelations between transport and retention of radionuclides under natural conditions and may proof the application of the spatial and temporal extrapolation of experimental results to real systems. In the second part of this contribution results from international natural analogue studies dealing with nuclide migration in geological systems will be evaluated and discussed in the scope of the performance assessment of German repository concepts.

-104- P2-30

PECULIARITIES OF PHYSICO-CHEMICAL STATE OF 137Cs IN PEAT-BOG SOILS

S.V.Ovsiannikova, G.A.Sokolik, E.A.Eismont, S.Ya.Rubinchik Helorussian Stale University, Laboratory of Kadiochemisliy, Minsk

The vast territories of Belarus, Ukraine and Russia that were contaminated by the fallout from the Chernobyl accident are either peat lands or peat bogs A large portion of the runoff to the Dnieper system is associated with contaminated bogged lands of Belarus. The aim of this work was to analyse the mobility ofly7Cs in the ecological systems with different kinds of peat-bog soils on the basis of data on radionuclide forms in the soils. The sites of observation are situated at a distance of 20-2&0 km from the Chernobyl nuclear power plant. The level and character of contamination of the sampling sites and also the conditions of radionuchde migration are typical for the affected regions of Belarus with peaty soils. The investigation of the radionuclide occurence forms was fulfilled by the method of the sequential selective desorption with application of dialysis method. According to these methods the mobile and "fixed" forms of radionuchdes were separated. It was established that in all investigated soils a main quantity of l>7Cs (61-96% of its total amount in the soil samples) is in a "fixed" form (insoluble in IM HC1). Even in high organic peat- bog soils, where contents of mineral components were only 2-5%, unexchangeable forms of radiocaesium predominated, although the contents of the unexchangeable radiocaesium were lower than in other peat-bog soils. It was shown that a mineral part of soil complex (in particular, clay minerals) plays a definite role in "fixation" of radiocaesium. A role of soil organic matter in its "fixation" have not been finally cleared up It was one of the tasks of present investigation The data on the occurrence of the forms of "7Cs in the soils, obtained according to modified Tessier scheme, point at a weak influence of humic substances on the state and mobility of radioisotope in a soil medium: only 3- 6% of l37Cs are fixed by organic matter of soils. Our additional experiments with destruction of organic substances of peaty soils in the soft conditions (in which clay minerals were not destroyed) also have confirmed the conclusion about an insignificant role of organic matter in "fixation" of '"7Cs. The received information is the foundation for evaluation of radioecological situation and prediction of radionuclide transfer in the ecological systems with different peaty soils. It gives an opportunity to designate the countermeasure strategy for safe use of the contaminated peaty lands.

-105- P2-3I

STUDY OF THE CONCENTRATION RADIONUCUDES IN THE ENVIRONMENT OF ENTERPRISES FOR DECONTAMINATION OF LOW AND INTERMEDIATE LEVEL RADIOACTIVE WASTES

Pol'skij O.G., Paramonova T.I., Panchenko A.V. MosSIA "Radon"

The results of radioecological inspection of enterprises for decontamination of radioactive wastes in the period from 1989 to 1997 years are presented. Three zones are inspected on each enterprise: strict regime zone (SRZ), sanitary-protective zone (SPZ) and supervision zone (SVZ). The potential waste sources presents in SRZ. The exposure dose rate is measured in every zone of' all enterprises and the samples of the soil, vegetation and water are carry out. Maintenance of some radionuciides and alpha-, beta-emission products of those samples are investigated. The statistical date treatment shows differences of the radiation levels in SRZ, SPZ and SVZ of each enterprise are negligible with 0,95 confidence probability. It allows to conclude for the absence of the noticeable influence of the enterprises on environment. However it is no exception that such conclusion is consequence of the insufficiently precision measuring, small statistical volume or nonrepresentativeness of samples More effective criterion is based on the principle of independence c f dates are applied to different enterprises separated with large distances. The method supposes the regression analysis of the connection of radionuclide contents in SRZ and radionuclide contents in SPZ and SVZ for all inspected enterprises. The significant correlation between the radiation levels in different zones for all enterprises is recognised. The region radiation background gives the principal contribution in the recognised correlation. The correlation vanishes to subtraction this background The results for SVZ are taken as the background. The absence of correlation and independence of dates for all enterprises allows to conclude that presence of the radioactive sources in SRZ no affects on situation in SPZ and especially in SVZ. So that within the limits of the available measuring precision no influence of the inspected enterprises on environment has been observed

-106- P2-32

MODIFIED SYNTHETIC HUMIC ACIDS FOR THE INVESTIGATION OF HUMIC ACID COMPLEXATION BEHAVIOR WITH URANYL IONS

S. Pompe, M. Bubner, K. H. Heise, H. Nitsche Forschungszentrum Rossendorfe.V., Institute of Radiochemistry, P.O. Box 510119, D-01314 Dresden, Germany

The influence of humic substances on the speciation of actinide ions and their migration behavior in natural aquifer systems is of great interest within environmental research. Specified knowledge about this is required, for instance, to develop strategies of the risk assessment for long-time safety in the regions of the former uranium mining in Saxony and Thuringia. Due to the complex and heterogeneous nature of humic substances a thermodynamic founded description of their complexation behavior with metal ions is difficult. Numerous uncertainties exist in the description of the complexation process, e.g., the kind and number of complexing functional groups is uncertain. Therefore, it is necessary to investigate the complexation process with well defined model substances. We synthesize and characterize humic acid functionality models from reducing sugars and a- amino acids, with functional properties comparable to those of natural humic acids with respect to type and number of functional groups1. Former measurements have shown that this synthetic humic acids mimic the interaction humic acid - metal ion very well2'3. This work deals with the possibilities to synthesize modified humic acids, e.g., humic acids with blocked phenolic OH groups. With this model substances we investigate the influence of phenolic OH groups on the complexation behavior of humic acids with uranyl ions by time- resolved laser-induced fluorescence spectroscopy We expect to get a better understanding of the humic acid - metal ion interaction process and to gather information regarding geochemical modeling in the presence of humic acids.

l.Ponipe, S , Bubner, M., Denecke, M.A., Reich.T, Brachmann, A., Geipel, G., Nicolai, R., Heise, K.H.. Nilsche, H : A Comparison of Natural Humic Acids with Synthetic Humic Acid Model Substances: Characterization and Interaction with Uranium(VI). Radiochim. Acta 74, 135 (1996).

2.Pompe, S., Brachniann, A., Bubner, M., Geipel, G , Heise, K.H., Nitsche, R: Determination and Comparison of Uranyl Complexation Constants with Natural and Model Humic Acids, in preparation.

.I.Denecke, M.A., Pompe, S., Reich, T., Moll, H., Bubner, M., Heise, K.H.. Nicolai, R., Nitsche. H : Measurements of the Structural Parameters for the Interaction of Uranium( VI) with Natural and Synthetic Humic Acids using EXAFS. accepted for publication in Radioclumica Acta.

-107- P2-33

PROBLEMS OF INVESTIGATIONS OF MICROBIAL TRANSFORMATION OF NATURAL SUBSTANCES. METHOD OF RADIOCHEMICAL MATRIX TEST IN ANALYSIS OF MICROBIAL CHANGING OF CHELATE PROPERTIES OF NATURAL ORGANIC MATERIALS AND BEHAVIOUR OF RADIONUCLIDES IN ENVIRONMENT

V.B.Ribalka, I.N.Sirchenko, V.V.Serbinovich, S.I.Nicolenko Chernobyl Scientific & Technical Centre for Internationa! Research, Chernobyl; Joint Venture "Khimtechservis", Odessa

Vital activity of microbiocenosis and their influences upon the behavior of radionuclides have been studied Today no data exist on the mechanisms of change of migration properties of radionuclides. Attempts to describe microbial processes as common chemical reactions of second order turned out to be unreliable for predictions. The method of Radiochemical Matrix Testing has been used for the study of chelate characteristics change of organic substratums due to the vital activity. The method is based on the analysis of sorption of a radionuclide-tracer in 4-component systems: investigated substratum (solid phase) - ions of the radionuclide (water phase) - competing cation-macrocomponent(water phase) - competing soluble chelate with known model chelate characteristics (water phase). For the description of the chelate characteristics the following carrier-less gamma-radionuclides were used as radioactive tracers: Sr-85, Co-57, Cs-137, Y-88, Ce-139, Mn-54, Cd-109, Am-241, Pu-237. All data obtained for characterizing the organic material (substrata) are presented in the form of 3-dimensional matrixes with coordinates: pH - type of the competing cation - degree of the radionuclide-tracer extraction by substratum material. The soluble chelate with known model chelate characteristics was used to extend the possibilities of the investigated substrata characteristic description. The systems obtained are being applied for practical testing of the microbiocultures extracted from the natural objects sampled in the 30-km Chernobyl Zone. Test matrixes have shown that collecting of nuckdes in the course of the microbial humufication natural substratums (sheets, herbs, pine-needles) provide materials that distinguish substantially from the derived salicylic or phtahc acids, the characteristics of which usually determine the chelate characteristic of humic acids The effects of the temporary factor and cyclical change of a temperature mode, influence of temporary factor and round-robin changing a warm-up mode were investigated in the course of microbial natural substratum transformations. The results obtained show that the cyclical changing of external conditions can play a decisive role for both the rate of chelate properties transformation and for the depth of conversion - qualitative change of the chelate properties of the substance. Value of stability constants of complexes of tracer nuclides with the material of substrata increases in the course of microbial transformations sometimes even by a factor of 1000 - 10 000. The stability constants attair values by 4 orders of magnitude greater than those of ammo acids, by 2-3 orders greater than the substance traditionally used for the description of the chelate properties of the humic acids. The method allows not only to evaluate the bond strength of the radionuchdes to any complex successfully but also to give an information on the qualitative compositions of chelate-forming groups and of the quantity of active centres in mixtures. Radiochemical method of testing the chelate-forming properties of natural organic substances used for studying the living microbiocenosis under natural conditions will be used to find an answer to the question what reasons cause the changes of the radionuclides forms in natural objects and how they change the migration characteristics of radionuchdes.

-108- P2-34

INTERACTION OF URANIUM(VI) WITH ARSENATE IN AQUEOUS SOLUTION STUDIED BY TIME-RESOLVED LASER-INDUCED FLUORESCENCE SPECTROSCOPY (TRLFS)

M. Rutsch, G. Geipel, G. Bernhard, H. Nitsche Research Center Rosxendorf e.V., Institute of Radiochemistry, P.O. Box 510119, D-01314 Dresden, Germany

Seepage waters of mine tailing piles and waters of flooding uranium mines in Saxony and Thuringia contain uranium and arsenic of about 2.10"5 M and 5.10 "* M. The dissolved arsenic is 2 present primarily as arsenate anions like H2As04", HAsO4 ' and AsO4" The great variety of different species in the uranyl/arsenate-system requires a detailed investigation to determine their influence of the migration of uranium(VI) in the above mentioned areas. Only solid uranyl/arsenate phases, e.g. UO2HAsO4.4H2O, UO2(H2AsO4)2.xH2O (x=l,3) and (UC>2)3(AsO4)2.10-12 H2O had been characterized concerning structure and thermodynamic properties. Presently, nothing about the complexation behavior of uranyl with arsenate had been published in the literature. Assuming a similar complexation behavior of arsenate to phosphate three possible uranyl/arsenate complexes, UO2HAsC>4(aq), UO2H2ASO4* and UO2(H2AsO4)2(aq) were calculated and their existence was confirmed in the experimental work. The complex stability constants of these three uranyl arsenate were determined for the first time over a pH-range 2 to 5, with different arsenate to uranyl ratios and a constant ion strength at 0.1 M NaC104, using time-resolved laser-induced fluorescence spectroscopy (TRLFS). + The measured main fluorescence bands are centered for UO2H2AsO4 at 493 nm, 515 nm and 537 nm, for UO2(H2AsO4)2 (aq) at 496 nm, 518 nm and 542 nm and for U02HAs04 (aq) at 504 nm, 526 nm, 550 nm and 577 nm. Besides, the fluorescence lifetimes of the uranyl/arsenate complexes were measured.

-109- P2-35

MONITORING OF NATURAL FACTORS IN CZECH SPELEOCENTRES

Daniel Sas, Old rich Navratil, Petr Sladek Department of Chemistry, Military University 68203 Vyskov, Czech Republic

The children's medical institutions in Zlate hory and Sloup are year-round health-service establishments providing medical treatment for asthmatic children (6 to 14 years of age) from the entire republic. The treatment of a group of 30 - 35 children takes 3 weeks with 3 hours of treatment per day. Javofic'ko is a reserve locality The actual medical treatment is administered in adapted parts of the caves (Sloup, Javoficko) and m a former copper-mine (Zlate hory) The radioactivity of radon and its daughter products (DP), gamma doses, the concentration of positive and negative light ions and meteorological data (temperature, air pressure, humidity, air 2 2 flow, concentrations of SOi, NOX and also Ca * and Mg ') were measured in these speleotherapeutic centres within the framework of the project PHARE in the years 1994 - 1996. From the measured data it follows, that there is a direct proportionality between the activity of radon and the concentration of negative and positive light ions in the given locality, however, with different constants of proportionality in different localities The activities of radon and its DP show short-termed and long-termed fluctuations in time. The changes of temperature of outer atmosphere, air pressure and flow play decisive part in limestone caves. Minimum short-termed fluctuations of activities were observed in the ore gallery Zlate hory with defined connections to the outer atmosphere. The therapeutical effect is utterly climatic while the cave effects are complex: the inner atmosphere has a constant temperature (about 7.5 °C) and humidity of more than 95 %. This atmosphere does not contain any allergenes (such as dust, pollen and bacteria), on the contrary it has high self-cleaning capabilities and high concentrations of radon and important charged light- ions. These ions have an indisputable effect on human beings, but detailed interactions within organisms are not well-known. They are produced predominantly by ionizing the air molecules by the alpha radiation Ionizing radiation in caves has a stimulating effect (hormesis) up to a certain value of dose equivalent. This effect manifests itself with increased production of rectifying enzymes in connection with chromosome aberation of lymphocytes, increased production of new cells, stimulation of the immune system and reduction of cancer formation risk [1] We assume this upper value for hormesis is 50 mSv [2]

REFERENCES

[I] HOFMANN W.: Z.Phys.Med.Baln.Med.Klim. 19, 69(1990) [2] NAVRATIL O ,RICNY D ,SANDR1 B..SLAVlK P ,SURY J..STELCL J Abstr.of the Int. Symp.of Speleotherapy, Bad Bleiberg, Austria, p.5, Oct. 1992

-110- P2-36

ACTIVITY CONCENTRATIONS OF 7Be, z10Pb AND 137Cs IN SURFACE AIR IN TRIPOLI

M. A. Shenber Radiation Protection and Health Physics Department Environmental Radiation Measurements Division Tajoura Nuclear Research Centre P. O. Box, H4326 Tripoli, Libya

Activity concentration of radionuchdes in surface air in Tripoli have been measured using gamma-ray spectrometry. Average activity concentrations of 7Be, 2l0Pb and 137Cs in surface air in Tripoli were 2100, 160 and 1.7 u.Bq m' It was estimated that the annual effective dose equiva- lent to adult from inhaled 7Be, 2l>b and B7Cs averaged 2.96 tiSv.

REFERENCES

(1). Pendleton, R. C , Mays, C. W , Lioyd, R. D. & Church, B W (1965) Atmospheric-Level Effect on 137Cs Concentration Journal of Health Physics. 11(12) 581 (2). 1CRP International Commission on Radiological Protection Limits for Intakes of ra- dionuchdes by Workers. 1CRP Publication 30, Annals of the 1CRP Vol-3, No. 1/4 (1979) (OXFORD: Pergamon Press). (3). Whicker, F. W.; Nelson, W. C. & Gallegos, J K. (197). Fallout l37Cs and ^Sr in Trout from Mountain Lakes in Colorado. Journal of Health Physics. 23(4): 519. (4) UNSCEAR (1993). The United Nation Scientific Committee on the Effects of Atomic Ra- diation Sources to the General Assembly with Annexes, Effects and Risks of Ionizing Radiation. United Nation Publication, New York

-111- P2-37

CHARACTERIZATION OF AQUATIC HUMIC SUBSTANCES FROM BOG WATER AND THEIR COMPLEXATION BEHAVIOR TOWARDS URANYL IONS

K. Schmeide, H. Zanker, K.H. Heise, H. Nitsche Forschungszentrum RossemJorfe. V., Institute of RaJiochemistry, P.O. Box 510119, D-01314 Dresden, Germany

The investigation of the effects of humic substances (humic and fulvic acids) on the migration of radionuclides is crucial to allow assessment of their impact on long-term safety of both radioactive waste repository sites (eg Gorleben) and abandoned uranium mines in Saxony and Thunngia. The humic substances are extracted from bog water of the 'Hochmoor Kleiner Kranichsee' which is situated in the direct environs of the uranium mining sites of Johanngeorgenstadt (Saxony) The humic material is separated into humic and fulvic acids, and characterized in terms of their elemental composition, functional properties including proton exchange capacity, charge/size ratios and spectroscopic characteristics. Colloid-chemical studies are carried out by means of photon correlation spectroscopy to determine the size and the size distribution of particles. Furthermore, complexation studies of site specific humic substances with uranyl ions are conducted. The results are compared with data of a commercial humic acid from Aldrich.

-112- P2-38

NATURAL RADIONUCLIDES IN DRINKING WATER IN AUSTRIA

Franz Schonhofer1, Maria Feigl-Heihs2 and Karl Irlweck2 'Federal Institute for Food Control and Research, Vienna, Austria 2Institute of Inorganic Chemistry, University of Vienna, Austria

During the last years attention has been drawn to the fact that dnnking water may contain considerable amounts of natural radionuclides. Furthermore many naturally occurring radionuclides are alpha-emitters, are highly radiotoxic and pose therefore health risks. Such considerations require a survey on drinking water supplies. Until now one fourth of the Austrian territory has been covered by the survey. Preliminary results will be shown on the concentration of Rn-222, Ra-226, uranium, Pb-210 and Po-210. Dose implications and legislation regarding limits for radionuclides in drinking water will be discussed and the situation will be compared with legislation and proposals for limits which have been made.

-113- P2-39

THE INVESTIGATION OF RADIONUCLIDES AND MORPHOLOGY IN HOKUTOLITE FROM HOKUTO HOT SPRING

Shih-Chang Lu(1)(2) Institute of Nuclear Energy Research, Lung-Tang, Republic of China '"

Fu-Yuan Huang, Chin-Wang Huang(2) Department of Chemistry, Chung Yuan Christian University Republic of China a'

A series of hot spring water samples and their sediments were collected from Hokuto area in Taiwan. These samples were analyzed for the radionuchdes Ac-228, Ra-226, Bi-212, Bi-214, Pb-212, Pb-214 and Tl-208 by gamma ray spectrometry with Ge detector. The results showed interesting relationship among these samples. The principal of existence of these nature nuclides in the rocks was further confirm from the results. The analysis of elemental composition was performed with X-ray diffraction, SEM (Scan Electronic Microscope) and EDX (Energy Dispersion X-ray) methods. The major components of Hokutolite were BaSC^and PbSO4. The concentration of Ba and Pb in the Hokutolite hot spring water and sediment samples were correlated to their temperature and pH condition More detailed discussions of this relationship were included in this report.

-114- P2-40

PROBLEMS OF RADON IN KAZAKSTAN

Sirajet Khajekber, I.V.Kazachevskiy and G.I.Krasnov* Institute of Nuclear Physics, National Nuclear C Center, Republic oj Kazukslan *All« Volkovgeo/ogy»

In a considerable part of the territory of Kazakstan there are intrusive rocks with increased contents of natural radionuchdes, as well as spacious zones of tectonic breakages Zones with increased radioactivity and tectonic breakages with increased emanation lead to an increase in the concentration of radon and its daughter products in these premises, so their influence becomes dominating one in the collective dose An attempt was made to map regional radiation m the territory of Kazakstan on the basis of geological data taking into account information on the radioactivity of mountain rocks, waters and uranium-ore, the occurrence of rare metals and other ores, with which natural and technogeneous radioactive anomalies and contammationsare connected First of all these ace. • areas with highly radioactive rocks with increased radon emission in districts rich in uranium ore and rare metals in north and central Kazakhstan, as well as the mountain and sub-mountain regions of the southern and southern-eastern territories of Kazakstan, areas with underground waters of artesian basins with a high content of uranium and radium in the uranium-ore provinces of southern regions, • individual sources of underground (thermal) waters of western Kazakstan, territories with some oil-producing mines with increased content of natural radionuclides in water layers causing radioactive contaminations of the earth surface during the technological processes of oil mining. From geological criteria certain populated areas with potentially dangerous radon occurrence are selected. Concrete data are presented of the investigation on radon-containing soil of some populated areas, on the contents of radon in certain premises, and on fraction of radon from the underlying surface entering the premises of existing buildings. There are considerable problems in the investigations concerning detailed radiation-ecological studies of the territory of the Republic, and of the radiohygienic inspection of the population living in potentially dangerous regions in order to obtain objective data about the level of irradiation from natural sources of ionizing radiation that the population is exposed to

-115- P2-41

THE MICROBIAL DANGER FROM THE 4th UNIT OF CHERNOBYL NPP

I.N.Sirchenko, V.V.Serbinovich, S.l.Nikolenko, I.P.Visekancev, I.J.Simonovskaya, V.B.Ribalka, G.I.Petelin Chernobyl Scientific & Technical Center for International Research, Chernobyl; Joint Venture "Khimtekservis",OUessa

Liquidation of the consequences of the Chernobyl NPP 4th unit destruction created conditions for the formation of a specific microbiocenosis. For filling up the destroyed reactor materials containing all vital components for the development microorganisms - sodium tripolyphosphate, alumosilicates materials, different phosphate fertilizers - were used. Various experts in the reactor technology estimate that the reactor contains several hundred tons of graphite - a source of carbon. Total volume of water masses in the object «Shelter» could be estimated to 3000 t, that creates good conditions for the development of microorganisms. Moreover, action of radioactivity fields ranging from 300 up 3000 R/h during 10 years represents a source of mutations. So the determination of microbiocenosis in water masses of the object «Shelten> presents an actual problem. We have made the microbial analysis of water samples from the object «Shelter». As a result of preliminary studies the following bacteria were found: group Cyanobactena, family Bacillaceae - genus Bacillus, Clostridium, family Myxobactena, genus Pseudomonaceae, genus Cytophaga, genus Rhizobium, genus Eshencichia, genus Azotobacter, family Actinomycetaceae and Micrococcus denitrificance. 6 types were not identified. Discovered mushrooms: Penicillum, Aspergillus, Tnchoderma. 4 sorts were not identified. Representatives of family Pseudomonadaceae and Actinomycetaceae are capable to destroy a crystalline lattice of graphite and transform it in a nourishing organic substances. So graphite of the 4th unit should be considered as a source strong watersoluble chelate with the enormous capability to carry out radionuclides. Representatives of family Myxobacteriaceae are also capable to use as substratum materials of artificial origin - paraffins, oil, mothball and other products of oil. Majority of the discovered microorganisms are not demanding to the nourishing potentials of the environment and that means that the materials of artificial nature, that are in the unit, are fully suffient for their successful existence Vital activity of microorganisms is connected with the possibility to secrete into the environment the products of their metabolism. Some of them are able to form strong chelates, for example, oxalic acid is able to dissolve the uranium matrix of the fuel. Using the method of electron microscopy traces of corrosion of biotic origin on hot particles were also discovered. Identified groups of microorganisms are capable to select materials, they possess strong chelate ability with respect to radionuclides and raise their agility So the microbial factor increases the factor of radiation danger of the object «Shelter».

-116- P2-42

THE DISTRIBUTION OF POLONIUM 210Po AND RADIOLEAD 210Pb IN THE BALTIC CRUSTACEAN SADURIA ENTOMON

Piotr Stepnowski1"2 and Bogdan Skwarzec1 Polish Academy of Sciences, Institute of Oceanology, ill. Powstancow Warszawy 55, 81-712 Sopot, Poland University of Gdansk, Faculty of Chemistry, ul. Sobieskiego 18/19, 80-952 Gdansk, Poland

Naturally occurring radionuclide 210Po and radiolead 2l0Pb have been measured in tissues and organs of the Baltic crustacean Saduria entomon. The highest activity concentration of 210Po were found in hepatopancreas and alimentary track which together contributed to more than 83 % of the whole body 21clPo activity. High concentrations of radiolead 210Pb were found as for its granddaughter in hepatopancreas and in hemolymph. In order to recognise elevated concentrations of 210Po in crustacean hepatopancreas, preliminary subcellular study has been undertaken. Results from this experiment showed that 2I0Po is highly accumulated in cytoplasmatic pellet exceeding 62% of the whole polonium content in the hepatopancreas. No clear correlation of Po and protein content was found.

-117- P2-43

NEW ENTEROSORBENTS AND SORPTIVE FODDER ADDITIVES FOR RADIONUCLIDES REMOVAL FROM THE ORGANISM

V.V. Strelko Institute ofSorption and Problems of Endoecology of National Academy of Sciences of Ukraine, 13 General Naumov Str., Kiev, 252164, Ukraine.

Along to complexons, various sorbents (BaSO4, ion-exchanging resins, prussian blue, etc.) are also used for radionuclides removal from the organism. Due to radio ecological problems, faced in Ukraine after the accident at the Chernobyl power station, the urgent necessity in creation of means and preparations for radioecological protection of the organism appeared. These means and preparations should be suitable for the large-scale usage for the population at the territories, polluted by radionuclides. The data about character of distribution in biological media and dynamics of freshly formed radionuclides in the first months after the accident, are given. Peculiarities of Cs-137 accumulation in the organs and tissues in period after accident were examined. Experimental and clinical data about oral sorbents on base of oxidized carbonic sorbents and modified inorganic ionites providing the accumulation prevention and accelerated decorporation of all the radionuclides spectrum from the organism are also presented. In particular, it is shown that the usage of synthetic and fruit stone oxidized , having grafted carboxyl or phenol groups in a surface layer, decreases (6-8 times) the accumulation of La-140, Ba-140, Ce-144, Te-132, Zr-95, Nb-95, Ru-103(106), Cs-134, Cs-137 and others in the body and provides their decorporation. Due to general detoxication action of oral sorbents, a considerable improvement of the body biochemical indexes is observed, the number of diseases and pathological states, connected with chronical organism irradiation by incorporated radionuclides essentially decreases. The data about developing combined oral sorbents capable selectively to remove radio- cesium from the organism and positively influence on activity of internal organs are presented.

-118- P2-44

URANIUM MIGRATION AND FIXATION IN A WEATHERING PROFILE IN GRANITIC ROCK

J. Suksi*, A. Lindberg**, M. Siitari-Kaupi*, E.S. Flitsiyan***, P. Klobes****, J. Goebbels****, K-H. Hellmuth***** * Laboratory of Radiochemistry, University of Helsinki, Helsinki, Finland ** Geological Survey of Finland, Espoo, Finland *** Institute ofNuclear Physics, Uzbekistan Acad- of Science, Tashkent, Uzbekistan **** Federal Institute for Material research and Testing, Berlin, Germany ***** Finnish Radiation and Nuclear Safety Authority, Helsinki, Finland

Thorough understanding of the key processes and factors governing the long-term migration of radionuclides observed in complex natural systems is essential for the evaluation and confidence building in the conceptional models forming the basis of performance assessments for repositories for high-level radioactive waste in deep geological formations. The time scales of the migration of uranium in a weathering profile in muscovite granite boulder blocks could be constrained by previous uranium series disequilibrium studies to the period after the last glaciation in Finland. In the rock having a background level of uranium between 10 and 15 ppm a narrow zone of uranium enrichment up to 275 ppm was observed in a narrow weathering rim. In this study, the information necessary for interpretation and modelling of the migration processes is given: (I) The uranium concentration profile and the isotope disequillibna were measured and interpreted in relation to the depth from the weathered surface, (n) The properties of the matrix governing migration by diffusion and retardation by chemical interaction were measured (porosity- and pore size- as well as internal surface distributions) by impregnation with 3H- and 14C-PMMA and mercury intrusion-computer tomography; microprobe studies of the weathering of plagioclase and biotite and of fissure fillings; SIMS of biotite surfaces and the oxidation state of iron in biotite and plagioclase by Mossbauer spectrometry; (in) The fixation of uranium in the rock matrix was studied by fission- and alpha track methods (location of ,,old" and ,,young" uranium) and selective leaching methods giving information on the strength and nature of uranium binding. The latter method can help us to distinguish between paleo- and recent uranium migration processes Additional information will be gained by the investigation of the oxidation state of the fixed uranium

-119- P2-45

SORPTION-DESORPTION OF CESIUM ON-FROM SUITE AND ILLITE COATED WITH PETROLEUM WITH REFERENCE TO THE OKLO NATURAL FISSION REACTORS

Gyula Szab6, Judit Guczi, "Frederic Joliot-Curie" National Research Institute, P.O. Box 101, H-177S Budapest, Hungary

MireiUe Del Nero Centre de Recherches Nucleaires Chimie Nucleaire et Physicochimie des Rayonnements, 67037 Strasbourg, France

Francois Gauthier-Lafaye Centre de Geochimie de la Surface, CNRS, 67084 Strasbourg, France

For 0.1 to 1.0 Myr there were natural nuclear reactors 1968±50 Myr ago in Gabon, Africa. They are small pockets of highly uraniferous, hydrothermally altered sedimentary rocks in Oklo, Okelobondo and Bangombe uranium ore deposits. The natural reactors contain illite, Fe, Mg chlorite, uraninite and some quartz. Several of them also contain abundant carbonaceous matter (up to 66% by weight) C^. in heterogeneous distribution with clay and quartz. To elucidate the containment and migration of some of the radionuclides in the natural reactors, the sorption-desorption processes on-from illite of cesium was determined by simulated laboratory experiments. l34Cs was sorbed and desorbed on-from illite from aqueous solutions before and after the ilhte was coated with petroleum. Simulated connate water contained 0.001 M - 1.000 M NaCl was used in the experiment. The effect on desorption of cesium by 0.1 - 1.0 M KC1 solutions was also evaluated. The radiolabelled and coated illite samples were heated at 250 °C in different air conditions using normal air (containing O2) or Ni atmosphere. After the heating the effect on the stability of coating and the leachability of cesium was determined The desorption of cesium from illite increases with increasing temperature and increasing concentration of Na* and K*, the latter is more effective in removing cesium. Petroleum coatings on illite hinders the desorption of cesium, most effectively when the coatings occurred after cesium sorption, as thought to have occurred at Oklo. Heating in nitrogen atmosphere significantly decreased the cesium leachability from the petroleum coated illite comparing with the illite heated in air containing oxygen. Radionuclide desorption from clays is of interest to current radioactive \\ aste containment.

-120- P2-46

226Ra AND 210Po INTAKE IN THE POPULATION FROM BUCHAREST DURING THE PAST FIVE YEARS

Maria Toader, R. A. Vasilache Institute of Public Health 1-3 Dr. Leonte St., RO-76256 Bucharest, Romania

One of the effects of the pollution can be enhancing the natural radioactivity from the areas with pollution problems. Such an area is Bucharest, therefore a survey of the natural radionuclides in the environmental factors from this area should be performed with sustained periodicity. The paper presents the amount of ingested 226Ra and 210Po by the population from Bucharest, during 1992 - 1997. We have systematically measured food (cereals, milk and milk dairy, pork, beef and mutton, vegetables and fruits) and water samples. The results indicate a wide variance of 226Ra and 2WPo content from one type of foodstuff to another. The content varied from about 95 mBq/kg 226Ra in the eggs and 41 mBq in mutton, to 5 mBq/1 in milk or water. The 210Po content varied from 290 mBq/kg in spinach and 130 mBq/kg in fish, to 2 mBq/1 in water. This leads to an intake of 72.5 mBq/day 226Ra and 48 mBq/day 21

-121- P2-47

COLLOID CHARACTERIZATION IN A HUMIC-RICH ENVIRONMENTAL WATER WITH VARYING AMOUNTS OF URANYL IONS ADDED

Harald Z9nker, Gudrun Hflttig, Wolfgang Richter, Katja Schmeide and Heino Nitsche Forschungszentrum Rossendorfe.V., Institute of Radiochemistry

A procedure for the investigation of colloids in environmental waters rich in natural organic substances was developed. It includes microfiltration, ultraflltration, total organic carbon (TOC) analysis, uv-vis spectrometry, ICP-MS, alpha spectrometry, ion chromatography, photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM). The procedure is intended to provide a contribution to the colloid-chemical characterisation of mining waters from the abandoned East German uranium mines. It was tested on water samples from the Kranichsee mountain moor which is situated at the Czech-German border in the uranium mining area near Johanngeorgenstadt. First the submicron particles of the size class above 100 000 Daltons (about 5 nm) were studied by means of microfiltration, PCS and SEM. Particles of 20 to 300 nm were found in this size range. These particles contributed only a small mass fraction to the total concentrations of the organic and inorganic sample constituents. The colloid particles of the size class below 100 000 Daltons were characterised by ultrafiltration, i.e. the molecular weight distribution of the organics was determined. The influence of uranyl complexation on the humic colloid size distribution was studied by adding defined amounts of uranyl ions to the samples. Uranyl concentrations equivalent to about 5 % to 100 % of the humic proton exchange capacity of the humics were chosen.

-122- P2-48

ASSESSMENT OF SOME INDUSTRIAL POLLUTANTS AND THEIR IMPACT ON THE ENVIRONMENT

H.A. El-Naggar, M.K. Shehata and E.M. Metwally Atomic Energy Authority, Hot Lab. Center, Nuclear Chemistry Dept., P.O. Box. 13759, Cairo, Egypt.

The results obtained for the analysis of the raw materials and product samples collected from the three industries in Abu Zaabel area for the elements U, Th, La, Ce, Gd, Cr, Sb, Sc, Hf, Na, Fe Lu Zn and Au in the studied samples are given in this paper. U content (ppm) is found to be as follows: Phosphate ore = 72.6, GSSP - 50 45, SSP = 42.65, DCP = 8.36, Gypsum = 5.31 and GNPK = 4.664 (ppm). The La content of the phosphate ore is 40 0 ppm The Cr content in fertilizer products is in the range 12.12 - 19.56 ppm. except the gypsum sample which gives a value of 4.71 ppm. The DCP fertilizer has the highest value of Th, 3.25; while the gypsum has the lowest value 0.406 ppm. In alum company samples as well as Aracemco all the important elements have been analyzed either in the raw materials or in the products specially U, Th, Lanthanides as well as other elements using NAA. U,Ce,Co, La , Cr, ... etc content of the reference water samples are compared with two drainage water samples. Also.U Ce,Cr, and Th have been analyzed. All the elements content in the leaves samples collected from AZFC zone are higher than their values in the reference leaves sample of Mounofia. Also, the elements content of unwashed sample is higher than the values found in the same but washed sample. The measurements of the natural radioactivity in phosphate ore and in some fertilizer samples from AZFC are compared with the corresponding values obtained by NAA technique for the same samples. The comparison shows a negligible difference as regards the uranium content for each sample,

INEXT PAGE(S) Topic 3

ACTIVATION ANALYSIS AND OTHER RADIOANALYTICAL METHODS

Verbal presentations

-125- CZ9827788

THIRTY YEARS OF NAA DEVELOPMENTS AND APPLICATIONS AT THE THETIS REACTOR OF THE INSTITUTE FOR NUCLEAR SCIENCES, GENT

Frans De Corte" Laboratory of Analytical Chemistry, Institute for Nuclear Sciences, University of Gent, Proefluinstraat 86, B-9000 Gent, Belgium

The present location and basic infrastructure of the Laboratory of Analytical Chemistry at the Institute for Nuclear Sciences (INW) date from 1965 (with professor emeritus Julien Hoste as the director). The traditional instrumentation of the lab consists of i) the nuclear research reactor Thetis (1966) with 16 pneumatic irradiation facilities, mainly used for neutron activation analysis (NAA) and since the last ten years also for fission-track dating of geological materials, ii) an isochronous cyclotron (1977), used for CPAA, TLA, PIXE and the synthesis of labelled molecules for clinical research and applications, and iii) numerous rooms for radiochemical work and for radioactivity counting (with e.g. 13 detectors for high-resolution gamma- spectrometry). During the last decade this was complemented with machines for atomic spectrometry such as AAS, AFS, ICP-AES and ICP-MS. In addition, recently a lab was installed for the dating of archaeological materials and sediments with the thermoluminescence method. In this paper, a survey is given of the past and present fundamental developments and practical applications of NAA at the INW, which has always played an internationally appreciated pioneering role in this domain. Whereas the applications were mainly dealing with the analysis of semiconductors and high-purity materials, biomedical matrices, geological materials, environmental samples and artefacts, the developments were directed towards the elaboration of irradiation, separation and counting schemes, the determination of nuclear activation and decay constants, and especially towards the introduction of a user-friendly, modern (so-called ko-) standardisation method. The ko-methodology is nowadays applied in some 50 NAA-labs, was the subject of two International k0 Users Workshops (Gent, 1992; Ljubljana, 1996) and is commercially marketed by DSM Research (Geleen, The Netherlands) as the KAYZERO software package.

* Research Director of the Fund for Scientific Research - Flanders (Belgium).

-126- CZ9827789

APPLICATIONS OF NEUTRON ACTIVATION ANALYSIS IN DETERMINATION OF NATURAL AND MAN-MADE RADIONUCLIDES

Anthony R. Byrne and Ljudmila Benedik Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia

Neutron activation analysis (NAA), being essentially an isotopic and not an elemental method of analysis, is capable of determining a number of important radionuclides of radioecological interest with good precision and accuracy, by transformation into another, more easily quantifiable radionuclide. The nuclear characteristics which favour this technique may be summarized in an advantage factor relative to radiometric analysis of the original radioanalyte. Well known or hardly known examples include ^'U, ^U, ^Th, ^Th, 129I, 99Tc, a7Np and aLPa; a number of these are discussed and illustrated in analysis of real samples of environmental and biological origin. The advantages and drawbacks of this technique relative to conventional radiometric analysis and newer, mass spectrometric methods is also discussed. The value of NAA as an independent method in certification of radionuclide reference materials (where much remains to be done) is stressed. Where direct sample analysis is possible, NAA retains the important advantage of being essentially blank-free. Where preseparation of the analyte is necessary, some suggestions for improving the reliability of preseparation yields using internal, activatable tracers are proposed. The use of NAA to allow ^ U and B2Th to be used as endogenous (internal) radiotracers in alpha spectrometric analyses of uranium and thorium radioisotopes in radioecological studies is described, also allowing independent data sets to be obtained, of great value in quality control.

-127- CZ9827790

ACCURATE DETERMINATION OF TRACE ELEMENTS IN SEDIMENT CRMs BY INAA

Donald A. Becker Nuclear Methods Group, Analytical Chemistry Division National Institute of Standards and Technology Gaithersburg, MD 20899 USA

Accurate analytical data is crucial for the complete understanding of geochemical and environmental data as well as food and health measurements. In order to intercompare data between laboratories and/or countries, some fixed frame of reference is necessary, i.e., known or reference values. One important way to intercompare data is for all laboratories to analyze the same homogeneous, known reference material which challenges the analytical system in the same ways as the unknown samples of interest The use of natural matrix reference materials certified for elemental content as control materials in each analysis is one of the best ways to effectively accomplish this. A number of new sediment Reference Materials (RM) have recently been produced. An estuarine Standard Reference Material (SRM) 1646a was recently developed by the (U.S.) National Institute of Standards and Technology (NIST) and has been certified for elemental content. This material is a replacement for the original estuarine sediment (SRM 1646), which has been exhausted. In addition to the above SRM, the National Research Council of Canada has recently produced two sediments, the HISS-1 and PACS-2 Marine Sediments. My recent participation in certification analyses for these two CRMs provided different challenges due to their high sodium and contents. INAA is particularly useful for natural matrix reference materials such as sediments because of the capability for nondestructive analyses, and because of the well-understood errors and inherent accuracy of the technique. As a result, NAA has become one of the primary analytical techniques used for the certification of elemental content of NIST natural matrix Standard Reference Materials For the Estuarine Sediment, SRM 1646a, INAA was used to determine four elements (Al, Fe, Na, and Ti) at the percent concentration level, ranging from 0.45 to 2.3 % by weight. Six elements (Co, Cr, Mn, Sb, V, and Zn) were determined by INAA at the mg/kg concentration level, ranging from 0.31 to 235 mg/kg. Results from the other sediments were comparable The overall INAA analytical uncertainties for the four elements at the percent level (P=0.05) was 1.94 %. For five of the other six elements by INAA the average uncertainty (again at P=0.05) was 2.63 %. One element (Sb) had two values at 325 % and 195 % of the average from the other 10 values, suggesting a possible homogeneity problem for in that material. The final paper will include all INAA analytical values along with the control values, and will compare these to results from other techniques and with the final certified values, if available. Particular reference will be made to the potential errors and interferences noted during these analyses.

-128- CZ9827791

IRMM CERTIFIED REFERENCE MATERIALS AND ko-NAA: AN MPORTANT ROLE FOR THE FUTURE

P. Robouch, G. Arana, J. Pauwels, and S. Pomme* European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg, B-2440 Geel, Belgium *Belgian Nuclear Research Centre, SCKCEN, Boeretang 200, B-2400Mol, Belgium

The ko-Neutron Activation Analysis method was introduced at the Institute for Reference Materials and Measurements (IRMM) and the Belgian nuclear research centre (SCK-CEN) in 1994. This analytical technique is routinely used at IRMM for the production control, homogeneity and stability tests and/or for certification of metallic, biological and environmental reference materials. The successful implementation of ko-NAA was proven at several certification exercises - such as ISS Antarctic Sediment, BCR Mussel Tissue and BCR Bovine Liver, SMU Bovine Blood - where all our results were accepted for certification. Responding to regulatory and/or scientific demands, IRMM is collaborating with national institutes to develop new high quality reference materials: • in the field of Neutron dosimetry: high purity nickel, Al-Ag or Zr-Au-Lu alloys; • for environmental and industrial monitoring: Antarctic krill, doped plastics or catalytic converters; • synthetic multi-element standard for the accreditation of ko-NAA laboratories. Far from being exhaustive, this list highlights the important role that ko-NAA will play in the certification of reference materials in the years 2000.

-129- CZ9827792

REFERENCE MATERIALS: RECENT DEVELOPMENTS IN HEALTH, FOOD SAFETY AND ENVIRONMENTAL AREAS

Venkatesh Iyengar and Thomas E. Gills N1ST/SRMP Gaithersburg, MD 20899, USA

Efforts to minimize the environmental impact of pollutants, and concerns for health and food safety have enhanced the need for chemical analysis of environmental specimens and foodstuffs. In response to this, new analytical techniques have been developed and used to generate analytical information in many bioenvironmental systems. Simultaneously, this demand for analytical data has accentuated the need for routine, fast, and economic modes of analyses. In this context, certified reference materials (CRM) have proven to be indispensable tools for validating the measurement processes that are used for resolving public health issues. Clinical chemistry investigators recognized as early as the 1950s the need for analytical quality assurance and RMs. The decisive action in support of this came from the College of American Pathologists and the American Association of Clinical Chemists who introduced a series of standardization measures in the early 1960s that led to the development of control or standard materials to be used for calibration purposes. Cholesterol was the first such product (SRM 911) released in 1967. By 1979 the list of clinical SRMs had grown to 30, and as of 1997 there are > 70 biomedical SRMs issued by the NIST alone. These SRMs represent a broad spectrum of metrological excellence achieved for meeting the needs of clinical chemistry measurements such as accurate determination of calcium in human serum, reliable quantification of ultra trace elements in bovine serum, dependable identification of drugs of abuse in hair and urine, and elegant approaches leading to standards for DNA Profiling. In terms of metrological progress, these examples symbolize use of definitive methods, stringent control of contamination, streamlining of complex bioassays, and accomplishment of unique specificity, respectively. The initial efforts related to RMs for foodstuffs and environmental specimens can be traced back to 1965 with further improvements seen by 1975. In the 1980s, CRMs were gradually recognized as an integral part of analytical chemistry as effective tools to verify accuracy of the methods. Subsequently, new technologies emerged, and these were capable of processing complex materials without compromising matrix integrity and analyte stability over extended periods of storage The sequence of events can be outlined as follows: (1) improvements in inorganic methods of analysis, where nuclear analytical techniques played a crucial role, (2) identification of RM needs and assays for organic constituents in foods and environmental materials, (3) a clear understanding of the distinction between primary (certified) and secondary (e.g. check samples for proficiency testing) types of RMs, (4) preparing specific RMs (spiked standards) to address matrix related measurement problems, (5) preparation of slurry and composite (freeze dried and frozen) types of RMs, (6) realization of the need for a global vision in dealing with standards as illustrated by the activities of GESREM, (7) concern for traceability of chemical measurements to internationally recognized standards, and (8) recognition of the need for multidisciplinary approaches for preparing certain types of RMs (e.g. microbiological RMs) in response to the regulatory measurement needs of food safety and environmental health criteria.

-130- CZ9827793

COMPARING NEW TECHNIQUES FOR THE DETERMINATION OF MINOR AND TRACE ELEMENTS IN VOLCANIC GASES BY NAA

M. Bichler, C. Peltz, F. Sortino* Atominstitut der Osterreichischen Universitaten, Vienna, Austria *Istitulo di Geochimica dei Fluidi, Palermo, Italy

Minor and trace elements could be useful indicators of volcanic activity and the knowledge of their distribution contributes to a better understanding of degassing processes from various sources. The samples of volcanic gases were collected by means of alkaline absorption solutions at the fumarole fields of La Fossa volcano on the island Vulcano, Southern Italy. The outlet temperatures ranged from 300° to 600°. Ammonia solution and organic absorption media like tetraethylammoniumhydroxide and tris(hydroxymethyl)aminomethane were tested in addition to the conventionally applied 4M NaOH solution. A large number of minor and trace elements was determined by application of NAA, HPLC and AAS. For NAA, a new preparation technique including freeze drying was applied. In agreement with models proposed for the formation of the fumarolic gases we interpret the different concentrations of trace elements found as a consequence of mixing processes between magmatic fluids and hydrothermal gases. The positive correlations of metals and and the lower concentrations of these metals in gases with higher CO2 indicate their origin from a hydrothermal system. Furthermore, the strict distribution along a general trend as displayed by our samples suggests that a single hydrothermal source is involved in the mixing process. Nevertheless, we cannot exclude that other processes (i.e., gas-rock interaction, remobilization, changes in gas velocity, etc) could contribute considerably to the presence of trace elements in fumarolic gases.

-131- CZ9827794 INVESTIGATION OF SIZE-FRACTIONATED URBAN AEROSOL AND TRACE GASES IN BUDAPEST BY NUCLEAR-RELATED AND OTHER ANALYTICAL TECHNIQUES

I. Salma', W. Maenhaut2, E. Zemplen-Papp3 and J. Bobvos4 ' KFKI Atomic Energy Research Institute, Budapest, Hungary, ' University of Gent, Institute for Nuclear Sciences, Gent, Belgium, " Chemistry Seel. Hungarian Academy of Sciences, Budapest, Hungary, 4 Municipal Institute of Stale Public Health Officer Service, Budapest, Hungary

An air pollution study was conducted at two urban residential sites in Budapest (one representing the downtown, the other representing a wooded suburb) from 9 April till 17 May 1996. Size-fractionated aerosol samples were simultaneously collected on a daily basis, and meteorological conditions were recorded at both sampling sites. Stacked filter units (SFUs) with an upper size inlet cut-off were used as sampling device separating the urban aerosol into a coarse (about 10-2 ura equivalent aerodynamic diameter, EAD) and a fine (< 2 u.m EAD) size fraction. In addition, atmospheric concentrations of some criteria pollutants, e.g. NO, NO2, SO2, CO and the total mass of the suspended particulate matter were measured every half hour at one of the sampling sites by commercial equipment. The SFU filters were analyzed by gravimetry for the total particle mass, by a light reflectance technique for black carbon, by particle-induced X-ray emission analysis and instrumental neutron activation analysis for elemental composition (in combination for up to 40-45 elements). The analytical results were used for characterizing the levels and the multi-elemental composition of the urban aerosol at both sampling sites and for both size fractions, for investigating the atmospheric concentrations and diurnal variation of some criteria pollutants, and for comparing the time-trends of aerosols and trace gases. Identification of the major source types of the aerosol fractions and trace gases, and assessment of the relative contribution from these sources are to be accomplished by multivariate receptor modeling. The present paper reports on the status of the air pollution study, and gives a discussion of the results.

-132- CZ9827795

ANALYSIS OF AEROSOLS BY TWO NUCLEAR TECHNIQUES

V. Havranek, J. Kucera, J. Horakova, V. Vosecek Nuclear Physics Institute, 250 68 Reznear Prague, Czech Republic

Nuclear analytical techniques such as INAA (Instrumental Neutron Activation Analysis) and PIXE (Proton Induced X-ray Emission) are well suited for elemental analysis of various kinds of environmental samples, because low detection limits, a large number of simultaneously measured elements, simple sample preparation, and high accuracy of the results obtained are great advantages of these methods. Recently we have analyzed several sets of fine (particle size < 2.5 \xm EAD - equivalent aerodynamic diameter) and coarse (2 5-10 u.m EAD) atmospheric aerosol samples from the suburb of Prague and a rural location [1], high volume PM10 (<10 \xm EAD) aerosol samples, combustion aerosols [2] and water suspended paniculate samples, both by INAA and PIXE. Several advantages of analyzing the same sample by both methods have been proved. In this case, the number of measured elements is enlarged compared to INAA and especially the useful data for Pb, Si, and mostly also for S, are obtained by PIXE. Several elements, such as Al, K, Ca, Mn, Fe, Zn, etc., can be well determined by both methods. A comparison of results for these elemets can be used for quality assurance purposes and for estimation of sample homogeneity in cases where different parts of a sample are measured. Very good agreement between the PIXE and INAA results have been found for the fine aerosol particles. However, for the coarse particles and for thick samples of fly and bottom ashes a systematically lower concentrations were obtained by PIXE, especially for elemets with lower proton numbers. This difficulty can be overcome by introducing particle (grain) size corrections in the evaluation of PIXE results. The comparison of PIXE and INAA results for more complicated deposits (such as combustion aerosols) can be used for estimation of matrix correction in PIXE. Examples of the size particle effect and possible approaches for its correction are presented, as well as the final statistical evaluation of the results obtained, especially for aerosol analysis.

References

[1] J.Kucera, J.Santroch, J.Faltejsek, J.Horakova, V.Hnatowicz, V.Havranek, Air pollution monitoring in the Czech Republic by neutron activation analysis and other analytical methods, Report of the 2nd Research Co-ordination Meeting of the IAEA Co-ordinated Research Program on Applied Research on Air Pollution Using Nuclear-Related Analytical Techniques, Menai, Australia, 27-31 March 1995, NAHRES-26, IAEA Vienna, 1996.

[2] J.Smolik et al., Matrix and trace element behaviour in fluidised bed combustion of lignite, J. Aer. Sci., 28 (1997) S409-S410.

-133- CZ9827796

INAA AND CHEMICAL ANALYSIS OF WATER AND SEDIMENTS SAMPLED IN 1996 FROM THE ROMANIAN SECTOR OF THE DANUBE RIVER

A.I. Pantelica1, I.I. Georgescu2, M.H.I. Oprica2, CM. Borcia3 ^Institute of Physics and Nuclear Engineering "HoriaHulubei", PO BoxMG-6, 76900 Bucharest, Romania ^•University "Politehnica", Faculty of Industrial Chemistry, I Polizu Street, 78122 Bucharest, Romania ^Institute of Meteorology and Hydrology, Bucharest, Romania

Water and sediment samples collected during spring 1996 from 21 cross sections of the Romanian sector of the Danube river and the Black Sea coast were investigated for the major, minor and trace element content. Instrumental neutron activation analysis (INAA) at the WR-S reactor in Bucharest (neutron flux of 2.3xlO12 cm*2s"') has been used to find out the concentration of Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Dy, Eu, Fe, Hf, Hg, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Ti, Th, U, V, W, Yb, Zn, and Zr. Specific chemical methods used in geology were applied for the sediments to determine Si, P and the other major elements. The contents of chlorides, sulphates, bicarbonates, NH4+, NCb", NC>3' as well as the physical-chemical parameters of the Danube water sampled in the same time with the bottom sediments were determined. A mathematical model for the transport of the radionuclides by the Danube river from the entrance in Romania to the Portile de Fier (Iron Gates) dam was elaborated under the Research Contract RB-3260-IAEA- Vienna. Data concerning the solid discharge (kg/s), liquid discharge (m3/s), the time interval between the two measurements of the specific activity (Bq/kg) in the principal cross-sections, were taken into account together with the granulometric data and rugosity coefficients of the sediments. The present data are used to extend the mathematical model for the transport of the radioactive and chemical pollution by Danube river downstream to the Portile de Fier dam up to the Danube delta

-134- CZ9827797

DETERMINATION OF ELEMENTS IN CONCRETE OF A NUCLEAR ACCELERATOR TO DISMANTLE, BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS, ICPMS and ICPAES

A. Gaudry1, X. Bertho1, D. Piccot1, C. Fougeron2 'Laboratoire Pierre Sue, Centre d'Etudes de Saclay, bat 637, BP1 91191-Gifsur Yvette Cedex 2Laboratoire National Saturne, Centre d'Etudes de Saclay, BP1 91191-Gifsur Yvette Cedex

A particle accelerator at the Nuclear Centre of Saclay will stop working in the near future. The characterisation of the chemical radionuclides produced in materials irradiated by particles, including concrete used for the biological protection, is necessary in order to obtain the radioactive classification for the waste concrete. The distribution of radionuclides and their radioactivity inside concrete has to be modelled, using the characteristics of :1)- nuclear particle fluxes integrated all during the life-time of the installation, 2)-the chemical composition of the material and 3)-activation parameters of nuclear reactions produced by particles and secondary neutrons on elements, as well. This paper describes the techniques used for determining the chemical composition of trace elements radioactivated by neutrons and particles, but also the major elements which act upon the neutron penetration into the depth of the concrete. Major elements were determined using mainly, Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) for Si, Al, Fe, Mn, Mg, Ca, Na, K, Ti, P and Instrumental Neutron Activation Analysis (INAA) for AI, Mn, Fe, Mg, Ca, Ba, Na, K, and other specific methods for C, O, S, and H Trace elements were also determined using two techniques : Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and INAA. Fourty five elements were determined either by one of these methods or both. For INAA, various irradiation conditions were applied, enabling the determination of short- and long-lived radionuclides. When present, solid iron was separated by a magnetic bar after previous breaking of the concrete. The concrete was powdered to achieve a granulometry of less than 0 5 mm for INAA and then it was homogenized. Homogeneity was checked by INAA by means of the determination on 5 tests per sample on radionuclides with excellent counting statistics. Iron was determined separately by INAA. For the determinations by ICP-AES and ICP-MS, powders were previously fused by means of LiBCh, then dissolved in diluted HNO3 before analysis. A comparison between the results obtained, on the one hand, by ICP-AES and INAA, on the second hand, by ICP-MS and INAA revealed generally a very good agreement, making consistent analytical results.

-135- CZ9827798

COMPLETELY NON-DESTRUCTIVE ELEMENTAL ANALYSIS OF BULKY SAMPLES BY PGA.

Y.Oura, H.Nakahara, KLSueki, W.Sato, and T.Tomizawa* Department of Chemistry, Tokyo Metropolitan University "School of Literature, Keio University

A new non-destructive method is proposed for the elemental analysis of bulk samples. It is essentially a combination of PGA and NAA by a single neutron irradiation, and allows determinations of element contents of both major and minor constituents relative to that of some reference element. Major elements and some trace elements such as B, Sm, and Gd are mostly determined by the measurement of prompt gamma rays emitted when a bulky sample in its original form, namely, without any reduction of the sample size, is placed in the beam of neutrons guided from a nuclear reactor. Minor elements are then determined by the off-line measurements of gamma rays emitted from the radioactive nuclides produced within the sample by reactions. As the radioactivity remaining in the sample becomes negligibly small after a few weeks cooling, the proposed method will be most usefully applied for the elemental analysis of bulky precious samples such as archaeological samples, and arts and crafts. In this presentation, applicability of the method will be demonstrated for porcelain and bronze samples.

-136- CZ9827799

DETERMINATION OF RADON IN WATER - A COMPARATIVE STUDY -

T. L. Mobius*, S. Mobius**, E. Frenzel*** * Instilul National des Sciences et Techniques Nucleaires, University of Antananarivo, Madagascar **Research Center Karlsruhe, Germany "**Frenzel Consulting Instruments, Straubenhardt, Germany

The principles of measuring radon and its decay products in water are reviewed Methods and their reliability including emanation, filtering, diffusion for sample preparation and alpha-, beta-, gamma-counting and -spectrometry are surveyed and compared with modern liquid scintillation counting. Natural water samples with increased radon concentrations of 100 to 2000 Bq L"' have been analysed and the results compared. Liquid scintillation counting with alplWbeta-discrimination appeared to be among the most reliable ones and also most simple ones as regards sample preparation.

-137- CZ9827800

EXPERIENCE WITH NAA AND RADIONUCLIDES IN AN INDUSTRIAL LABORATORY

D.A.W. Bossus, R. van Sluijs DSMResearch Radioisotope Applications & Support P.O. Box 18 6I60MDGELEEN The Netherlands

Radioisotopes have been used in a wide variety of industrial applications since the early 1950s. At DSM, a Dutch chemicals and materials group, the first applications were introduced around 1955, when the company was still a coal mining enterprise. These applications, developed at DSM Research, mainly concerned on-line density measurements for process-control purposes. Process control is still the main field of application of radioisotopes in industry in general. Over the past thirty years many other industrial applications of radioisotopes have been developed. This has also been the case at DSM, which may be considered representative of the chemical industry. These applications have become indispensable tools and are nowadays used on a routine basis. The reason for this success is that these applications can be performed on-line without any interference with the production process and under normal production conditions. Besides process control, the following main applications of radioisotopes can be distinguished: - column scanning: a technique using sealed 60Co, 137Cs and 252Cf sources for on-line troubleshooting in distillation columns and other process equipment; this technique allows investigations to be performed at very short notice, saving production time and therefore money. - the radiotracer technique: used as a tool for troubleshooting, for flow measurements, for determining process parameters and for in-line corrosion studies This technique is a very helpful tool for technicians and researchers aiming to study and improve chemical processes. Short-lived radionuclides typically used in this field are S6Mn, 24Na, 82Br, "lmIn, 81mKr and ""Tc. The first three are neutron activation products, the last three are isotope generator products as used for medical diagnostics. - neutron activation analysis based on the ko-standardization method. The NAA technique, which was originally introduced for trace element analysis in high-purity silica, has evolved into a key analytical technique at DSM Research besides ICP-MS, ICP-AES and other sophisticated in- house methods.

-138- CZ9827801

PROGRESS IN SHORT-TIME ACTIVATION ANALYSIS

S.S. Ismail, R. Lauster, G.P. Westphal, F. Grass Atominstitut der Oslerreichischen Universitalen, Vienna, Austria

The sensitivity of determination of certain elements by short-time neutron activation analysis needs some improvements to gain a better counting statistics in the measurement of the relevant radionuclides by gamma-ray spectrometry. This can be attained by various means: 1) Using a higher neutron flux, eg. by activation in a rector pulse (the neutron flux may increase by a factor of 1000). This, however, only increases the sensitivity for elements forming very short-lived radionuclides (with half-lives shorter than 1 min), such as 8Li, 12B, 20F, 89mY, 207mPb); 2) Pseudocyclic and cyclic AA allow an increase of sensitivity by increasing the signal (peak area), but these techniques are restricted to samples of low matrix activation; 3) Shielding of the thermal neutrons diminishes the matrix activity distinctly, enabling longer irradiation, and thus allowing, e.g. the determination of 33 elements in N1ST-SRM 1633b Coal Fly Ash. 4) Increasing the througput of the measurement system by using a digital preloaded amplifier of a new design. 5) Increasing the detector efficiency by a factor of about 10 by means of a HPGe well-type detector. 6) Lowering the Compton continuum by a Compton suppression system. 7) Activation of samples pre-separated by fast separation methods. Examples of these techniques will be demonstrated.

-139- CZ9827802

THERMOCHROMATOGRAPHY AND ACTIVATION ANALYSIS

G.S. Sattarov, A.A. Kist Institute oj Nuclear I'hysics, Tashkent, Ulughbek, '02132, Uzbekistan. CIS

Despite of many possibilities to perform activation analysis in a non-destructive mode, in many cases pre-concentration or radiochemical separation is necessary due to a low concentration of elements to be determined and interferences from matrix elements. Difficulties in decomposition (dissolution) of some kinds of samples is a very important limitation In some fields of inorganic chemistry gas-thermochromatography is used very successfully. It is a promising method in neutron activation analysis, too. The procedure includes heating of irradiated samples in the stream of a reacting-carrying gas (air, chlorine, etc.) or heating in the presence of compounds liberating the gas at a high temperature (AJCb). Gaseous products pass through the tube with a certain temperature gradient, which is filled with various sorbents, and condense in different parts of the column. In this technique, sample decomposition and element separation are carried out in a single step. Studies of the processes of producing and trapping of volatile compounds allowed to elaborate various types of sorption tubes of varying length and temperature gradient, various filters, sorbents, etc. Efficiency of element extraction from samples (rocks, ores, etc.) by transformation into volatile compounds reached 90-99% (As, Se, Mo, Sb, Re, Os, Ir, Hg). The element detection limits of these methods are significantly better then in INAA. The most important advantage of the method is the possibility of determination of some noble metals determination in geological samples that are difficult to decompose.

-140- C29827803

FAST NEUTRON ACTIVATION ANALYSIS-FNAA USING d(13MeV)+Be REACTION AT THE BUCHAREST CYCLOTRON

B. Constantinescu and Roxana Bugoi Cyclotron Laboratory, Institute of Atomic Physics POBMG-6, Bucharest, Romania

At the Bucharest U-120 classical variable energy Cyclotron, intense fast neutron beams are produced using deuterons accelerated up to 13.5 MeV, bombarding a thick (166.5 mg/cm2) target. Using time-of-flight (TOF) measurements and the multiple foils method (activation detectors and fission chambers), an absolute flux intensity of 6.63x1018 n/cm2nC and an average energy of the neutron spectrum of 5.352 MeV have been determined. Neutron energy spectra for free air and an irradiation space (a 0.02 m thick walled wooden box, 0.3x0.3x0.3 m3, surrounded by 0.5 m of paraffin and placed on a 0.7 m limonite concrete pedestal base) are presented. In the frame of our archaeometrical programme for Byzantine objects (coins, glasses, ceramics) we used FNAA as a complementary method to XRF (X-Ray Fluorescence), PIXE (Particle Induced X-ray Emission) and PIGE (Particle Induced Gamma-Ray Emission). FNAA is a non-destructive bulk analytical tool and the objective is to determine some light elements (Na, Mg, Al, Si, K), to solve the problem of interference (X-rays) in the case of As-Pb, and to explore its possibilities for the determination of other major, minor and trace elements. We irradiated some Cu and Pb coins, glass and ceramics samples placed at 5 cm behind the Be target for 100 minutes with a current beam intensity of 8-9 u.A (Q=50 mC, corresponding to 5xl012 n/cm2). The radioactivity was measured in two stages: after 30 min. cooling time Si, Al, Mg, K are determined and after 72 h cooling time the rest of radioisotopes. We used an Ortec HPGe detector (1.9 keV resolution at 1332.5 keV and 25% relative efficiency), connected to a 8192 channel Spectrum 88 MCA. The samples were placed at 3-5 cm in front of the detector. Because of the broad energy spectrum, nuclear reactions such as (n,y), (n,2n), (n, p), (n,a) are easily produced but the interferences must be considered. The threshold values for (n,2n) reactions are of the order of 10 MeV and in accordance with the fact that there are very few neutrons with such a high energy, we observed the reaction only on Ca, As, Ag, Sb. For the Cu coins we detected radioisotopes from Fe, Ni, Cu, Zn, As, Ag, Sn, Sb, Pb; for the Pb coins: Fe, Cu, Zn, As, Ag, Cd, In, Sn, Sb, Pb (interference In-Sn, Cd-ln), for ceramics: Mg, Al, Si, K, Ca, Ti, Fe, Zr, Ba, Ce (interference Mg-Al-Si, Y-Zr) and for glass: Na, Mg, Al, Si, K, Ca, Fe, Cu, Zn, As, Ba, Ce, Pb (interference Na-Al, Al-Si). The precision of our results is in the order of 15 to 25% relative error. For our conditions, the detection limits are in the range of 30 ppm (Ni, As, Sb) to 200 ppm (Ti, Fe, Zn, Sn, Ba, Pb) for trace elements, and in the range of 0.2% to 1% for major light elements These detection limits were tested using NBS geological standards (Wl, BM, KH). To distinguish groups of coins, ceramics or glasses of similar composition, FNAA is always used in combination-with XRF and PIXE. A typical composition obtained for a local 3rd century BC vase is: SiO2=63%, A12O.,=9%, MgO=2.2%, CaO=8.5%, K2O=3.9%, TiO2=0.2%, MnOO.06%, Fe2O3=3.5%, Zr=150 ppm, As=50 ppm, traces of Sr (<30 ppm), Ba=I000 ppm, Ce=150 ppm, La=60 ppm, Nd=50 ppm, traces of Eu, Gd (<20 ppm). A comparison with composition of other ceramics (Balkans, Asia Minor) was used to explain various commercial aspects (e.g. maritime connections in the Black Sea).

-141- CZ9827804

PETROCHEMICAL STUDY OF THE JABAL HAMOMAH ROCKS USING INAA AND XRF METHODS, KHAMIS MUSHYAT AREA, SW SAUDI ARABIA

Ahmed A. Almohandis Department of Geology, College of Science, King Saud University, Riyadh, Saudi Arabia

The Jabal Hamomah intrusion is a small circular shonkonite body. It is a cone-like mass with highly fractured rocks, and it is highly altered at the base. The intrusion consists essentially of augite, k-feldspar, with varying amounts of olivine, biotite, Fe-Ti oxides and minor apatite. Instrumental neutron activation and X-ray fluorescence methods were employed to study the petrochemical features of the intrusion. The results show that the rocks are characterized by a low content of SiC>2 similarly to basalt, but with relatively high alkalies. SiC>2 and Fe2C>3 increase slightly towards the top of the intrusion. Ba, Rb, Sr, Zr. Y and Sc also show an increase towards the top, while Cr, Cu, Ni and V show an increase towards the base of the intrusion. Neutron activation analysis of the representative sample from the intrusion shows a concentration of La, Ce, Eu, Sm, Yb and W. Such elements reside preferentially in minor accesory phases, especially apatite, not in major minerals.

-142- CZ9827805

A RE-EXAMINATION OF COINCIDENCE AND GAMMA-PEAK DOUBLET HANDLING IN KAYZERO-BASED NAA

Stijn Van Lierde12, Frans De Corte1, Daniel Bossus2, Robbert van Sluijs2 ' Laboratory of Analytical Chemistry, Institute for Nuclear Sciences, University of Gent, Proeftuinstraal 86, B-9000 Gent, Belgium ' DSM Research, POB 18, NL-6160MD Geleen, The Netherlands

Recently, a project was initiated aiming at the upgrading of the DSM KAYZERO/SOLCOI [I] software package developed for use in ko-startdardised neutron activation analysis [2]. The project topics considered are: corrections for true-coincidence, the automatic handling of peak-multiplets, the extension of the nuclear data library with re-measured k0 and Qo values, the generalisation of the implemented mother-daughter relations and the correction for fission and threshold reactions. In the present contribution, results are reported on the first two topics mentioned above. An improvement of true-coincidence correction was achieved for a number of analytically important cascade gamma lines of about 20 elements including Fe, As, Zr, Mo, Ag, Sb, some rare earth elements, Ta, W, Pt and U. Therefore, decay schemes were analysed with respect to the relevance of the coincidences, followed by a selection of the most recent decay scheme data from the literature. In case the accuracy of the calculations was doubtful, an experimental check of the coincidence correction was performed. For some radionuclides, ko-factors of analytically relevant gamma lines present in multiplets (in most cases doublets) were formerly not available. Hence, problems existed with the automatic computer-assisted conversion of peak areas to analytical results. Therefore, re-measurement of the individual ko-factors was performed by using up-to-date high resolution Ge-detectors. This study involved a number of gamma lines of radionuclides for the determination of some 10 elements including Mo, Pd, Ag, Eu and U. This now leads to the elimination of important gamma-spectrometric errors. The present project will be continued by handling the other topics mentioned above and the results will be reported in due course.

References [1] KAYZERO/SOLCOI User's Manual (version 4), DSM Research, Geleen (NL), December 1996. [2] F. De Corte, A. Simonits, F. Bellemans, M.C. Freitas, S. Jovanovis, B. SmodiL, G. Erdtmann, H. Petri, A. De Wispelaere, i. Radioanal. Nucl. Chem., 169 (1993) 125.

-143- CZ9827806

CALIBRATION OF THE REACTOR NEUTRON SPECTRUM FOR THE ko-NAA STANDARDIZATION USING SEVERAL APPROACHES

J. KuCera1, M. Marek2, F. TomaSek2, J. Frana'Z. Horak1, L. Viereibl2 'Nuclear Physics Institute, CZ-250 68 kez near Prague, Czech Republic 2Nuclear Research Institute kez, pic, CZ-250 68 kez near Prague, Czech Republic

Of the comparator methods in NAA, the ko-standardization has been recognized as a fully operational analytical tool, because its fundamentals are fully understood and have been verified by independent experiments [1], and because several software packages, such as KAYZERO/SOLCOI [2], have become available. In the ko-NAA standardization, several parameters are experimentally determined. A calibration of the reactor neutron spectrum involves the determination of parameters /and a (/= thermal (subcadmium) / epithermal neutron fluence rate and a is a parameter taking into account the non-ideality of the epithermal neutron fluence rate distribution by the approximation \/El+a). For the a determination, the Cd-ratio, Cd-covered or Zr-Au bare triple-monitors methods can be used, while the / determination can be accomplished by the Cd-ratio for the multi-monitor method and the bare Zr bi-isotopic monitor method [1]. An alternative is to evaluate the/and a parameters from the complete neutron spectrum reconstruction. For this purpose the SAND II programme [3] with the library of activation cross sections SNL RML [4] was employed. For estimating the input spectrum, the library of spectra of the programme SAND II and the Monte- Carlo calculation using the programme MCNP [5] for a model of the reactor LWR-15 of the Nuclear Research Institute Rez, pic. were used. The nuclear reactions contained in the DOSCROS, IRDF and some other cross section libraries were employed which have been completed for Zr reactions Activity measurements were performed using two y-ray spectrometric systems of NPI and NRI Rez and the results obtained using the above approaches were compared

References [1] F. De Corte, A. Simonits, Vade-mecum for ko-Users, DSM Research, Geelen, The Netherlands, R94/11492, December 1994. [2] R. van Sluijs et al., KAYZERO/SOLCOI software package (Version 3.0), DSM Research, Geelen, The Netherlands, R94/11492, December 1994. [3] M. Marek, PC Version of SAND II Code, NRI 9451 R,D, Rez, September 1991. [4] P.J. Griffin, J.G. Kelly, T.F Luera, J. VanDenburg, "SNL RML Recommended Dosimetry Cross Section Compendium", SAND92-0094, RSIC DLC-178, November 1993. [5] J Briesmeister (Ed), "MCNP - A General Monte Carlo N-Particle Transport Code Version 4A", LA-12625-M, November 1993.

-144- CZ9827807

THE WELL-TYPE SEMICONDUCTOR DETECTOR HARNESSED

Menno Blaauw Interfaculty Reactor Institute, Meketweg 15, 2629 JB Delft, The Netherlands

The well-type semiconductor detector has been around almost as long as the coaxial semiconductor detector. Even though it has important advantages over the coaxial detector, the drawbacks have been severe enough to very much limit the use of these detectors. The high sensitivity (e.g. 50 % at 100 keV, 10 % at 1000 keV) of a well-type could be achieved with a modern, large coaxial crystal with the sample on the end cap, but in that set-up the geometry becomes a crucial source of error for the coaxial detector, whereas the well-type's efficiency hardly depends on the counting geometry at all. The severity of the coincidence summing effects has rendered it impossible in the past to calibrate a well-type detector with a standard calibration source and use the efficiency curves obtained for other radionuclides. The popular approach to this problem, where the detector is characterised with a measurement in a "reference position" and efficiencies for other geometries are obtained through computation is invalid for the well-type case. Since 1992, a method has been under development at IRI to characterise a well-type detector using a peak efficiency and a peak-to-total efficiency curve, and compute radionuclide specific counting efficiencies from those curves for "real" peaks as well as for "sum" peaks. Recent improvements to this method have demonstrated that now, a well-type can be as easy to calibrate and operate as a coaxial detector, once the software is in place. In this paper, the calibration method will be described and examples of results given. It will also be shown just how severe the errors are that can be made when coincidence summing is neglected, for a few typical INAA and environmentally relevant radionuclides

-145- CZ9827808

SELF-ATTENUATION FACTORS IN GAMMA-RAY SPECTROMETRY

Matjai Korun Jozef Stefan Institute, Jamova 39, Ljubljana, Slovenia

The sample material influences the counting efficiency in X-and gamma-ray spectrometry via the self attenuation factor [1]. This factor describes the amount of radiation emitted in the sample and prevented from registration in the full-energy peaks by absorption within the sample:

= ev(0,E) where ev(m,E) denotes the counting efficiency of an extended sample with attenuation coefficient m at the energy E. It follows from the definition that the self-attenuation factor at zero attenuation assumes the value of 1. In addition to that, the derivative of the self-attenuation factor with the attenuation coefficient for small self attenuations is equal to the average path of gamma-rays in the sample. Approximations of attenuation factors in the form of analytical expressions have been proposed for planar geometries [1] and [2], for Marinelli geometry [3] and for well-type geometry [4] as functions of the attenuation coefficient and sample dimensions. All factors have been derived assuming a one-dimensional gamma-ray transport model. The self-attenuation factors can be expressed instead as functions of sample dimensions as expressions for average path in the sample of gamma-rays, registered in the full-energy peaks. This approach has the advantage that values of the average path, derived from spectral data, can be used in the attenuation factors, allowing the application of attenuation factors to samples of arbitrary shapes. Various analytical expressions as approximations to self-attenuation factors will be discussed. Their values obtained from average paths are compared to values of self-attenuation factors obtained from Eq. (1) where measured and calculated efficiencies will be used..

References:

K. Debertin, R. G. Helmer, X- and Gamma-Ray Spectrometry with Semiconductor Detectors, North Holland, Amsterdam, 1988. K. M. Miller, Nucl. Instr. and Meth. A, 258 (1987) 281. P. Dryak, K. Kovar, L. Plchova, J. Suran, J. Radioanal Nucl Chem. Lett. 135 (1989) 281 Sima, Health Phys. 62 (1992) 445 P. G Appleby, N Richardson, P. J. Nolan, Nucl Instr. and Meth. B 71 (1992) 228.

-146- CZ9827809

COINCIDENCE SUMMING CORRECTIONS FOR NATURAL RADIOACTIVITY MEASUREMENTS USING A MARINELLI BEAKER DETECTOR SETUP

S.J.Gelscma, M.BIaauw hiterfaculty Reactor Institute, Delft Technical University Delft, The Netherlands

The measurement of low-level radioactivity, for example the measurement of natural radioactivity, requires a detector setup that allows a great amount of sample material to be positioned at a small distance from the detector, such as a Marinelli beaker setup. Although Marinelli beakers have been used for several decades, it has proven to be very hard to obtain accurate measurement results, especially when the effects of the absorption of gamma-rays within the source are combined with the effects of coincident summing. Very recently, we developed a method for accurately measuring in a Marinelli beaker nuclides that emit coincident gamma-rays. Apart from the two conventional curves for peak efficiency and peak-to-total values, the method uses a third curve that describes the variation of the peak efficiency over the source volume. The use of this third curve is crucial to the method. We will discuss the method developed, show how the method is to be used in practice, and prove the validity of the method. In addition, we will use the method to calculate the magnitude of the coincidence corrections for most natural radio-nuclides measured in a typical Marinelli beaker setup The results will show that, in general, the coincidence effects for these nuclides can easily be underestimated.

-147- CZ9827810

PULSE-SHAPE DISCRIMINATION TECHNIQUE IN RADIOANALYTICAL METHODS

Jiri VaciV, Severin Posta\ Vladimir Hnatowicz", and Jarmila Cervena" "Nuclear Physics Institute, 250 68 Rei near Prague, Czech Republic bNuclear Research Institute, pic, 250 68 Rei near Prague, Czech Republic

Several successful techniques have been developed to eliminate unwanted background level in experimental radiation spectra. One of the background-reduction techniques is pulse-shape discrimination (PSD) which is based on the fact that different particles or quanta give rise to different spectrometer response, i.e. to different signal shapes. The shapes can be recognized and analyzed by appropriate electronic circuits which can measure either the rise time or the fall time of the pulses. The PSD technique has been suggested for different particle/background separations (such as n/y, a/y, a/proton or a/electron separations). It has been successfully applied i.e. in separation of (fast) neutrons from intensive gamma background or charged particles from gammas. Recently the principle of the PSD has been applied in the construction of special ORTEC and CANBERRA spectroscopic modules. In this study we have employed the principle of PSD in two different radioanalytical methods developed in the Nuclear Research and Nuclear Physics Instuitutes in Rez. One of the methods concerns with the determination of uranium by delayed neutron counting (DNC), the second method is known as neutron depth profiling (NDP). An effective elimination of unwanted background signals in measured radiation spectra has been proved At least two orders of magnitude of background level suppresion has been achieved independently of employed PSD circuits. The PSD technique has substantially improved detection limits of the DNC and NDP facilities

-148- CZ9827811

DETERMINATION OF RADIOACTIVE TRACE ELEMENTS IN ULTRA LOW LEVEL DETECTORS BY MEANS OF NEUTRON ACTIVATION ANALYSIS

R. v. Hentig, T. Coldbrunner, G. Angloher, F. v. Feilitzsch Physics Department El5, Technical Universityl Munich, 85 748 Garching, Germany

New analytical methods for the determination of naturally occurring radionuclides are pre- sented. Combining neutron activation, radiochemical separation and coincidence counting tech- niques yielded detection limits of the nuclides investigated lower than 10"!4 g/g for Th, U, La and lower than 10'12 g/g for Cd, In, K, Lu, and Rb in complex matrices, such as organic liquids and silicon. The P~y coincidence counting techniques employed for the determination of U, Th and Lu in the ultra-trace region are discussed in detail, the recorded spectra and selection criteria applied for the evaluation of decay events are presented. Impacts of the results on low level experiments in the field of astro- and particle physics are discussed as well as the advantage of neutron activation analysis being sensitive to most naturally occurring radionuclides.

-149- CZ9827812

THE MEASUREMENT OF NATURAL RADIOACTIVITY AND THE IMPACT ON HUMANS

A. Faanhof Atomic Energy Corporation of South Africa Ltd., P.O.Box 582, Pretoria, SOUTH AFRICA

In the Republic of South Africa the generation of nuclear power compared with the use of fossil fuel, mainly coal, is relatively modest. They have only one power plant situated at Koeberg near Cape Town in the south with a maximum capacity of 2 x 900 MW. Besides this, a small nuclear research reactor at the Atomic Energy Corporation (AEC), Pelindaba, near Pretoria in the north, is operated at a maximum power of 20 MW. The AEC formerly enriched its own uranium and manufactured fuel elements both for the Koeberg and Pelindaba sites. Nowadays, the research reactor is mainly used for production of medical and industrial isotopes, colour modification of gemstones, neutron diffraction for industrial applications and neutron activation analysis. Natural radioactivity goes with the vast mineral resources in such concentrations that the nuclides from the natural uranium, thorium and actinium decay series are found to pose concern for occupational exposure at certain mining and mineral processing industries, and public exposure to communities living around these areas. The main industries concerned are the gold, copper, heavy mineral sand and the coal mining and processing operations. The radiological impact of all operations is monitored as part of the license obligations, imposed by the South African Nuclear Energy Act. The Council for Nuclear Safety is mainly concerned about the impact on workers and the release of effluents and dust to the environment, while the Department of Water Affairs & Forestry is intensively studying the concentration of radionuclides in identified catchment areas around the mining and mineral processing industries to assess the impact on the public using these water sources as part of their dietary intake. The occupational exposure at the Koeberg Nuclear Power Station showed an average value of about 0.90 mSv for the years 1994 and 1995. Liquid and gaseous effluents discharged from this plant in 1995 resulted in a calculated radiation dose to the public of about 0.45 ftSv per year. Data for the operation of the AEC site showed an average occupational exposure of 0.59 mSv for the year 1995, while the public exposure due to airborne effluent discharges was calculated at a maximum of 12 uSv per year for 1995. Compared with the nuclear industry, the occupational and public exposure imposed by the mining and mineral processing industries is more difficult to assess due to the many potential transport mechanisms and pathways of the natural radioactivity Preliminary data show that occupational exposure due to inhalation of respirable dust could be substantial if no proper preventions are made. Yearly doses could be as high as 20 to 40 mSv per year in certain areas of the uranium, copper and heavy mineral processing industries. Recent monitoring of surface and borehole water in two catchment areas around the major goldmining activities revealed that public exposure could accumulate up to a few mSv per year, if these were the main sources of drinking water available to the communities living in and around this area. Assessment of the yearly dose from the natural radionuclides of the uranium, thorium and actinium series poses a major challenge to the Radioanalytical Laboratories of the Atomic Energy Corporation of South Africa. In total some 36 individual nuclides which all have their own individual dose conversion factor should be assessed In practice, after assuming radioactivity equilibrium between the very short lived daughters and their respective parents, one has to analyse about 10 to 15 long-lived nuclides. The analytical sensitivity required differs vastly from nuclide to nuclide and matrix to matrix. All nuclides have their individual dose conversion factor, which is

-150- also age related, and the total dose received depends on the yearly intake via ingestion or inhalation. The generally accepted first order assessment is based on certain default intake values, and a dose screening level of 25 u.5Sv per year per individual source of intake. Some of these nuclides, like elemental uranium and thorium, are determined with instrumental neutron activation analysis or ICP-MS, followed by calculation of the U-238, Th-232 and U-235 nuclide activity. However, most of the natural radionuclides require radiochemical separation, concentration and determination procedures. The matrices normally concerned are drinking water, foodstuffs and respirable airborne dust. They all require an individual approach to analyse their natural radionuclides. For drinking water and milk the Radioanalytical laboratory should be able to analyse nuclides like Ac-227, Pa-231, Th-230, Ra-226, Pb-210, Po-210, Th-232, Ra-228 and Th-224 at levels of about 1 to 5 mBq/L. For certain foodstuffs one is faced with a required sensitivity of 0.1 to 5 mBq/kg, which poses problems with adequate sample dissolutions to allow radiochemical separations. Usually direct measurements by y-ray spectrometry are not adequately sensitive to assess the yearly dose. With respirable airborne dust one faces the problems of limited sample quantities. This requires a specific analysis protocol, which again places severe constraints on the turnaround time of the analyses. All these factors, together with the economic requirement to produce large quantities of data at low costs challenges the capabilities of our Radioanalytical laboratories. An overview will be presented of the regulatory yearly dose restrictions, the translation into routine radioanalytical requirements and how we manage and what we do to fulfil the needs of the Southern African market.

-151- CZ9827813

THORIUM: DETERMINATION IN BRAZIL

Maria Angela de Barros C. Menezes and Claudia de V. Schayer Sabino Centro de Desenvolvimento da Tecnologia Nuclear/CDTN Comissao National de Energia Nuclear/CNEN Caixa Postal 941 - CEP 30123-970, Belo Horizonte - MG - Brazil e-mail: [email protected], fax: + 55 31 499.3380

The reactor TRIGA MARK I IPR-Rl started working in November 1960. This research reactor is located at Centro de Desenvolvimento da Tecnologia Nuclear/CDTN (Nuclear Technology Development Centre), Belo Horizonte, Brazil. Since its start-up, the reactor has been fulfilling several objectives including working as an important tool for analytical purposes. At the end of the sixties, the CDTN developed analytical techniques to determine uranium and thorium in pyrochlore (ore of , a complex oxide of calcium, sodium and niobium where rare earth and metals may be present) in answer to requests for exportation. Uranium was determined by means of delayed fission neutrons and thorium by means of X-ray spectroscopy. Uranium prospection and the occurrence of thorium resulted in an increasing analytical demand. Volumetric, gravimetric, colorimetric and X-ray methods were applied to determine thorium in minerals and ores, but to determine trace levels in leaching solutions and residues, it became necessary to use the neutron activation technique that had been used to determine other elements. Determinition of thorium in environmental samples such as surface and drinking water, plants and air filters was necessary in the seventies for the radiological control. The Brazilian soil is rich in thorium, with monazite, the most important primary source of the metal, containing on an average ca. 6 per cent. The environmental control programmes in mines and nuclear facilities co-ordinated by the CDTN improved the analysis diversifying the matrices: pasture, soil, air filters, biomaterials. In 1980 the determination of 228Th and 230Th by means of radiochemical separation methods followed by alpha spectrometry was established for groundwater, drinking and surface water and air filters. This paper describes the radiochemical procedures that have been carried out to determine 2'2Th by means of instrumental and radiochemical neutron activation analysis in several matrices as well as the determination of 228Th and 2'°Th by alpha spectrometry, answering the analytical demand. Some detection limits that have been reached are, for instance, 0.02 Bq L"1 for 232Th and 0.05 Bq L"' for 228Th and 2TOTh in groundwater, drinking and surface water. Radiological aspects are emphasised. The CDTN has been giving attention to the precision and accuracy of the methods in accordance with the general tendency towards increased sensitivity of methods used to determine trace quantities of thorium isotopes, by analysing reference materials and participating in intercomparison programmes. In Brazil, the occurrence of these radioisotopes is important not only in mines and nuclear facilities but also in the environment, where the radioisotopes may be present in water, soil, everywhere, including agricultural and animal production.

-152- DETERMINATION OF ^Rn CONCENTRATIONS IN LITHUANIAN SPA WATERS BY LIQUID SCINTILLATION COUNTING

A. Mastauskas, R. Ladygiene, K. Gasiunas Radiation Protection Centre, Ministry of Health, Vilnius, Lithuania

The objectives of this study were to determine the concentrations of 222Rn in Lithuanian spa waters and to compare the measured radon concentrations in spa waters with those in underground waters with a small content of minerals and in waters of private wells. The measurements have been performed for 34 spa water sources in four different places of Lithuania by liquid scintillation method (Prichard and Gesell 1997; Horton 1983). The Packard Liquid Scintillation Analyser Tri-carb 2770 TR/SL and Packard BioScience cocktail Insta-Fluor have been used. The measured spa water sources differed in content of mineralization and in the depth of sampling. An influence of the sampling conditions, sampling time, and conditions of the preparation of samples on results of counting is presented. Extraction of 222Rn from water samples with a high mineralization level in toluene in order to prevent precipitation in a mixture with the organic scintillation cocktail is discussed. Details of optimization of measurements of low radon levels are presented. A comparison of two methods of liquid scintillation counting and the use of the E-Perm electret system ( Electret Radon Monitor, Rad. Elec. Inc. USA) has been performed. The arithmetic and geometric means of radon concentrations in water in some Lithuania areas are presented.

References

Prichard, H. M.; Gesell, T. F. Rapid measurements of222 Rn concentration in water with a commercial liquid scintillation counter. Health Physics. 33 : 577-581; 1977 Vitz, E. Toward a standard method for determining waterborne radon. Health Physics. 60 : 817-829; 1991

-153- CZ9827814

DETERMINATION OF 90Sr IN ENVIRONMENTAL SAMPLES BY MICROWAVE ASSISTED DIGESTION - CHROMATOGRAPHIC SEPARATION

J.M. Torres, M. Llaurado and G. Rauret Dept. de Quimica Analitica, Universilal de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain

Following the Chernobyl Nuclear Power Plant accident, concern about the radioactive contamination of the environment by %Sr has increased considerably, since it was a main fission product in such event and has a relevant contribution to the internal dose. Three stages are involved in the determination of '"Sr in environmental samples: sample attack, radiochemical separation (of both MSr and its progeny '"Y) and finally measurement. The most time-consuming step is sample dissolution, usually performed by acid attack, given that nowadays radiochemical separation can be easily performed: by liquid-liquid extraction procedures in the case of 90Sr, and with immobilised crown ethers in resins in the case of'"Y. New instruments with very stable and ultra-low-level background allow now to use significantly shorter measurement times For the determination of wSr, the introduction of microwave-assisted digestion methods has improved acid attack by drastically decreasing both digestion time and the volume of acidic reagents. Recent studies describe many applications of microwave-assisted methods for the determination of inorganic and organometallic compounds in several matrices. We have recently studied the microwave-assisted digestion of soils for the '"Sr determination, one of the firsts papers dealing with microwave digestion of radionuclides (J.M. Torres et al., Analytica Chimica Acta, in press). The presented work extends the application of microwaves for the '"Sr determination to other environmental samples such as sediments, vegetation and milk. An open-focused microwave system, which accepts large samples intakes usually required for radioanalytical chemistry due to the low level content of radionuclides in environmental samples, was used This system can handle up to 10 g of sample intake which, in many cases, is enough to have acceptable limits of detection. Different digestion procedures are optimised for each matrix studied, paying special attention to the microwave power, the time of digestion and the volume of acidic reagents Once the sample is in solution a new separation procedure using a specific resin —Sr. Spec— is applied and the measurement is performed by liquid scintillation. The results obtained are compared with a previously optimised method based on liquid-liquid extraction of ""Y and Cerenkov radiation measurement. Microwave-assisted digestion of environmental samples, together with the application of new separation procedures, proved to be very good mean for ""Sr determination in environmental matrices, shortening the analysis times, lowering the amount and number of acids to be used. Moreover, the automated instrumentation requires less supervision by the analyst.

-154- CZ9827815

RAPID MEASUREMENT OF RADIATION CONCENTRATION BY LOW-LEVEL AIR-BORNE SPECTROMETRY

Chien Chung Department of Nuclear Science, National Tsing Hua University Hsinchu 30043, TAIWANR.O.C

In order to perform rapid determination of radioactive concentration in air near ground level as well as of the cosmic electromagnetic radiation dose rate in-flight, a portable, battery-powered gamma-ray spectrometer equipped with a Nal(Tl) detecting probe was used and carried by the UH-1H helicopters and C-I30H planes of the Armed Forces of the Republic of China on Taiwan. The spectrometer was calibrated using a volumetric source of radioactive rare gas nuclides prepared by the irradiation of stable isotopes in the nuclear reactor. The radioactive gas consisting of Ar, Kr, and Xe of known intensity was dispersed in a sealed calibration hangar, and the spectrometer was positioned therein in order to acquire the absolute detection efficiency for the measurement of the concentration of radioactive air-borne contaminants near the ground. To conduct aerial survey, the gamma-ray spectrometer, neutron counter, radiation dosimeter, and the global positioning system were installed onto the Air Force C-130H transport plane which can fly up to 16,000 ft in designated course around Taiwan, and onto the Army UH-1H utility helicopter for contour flight. On-line data are transmitted to the ground experimental station via military and civilian communication links. The transport plane flew several missions and the data revealed the fact that the cosmic neutron and the cosmic electromagnetic radiation level increase as the flight altitude increases from 1,500 ft; the in-flight cosmic radiation is the lowest at the low-level flights below 1,500 ft. The helicopter follows the designated routes in contour flights, 33 feet above ground at a speed of 37 knots, covering a land area of 1.4 million square meters in a one-hour low level aerial survey. The detection limits in such low-level flights are down to 0.1 nSv/h for gamma radiation and 0.5 nSv/h for neutrons The air-borne survey has proved an efficient, prompt way to rapidly determine the radiation concentration in mid-air as well as near the ground. CZ9827816

FAST RADIOCHEMICAL EXTRACTION OF CARBON IN PHOTOACTIVATION ANALYSIS OF PURE BORON

Yu.M.Tsipenyuk ', B.A.Chapyzhnikov2 and M.Fedoroff3 ' P.Kapitza Institute for Physical Problems RAS, Moscow, Russia " V'ernadskii Institute of Geochemistry and Analytical Chemistry RAS, Moscow, Russia. ' Centre de Chimie Metalhtrgiqtie, 15, rue Georges Urbain, Vitry-sur-Seme, France.

The problem under consideration was stimulated by the investigation of a possible violation of the Pauli exclusion principle during the early stage of the Universe formation, i.e. in the period of nucleosynthesis. The experiments were carried out at the 30 MeV microtron in the IPP by the photoactivation technique and aimed at searching of chemically boron-like carbon nuclei in the samples of pure boron. Preliminary tests of different samples of pure boron for impurity content performed by the photo- and thermal neutron activation, chemical, mass- and optical spectroscopy analyses have showed that unfortunately the carbon content in the samples is rather high and is at a level (3-7) x 10'2 wt. %. Besides there are also chlorine and ( ~10'2 wt. %) in the samples and metallic impurities with a total level of about 0.1 wt. %. That is why the non-destructive activation variant of the determination of carbon nuclei content in boron is impossible and therefore we developed a special radiochemical procedure for pure boron extraction from the samples in the form of B2O3 or H3BO3. The procedure contains two stages: — alloying of the irradiated sample in a mixture KNO3 + KOH followed by decomposition of carbonates and distillation away of "CO2; — extraction of metals by sodium diethyldithiocarbonate. The alloying technique is based on a fast decomposition of the irradiated sample in the mixture of KN03 +K.OH (6:1) at the temperature of 600 °C during 5 min, dissolving of the cooled mixture in water (10 ml) and subsequent distillation off of the "CO2 from boiling acidic solution of HCI (30 ml) during 5 min The extracted carbondioxide is absorbed in 12M KOH whose P*-activity was measured by the (7-7) - coincidence spectrometer to check the efficiency of the extraction. The measurement showed that during 5 min 94% of the carbon atoms is extracted from the solution For fast extraction of metals a sodium diethyldicarbonate was used. Hydrochlororic acid was added to the solution followed by citric acid and carbonate. As a result, metallic complexes were formed and then a chloroform was added The activity of the water phase after extraction, which contains the purified boron acid, was measured with (7-7) - spectrometer The time needed for extraction of the metals is about 20 min.

-156- CZ9827817

NEUTRON ACTIVATION ANALYSIS OF AN EGYPTIAN MONAZITE ORE SAMPLE

E. A. Eissa, N. B. Rofail, L. S. Ashmawy and A. M. Hassan Reactor and Neutron Physics Department, Atomic Reactor Division, Nuclear Research Center, Atomic Energy Authority, P. O. Box 13759, Cairo, Egypt.

The absolute sensitivity of a gamma-ray line following thermal or epithermal neutron activation is expressed as the product of four terms, namely, the intrinsic, irradiation, decay and measurement factors. The total absolute sensitivity of this line is the linear sum of the absolute sensitivities due to thermal and epithermal activation. A FORTRAN computer program was prepared on the TANDY 3000 NL PCA to calculate the total absolute sensitivity of most of the intensive delayed gamma-ray lines obtainable from the thermal and epithermal neutron activation for all of the naturally occurring nuclides. Another special program was prepared for the total absolute sensitivity of a gamma-ray emitted by radioactive daughters such as Pa-233 from Th- 233 and Np-239 from U-239. For specimens of a monazite ore sample long-time irradiation (about 48 hours) was carried out at the (ET-RR-1) reactor core periphery. The monazite ore sample was separated from the associating minerals in the sand of Abou-Khashaba of Rashied (Rosetta) area in the Mediterranean sea (North of Egypt). The separated Monazite ore sample were provided by the Nuclear Material Authority of Egypt. The cadmium difference method was applied to thin gold foils for the absolute thermal and epithermal neutron flux determination . The gamma-ray spectra were measured by a HPGe detection system. The computed sensitivity tables were helpful in identifying the radioisotopes contributing to the gamma-ray spectra and in evaluating the elemental concentration of the monazite constituents. Most of the rare earth elements were observed and their concentrations are reported. La, Ce, Nd, Sm and Th were found as major elements, while U, Tb, Hf and Eu as minor elements.

-157- CZ9827818

DETERMINATION OF TOXIC ELEMENTS IN TOBACCO BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Giinseli Yaprak*, N.Fiisun Qam** * Ege University, Institute of Nuclear Science, 35100 Bornova-hmir, TURKEY **Ege University, Faculty of Science, Department of Physics, 35100 Bornova-hmir, TURKEY

The presence of toxic elements in tobacco is of special importance because the inhalation or ingestion of small amounts of them has been known to cause serious damage to human tissues. Considering the large smoking population it is therefore of interest to analyze the toxic elements in cigarette tobaccos. In this work, the concentration of toxic elements in the tobacco of six different brands of domestic and two brands of imported cigarettes heavily smoked in Turkey were determined using instrumental neutron activation analysis (INAA). Neutron activation analysis is adequate to this study since it provides information on a large number of elements simultaneously and the problems associated with the dissolution of complex matrixes and possible contamination of the sample from reagents are avoided.

-158- CZ9827819

DETERMINATION OF ARSENIC CONCENTRATION IN DRINKING WATER FROM TUBEWELL

N.I. Molla, S. Basunia, Laila Zaman, S.M. Hossain, R.U. Miah, and M. Rahman Bangladesh Atomic Energy Commission Institute of Nuclear Science and Technology Atomic energy Research Establishment P.O. Box 3787, Dhaka-1000, Bangladesh

Arsenic contamination in drinking water from tubewells in the north-western and south- western region of Bangladesh has posed a great risk to public health. Most of the affected districts are primarily reported to have arsenic concentration in drinking water more than the permissible level, set by WHO, of 0.01 mg/L. Therefore, use of a reliable analytical technique like instrumental neutron activation analysis (INAA) for bulk sample analysis, covering a wide sampling area, has become an essential task. In this work the analytical results of forty tubewell water samples from two districts, namely Chapainawabganj and Faridpur, are reported. The concentration level of arsenic are found to be 28 to 378 ng/L. The detection limit is 3 ug/L. Tubewell samples, collected from different locations of Chapainawabganj and Faridpur municipal areas, and standard reference material NIST 1643d (water) together with primary standard of arsenic (100 u.g/L) were irradiated at the TRIGA Mark-II research reactor, AERE, Savar with a nominal neutron flux ~ 1012 cm"2 s"1 for one hour using the La2y Susan facility. After irradiation, allowing a cooling time of 50-70 hours, radioactivity of the 16As radionuclide was measured with a high resolution HPGe detector in combination with a PC based S-100 MCA master board packages. The detector was previously calibrated with a set of standard y-ray sources. The y-ray spectra were analyzed using Y-software Peakgr-10 and GANAAS and manually. It has been possible to minimize the contribution of interfering 82Br and 122Sb radionuclides and the background of 24Na by optimizing irradiation time, cooling period and counting time. The quality of the analysis has been crossed-checked by analyzing the NIST SRM- 1643b with respect to the primary standard of arsenic (100 ug/L). It is concluded that that arsenic concentration level is much higher in underground water of some areas posing serious threat to public health. However, hundred and thousands of water samples are yet to be analyzed to create a data base.

-159- CZ9827820

VANADIUM IN ORGANIC FOSSILS AS DETERMINED BY NUCLEAR-PHYSICAL METHODS OF ANALYSIS

N.N. Nadirov and V.P. Solodukhin * Scientific-Industrial Center "Munay", Republic of Kazakstan; *Institute of Nuclear Physics, National Nuclear Center, Republic of Kazakstan

Kazakstan is one of the countries with the largest geological resources possessing, together with a variety of mineral raw materials, large bodies of non-traditional organic fossils: high- viscous oils (HVO), oil-bitumen rocks (OBR), oil shales (OS), coal shales (CS) and others. This fossils, playing a role of specific natural sorbents, concentrate large quantities of rare and scattered elements. Of the latter group, one of the most valuable elements is vanadium. From the scientific point of view it may provide valuable information about the origin and migration peculiarities of organic fossils. And, in practical relations, it is one of the most important migration elements which is used largely in metallurgical industry. Simultaneously vanadium may present a certain risk, because it is released to the environment on burning of oil and oil products, decreases the activity and selectivity of catalyzators in the processes of catalytical cracking, may contribute to an enlarged wear of various engines due to its presence in oil products, etc.. Therefore, it is necessary to study the content of vanadium in organic fossils and in products of their processing. The most traditional ways of determination of vanadium by chemical, physical-chemical and physical methods are based on the preliminary decomposition of samples. This essentially complicates analysis and may lead to additional errors. Besides, most of these methods have unsatisfactory detection limits, usually > 1 ppm. This does not exclude a possibility of their use for routine analyses, but for many purposes it is necessary to have methods without sample decomposition and possessing a lower detection limit, < 0.1 ppm. Such requirements, may be largely fulfilled by applying nuclear-physical methods of analysis (NPMA). In this paper, results are presented of several year investigation to study possibilities of the NPMA for the determination of vanadium in organic fossils and applications of these methods to scientific and practical tasks. For these purposes, various versions of activation analysis (AA), X-ray fluorescence analysis (XRFA), electron resonance (ESR) spectroscopy and atomic emission with inductively coupled plasma spectroscopy (AES-ICP). Advantages and pitfalls of individual methods are discussed. The techniques developed can be used for estimation and calculation of stocks of vanadium in organic fossils at the territories of Kazakstan, Tatarstan and along the Volga-river. Analysis results helped in discovering new, industrially important deposits of this valuable metal. Quantitative determination of vanadium was carried out at different stages of technological processes of its extraction from HVO and OBR. Results of analyses allowed to reveal the most effective versions of technologies of demetallization of these fossils. Content of vanadium was also studied in different locations of HVO-deposits being explored by the method of inside-stratum burning. Results of analyses showed that the concentration of vanadium in oil decreases considerably with increasing temperature, that is, a considerable part of vanadium (up to 60 percent) may be lost irretrievably. Thus, for the exploration of these deposits a method of vapor-thermal influence onto the stratum was recommended, by using of which the loss of vanadium is insignificant. The analytical results obtained, as well as the recommendations drawn at their basis, are used for scientific and practical purposes in order to solve the problem of the complex exploration and processing of natural resources.

-160- CZ9827821

S. Rastikerdar Physics Department. Isfahan University, Isfahan, Iran

rays as well as X-rays and the other suitable for measuring, the ga hale been used. The resolution of the detectors we,e mea u d and ov ^ ^ for »Co gamma rays. During the »»«7^'^JS Jo^Se the whole system safe and also these chambers the background was reduced dram". To ma ^ ^ coupled to for saving time in activation analysis a fully ^^ ^™|S system for activation analysis the system. Our main purpose ,s to ^^^^^Jnuim. ^though our tests KS'Bff.SS S S-" ^ , ve, promising. ta this paper we w,l, discuss about the details and the future prospects.

PAQEiS) I left BIAMK _1UI wmrarowOTiBMMWiiwiiwiwwai Topic 3

ACTIVATION ANALYSIS AND OTHER RADIOANALYTICAL METHODS

Poster presentations

-163- P3-1

226Ra DETERMINATION IN PHOSPHOGYPSUM BY ALPHA-PARTICLE SPECTROMETRY

J. L. Aguado1*, J. P. Bolivar1' and R. Garcia-Tenorio2) 1) Departamento de Fisica Aplicada, EPSLa Rabida, Universidad de Huelva, CtraPalos-La Rdbida s/n, 21819-Huelva, Spain. 2) Facultadde Fisica, Universidad de Sevilla, Apdo 1065, 41080-Sevilla, Spain.

Phosphogypsum is the main by-product of producing phosphoric acid by reacting phosphate rock with sulphuric acid. In the South-West of Spain and near to the town of Huelva there is a big industrial complex with some factories devoted to the production of phosphoric acid, which produces 3 • 106 metric tons of phosphogypsum per year. Around 80% of this amount is stored in a nearby salt-marsh area, in big piles named "gyp-stacks". These wastes contain high concentrations of 726Rz (about 50 times higher than in typical soils). Due to the radiotoxicity of this radionuclide, its decay to 222Rn which can emanate in high amounts from the piles, and the significant contribution of its daughters to the gamma exposure rate, the study of 22

-164- P3-2

ELEMENTAL ANALYSIS OF SELECTED SOIL AND FERTILIZER SAMPLES FROM EASTERN SAUDI ARABIA

A. Aksoy, F. Z. Khiari and N. Al-Shayea Energy Research Laboratory, Research Institute, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

One of the best nondestructive bulk analysis methods is Neutron Activation Analysis (NAA). The wide use of this technique in various areas in the last 30 years proves that the technique is very well suited for elemental analysis [1]. Due to the importance of soils and fertilizers in agriculture, studies of element concentrations in the soil and fertilizer samples are important for a better understanding of the effect of each element on the end products [2-3]. Local soil and fertilizer samples were studied for elemental analysis using slow neutron activation analysis. A slow neutron flux of about 106 n/cm2-sec was available which was obtained by slowing down 2.5 MeV neutrons from the D(d,n)3He reaction at the KFUPM 350 keV Ion Accelerator. The induced y-ray activities were measured by a HP-GMX detector and a PC based data acquisition and analysis system [4-5], Calibration curves were established for the elements present in the samples by activating certified standards of similar matrix from NIST, USA and IAEA, Austria From the calibration curves, the absolute concentrations of the elements K, Mn, V, Al, Na, Cl, Ba, Sr and Mg were determined. The concentrations of these elements in the soil and fertilizer samples varied from ppm to wt.%. In this paper, the study of selected local seven soil and six fertilizer samples from Eastern Saudi Arabia using the NAA technique will be described and the results of the absolute concentrations of the elements K, Mn, V, Al, Na, Cl, Ba, Sr and Mg in soil samples and K, Mn, V, Al, Na and Cl in fertilizers will be presented. The results will be discussed in terms of mineralogy as well as comparison among the samples.

References: [1] J Csikai, Intl. Conference in Nuclear Data in Science and Technology, 13-17 May (1991), Julich, Germany [2] A.R. Mermut, J.C. Jain, Li Song, R. Kernch, L. Kozak and S. Jana, J. Environ. Dual 25 (1996) 845-853 [3] B. Marschner, K. Stahr, and M. Renger, J. Environ. Dual. 21 (1992) 410-419 [4] A. Aksoy, A.A. Naqvi, F.Z. Khiari, F. Abujarad, M. Al-Ohali and M. Sumani, Nucl. lnstr. andMeth. A 353 (1994) 558-561. [5] F.Z Khiari, A Aksoy and M. Al Haddad, 14th Intl. Conf on the use of Accelerators in Research and Industry, Denton, Texas, U.S.A., (1996)

-165- P3-3

NEUTRON INDUCED GAMMA-RAY SPECTROSCOPIC AND X-RAY FLUORESCENCE INVESTIGATIONS OF BRITHOLITE VEINS OF BASOREN VILLAGE (TURKEY)

Tanil Akyilz*, £etin Bolcal**, Rahmi KU?er, Pelin Saritepe and Sevim Akyiiz* * Cekmece Nuclear Research and Training Center, P.K. I Havalimani, Istanbul, Turkey ** Faculty of Arts and Sciences, Kitltur University, Istanbul, Turkey 'Department of Physics, Istanbul University, Vezneciler, 34459, Istanbul, Turkey

High resolution y-ray spectroscopic investigations of neutron induced mineral samples obtained from the deposits of the Basoren area which is located about 670 km Southeast of Ankara (Turkey), within the Northeast margin of the Eastern Tauride belt, are reported. The geological investigation indicated that the mineral sample is mainly Bntholite, {(REE,Ca,Na)s • [(Si,P)O4]3 • (OH,F)}. The Y-ray spectrum of the natural sample shows all the elements of the Th decay series and a few elements of the U decay series The sample irradiated by 14.6 MeV neutrons shows some rare earth elements and Sc, Cr, Mn, Kr, Sr, Y, Ba and Zr peaks in addition to those of U and Th decay series The natural activities of the mineral sample for a and 3 radiations are found to be Ac,= 1 72 MBq/kg and Ap= 0.40 MBq/kg, respectively, which are consistent with y-ray spectroscopic results of the Th decay series. The quantitative XRF analysis indicates that the sample contains Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, P, La, Ce, Nd, Y, Th, Sm, Gd, Eu in different amounts.

-166- P3-4

RADIOISOTOPE X-RAY FLUORESCENCE AND NEUTRON ACTIVATION ANALYSES OF THE TRACE ELEMENT CONCENTRATIONS OF THE RAINBOW TROUT

Tanil Akyiiz*, Qetin Bolcal**, Rahmi Kii?er-, Erdal §ener , Asiye Bassari*, Mustafa Yildiz , Zarife Kaplan', Giilten Dogan and Sevim Akyfiz * Cekmece Nuclear Research and Training Center, P.K I, Havalimani, Istanbul, Turkey * * Faculty of Arts and Sciences, Kiiltur University, Istanbul, Turkey • Department of Physics, Istanbul University, Vezneciler 34459, Istanbul, Turkey - + Faculty of Aquatic Products, Istanbul University, Vezneciler, Istanbul, Turkey

Every living organism from the simplest one to the more complex contains small amounts of metals. The fundamental importance of metal ions in biological processes has become clearer in the last decade. The effects of heavy metal pollution of the environment and the living organisms have started exhaustive studies on the medical aspects of the toxic elements. On the other hand it is known that all marine and aquatic organisms can accumulate trace and toxic elements to different degrees depending on their physiological mechanisms and the environmental pollution The trace element concentration of the fish is very important since it is directly related to the human health. The subject of this paper was the determination of the trace element concentration in agricultural rainbow trout samples farmed in Sapanca, Aquaculture Facility of Aquatic Products Faculty, The University of Istanbul, in order to investigate the effects of environmental pollution to the ecosystem. The muscles and livers of the ten rainbow trouts (Oncorhynchus mykiss; N, I ~52) obtained from Sapanca, Aquaculture Facility of Aquatic Products Faculty, The University of Istanbul (Turkey), have been analysed quantitatively for some minor elements using radioisotope energy dispersive X-ray fluorescence (EDXRF) and neutron activation analysis methods. It is found that samples contain Ca, Na, K, Sc, Cs, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Ba, Br, La and Ce in different amounts Comparison of the results with those of reference fish samples indicated that the agricultural rainbow trout samples have lower amounts of the elements of toxicological concern.

-167- P3-5

GAMMA ISOTOPIC ANALYSIS OF THE COALS AND ASHES FROM COAL FIRED POWER PLANTS OF TURKEY

Tanil Akyiiz, Ahmet Varinlioglu and Abdullah Kose Qekmece Nuclear Research and Training Center, P.K. I, 34831, Havalimani, Istanbul-Turkey

We have investigated the ashes produced by combustion of lignite in power stations of Turkey together with the parent coal samples with the aim of estimation of potential adverse impact on human health. Gamma-isotopic analysis technique was used to determine radium, uranium, thorium, potassium and caesium contents in coal and fly ash samples originated from the soutwestern and middle part of Anatolia. Gamma-isotopic analysis indicated that all samples contained Ra-226 (coal samples: 89-148 Bq/kg; ash sample: 15-122 Bq/kg), U-238 (coal samples: 2.1-3.9 ppm; ash samples: 8.9-140 ppm), Th-232 (coal samples: 1.8-10 ppm; ash samples: 7.4-38 ppm), and K-40 (coal samples: 26-67 Bq/kg; ash samples: not detected). The contents of Cs-134 and Cs-137 have been in the samples below detection limits

-168- P3-6

ANALYSIS OF MULTICOMPONENT SYSTEMS BY FAST NEUTRON ACTIVATION

A.V. Andreev Slate Institute for Rare Metals, National Scientific Center "GIREDMET" Bol.Tolmachevskyper.5, Moscow, 109017, Russia

The author presents the data on developing accurate techniques for determining components of multicomponent systems using fast neutrons of a neutron generator. 14.5- and 2.5-MeV neutrons with a flux density of 5xlO10 and 7xlO8 n cm'2 s'1, respectively, were used. The induced sample activity was measured by a gamma-spectrometer with a HPGe detector having an efficiency of 45% and an energy resolution of 2.1 keV. Systematic and random errors are exhaustively studied; methods and devices are developed for diminishing the total error to 0.5-2.0 rel.% for macro-component determination (above 0.1 mass.%). Based on the above investigations, accurate techniques are developed for determining various macro-concentrations of the following elements: B, N, O, F, Na, Al, Si, P, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Ga, Se, Br, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Sn, Te, I, Ba, La, Ce, Nd, W, Re, Ir, Pt, As, Au, Ti, Pb. Nuclear reactions and measured isotopes used for determining the above elements are listed, as well as examples of results of the analysis of various objects.

-169- P3-7 DETERMINATION OF IODINE IN DRINKING WATER Ezidin A. Arafa*\ Fathi H. Beshewa+ and AH I. Saleh*+ *Department of Chemistry, University of AI-Fateh, P.O. Box 13203, Tripoli (Libya). *TajotiraResearch Centre, P.O. Box 30H~S, Tajoura (Libya)

A recent medical investigation of the thyroid gland indicates the evidence of goiter in some area of Libya. To investigate this problem further, there is a need to determine the concentration levels of iodine in drinking water. In this study, drinking water samples have been analysed for iodine levels using radiochemical neutron activation analysis technique. The developed method is simple, fast and accurate. 2.5 ml of drinking water is pipetted into a polyethylene capsule and 50 ul of concentrated NH4OH is added The capsule is then sealed, cooled in liq Ni and irradiated in a thermal neutron flux of 5 x 1012 n.cm"2.sec"' for five minutes. After irradiation the capsule is opened and its content is transferred into a separatory funnel containing 3 ml of deionised water. The mixture is acidified with 20 u.1 concentrated HC1 followed by the addition of 5 ml of iodine solution in CCU and shaken vigorously for at least one minute. The organic phase is transferred into a polyethylene test tube As a standard, solution of iodine, prepared from NHJ and irradiated in the same way, is used. Samples and standards were counted for 10 minutes on a HP(Ge) detector and the peak area at 442.7 keV y-ray from !28I was integrated. The concentrations of iodine in the samples were calculated by comparison of the gamma peak areas between the samples and the standard Samples of water were collected from 28 major wells connected to the drinking water network of different regions of Libya. Our results showed that the concentration levels of iodine in drinking water have considerable regional differences. The developed analytical method and possible links of iodine contents in drinking water with endemic goiter will be discussed

-170- P3-8

METHODOLOGICAL PROBLEMS OF ACTIVATION ANALYSIS WITH RADIONUCLIDE NEUTRON SOURCES

S.A. Bakiev Institute of Nuclear Physics, Tashkent, Uzbekistan

The peculiarities of activation analysis with radionuclide neutron sources are associated with large weight samples and group irradiation of them. This may lead to a number of specific effects. Analysis of the possible changes of parameters of the activation equation allowed to reveal a number of factors that may cause errors. In the performed investigations the influence of these factors on accuracy of analysis has been estimated and the methods and techniques for correct consideration of them have been elaborated. 1. The problem of calibration of irradiation positions in the multielement analysis with group irradiation of samples has been investigated and solved. It has been shown that the differences in position coefficients may reach up to 20% for different nuclides. The relations of these coefficients with nuclide activation parameters and spectral characteristics of then neutron field have been found and a method of position coefficients determination has been developed. 2. It has been shown that the influence of the possible deviation of resonance neutron spectrum from the 1/E law is unimportant for the analysis results. 3. Comparative analysis of shielding coefficients for different types of ores and neutron flux depression coefficients showed that correctness of standardisation by using standard samples, having the matrix different from the studied one, and the possibility and conditions of applicability for different types of ores of the same position coefficients as well. 4. The conditions of isotropness of neutron albedo (and activation of samples) for different moderators have been found. 5. The effects of self-shielding of neutrons in gold-containing samples have been studied in detail. For the case of even distribution of gold in the sample the limits of the effects have been obtained in the whole range of concentrations at the irradiation by both thermal and full spectrum neutrons. The method of correct determination of neutron self-shielding coefficients for real gold containing samples, that eliminates defects of the formerly elaborated method and eliminates substantial systematic errors, has been developed. It has been shown that the differentiation of self-shielding coefficients under the group irradiation of samples is observed, which should be taken into account. Investigations carried out are the base for working out of the complex methods of element analysis, which is now being implemented in practice.

-171- P3-9

NUCLIDE COMPOSITION AND BURN-UP CHANGE OF WER-1000 AND WER-440 PWRs SPENT FUEL ALONG FUEL ELEMENT RADIUS

V.I.Borisenkov, A.P.Chetverikov, G.A.Timofeev State Scientific Center Research Institute of Atomic Reactors, Dimitrovgrad, Russia

At present, VVER-1000 and VVER-440 are the basic types of power reactors in Russia. Therefore, much attention is paid to the investigation of fuel of the above mentioned reactors, especially to the elucidation of changes of nuclide composition as a function of burn-up. Experimental data concerning the radial distribution of plutonium and transplutonium elements are practically absent in the literature In this paper, analysis results of fifteen microsamptes of the spent fuel taken by an ultrasonic method are presented. The fuel burn-up was estimated by measurement of the accumulation of fission products by isotope dilution mass spectrometry using isotopes of -145 + neodymium-146 as burn- up monitors The results obtained have shown that the distribution of plutonium along the fuel element radius has an irregular nature

-172- P3-10

URANIUM-233 AS AN ALTERNATIVE TO THE URANIUM-PLUTONIUM SPIKE IN DETERMINING OF THESE ELEMENTS IN NUCLEAR FUEL BY ISOTOPE DILUTION MASS SPECTROMETRY

V.I.Borisenkov, Yu.S.Popov, G.A.Timofeev, A.P.Chetverikov State Scientific Center, Research Institute of Atomic Reactors, Dimitrovgrad, Russia

At present,- isotope dilution mass spectrometry remains one of the most accurate method for the determination of uranium and plutonium in nuclear fuel. Particular attention should be given to the preparation of complex spikes containing enriched isotopes of uranium and plutonium, because an error of the element determination is given to a considerable extent by the accuracy of the spike preparation. Furthermore, it is necessary to en- sure the conversion of plutonium in fuel and spike solutions to the same chemical state, and in particular to the same valency before separation This requires carrying out of redox reactions and may be a source of additional errors. In the present paper, the authors examine a method for the determination of uranium and plutonium content in which only one isotope - uranium-233 is used as a spike and mass- spectrometry and alpha-spectrometry are used as measurement methods. The procedure is easy in implementation and ensures the determination of plutonium with an error of 1.2%. This value is comparable to that of isotope dilution mass spectrometry analysis (0.6-1.2%) with the application of complex spikes.

-173- P3-12

DETEFF- A MONTE CARLO CODE FOR EFFICIENCY CALCULATIONS IN GAMMA - SPECTROMETRIC MEASUREMENTS Nestor Cornejo Diaz, Danyl Perez Sanchez Center for Radiation Protection and Hygiene, Havana. Cuba

For gamma spectrometric measurements it is necesary to know the source-detector system efficiency. Frequently, reference sources with the desired matrixes and geometries don't exist and the efficiency of the system has to be evaluated by means of numeric methods. The presented work show the description of the Monte-Carlo program DETEFF, that calculates the efficiency of cylindrical Nal, Csl, Ge or Si detectors for photons energy until 2 MeV and several sample geometries. These sources could be punctual, plane, cylindrical or rectangular. The energy spectrum appears on the screen simultaneously with the statistical simulation. The program was validated for the analysis of environmental samples during the international intercomparison exercises. The calculated and experimentally estimated efficiencies coincide well in the standard deviations intervals.

-174- P3-13

THE GOLD ANALYSIS IN SEDIMENTS BY ACTIVATION WITH NEUTRONS ISOTOPIC SOURCES AND X-RAY FLUORESCENCE

L. Daraban, C. Cosma, J. Bacso*, Laura Daraban Faculty of Physics, University"Babes-Bolyai" 3400 Cluj-Napoca, Romania *A TOMKI.H-4001 Debrecen,P.O.Box.51, Hungary

By using neutron activation analysis with the help of the 197Au (n,Y )198Au nuclear reaction, we analysed the native gold from the river sands and from sedimentary or hydrothermal quartzypherous rocks, studying its concentration and its appearance forms. For irradiation were used two isotopic neutron sources (type 241Am-9Be and 239Pu-9Be ) which have a constant fluence of 6.6 «107 n/s. The sources were introduced in a paraffin block with the purpose of neutron thermalization. Systematic studies have been made for removing the analysis errors produced by neutron self-shielding and by geometrical factor in the samples containing gold. The samples irradiated during 4-6 days were measured after a cooling time, calculated for removing the interference with the 116mIn radionuclide. The gamma-ray spectra emitted by the irradiated samples were measured with the help of a high-resolution type Ge (Li) detector coupled to a multichannel analyser type ICA-80. The gold concentration was determined by measuring the 412 keV gamma-rays of the 198Au radionuclide, using standard samples. The detection limit was established at 27 ppm Au for this installation, what means that preferably preconcentrated samples are used instead of native samples with a lower content of gold. Another approach used was X-ray fluorescence analysis, using two installations which work differently. It was noticed that the analyser which uses the diffraction on the LiF crystal, for X-ray fluorescence spectrum analysis, emitted by the sample, has a reduced sensitivity for the gold determination (only 0.01%), but it has good resolution. On the other hand, the X-ray fluorescence analyser which uses a Si(Li) detector, is extremely sensitive, reaching ppm concentrations for the gold determination, although it has a weaker resolution. With the help of the latter, system were determined 25 elements in a series of golden sands and sedimentary rocks samples. It was noticed that in the preconcentrated golden samples, the gold level can reach hundred of ppm and it is accompanied by high levels of Zr and Ti. In conclusion, by using the studied radioanalytical methods for analysis, were investigated the golden zones from the so-called "The Golden Quarter" from the Western Carpthians mountains from Romania, localising the rivers containing golden alluvia.

-175- P3-14

APPLICATION OF INAA IN DETERMINATION OF TRACE ELEMENTS IN URINARY CALCULI

F.A. El-Amri, RE. Damja Dept. of Chemistry, Al-Fateh University P.O.Box 13361, Tripoli, Libya

M.A.W. El-Gabroun, A.S. Musbahi, S.S. Ghiblawi, B.M. Abuhaggar and M.K. Jefayri Urology Dept., Al-Khadra University Hospital P.O.Box 7420, Tripoli, Libya

The concentration of Co, Fe, Se, and Zn in 53 urinary calculi of Libyan patients were determined by instrumental neutron activation analysis (INAA) and were found to be in the ppm range and to differ in concentration. A pattern of the concentration of trace elements in these stones was analysed regarding the age, sex, residency, position of the stones in the urinary tract and the presence of preoperative infection.

-176- P3-15

A NEW METHOD OF RADIOSTRONTIUM CONTENT DETERMINATION USING SYNTHETIC SELECTIVE SORBENTS

A.I.Ermakov, I.A.Kashirin, A.V.Kovalev, V.B.Ribalka, A.I.Sobolev, V.A.Tikhomirov MosSIA "Radon ", Moscow

The present methodology is based on using synthetic selective sorbents containing functional groups of various "crown" ethers. These sorbents combine high selectivity and capacity of these ethers (50-60mg Sr/g dry sorbent) with good dynamic qualities of the synthetic fibres (filtration speed up to 3ml/cm2 min). Similarly to ionites these fibres can be regenerated and used many times (not less than 400 cycles). Description of the procedure. Strontium is effectively sorbed with fibres from the leaching solutions produced from different kinds of samples (nitric acid 5.5 mol/L to 7.5 mol/L). Then the fibres are washed with 6.5 mol/L nitric acid. When 20 free column volumes of the acid are used, the greater part of macro- and microcomponents are separated ( 97-99 % Ca, Mg , Fe, as well as artificial and natural radionuclides including Ra). The strontium sorbed is practically completely eluted in 10-12 free column volumes of ammonia solution containing disodium EDTA. Additional purification of strontium is provided as a results of its selective precipitation as sulphate in an EDTA solution having pH 5.0 to 5.2 ; Ca, Mg, Pb, rare-earth elements and other elements remain in the solution in this case. If the necessity arises, additional purification from Ba and Ra can be achieved by the preliminary precipitation of their sulphates at pH 7.3 to 7,5. The total strontium yield for all stages of analysis amounts to 50-60 % . Radiochemically pure strontium sulphate is deposited on the planchet and represents a source for radiometric counting. The methodology has been tested while analyzing different types of real samples of soil, water, milk, potatoes, herbs, etc. The methodology is simple to use and it does not require a high qualification level of the personnel. It can easily adapted for such instruments as liquid scintillation counters (with strontium-85 gamma-tracer) as well as low-background gas-flow counters (with stable strontium carrier).

-177- P3-16

LOW-LEVEL RADIOACTIVE MEASUREMENTS OF RADIOCHEMICAL ISOLATED NUCLIDES FROM SAMPLES OF CONTAMINATED AREAS AND MATERIALS

B. Gleisberg*, S. Niese, M. Kohler Nuclear Engineering arid Analytics, Rossendorf, Inc. P. O. Box 510119, D-01314 Dresden, Germany

The investigation of radioactive contamination in the surroundings of NPP (nuclear power plants) and uranium mines demands the determination of radionuclides at extremely low activitiy levels, especially for the forecast of transportation by the different pathways and for the estimation of the efficiency of natural and artifical barriers for the storage of radioactive wastes. The measurements of some nuclides by a-, p- and y-spectrometry are carried out in an underground laboratory (47 m thick rock cover). The p- and y-detectors are individually shielded by 10 - 17 cm lead and are arranged in a metallic shielded counting chamber. The extremely low background enables measurements in the mBq level for chemically isolated fractions. Some applications of the developed radiochemical and instrumental methods are described: i) Natural isotopes of Pb, Ra, Ac, Th and U in pit water and other sources can be isolated from the matrix and interfering nuclides by group separation methods and individual separations. Isotopes of Ra and Pb are precipitated with barium sulfate and measured by y-spectrometry. An additional determination of 226Ra is possible by emanometry of the dissolved sulfates. Nuclides of Th and U are determined by a-spectrometry after isolation by anion exchange and extraction steps. 227Ac is analyzed by a-spectrometry of its doughter 227Th after growing and repeated separation from 227Ac. ii) Artificial actinides and rare earth elements in water of the primary circuit of a NPP and in waters of nuclear fuel element storage basin are analyzed by a- and y-spectrometry of the separated fractions. The isolation of Pu-nuclides from 3-valent actinides, the matrix (boric acid) and interfering nuclides is realized by phosphate precipitation, extraction and a cation exchange procedure. The group of REE and 3-valent actinides are electrodeposited together. The results obtained by a- and y-spectrometry are identical. The chemical yield is controlled by addition of ug-amounts of a La-carrier and measurement by ICP-MS. iii) For selected nuclides a further background reduction is reached by using P-y-coincidence techniques with a HPGe-detector as the y-spectrometry system and a thin plastic scintillator as the p -sensitive detector. Radiochemical procedures are applied for the determination of iv) nuclides from the uranium-, thorium- and actinium- decay series in incorporation samples, plant materials, air samples and soils. v) artificial actinides and Sr-90 in incorporation samples, plant materials and air filters.

-178- P3-I7

THE ANALYSIS OF a-NUCLIDES IN HLLW IN THE TRPO PROCESS

Tian Guoxin, Liang Junfu, Song Chongli, Jiao Rongzhou Institute of Nuclear Energy Technology, Tsinghua University, Beijing 102201

The hot test of the trialkyl (C6-Cs) phosphine oxide (TRPO) process for the removal of transuranium (TRU) elements from a genuine high level liquid waste (HLLW) in China has been carried out in the Institute of Nuclear Energy Technology, Tsinghua University, Beijing. This paper presents the results and the analytical methods for the determinatyion of TRU elements in the hot test. The total activity of a-nuclides was determined using a Au-Si surface barrier detector. The activities of M7Np, ^'Pu, 241Am were determined after Np, Pu, Am were separated from the HLLW with P204. The experimental results show that more than 98% of Pu is present as Pu4+ species and more than 70% of Np as Np4* species in the genuine HLLW. In the experiment, some Np(V species was converted to Np4+ species and extracted into the organic phase nearly completely, thus the decontamination factor of Np was higher than was expected. Plutonium was extracted completely after 3 stages of centrifugal extractor, from the fourth extractor to the twelfth extractor the content of plutonium in the aqueous phase was not changed, which means that a little amount of plutonium (about 5%) in the genuine HLLW existed as polymerized or hydrolyzed species which could not be extracted by TRPO. The distribution ratios of americium increased with the extraction times due to the decrease of the extractable elements, such as RE and Fe3+. After 12 stages of centrifugal extractor, the activities of ^'Np, "'Pu, ^'Am were 20, 34, 135Bq/mL respectively, and the HLLW became LLLW of a radiation.

-179- P3-18

STUDY OF REACTOR PRESSURE VESSEL STEEL SPECIMENS USING GAMMA AND MOSSBAUER SPECTROSCOPY

R. Hinca, P. Uvitfik, V. Slugeii, J. Lipka, J. Ha&ik, I. T6th, R. Grfine, J. Degmova Department of Nuclear Physics and Technology, Slovak University of Technology, Ilkovidova 3, 81219 Bratislava, Slovakia

The reactor pressure vessel (RPV) is the most important component of a nuclear power plant (NPP) and its condition significantly affects the NPP's lifetime and operational characteristics. One of the basic requirements in nuclear reactor technique is ensuring the sufficient safety margin and reliability of the materials used concerning their operational mechanical, thermal or radiation treatment. In our study the gamma spectroscopic analyses and first experimental results of original irradiated RPV-surveillance specimens are presented and discussed. In 1994, the new "Extended Surveillance Specimen Program for Nuclear Reactor Material Study" was started in collaboration with NPP V-2 Bohunice (Slovakia). The first batch of the specially prepared specimens for M6ssbauer spectroscopy, treated 1 year into operated nuclear reactor (equivalent to 5 years of loading RPV-steel) was measured and interpreted using the new four components approach with the aim to observe microstructural changes due to thermal and neutron treatment resulting from operating conditions in NPP The irradiation level of the used RPV-steel specimens reached the following maximal values:

Energy of neutrons Neutron flux [trfV] Neutron fluence [m'2] > 0.1 MeV 5.1 x 1016 1.2 x 1024 > 0.5 MeV 2.8 xlO16 6 7X1023 > 1.0 MeV 1.5xlO16 3.6 x 1023

The most significant change of Mossbauer spectra is observable in areas under first two components. The deterioration mechanism of RPV-steel specimens owing to fast neutron bombardment is shown in the decrease of the ratio of pure oc-iron component presence. The significant percentual decrease of about 9.9%, 7.4%, 7.9%, 4.5%, 5.3% and 5.8% is observed in all of the 6 specimens. As was expected, the value of Mossbauer effect is lower of about 4% in the case of irradiated specimens. The total specific activity of the first batch of specimens (sample k716 BM-I with the weight of 25.6 mg) was 3.2 xlO7Bq/g). It is caused mostly due to presence of''"Co and 54Mn as was confirmed by gamma spectroscopy measurements. The results obtained from the present measurements indicate that MS is an effective technique for the evaluation of microstructural changes in RPV-steels and, in combination with other spectroscopic methods (Positron Annihilation Techniques, Transmission Electron Microscopy, ...) can contribute to an increase of the NPPs operational safety. Interpretations of the results obtained from the angular correlation PAS technique are in agreement with the findings from the Mossbauer effect experiments. It will be very interesting to study the second batch of the specimens, which was taken out of the reactor after 2 years of operation in July this year.

-180- P3-19

APPLICATION OF X-RAY FLUORESCENCE ANALYSIS IN PAINT VERIFICATION

Vaclav Jiranek, Jaroslav Janda IMMUNOTECH a.s., Radiova I, 102 27 Prague 10, Czech Republic

X-Ray fluorescence analysis (XRF) with radionuclide excitation is a powerful tool for non- invasive investigation of oil or water-colour paintings and frescoes. The principle of paints or frescoes dating and verification is based on the pigment analysis from the point of view of the pigment type identification. It is well known that a particular type of pigment was used from a certain year or in a certain period. For example, the zinc white was used since 1840, chromine yellow was very favourable in the second part of the last century, etc. The number of pigments used, for example, in the 15'h or 16lh century was limited (e.g. of whites only lead white was used) and the age of such a painting is very simple to verify. The second possibility of more precise paint dating of a particular painter is based on the knowledge that there are some periods in his life in which he preferred some type of pigments towards the others. It is obvious that this way needs a large knowledge of the painter's working life and also a bulk of analyses of his paintings from different periods of his life. The main advantages of this method are : • XRF is a non-invasive method, the analysed sample is not affected, consumed or changed and it is possible to use it for other analysis; • the analysis is very fast, the results of one painting spot analysis are known within a few minutes; • the measuring equipment is mobile, it is possible to analyze unmovable objects (frescoes), very valuable paintings etc.; • XRF is a very cheap technique; while the disadvantages are: • it is only possible to decide that a painting was painted after a certain year (from the year of the latest pigment used); • the whole layer of painting is analyzed without the knowledge of the composition of separate coats; • it is impossible to find the natural or artificial pigment origin, there is no information on crystal structure. For XRF a 1 MBq 241Am annular source with Be window is used for excitation, the source gamma radiation is collimated through a cone with a 5 mm diameter hole (the spot analyzed has a diameter of approx 6-7 mm if the aperture is not used), the excited radiation is detected by a Si(Li) semiconductor detector connected with a multichannel analyzer. The presence of As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, I, Mn, Mo, Ni, Pb, Se, Sn Sr, Ti, Zn and possibly Bi, U, W and Zr is observed. The typical procedure is as follows: • element analysis of a spot of the painting where only organic pigments are supposed to be present (e.g. spot analysis of black colour where the presence of only C or C-H is supposed) to find a composition of the painting background - usually Ca, Pb, Ba, Zn white pigments; • element analysis of spots of individual colours; • identification of the pigments used, searching for their earliest application and the decision if this corresponds to the painter practise in the supposed period of his life.

-181- P3-20

INSTRUMENTAL NEUTRON ACTIVATION DETERMINATION OF IMPURITIES IN TECHNICAL COBALT AND NICKEL

M. Kadirova, N.M.Mukhamedshina, N. Jumaev, M.M. Usmanova Institute of Nuclear Physics, Uzbek Academy of Sciences 702132, Tashkent, Uzbekistan

Since technical cobalt and nickel are in wide use in producing a variety of alloys, in particular on the basis of refractory materials ( Ti, Mo, W, etc.), the preliminary determination of expected impurities in these materials is necessary. Multielement INAA techniques have been developed for the determination of 13 and 16 impurities with a limit of detection from 100 ng/g upto 100,000 and 10,000 ng/g, in technical cobalt and nickel, respectively, by using thermal neutrons and the Cd-channel of a nuclear reactor. Contents of Na, Al, Cl, K, Ca, V, Cr, Mn, Ni, Cu, As, Mo, W in cobalt and Na, Al, K, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Ag, Cd, Sn, Sb, W in nickel were determined, because complex conditions of irradiation in thermal flux, optimal time parameters, and mass of samples have been chosen. For the determination of Ni in Co the samples have been irradiated in the Cd-channel for 1 min. Spectrum was measured after 3-4 days. Because 59Co has a large capture cross-section for neutrons, the effects of the self-shielding and disturbance of neutron flux, the self-absorption of gamma-rays in the sample were taken into account by using some references and based on results that have been obtained in preliminary experiments. Samples and standards have been placed in such a way that the neutron flux disturbance amounted to less than 2-3%. A filter consisting of Al-Pb-Cd-Cu was used for absorption of low-energy y-rays of 60lnCo and 60Co.

-182- РЗ-21

COMPLEX RADIOCHEMICAL TECHNIQUE FOR THE DETERMINATION OF Pu, Am AND Sr-90 IN SOIL SAMPLES OF THE SNTS.

I.V. Kazachevskiy, G.N. Chumikov, S.N. Lukashenko, N.M. Berdinova, L.A. Ryazanova, V.M. Muratova, L.N. Smirin, V.P. Solodukhin and G.I.Sychikov Institute of Nuclear Physics, National Nuclear Centre, Republic ofKazakstan

Research on the distribution of radionuclides in various fractions of soil of the former Semipalatinsk Nuclear Test Site (SNTS) has resulted in the necessity to determine all retained artificial radionuclides - products of nuclear tests in separate soil fractions. These samples have frequently masses of a few grammes and their additional division can result in large errors and loss of information. Therefore, we have developed a technique based on Chromatographie extraction of Pu on a column with trioctilamine (TOA), while Am and Sr pass into effluent. The separation of Am, Sr-90 and Y-90 can be carried out on a column with bi-2-ethylhexyl phosphoric acid (B2EHPA). The analysis scheme is as follows. The sample calcinated at 400°C is decomposed in a mixture of HF+HNO3 with an addition of H3BO3 to prevent formation of insoluble fluorides. To the 4 resulting solution KNO2 is added to convert plutonium into Pu * and extraction of Pu is carried out using a column with TOA. The effluent is used for separation of Y (Sr-90) and Am. Pu from the column is washed off by benzene and is re-extracted by a solution of H2SO3. The preparation of a spectrometric source consists in evaporation, dissolution of the residue in IM HNO3, and coprecipitation of Pu with NdF3 in the presence of 5M HF. Y and Am are extracted from the effluent using the following scheme. Precipitation with CaF^ is carried out 2 times, then pH of the solution is adjusted to 1.8-2.0, and Y and Am are extracted on the column with B2EHPA. Am is eluted by 0.5M HNO3, and Y by 3M HNO3. The preparation of a spectrometric source of Am is similar to that of Pu, but for Y precipitation is used of YF3 with a rather large (500 |ig) amount of carrier of stable Y. The determination of the contents of Pu and Am in investigated samples is carried out by alpha-spectrometry, and the determination ofthat of Sr-90 (Y-90) is carried out by beta-spectrometry. The chemical yield is determined using tracers of Pu-236, Am-243 and Y-88, which are introduced at the initial stage of analysis. The yield of Y-88 is determined by gamma- spectrometric measurement. Investigation of metrological characteristics of the technique carried out with both artificial mixtures and real samples has shown good reproducibility, sensitivity and selectivity of the technique, which is used for the characterization of contamination of the SNTS.

-183- РЗ-22

PROMPT- GAMMA NEUTRON ACTIVATION ANALYSIS OF BULK SAMPLES

R. Khelifi, Z. Idiri, A. Tchantchane, and M. Seghir Centre de Développement des Techniques Nucléaires, 2 Bd. Franiz Fanon В.Р. 1017, Alger Gare, Algeria

A 5 Ci Am-Be radioisotope source which provides 1.1 x 107 n/s has been used in conjunction with coaxial HPGe detector for doing bulk elemental analysis by neutron capture in sample. Such technique has been successfully tested for determining the Ca/Si ratio in concrete samples. A comparison made between this method and a chemical process resulted in good agreement of the results yielded by both the methods.

-184- P3-23

ELEMENTAL ANALYSIS OF SELECTED SAUDI ARABIAN COINS USING ACCELERATOR BASED SLOW NEUTRONS

F. Z. Khiari, A. Aksoy, M. N. Al-Haddad Energy Research Laboratory, Research Institute, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

An accelerator-based slow neutron activation analysis facility has been recently developed at KFUPM. The facility is based on the D(d,n)3He reaction. Fast neutrons with an average energy of 2.5 MeV are produced at the KFUPM 350 keV ion accelerator by accelerating a 700 uA deutenum ion beam from the low intensity duoplasmatron ion source to an energy of 250 keV and transporting it to the end of the 0° beam line where a water-cooled solid deuterium target is situated. The fast neutrons are slowed down in a cylindrical high-density polyethylene moderator. The slow-neutron flux has a maximum intensity of 2.5xl06 n/cm2/s. For flux normalization purposes, the neutron flux is monitored on-line using a NE213 liquid scintillation detector. The detector is situated at a distance of 275 cm from the deuterium target and an angle of 90° with respect to the beam axis. The V-ray counting station is placed in a separate room and is based on a shielded HP-GMX detector which is connected to a PC based data acquisition and analysis system. The facility has an adequate thermal-neutron flux that is relatively homogeneous at the sample site and, since it is a non-destructive bulk analysis method, requires little or no sample preparation We carried out a study and found that the facility is well suited for the elemental analysis of coins. Indeed a selected number of saudi arabian coins of 10 Halala denomination dating from 1379 H - 1408 H (1958-1987 G) were each irradiated in the accelerator-based slow neutron flux for 1.5 hours and left to decay for 10 minutes The induced y-ray activities were then counted for 1.5 hours. The elements that were determined in the coins were Cu, Ni, and Mn. Calibration curves were established for these activated elements in the coins using two pure foils of each element with different weights. The 10 halala coins contained Cu and Ni in major quantities (Cu: 70-75 wt.%, Ni: 20-25 wt.%) as well as Mn in minor ( < 0.5 wt.%) quantities. Results of the experiment will be discussed. Advantages of the method with respect to other techniques such as those based on chemical analysis, reactor and 14 MeV neutron activation, as well as PIXE and X-ray fluorescence will be highlighted Details of the experiment with supporting figures and tables will be presented.

-185- P3-24

MAPPING OF TRUE COINCIDENCE EFFECT VALUE FOR VOLUMINOUS SOURCES MEASURED WITH HPGE

V.P.Kolotov, V.V.Atrashkevich, N.N.Dogadkin Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Kosygin str, 19, Moscow B-334, 117975 Russia

To compute the true coincidence effect for a voluminous source it is necessary to make an integration of the effect value over the sample volume [1]. The method developed of the correction computation is based on using as input parameters both the full peak efficiency map generated in advance and the measured intrinsic P/T-calibration. It was demonstrated that such approach works quite well for HPGe detectors with up to 60% relative efficiency [2]. It is well known that the effect value depends on the distance of the point under consideration and the detector. Applying the developed software we have reconstructed a three dimentional coincidence effect map inside the sample (cylinder, Marinelli beaker). The stability of the results with respect to input parameters is discussed. The influence of P/T-calibration variations (eg. due to radiation scattering in the sample) on the map view are also considered.

1 V P.Kolotov, V V.Atrashkevich, S.J.Gelsema. J Radioanal.Nucl.Chem., 210(1996)183. 2 V P.Kolotov, M J.Koskelo J.Radioanal Nucl Chem , in press.

-186- P3-25

NEW METHOD OF DETERMINATION OF RADIOSTRONTIUM BY USING THE SYNTHETIC SELECTIVE SORBENTS (TYPE VS-15)

A.Kovalev, S.Kozakov, V.Ribalka, A.Ermakov, V.Serbinovkh Government Enterprise «RADEC», Chernobyl; Russia Scientifwal-Practical and Expert-Analytical Centre, Moscow; Joint Venture «Khimtekservis», Odessa

At present, a lot of work has been published on using the synthetic fibrous sorbents for selective extraction of different elements. We have designed a new class of synthetic fibrous sorbents (type VS-15), which allows to develop new unique strategies of extraction of different radionuclides from mixtures of complex chemical composition. Sorbents of this type combine high selectivity of crown-ethers with good dynamic features. In the present work the strategy of extraction of radiostrontium is described using a synthetic fibrous sorbent of the type VS-15. Strontium is highly effectively absorbed on a filament from the 5.5-7.5 M nitric acid. Washing of the filament with 6.5 M nitric acid allows to separate a majority of disturbing macro- and microcomponents (97-99% of Cf, Mg, Fe, as well as artificial and natural radionuclides, including Ra). Strontium is eluted with 10-12 free volumes EDTA with pH10-12. If needed, additional cleaning of Ba and Ra traces can be performed. The total yield of strontium in all stages of analysis amounts to 75-82%. Radiochemically clean strontium sulphate is deposited to the substrate and its radioactivity is measured using a beta-counter. The time needed for the analysis is 4 hours. For the strontium determination in natural water, large volumes (80-100L) are passed through the column with lOg sorbent at the speed of 20L/hour without preliminary preparation. In this case, the yield of strontium extraction amounts to 65-75% The method was successfully used in the Chernobyl Zone for radiostrontium control and in assays of of different test samples of ground and natural water, samples of vegetation, milk, etc.

-187- P3-26

PRECISE DETERMINATION OF SILICON MACROCONCENTRATION

S.A. Makarov State Institute for Rare Metals, National Scientific Center "GIREDMET" Bol.Tolmachevsky per.5, Moscow, 109017, Russia

The possibilities of precise silicon determination by the neutron generator activation analysis (NGAA) are studied using a "SAMES" T-400 universal neutron generator with the maximum flux density of 14-MeV neutrons of 5xlO10 cm"2 s'1. The short-lived isotopes 28A1 and ^Al are used. The concentration range of silicon determination is from 1 to 70 wt % for various compounds and alloys. Due to the short half-lives of 28A1 and 29A1, the determination of silicon by fast neutron activation is subject to many inaccuracies; i.e. variation in irradiation and measurement conditions, effects of high counting rate, diverse geometric factors, interferences of gamma-lines, and other sources of errors. One of the key problems of the technique elaboration is studying and correct accounting of all possible sources of systematic errors. The ways to determine correction factors and to eliminate errors are described. The metrological characteristics of the developed procedures, such as the random and systematic errors, relative standard deviations, confidence intervals, and others are presented. A procedure for calculating the general error of results of analysis is proposed. The potential of using 2SA1 and 29A1 as analytical isotopes is shown at the silicon determination in Al-Si alloys, when 28A1 is generated from aluminum by the (n,y) reaction. The examples of results of silicon macro-content determination in various materials are given.

-188- P3-27

AN EASY AND ACCURATE METHOD FOR228 RA DETERMINATION IN RIVER WATERS BY LIQUID-SCINTILLATION COUNTING

H.Moreno, I.Vioque, G.Manj6n and R.Garcfa-Tenorio Universidad de Sevilla. Departamento de Fisica Aplicada. E. T. S.Arquitectura. Avda. ReirtaMercedes 2, 41012-Sevilla, Spain. FAX: +34-5-4557892

22&Ra activity concentration was determined in river water using a low background liquid scintillation counter Wallac Quantulus 1220. Water samples were acidified inmediately after collection. Some 500 mL of water was taken in each analysis. Radium was extracted from the samples as Ra-BaSQ) precipitate which was afterwards dissolved with EDTA at pH 9. The solution was transferred into a low potassium glass vial and then mixed with a scintillation cocktail. For a comparison, two different scintillation cocktails Pharmacia Optiphase Hisafe II and Pharmacia Optiphase Hisafe 3 have been selected. A standard solution of 226Ra was used to determine the total efficiency yield (counting efficiency multiplied by the recovery yield). The chemical procedure was applied to 500 mL of distilled water traced with a known amount of 226Ra. In this way, the mean total radiochemical yield of 60 % was found, considering the full alpha spectra. In the liquid scintillation counter, alpha and beta spectrum can be acquired simultaneously using its pulse shape analyzer (PSA). A carefull calibration study of the PSA parameter using ^'Pu and *)K standard solutions was done in order to obtain the best alpha-beta separation. Alpha spectra were used for the activity calculation. One single measurement performed one month after radium separation allows to calculate the 23SRa concentration, as well as to appreciate the presence of other alpha emitters, which are not daughters of 226Ra, in the sample. This can be checked by comparing the results obtained using the full alpha spectrum and the 214Po window of the alpha spectrum. The latter information can be used to evaluate the n4Rn concentration using an additional measurement done just after radium chemical separation. The method has been applied for the determination of 226Ra and ^Ra activity concentrations in river water collected at different places of the Odiel river estuarine area (South-west of Spain). Several fertilizer production plants release some wastes (phosphogypsum) to the estuary, containing high activity levels of natural radionuclides, e.g., radium. Therefore, it may be expected that the water contains enhanced levels of this element.

-189- P3-28

DETERMINATION OF IMPURITIES IN MOLYBDENUM AND TUNGSTEN BY INAA

N. M. Mukhamedshina Institute of Nuclear Physics, Uzbek Academy of Science 702132, Tashkent, Uzbekistan

INAA techniques for the determination of Na, K, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, As, Se, Zr, Mo, Ag, Sn, Sb, .Cs, Ba, Hf, Ta, W, Re, Au, Th, U with limit of detection from 0.1 ng/g up to 1000 ng/g in different molybdenum and tungsten products have been developed. Determination of this large number of impurities was achieved by using complex conditions of irradiation, including various neutron energies and choosing optimal time parameters. Self-shielding and disturbance of neutron flux, absorption of gamma-rays in the sample were taken into account with the help of literature data and with the help of preliminary obtained experimental results. Samples and standards have been placed in such a way that neutron flux disturbances were less than 2-3%. The contents of P and S in molybdenum and tungsten were determined by measurements of P- activity of 32P by using a p-spectrometer with an anthracene crystal (40 x 15 mm ) in the energy range of 1500 - 1700 keV To separate the 32P activity originating from P and S, the same sample was irradiated with both thermal and epithermal neutrons ( the thickness of the Cd cover was 1.0 mm). The results were obtained by solving a system of linear equations. The simultaneous determination of P and S by via 32P can be carried out if the element contents differ by not more than 1-1.5 orders of magnitude. The methods have been used to control the products of processing of refractory materials, to study the dynamics of impurities and doping elements at all stages of production process.

-190- P3-29

DETERMINATION OF POLONIUM-210 IN PHOSPHORIC ACID

T. Nakanishi1, M. Hirose1, H. Fukuda2 and Y. Goto2 1 Department of Chemistry, Faculty of Science, Kanazawa University Kakuma-machi, Kanazawa, Ishikawa 920-11, Japan 2 Materials Characterization Center, Fujitsu Laboratories Ltd. 10-1, Morinosato Wakamiya, Atsugi, Kanagawa 243-01, Japan

Soft-error rate is of great concern in the assessment of the reliability of semiconductor memory devices. Soft errors are intermittent errors that occur as a result of the passage of ionizing radiation through the memory cells of semiconductor devices. The most common source of this radiation is alpha radiation from naturally occurring alpha emitters, which are found in trace amounts in every materials used for semiconductor memory devices.l Since the finding of alpha-particle-induced soft-errors, many laboratories in the world have devoted considerable efforts to reducing the alpha emission rate from materials for fabricating semiconductor devices. Although the efforts succeeded in reducing the alpha emission rate from device packaging materials down to a level of less than 0.001 alphas cm'2 h'1, it was then found that 210Po in phosphoric acid, a common chemical for the processing of silicon wafers, can be a significant source of alpha contamination of the processed wafers.2 Although approximately 0.07 mBq ml' of 210Po contamination in phosphoric acid was estimated as the maximum allowable concentration level,2 reliable and convenient routine methods for the determination of trace 210Po in phosphoric acid have not been established, and appropriate analytical techniques for the determination of traces of 210Po in phosphoric acid have strongly been desired. In this work an analytical method was developed for the determination of trace 2ltlPo in phosphoric acid. For the determination of 21°Po in phosphoric acid, calibrated 209Po was used as a yield tracer. The present method consists of (1) addition of known amount of 209Po to 5 ml of a phosphoric acid sample followed by isotopic equilibration, (2) adjustment of the solution to pH 2 with 18 M sodium hydroxide (i.e. preparation of electrolytic solution), (3) electrodepositional separation (and preparation of the source for counting) of Po on a stainless-steel disk of a 25 mm diameter by applying a constant direct current (0.5 A) for 3 h to the electrolytic solution and (4) alpha-ray spectrometry. By the present method, more than 95 % of Po isotopes, together with 2l0Pb, were separated on the stainless-steel disk from other naturally occurring alpha emitters in the electrolyte. The minimum detectable activity of 2l0Po in 5 ml of phosphoric acid is about 0.05 mBq by counting the alpha activity of electrodeposited source for 10 days under a counting efficiency of 30%. The present analytical method was applied to the samples of commercially available phosphoric acid, and the concentration of 2'nPo in the samples for semiconductor processing were in a range from 0.01 to 1.51 mBq ml'1.

References 1. T. C. May, M. H. Woods, Proceedings, 16th Annual International Reliability Physics Symposium, (1978)33. 2. Z. Hasnain, A Ditali, Proceedings, 30th International Reliability Physics Symposium, (1992) 276.

-191- P3-30

SHORT-TIME INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

K.M.OchsenkUhn, N.N.Papadopoulos, N.D.Antoniou, G.E.Hatzakis National Centre for Scientific Research Demokritos 15310 Aghia Paraskevi, Athens, Greece

After the development of new nuclear reactor concepts, such as the energy amplifier, consiting of the combination of a subcritical reactor and a high enerdy particle accelerator with lead target for a spallation neutron source, high intensity neutron sources will continue to be available. Thus also neutron activation analysis will continue to be a valuable analytical method mainly after certain improvements, in spite of the cometition of other advanced non-nuclear methods such as ICP. One of the main improvements of instrumental neutron activation analysis is the incorporation of a loss-free counting unit into the gamma-ray spectrometry system, permitting the instrumental correction of count losses due to high dead times at high count rates [1]. This permits the measurement of short- and medium-lived nuclides in the presence of longer-lived nuclides at high count rates after short cooling times, enhancing also the analytical throughput rate. This also facilitates the automation of the analytical system with a sample changer, since in a series of unknown samples even highly radioactive samples can be measured because of the enhanced count rate range. This advanced sytem for short-time neutron activation analysis has been used for various applications, such as trace multielement analysis in ceramics for archaeometrical studies, isotopic uranium analysis of nuclear safeguards samples a.o. It is also envisaged to perform on-line short-time neutron activation analysis wiha loop at the reactor core. It should be noted that loss-free counting does notimprove the counting statistics and a dual system measuring also the uncorrected spectrum should be used to determine the uncertainty. For counting statistics improvement several other techniques, such as cyclic and cumulative activation as well as radioactive decay compensation have been applied especially for short-lived nuclide analysis, where the counting time is limited [2],

References 1. K.M.Ochsenkuhn et al., Fresemus J.Anal.Chem., 355 (1996) 382. 2. N.N.Papadopoulos et al., J.Radioanal.Nucl.Chem. 215 (1997) 103. P3-31

APPLICATION OF INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS AND X-RAY FLUORESCENCE ANALYSIS TO EXAMINATION OF THE AUTHENTICITY OF ART OBJECTS.

E.Panczyk, M.Ligfza*, L.WaliS Institute of Nuclear Chemistry and Technology, Warsaw, Poland *Academy of Fine Arts, Cracow, Poland

Technological examinations of art objects prior to their restoration and attempts to establish the authenticity of an object and its attribution are more and more popular in the circle of Polish historians of art, conservators and experts in museum management. They are aimed at establishing the origin of object, the applied materials and techniques as well as the state of its preservation. The analysis of materials is nowadays carried out with the aid of very sensitive physico-chemical methods which are often complementary to one another. In the Institute of Nuclear Chemistry and Technology in Warsaw in collaboration with the Department of Preservation and Restoration of Works of Art of the Academy of Fine Arts in Cracow and National Museum in Warsaw systematic studies using nuclear methods, particulary instrumental neutron activation analysis and x-ray fluorescence analysis, have been carried out on the panel paintings from the Krakowska-Nowosadecka School and Silesian School of the period from the XlV-XVII-th century, Chinese and Thai porcelains and mummies fillings of Egyptian sarcophagi. A number of important data on the concentration of trace elements, mainly in chalk and gypsum grounds, in lead white and -lead yellow, in clay, porcelains and mummies fillings were coIlected.These studies will provide new data to the existing data base, will permit to compare materials used by various schools and individual artists.

-193- P3-32

TRACE ELEMENTS IN SOME NEW ROMANIAN PHYTOTHERAPEUTIC DRUGS INVESTIGATED BY NEUTRON ACTIVATION ANALYSIS

A.I. Pantelica1, M.N. Salagcan1, E.A. Preoteasa1, C. Ionescu-Tirgoviste2 ^ Institute of Physics and Nuclear Engineering "Horia Hulubei", PC) Box MG-6, 76900 Bucharest, Romania -Institute of Metabolic and Nutrition Diseases "N. Paulescu ", Bucharest, Romania

Instrumental neutron activation analysis (INAA) has been used to assess the concentrations of Ai, As, Au, Ba, Br, Ca, Cl, Ce, Co, Cr, Cs, Cu, Fe, Hf, Hg, K, La, Lu, Mg, Mn, Na, Rb, Sb, Sc, Sm, Th, V, and Zn in four new Romanian phytotherapeutic drugs registered as Fitolip, Fitodiab, Retinomion and Neuromion. These phytotherapeutic drugs were selectively prepared of fruits, flowers, leaves and shells of twelve plants used in non-conventional medicine. Clinical trials showed that the drugs are very well tolerated and that their activity is directed mainly towards the lowering of lipids (Fitolip) and of glucose (Fitodiab), the prevention of retmopathic complications (Retinomion), and the treatment of diabetic neuropathies (Neuromion). Percent levels of Mg, K, thousands of ppm of Ca, thousands to hundreds of ppm of Cl, Na, Al, hundreds of ppm of Fe, hundreds to tens of ppm of Mn, tens of ppm of Zn, about ten ppm down to one ppm of Ba, Rb, Br, Cu , Cr, hundreds of ppb of V, Co, Ce, La, tens of ppb of Au, As, Hg, Cs, Sc, Sb, Th, Sm, Hf and ppb level for Lu have been observed. The therapeutic value of the microelement content in the drugs is discussed based on a comparison to the daily necessary intake.

-194- P3-33

NEUTRON ACTIVATION ANALYSIS OF SEA BUCK-THORN (HIPPOPHAE RHAMNOIDES) MEDICINAL PLANT

M.N. Salagean1, A.L Pantelical, I.I. Brad2, C.A. Rusu1 ^Institute of Physics and Nuclear Engineering "Horia Hulubei", PO Box MG-6, 76900 Bucharest, Romania ^•Faculty of Biology, University of Bucharest, Romania

Sea buck-thorn medicinal plant (Hippophae rhamnoides) contains various mineral substances, essential macro- and micro-elements besides proteins, glucides, fatty acids as well as important quantities of essential aminoacids, vitamins (C, Bi, B2, Bg, B12, E, F, P), serotonins, carotenoids and enzymes. Due to many active physiological substances with beneficial effect for human beings and animals this excellent therapeutic plant is used both as a food (tea, preserves) and in the pharmaceutical industry (parts of the plant are used to obtain oil, hydrosoluble extract or, together with other medicinal plants as a component of some non-conventional drugs). Therapeutical action of sea buck-thorn is directed mainly in wounds, burns, hepatic diseases and vitamin deficiency cures. To determine the trace and micro-element content of this plant, ashes of leaves and fruits as well as a hydrosoluble fruits extract were analysed by instrumental neutron activation analysis (INAA) method at the VVR-S reactor in a neutron flux of 2.3xlO!2 cm"2s'!. The concentration of Al, As, Au, Ba, Br, Ca, Cl, Ce, Co, Cr, Cs, Cu, Eu, Fe, Hf, K, La, Mg, Mn, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Th, U, V, Yb, and Zn is presented The biological role and therapeutic action of several of the analysed elements is discussed.

-195- P3-34

NEUTRON ACTIVATION ANALYSIS OF SOME BUILDING MATERIALS

M.N. Salagean1, A.I. Pantclica1, I.I. Georgescu2, M.I. Muntean2 ' Institute of Physics and Nuclear Engineering "Horia Hulubei", PO Box MG-6, 76900 Bucharest, Romania ^•University "Potitehnica ", Faculty of Industrial Chemistry, 1 Polizu Street, ~H122 Bucharest, Romania

The elemental composition of building materials is of interest with respect not only to the induced indoor radioactivity, but also as concerns toxic elements, such as As, Sb, Zn. In the present paper, the concentrations of As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La , Lu, Mo, Na, Nd, Rb, Sb, Sc, Sr, Ta, Tb, Th, U, Yb, W and Zn in some Romanian building materials were determined by Instrumental Neutron Activation Analysis (INAA). The building materials analyzed are: raw material (75% limestone, 25% clay) used in the production of cement, cement samples from three different sites, furnace slag, phosphogypsum and a brick fabricated at a pressure of 40MPa at 20°C from slag, fly coal ash, phosphogypsum, lime and cement. The fly coal ashes from five Romanian coal-fired power plants, resulting from combustion of xyloide brown coals, lignite and bituminous- subbituminous coals were previously analyzed One can observe a lower concentration of Au, As, Br, Sb, Zn and a higher concentration of Ca, Ba, Cr, Sr, Ce, Eu, Th in cement samples in comparison with raw material. The rather high content of Co, Cr, Th, U and Zn in brick is especially due to fly coal ash and slag, those being the most important components of the brick. The U and Th concentrations in the final bricks are in good agreement with the natural radioactivity measurements of 226Ra and 232Th.

-196- P3-35

QUALITATIVE AND QUANTITATIVE ANALYSIS OF MEDIEVAL COINS STRUCK UNDER THE RULE OF MATHIAS BY EDXRF

Zsuzsanna Sandor, Sandor Tolgyesi, Ivan Gresits, Laszlo Jarosi, Jozsef Solymosi, and Marta Juhasz Kaplanne* Technical University of Budapest *Hungarian National Bank

Energy-Dispersive X-Ray Fluorescence technique was applied for analysis of silver coins to determine the elemental composition in a fast and nondestructive way. The non-destructive feature of analysis is very important when is not possible to destroy the structure of the ancient, precious coins. In the present work we have developed a quantitative method for samples with different size and geometry. This method was employed for coins with two components, Ag and Cu, where the content of the trace elements is under 0.1%. AH the coins and the standards were exposed from an annular I source; the X-ray radiation was measured using a Si(Li) detector with associated electronics and a multichannel analyzer which was coupled to a computer. The usefulness of the method has been confirmed by analyzing certified silver alloys. The agreement between the measured and the true values is good The precision that is indicated by the relative standard deviation (RSD %) is under ±4 %. Silver coins were analyzed from the collection of the Hungarian National Bank, struck in Hungary during the reign of Mathias (1458-1490). In our contribution we present the concentration values of the main components and a list of trace elements present in coins.

-197- P3-36

GAMMA-SPECTROMETRIC ANALYSIS OF ENVIRONMENTAL SAMPLES OF COMPLEX COMPOSITION

I.A.Savushkin, A.M. Ragotner, A.V. Lukjanov, O.B. Gourko Institute of Power Engineering Problems/National Academy of Sciences of Belarus

Radiation monitoring of environmental conditions is based first of all on obtaining of true primary data - results of radionuclide analysis of object samples. Performing of such analysis has some special features associated with different physical and chemical characteristics of the sample composition such as inhomogeneity of a distribution of radionuclides in the measured samples, the absence of a complete set of their metrological standards. Moreover, it may be quite expensive to take all appropriate measures in the cases of accidents at nuclear installations. After the Chernobyl NPP accident the problem of the development of a method for rapid on-line analysis of a large amount of samples became very important. One of the possible methodologies of radionuclide gamma-spectrometric analysis is discussed in this paper in terms of sensitivity and accuracy of this method. The real sensitivity for specific applications and different measuring geometries is evaluated, as well as problems of measurement of inhomogeneous samples. The relative error and reliability of radionuclide gamma-spectrometric analysis results and the sensitivity of the method is calculated. The application of the developed method to the analysis of building materials is also considered. The method proposed allows to carry out radionuclide analysis of environmental samples of a complex configuration and composition with a high degree of accuracy and sensitivity. It is based on a large amount of the primary material which has been analyzed by the scientists of "Belarusgeology", Nuclear Power Engineering Institute/Academy of Sciences of BSSR, Institute of Power Engineering Problems/ National Academy of Sciences of Belarus. This methodology may be recommended for the establishment and development of an environmental radiation monitoring system.

-198- P3-37

INVESTIGATION OF TRACE ELEMENTS IN CLAY MINERALS BY NEUTRON ACTIVATION ANALYSIS

M. Samareh Shahpasand Physics Department, Kerman University, Kerman, Iran

This report is about using fast neutron activation analysis technique to determine the concentration of some elements in clay minerals by 14 MeV neutron activation analysis.

-199- P3-38

NEUTRON ACTIVATION ANALYSIS OF NATURAL WATER APPLIED TO HYDROGEOLOGY

M. Samareh Shahpasand Physics Department, Kerman University, Kerman, Iran

The analysis of trace elements in ground water samples has been used to examine such hydrogeologic problems as the quality and capacity of water supplies, the origin and existence of ground water streams and ground water exchange with rivers. Examples of the activation analysis data for the determination of the origin of water from wells will be given.

-200- P3-39

DETERMINATION OF SOME TRACE ELEMENTS IN THE SERUM OF THALASEMIA DISEASED USING NEUTRON ACTIVATION ANALYSIS, PIXE AND ICP

M. Samareh Shahpasand, A. Molla (Fathemy) - Fatbizadeh Physics Department, Kerman University, Kerman, Iran

The increase of some trace elements like Fe in the blood serum of Thalasemia diseased, can cause very intense disorder in the metabolism Using desferal as a chelate complex binding agent, the amount of Fe and other elements in the blood can be controlled. In this paper, the determination of some trace elements in the blood serum of Thalasemia patient after injection of desferal is reported. The blood samples collected from Ali Asghar Hospital were analysed using neutron activation analysis and gamma - spectroscopy The results were compared with data obtained by PIXE and ICP method. The results obtained in this study can be used in diagnosis and treatment of Thalasemia patients.

-201- P3-40

NEUTRON ACTIVATION ANALYSIS AS AN USEFUL INSTRUMENT TO SOLVE SOME COMPLICATED QUESTIONS OF THE ENVIRONMENTAL STATUS

Irina Shtangeeva Institute of Earth Cmst, St.Petersburg University, Universitetskaya nab., 7/9, St.Petersburg 199034 Russia

Environmental samples are traditionally complicated objects for elemental analysis. This is due to the fact that in most environmental samples very low concentrations of many trace elements are observed. In addition, most analytical techniques require different sample preparations. In this connection, instrumental neutron activation analysis is probably the only exception from the indicated rule. NAA allows to determine concentrations about 40 chemical elements (trace elements, different heavy metals and also biologically essential elements) in different environmental samples (water, soils, plants and many others) with the high sensitivity and accuracy. In this case all samples can be analysed in their natural state without any treatment. In our work chemical element redistributions among soil and different parts of some species of plants were studied. It was found that concentrations of different chemical elements have peculiar features of given species of plants. In the natural conditions mean concentrations of chemical elements in plant leaves or roots can remain sufficiently constant, whereas under environmental pollution significant variations not only in plant elemental composition, but also in some physiological functions were found. In most cases, strong changes were observed for plant roots. In our experiment it was also shown that an increase in environment concentration of any one toxicant can lead to significant variations in the whole elemental composition of plants, including biologically essential chemical elements. In this case, concentrations of many elements important for plants can significantly be decreased. On the other hand, an increase of concentrations of different chemical elements in the environment can simultaneously lead to both increased and decreased (in some cases) element concentrations in plants.

-202- P3-41

RADIOCHEMICAL METHODS FOR THE DETERMINATION OF 55 63 210 210 234 238 239+240 Fe, Ni, Po, Pb, U, U AND PU IN THE ENVIRONMENTAL SAMPLES

Bogdan Skwarzec Polish Academy of Sciences, Institute ofOceanology ul. Powstancow Warszawy 55, 81-712 Sopot, Poland

Radiochemical procedures are described for the determination of natural (210Po, 210Pb, ""U and ^'U) and artificial (55Fe, 63Ni, 238Pu, "'Pu and 240Pu) isotopes in environmental samples (water, sediment and biological material). The methods are based on coprecipitation of polonium, lead, uranium and plutonium with manganese dioxide from natural water, mineralisation of sediment and biota samples, and sequential separation and purification of the radionuclides on anion exchange resin. The individual elements are electrodeposited on silver (polonium) or electroplated onto steel discs (uranium and plutonium) or copper discs (iron and nickel). The activities of 210Po, 234U, a8Pu, a9Pu and 240Pu are measured by alpha spectrometry with low-level- activity silicon detectors. The 210Pb activity was estimated on the basis of 210Po ingrowth after the lead fraction was purified and stored for some months. The activity of "Fe and 63Ni was measured by beta spectrometry using an anti-coincidence GM gas flow counter. A high recovery of these radionuclides was verified using certified reference materials.

-203- P3-42

ESTIMATION OF THE REPRESENTATIVE SAMPLE MASS IN NEUTRON ACTIVATION ANALYSIS

L.A. Smakhtin Obninsk Branch Karpov Institute of Physical Chemistry

Equations are derived to associate the mass of a representative sample and such components of the total variance, which characterizes the dispertion of results of neutron activation analysis (NAA), as the variances of nonuniformity and replicate reproducibility. A method is proposed for approximate estimation of the minimum mass of the representative sample in the NAA of inhomogeneous materials.

-204- P3-43

THE MAIN DIRECTION OF DEVELOPMENT OF NUCLEAR-PHYSICAL METHODS OF ANALYSIS FOR SCIENCE AND INDUSTRY OF KAZAKSTAN

V.V. Sokol'sky, V.P. Solodukhin, I.V. Kazachevskiy Institute of Nuclear Physics, National Nuclear Centre, Republic ofKazakstan (INP NNC RK)

A need for the development of nuclear-physical methods of analysis (NPMA) in Kazakstan is dictated by the necessity to solve a great number of analytical tasks connected with industrial, economical and social problems of the country. The main criterion for the choice of NPMA application fields has always been the rational use of their advantages in comparison with traditional chemical, physico-chemical and physical methods of analysis. Such advantages are: high sensitivity, multielementality, the possibility to carry out analysis without destruction of sample, in some cases it is a highly proximate method and has a high productivity. Historically, the development of the NPMA in the INP has begun in the sixties with the development of activation analysis (AA) using the nuclear reactor "WWR-K" and the isochronous cyclotron. Another set of experimental devices was designed and manufactured specially for AA. These are: a neutron generator with continuous operation using a mixture of deuterium and tritium; an Sb-Be source of neutrons; an ironless toroidal beta-spectrometer of the type "Orange"; an automatic device for determination of oxygen in Balkhash copper and other objects; a set of pneumatic transportation devices at the reactor, of which one is used for uranium determination by the method of delayed neutrons (MDN). In spite of apparent advantages of AA, such as low element detection limits (10"2 -rlO"4 ppm), this method is, in most cases, very expensive, labour- consuming and requires a high qualification of the personnel. Therefore, X-ray fluorescence analysis (XRFA) has also been developed in the INP. From the point of view of detection limits (10 + lppm) the latter method is considerably worse than AA. However, it is a proximate method, cheaper, more simple and can be used to carry out mass analyses. The techniques developed in the INP, including all possible chemical and physical ways of sample treatment (preliminary concentration, use of strong-current roentgen tubes, focusing lenses, re-emitters and others) allowed to decrease the detection limits of many elements up to n-10"2 ppm. An essential addition to the above mentioned methods is atomic emission spectroscopy with inductively coupled plasma (AES-ICP) developed in the INP on the basis of spectroanalyser "GY-70p". From the point of view of the detection limits (10"' +10"2 ppm), this method is comparable with AA, moreover it fills some gaps of AA allowing to determine the elements non-accessible by AA, such as Pb, Bi, Si and others. In following years, in connection with the intensified radiophoby, other methods for analysis of radionuclides have been developed in the Institute based on different ways of radiochemistry and alpha-, beta- and gamma-spectrometry. In total, all enumerated methods provide possibilities to carry out both mass analyses and performance of fine scientific research. A great number of analytical tasks connected with archaeology, criminalistics, medicine, biology and agriculture has been solved. But main achievements were obtained in metallurgy - analysis of pure and suprapure materials; in geology - prospecting and calculation of stocks of mineral resources; in ecology and radioecology - control of environmental objects in industrial regions and at locations where nuclear tests were carried out (SNTS, "Azgir", "Lira", "Batolit" and others). Research carried out in the INP on improvements and applications of nuclear-physical methods of analysis in different fields of science and national economy ofKazakstan are supported by the IAEA and the ISTC

-205- P3-44

X-RAY SPECTROMETRY OF TRANSURANIUM RADIONUCLIDES IN THE SAMPLES OF THE ENVIRONMENT

E.D.Stukin1, M.D.Bondarkov2, V.A.Zheltonozhsky2 'institute of Global Climate and Ecology, Russia ^Institute of NuclearRresearch, Ukraine

As a result of accidents at NPP a lot of fuel-containing materials penetrates into the environment. There is a lot of transuranium radionuclides (U, Np) in fiiel-containing materials. It is a specific characteristics of the accident at the Chernobyl NPP. Plutonium content in the environment is one of the important factors, influencing the formation of dose loads, but also one of the major factors of the risk resulting in various cancer diseases. At the same time, plutonium isotopes are the most difficult for measurements. It is caused by both the absence of y-quanta in the plutonium decay, and affinity on energies of a- particles from the 239"240Pu decay In general, the 241Pu isotope is practically not defined, since it decays only by P-transition with the energy of 20 keV. We carried-out a study of Irradiation in 238 24O 239 238 240 the - Pu and Pu isotopes. It was observed, in particular, La( ' Pu) is equal to 5 %, 239 Ln( Pu) is equal to 1,1 %. The energy of La-radiation is equal to 13.6 keV, and with such energies it is possible to carry out measurements with "thick" targets. To detect the 241Pu activity, the process of atom ionization was investigated by p-decay. In this study La-radiation of americium was observed for the first time, which was caused by the process of ionization of L3- shell of americium by p-decay 241Pu. 241 The radiation of LaU (13.6 keV) and Am with y-line of 59.4 keV, and Lo,(13.9) which is always present in the spectrum Heterogeneity of the target affects the L(U)/La(Np) ratio slightly, due to the close energy, and we can detect the activity of plutonium isotopes through the 59.4 keV y-line of 24lAm. This allows to increase the accuracy of such measurements by order of magnitude. This method is of special interest in determining the time of campaign of fuel rods (x), since 24I Ti 2( Pu)=14 years, and its operating time is the most sensitive to x.

-206- P3-45

RAPID METHOD FOR THE DETERMINATION OF MSr IN THE PRESENCE OF 137Cs IN CONTAMINATED SAMPLES

J.M.Torres, J. Tent and G. Rauret

Dept. de Quimica Analitica, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain

A laboratory approach in the study of radiostrontium and radiocaesium behaviour in soil-plant systems is useful for modelling and field studies of soil-to-plant transfer. The isotopes most widely used for this kind of studies are 85Sr and l34Cs. However, when dealing with long-term experiments '"Sr and !37Cs are required. In these cases the determination of the '"Sr activity concentration introduces time-consuming steps, like a sample preparation, radiochemical separation or yield determination, and therefore obtaining of data is difficult. The use of new methods of sample preparation (microwave digestion) and radiochemical separation (liquid-liquid extraction and chromatographic procedures) may lead to the shortening of the analytical procedure, although the time required for the total determination is still high. In this work a mathematical model, which avoids the radiochemical separation step, was developed for the determination of '"Sr from its progeny '"Y by the Cerenkov counting technique in samples which contained 137Cs. For this purpose, a set of standards which ranged from the pure '"Sr/^Y and l37Cs radionuclides to binary mixtures of both radionuclides was prepared. A total of 50 standards were considered and their activity varied from 0 to 500 Bq for each radionuclide. These standards were measured from 10 minutes to 1 hour depending on their activity. A multiple variable regression without constant was performed from the data and the fitted model (the R2 statistics = 0.99997, a confidence level = 99%) was the following:

'"Sr activity (dpm) = 1.052 x activity measured (dpm) - 0.119 x 137Cs activity (dpm)

This model was applied to soil and plant samples and extracts obtained from them which contained different ^Sr and B7Cs activities. The sample activities ranged from 4 to 540 Bq for '"Sr and from 2 to 1400 Bq for "7Cs. The "Sr/'^Cs activity ratios in the samples used ranged from 0.5 to 8 The '"Sr activity obtained by applying the fitted model was compared with the activity obtained from the radiochemical separation method. The good correlation found between the two methodologies (the R2 statistics = 0.997, the confidence level = 95%) proves that the fitted model is useful to determine the wSr activity in presence of 137Cs and, consequently, reduces the time of sample processing, about 2 hours, since no radiochemical separation is needed.

-207- P3-46

THE DETERMINATION OF LOW LEVEL ALPHA ACTIVITY IN TOBACCO

Giinseli Yaprak*, Cafer Celikdad*, N.FUsun Cam** * Ege University, Institute of Nuclear Science, 35100 Bornova-Izmir, TURKEY **Ege University, Faculty of Science, Department of Physics, 35100 Bornova-Izmir, TURKEY

Naturally occuring a-active radionuclides in tobacco and in smoke have been studied to identify carcinogenic agents. Considering the large smoking population, it is therefore of interest to determine the alpha activities in cigarette tobaccos. In the present study CR-39 solid state nuclear track detectors were used to determine alpha emitters in cigarette tobaccos. The tobacco samples were pressed into discs and were then exposed to CR-39 for recording the alpha tracks. After exposure the detectors were etched in a 6.25 M NaOH solution at 70°C for 16 hours and then were analyzed using an optical microscope. The relatively new detection technique requires only to bring the specimen into contact with the alpha track detector and leave it for the required time. In this method, the long exposure times have been used to determine low levels of alpha emitters in the samples.

-208- P3-47

NEUTRON ACTIVATION ANALYSIS OF HUMAN HAIR

L.I. Zhuk, A.A. Kist Nuclear Physics Institute, Ulughbek, Tashkent, 702132, Uzbekistan, CIS

Neutron activation analysis (NAA) is an outstanding analytical method having very wide applications in various fields. In the last decades, analysis of human hair, mostly performed by NAA, appeared as a very attractive application of the technique. It is commonly known that the elemental status of human body changes with changes of the physiological status e.g. in some diseases. There are many studies which detected specific changes of elemental composition of human tissues and body fluids. Changes of the elemental composition of human hair are very significant besides those in other tissues. The present work gives a brief overview of some recent results in this field which include the application of hair analysis for environment monitoring, mapping of endangered areas or cities, occupational medicine, detection of the groups at risk, and early diagnosis of diseases

-209- P3-48

EXPERIMENTAL TECHNIQUE FOR DETECTION OF INDUCED GAMMA EMISSION IN TRANSITION Te(125m,2)->Te(125m,1)+gamma(109,27keV)

B.E. Dzevitskii, G.A. Skorobogatov Dept. of Chemistry, St. Petersburg State University, Petrodvorets, 198904 St. Petersburg, Russia

We present a series of experimental details for the observation of an induced gamma emission in the M4 transition [1,2].

Te(125m,2)+gamma(109.27 keV) -> Te(125m,l)+2 gamma(109.27 keV).

At first, we studied the dependence of the value of the effect measured on lower level of stability (or non-stability). Secondly, we offer the optimal way for -125m(2) preparation in concentration just higher than 1021 atoms per cm3. Thirdly, we studied a dependence of the measured effect value on the type of solid matrix containing the tellurium - 125m(2). Fourthly, we propose to combine special filters which permit to separate the 109.27 keV gamma radiation and double-energy 218.54 keV quanta under investigation from bremsstrahlung and other background radiation. In the fifth place, we propose to use appropriate types of a preamplifier, detector, and other electronic units of the experimental setup.

References: [1] G.A. Skorobogatov, BE. Dzevitskii, Izvestija Acad Sci. USSR, Ser. Phys. (Russ), 1984, Vol. 48, No. 10, p. 1934-1939 [2] G.A. Skorobogatov, B.E. Dzevitskii, Laser Physics, 1995, Vol. 5, No.2, p.258-267.

-210- P3-49

PRECONCENTRATION OF TRACE METALS IN SEA WATER AND ITS DETERMINATION USING NUCLEAR-RELATED ANALYTICAL TECHNIQUES

Pedro Lam Ramos, Juan R. Estevez Alvarez, Alfredo Montero Alvarez, Ivan Pupo Gonzales Centra de Esludios Aplicados al Desarrollo Nuclear (CEADEN)

Some methods for enrichment and separation of Fe, Co, Ni, Zn. Pb and Cu in sea water using the chelating resin CheIex-100 or the complexing precipitant APDC as reagents are described. The selectivity of the preconcentration techniques used for these trace metals has been studied using a synthetic sea water containing spiked amounts of these elements. The influence has been considered of alcaline and alcaline earth metals on quantitative determination of the heavy metals investigated. The Energy Dispersive X-Ray Fluorescence (EDXRF), Total Reflection X-Ray Fluorescence (TXRF) and Stripping Anodic Voltametry (SAV) have been used for the final measurements. A preliminary assessment on feasibility of the methods developed for the analysis of trace elements in seawater at the Cuban coast is discussed

M&XT PAGE(S) S@ft BLANK -211- Topic 4

IONISING RADIATION IN SCIENCE, TECHNOLOGY, AND MEDICINE

Verbal presentations

-213- CZ9827822

RADIATION AGEING OF POLYMERS

B. BartoniCek, V. Hn*t, V. PlaCek Nuclear Research Institute Rezplc, 250 68 Re:, Czech Republic

The widespread use of nuclear technology has made the study of the effects of ionizing radiation on materials a very important topic, not only for applications in nuclear power plants, but also in radioactive waste disposal, fuel reprocessing plants and related research facilities. Materials based on organic polymers are widely used in nuclear technology because many advantages make them attractive for various applications including cable materials, coatings, seals, containers and many others. Polymers are used extensively as insulation and jacketing materials for cables. Cable integrity is of particular importance where safety instrumentation is involved. The condition of polymer-based cable materials can be best characterized by measuring elongation at break of their insulating materials. From practical point of view, the use of differential scanning calonmetry technique and of density gradient column technique is disposable for an assessment of the cable lifetime. The results obtained with cables used in nuclear power plants are presented.

-214- CZ9827823

ULTRAVIOLET AND INFRARED SPECTRAL ANALYSIS OF IRRADIATED POLYPROPYLENE FILMS: CORRELATION AND POSSIBLE APPLICATION FOR HIGH DOSE RADIATION DOSIMETRY

A.A. Abdel-Fattah, F.I.A. Said, M. EI-Kelany and A.A. El Miligi National Centre for Radiation Research and Technology, AEA, P.O. Box 29, MadinatNasr, Cairo, Egypt

A detailed study was performed to develop the dosimetnc characteristics of commercial polypropylene film (PP), to be used as a film dosimeter for high-dose gamma radiation dosimetry. The useful dose range of this polymeric film extends up to 630 kGy. Correlations were established between the absorbed dose of gamma radiation and the radiation-induced changes in PP measured by means of Fourier transform infrared (FTIR) and ultraviolet (UV) spectrophotometry. The results showed a significant dependence of the response on the selected readout tool of measurements - FTIR (at 1716 and 3400 cm"1) or UV (at 275 nm), as well as on the quantity used for calculation. The radiation-chemical yields of the ketonic carbonyl group and the hycjroxyl group produced in irradiated PP film were evaluated. G(>C=O) was found to be 1.37 umol/J and G(>C-OH) was found to be 0.638 u,mol/J. The assessment of random uncertainty associated with the measurement of dose response and the effect of relative humidity during irradiation on dosimeter performance as well as post-irradiation stability at different storage conditions will be discussed.

-215- CZ9827824

CHARACTERIZATION AND APPLICATION OF RADIATION GRAFTED MEMBRANES IN WASTE TREATMENT

El-Sayed A. Hegazy*, A. M. I. AH**, H.Abdel-Rehim*, H. G. Nowier** and H. F. Aly** * National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo, Egypt. ** HotLabs. Center, Atomic Energy Authority, P.O. Box 13759, Inshas, Egypt.

Ionic membranes were prepared by radiation-induced grafting of acrylic acid onto low density polyethylene films. To elucidate the possibility of practical use, a study has been made for the characterization of the grafted and chemically treated membranes. The selectivity of such prepared membranes towards the chelation or complexation of different alkali metals was investigated, to find that the higher affinity is observed for K\ Na* and Li+ ions compared to other alkali metals used. The metal uptake percent was determined using different techniques; flame photometer and X-ray fluorescence (XRF). The uptake of metal from its feed solution by the grafted membrane increased as the degree of grafting increased, i.e. it is directly proportional to the content of functional carboxylic acid groups in the graft copolymer. As a consequence, the electrical conductivity of metal feed solution decreased during such process of metal chelation by the membrane. The higher the grafting degree of membrane, the lower the electrical conductivity of metal feed solutions observed. The changes in thermal properties of the prepared membranes were investigated and characterized using differential scanning calorimeter (DSC), and thermal gravimeteric analysis (TGA). The thermal stability of these membranes increased with degree of grafting due to the formation of crosslinked network structure via hydrogen bonding. Furthermore, such stability is enhanced for the alkali-treated membranes even at high elevated temperatures. The prepared membranes showed a great promise for possible use in the recovery of Uranium from Zirconium in their wastes.

-216- CZ9827825

PREPARATION OF RESPONSIVE HYDROGELS USING IRRADIATION

M. Ilavsky1, M. Refichov^2, G. Mamytbekov3 and Z. Sedlakovsi4 ' Faculty of Mathematics and Physics, Charles University, 180 00 Prague 8, Czech Republic 2 Artim s. r. o, 102 27 Prague 10, Czech Republic 3 Institute of Chemical Science, Academy of Sciences of the Kazakh Republic, Almaty, Kazakh Republic 4 Institute ofMacromoIecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6, Czech Republic

Ionic networks, copolymers of l-vinyl-2-pyrrolidone with ionic comonomer (S) - N, N-dimethyl-N, N-diallyl ammonium chloride - (mole fraction of salt x, = 0 - 0,27) in the presence of various amount of crosslinker (C) - ethylidene-bis-3( l-vinyl-2-pyrrolidone) -(mole fraction of salt x^ = 0,02 - 0,01), and redistilled water were prepared by radiation polymerization. Various amount of all three ingredients were dissolved to a 100 ml aqueous solution (volume fraction of monomers vm = 0,05 - 0,13), and the solutions were flushed with nitrogen. The ampoules of diameter D* = 10 mm were used as polymerization reactors The tubes were placed in a y-irradiator (Co60, Artim Prague) with a fixed dose rate of 0,8 kGy/h and left for required polymerization time to obtain dose y at room temperature. The swelling and mechanical behaviour if ionized networks was investigated in water- acetone mixtures. In the range x, S phase transition (collapse) was observed; while the critical acetone concentration in the mixture at collapse a,; = 76 vol. % is independent of xs the extend of collapse (jumpwise change in the gel volume). A, increases with increasing salt concentration. The jumwise change in the gel volume is accompanied by a sirmlair change in equilibrium modulus.

-217- CZ9827826

IONIZING RADIATION IN THE FIELD OF HYDROGELS USED FOR AGRICULTURE AND MEDICINE

M.Radoiu', D.Martin1, M.Dragusin2, R.Moraru2, C.Oproiu1,1.Indreias1, M.Toma1, A.Manea3 ' National Institute for Laser, Plasma and Radiation Physics, Bucharest, Romania " National Institute for Physics and Nuclear Engineering, Bucharest, Romania 3 Institute for Food Research, Bucharest, Romania

The hydrogels, such as homopolymers of acrylamide (AHH type), co-polymers of acrylamide-natrium acrylate (ANACH type) and homopolymers of natrium acrylate (NAHH type), obtained by gamma ray and accelerated electron beam are presented. The effects of the solution chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of these hydrogel types are discussed. Distilled water, physiological serum and 4 N NaCl aqueous solution were used as swelling medium. Radiation absorbed dose has an important effect upon the swelling degree of AHH and ANACH types especially when distilled water is used as swelling medium while the NAHH swelling degree presents a small dependence versus absorbed dose for all swelling medium types. Usually, the swelling degree for all hydrogel types decreases versus absorbed dose and absorbed dose rate and exhibits the higher values for distilled water as swelling medium. The hydrogels mechanical strength exhibits a maximum value versus absorbed dose. The best values for mechanical strength depend on hydrogel type and swelling medium. The used range for absorbed dose was from 2 kGy to 16 kGy. Our types of hydrogels were developed for some applications such as in agriculture (AHH and ANACH types) to maintain soil humidity and in medicine as absorption material for dressing (NAHH types)

-218- CZ9827827

THE IONISING RADIATION EFFECT ON PHYSICO-CHEMICAL PROPERTIES OF ORGANOSILICON OILS A.P. Krasnopyorova Research Institute for Chemistry of Kharkov State University, 4, Svobody sq., 310077, Kharkov, Ukraine

The organosilicon polymeric oils are widely used as a heat carriers in aviation, nuclear and space technology. Their resistance to various damage factors of outer space is a property of great importance. The gamma radiation is one of the most essential damage factors. The structure of molecules being exposed to gamma radiation may be transformed substantially. This results in variation of their physico-chemical properties. So, the laboratory modelling of the irradiation effect on the physico-chemical parameters of the organosilicons is very urgent. In this work, the physico-chemical characteristics of organosilicon oils, as dielectric constant, viscosity, and refractive index, have been measured before and after the gamma irradiation with the doses of 103 to 106 Gray. The organosilicons studied were PMS-1, PMS-5, PMS-VV, and PMFS. All the measurements were performed at the original research instrument «ISSLEDOVATEL» (investigator) with 60Co in open test tubes as a source of gamma radiation. The structure modifications in oil molecules depending on irradiation dose have been studied with IR spectrometry. When comparing the main characteristics of the studied organosilicons before and after the irradiation one may arrange them into the following sequence with the increasing of their resistance to the gamma radiation:

PMS-VV < PMS-1 < PMS-5 < PMFS

Among them, the PMFS demonstrates nearly perfect stability of all its physico-chemical characteristics with no dependence on the irradiation dose. The viscosity is appeared to be the most sensitive characteristics of radiative changes in the species studied. In particular, the substantial dependence of viscosity on the irradiation dose was found for the species of high viscosity (PMS-1, PMS-VV) having n. values of 100 spz and above. The viscosity of the PMS-VV oil increases with the dose up to the complete hardening of the sample at 106 GRay. For the liquids PMS-1 and PMS-VV it is found that the increasing of their viscosity with the dose absorbed obeys exponential law:

v = v0 • e " , where Vo and V are the viscosities of the sample before and after the irradiation, respectively; D is the absorbed radiation dose; Ky is the radiation damage factor.

-219- CZ9827828

THE USE OF GAMMA RAYS FOR THE DESTRUCTION OF SOME ORGANIC INGREDIENTS PRESENT IN WATER AND WASTEWATER PART II

Abdel Gawad A.S., Abdel Fattah A.A., Ibrahim S. AH Z.I. Atomic Energy Authority, Cairo 101, Kasr EL Eini St.

A systematic study on the use of gamma rays for the destruction of organic ingredients present in water and wastewater was carnd out. The effect of gamma rays on two organic dyes in a distilled water medium was studied at vaned dye concentration and at different dose rates and pH of solution. The kinetics of the decolouration process was also studied and it was found to follow a first order reaction. In all cases the G-value was calculated as a function of irradiation dose The investigations were extended to dye solutions in wastewaters originating at the textile factory. The difFerent factors affecting the decolouration percentage in case of wastewaters were studied The G—values were determined and the kinetics of the degradation process were established It was observed that the rate of the degradation reaction in case of wastewater was slower than the case of distilled water It is planned that work is to be extended to conditions simulating natural conditions of wastewaters released from the textile industry.

-220- C29827829

ALPHA RECOIL PHENOMENA USED FOR RADIOLABELLING OF SURFACE LAYERS OF SOLIDS £. Jech The J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Praha 8, Dolejskova 3, Czech Republic

In the natural radioactive series various radionuclides are produced by sequential alpha decays during which daughter nuclei are borne with recoil energy of about 100 keV. This phenomenon can conveniently be exploited for injection of the daughter nuclei into the surface layers of solids which thus become ,,surface labelled" . Two simple procedures can be used to realise the surface labelling. The first consist in bombardment of the surface to be labelled with a radioactive recoil nuclei in vacuum from a very thin source of a parent nuclides (such as 226Ra or 228RdTh). The second possibility is a two stage procedure during which first the positively charged ,,A" products from the air (where they have been produced by alpha decay of 222Rn or 220Tn) are electrostatically collected on the surface to be labelled. There they are allowed to decay so that the atoms of the ,fi" products are recoil injected into the surface layer up to a depth of several tens of ng/cm2. Experimental arrangements used for realising such a surface labelling is described and typical yields and depth distributions are indicated and examples of practical applications discussed.

-221- CZ9827830

EFFECT OF POLONIUM ALPHA-RADIATION ON AQUEOUS SOLUTIONS (THE HISTORY OF FRENCH AND RUSSIAN STUDIES)

M.V.Vladimirova SSNBochvar VNIINM, 5 Rogov st, Moscow, 123060, RF

Since Pierre & Marie Curie's discovery of polonium and radium the effect of their radiation on chemical systems was noted. This gave rise to a new science - radiation chemistry. Systematic studies of radiation effects go back to the mid-1940s. The effect of y- and x-rays radiation was studied most, while only M.Curie's laboratory in France was concerned with a-emirting polonium and radon. M.Haissinsky, M.Lefort, P.Bonet-Marry, M.Anta pioneered this activity. Radon was soon abandoned in favour of polonium recovered from RaD. With its short half-life, polonium is an ideal emitter which at its low content by weight produces a highly intensive radiation. French scientists determined radiation yields of H2, O2, H2O2 and that of water radiolytic decomposition, G[-H2O]. The latter was found to be equal to 3.5 molecule/100 eV and much less than that fcom •y-radiolysis (4.2 molecule/100 eV). It should be noted that the polonium recovered from RaD contained a variety of impurities influencing the yield of radiolysis products formed. From the outset of her study in 1957, the author of this paper used the purest polonium recovered from reactor-irradiated Bi-209. This made it possible to define the yields from a-radiolysis of various aqueous solutions more exactly. Relying on the J.Pucheault hypothesis concerning the decomposition of molecular radiolysis products in heavy particle tracks, author's efforts were directed toward the quantification of initial radiolysis yields. Special experiments have shown that Gf-ffcO] is much the same from a- and y-radiolysis (around 4.2 molecule/lOOeV). The author had the good luck to discuss her results with Pr. M.Haissinsky from Laboratory Curie.

-222- CZ9827831

ON THE MECHANISM OF HYDRATED ELECTRONS REGENERATION IN ALKALI AQUEOUS SOLUTION AFTER IRRADIATION BY LIGHT (WAVE LENGTH >700nm)

V.K.Mukhomorov Agrophysical Institute, St.Petersburg, 195220, Russia

It has been experimentally established that on photoexcitation of hydrogen-saturated alkali solution by light in the UV region of the spectrum, hydrated electrons were formed. As one would expect, disappearance of hydrated electrons occurred according to a second-order law. We was supposed that the regeneration of the hydrated electrons is due to the optical excited of two-electron bound dimers with the next decay its on two hydrated electrons. On of the objectives of the present investigation was calculation of the electron excited states of the two-electron dimers. In the framework of continual approximation of the adiabatic and strong coupling limit a scheme was developed for calculations of the ground state and the optical excitation spectrum of the bound state of two-electron dimer. The process leading to decay may consist of different steps and takes a number of alternative courses. It is shown that probability are next transitions: sigma singlet state to sigma singlet state (wave length 905nm) and sigma singlet state to pi singlet state (wave length 877nm). In the first case the decay is going from intermediate triplet term. In the second case pi term is repulsive in all inter electron distances. We have studied both the ways that are considered to lead to the disruption of dimers. Both possibility supplement each other. This mechanism is real the conversion of two- electron dimers into two hydrated electrons. The experimental data agree with these theoretical results

-223- CZ9827832

HIGH ENERGY ELECTRON BEAM INACTIVATION OF LACTATE DEHYDROGENASE SUSPENDED IN DIFFERENT AQUEOUS MEDIA

A. Hategan1, D. Hategan2, V.V. Morariu3, C. Oproiu1, A. Popescu1 1-Institute of Atomic Physics, Bucharest, Romania 2-Institute of Neurology and Psychiatry, Bucharest, Romania 3- Institute oflsotopic and Molecular Technology, Cluj-Napoca, Romania

The direct and indirect effects of 5 MeV electron beam irradiation at various low temperatures, as well as the influence of the presence or absence of deuterium ions in the suspending medium of the enzyme, on the global enzymatic activity of lactate dehidrogenase have been studied. Frozen lactate dehidrogenase suspensions at 0°C, -3° C and -196° C temperatures have been irradiated with the 5 MeV electron beam of a linear accelerator in the dose range 0-400 Gy. Liquid lactate dehidrogenase suspensions in D2O (99.98 %) and ultrapure water (17 ppm) at 0 ° C have been irradiated in the dose range 0-15 Gy. The dose accumulated by the samples was estimated using Fricke dosimetry in calibrating the dosimetric monitor of the linear accelerator. The enzymatic activity of lactate dehidrogenase was determined by measuring the rate of extinction decrease at 340 nm of NADH accompanied by the reduction of pyruvate to lactate. Our experimental results showed an exponential decrease in the enzymatic activity of irradiated lactate dehydrogenase, at all irradiation temperatures. The drastic decrease in the activity for the enzyme irradiated at 0° C (total inhibition for a final dose of 100 Gy) indicate that at this temperature the indirect effects of radiation (due to the water radicals induced by radiation in the samples) are predominant. At -3° C irradiation temperature the indirect effects of radiation are smaller.but still present (a total decrease in the enzymatic activity for a dose of 250 Gy), while at -196° C they are orders of magnitude reduced and the decrease in the enzymatic activity is due almost to the direct interaction of electrons with the macromolecules (70 % for a dose of 400 Gy). The temperature gradient used to lower the temperature of the samples to -196° C influences the results, a two steps technique (-5° C, -196° C) used to obtain the desired irradiation temperature of -196° C, being more appropriate because of the smaller enzymatic activity loss during freezing. The system studied is very complex because of the superposition of freeze-thaw procedure effects on the irradiation effects, both molecular mechanisms being incompletely clarified yet. The data obtained here inform on the high energy electrons influence on the enzymatic activity loss during thawing, when the subsequent growth of the water crystals influences the three dimensional structure of the enzyme. Further studies will be done in order to get more information on the frozen enzyme behaviour under high energy electron irradiation. The presence of deuterium ions in the suspending medium of the enzyme seem to protect the enzyme to the efect of radiation. A 99.98 % concentration of D2O in the suspension medium decreases the global enzymatic activity, but reduces the rate of radiation inactivation of the enzyme. The enzyme suspended in ultrapure water behaves similar as suspended in bidistiled water, in the limit of experimental errors. The study will be continued in order to determine the critical concentration of deuterium ions in the suspending medium which starts to influence the radiation inactivation decrease of enzymatic activity.

-224- CZ9827833

IRRADIATION EFFECTS ON POLYDICYCLOPENTADIENE

M.I.Chipara, C.Oproiu", M.Dimonie2', R-Minea1', M.Badea", M.Vasile3', M.D.Chipara4», C.Mateescu, G.Brates2), B.Negreanu, A.Tirlea1», C.Secu 'National Institute of Materials Physics, Magurele, Bucharest, POBOXMG-7, R-76900, ROMANIA ''National Research and Development Institute for Plasma, Lasers and Radiation Physics, Magurele, Bucharest, POBOXMG-6, R-76900, ROMANIA 2>Institute for Chemical Researches, 214, Splaiul Independentei Avenue, Bucharest, ROMANIA 3>'Faculty ofPhysics, University of Bucharest, Magurele, POBOXMG-il, R-76900, ROMANIA 4)Institute for Electrotechnical Researches, Splaiul Unirii A v. , Bucharest, ROMANIA

Beams of accelerated electrons, incident on polymeric targets induce various physical and chemical modifications [1,2]. In some cases these changes limit the lifetime of polymers subjected to ionising radiation's whereas in certain circumstances, these modifications are used to monitor the irradiation level or to obtain new materials, with improved physical and chemical performances. Studies of the physical and chemical modifications induced in soluble polydicyclopentadiene irradiated with accelerated electrons, using various methods as Electron Spin Resonance (ESR), IR and UV-VIS spectroscopy, thermal analysis, mechanical tests (elongation at break and tensile strength), viscosity and DC electrical conductivity, are reported. The irradiation has been earned out in air, at room temperature at different integral doses (of about 10 MRads). The electron spin resonance investigations have been performed using a JES-ME-3X spectrometer, operating in X band (9 GHz), equipped with a JES-VT-3X, variable temperature accessory. The resonance spectrum of polydicyclopentadiene is located close to the free electron g value, exhibiting an incompletely resolved hyperfine structure, due to the delocalization of the uncoupled electronic spins over protons. The temperature dependence of ESR spectra in the temperature range -120°C -=-200°C has been investigated. The kinetic of free radicals generation process as well as the decay of free radicals, in air, at room temperature is studied. The data obtained by ESR spectroscopy are supported by additional results obtained using a Carl Zeiss Jena, IR spectrometer. The modifications of the electrical resistance (DC) of polydicyclopentadiene, due to the irradiation with beams of electrons, have been measured at room temperature using a Keihley electrometer. The mechanical features (elongation at break, tensile strength, elastical modulus) have been measured at room temperature using a Monsanto T10 tensometer. The changes in the molecular masses of polydicyclopentadiene are investigated using viscosity and swelling experiments and supported by the modifications of the transition temperatures, as noticed by thermal analysis data obtained on both pristine and irradiated samples.

References

1 O.Sisman, W.Parkinson and C.D.Bopp in "Radiation effects on organic materials", edited by RO.Bolt and J.C.Caroll, Academic Press, New York, 1963 2. K. T. Gillen and R. L. Clough Polymer Degradation and Stability, 24, 137(1989)

-225- Topic 4

IONISING RADIATION IN SCIENCE, TECHNOLOGY, AND MEDICINE

Poster presentations

-227- P4-1

INFLUENCE OF MICROWAVES, HIGH ENERGY ELECTRON BEAM AND GAMMA IRRADIATION ON THE OSMOTIC RESISTANCE OF HUMAN ERYTHROCYTE MEMBRANES

D. Catana1, A. Hategan1, D. Martin1, R. Moraru1, V.V. Morariu2, C. Petruc1 1- Institute of Atomic Physics, Bucharest, Romania 2- Institute o/Isotopic and Molecular Technology, Cluj-Napoca, Romania

The effects of 5 MeV electron irradiation and of gamma irradiation at 0° C as well as the effects of 2.45 GHz microwaves on the osmotic fragility of human erythrocyte membranes are presented. Human erythrocyte suspensions at a cytocrit of 16,66 % were irradiated with the 5 MeV electron beam of a linear accelerator and with gamma radiation from a Co60 source, in the range (0-400 Gy). The dose accumulated by the samples was estimated by Fricke dosimetry. Frozen cryoprotected erythrocyte suspensions at -196 ° C were irradiated with microwaves at various power levels (0 - 700 W) for different periods of time (1 -5 min ). The modifications in the membrane fluidity of the erythrocyte membranes were estimated by measuring the hemolysis induced by radiation in the samples and the hemolysis induced experimentally by osmotic stress on the irradiated erythrocytes Our results showed no hemolysis induced by electron irradiation or gamma radiation at 0° C, in the dose range used, indicating that the membrane modifications due to radiation interaction do not reach a critical point to cause swelling of the cells and consequent lysis. The osmotic stress experiments performed after irradiation gave information on the most resistant erythrocyte population in the samples. The gamma irradiated erythrocytes exhibited a similar behaviour for all irradiation doses. The hemolysis induced by strongest osmotic stress used (0 mM NaCl in the medium) was greater than in the case of the nonirradiated sample, with approximately 15-20 %. The electron irradiated samples showed a hemolysis induced by the strongest osmotic stress with 75-85 % higher than in the control sample. In the case of a certain electron dose (100 Gy), the hemolysis degree was found much smaller than for the control sample (35 % from the control, at the strongest osmotic stress). A similar behaviour of the erythrocytes was found in the case of microwave irradiation of the erythrocytes at -196° C , the sample irradiated for 1 minute showing a hemolysis degree of aproximatively 60 % from the control sample. This improvement in the membrane stability, at a specific irradiation time, which is shown in a smaller degree of hemolysis, might be due to the fluidisation of the membrane, which improves the membrane elastic properties. In the case of microwave irradiation it can be assumed that this effect is due to the non-thermal component of electromagnetic radiation Our experimental data suggest that electron radiation and gamma radiation have different impacts on the erythrocyte membrane fluidity, involving probably the different rate of energy deposition in the samples, and the direct interaction of electrons with the erythrocyte membranes

-228- P4-2

POSSIBLE FRICKE DOSIMETRY AT LOW TEMPERATURE

D. Catana, A. Hategan, V.V. Morariu*, A. Niculescu, C.Oproiu, A.Popescu Institute of Atomic Physics, Bucharest, Romania *- Institute oflsotopic and Molecular Technology. Cluj-Napoca, Romania

The aim of this paper is to inform on the possibility of extending the Fricke dosimetry at subzero temperatures, in order to estimate the dose absorbed by frozen biological samples. The dose absorbed by the biological samples might be preferably estimated with a dosimetnc system the most similar with the biological material, in order to estimate in a realistic manner the energy deposited in the samples by irradiation. From this point of view, Friche dosimetry, being appropriate in estimating the dose obtained in aqueous systems, is also useful for the biological samples, in which water has the greater amount. Fricke dosimetry is based on the radiolitic oxidation of Fe2* in Fe3* and the spectrophotometrically determination of the concentration of Fe3* induced by radiation allows to calculate the dose absorbed in the sample. Frozen samples of Fricke solution at -196° C, and samples of Fricke solution at room temperature were simultaneous irradiated with the 5 MeV electron beam of a linear accelerator Our results showed for the irradiated Fricke solution dose values with one order of magnitude smaller than the real values, obtained from the simultaneous irradiated Fricke solutions at room temperature: for the samples irradiated in the (0-100 Gy) range, the frozen samples showed no detectable response and for the range (100-400 Gy) the response was of (0-20 Gy)The explanation of these results involve the low rate of migration of the water radicals induced by radiation, which are involved in the reaction Fe2* —> Fe3*. The radiochimic rate might be also modified at this low temperature because of the reduced rate of migration of the water radicals induced and their local recombination. More data should and will be collected in order to use the frozen Fricke solutions at -196° C as dosimetric system. The extension of Fricke dosimetry at low temperatures will enlarge the dose range in which is applicable today, the frozen samples being allowed to reach a apparent dose of some hundreds Gy For this extension to be done, the real dose should be estimated with another dosimetric system which to allow the determination of higher real doses, in order to calibrate the frozen Fricke solution values. At the same time, the dependence apparent dose-real dose has to be biunivoque, in order to use the frozen Fncke solution as dosimetric system

-229- P4-3

THE USE OF GAMMA RADIATION IN WASTEWATER TREATMENT

A.M. Dessouki, H.F. Aly and H.H. Sokker National Centre for Radiation Research and Technology P.O. Box 29, Nasr City, Cairo, Egypt, WS1

Ionising radiation proved to be more effective for the treatment of wastewater than ordinary conventional methods. In the present study, a try was made to explain the degradation kinetics due to irradiation of aqueous solutions of some active ingredient pesticides. The following pesticides were studied: Tnazine herbicide Ametryn and carbamate insecticide (Applaud) and two Organochlorine pesticides: Aldrin and Chlorothalonil. Factors affecting the radiolysis of these pesticides such as pesticide concentration, radiation dose, dose rate and pH of the solutions were studied. Ametryn, Applaud, Chlorothalonil and Aldrin insecticides were degraded by y- radiation and for the chlorinated pesticides hydrochloric acid was detected. The pH influence has proved to vary according to the type of the pesticide and little degradation was observed in alkaline medium, while more degradation of the pesticides in the neutral medium was observed dependent on the type of pesticide and on its chemical structure. However, the degradation in the acid medium was even higher. A drop in the pH was observed and may be attributed to the degradation of the pesticide molecules to lower molecular weight compounds, such as organic acids. A combined treatment of gamma irradiation and conventional methods was applied and the effect of different additives such as nitrogen and oxygen showed an enhancement in the degradation process especially when oxygen was added. Experiments on the adsorption of these pesticides on some polymeric materials and on Granular Activated Carbon (GAC), showed that GAC has the highest adsorption capacity. It may be concluded that the radiation degradation followed by adsorption of the toxic pesticide pollutants and their removal from wastewater down to concentrations not exceeding the maximum permissible concentration (MPC), according to international standards, proved to be better than the conventional methods of purification.

-230- P4-4

IVESTIGATION OF FORMATION OF CERIUM (III) AMPICILLIN COMPLEX AND ITS GAMMA RADIOLYSIS

Mohammed M.EI-Dessouky*; Abd-El-Elah A. El-Tawil* Egyptian Armed Forces

Cerium ampicillin complex has been inestigated spectro-photometrically. The effects of pH and molar ratio of ampicillin to cerium (III) on the formation of complex were studied. The stability constants for the formed complex at different pH values, were determined. Results proved the possibility of a new utilization of ampicillin for internal radioactive docontamination of human beings from some radioactive lanthamide elemens like cerium. Gamma radiolysis of cerium (III) - ampicillin complex at doses from 20-100 Gy using 137Cs source at pH 5, 7, and 9 was studied The IR & UV spectra as well as the variations in pH before and after their radiolysis were executed. Results showed that the formed cerium (III) ampicillin complex was more stable against decompostion by gamma radiation than ampicillin only. The mechanism of radiation effect on the complex is discussed.

: Military Technical College, Kobry El-Kobba, Cairo, Egypt

-231- P4-5

EFFECT OF GAMMA RADIATION ON SOME ELEMENTS IN CERTAIN ORGANS OF ALBINO RATS

T. Elnimr, S.M.Abdel-Rahim Radioanalysis Research Laboratory Tanta University, Tanta, Egypt

Energy-dispersive X-ray fluorescence (EDXRF) was used to determine the concentrations of calcium, chlorine, iron, nickel, phosphorus, potassium, selenium, sulphur and zinc in heart, lung, liver, spleen and kidney of adult albino rats two months after they were subject to a single gamma radiation dose from Co-60 at 5 Gy. In female rats potassium levels were significantly higher and the calcium levels significantly lower for the irradiated animals when compared to age-matched non-irradiated controls. Significant differences between irradiated and non-irradiated tissues were observed for other elements although no sex related differences could be found. Tissue damage and disturbances of biological functions were observed as a result of gamma irradiation.

-232- P4-6

ACCELERATED ELECTRON BEAM AND MICROWAVE EFFECTS ON THE HUMAN ERYTHROCYTE MEMBRANES

A. Hategan*, D.Martin*, V.V. Morariu**, A.Popescu*, A.NicuIescu*, C.Oproiu *, A.Margaritescu***, V.Bestea* *NILPRP - Accelerator Laboratory - Bucharest, Romania **Institute oflsotopic and Molecular Technology, Cluj-Napoca, Romania ***ICPE-ELECTROSTATICA, Bucharest, Romania

The aim of this paper is to present some results concerning the effects of the microwave irradiation as well as of the combined, microwave and accelerated electron beam treatment, on the human erythrocyte membranes, at liquid nitrogen temperature. Specially designed microwave applicators were developed to study these effects by using only microwave (CW at 2.45 GHz), at various energy levels (0-700 W) and different irradiation times (0.5 min - 3 min), as well as by simultaneous microwave and accelerated electron beam treatment (6 MeV ,1-10 kGy), or by their successively application. The changes in the properties of erythrocyte membranes following the exposure to radiation were estimated by measuring the hemolysis degree induced in the samples by irradiation. The hemolysis is the process of pore forming in thee erythrocyte membrane as a consequence of water uptake within the cell, which takes place when the osmotic equilibrium at the membrane level is perturbed by external factors. The pores formed alow the release of hemoglobin in the external medium, and the dosage of the hemoglobin released is a measure of the hemolysis process.The microwave irradiated eythrocytes exhibit at certain irradiation times (1-2 min) and microwave power levels (400-500 W), values of very small hemolysis, down to 50% from the control sample hemolysis. Microwave irradiation leads to a specific hemolysis evolution consisting of succeeding minims and maxims in hemolysis degree, while by electron irradiation only, hemolysis degree evolution is almost linear with minimal slope in the dose range used. Simultaneous irradiation of the samples showed the predominant role of the microwave on the hemolysis degree evolution, while the successive irradiation procedure leads to the conclusion that electron irradiation has the predominant contribution . Our experimental data suggest that microwaves and high energy electrons have different impacts on the fluidity of erythrocyte membranes, further studies being necessary in order to elucidate the molecular mechanisms induced at the membrane level.

-233- P4-7

MICROWAVE ENERGY ADDITIONAL USE TO IONIZING RADIATION FOR MICROORGANISMS STERILIZATION

I.Indreias1, D.Martin1, C.Oproiu1, V.Dima2, S.Plamadeala3, S.Marghitu1, M.Toma1, M.Radoiu1, V.Bestea1 ' National Institute for Laser, Plasma and Radiation Physics - Bucharest, Romania 2 "CANTACUZINO " Institute - Dep. of Experimental Pathology and Microbiology - Bucharest, Romania " "PASTEUR " Institute for Veterinary Medicine-Bucharest, Romania

The comparative results obtained by applying ionizing radiation and simultaneous ionizing radiation and microwave to sterilization of some microorganisms such as Escherichia coli, Salmonella spiralis, Klebsiella pneumoniae, klebsiella oxytoca, etc., are presented. The results proved that the microorganisms death rate is much enhance by additional use of microwave energy to ionizing radiation. Death rate enhancement is remarkable only at temperature over the critical value on which microorganisms begin to perish by heat only. For this reason the microwave irradiation parameters were controlled to keep the samples final temperature around this critical temperature. Some scientists have reported [1] that for various microorganisms the death rate is enhanced by microwave irradiation more than conventional heating. Violent motion of dipoles in molecules by microwave field seems to cause this effect which combined with ionizing radiation action could give the enhancement of microorganisms death rate. Simultaneous ionizing radiation and microwave treatment results in the reduction of temperature and time as well as in the decrease of the upper limit of required radiation absorbed dose which ensures a completely sterilization process. In this way, the ionizing radiation costs will decrease and industrial application of low intensity radiation sources will be extended.

References 1 S.Soto, C.Shihata and M.Yazu, in "Fifth Int Conf. on Microwave and High Frequency Heating", Cambridge, England, Sept. 1995, p.H3.3

-234- P4-8

IONIZING RADIATION IN THE POLYELECTROLITES TECHNOLOGY

D.Martin1, M.Dragusin2, M.Radoiu1, C.Oproiu1, R.Moraru2, A.Manea3, I.Indreias1, M.Toma1 ' National Institute for Laser, Plasma and Radiation Physics, Bucharest, Romania 2 National Institute for Physics and Nuclear Engineering, Bucharest, Romania 3 Institute for Food Research, Bucharest, Romania

Gamma ray and accelerated electron beam application in the chemistry of polyelectrolites is presented, such as polymerization of aqueous solution containing appropriate mixture of monomers (acrylamide, acrylic acid and vinyl acetate), initiators, complexmg agents and chain transfer agents. The polyelectrolites technology was first developed on a semi- industrial scale with gamma ray sources and then transferred to the electron beam accelerators built in Romania. The effects of radiation absorbed dose, absorbed dose rate and aqueous solution chemical composition upon polymerization process are discussed. It was proved that the radical reaction mechanism of aqueous solutions containing mixture of certain monomers depends on the total monomer concentration as well as the water presence in the system. The radicals originated from irradiated water have a predominant role on the radicals which come directly from monomer irradiation. The irradiated water radicals presence facilitates the polymerization process and decreases the required radiation absorbed dose which was reduced in the range of 0.3-1 kGy for co-polymers of acrylamide - sodium acrylate and in the range of 3 kGy to 9 kGy for co-polymers of acrylic acid - vinyl acetate. Our interest was focused on the basic characteristic optimization, such as high flocculation capacity (high intrinsic viscosity) and high solubility (high linearity or low values for Haggins constant). The crosslinking effect (bad water solubility) can be controlled by chain transfer agents but they lead to lower values for the intrinsic viscosity and sedimentation velocity. For this reason an original feature is introduced, referred as simultaneous ionizing radiation and microwave treatment. This method gives an intrinsic viscosity increase of two times and a radiation absorbed dose decrease of about two to three times simultaneous with a remarkable improvement of co-polymers linearity. The results obtained by testing our polyelectrolites with waste water from food industry are also given in this paper.

-235- P4-9

THE INFLUENCE OF ACCELERATED ELECTRONS ON ESCHERICHIA COLI ENTHEROBACTERIA CYTOTOXIC ACTIVITY

C.Oproiu, V.Dima1, D.Martin, S.Marghitu, A. Hategan, A.S.Popescu, M.Toma National Institute for Laser, Plasma and Radiation Physics-Bucharest, Romania 1 "Cantacuzino" Institute-Bucharest, Romania

The paper emphasises the accelerated electron beam influence of the cytotoxic capacity of entherotoxin Escherichia coli on "in vitro" cell colonies. The VERO cell colonies and tumoral epithelial cells HeLa"2 were treated with different concentrations of irradiated and natural entherotoxin (1... 1000 mg/ml). The irradiation doses were of 1 to 35 Gy. The accelerated electrons influence was estimated through the effect of different absorbed irradiation doses on the entherotoxin and on the protein synthesis in cell colonies treated with irradiated entherotoxin. The following aspects were emphasised: a) there is a dependence relation between absorbed dose and occurred effects on cytotoxic activity of the entherotoxin under accelerated electrons; b) strong inhibition of protein synthesis is produced in cell colonies treated with large amounts of entherotoxin ; c) the cytotoxic activity of treated entherotoxin with 35 Gy accelerated electrons is fully removed; d) the VERO cells showed a better sensitiveness against natural and irradiated entherotoxin, as compared with tumoral epithelial cells HeLa . The irradiation was carried out with ALIN-10 linear accelerator and the dose measurements were done with calorimetric devices and cellulose triacetate dosimetric films.

-236- P4-10

RADIATION AND CHEMICAL TREATMENT FOR PRESERVATION OF CULTURAL HERITAGE

Corneliu C. Ponta, Rodica Georgescu, loan V. Moise, Iulia I. Georgescu National Institute of R&D for Physics and Nuclear Engineering, Bucharest, ROMANIA

In a world more and more uniform, dominated by economical and commercial activities, cultural heritage is a basic argument for identity of a nation. The preservation of cultural heritage became an important social activity. The main aggressors of museum, archival, library and herbarium collections are insects, fungi and bacteria. There are a few methods to fight against them. The classical method of fumigation with pesticides and other toxic gases is practically abandoned now, because of the ecological consequences and associated costs. In between the alternative methods, radiation treatment is the most promising, even though some inconveniences are noticed. Effectiveness of disinfestation, versatility, favourable costtoenefit ratio of radiation treatment, are shadowed by the concern over the damaging effects on basic substances. Most collection items are made of wood, papers, textiles. Cellulose is the major constituent of them. Irradiating an item, the cellulose molecules undergo scissions. Low molecular cellulose associates reduced mechanical properties. Degradation of cellulose matrix continues after irradiation. Long-life free radicals are responsible for the post-treatment effect. Trapped in crystalline regions, they defuse slowly acting for months after irradiation. This paper proposes a chemical treatment to diminish free radicals' concentration and damaging effects on irradiated cellulose materials. Alcohols with small molecules, in vapour state, are used as radical quenchers. Having an important vapour pressure, the alcohol imbibes the paper in 24 h contact time. Two different procedures are followed, to compare the quenchers' influence during and after irradiation treatment. a) paper desiccation - irradiation - alcohol vapour contact b) paper desiccation - alcohol vapour contact - irradiation Different types of paper, including old time types from XVIII and XIX century, were compared with analytical grade cellulose. ESR was used for identification of free radical concentration. A gamma irradiation facility was used and doses were up to 25 kGy (sterilisation dose). Advantages, disadvantages and limitations of the proposed treatment are considered.

-237- P4-U

STUDY OF CURIUM-244 - SILICON INTERACTION

V.M.Radchenko, A.G.Seleznev, R.R.Droznik, and M.A.Ryabinin SSC RF Research Institute of Atomic Reactors, 433510, Dimitrovgrad-10, Ulyanovsk region, Russia

Microsamples of curium-244 alloys with silicon prepared by high-temperature condensation of metal curium vapour onto flat silicon substrate were studied by X-ray. Four intermetallics lattices (CmSi with orthorhombic structure, Cm2Si3 with hexagonal structure, CmSi2 and CmSii. with tetragonal structure) were observed in the initial X-ray patterns. The reflexes of these mtermetallics are disappeared in 4-8 days sample exposure at room temperature (X-ray amorphization under influence of 244Cm alpha-decay). Both samples were shown to have a compound with primitive cubic lattice (a=9.497 A in initial state) which is supposed to be of S1O2 composition. This lattice is swelling by about 0.8% in the course of half-year sample exposure.

-238- P4-12

IONISING RADIATION FOR STUDYING THE AGE CHANGES OF HUMAN BONE MINERALS

V. Zaichick, A. Dyatlov, A. Morozov Medical Radiological Research Centre, Obninsk 249020, Kaluga Region, Russia

Dual X-ray absorptiotnetry (DXA) provides determination of projection bone mineral density (BMD), i.e. the value is the functions of both bone sizes and mineral concentration at the same time. However, these parameters can differently influence the strengthening bone characteristics. DXA measurements of BMD were used to study 150 healthy men and women, Moscow citizens, aged 15-55. Autopsy bone samples of people aged 15-55, died in accidents, were also collected. Neutron activation analysis (NAA) was used to determine contents of major minerals in compact and trabecular bones of the femur neck. The value found for BMD of the femur neck, spine and whole skeleton is the highest one for men and women aged 21-25 and 31-35 respectively The full-value mineralisation process of male compact and trabecular femur neck becomes complete just before the puberty period (15-20 years old). Concentrations of Ca, P, Mg, and Sr in the compact bone remain constant up to 55 years old while there exists a slight demineralization of trabecular bone typical of the age above 50. The comparison between DXA and NAA results obtained for the male femur neck makes it possible to conclude that at the age below 25 bone sizes are still increasing. In particular, the femur neck becomes thicker. The results of;// vivo and /// vitro morphometry agrees well with such a conclusion.

I Jefft BLANK • •III Topic 5

CHEMISTRY OF ACTINIDE AND TRANS-ACTINIDE ELEMENTS

Verbal presentations

-241- CZ9827834

EXTRACTION OF THE FLUORIDE-, CHLORIDE-, AND BROMIDE COMPLEXES OF THE ELEMENTS Nb, Ta, Pa, AND 105 INTO ALIPHATIC AMINES

J.V. Kratz, W.Paulus, E. Strub, S. Zauner Institut für Kernchemie, Universität Mainz, D-55099 Mainz, Germany W. Brttchle, V. Pershina, M. Schädel, B. Schausten Gesellschaft für Schwerionenforschung, D-64291 Darmstadt, Germany J.L. Adams, K. E. Gregorich, D. C. Hoffman, С. Laue, D.M. Lee, CA. McGrath, D.K. Shaughnessy, D.A. Strellis, E.R. Sylwester Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA

Previous studies of the halide complex formation of element 105 in HC1/HF mixtures and extractions into triisooctyl aminé (TIOA) had been performed with the Automated Rapid Chemistry Apparatus, ARCA II. Element 105 was shown to be sorbed on the column from 12 M HC1/0.02 M HF together with its lighter homologues Nb, Ta and the pseudo-homologue Pa. In elutions with 10 M HC1/0.025 M HF, 4 M HC1 /0.02 M HF, and 0.5 M HCl/0.01 M HF, the extraction sequence Ta>Nb>105>Pa was observed and element 105 behaved very differently from its closest homologue Ta. As it is not possible within reasonable effort to model the many presumably mixed fluoride-chloride complexes involved in these studies, theoretical calculations were performed in the pure chloride system predicting a reversed sequence of extraction. To verify this experimentally, and in order to perform a systematic study of halide complexation of the group 5 elements, new batch extraction experiments for Nb, Ta, and Pa were performed with the quarternary ammonium salt Aliquat 336 in pure HF, HO, and HBr solutions. Based on these results, new Chromatographie column separations were elaborated to study separately the fluoride and chloride complexation of element 105 with ARCA II. In the system Aliquat 336/HF, after feeding of the activity onto the column in 0.5 M HF, element 105 did not elute in 4 M HF (Pa fraction) but showed a higher distribution coefficient close to that of Nb (and Ta). In the system Aliquat 336/HC1, after feeding onto the column in 10 M HCI, element 105 showed a distribution coefficient in 6 M HC1 close to that of Nb establishing an extraction sequence Pa>Nb(105)>Ta which is theoretically predicted by considering the competition between hydrolysis and complex formation.

-242- CZ9827835

GAS PHASE CHEMISTRY OF THE TRANSACTINIDES

A. Tiirler Paul Scherrer Institute, CH-5232 Villigeit FSI, Switzerland

In the past few years the gas phase chemistry of the first three transactinide elements (element 104), (element 105) and (element 106) has been studied experimentally using OLGA, the On-line Gas chemistry Apparatus, developed at Paul Scherrer Institute. In each experiment, the investigated transactinide element was identified by measuring the characteristic decay properties of its isotopes. In the chemistry of Rutherfordium and Dubnium evidence for relativistic effects were found, as predicted previously in theoretical calculations. For the first time, the volatility of Sg oxychlorides in comparison to its lighter homologues W and Mo was measured. Also, the half-lives and SF-branches of the nuclides 265Sg and 266Sg were determined. Finally, prospects for a chemical separation of (element 107) and (108) using gas phase chemistry will be discussed.

-243- CZ9827836

CHEMICAL STATE OF MOLYBDENUM, TUNGSTEN AND ELEMENT 106 IN CHLORINATING GASES

V.Ya.Lebedev, S.N.Timokhin, M.V.Vedeneev, A.B.Yakusbev, I.Zvara Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research 14I9H0 Dubna, Moscow Region, Russia

Earlier [1,2], our group reported first chemical identification of element 106 by thermochromatography (TC) with a carrier gas containing SOC1> and free oxygen. A comparative study of Mo and W isotopes with different half-lives in similar conditions indicated that oxochlondes of Mo and W were involved [3] To better understand the chemical state of element 106, we have continued investigation of the TC behavior of short-lived W isotopes Tungsten activities with half-lives ranging from 5 s to 0.5 h were produced at the 4-m U-400 cyclotron through the reactions 144-147>n*Sm (24Mg, xn)llis"170!74W. A target contained 1.0 mg/cm2 of Sm (as oxide) deposited on a 7-yim Al foil The beam intensity was about 3-1012 pps. Recoils thermahzed in I-l/min argon gas were injected into a quartz TC column, 3.5 mm id, with a maximum temperature of 450 °C at 10 cm from the inlet As a chemical reagent, we used air (0.2 1/min) saturated at room temperature with SOCIi vapors, it was mixed with the argon stream at the mouth of the column Two adsorption zones of W isotopes were generally observed: around 300CC and around 200°C The division of the activities between the zones depends on 7V>; namely, the percentage in 165 the higher temperature peak increases with decreasing rh2 The shortest-lived isotope, W, T\-2= 5 s, is entirely deposited at the higher temperature, while the 30-min "4W is found only in the lower temperature zone. These results give evidence for more than one compound being involved; the less volatile compound relatively slowly reacts to form the more volatile one. From the data we have evaluated 40±15 s as the characteristic time of the chemical transport reaction. All available data corroborate the suggestion that the less volatile oxochlonde.WC^Clx is rapidly formed, to be subsequently relatively slowly converted to the more volatile WOC14 The exothermic reaction WO2CI2 + SOCh = WOC14 + SO2 + 46 kJ is probably responsible for that. Very likely, in the above mentioned conditions, element 106 also forms the dioxodichloride, 249 [106]O2Cl2, as it deposits at ~ 300"C For the s.f. lsotope(s) of element 106 produced in the Cf I8 + O bombardment the extent of the possible conversion into [ 106]OC14 is obviously small

1. S. N.Timokhinetal: Report at NRC3, Vienna, 1992, JRNC Letters 212, 31 (1996). 2. I. Zvara et al.: Report JINR El2-97-102, Dubna, 1997; submitted to Radiochimica Acta. 3. A B. Yakushevetal: JRNC Articles 205, 63 (1996)

-244- CZ9827837

THERMOCHROMATOGRAPHY OF ELEMENTAL EINSTEINIUM

Steffen Taut1, S. HUbener1, B. Eichler2, K. Eberhardt3, N. Trautmann3, J. R. Peterson4 ' Forschwigszenlrum Rossendorf, Germany ' Paul Scherrer Itistitut Villigen, Switzerland 3Institutfur Kernchemie, Universital Mainz 4 University of Tennessee, Knoxville, USA

Topic of the presentation are adsorption studies of einsteinium in the elemental state onto metallic surfaces using thermochromatography. This is an approach to determine basic metallic properties, even if the adsorbate metals are available only in very small amounts, as typically for the heaviest actinides. We have measured the einsteinium adsorption entropy on titanium, niobium, and tantalum using elemental Es-254. The results of these experiments verify the calculations of heavy actinide adsorption enthalpies on titanium, vanadium, niobium, tantalum, and molybdenum from earlier thermochromatographic measurements. Furthermore, they are important for an understanding of the thermochromatographic process of the metallic divalent heavy actinides from einsteinium up to .

-245- CZ9827838

TRACER-SCALE CHEMISTRY OF TRANSITION ELEMENTS IN THE GAS PHASE: THEORETICAL PREREQUISITES AND APPLICATIONS

V.P.Domanov Joint Institute for Nuclear Research, Flerov Laboratory of Nuclear Reactions, Dubna, Moscow reg., 141980, Russia

The observation of the difference between chemical behaviour of micro- and macrocomponents in the gas phase is of obvious theoretical and practical interest. Actual absence of collisions between two atoms or two molecules in tracer-scale chemistry probably brings into existence metastable compounds of transition elements which under certain conditions retain their chemical individualities and can be isolated by using, for example, a thermochromatographic technique. It has been found that the heating of earner-free radioisotopes of platinum metals (1010-1012 atoms) at 500°-700°C in a stream of air or oxygen gave rise to volatile oxides RhO3, IrO3, PtO3 as well as exotic compounds of supposed composition H2Ir04 and FtPtO*. All these oxides and acids do not exist in macroquantities. New oxidation state of plutonium +8 has been discovered. Under the heating of trace quantities of ^Pu and 239Pu in a stream of helium containing oxygen as a reagent, three adsorption zones of plutonium have been found. They were located at 450±25°C, 250±25°C and - 55±15"C. It is shown that the last-mentioned zone is connected with adsorption of octovalent plutonium in the form of PuCV Chemical properties of many transition elements belonging to groups I, III, VI, VII and VIII in different chemical systems were studied. Vapours of S, Se, Te, P, As, Sb or H2S were used as reagents. The products of nuclear reactions Hg+p and Cd+p (660 MeV) were heated at 900°C in a stream of He, containing a gaseous reagent. The formed compounds were adsorbed at certain temperatures in the quartz thermochromatographic column The deposition zones were measured using an a- and y-spectrometer. More than 35 volatile compounds of the studied elements were obtained. Their chemical composition was assumed. Nearly alt of the obtained chaikogenides and actinides have not been observed before in a volatile form Some of them - AgS, OsS and AgS - were produced for the first time. Fields of their application are discussed.

-246- CZ9827839

ACTINIDE COMPLEXATION IN THE PUREX PROCESS

I. May, R.J. Taylor, I.S. Denniss and A.L. Wallwork Research and Technology, BNFL , Seascale, Cumbria, CA20 IPCi, U.K.

In the PUREX process Pu(lV) and U(V1) nitrate complexes are extracted into 30% TBP/OK (30% tributylphosphate in odourless kerosene) as UO2(NO3)2.2TBP and Pu(NO3)4 2TBP The actinides can then be selectively stripped back into dilute nitric acid to yield separate uranium and plutonium products. BNFL are currently developing strategies to improve this process culminating in the development of single cycle flowsheets. Two areas highlighted for further investigation are dibutylphosphate (HDBP) complexation of actinides and improved methods of Np(IV) and Pu(lV) stripping from the U(VI) product stream. Drbutyl phosphate is a degradation product of TBP and is known to complex strongly with actinides increasing their extractability into 30% TBP/OK. Of greater importance is the fact that HDBP also inhibits actimde stripping back into dilute nitric acid. The complexation of U(V1) by HDBP in process conditions has been investigated by 3IP n.m.r and U V /vis spectroscopies and various HDBP-U(VI) complexes synthesised and structurally characterised In conjunction with previously obtained U(VI) distribution data (between 30%TBP/OK solution of HDBP and nitric acid) the behaviour of uranium in the presence of HDBP has now been assessed and the results incorporated into flowsheet models This work has been extended to further transuramc-HDBP complexation studies. In contrast with HDBP, complexation of tetravalent actinides with hydrophilic organic ligands such as acetohydroxamic acid and glycohc acid can prevent extraction into 30% TBP/OK This process can be used to selectively strip Np(IV) and Pu(IV) from a U(VI) product stream Ac(IV) complexation has been followed by near infra-red spectroscopy and selective stripping proven by batch solvent extraction experiments and the determination of distribution coefficients. Again the data has been used to provide accurate flowsheet models.

-247- CZ9827840

TEMPERATURE AND IONIC STRENGTH INFLUENCES ON ACTINIDE(VI)/(V) REDOX POTENTIALS FOR CARBONATE LIMITING COMPLEXES

HeJene Capdevila and Pierre Vitorge CEA Saclay, DCC/DESD/SESD, 91191 Gifxur Yvetle cedex, France helene. [email protected], pierre. [email protected]

For waste disposal or environmental programs, actinide behaviour was studied in our laboratory, especially in two limiting aqueous solutions: acidic and carbonate ones where aqua ions and limiting complexes are formed. Cyclic voltametry technique was first validated with well- known U redox system. SIT was used to account for I influence and this also gave activity coefficient consistent with published data Taylor's series expansions to the second order were used to account for T influence, and this methodology was validated on published mean activity coefficients of typically HC1 and NaCI electrolytes. Redox potentials of actinide couples had previously been measured in non complexing media. The above data treatments give standard values for redox potential E°, for the corresponding entropy AS0, enthalpy AH° and heat capacity ACp° changes, and also for the corresponding excess values (i.e. the variation of these thermodynamic constants with ionic strength). This methodology was here used in carbonate media to measure the potential of the redox 4 5 couple PuO2(CO3)3 '/PuO2(CO3)3 ' from 5 to 70°C and from I = 0.5 to 4.5 M in Na2CO3, NaClO4 media. Experimental details and full results are given for Pu. Only final results are given for Np. Previous and/or published data for U and Am are discussed. E and AS variations with T or I were enough to be measured. The values obtained for the fitted SIT coefficients Ae, and for AS and ACp are similar for U, Np and Pu redox reactions. Using this analogy for Am missing data is discussed. £3^3^ formation constant ratio of the carbonate limiting complexes were deduced from the potential shift from complexing to non complexing media for the Actinide(VI)/Actinide(V) redox couples. P3V(U and Pu) and Ps^fNp) were finally proposed using published Ps^CU and Pu) and p3V(Np). These data were then discussed and compared. For Am, this data treatment was rather used to discuss the Am(V*/Am(V redox potential.

-248- CZ9827841

THE X-RAY EMISSION EFFECTS AS A TOOL TO STUDY THE LIGHT ACTINIDES

L.L.Makarov, Ju.F.Batrakov St. Petersburg Stale University, Faculty of Chemistry, St.Petersburg, Russia

1. The X-ray emission chemical shifts (Ch.S.) appear to be a promising tool for the study of the chemical bonding of a wide range of elements, including the actinides. 2. The first observations of the chemical effects in the emission L X-ray lines of Th, U, and Np . The sign of the Th 5f electron involvement in chemical bonding in the compounds of Th IV. Some evidences of the similarity between the X-ray chemical effects observed for UL- and MoK-lines. 3. The complicated nature of the emission process, the relative importance of different contributions to the transition energies ( relaxation's phenomenon, spin-spin interactions, solid state effects). Their account in the theoretical interpretation of the spectroscopic observations. 4. The comparison of the experimental results with SCF HFD calculations (approximation of the atomic configuration average) may be used to describe the states of the emitting atoms in the compounds of actinides in terms of the partial effective charges (Qsf and Qw ) and may be applied for a search of relativistic effects , especially in U5f± -electron states . 5. It has been shown that U X-ray Ch.S.'s observed in a number of the most intensive L-lines (a2, oci, P2, P4, Yi etc., up to 11 lines altogether) for uranium oxides UOr(r=2 +3) may bring a useful information on the magnetic state of emitting atom, provided that the spin-spin interaction between the spin of the outermost (5f, 6d) electron and the spin of inner electrons involved into the X-ray transition is taken into account in the theoretical treatment 6. The isotope shifts between 235U and 238U were observed for the first time in 11 UL emission lines and interpreted as "Volume Size Effect" on the basis of HFD approximation. A distinct correlation was observed between the experimental data and the theoretical volume effects throughout the all studied U L-lines The estimate for the effective radius of ""U nucleus lead to the value Rclr= 7.376 fm.

-249- CZ9827842

REDOX REACTIONS OF U(IV) AND Pu(IV) WITH H2O2 GENERATED IN NITRIC ACID MEDIA BY POWER ULTRASOUND

Ph. Moisy, L. Venault, S. Nikitenko* and C. Madic CEA-Valrho, DCC'DRRV/SEMP. BP 17], 30207 Bagnols-snr-Ceze Cedex, France *lnstitute of Physical Chemistry, 31 Leninsky Prospect, 1 lr9l5 Moscow, Russia

Power ultrasound causes water molecule dissociation on H° and OH0 radicals due to high local temperatures and pressures generated in the cavitation threshold. In nitric acid media scavenging of OH° radicals with NOi followed by NO30 radicals hydrolysis leads to H2O2 formation. It was shown that H2O2 generated under the effect of ultrasound with the frequency 20 kHz and intensity 1-3 Wcm'2 (Ax atmosphere) oxidizes U(IV) to U(VI) or reduces Pu(IV) to Pu(III) in 1-4 M HNO3 in the presence of antinitrous reagents ( N2H5NO3 or NH2SO3H). The effect of HNO3 concentration and ultrasonic intensity on the kinetics of U(IV) oxidation and Pu(IV) reduction was studied.

-250- CZ9827843

THE REDUCTION OF NEPTUNIUM (VI) BY FORMOHYDROXAMIC ACID

R.J. Taylor, I. May and G.C. Brown Research and Technology, BNFL Sellafield, Seascale, Cumbria, CA20 IPG, U.K.

The applications of formohydroxamic acid (FHA) (HCONHOH) in- an Advanced Purex process for the reprocessing of irradiated nuclear fuel have been reported previously [1,2]. It is especially suited to the separation of Np(IV) from U(VI) by the formation of a hydrophilic complex with Np(IV). U(VI) extraction in to 30% tributyl phosphate is unaffected. However FHA has also been shown to be a very fast reducing agent for Np(VI) (NpC>22*). This paper reports the investigation of the reduction of Np(VI) to Np(V) by near infra red spectrophotometry. Measurements using both an external sample compartment and a dipping optrode (to follow the reaction in-situ) connected to a spectrophotometer by fibre optics, have been used. The timescales of the reduction have been defined under a range of typical Purex Process conditions although the accurate determination of the reaction kinetics was not possible due to the rapidity of the reaction. FHA did not reduce uranium (VI) although the slow reduction of Pu(IV) to Pu(III), probably through the hydrolysis product, hydroxylamine, has been observed. Therefore Np(VI) can be efficiently stripped by reduction to Np(V) by FHA when solvent phase (30% tributyl phosphate in odourless kerosene) solutions of Np(VI) and U(VI) are contacted with nitric acid and FHA. Distribution coefficients for Np are very low and similar to those predicted for Np(V). Spectrophotometric evidence indicated complete reduction. The experimental distribution coefficient for U(VI) is equivalent to the predicted distribution coefficient in the absence of FHA thus proving that the extractability of U(VI) is unaffected. Finally, the separation of Np(VI) and U(VI) has also been studied in a single centrifugal contactor stage to confirm that the reduction, under typical process conditions, is compatible with centrifugal contactors which have very low residence times.

[1] The applications of formo- and aceto- hydroxamic acids in nuclear fuel reprocessing, R.J. Taylor, I. May, A.L. Wallwork, IS. Denniss, N.J. Hill, B Ya Galkin, B.Ya Zilberman and Yu.S. Fedorov, J. Alloys & Compounds, forthcoming. [2] Neptunium(IV) and Uranium(VI) Complexation by Hydroxamic Acids, I May, R J.Taylor, IS. Denniss, G Brown, A.L Wallwork, N.J. Hill, J.M Rawson and R Less, J Alloys & Compounds, forthcoming.

-251- CZ9827844

COMPLEX MOLYBDATES OF U(VI) AND Np(VI)

Fedosseev A., Budantseva N., Bessonov A., Grigoriev M. Institute of Physical Chemistry of RAS, Leninskii pr, 31, Moscow, Russia.

The necessity of a long-term storage of components of the burnt-up nuclear fuel forces to search the compounds of actinides with the certain properties. Rather perspective from this point of view are represented molybdate compounds of actinides, distinguished by relative thermal and chemical stability. Nevertheless, such compounds are investigated very little Double molybdates of uranyl with monovalent cations are known - Na2UO2(MoO4)2 6H2O and K2UC>2(MoO4)2 4H2O [1], and also with divalent cations - M(UO2)3(MoO4)4 8H2O (M = Mg, Zn) [2] Molybdate compounds of transuranium elements are represented only by hydrates of simple molybdates and dimolybdates [3] The development of these researches represents not only practical interest, but 2 also allows to compare behavior of actinides in systems of AnO2 with a molybdate ion It is established by spectrophotometrical method, that the degree of uranyl complexation in acidified water molybdate solutions is great. The solutions have strong luminescence and are metastable. After several days from them the bright yellow crystal product of composition: Na2U02(Mo04)2 4H20 is isolated. With change of conditions, for example, temperature and ratio [Mo]:[H*] from acidified solutions of sodium molybdate only the complex of the specified composition is obtained. Neptunyl forms in water solutions of sodium molybdate 1-2M, probably, several complexes because the isobestic points in spectra of Np(VI) at various concentrations of molybdate are absent. From such solutions in time the dark - marsh crystals of composition: Na2Np02(Mo04)24H20 are isolated. From acidified solutions of sodium molybdate the complexes of other structure are formed With replacement of sodium by cesium the crystals Cs2NpO2(MoO4) 2H2O are formed. The behavior of uranyl and neptunyl differs also in solutions of ammonium paramolybdate: (NH4)2i;O2<]vloO4) 2H2O and (NH4)2NpO2(MoO4)22H2O are formed correspondingly From sodium molybdate solutions at the presence of some organic solvents was isolated mixt-valent complex of composition (V |V Na6[Np 'O2]2[Np "O2](MoO4)sl3H20 The study of thermal and spectral behavior of the synthesized solid complexes also specifies the difference in properties of uranyl and neptunyl in investigated compounds and even in isostructural compounds.

[1] D.Burnel Bull. Soc. Chim France, 1970, Nl 1, P.3781-3786. [2] V V.Tabachenko et al Koordinatsionnaya Khimiya. (in Russian), 1983, V.9, Nil, P 1568-1571. [3] A.M.Fedosseev et al. Radiokhimiya. (in Russian), 1990, V.32, N5, P 14-18

-252- Topic 5

CHEMISTRY OF ACTINIDE AND TRANS-ACTINIDE ELEMENTS

Poster presentations

-253- P5-I

ENTHALPIES OF CRYSTAL LATTICES AND STANDARD ENTHALPIES OF FORMATION OF CRYSTALLINE METAL NITRATES, ACETATES AND HALOACETATES

A.V. Baluev Khlopin Radium Institute, St. Petersburg, Russia

Propeties of coordination compounds, both in the crystalline state and in solution, including extraction behavior, depend on electron-donor properties of anions. This was demonstrated, for example, in [1, 2] for uranyl carboxylates and nitrate. This study is devoted to calculation of the lattice enthalpies and standard enthalpies of formation of metal nitrates, acetates, and haloacetates. It should be noted that the above thermody-namic functions are fundamental, and their importance is not restricted to problems of extraction [3,4]. A method for calculation of the enthalpies of crystal lattices and standard enthalpies of formation of anhydrous metal nitrates and carboxylates is presented. The estimation of DH is based on interpolation of the linear plots of this value vs. the Edwards parameter, which, in turn, is a linear function of the logarithm of the acid dissociation constant. Linearity of the above dependence was previously found experimentally for the corresponding uranyl salts [3, 4]. Previously unknown lattice enthalpies and standard enthalpies of formation of a large set of anhydrous metal nitrates and carboxylates are calculated. Thus, fundamental thermodynamic characteristics for about 100 metal carboxylates and nitrates were obtained. We believe that these data will be useful for studying extraction equilibria and other properties of the above complexes

[1]. Baluev, A V. and Suglobova, I.G., Khimiya urana (Uranium Chemistry), Laskorin.B.N , Ed., Moscow: Nauka, 1981, pp. 105-114. [2], Baluev, A.V., Solvent Extraction, Sekine, T , Ed., Amsterdam: Elsevier, 1992, pp 291-296. [3], Markus, Y., J Inorg. Nucl. Chem. 1975, vol. 37, no. 2, pp. 493-501. [4] Baluev, A.V , Radiokhimiya, 1988, vol. 30, no. 2, pp. 161-171.

-254- P5-2

SOLVENT EXTRACTION OF GROUP 4 a AND 4 b METAL CHELATE COMPLEXES. MODEL EXPERIMENTS FOR CHEMICAL STUDIES ON COORDINATION NUMBER OF ELEMENT 104

A.BHewicz Institute of Nuclear Chemistry and Technology Department of Radiochemistry Dorodna 16, 03-195 Warszawa, Poland

To verify the idea, that the coordination number of element 104 could be influenced by relativistic effects the studies on complexation of possible homologs of element 104 in Group 4 a (Zr4+, Hf4"1", Ti4+) and 4b (Sn4+, Pb4+) by thenoyltnfluoroacetone (TTA) and tropolone (T) were performed. Contrary to monodentate ligands TTA, forms octacoordinate complexes not only with Zr4+ and Hf4+ but also with Ti4+, which are extracted to organic phase. Tropolone forms octacoordinate neutral complexes also with Group 4b metal cations Sn4+ and Pb4+. Since octacoordinate complexes of Ti4+, Sn4+ and with Pb4+ TTA and T are much weaker than the respective complexes of Zr4"1" and Hf*+, extraction of these complexes to organic phase requires higher values of pH. The behaviour of 1044+ in TTA or T extraction experiments should answer the question concerning the similarity of 1044+, in respect to CN to its lighter congeners Zr4"1" and Hf4"1" or Ti4+ and Group 4b elements.

-255- P5-3

STUDY ON THE SEPARATION OF U AND Pu BY NON-REDUCTION PROCESS

Han Bingbin, Wu Qiulin, Zhu Yongjun Institute of Nuclear Energy Technology, Tsinghua University, P.O.Box 1021, Beijing, China, P.R.

The non-reduction separation of U(VI) and Pu(IV) was studied by genetic algorithm calculation. The backscrub and strip stage numbers, loading organic flow rate, aqueous strip solution flow rate and its acidity, and organic backscrub solution (30% TBP/n-dodecane) flow rate were selected as optimum parameters. The Pu content in U products (i.e. 10'7gPu/gU) and U loss percentage in aqueous products (i.e. <5%) were chosen as restraining conditions. A hypothetical organic U-Pu solution from the Purex first cycle co-decontamination process (30%TBP/n-dodecane, U(V1): 90g/l, Pu(IV): 1.0g/l, HNO, 0.1M) was fed to the feed stage. The ambient temperature at 25 "C was assumed for the operation (it can be also considered as an optimum parameter). Results of calculation showed that the concentration profile of U and Pu in both phases opposed each other through strip stage and backscrub stage The maximum concentration of U and Pu in both phases appeared at the feed stage However the acidity in both phases changed slightly. The influences of strip acidity and initial TBP content in both organic streams for U yield in organic phase and Pu yield in aqueous phase opposed each other Backscrub stage number and backscrub organic flow rate effect the U yield in organic phase mainly, in contrast to the influences of strip stage number and strip flow rate However the influence of temperature for U and Pu yield were similar. Low temperature had better separation effect for U and Pu Results of calculation showed that among all considered parameters the loading organic flow rate, aqueous strip solution flow rate and organic backscrub solution flow rate were the more sensitive parameters for U and Pu yield and contents in both phases The Pu percentage content in aqueous phase varied from 1.5% to 74% under the condition of Pu loss percentage in the organic phase less than 0.1%

-256- P5-4

PRECONCENTRATION OF ACTINIDE ELEMENTS FROM SOIL AND LARGE VOLUME WATER SAMPLES USING EXTRACTION CHROMATOGRAPHY

William C. Burnett*, D. Reide Corbett*, Michael Schulz*, E. P. Horwitz*, Renato Chiarizia", Mark Diet/, Anil Thakkar5 Presented by Michaela Langer§§ *Environmental Radioactivity Measurement Facility, Department of Oceanography, Florida State University, Tallahassee, FL 32306-3048, USA "Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA sEichrom Industries Inc., 8205 South Cass Avenue, Darien, IL 60561, USA ssEichrom Europe, 50, rue de Paradis, 75010 Paris, France

To achieve the required low level detection limits for actinide elements in environmental samples it is commonly necessary to analyse large sample volumes which is often difficult due to high salt concentrations. The so called "matrix effect" reduces the retention of the desired elements on extraction chromatographic materials dramatically. The current work presents a method which simplifies the preconcentration of tn-, tetra- and hexavalent actinides and allows a rapid gross alpha determination. Recently a new extraction chromatographic resin based on diphosphonate chemistry was developed jointly by a team from Argonne National Laboratory and the University of Tennessee. The Actinide Resin®, commercially available from Eichrom Industries shows an extremely high affinity for actinides in the tri-, tetra- and hexavalent oxidation states also in the presence of high salt concentrations. Moreover the actinide uptake is relative insensitive to complexmg reagents such as fluorides, oxalates, phosphates and sulphates. This work describes the separation procedure and presents its application to the gross alpha determination in soil and water samples. The results show good recovery and are favourably compared to traditional approaches.

-257- P5-5

GAMMA - RAY SPECTROMETRY IN TRPO PROCESS USED TO TREATMENT SALINE HIGH - LEVEL LIQUID WASTE IN CHINA

Liang Junfu Institute of Nuclear Energy Technology, Tsinghua University, P.O.Box 1021, Beijing, China, P.R.

Partitioning and treatment of high - level liquid waste( HLLW) is an important problem for environmental protection and nuclear safety. TRPO process in China is developed for separation of the long - lived nuclides, such as actinides and wTc, from HLLW. In 1996, a hot test on applying the TRPO process to treat genuine highly saline HLLW was carried out in China. The activities of the y nuclides: 137Cs, I34Cs,241Am,144Ce,155Eu,l010 miniature centrifugal extractors were sampled and analyzed. Satisfactory result have been obtained Ge-Li y spectrometer (ORTEC, U.S.A.) was operated on the conditions: HV +3500V, shaping time 0.8x0.8us, amplifier 16x0.00 except for 241Am 32x0.00, 8192 channels, lived time. Determination efficiency is got by deterring standard solution of 137Cs,152Eu, 60Co and 241Am. 1.00 ml standard solution was put into a polyethylene bottle( ID 10mm) and the bottle lwas layed accurately on 2cm right on top of the detector. In range 100 - 1000 Rev, logarithmic relation of efficiency-energy is a good straight line. Log r|=-0.8077 Log E+o 62062 Following results were obtained by y - spectrometry analysis: I 30% TRPO - kerosene has a good extractability to actinide and lanthanide. After 12 extraction stages, more than 99.8% Am and more than 99 0% Ce - Eu are extracted into organic phase. 99.8% Am, Ce and 99.6%Eu in the the organic phase are striped by 5 stages of 5.5 mol/l HNO3, 0.36% Eu m the organic phase is striped by 4 stages of 0.6 mol/1 H2C2O4 .but Am and Ce contents are lower than determination limit. There are not Am, Ce and Eu in 5% Na>CO.i strip solution and in the organic phase after striping. 2.The order of distribution coefficients of actinide and lanthanide in 30% TRPO - kerosene- HNO.; system is Di;u>DAm>D« . In the extraction section, extraction stages for 99% extraction of Ce, Am and Eu are 6, 8 and 10 stages respectively. Extractibility of Am is between Ce and Eu and similar to Nd. This is in correspondence with its ion radius. 3. 30% TRPO - kerosene extracts a part of Ru 38 7% Ru is extracted into the organic phase after 12 extraction stages However, strip of Ru is difficult, 25.5%, 6.8%., 2.9% of total Ru is striped by 5.5mol/l HNO,, 0.6mol/l H2C2O4 or 5% Na2COv respectively 3 5% of total Ru is still lett in the organic phase on the end of all stripping sections.

-258- P5-6

SOLVENT EXTRACTION CHEMISTRY OF ACTINIUM IN ACIDIC ORGANOPHOSPHOROUS EXTRACTANTS - ACID SYSTEM

Liang Junfu, Zhuang Yongneng, Xu Jingming, Zhu Yongjun Institute of Nuclear Energy Technology, Tsinghua University, P.O.Box 1021, Beijing, China, P.R.

Actinium is the first element of the actinide series. It is a high poison element Some extraction properties of Ac have been studied using 228Ac as tracer Three extractants, HDEHP, HEHEHP and HMAHP have been chosen. Structural formula of HMAHP is given as follows: c 11 >-<-<- H-O ->p \, „

(' H i

Where R is mixture of C0-C8 alkyls Before use, all three extractants were purified by crystallization via their copper salts. Their purity was over 99%. Extraction reaction was studied by the slope method. Half extraction pH values of Ac in 30% extractant-kerosene-HNOs are 0.76 for HDEHP, 0.93 for HMAHP and 1.51 for HEHEHP In pH range, plots of log D—pH and log D~log[(HA)2] are good straight line. The slope of the lines is near 3.0, so the extraction reaction can be expressed as follows: Ac"+3(HA)2= Ac(HA2)3 + 3 H* Appearance equilibrium constants of the reaction in HNCK are: K= 6.Ox 10'3 for HDEHP, K= 1 Ox 10"3 for HMAHP and K=2.5x 104 for HEHEHP. Obviously, extractability of the extractants to Ac is: HDEHP> HMAHP> HEHEHP, corresponding well with the acidity of the extractants.

In other acidic system, change relations of the distribution coefficient are: DAC-HCKM >DAl>fri> D,V;.HN()3> DAC-H2SO4 This is in correspondence with applied force between Ac-anion. The influence of various diluentes was also examined. In nonpolar diluents, changes of D are: n-Heptane>n-OdecanesKerosene>Cyclohexane>Carbon tetrachloride In polar diluentes the changes of D values are: n-Butyl ether> 0-Xylene> Xylene> Chloroform. It is obvious that D values of Ac increase with decrease of the solubility parameter 5 of the diluent. Thermodynamic constants of the extraction reaction in kerosene diluent - HNO.i system are given as following : m = -18.78 KJ/mol HJ = 17.06 KJ/mol 4S=-103 J/mol.K for HMAHP tfi= 3.895 KJ/mol 43= 20.549 KJ/mol 4S=-56 J/mol.K for HEHEHP Based on the above study, an industrial experiment of removal of 227Ac and its daughter nuclides from LaiOj by 30% HEHEHP—kerosene had been carried out Obtained results in this system were satisfactory.

-259- P5-7

AQUO ION STOICHIOMETRIES OF RADIUM(II), ACTINIDES(II) AND OF SOME SIMILAR CATIONS

T.Mioduski Institute of Nuclear Chemistry and Technology, Department of Radiochemistry, ul.Doroctnalfi, 03-195 Warsaw, Poland

Solubilities of some divalent lanthanide and actinide sulfates were evaluated and compared with the solubilities of alkaline earth sulfates as a function of a reciprocal effective cationic radius It has been concluded that the shift of the solubilities of LnSO4 and AnSO4 from the CaSO4 - SrSO4 range towards the solubility of BaSO4 and RaSOi is a consequence of differences in the aquo ion structure between [Ln(OH )2 ] , [An(OH )2 ] , [Ba(OH )2 ] and [Ra(OH )2 ] vs. [Sr(OH )2] and [Ca(OH )2 ] This difference in the primary hydration number throws light on a nomadic behavior of Eu(II) (and that of Es(II) and other An(II) and of Yb(II) and other Ln(II) species) which, depending on the system, migrates from Ca(II) to Ba(II) on plots of the Gibbs free energies of solution and complexation. The coordination number (CN) higher by I in the Eu species in respect to the Sr species, in spite of almost the same crystal radii of the Eu and Sr ions at the same CN, is supported by the solution enthalpy and entropy values of the respective sulfates In particular, this difference in the primary hydration explains why, in spite of almost the same crystal cell parameters, the solubility product of EuSO4 is about one hundred times lower than that of SrSO4 and close to BaSO4 while the stability of the Eu(II) complexes of EDTA, DCTA, 2-picolinate, tetraphenylborate, dipirydyl and o-phenantrolme is close to that for the respective Ca complexes. The standard Gibbs hydration energy for the Eu ion must be less exothermic than for the Sr ion by several kJ/mol due to its larger radius in the aquo ion at CN=9 than that of Sr in the aquo ion at CN=8. The primary hydration numbers of 9 and 8 are discussed in terms the rules of 18- and 16-electrons.

-260- P5-8

4+ 16 COORDINATION OF U IN U(P2W17O61)2 " ANION

Ph. Moisy1, L. Bion2, F. Vaufrey3, S. Méot-Reymond4, E. Simoni5 and С Madie1 1 CEA, Valrhô, DCCDRRVSEMP, BP 171, 3021Г BagnoIx-x-Cèx, France 2 CEA, Saclay, DCC DESDSESD, 91191 Gif-s-Yvelte, France 3 CEA, DSVDRM/SHFJ, 4 pi. du Gai. Ledere, 91406 Orsay Cedex, France 4 CEA, DAMDEmPAEP, BP 12, 91680 Bruyères le Châle!, France Université de Paris X!, IPN Radiochimie, Bât. 100, 91406 Orsay Cedex. France

This work forms part of a series of studies concerning the use of heteropolyanions (HPA), such as PiWnOöi'"', for actimdes (IV) stabilization in aqueous solution by selective complexation [I - 3]. The peculiar spectroscopic and magnetic properties of UIV compounds lead us to choose U'^PaWnOöih'6" as a representative anion for the study of the coordination of tetravalent actimdes in HPA complexes 2 "P NMR study in solution on M(P2W'nO«/" (M= Zn" and UO2 ) and M(P2W|7O(,1)2"'" (M=Ce4\ Th4* and U4') complexes enabled us to characterize the tetradendate complexation site of the HPA ligand. The "P NMR chemical shifts of U^WnOcb"" confirm the hypothesis of an U47W°* charge transfer through the U-O-W bonds, observed in the visible absorption spectrum of the complex [1,2]. |A1I 31P 6 NMR recorded spectra of M(P2Wi706i)2' ' complexes are in agreement with the presence of a symmetry plane passing through the central M4' ion.

The second part of this work consists in the preparation and the study of U(P2WnO60:>"" in solid state The synthesised Kio[U(P2W|706i)2].38H20 compound shows visible and near-IR absorption bands identical to those of the corresponding complex in solution. Magnetic susceptibility measurements show that U4' coordination polyhedron consists in a square antiprism (D4d symmetry) formed by eight from the two HPA ligands. Literature shows that the coordination of U4' in compounds formed with small amons (sulphate, acetate and oxalate) correspond also to a similar square antipnsm polyhedron [4-6] As in these cases the small ligands can take up their most stable positions without steric constraints, this may be can explain the large stability observed for U(HPA)2 complexes formed with very rigid bulky ligands.

[1] L Bion, Thèse, Univ. Pans XI-Orsay, also CEA report R5711 (1995, in French). [2] L. Bion, Ph. Moisy and С Madie, Radiochimica Acta 69, 251 (1995) [3] J M. Adnet, L Donnet, P. Brossard, J. Bourges, International Solvent Extraction Conference, 19-23.03.96, Melbourne, Australia. [4] J . Trzebiatowska, J. Chem. Phys. 60 (1963), 843. [5] J. Hanuza, B.Trzebiatowska, Acta Physica Polomca A45 (1974), 885. [6] С Kiener, G Folcher, P. Rigny, Can. J Chem. 54 (1976, in French), 303

-261- P5-9

HIGHLY-SENSITIVE METHOD OF DETERMINATION OF ACTINIDES IN NATURAL WATERS

Molokanova L.G., Maslov O.D., Tolmachyov S.Y., Dmitriev S.N., Gustova M.V. Joint Institute for Nuclear Research, Flerov Laboratory, Dubna, Moskow reg. 141980 Russia

The actimde danger influences upon human are well-known. Uranium concentrations in water are usually in the range of 10"2 -10 |ig-l"' level. Plutonium concentrations in water are of up to 1.810'lsgl"' in the Atlantic Ocean and 910"13 - 210"12 g-1"1 in the Irish Sea. The present work is devoted to the new highly sensitive method of thorium, uranium, plutonium and neptunium determinations in water samples using the (v,f) reaction. The detection limits are equivalent to 2-10"13g of ^Th, 11013g of a8U, 610"14g of 237Np and 310"!4g of 239Pu. The technique includes a radiochemical separation scheme of the analyzed elements (a combination of co-precipitation and anion-exchange), subsequent y- or n-irradiation of the resultant isolated fraction at the compact electron accelerator microtron MT-25; chemical etching of the lexan detectors; scanning the fission fragment in an optical microscope. 234Th, 237U and 237Pu were used as tracers. The radiochemical analysis of groundwater, water from the Volga river, tap water and snow made it possible to find out that the uranium content was more than ten times greater than that thorium. The concentrations of these elements varied depending upon the place of the sample selections and were 0,08 - 10 ug T' for uranium and 0,01 - 0,25 ugl"' for thorium. The described method has a high sensitivity and great advantages over other methods since in some cases it is possible to carry out a direct analysis of water samples or to use minimum volumes of water for the analysis. Besides, the separation and concentration of elements are carried out by only one to three columns and separation time is minimal.

-262- P5-10

PRODUCTION AND RADIOCHEMICAL ISOLATION OF 236Pu USING 237 THE Np(Y, n) REACTION

A.V. Sabelnikov, S.N. Dmitriev, O.D. Maslov, A.G. Belov Joint Institute for Nuclear Research, Flerov Laboratory of Nuclear Reactions, Dubna, Moscow reg., 141980 Russia

One of the best suited radiotracers which permits the determination of the isotopic ratio 239J40Pu/238Pu, enabling in its turn the identification of the environment contamination source (nuclear tests, nuclear plant accidents, etc.), is 236Pu. ^'Pu must meet stringent purity requirements. In particular, the concentrations of B8Pu and 239>240Pu should not exceed (Bq/Bq^lCrMO"4 and 10"*-10"7, respectively. Existing methods of the 236Pu production which meet these requirements are low-efficient and expensive due to a need for an additional purification followed by mass separation procedures. The research performed in our laboratory indicates that the 237Np (y, n) 23CmNp -» a6Pu reaction is more promising for production of high-purity ^'Pu. This is because in the interaction a7 238 24O of photons with Np there are no open channels resulting in - pu. Under this scenario, the isotopic purity of the ^'Pu preparation is determined only by the radiochemical purity of the initial 237Np. In addition, the fission cross section is comparable with the cross section for the main reaction. As a source of gamma-quanta, the circular electron accelerator microtron MT-25 of the FLNR was used. The concentrations of 238Pu and 239l240Pu in the initial 237Np were 0.7 and 0.06 Bq/mg, respectively. The target contained 10 mg of 237Np and was irradiated during 100 hours with a maximum photon energy of 25 Mev The average electron beam current extracted from the microtron was -20 uA. The irradiated target was ,,cooled" down during one month in order to allow a complete decay of 236mNp and short lived y- and P- emitters The target was subsequently dissolved in 8M HNO3 The nuclear reaction products were separated by means of an anion exchange. The 236Pu solution was examined by a Si(Au) surface-barrier detector (0.7 cm2) with a resolution of 18 keV. The 236Pu yield was estimated to be as much as 50 Bq/uAh. Determination of the B8Pu and ~39Pu concentrations in the 236Pu preparation was carried out after a preliminary separation using the electro-magnetic mass separator of FLNR JINR. The ratio 2MPu/238Pu/2"'9Pu was estimated to be l/7xl0"5/6xl0"<;Bq/Bq. The isotopic purity achieved this way meets the requirements of the majority of radioecological investigations. It can be enhanced by 1 to 2 orders of magnitude by means of additional purification of the target material and by increasing the irradiation time The expenditures for production of 23<;Pu using the 2'7Np (y, n) 2'6n'Np -> 1'6Pu reaction are 10 lower compared with the methods utilizing the "' U (a, 3n) (followed by a mass separation) and ~'!U (d, n) reactions. Therefore we can conclude that the 'l7Np (y, n) reaction is the most optimal one for production of "'r>Pu having the isotopic purity of 10''-10"7 Bq/Bq

-263- P5-11

COMPLEXES OF URANYL AND ORGANIC SUBSTANCES BY MOLECULAR ORBITAL CALCULATION

Shinya Nagasaki, Satoru Tsushima, Satoru Tanaka and Atsuyuki Suzuki Department of Quantum Engineering and Systems Science, School of Engineering, The University of Tokyo, Japan

Due to the complex and heterogeneous nature of humic substances, the determination of the formation constants and molecular structures is relatively difficult and leads to a dispersity of values and information as well as discrepancies between them. Recently, for simulating the functionality of humic acids, simple organic substances have been used as model compounds. Speciation and structure of some complexes have been identified by using spectroscopic methods such as time-dissolved laser induced fluorescence spectroscopy and EXAFS. However, available information has not been fully obtained, and it is desirable to evaluate the speciation and structure theoretically as well as experimentally. Molecular orbital calculation can predict the physico- chemical properties, formation energy and equilibrium structure of a molecule. The predictions are made by theoretical calculations based on quantum mechanics. Recent developments of computer hardwares enable the application of the method to the speciation and structure of heavy metal ions, but few studies on actinides have been performed. In the present work, we estimated the bond structures of complexes of U(VI) with simple organic substances by ab initio and DFT (density functional theory) calculations. For example, we calculated the formation energy of uranyl salicylate as a function of a distance between U(VI) atom and the oxygen atom of COO' functional group, and found that the U-Oe, distance is 2.3 angstrom. This well agrees with the result of EXAFS study, in which the U-Oe, distance is reported to be 2.32 angstrom1'1. We compared the calculated results for another complexes with the experimental results.

[1] MA. Denecke, el al:. EXAFS Studies on Anhydrous Complexes of Uranyl and Orthosubstituted Benzoic Acid, Annual Report 1995, Forschungszentrum Rossendorf e.V.

-264- P5-12

SYNTHESIS AND RESEARCH OF NEW (THORIUM-CONTAINING) ION-EXCHANGING FORMS OF THE ZEOLITES

V.P. Nesterenko Belarusian State Technological University, Republic of Belarus

The synthesis of zeolites with improved properties represents an important problem in connection with the development of industry and increasing demands to these molecular sieves. One of the effective ways in this direction is modifying the zeolites by the method of ion- exchange. Ion-exchanging forms of zeolites with one-, two- and three-valent cations [1] are well- known and find a worldwide industrial application Polyvalent cations present special interest, but the synthesis of zeolites with polyvalent cations by ion-exchange is rather hindered or frequently impossible because of destruction of crystal structure. In this work a number of researches is conducted on development of methods of direct synthesis of new (thorium-containg) ion-exchanging forms of zeolites [2], and new information about thorium ion-exchanging derivatives of all main types of synthetic zeolites of industrial application is given. (Types A, Foshasite - X and Y, Mordenite, Erionite, type L are meant) and such natural zeolites as clinoptilolites of two deposits (Dzegvi and Tedzami - Georgia) and their mam characteristics are given. While developing the techniques of synthesis of thorium-containing ion-exchanging forms of zeolites special researches on choice of optimum conditions of ion-exchange with the purpose of maximum preservation of a crystal structure of a zeolite were conducted. The following main factors were taken into an account: I - influence of preliminary thermal processing of zeolite; 2 - concentration of Th (IV) and nature of anion, associated with the cation in the solution; 3 - solvent; 4 - the temperature of processing and pH of a solution, 5 - correlation of solid and liquid phases and duration of their contact; 6 - degree of washing of ion-exchanging forms from redundant salts; and others Varying the conditions of ion exchange techniques were developed and described synthesis of thorium ion-exchanging derivatives - ThA, ThX, ThY, Th-Mordenite, Th-Erionite, ThL and Th-Clinoptitolite - with a various degree of replacement of exchange cations ( I < 1 ) With the assistance of X-Ray, denvatography and IR-spectroscopy physico-chemical properties of synthesized thorium-containing zeolites were investigated, as well as stability in water solutions of acids and bases in a wide range of temperatures and concentrations, and also duration of endurance in aggressive environment, thermo- and steam stability. It is established that the introduction of Th (IV) by ion-exchange is displayed in a number of effects, which depend on the nature of a cation. It provides the possibility to influence the chemical structure of zeolite and on this ground to change their properties in a given direction

[1] D.W. Breck: Zeolite Molecular Sieves. - New York, John Wiley and Sons (1974) [2] P Nesterenko Method of Zeolites Modification Certificate ' 618924 (1978).

-265- P5-13

SPECIFIC FEATURES OF ELECTRON ABSORPTION SPECTRA OF SOME Np(IV) SOLID COMPOUNDS

I.A. Tcharouchnikova, N.N. Krot Institute of Physical ('hemistty Russian Academy of Sciences, Leninskii prosp. 31, Moscow. 11'915, Russia

As it was shown earlier, the measurements of the electron absorption spectra (EAS) of solid Np(V) compounds allows to obtain rather interesting information on their structure, including the polyhedra types of central atoms and the presence and character of mutual coordination of NpO2' ions Such approach seems to be also useful for the study of Np(IV) compounds, in despite of the fact that tetravalent neptunium, unlike Np(V), is characterized by a large variety of coordination polyhedra with coordination numbers from 6 to 12. Some features of Np(IV) oxygen environments and their reflection in the EAS (Shimadzu UV-3100, 500 - 1050 nm) were studied for a number of'Np(IV) compounds, such as the oxalate Np(C2O4)2 6H2O; decatungstates: Na8[Np(W5Ois)2] 30H2O,

K4Na3H[Np(W5Oi8)2] 16H2O, (3-diketonates: Np(CH,COCHCOCH,)4 (I), Np(C6H5COCHCOC(,Hs)4(II), Np(C6H5COCHCOCH3)4 (III), Np(C<;H5COCHCOCF;.,)4(IV), Np(SC4H.,COCHCOCF.,)4 (V), and sulfates: Np(SO4)24H2O, M,Np(SO4)4 xH2O, M2Np(SO4)3 nH20, (M=Na, K, NH4, Cs). According to the X-ray diffraction data, the coordination number of Np(]V) in these complexes is 8, and the oxygen environments have cubic, square-antiprismatic or dodecahedral shapes with different degrees of distortions It was found that, similar to Np(V) compounds, the characteristic bands of Np(lV) are absent for the centrosymmetnc oxygen coordination (Np(C2O4)26H2O, cube). The EAS of solid compounds with square-antiprismatic coordinations ((3-diketonates 1,11, and V) are similar to each other and differ from the spectra of the compounds, which have dodecahedral metal coordinations ((3-diketonates III and IV) The spectral similarity allowed us to predict the Np(IV) coordinations in some compounds, whose crystal structures are unknown The symmetry of the oxygen environment about the central atom is reflected in the long- wave f - f characteristic bands. The almost ideal square-antiprismatic coordination of a D4J symmetry is charactenzd by a narrow band at 980 nm (decatungstates). The distortion of the square antipnsm shift of this peak to a long-wave region. The greater is the distortion of the ideal structure, the larger is the value of the shift (p-diketonate I, II). Lowering the symmetry to DM for dodecahedron results in a shift of the band to the values above 1000 nm (P- diketonate IV) The specific features of EAS in solid state (NaCl pellets) are discussed in comparison with EAS in solutions (benzene or aqueous). The complete coincidence of the positions of the f - f characteristic bands in the solid- and liquid-state spectra is observed only for decatungstates 6 The large size and the rigidity of the (WsOi8) " anions are responsible for the fact that the oxygen environment in a shape of an almost ideal square antiprism is retained in solutions

This work was supported by the Russian Foundation for Basic Research, project No 95-03-08340.

-266- P5-14

STUDIES ABOUT KINETIC OF Pu(VI) REDUCTION BY H2O2 AND Pu(IV) PEROXIDE FORMATION

C. Maillard CEN Valrho, DCC/DRRV/SPHA/LCA; Bat 166; BPJ71; 30207BAGNOLS/CEZE, FRANCE

Reduction of plutonium (VI) to Pu(IV) with hydrogen peroxide is a step in industrial processes used to purify plutonium nitrate solutions. This operation must be very well controlled, in order to avoid imperatively the formation of the Pu(IV) peroxide green precipitate and to obtain exclusively Pu(IV). This led us to study the acidity, [Pu] and [H2O2] concentrations influences on the precipitate appearance and to perform a Pu(VI) reduction kinetic study on a wide range of acidities ([HNO3] : 0.5 ... 8 M), plutonium concentrations ( [Pu(VI)] : 0.1 ... 0.8 M) and [H2O2]/[Pu(VI)] ratio (from 1 to 8).

Our results show that in the following conditions : [Pu(VI)]=l M, T=35 °C, [H2O2]/[Pu(VI)] = 1.45, Pu(IV) peroxide appears when nitric acidity concentration is lower or equal to 2 M. The lower is the initial concentration of Pu(VI), the narrower is the acidity range corresponding to the peroxide precipitate formation ([Pu(VI)] = 0.01 M / [HN03] < 0.35 M). The weaker is the acidity of the Pu(VI) initial solution, the longer is the life of the precipitate ( [HNO3]: 0.15 M / several hours), [HNO3] : 1M/several ). The kinetic curves show two distinct parts : the first part corresponds to an induction period where Pu(VI) concentration doesn't change. The second part corresponds to a linear decrease of Pu(VI) concentration. An increase of temperature greatly accelerates the Pu(VI) reduction rate, the activation energy of the reaction is estimated at about 89 (* 10) kJ/mole. The Pu(VI) total reduction time decreases when initial concentration of plutonium increases. By increasing nitric acid concentration from 0.5 M to 6 M, the total Pu(VI) reduction time decreases. This time increases when [HN03] varies from 6 to 8 M. The molar ratio H2O2/Pu(VI) has a very little effect on the Pu(VI) reduction rate. For a ratio [H2O2]/[Pu(VI)] varying from 1 to 8, Pu(VI) reduction rates calculated from the linear part of the kinetic curves are almost the same.

-267- Topic 6

SEPARATION METHODS, SPECIATION

Verbal presentations

-269- CZ9827845

ANALYTICAL SEPARATION OF RADIONUCLIDES SPECIES WITH NATURAL POLYELECTROLYTES - PROTEINS AND HUMIC SUBSTANCES

Fedor MacASek Department of Nuclear Chemistry, Faculty of Science Comenius University SK-84215 Bratislava, Slovakia

Proteins and their decomposition products, humic substances, represent a class of natural macromolecular ligands, which occur in physiological fluids, soil, and natural waters. Due to their multifunctional nature, the polyelectrolytes enter equilibria with a whole scale of natural and antropogeneous radionuclides. Separation of mixtures of arising species, without disturbing their native occurrence, is a real challenge for separation chemistry. Inspiration appears from the fields of solvent extraction, ion exchange and membrane techniques for metal and colloids separation, and of course from bioseparation processes as well [1-4]. Separation of radionuclides bound with protein and humic substances in solutions is a very complex task because of molecular and functional heterogeneity of ligands and polydispersity of complexes [5-13]. In present paper, the following problems are analysed: 1. Models of interactions, chemical and sorption equilibria, their parameters and analytical use (saturation curves, concentration dependent distribution, slope analysis) 2. Experimental non-denaturing separation techniques of speciation: - ultrafiltration and microfiltration, - membraneless dialysis, - size exclusion chromatography, and - sorption on alumosilicates.

Certain achievements are illustrated by the results obtained at the Department of Nuclear Chemistry of Comenius University for cesium, strontium, europium and plutonium speciation in raw milk and humic acid solutions.

References 1. G.SCATCHARD, Ann.N.Y.Acad.Sci. 51 (1949) 660. 2. J ASUNJO, (ED.), Separation Processes in Biotechnology, Marcell Dekker, New York 1990. 3. J.KLAS, F.MACASEK, Analyst 119 (1994) 1. 4 F.MACASEK, J.Radioanal.Nucl.Chenv, Articles 208 (1996) 5 5. V.MOULIN, J.TITS, G.OUZOUNIAN, Radiochim Acta 58/59 (1992) 179. 6. G.R.CHOH'IN, N.LABONNH-WAU., J.Radioanal.Nucl.Chem 221 (1997) 67. 7 J.I.KlM, K.R.C/.KKWINSKI, Radiochim.Acta 73 (1996) 5. 8. V.M.SHKINKV, O.M.FKDOROVA, B.YA.SIMVAKOV, J.MATTUSCH, R.WI-NNRICH, M.LOHSK, Anal. Chim.Acta 327 (1996) 167. 9. A.PAULHNOVA, P.RAJI-:C. M.ZI;MI;I;RYOVA, G.SASKGIOVA, V.VISACKY, J.Radioanal. Nucl. Chem , in press (1998) 10. F.MACASHK, J.Radioanal.Nucl.Chem,Articles, 183 (1994) 5. 11. F.MACASKK, P GKRIIART. A.MAI.OVIKOVA, A.CKI.KOVA, J Radioanal.Nucl.Chem..Articles 208(1996) 163. 12 I.SSllABAN, FMACASHK, J.Radioanal.Nucl.Chem., in press(l998). 13 I S.SIIABAN, F.MACASliK, V. MATI-I., this Conference

-270- CZ9827846

SEPARATION OF Am(lll) AND Eu(lll) BY SELECTIVE EXTRACTION WITH N-DONOR EXTRACTANTS1

Zdenek Kolarik and Udo MUllich Forschungszentrum Karlsruhe, Institutflir Nukleare Entsorgungstechnik, P. O. Box 3640, D-76021 Karlsruhe, Germany

Separation of actinides from high-level radioactive wastes, and their subsequent transmutation to short-lived radionudides is expected to facilitate largely the management of radioactive wastes. A partitioning process for the actinide separation is most appropriately based on solvent extrac- tion, and it must include the separation of Am and Cm from fission lanthanides. Selective extrac- tion of the small mass of Am(III) and Cm(III) over the 60 times larger mass of lanthnides(III) is considered the most convenient mode of the operation. The necessary selectivity can be attained in using extractants binding the extracted ions through ,,soft-donor", i. e. nitrogen or sulfur atoms. Results of a study of solvating and, less typically, acidic N-donor extractants are presented in this paper. The aim of the study is to obtain general information about the effect of three important parameters on the efficiency of the transplutonide(III)/lanthanide(III) extraction and separation, namely the configuration of the extractant molecule, the nature of the anion participating in the formation of the extracted complex, and the diluent. Am(III) and Eu(III) are taken as representa- tives of the element groups to be separated. Preferably tridentate complexing agents were studied as solvating extractants (B in formulas), with a molecule consisting of a chain of three heterocyclic rings of aromatic type. In spite of their potentially tridentate character, compounds with a five-membred central ring such as 3,5-di(4-alkyl-2-pyridyI)-l,2,4-triazoles turned out to act as bidentate complexants. Thus, further work was concentrated on compounds with a six-membered central ring, such as 2,6-di(2-triazinyl)-pyridmes and 2,6-di(3-tnazolyl)pyridines carrying substituents at the side rings. In the presence of a source of anions A, they extract Am(IH) and Eu(HI) (M in formulas) in the form of synergistic complexes MA3nB, yielding Am(III)/Eu(llI) separation factors of >10 The solvation number n and the separation factor were measured with inorganic anions like thiocy- anates or nitrates and organic anions like carboxylates. Polar diluents like butanol modified xylene (v/v=3/7), and nonpolar diluents like highly branched dodecane were used as diluents. Some general conclusions on the effect of the molecular structure of solvating N-donor com- plexants on their extractant properties and solubility in organic solvents could be made. For ex- ample, replacement of a 2-pyndyl substituent in the extractant molecule by 6-methyl-2-pyridyl or 2-pyrazmyl ones deteriorates both the extraction and the separation efficiency as well as the or- ganic solubility. To give an example of acidic N-donor extractants, the ability of 3,5-di(4-tert-butyl-2-pyridyl)- 1,2,4-triazole (HX) to release a hydrogen ion from the >NH group in the triazole ring is to be mentioned Am(III) and Eu(III) are then extracted into butanol modified xylene as complexes of the type MXj, and Am(III)/Eu(III) separation factors as high as -70 are attained The MX5 type complexes do not exhibit visible tendency to add neutral solvating molecules S (e g. those of tributyl phosphate) and to form so synergistic complexes of the type MX3nS. The acid behaviour does not appear to be a common ability of triazole derivatives, and was further investigated

1 Work performed within the European Commissions research and development programme on radioactive waste mmiagcmcnl. shared cos! action, contract No. FI4I-CT%-()(1IO

-271- CZ9827847

SEPARATION SCHEME FOR LANTHANIDES AND ACTINIDES BASED ON THE APPLICATION OF THEIR LOWER OXIDATION STATES

S. A. Kulyukhin, N. B. Mikheev, A. N. Kamenskaya, and I. A. Rumer Institute of Physical Chemistry, Russian Academy of Sciences, Moscow. Russia

The separation of lanthanides (Ln) and actinides (An), which are analogous elements possessing similar properties is still an acute problem. Using various oxidation states of the elements has allowed the rate of the separation process to be significantly increased and the degree of the separation of one element from another to be raised. These have been mainly the higher oxidation states of Ln and An, although using their lower oxidation states in separation processes could also be very effective. We have developed new methods of the separation of Ln and An that use their lower oxidation states A study of the cocrystallization of di- and tnvalent f-elements with solid-phase potassium chloride from water-ethanol solutions has shown that, unlike Ln2*, Ln3+, and An3*, divalent actinides cocrystallize with solid-phase KC1. These results have allowed a rapid method to be developed for the separation of transcurium actinides (Fm, Es, and CO from solutions containing Ln2*, Ln3*, and An3* (separation factor 10'-104) The separation time is 3 mm. The presence of Ca and Mg (up to 5 mg/ml) does not prevent the separation process. The reduction of transcurium actinides to the 2+ oxidation state is carried out using Ln2* solutions (Ln = Eu, Yb, and Sm). This method can be used for both the group and individual separation of transcurium elements (No - Cf). The method allows a rapid and effective separation of Es and Cf from irradiated Bk and Cm targets, respectively. The addition of sodium tetraphenylborate (NaBPIu) to aqueous Ln2* solutions increases the half-time of the lanthanide oxidatron more than 50-fold This effect, as shown in further studies, is related to the formation of the outer-sphere complexes [Ln(H2O)n](BPh4)2. Divalent actinides can form analogous complexes. The stability constants of the An2* complexes are higher than those of Ln2* complexes. This allowed us to develop a new method of separation of di- and tnvalent f-elements. The method uses NaBPhj as a stabiliser of Ln2* and An2* in aqueous and aqueous ethanol solutions and Ln(OH>3 as a collector of trivalent f-elements. Ln(OH).j is precipitated with freshly precipitated magnesium hydroxide The method allows a rapid separation of Eu from Gd or Es from Bk. A study of the cocrystallization of di- and trivalent f-elements with the solid phase of the [Sr(18-crown-6)](BPh4)2 complex from aqueous, aqueous ethanol, and ethanol solutions has shown that tnvalent f-elements do not cocrystallize with the solid phase of the complex. This allowed us to develop a new method for a rapid separation of f-elements with a separation factor of 102-103 per separation operation. Using various Ln2* makes it possible to change the potential of the system and, consequently, carry out both group and individual separation of f-elements.

A study of the behaviour of Ln and An during the formation of Gd2Cl3 and Prl2 clusters from halide melts has shown that mixed halide clusters can form only those f-elements that, in the 2+ oxidation state, have an f'd1 electronic configuration. We have suggested a new and original method of separation of f-elements (separation factor higher than 103) that uses the above- mentioned clusters in halide melts. The method can be used for the separation of Pu and Am, Eu and Gd, and Np and Am. This work was supported by the Russian Foundation of Fundamental Research (grant 96-03- 32008).

-272- CZ9827848

A STUDY OF COLLOID ENHANCED ULTRAFILTRATION OF METALS AND RADIONUCLIDES

Alena Paulenova, Pavol Rajec Department of Nuclear Chemistry, Faculty of Natural Sciences, Comenius' University, Slovak Republic

During the past few years considerable efforts have been devoted to studying the potentialities of surfactant-based organised systems for the development of new separation techniques1. The colloidal systems considered include micelles, microemulsions, reversed micelles, vesicles, amphiphilic block copolymers, etc.2 The micellar ultrafiltration technique is the most rapidly developing preconcentration and separation technique and it was successfully used in various systems (with the exception of reversed micelles). The pollutant can dissolve in the hydrophobic core of micelles or it can be electrostatically bound to the micelle surface, and then it can be removed from the aqueous phase using semipermeable membrane filters with sometimes very high efficiency. In the binding of charged species, very important role plays the charge of micelles. The macromolecules of water-soluble polymer form negatively charged particles, anionic micelles. Positively charged metal cations bind to these particles and can be efficiently retained by ultrafiltration membrane3. The ultrafiltration performance of ligand modified micellar extraction of some metals (e.g. Cd2* with 8-hydroxiquinoline, Sr2* with di-2-ethylhexyl-phosphoric acid), where ligand was solubilized in anionic micelles of sodium dodecylsulphate or cationic micelles of cetyltrimetyl- ammonium nitrate was studied. This same ultrafiltration conditions as early4 were used. The pH dependence of metal yields, distribution ratios of metals between bulk liquid phase and pseudo- organic micellar phase showed that solvent extraction and micellar extraction are very similar. The solubilization of lipophilic complexing agent takes place in the hydrophobic core of the micelles, similarly to their solubilization in the organic phase in classical biphasic extraction"1 The solutions of humic acid and of its salts with metals have colloidal character. The complexation properties of humic acid in different conditions (pH, concentration, ionic strength,...) were estimated by ultrafiltration technique with polysulphonate membrane (10000 Da) under 400 kPa pressure. Complexation of some metals with humic acid was studied. At given pH the loading capacities, stability constants and ion-exchange constants of humic acid with some metals (Na, Ca) and radionuclides (Sr,Y) were studied. The results are explained by CNM5 mode] of metal complexation with humic acid. Values of complexation constants a with Aldrich humic acid were determined as well (aSr=3.4 and ac>=2.9 in the presence of 0.001 M Sr or Ca as competition ion at pH 5 and mixed a

References: Surfactant-Based Separation Processes. Surfactant Science Series, vol.33. Scamchom J.F.. Harwell J H- Eds.: Marcel Dekker. New York, 1989 lsmael M. Tondre C, Langmuir 8, 1039 (19922) Jarvincn G.D.: Water-Soluble Chelating Polymers for Removal..., TTP Number AL 16C322 Paulenova A., Rajec P.. Adamcik P. J.Radioanal and Nucl. Chcm.. 1998. vol. 227. No. 2 Paulcnova A.. Rajec P.. JeSkova M.: J.Radioanal. and Nucl Chem., 1998. vol. 227. No 2 Kim J.I. et al: Radiochimica Acta, 62.(1993) 35 Paulenova A . Rajec P.. Zembcryova M . cl al J.Radioanal and Nucl. Chcm.. in press.

-273- CZ9827849

STUDY OF SORPTION AND DIFFUSION PROCESSES IN NATURAL BENTONITES

P. Jurtek1, V. Jedinakova-Krizovsi2, P. Ivanova2, E. Carballal Aguete3 'Nuclear Research Institute, Department of Waste Disposals 250 68 Rez, Czech Republic 1 Institute of Chemical Technology, Department of Analytical Chemistry TechnickdC, 166 28 Praha 6, Czech Republic 3 University of Santiago di Compostela, Spain

Sorption and diffusion processes in natural bentonites as the most important mechanisms controlling the migration of radionuclides in this media have been investigated. The distribution coefficients (Kd) have been determined for IMCs and 85Sr by the batch method. Various factors affecting the Kd value as water-to-bentonite ratio, concentration of the competitive cations (i.e. Ca2>, Mg2\ Na' and K.) in the aqueous phase or bentomte-to-sand ratio in the mixed sorbents have been evaluated and will be discussed. 8S Effective (De) and apparent (D.) diffusion coefficients for Sr in the compacted bentonite have been determined using the through-diffusion and the modified breakthrough methods. Dry bulk density and porosity of the dry bentonite and the water content in the saturated bentonite have been measured as well Distribution coefficients have been calculated from the diffusion data using the dry bulk density and porosity values for given conditions. Calculated distribution coefficients have been compared with those determined by the batch method. This comparison will be discussed.

-274- EFFICIENT REMOVAL OF ZINC AND MERCURY IONS FROM AQUEOUS SOLUTIONS BY HYDROUS CERIC OXIDE - A RADIOTRACER STUDY

Shuddhodan P. Mishra* and Vinod K. Singh Nuclear and Radiochemistry lxiboratory. Department of Chemistry, Bernards Hindu University, Varanasi - 221 005, INDIA

A rapid growth of industries throughout the world has created major problems of water pollution via discharge of heavy metal toxic ions as their presence in concentrations higher than the permissible limit affects the survival and growth of water-dependent plants and animals. Mercury ion in various forms is highly toxic to our environment and although zinc is an essential trace element, it becomes toxic at levels of 100-500 mg/day. In addition zinc-65 and mercury - 203 also belong to the group of fission fragments formed in low yields (65Zn ti.-a = 243.6d, 2("Hg ti i = 47d) and as such their removal from our aquatic system is of prime importance The present work deals with the synthesis of hydrous cenc oxide and its use in the study of the uptake behaviour of zinc and mercury ions from aqueous solutions by applying 'radiotracer technique' The influence of various parameters such as concentration, temperature and pH of adsorptive solution have been examined. It was observed that the amount of zinc and mercury ions adsorbed at equilibrium increases with increase of adsorptive concentration (1.0x10"' to 1 0xl0"2M), temperature (3O3-333K) and pH (ca.3 to 10). The results show that about 94% of zinc and 85% of mercury ions can be efficiently removed from 1.0xl0"'M bulk concentration. A very low value of desorption shows that the process of uptake for Zn(II) and Hg(ll) on hydrous cenc oxide is almost irreversible. The thermodynamic parameters deduced inform us about the endothermic nature with 'ion exchange' type of mechanism. Adsorption of these metal ions in presence of some monovalent and divalent cations, anions and complexing agents is influenced significantly The uptake of Zn(II) and Hg(II) ions was not significantly affected by the exposure of hydrous cenc oxide adsorbent to neutrons and y-radiation from a 11.1 OBq (Ra-Be) neutron source having neutron flux of 3.85x10' n.s"' and associated with a nominal y- dose of ca. 1.72 Gy/h Also, the pre-irradiation of adsorbent with a high dose y- cell (Co-60 source) having an activity of ca 2250 Ci (mean dose rate ca. 4.66 kGy/h) could not affect the uptake of Zn(H) and Hg(II) significantly. The results suggest that hydrous cenc oxide can be used for an efficient removal of zinc and mercury ions from aqueous solutions and thus may find a useful application in the treatment of aqueous wastes.

-275- CZ9827850

THORIUM (IV) ADSORPTION ON Ircilia Muscarum AND ITS SORPTION KINETIC

Mahmoud A. A. Aslani, Sema Akyil Ege University Institute of Nuclear Sciences 35100 Bornova, Yzmir-Turkey

The accumulation of heavy metals and radionuclides, and the adsorption of uranium and thonum for the recovery or removal from aqueous systems using various micro-organisms and biological substances have investigated by several groups of workers. The uranium adsorbing abilities of various biopigments, microaigae and chitin, a most abundant organic resource, and its derivatives were also investigated by numerous workers. Heavy metals, radioactive substances such as actinides, chlorinated organics and other compounds have been analysed in bivalves to monitor contamination impacts on marine environments. Carell et. al. studied the environmental information preserved in the annual increments of mussel shell by means of element analyses and radioactivity by using three nuclear analytical techniques, the proton microprobe (u-PIXE), instrumental neutron activation analysis (INAA), and a-track autoradiography. At this paper, the uptake of thorium from aqueous systems by a marine species which is called Ircinia Muscarum (Schmidt, 1864) has been investigated. The Ircinia Muscarum samples were collected from Kusadasi in Turkey. We studied the continuous adsorption of thorium on Ircinia Muscarum. The experimental study was carried out at the optimum conditions of thorium uptake. For these conditions firstly, the adsorption isotherm was formed. Since, this isotherm follows as non-linear sorption of the Langmuir model, we assumed that this phenomena can be an adsorption system. Then we investigated the thorium adsorption at different time intervals at the temperatures of 24°C, 50°C and 70°C, respectively.

-276- CZ9827851

NIFSIL - A COMPOSITE SORBENT FOR CAESIUM - PROPERTIES AND APPLICATION

P. Rajec, J. Orechovska Department of Nuclear Chemistry, Faculty of Science, Comenius University, 84215 Bratislava, Slovak Republic

Insoluble ferrocyanides of Cu, Co, Ni, Zn are highly selective sorbents for heavy ions, and therefore can be used to separate l37Cs from liquid radioactive wastes.1>2 The potassium- nickel ferrocyanides with different compositions from K4Fe(CN)6 or Na4Fe(CN)6 and Ni(N03)2.6 H20 were prepared: Sl-K2NiFe(CN)6, S2 - KNii,5Fe(CN)6 and S3 - Ni2Fe(CN)6. The sol-gel method was used for the preparation of ferrocyanides embedded in silica-gel matrix and spherical shape sorbents have been obtained with particles (diameter 0.2 -1 mm) suitable for column operations. The compositions of composite sorbent were determined by ICP-AAS (Kontron) from samples dissolved in boiling concentrated sulphuric acid. The ratio ofFe : Ni for Si was 1:1.1, for S2 1:1.46 and for S3 1:1.84. In the case of ferrocyanides in silica-gel Fe.Ni ratios were between 1:1.19 and 1:1.3 except the sample IX, the samples with a spherical shape of granules was the ratio Fe:Ni 2.0:1 for SF1, 1.8:1 for SF2 and 1.5:1 for 5F3. The sorbents were analysed by Mossbauer spectroscopy for the determination of the oxidation state of iron in ferrocyanides. Only in the sample IX the presence of Fe III was found to have been caused by oxidation of Fe II during the preparation of the sample. The exchanger contains various active components for SF1- SF3 9.1- 27 %. The specific surface area was 299 - 244 m2/g in case of prepared composite sorbent with 60% of active component. Ion exchange properties were studied at room temperature by both batch and dynamic methods. Capacity of the sorbents were calculated from sorption isotherms (VIIIA - 0.11 mmol/g, XI - 0.57 mmol/g, SF1-4 0.2-0.4 mmol/g). Caesium is fixed on mixed alkaline- nickel ferrocyanide without structural change. The capacity of Cs retention never reached the theoretic value corresponding to a total release of the monovalent ions of the solid.3 3 High distribution coefficients (KD~ 10* cm /g) determined in batch experiments show that these sorbents have a very high affinity for caesium ions, even in the presence of competing K*, Na* and Ca2* ions. The sorbents have a good chemical stability in a wide pH-range (2-12). The irradiation of sorbents VI and VII with high energy gamma-rays (60Co) of a total dose of 1.105Gy causes no remarkable changes in the sorbent properties (KD, sorption capacity and kinetics, mechanical stability). Sorbents were also tested for 85Sr and 239Pu and the results earned out under dynamic and batch experiments have shown that sorbents are not suitable for removal of these radionuclides. Potassium nickel hexacyanoferrate incorporated in silica-gel matrix could compete with others sorbents based on insoluble hexacyanoferrates, has the advantage of good radiation stability and suitable granulometry. The sorbent was prepared on a pilot scale with a capacity about 1000 kg per year with the prospect that it could be easily upgraded to an industrial scale.

References 1 Lehto J., Haukka S., Harjula R., Blomberg M. : J.Chem Soc Trans.. 3 /1990/ 1007 2 Haas PA : Separation Science and Technology, 28 /1993/ 2479 3. Loos-Neskovic C, FedorofTM., Mechen MO. : The Analyst, 115 /1990/ 981

-277- CZ9827852

ANION-EXCHANGE SEPARATION AND DETERMINATION OF THORIUM AND URANIUM IN ESKISEHIR-BEYLIKAHIR ORE IN TURKEY

Y. Altas, H. Tel and M. Eral Ege University, Institute of Nuclear Sciences, 35100 Bornova-hmir, Turkey

One of the most important thonum deposits of the world is situated in Eski§ehir-Beylikahir region of Turkey. This deposit contains rare-earth elements (REE) and thorium as bastnasite 5 mixed with barite, calcite and fluorite. The amount of ThO2 in the deposits is about 3.84xlO tons with a weighted average concentration of 0.21 %. The REE content of this deposit is 4.0xl06 tons with an average percentage of 2.78. In this study, spectrophotometric methods were studied for the determination of thorium and uranium content in the ore. Taking into consideration of the chemical composition of the ore, especially the elimination of the interfering elements which influence spectrophotometric measurements were investigated. In most of the liquid-liquid extraction systems thorium is co-extracted with uranium and its presence in large amounts like Eskijehir-Beylikahir ore interfere seriously the determination of uranium. For this reason uranium was first quantitatively separated from thorium by means of Dowex 1x8 strongly basic anionic exchanger resin and then determined spectrophotometrically with DBM reagent. Thorium which was adsorbed as an anionic complex on the resin, separated from uranium and others interfering impurities was determined spectrophotometrically by thorin reagent after elution. Thorium and uranium in ore were also determined by gamma spectrometric, XRF and ICP-AES methods and the results were compared with those obtained spectrophotometrically.

-278- SORPTION OF COBALT ON HYDRATED MANGANESE DIOXIDE

A. MotI, F. Sebesta, J. John, I. Kadlecovd Czech Technical University in Prague, Department of Nuclear Chemistry, Bfehova 7, 115 19 Prague I, Czech Republic

The sorption of cobalt from aqueous solutions of Co(NC>3)2 onto hydrated manganese dioxide ion-exchangers was followed. Ion-exchangers were prepared by the reduction of potassium permanganate with either ethanol (sample D) or MnCb solution (sample I). Thermogravimetric (TG), differential thermal (DTA), and chemical analyses of both samples were performed. Considering the content of water determined from TG data and the manganese content found, the following empirical formulas of studied exchangers can be written: 4 MnO2. 5 H2O for sample D, and 10 MnC>2. 3 H2O for sample I. DTA measurements allowed to conclude, that sample D was an a-manganese dioxide. The sample I was determined to be either p- or y-manganese dioxide, or the mixture of both. The determination of specific surface yielded 74.3 and 23.1 nr.g"1 for sample D and I, respectively Using 60Co radiotracer, the influence of pH value on the kinetics of the cobalt sorption and on the distribution coefficients KD(ml.g"') values was followed in static (batch) tests. Concentration of Co(NO3)2 in the used solutions was of constant value 7.7.10'* mol l'. The time needed for the equilibration of reaction mixtures was decreasing with increasing pH and greatly varied from the tenth of seconds to hundreds of minutes KD values for both samples were increasing with pH starting from 1.24.10'ml.g"1 (sample D), and 28.3 ml.g"' (sample I) at pH~ 1. As this increase was much more pronounced for sample I, at pH ~ 4 both exchangers exhibited about the same Ka s 1 value ~ 2.2.10 ml.g" Further, slight decrease in KD values was observed above pH ~4.5. The results gained can be qualitatively explained when anticipating, that both absorbers perform as weakly acidic cation-exchangers in H' cycle By the same technique sorption isotherms at pH = 5 were measured and corresponding sorption capacities q (mmol.g"1) calculated. Thus, q values of 0.68 mmol.g"' and 0.21 mmol.g'1 were found for the exchangers D and I, respectively. A remarkable observation is that the ratio of q values almost exactly equals to the respective ratio of specific surface values. Sorption capacity of sample D was observed to increase with pH value up to 2 69 m mol.g"' at pH = 7. Further, the influence of sodium and calcium ions on KD values for the sorption of cobalt at pH = 5 was followed. The presence of Na' ions up to the concentration of 4.0 mol I"1 did not exhibit any effect on both absorbers Calcium ions were found to decrease KD values on sample I by half of an order of magnitude, when present in concentration from [Ca2] = 2.0.10"3 mol I"' up to [Ca2 ] = 2.3 moll"1 No significant impact of calcium presence on D exchanger was observed, under these conditions Both sorbents were tested for the sorption of cobalt from fresh surface (river) water and drinking (tap) water It was concluded from these experiments, that the studied exchangers are applicable for the concentration of cobalt from natural waters.

-279- CZ9827853

SPECIATION TECHNIQUES IN RADIOECOLOGY

Brit Salbu Laboratory for analytical chemistry. Agricultural University of Norway P.O. Box 5026. N-1432 Aas, Norway

Following release from a nuclear source, radionuclides may be present in different physico- chemical forms varying in size (nominal molecular weight), and charge properties (reactivity). Low molecular weight species (LMW), eg ions, molecules, complexes are believed to be potentially mobile and bioavailable while high molecular weight species (HMW) like colloids and partioles are relatively inert. When radionuclide species enter the environment, transformation processes take place due to interactions with natural components. Mobile low molecular weight species may be irreversibly associated with clay colloids (fixation) or radionuclides associated with «hot» particles may be mobilised due to weathering. Thus, the original distribution of radionuclide species will change with time influencing the mobility and biological uptake of nuclides. Information of radionuclide species, transformation processes and kinetics is therefore essential when radioecological consequences are to be assessed. Speciation refers to the use of different fractionation techniques by which information on radionuclide species can be obtained As the concentration of radionuclides in the environment usually is low, specie-specific techniques are seldom applicable. Techniques fractionating species according to size and charge properties allows, however, information on size classes and reactivity classes to be obtained. Fractionation of radionuchdes should, however, take place;;/ situ, at site or shortly after sampling, as storage may influence the distribution of species. There are some few in situ size fractionation techniques for radionuclides in waters. In sea water large capacity (tangential flow systems) is needed, while hollow fibre systems can often be applied for rivers and lakes. By interphasing chromatographic systems (ion exchange columns) with hollow fibres, in situ sampling, size and charge fractionation can be performed simultaneously. For small volume soil waters in situ suction techniques may suffer from methodological effects. When radioactive particles or colloids are collected, structural information can be attained by using different electron microscopy techniques (TEM, SEM interphased with XRMA). Separation of radionuclide species in solid samples, i.e. soils and sediments is still an analytical challenge Grain size analysis and determination of radionuclides associated with the sand, silt, clay and colloidal fractions should be combined with sensitive surface analytical techniques. However, the term mobility of radionuclides in soils and sediments refers usually to the degree of binding reactivity to natural components Thus, reactivity studies using extraction reagents can be useful for distinguishing between reversible and irreversible (or slow reversible) kinetics processes Repeated extractions with inert electrolytes (or by lowering pH gradually) should reflect if reversible processes (e.g. physical, electrochemical sorption) take place. In contrast, information on irreversible processes (eg chemisorption) is obtained if strong red/ox agents are needed for dissolution of species (binding rupture). The paper will focus on available size or charge fractionation techniques which should be useful within radioecology. Results obtained from research activities at LAK will be used to illustrate the topic in question.

-280- CZ9827854

DETERMINATION AND SPECIATION OF PLUTONIUM, AMERICIUM, URANIUM, THORIUM, POTASSIUM AND 13fCs IN A VENICE CANAL SEDIMENT SAMPLE

Testa Corrado0, Degetto Sandro*, Desideri Donatella0, Guerra Francesca", Meli M. Assunta0, Roselli Carla° General Chemistry Istilute, Urbino University, Urbino, Italy VCTIMA-CNR, Padova, Italy

A sequential extraction method consisting of six operationally-defined fractions has been developed for determining the geochemical partitioning of natural (U, Th, "K) and antropogenic (Pu, Am, 137Cs) radionuclides in a 40-50 cm deep sediment sample collected in a Venice canal. Extraction chromatography with Microthene-TOPO (U, Th), Microthene-TNOA (Pu) and Microthene-HDEHP (Am) colums was used for the chemical separation of a single radionuclide; the final recoveries were calculated by adding 232U, 228Th, 242Pu and 243Am as the yield tracers. After electrodeposition the alpha spectrometry was carried out. I37Cs and 40K were measured by gamma spectrometry. The total concentrations in the wet sample, obtained by a complete disgregation of the matrix 23 24 24l by NaOH fusion, were the following: »* *pu = 610±80 mBq/kg, ^Pu = 13±5mBq/kg, Am = 200± 30 mBq/kg, 137Cs = 6.9 ±1.1 Bq/kg, U = 1.33 ± 0.14 ppm, Th = 2.69 ± 0.26 ppm, K = 0.72± 0 04 %. The mean ratio ^Pu/ 240Pu ( 0.02) shows a contamination due essentially to fall-out and U and Th alpha spectra indicate the natural origin of two elements. The absence of 134Cs in the sample proves that at 40 - 50 cm depth the sediment was not affected by the Chernobyl fall-out. As far as the speciation is concerned the following fractions were considered: water soluble, carbonates, Fe-Mn oxides, organic matter, acid soluble, residue. Pu (-65%) and Am (~ 90%) were present predominantally in the carbonate fraction; U was more distributed and about 30% appeared both in the carbonate fraction and in the residue; the majority of Th was present in the residue (~ 67%); 40K was totally present in the residue; finally ''7Cs was found mostly in the acid soluble fraction (~ 46%) and in the residue (~ 40%). Researches are in progress to determine the concentration of some stable elements (Fe, Mn, Al, Ti, Ca, Pb, Sr) in the different fractions to get more information about the chemical association of the single radionuclides.

-281- CZ9827855

SOLUBILITY AND TRANSPORT MEASUREMENTS AS TOOLS FOR THE SPECIATION OF f-ELEMENTS AT TRACER-SCALE AMOUNTS; APPLICATION TO Eu AND Th IN PHOSPHATE MEDIA

B. Fourest*, P. Tarapdk", R. Trskova"*, F. David", G. Lagarde*, C. Lindecker", J. F. Le Du" * Institut de Physique Nucleaire, 91406 Orsay Cedex, France ** Department of Analytical Chemistry CHTF, Slovak Technical University, Radlinskeho 9, 81237Bratislava, Slovakia *** J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, 18223 Prague, Czech Republic

The spetiation of f-elements in near neutral aqueous solutions simulating natural waters is controlled by their tendency towards hydrolysis and by the presence of strong complexing agents, such as phosphate anions, in the solutions. Thermodynamic data concerning the f- elements/phosphate systems are, however, often based on estimations obtained by analogy and not supported by experimental data. Moreover, the precipitation of the hydroxide and phosphate compounds considerably lowers the element concentration in the solutions under investigation. Only methods relevant of radiochemistry can be used; they are based either on the distribution of a radionuclide of interest between two phases (solubility measurements) or on its moving in solution (capillary diffusion and migration). The two kinds of method have been applied and are compared in the present work. Predictive curves giving the variation of the mobility and the concentration of Europium as a junction of pH (in the range from 2 to 9) and/or phosphate concentration (102 -10'* mol/1) can be proposed from selected literature data. Capillary electrophoresis experiments show that the mobility decrease due to hydrolysis occurs at a pH value lower than expected. The peak intensity is correspondingly smaller, but this observation cannot be simply related to a change in the charge of the migrating species because of sorption and precipitation phenomena on the capillary walls. Diffusion coefficient measurements by the so called "open end capillary" method confirm the formation of larger and/or less charged species starting at a similar pH value. In the presence of phosphate anions, both transport methods should indicate the presence in solution of species having a larger size than expected, which could be polynuclear. Solubility measurements give more information but require the synthesis of a well-defined labelled phosphate compound (namely EUPO4, Th3(PC>4)4 or Th4(PO4>4P2O7). The total concentration of f-elements detected in the solutions equilibrated with these compounds allow to deduce, by making vary only one parameter in the solution (pH or phosphate concentration), the form and the charge of the different species prevailing in the solution. Limitations are also met due to the very weak solubility of the involved compounds. The solubility method appears particularly interesting in the case of concentrated phosphate media (1 0.1 M).

Work supported by the French agency ANDRA

-282- CZ9827856

2+ BEHAVIOUR OF UO2 IN HIGH ACID SOLUTIONS (12 M): CHARACTERIZATION AND COMPLEXATION WITH HPBI

I. Billard1, M. Bouby1, J.P. Brunette2, G.J. Goetz-Grandmonf2,1. Rossini1 ' IReS, CNRS'IN2P3-ULP,Chimie Nucléaire BP2S, 6'OS' Strasbourg Cedex 2, France Laboratoire Je Chimie Minérale et Analytique (CNRS-VLP.UMR r5I2), Ecole Européenne Je Chimie, Polymères, Matériaux, BP296, Strasbourg, France.

This work is aimed at studying the complexation of U(VI) with a synthetic extradant of actinides. A preliminary work consisted m studying the behaviour of UO2" in highly concentrated nitric acid solutions, which are the industrial media of extraction of the actinides from nuclear waste The characterization of uranyl ion was performed through different spectroscopic methods : spectrophotometry and time-resolved laser induced spectrofluorometry The intensities of absorption and emission spectra, and lifetimes of the uranyl ion were measured up to highly concentrated solutions of perchloric and nitric acid (12 M). Perchloric solvent was firstly selected for its non complexmg properties towards UO2" In this frame, the influence of NO*' complexation is discussed in the case of nitric acid. 2 Secondly, the complexation of UO2 * with the extradant was studied. The extradant is a ß- diketone, an organic molecule which has been used extensively for the extraction of various metals. This particular ß-diketone molecule has a heterocyclic ring (isoxazole) as a substituent which increases the effectiveness of the separation of metals and actinides Therefore the complexation of UOi" with HPBI (3-phenyl-4-benzoyl-5-isoxazoIone) has been investigated. A series of experiments was carried out on solutions of HPBI and UOi" in perchloric acid in order to avoid any other complexation, and in nitric acid up to 12 M in order to simulate the industrial conditions which may occur in the waste reprocessing The previously proposed model involving excited species of the uranyl ion (1), already checked up to 6 M, is extended up to 12 M. In addition, the effect of ionic strength is accounted for, using dedicated models of the literature. The determination of the constants of complexation includes ionic strength calculations

(1)M. Arvis, N. Keller, G FolcheretB Hickel, J. Photochem ,21(1983)313

-283- CZ9827857

RADIOTRACER STUDY OF THE STABILITY OF CADMIUM COMPLEXES WITH HUMATES AND THEIR SIZE FRACTIONS

J. Mizera1, P. BeneS1, and E. Sebestova2 'Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, CTU Prague, Bfehovd 7, 115 19 Praha I, Czech Republic 2 Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, VHolesovickdch41, 182 09 Praha 8, Czech Republic

Humic substances (HS), naturally occurring heterogenous organic polyelectrolytes, affect speciation and migration of trace metals and radionuclides in the environment by formation of relatively stable complexes. Humates industrially produced by alkaline leaching of naturally oxidized brown coal, so-called oxyhumolite, have also been considered as a relatively cheap material for heavy metals decontamination by waste water treatment In the presented work, binding of Cd(II) by various HS was studied using a radiotracer version of the free-liquid electrophoresis, with l09Cd as the radiotracer. The method enables to determine the degree of complexation of a metal from a decrease of its effective cathodic mobility observed in the presence of a complexing agent, while an anodic mobility can appear. Ultrafiltration in the radiotracer arrangement and potentiometry with a Cd ion-selective electrode (ISE) were used as complementary methods. Coal sodium humates industrially produced in the Czech Republic, Aldnch sodium humate, and their size fractions prepared by ultrafiltration followed by freeze-drying, were examined. The degree of complexation was evaluated over a wide range of the metal concentration (1010 -10'3 M) with humate concentration 10 mg/1, pH adjusted to 6, and ionic strength fixed at 0.01 M by addition of NaCIO4. A simple discrete ligand model with two types of binding sites (simplified Scatchard model), and a continuous distribution model (Differential Equilibrium Function) were used for analysing the data. Electrophoresis generally yielded somewhat higher values of the degree of complexation compared to ultrafiltration and the ISE potentiometry. The use of the ISE potentiometry was 6 restricted only to the total concentration of Cd added ([Cd]toi) >10" M due to a limited linearity of 6 the calibration curve at [Cd]toi < lO" M. The ultrafiltration results were strongly affected by rather 6 high sorption losses at [Cd][ot < Iff M. Significant differences in complexation behaviour towards Cd were found among humate samples studied. Comparing parameters of the discrete ligand model for the samples examined, complexation ability of humates seems to be governed rather by the capacities of their complexing sites than by the values of the binding constants, which are similar for different samples. However, determination of the parameters was often difficult due to some arbitrariness in locating the two linear parts of the Scatchard titration curve, and a poorer 7 accuracy of low mobilities observed at very low metal loading ([Cd]M < 10' M). Experimental data from electrophoretic experiments can be successfully described by the continuous distribution 4 7 model in the concentration range 10" -10" M of [Cd]M. The more scattered data at lower [Cd]tot could not be curve fitted with a reasonable accuracy. An attempt was made to relate the differences in complexation properties of the HS examined to their composition and structural characteristics given by their chemical and spectral analysis.

-284- CZ9827858

MULTISENSOR SYSTEM FOR DETERMINATION OF IRON(II), IRON(III) AND URANIUM(VI) IN COMPLEX SOLUTIONS

A.V.Legin, B.L.Seleznev, A.M.Rudnitskaya and Yu.G.VIasov Chemistry Department, St.Petersburg University, St.Petersburg, 199034, Russia

The mining and processing of uranium ore has contaminated wide areas in some european countries. For example, forty-five years of uranium mining in the southern parts of the former East Germany resulted in more than 800 mine tailing piles containing 500 millions tons of rock material on the area over 1000 km2. For radiological and environmental assessment and efficient remediation actions it is necessary to control the composition of waters flooding the mines. The redox reactions play the key role in the chemical process in such a systems. The most important redox pairs coupled to each other to a certain degree are U(IV)-U(VI) and Fe(II)-Fe(III)> because different oxidation states of a element are related to different solubility, and consequently, different mobility. Collecting mine water samples and analysing them in a conventional laboratory significantly disturbs the system because of essential oxidation of U(IV) and leads to false analytical results. No methods are currently available for in situ speciation of these redox pairs. One of the possible solutions of the problem is the use of sensor arrays together with pattern recognition math methods (PARCs) for interpretation of their signals. Earlier we developed and applied such a system (the so called "electronic tongue") for determination of ionic components and related chemical forms [1]. A primary part of multisensor systems is a specially designed sensor array. Cross-sensitivity to different components and stable and reproducible responses in complex media are of primary importance for sensors of such array. However, previously there were no attempts to apply multisensor approach for development of sensor systems, capable to determine not only species recognised via ionic processes but also redox potential generating components. The aim of the present paper is the development and analytical evaluation of a multisensor system for determination of low content of iron(II), iron(III) and uranium(VI) in complex aqueous media. Sensor array included sensors on the basis of chalcogenide vitreous materials with redox and ionic cross-sensitivities, crystalline silver sulphide electrode, noble metal electrodes Pt, Au, Ag and redox sensor on the basis of oxide glass. Potenuometric measurements have been taken in a conventional electrochemical cell vs. a standard Ag/AgCI reference electrode. All measurements have been taken at room temperature Calibration solutions contained UO2(NOj)2 in concentration range lO^-l^xlO" mol/L, K5Fe(CN)6 and K4Fe(CN)6 or FeSO4x(NH4)2SO4 and FeCl,, with the ratio of Fe(II)/Fe(IH) concentration from 100:1 to 1:100, the total concentration of Fe was 10"4 and 10'5 mol/L. All solutions have been made on the background electrolyte of calcium and magnesium chlorides and sulphates with the fixed content of 5-27 mmol/Lf of each component which is a typical one for groundwater or mining water. Sensor potentials have been processed by a back-propagation artificial neural net. Average error of determination of Fe(II) and Fe(lll) is about 20 %, of uranium(Vl) - 40 % It was found that sensitivity of the sensor array to iron and uranium is irrespective of the chemical form of these species

Reference. Di Natale C , Davide F., Brunink J.A.J, D'Amico A , Vlasov Yu.G , Legin A V , Rudnitskaya A.M. Sensors and Actuators. 1996, V.34, Nl-3, p.539-542.

-285- CZ9827859

ELECTROCHEMICAL BEHAVIOUR OF TECHNETIUM ON MERCURY ELECTRODE IN ACETATE BUFFER MEDIA.

O. Courson, C. Le Naour, F. David Institut de Physique Nucleaire, 91406 Orsay cedex, France

Technetium, the lightest artificial radioelement, which "Tc isotope is formed in high yield by fission of ^U, is one of the fission product which is important in the nuclear waste management. The rich and complex solution chemistry leads up to now to an insufficient knowledge of its behaviour in PUREX process and in the environment. In order to understand the reduction mechanism of pertechnetate on mercury electrode, we have developed electrochemical techniques which use an additional time parameter to classical techniques used on mercury electrode. On microelectrode, we have observed, for long time measurements (polarography 3D), a transformation of the first polarographic wave into two waves, which characterizes the reduction of Tc(VII) in Tc(III), as well as a modification of the catalytic peak associated with technetium metal formation. Moreover, differential capacitance determination of electrode/solution interface brings to the fore the existence of species (Tc(IV), Tc(0)) on mercury in reduction zone corresponding to the following reductions : Tc(VII)-> Tc(III) and Tc(III)-> Tc(0). Moreover, the Tc(III)-Tc(O) reduction brings intermediates Tc(I) and Tc(II) which is present only for faster the scan rate. Results obtained on microelectrodes have been confirmed on macroelectrode : the insoluble species Tc(IV) and Tc are formed during the reduction of Tc(VII) on metal. Thus, in acetate buffer media (pH 4.6), the pertechnetate reduction is characterized by the presence of adsorbables species (TcC>2 hydrated, Tc). Moreover, the different electrochemical responses obtained with our techniques like polarography 3D (waves and catalytics peaks) can be allocated to the following stepwise : Tc(VII) -> Tc(V), Tc(IV) ->• Tc(III), Tc(III) -> Tc(I) et Tc(I) -> Tc(0). The Tc(V) formation is followed by the rapid disproportionation of Tc(V) and Tc(VI) and the Tc(I) reduction is associated with the protons reduction.

-286- C29827860

INFLUENCE OF TECHNETIUM AND RHENIUM SPECIATION ON THEIR SORPTION ON NATURAL SORBENTS

M. Kohltfkovii, V. Jedinikovi-Kffiova, M. HorejS Department of Analytical Chemistry, Institute of Chemical Technology, Technickd 5, CZ-166 28 Prague 6, Czech Republic

Natural sorbents are mostly useful for retardation of the radionuclides. In this case, the possibility of using of the natural sorbents as a carrier materials for the radiopharmaceutical in vitro applications has been tested. The sorption experiments with technetium-99 have been earned out on bentomte R. The IQ values have been determined by the batch method. The results of the comparative study of the determination of the distribution coefficient using radiometric and polarographic methods are discussed from point of view of sorbed radionuclides speciation. The DPP polarographic reduction of ammonium pertechnetate and potassium perrhenate has been studied in the aqueous solution with a variety of supporting electrolytes. The formation of the rhenium and technetium complexes as a function of the aqueous phase pH has been investigated by the polarographic and electrophoretic methods.

-287- CZ9827861

RADIOCHEMICAL TRACE AND SPECIES ANALYSIS IN NUCLEAR SAFETY RESEARCH

Horst Bruchertseifer Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

Safety and accident research programmes are important and indispensable in connection with the operation, improvement and future design of nuclear reactors. Recently the activities of the nuclear reactor research are concentrated mainly in two directions: • the test and study of reactor structural material of nuclear power plants in operation, especially concerning the extension of their operational lives and • the investigation of the fuel and fission product behaviour in the case of severe reactor accident. In both areas of research, radiochemistry plays an important role, sometimes invaluable. That is especially true in the case of material analysis, experiments under near-realistic conditions using radioactive tracer and in the interpretation of the interactions of elements and their species In some selected examples the relevance of current radiochemical safety research is demonstrated. The material of the structural components in the core of a power reactor undergo changes in their microstructure and chemical composition, causing embrittlement, lost of mechanical stability and integrity. To determine the irradiation effect on the stability of reactor structural components, it is necessary to measure their mechanical material properties and to know their dependence from the fast neutron fluence. Using a new method of radiochemical analysis, developed in our institute, is it now possible to measure precisely and very sensitively the fluence of reactor steel after a long-term irradiation. The nuclide 93mNb was synthesised in neutron reactions with natural niobium, which is an alloying addition of steel. It was chemically isolated and its specific activity was determined by total reflection X-ray fluorescence analysis and y -spectrometry. In a second fraction, pure iron, the nuclides 55Fe and '"Fe were determined. The separations were performed by remotely-handled middle-pressure chromatography in a hot-cell. The main element of interest in the released fission product (FP) mixture in an severe accident is undoubtedly the volatile iodine. The analysis and investigation of their behaviour in core melt experiments takes a central part of the international PHEBUS FP Severe Accident Experimental Programme. The first research results are reported and the necessity and the possibilities of species analysis are discussed

-288- Topic 6

SEPARATION METHODS, SPECIATION

Poster presentations

-289- P6-1

COMPOSITE ION EXCHANGERS: SORPTION CHARACTERISTICS OF URANIUM AND THORIUM IN SULPHATE, NITRATE AND CARBONATE MEDIA

Sema Akyil, Meral Eral, Mahmoud A. A. Aslani Ege University Institute of Nuclear Sciences 35100 Bornova-lzmir, TURKEY

The composite ion exchangers are a special class of adsorbents developed to improve the processes of separation, concentration or removal of metal ions from solutions. In this study, the applications of prepared composite ion exchangers with a new and rapid method are investigated Synthetic and natural zeolites were used as the active components for preparation of the composite ion exchangers as zeolite-X and clinoptilohte. The products were characterised further by XRD. The sorption behaviour of uranium and thorium from aqueous systems on composite ion exchangers have been studied by a batch technique. The uranium and thorium uptake capacity of prepared composite ion exchangers were investigated. Uranium and thorium in solution were determined spectrophotometrically by Arsenazo III. Adsorption yield (%) were calculated for some ions where are presented in 4 different solutions. These ions were measured by using atomic absorption spectrometer. The sorbents were successfully tested for removal of uranium and thorium from acidic and alkaline leach solutions containing uranium and thorium. The composite-X and composite-C, which are having synthetic zeolite-X and natural zeolite clinoptilohte, have proved to be effective adsorbents for uranium and thorium, respectively. The uranium uptake on composite-X was decreased with decreasing pH. It was found that, the uptake of Mg+2, Al+3, Si+4, Na+, Ba+2 and Ca+2 on composite-X were negligible. However, uptake of K+ was taken into consideration. It was observed that the uranium uptake was increased with decreasing amount of uranium in solution. It was seem that composite-C was approved to removal of uranium from alkaline solutions. Uptake of Fe+3, Mg+2, Al+3, Si+4, K+, Ca+2, Ba+2 on composite-C were negligible. The thorium uptake on composite-C was higher than composite- X. It was observed that the uptake of Fe+', Mg+2, Al+3, K+, Ca+2, Ba+2 in both of composites were competed with thorium uptake

-290- P6-2

SEPARATION OF Th AND Zr FROM ACID MEDIUM BY 3-FORMYL-4HYDROXY-N METHYL 2 (H) QUINOLINE

A.M.I. Ali and H.F.Aly Hoi Laboratories Centre, Atomic Energy Authority, 13759, EGYPT

3-formyl- 4-hydroxy N-methyl 2(H) quinoline (FHMQ) was synthesized and characterized. This compound was found to be not soluble in water or in nitric solutions of different concentration. The uptake of Zr and Th from nitric acid by FHMQ has been investigated. The effect of shaking time on the percent uptake was studied. It was found that the equilibrium uptake of Zr was reached in one step after 2hr while in case of Th 4 hr were required to reach equilibrium. The effect of nitric acid, metal ion and FHMQ concentrations on the % uptake, of Zr and Th was investigated. The loading capacity of FHMQ for Zr was studied. Studies on the retention capacity of 3-fomyl-4-hydroxy-N-methyl 2(H) quinoline showed that the capacity decreases by increasing the nitric acid concentration for both Zr and Th. From these results a selective method for separation of Zr from Th and for U(VI) was established using a floating bed column.

-291- P6-3

ADSORPTION OF Ba ON KAOLINITE, ILLITE AND MONTMORILLONITE AT VARIOUS IONIC STRENGTHS

GUI ten Atun and Elvan Ba^etin Department of Physical Chemistry, Faculty of Engineering, Istanbul University, Avcilar 34850 Istanbul, TURKIYE

The interaction of radionuclide ions with various soil fractions plays an important role in the extent of contamination of underground waters. Clays are the most important components in such interactions. In this study, the adsorption of Ba2* on three types of clays from Turkey has been investigated by means of a batch technique in solutions of sodium chloride Ionic strengths of solutions ranged from 10'Jto 10"'. The adsorption data were fitted to a Freundlich isotherm and empirical Freundlich parameters enabled the generation of a site distribution function. The selectivity coefficients were constant at low loading and decreased with increasing loading This behaviour was an indication of ion exchange process between Ba2 and Na' ions

-292- P6-4

THE ADSORPTION BEHAVIOR OF NATURAL SAND IN CONTACT WITH URANIUM CONTAMINATED SEA WATER

Giilten Atun and Ay ben Kilislioglu /. V.Muhendishk Fakultesi Kimya Boliimii. TURKEY

In the studies on the clearance of radioactivity from waste water, the method of adsorption has been used more and more as the easiest and the most accurate. In this study, we aim to study the interaction between uranium contaminated sea water and the sand in contact with the sea water, with respect to uranium adsorption by the sand and how this adsorption is affected by the changes in environmental conditions. We use different sea water from different sea regions and the natural sand in contact with this sea waters. Sorption of uranium by natural sand has been studied as a function of uranium concentration and temperature. The results have been analysed by the Freundlich and Dubinin-Radushkevich (D-R) isotherm over the entire range of uranium concentrations. By fitting the data to D-R isotherm, we calculated the adsorption energy and decided to type of the adsorption.

-293- P6-5

SOLVENT EXTRACTION STUDIES OF SILVER BY SPHERICAL LIGANDS INCORPORATING AROMATIC SUBUNITS

C. Chartroux, T. Rambusch, H. Stephan, K. Gloe", S. Ibach, M. Horn, F. Vogtle2' Instiiutfiir Anorganische Chemie, Technische Universitdt Dresden, D-01062 Dresden, Germany lnstilutflir Orgattische Chemie und Biochemie, Universitdt Bonn, D-53J2I Bonn, Germany

The development of selective host systems is of great interest for different applications from chemistry to medicine. In case of silver especially the design of spherical ligands containing aromatic Tt-donor sites or pyridine nitrogen donor atoms gives new possibilities for a selective complexation. So the compounds 1-4 have been synthesized and characterized in view of their complexation behaviour towards silver and some other metals ions. In this paper we will discuss the Ag* binding by these compounds using solvent extraction and molecular modelling studies. The extraction experiments were performed in the system AgNC>3 - HPic - H2O / ligand - CHCI3 using radiotracer technique. The investigations give a clear evidence of inclusion of Ag* in the cavities. In dependence on the structure and the number of 71- and N-donor centres the binding strength and selectivity are changing. Molecular modelling calculations of the ligands investigated and their silver complexes are very helpful for interpretation of the experimental data and allow to deduce structure-extractability relationships.

-294- P6-6

ACID EFFECT ON THE TcMm AND Mo" MUTUAL SEPARATION AND TRANSPORT ACROSS SUPPORTED LIQUID MEMBRANE EXTRACTION SYSTEM

M. Ashraf Chaudry Pakistan Institute of Nuclear Science and Technology P.O. Box No. 1356, Islamabad, PAKISTAN

Work on Tc99™ extraction using supported liquid membrane (SLM) has been performed with 2 tri-n-octylamine as carrier. (MoO4)" ions transport with TOA-xylene has also been studied with respect to HCI concentration (0.001 to 0.05M) in the feed solution. Tc99™ transport in the same HC1 concentration range has shown that while MOO4"2 ions flux is higher at < 0.01M HCI, in the 5 2 2 order of (15-20)xl0 mol/m .s, the TcO4" ions flux is in the range of (5-7) x 10'" mol/m .s. In case of sulphuric acid in the feed the transport of Tc99™ has been found to be higher, (28-55)xl I"11 mol/m2; while Mo99 transport is observed to be suppressed as the H2SO4 concentration in the feed solution increases, providing a useful method for extraction of Tc99™, produced from the disintegration of Mo with time. Membranes supports used are of polypropylene material. Effect of acid on Mo species present in the feed solution and the mechanism of transport through the SLM are also discussed.

-295- P6-7

SEPARATION OF TH-234 FROM Y-90

R. Chobola1, A. Vincze1, E. Erd6s\ J. Solymosi1, P. Mell1, L.T6rfik\ T.Ranga2, G.Volent2 'Technical University of Budapest, Department of Physical Chemistry, Radiochemical laboratory, Budqfoki u.8, H-'l521, Budapest, Hungary 2NPP Paks, 7031, Paks, Pf. 71.

A relatively simple procedure has been developed for the determination of Sr-90 in natural aqueous samples. The method comprises mainly from a Fe(III)-hydroxide coprecipitation step, followed by the separation of Y-90 with the mixture of -oxalate and yttrium-ammonium- oxalate salts. This method was tested on large number of natural water samples and Th-234 contamination could be observed in the prepared yttrium samples. The analysis has therefore been extended with the separation of thorium from yttrium, which is performed using DOWEX-50W-X8 cation exchange resin and citric acid as chelating agent. The experiences and results of this new method will be presented in our presentation,

-296- P6-8

PARTITIONING OF STRONTIUM FROM HIGH-LEVEL LIQUID WASTE (HLLW) BY DICYCLOHEXANO-18CROWN-6 (DCH18C6)

Song Chongli, Wang Jianchen, Wang Qiuping Institute of Nuclear Energy Technology, Tsinghua University, 100084 Beijing, China

'"Sr and 137Cs are the two toxic nuclides and major heat generators in high level radioactive waste (HLLW). In the partition and transmutation (P-T) concept, not only transuranium (TRU) elements but also caesium and strontium should be segregated from HLLW. A total partition process for segregating TRU elements, technetium as well as strontium and caesium from HLLW is developed in our Institute. The total partition process consists of three parts: a TRPO process for the removal of TRU elements, a Crown Ether Strontium Extraction (CESE) process to separate MSr from HLLW and an ion exchange process to remove 137Cs from HLLW by potassium titanium hexacyanoferrat (KTiFC) ion exchanger. After partitioning the HLLW will become a low and intermediate level radioactive waste that could be cementation and is suitable for shallow land disposal according Chinese regulation. In CESE process, 0.1 mol/1 dicyclohexano-18-crown-6 (DCH18C6) in 1-octanol was used as an extractant. The extraction properties of DCHI8C6 for strontium were studied in nitric acid and highly saline solution. A Strontium extraction calculation model (SECM) of the CESE process for strontium extraction was developed. The process was verified with simulated highly saline HLLW in a miniature centrifugal contactor set. Finally a hot test of the CESE process was carried out with genuine Chinese HLLW in the centrifugal extractor set The feed solution was the genuine HLLW raffinate from the TRPO process and its acidity was I 45 mol/L HNO.v In the hot test of the CESE process 10 extraction stages and 2 scrubbing stages were used in extraction section Four stripping stages was used in back-extraction section The results of the hot test were very attractive. More than 99.96% of strontium were extracted from the feed solution by DCH18C6 and above 99.84% strontium was stripped out of the organic phase by H?O. Non of the TRU elements was extracted with strontium by extractant Only about 0 4% of Cs were extracted and found in the Sr stripping stream. The hot test result proved that the CESE process was a promising process for removed strontium from HLLW

-297- P6-9

STUDY OF SORPTION PROPERTIES OF VARIOUS TITANIUM DIOXIDE MATERIALS

E. DanaCfkova, J. John, A. Motl, F. Sebesta, E.W. Hooper* Czech Technical University in Prague, Department of Nuclear Chemistry, Bfehovd 7, 115 19 Prague I, Czech Republic * AEA Technology, Harwell, Didcot, Oxfordshire 0X11 ORA, UK

Sorption properties of hydrated titanium dioxide ion-exchangers are known to depend on many various parameters such as their crystalline structure (anatase or rutile) or presence of any dopants, and on the method employed in their preparation, that influences namely the porosity and specific surface area of the resulting materials. To establish the influence of the above factors a comparative study of sorption properties of five various samples of titanium dioxide materials was performed. The samples used included three commercial TiO2 samples (Degussa P25, Germany; Pretiox AV-01 and Pretiox RG-14, Precheza, as. Pferov, Czech Republic) and two laboratory preparations (HTO suspension, AEA Technology Harwell Laboratory, UK; and TiO2-M material prepared in our laboratory from an intermadiate in the production of titanium white). All the samples were characterised by Surface Area Analysis, Powder X-ray Diffraction, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. The theoretical sorption capacities of the materials were determined from the respective ,,titration curves" - dependences of equilibrium pH established after addition of a certain amount of acid or alkali to the suspension of the TiO? materials. The highest sorption capacity (10.5 meq/g) was found for the HTO absorber For the TiO2-M material, the sorption capacity is 6 0 meq/g, while the sorption capacities of the remaining three materials were found to be similar (close to 4 meq/g). Sorption properties of the materials were compared for strontium and cobalt uptake. For both the ions, dependences of distributions coefficients (KD) on pH were measured in the pH range 1-13. Solutions with the concentration of Na ions 0.1 mole/L were used, the concentration of strontium or cobalt was ~ 10 5 mole/L. Radiotracer method was used for KD measurement (wSr, 60Co). The volume of solution (V) to mass of absorber (m) ratio was V/m = 100 in the all experiments. Establishment of the equilibrium was secured by contacting the ion-exchangers with the solutions for 43 hours. At high pH values, strontium was found to be efficiently uptaken by all the titanium dioxides used At pH - 12, the distribution coefficients of strontium exceeded the maximum determinable 4 Ku value (KD,m» = 6.10 mL/g) for all the samples Following the shape of the KD dependence on pH, the studied materials could be grouped into three groups. The first group represents the HTO sample - sorption of strontium started at pH ~- 1.6 and the value of KUm« was reached already at pH ~ 7 The second group includes Degussa P25 and T1O2-M materials - for both of them the sorption of strontium started at pH ~ 5.5 and the value of Kannx was reached at pH ~ 9.5. For the AV-01 and RG-14 materials, the value of Ku.n,» was reached only at pH > 12. Uptake of cobalt by the three better-sorbing materials (HTO, T1O2-M, Degussa P25) was 5 found to be different than the sorption of strontium. The Ki).mM value (2.10 mL/g) could have been exceeded only for the HTO and Degussa P25 materials. For the T1O2-M, the maximum KD reached was only 8.104 mL/g At pH values higher than pH ~ 8, the sorption of cobalt on all the materials decreases with increasing pH This phenomenon can be explained by changes in the speciation of cobalt at higher pH The correlation of the results of sorption studies with the physico-chemical parameters of the T1O2 samples is discussed in detail in the presentation.

-298- P6-10

REMOVAL OF 226Ra FROM AQUEOUS SOLUTIONS USING A CATION EXCHANGE RESIN

F. Serap Erees, Sema Akyil Ege University Institute of Nuclear Sciences, 35100 Bornova-hmir, TURKEY

Natural radioactivity is an environmental factor that has been present at the earth's surface since the formation of the planet. Water quality is one of the most important concerns in environmental studies because of its use for human consumption and its ability to transport pollutants. The presence of natural radioactivity in ground water has long been observed. Radium is insoluble in water and does not form any soluble complexes that enhance its dissolution into ground water. In this study, removal of" 6Ra from aqueous solutions using a cation exchange resin has been investigated 226Ra in aqueous solutions was concentrated by using Dowex 50W which is a cation exchange resin The resins were converted into barium-charged from using analytically pure barium chloride solutions. Then, resins were washed with distilled water to remove excess of barium Analytically pure 2MRa chloride solution and barium loaded resins were treated under the various experimental conditions using batch method. Uptake 226Ra on Dowex 50W was examined as a function of barium concentration, shaking time and pH The resins were dried and stored in cylindrical plastic containers. The container was kept for 30 days to attain radioactive equilibrium between radium and radon doughter product The "('Ra activity of the resins was determined by using gamma spectroscopy.

-299- P6-11

SOLUBILISATION OF SALTS BY COPPER DI-(2-ETHYLHEXYL)PHOSPHATE BASED ON pH-TITRATION DATA

Golovanov V.I., Kuznetsov S.M. Chelyabinsk Stale University

In the report [1] the new mechanism of extraction was discussed, based on disproportion of salts to acidic and alkaline forms by the example of a large number of simple electrolyte extrac- tions with Fe(D2EHP)3 (FeX3) solutions: rKt* + An" + (z+l)A

    -300- P6-12

    SEPARATION OF RARE EARTHES BY EXTRACTION WITH NEUTRAL ORGANO-PHOSPHORUS COMPOUNDS IN PRESENCE OF COMPLEXONES

    Kopyrin A.A., Piartman A.K., Keskinov V.A. St-l'etersburg State Institute of Technology, Moskovsky Ave., 26, St-Petersburg (Russia)

    Isolation and the separation of lantanides by neutral organophosphorus compounds from the nitrate media, containing complexones permits to increase the separation factors of nearest REE of yttrium group, as well as heavy REE and yttrium. In the present work separation of modeling and practically important mixes of lantanides (III) of yttrium group and yttrium (III) from concentrated solutions of the ammonium or litium nitrates (5-8 mol/1), containing EDTA and DTPA or their salts was studied at variable composition of initial raw material, concentration of salting-out agents and pH (acidity). Stoichiometry and constants of stability of formed complexonates of REE in concentrated solutions of ammonium and litium nitrates, constants of a extraction of nitrates of REE by TBP, TiAP, DiOMP and DiAMP from water solutions of salting-out agents were determined. Physico-chemical and mathematical models in view of complete basis of proceeding homogeneous and phase equilibria, describing the distribution of REE depending on a structure of initial raw material, pH and concentration of ammonium or litium nitrates and REE nitrates in a water phase are indicated. Is established, that the increase of concentration of a ammonium or nitrates results in increase of the separation factors of of a yttrium and heavy REE. Optimum conditions for clearing of a yttrium from heavy REE with use of neutral organophosphorus compounds, complexones and ammonium (lithium ) nitrates.

    -301- P6-13

    REMOVAL OF NATURAL RADIONUCLIDES FROM DRINKING WATER BY ION EXCHANGE

    Jukka Lehto, Kaisa Vaaramaa and Timo Jaakkola Laboratory of Radiochemistry, University of Helsinki, Helsinki, Finland

    In Finland, as well as in many other European countries, where drinking water is taken from drilled wells, considerable concentrations of natural radionuclides can be found in water. Most important of these nuclides are 222|226Rn, B8U, 226Ra, 210Po and 210Pb. Radon is a gas and it is mainly removed by aeration. Of the other nuclides uranium, radium and polonium are alpha emitters and lead a beta emitter. To reduce excessive radiation doses generated by these nuclides effective separation methods have been studied. This study is a part of EU's NFS Programme's project FI4PCT960054 in which a wide variety of separation materials and methods are being evaluated for the removal of these radionuclides from drinking waters. Ion exchangers reported here belong to two cathegories: organic ion exchange resins and inorganic ion exchangers. In the first phase all exchangers were equilibrated with a ground water simulant containing 2.18 mmol/1 Na, 0.84 mmol/1 Ca, 0.41 mmol/1 Mg, 0.42 mmol/1 K, 2.44 mmol/1 HCO3\ 1.70mmol/l CI" and 0.42 mmol/1 SO4° as main components. After reaching the equilibrium composition of the exchangers with this simulant, distribution coefficients (KD) of the four radionuclides were determined by equilibrating a sample of the exchangers with a sample of the 233 226 210 208 ground water simulant labelled with U, Ra, Pb or Po. Theoretically KD gives, in the conditions where it was determined, the processing capacity, i.e. how many litres of solution can be treated up to the 50% breakthrough with one kilogramme (or litre) of exchanger bed. Exchangers which showed best performance for each nuclide are being tested in column mode experiments for the removal of these radionuclides from real ground waters. By this way, not only the processing capacity, but also the decontamination factor can be determined.

    233 226 233 226 Organic resins KD for U KD for Ra Inorg. exchangers KDfor U KD for Ra Strong acid resin 14mi/g 15,200 ml/g Sodium titanate 7,600 ml/g 2,000,000 ml/g Weak acid resin 181,000 11,600 Zeolite A 82 106,000 Strong base resin 10,000,000 0 Mordenite 49 45,600 Weak base resin 2,110,000 0 Manganese oxide 650 5,400,000 Aminophosphonate* 1,110,000 1,800 Na-4-mica 35,300 146.000 Iminodiacetate* 53,000 980 * chelating resins

    KD's reveal that ordinary anion exchange resins are best for the removal of U, which is rather natural since uranium is mainly present as UO2(CO3)2* in ground waters. It is, however, possible that the aminophosphonate resin can effectively strip uranyl ions from the anionic carbonate complex and can find use in the removal of uranium from high salinity waters which are more difficult for anion exchange resins. For Ra the best performance was obtained with inorganic ion exchangers manganese dioxide and sodium titanate. From these sodium titanate is a commercial product. Preliminary experiments with polonium have shown that it is mostly adsorbed on bottles, tubes and filters and therefore no definite distribution coefficient values can be obtained Experiments to determine the species of polonium, such as colloids, in ground water are under way.

    -302- P6-14

    USE OF IMMOBILIZED TANNIN ADSORBENT FOR REMOVAL OF Cr (VI) FROM WATER

    L. Lima, S. Olivares, F. Martinez, J. Torres, D. De La Rosa, C. Sepulveda* Institute Superior de Ciencias y Tecnologia Nucleares. Salvador Allende Ave. y Luaces, Havana 6163, Cuba. *Instituto de Pesquisas Energeticas e Nucleares.C: P. 11049 -CEP 05422 - 970, S. Paulo, Brazil

    Adsorption of Cr (VI) by two tannin sorbents is evaluated using radiotracers. Evaluation of sorption process shows that Cr (VI)- tannin molecule binding is the principal responsible for adsorption. High sorption capacities were registered for both sorbents at pH 2. For Eucaliptus Salipia Sm sorbent (ETS) sorption capacity is 0.92 ± 0.03 mmol/g and for Lysiloma latisiliqua sorbent (LTS) is 3.8 ± 0.3 mmol/g. Influence of different ions present in water is examined. High sorption capacity is reported for LTS in sea and tap water samples . It represents 90 - 94 % of adsorption in distilled water.

    -303- P6-15

    EXTRACTION OF SELECTED BASES BY 0.1 M HCI SOLUTIONS OF BIS-1.2-DICARBOLLYLCOBALTATE INTO CHLOROFORM

    Oldfich Navratil, Zden£k Skaltfan Department of Chemistry, Military University 68203 Vyskov, Czech Republic

    Bis-l,2-dicarbollylcobaltate amons, labelled by 60Co, create ionic associates with cations of some organic bases, especially with psychic effect on human organism. Their stability and partition between aqueous 0.1M HCI and chloroform were investigated radiometrically. The stability of the corresponding ionic associates increases in the sequence 1,6-diaminohexane < aniline < diethylamine < pipendine < pyridine < ephedrine < scopolamme < tnethylamine < codeine < ethylmorphine < l-(l-phenylcyclohexyl)pipendine (agent SERNYL, PCP) < cocaine = physostigmine = 3-quinuclidinylbenzilate (agent BZ) < LSD The values of Kn K.& were calculated; KD and K.& are partition and formation constants of ionic associates.

    -304- P6-16

    KINETICS OF TRANSPORT EXTRACTION BASED ON SOLVENT SUBLATION

    S. PaWgyi Stale Office for Nuclear Safety, Senovd'ne namesti 9, lit) 00 Prague I, Czech Republic

    Solvent sublation is an option to ion-flotation, where the sublate formed between surface active agent (collector) and an oppositely charged solute (colligend) is adsorbed on the bubble surfaces of an ascending gas stream and collected into an immiscible liquid layer (organic solvent) placed on top of the water column. This technique is a collection process opposite to precipitation and can be recognised as an alternative to normal, equilibrium solvent extraction and viewed as a non-equilibrium transport extraction. The kinetics of this transport extraction has been studied and relevant equations has been derived, from which the mass-transfer rate constant (kr) and the separation efficiency can be calculated in dependence on time (t). The mass distribution constant of a solute between the surface of the carrier gas bubbles and aqueous phase (ks) can also be evaluated. A model system of the molecular L"l - cationic N-cetylpyndinium chloride (CPC) surfactant complex pair were used under static conditions with a stagnant aqueous phase and benzene as stationary organic solvent immiscible with water. Separation efficiencies up to 95% were obtained with a 400-fold preconcentration of radioiodine into 10 cnr of benzene in the separation of "'I from 4 dm of deionized, tap and river water samples in about 1 h using N2 carrier gas at a flow rate of 60 cm3/min.

    Fitting the experimental values of the separation efficiency (E) in the dependence of E«p= fi;t), the following values of k, were calculated: 0,180 min'1, 0,143 min"1 and 0,093 min', respectively, = + 1 using equation Eu,COr EmM [1 (k, . t)"']" , where Emax is a fitting parameter for t = oc. From these values, the following half-times (t,,2 = l/kr) of this transport extraction can be obtained: 5,6 min, 7,0 min and 10,8 min, respectively From the known volume of the aqueous phase and carrier gas flow-rate, the values of k, were also calculated, using equation kr = k« veJV^. These are 12,0 mol/mol, 9,6 mol/mol and 6,2 mol/mol, for a fitting parameter of 100,9%, 101,4% and 104,7%, respectively.

    A statistical investigation of the data shows a good correlation between ks and k, for the calculated average values of Emra = 100,1± 1,5%, the ratio of ks to kr being around 66,7 min, independently on the sample volume and carrier gas flow-rate. Under these conditions the average value of k, is 12,8±2,4 mol/mol.

    -305- P6-17

    MATHEMATICAL DESCRIPTION AND MODELLING OF PROCESSES OF SEPARATION AND PURIFICATION OF LANTHANIDES BY SOLVENT EXTRACTION AND ION EXCHANGE

    Piartman A.K., Kopyrin A.A., Keskinov V.A., Berinsky A.E. St-Petersburg State Institute of Technology, MoskovskyAve., 26, St-Petersburg (Russia)

    In the report physico-chemical and mathematical models of the description of distribution of lanthanides (REE) in multicomponent systems, containing neutral organo-phosphorous compounds and their mixtures, salts of quaternary ammonium bases and their mixtures with neutral organophosphorous compounds, acidic organophosphorous compounds and their mixtures with neutral organo-phosphorus compounds are considered Main principles of selection of efficient extraction systems and optimisation of technological processes are formulated. It has been found that the highest selectivity of extraction systems at separation of nearest REE (or groups of elements) is reached by choice of conditions, at which in a organic phase solvates of a REE, possessing various stoichiometry or constants of extraction will be formed, as well as at a finding of a structure of a water phase (concentration of REE, salting-out agent, acidity, etc.), where maximum distinctions in stability of nitrate complexes and hydration state of metal ions are provided. Physico-chemical and mathematical models of the description of distribution of lanthanides, as well as accompanying impurities in multicomponent systems, containing polymer materials (resins) with chemically bonded fiinctional groups, capable to form the co-ordination compounds in a phase of the resin and use of found laws for deep clearing of lanthanides of impurities are considered.

    -306- P6-18

    RESEARCH ON INTEGRATION PROCESS OF NUCLEAR FUEL CYCLE BACKEND

    Wu Qiulin, Han Bingbin, Zhu Yongjun Institute of Nuclear Energy Technology, Tsinghua University, P.O.Box 1021, Beijing, China, P.R.

    The paper presented an integration process of nuclear fuel cycle backend which combined two processes. One is the Purex process which is applied to nuclear fuel reprocessing And the other is TRPO process which is proposed by China to removal and recovery U, Pu, and Am etc. from HAW. Preliminary calculations on this concept process were conducted using genetic algorithm Optimised operational parameters were obtained. TRPO is a mixture of trialkyl phosphine oxides. Experiments showed that the loading capacity of 30% TRPO-kerosene for U(VI) and Nd is considerably high under the TRPO process condition (acidity after equilibrim=lmol/l). So it is possible to recover a part of U and Pu in TRPO process instead of Purex process. This arrangement can improve decontamination from fission products by increasing the saturation of U in the 1A cycle Therefore the cycle number of U and Pu will be decreased. Because MOX fuel have been used in the power reactor, the MOX fuel concept can applied for the final Pu product of Purex Process. After stripping the organic phase loaded U and Pu by dilute acid, the organic product of U and the aqueous mixture product of U and Pu will be obtained. This arrangement can prevent nuclear proliferation And the cycle number of U and Pu will be decreased to only one. In the concept process, the characteristic of fission products Zr, Nb, Ru should be noticed because the TRPO has some ability to extract these fission products. Some preliminary research were conducted to improve the decontamination of these fission products. The calculations demonstrated that the TRPO process can be integrated with Purex process and the Purex process can be simplified to only one cycle.

    -307- P6-19

    PROXIMATE ANALYSIS OF CONCENTRATION OF RADIOACTIVE CEASIUM IN NATURAL WATER

    V. Remez Joint Stock Company "Compomet Cantec", 8th March St., Yekaterinburg, 320014, Russia

    The technology of obtaining the sorbent on the base of ferrocyanide of iron-potassium on cellulose earner was worked out. The sorbent is capable to extract effectively the isotops of ceasium (Cs) from the various natural solutions (sea and fresh waters milk, juices and etc). The usage of the sorbent allows just within few minutes to completely concentrate in practice the isotops of ceasium from the water samples with the volume of tens and hundreds liters. Due to preliminary concentration on the sorbent, the sensitivity of this proximate analysis is increasing thousands times as much. The sorbent in quantity of 50-100g allows to extract 95-98% of ceasium from 500-1000 liters sample (sea water borehole water and etc) in 1-2 hours. The usage of this sorbent allowed to conduct the proximate analysis of multiple boreholes within 30km area of Chernobylskaya NPP, drinking water and milk in the range of regions of Belorussia Ukraine and Russia which suffered of the Chernobyl catastrophe and also the rivers Techa and Enisey were analized nearby the places, where the rediochemical plants are located.

    -308- P6-20

    WORKING INSTALLATION FOR PURIFICATION OF WATER FLOWS BY THE METHOD OF THE CHEMICAL ISOTOPE EXCHANGE OF HYDROGEN WITH WATER Y.A.Sakharovskii, B.M.Andreev, E.P.Magomedbekov, Y.S.Park, M.B.Rosenkevich D. Mendeleev University of Chemical Technology of Russia (RChTU) MHisskayaSq., 9, Moscow 125190, Russia (095)496-9264

    The modern condition of a nuclear industry and power has resulted in occurrence of ecological task of purification from tritium of water and gas flows and its localisation... Earlier we reported on use of a chemical isotope exchange between hydrogen and water for practical realisation of punfication heavy water wastes from protium with reception of conditional heavy water In the present report is informed creation, startmg-up and adjustment works and first experience of operation of installation, in which the same technology is realised with reference to deep punfication of water flows from tritium. The specificity of the system water - hydrogen is characterized by that the absolute value of thermodynamic isotope effect (

    -309- P6-21

    SOME EXAMPLES OF RADIOCHEMICAL SEPARATIONS USING AMPHOTERIC ION EXCHANGE RESINS

    Zbigniew Samczyiiski and Rajmund Dybczynski Department of Analytical Chemistry, Institute of Nuclear Chemistry and Technology, ill. Dorodna 16. 03-195 Warszawa, POLAND

    The usefulness of the amphotenc ion exchange resins Retardion 11A8 and Chelex 100 for radiochemical separations is presented. Resins of this class contain, in contrast to monofiinctional exchangers, anionic and cationic sites. Under appropriate conditions amphotenc resins can retain simultaneously both anions and cations from external solutions. This may offer new interesting separation possibilities. Retardion 11A8 contains strongly basic quaternary ammonium groups and an equivalent amount of weakly acidic carboxylate groups. Ion exchange behaviour of about twenty elements in hydrochloric acid and ammonia solutions by batch equilibration using radioactive tracers was investigated. The results indicated, that there exist pronounced concentration ranges where cadmium is retained by Retardion 11A8 in the form of chloride complexes from HCI solutions, as well as in the form of amine complexes from NH3 solutions. The ion exchange separation procedure based on a stepwise elution using HCI and NH3 solutions of appropriate composition was developed. The conditions necessary for keeping cadmium on the column when changing from anion to cation exchange function were established. Selective separation of cadmium from practically all accompanying elements with the aid of above mentioned procedure was used in our "very accurate" method for the determination of Cd in biological materials by radiochemical NAA. Analytical results obtained for several biological certified reference materials for Cd content, where the analyte concentration covered nearly five orders of magnitude, showed excellent agreement with the certified values. Chelex 100 contains immodiacetic groups capable of forming chelate complexes with numerous metals depending on pH of the mobile phase. The nitrogen atom of this group which has a free electron pair can be protonated in acidic medium. Hence, under these conditions, the functional groups become weakly basic ammonium groups which can retain metal anionic complexes. In this way, Chelex 100 commonly regarded as cationic (chelating) ion exchanger is in fact amphotenc resin and its ion exchange function is affected by acidity of the external solution. In order to find potential new interesting separations, ion exchange behaviour of about twenty ele- ments by batch equilibration was established in the following systems: Chelex 100 - HCI solutions, Chelex 100 - pH buffer solutions and Chelex 100 - NH3 solutions. The results of batch equilibration followed by column experiments enabled to devise several new radiochemical separations by ion exchange chromatography. They are, in general, based on the differences in stability of the following complexes: • metal with iminodiacetic groups (chelates) • amine complexes • chloride complexes Some examples of binary and multicomponent separations employing both cation and anion exchange function of Chelex 100 are presented.

    -310- P6-22

    EXTRACTION OF SOME METALS WITH IMIDOPHOSPHORUS REAGENTS

    Petr Sladek, Old rich Navratil, Eckhard Herrmann Department of Chemistry, Military University, 68203 Vyskov, Czech Republic Hochschule fiir 1'echnik unii Wirtschaft, D-01069 Dresden, Germany

    Polydentate |i-imido organophosphorus compounds, in particular bidentate aryl esters of lmidodiphosphoric acid, (RO)2P(X)NHP(Y)(OR)2 where X,Y = 0 or S and R aryl group serve as efficient extractants for the separation of many metals by solvent extraction. Many of these reagents are Bronsted acid HA able to form the extractable neutral chelate complex1 MAn with metal tons M"' In general tnvalent and polyvalent metals, particularly and rare earth elements, are extracted selectively if oxygen2 derivatives are employed. So far, little attention has been paid to tndentate and polydentate derivatives. Examination of such reagents and comparison of the extraction efficiency for some metals were the objectives of the present work. The reagents on the base of sulphur analogs are employed as efficient reagents for the separation of many metals as well as platinum, silver, and mercury etc Since the sulphur derivatives have not been mutually compared in detail, such comparison is presented Special attention is paid to the distribution of mercury, which finds use as a detector in the determination of some chemical warfare agents

    References

    [1 ] SLADEK P., NAVRATIL 0, NOUAMAN M, GRONWALD A., HERRMANN E Solvent Extraction Research and Development, Japan, 2, p. 1, (1995) [2] NAVRATIL O., SLADEK P., T0KAR0VA A, HERRMANN E., NOUAMAN M : Collect. Czech. Chem. Commun., 62, 620 (1997) [3 ] NAVRATIL O., TOKAROVA A., SLADEK P., HERRMANN E , NOUAMAN M Collect. Czech. Chem. Commun , 62, 375, (1997).

    -311- P6-23

    STUDY OF MERCURY SORPTION ON VARIOUS INSOLUBLE FERRO- AND FERRICYANIDES

    S. SmrikovS, F. Sebesta Czech Technical University in Prague, Department of Nuclear Chemistry, Bfehova ~, 115 19 Prague I, Czech Republic

    A set of 8 various insoluble ferncyanides of Fe3*, Co2', Zn"*, Cu2", or NfH and 11 ferrocyanides of Cu2*, Co2*, Ni2*, or Zn2* was prepared by precipitation of soluble salts of appropriate cations with K,[Fe(CN)6], IC[Fe(CN)0], Na4[Fe(CN)c], or H4[Fe(CN)6] The products were dried and fraction with grain size < 0 1 mm was separated. The obtained materials were characterised by elemental analysis and water contents. The batch sorption experiments were performed to determine dependence of mercury sorption 5 onto fern- or ferrocyanides from 0.001 - 4 M HN03 + 0.1MNaNO3 + 3.10' M Hg(NO3)2 solutions. The sorption of mercury using ferricyanide sorbents is significant in all acidity range (KD values from 200 to 40.000 mL/g). For zinc ferncyanides, mercury sorption increases with increasing HNO3 concentration in all the acidity range tested. For the other absorbers the highest sorption of mercury takes place in 1 - 2M HNO3 + 0.1M NaNO.? solutions. Sorption of mercury onto ferrocyanides was studied in a similar way and using the same conditions as in the case of ferncyanides. Highest sorption of mercury onto ferrocyanides was found to take place in 1 -2M HNO3 + O.lMNaNO* solutions. In such cases, maximum K» values achieved ranged from 200 to 7500 mL/g. Sorption of mercury onto both the ferri- and ferrocyanides was found not to significantly depend on either the choice of the counter-cation or variations of the absorber preparation procedure. Comparison of sorption capacities for mercury uptake from 2M HNO3 + 0.IM NaNCh was performed for all the materials tested. Sorption capacities for mercury uptake were found to be rather high for all the samples tested The maximum sorption capacities determined from sorption isotherms of four selected absorbers range from 1.4 to 7.1 mmole Hg/g of powdered absorber

    -312- P6-24

    SEPARATION OF CESIUM-137 and STRONTIUM-90 IN MULTICOMPONENT SYSTEMS BY USE OF INORGANIC AND POLYMER MATERIALS

    LA. Sobolev"*, S.A. Dmitryev*', S.V.Stefanovsky "\ A.A. Kopyrin, A.K.Pyartman, V.A.Keskinov, M.A.Pleshkov ''NPO "Radon", Moskow, Russia St-Petersburg State Institute of Technology, 198015, St-Petersburg, Russia

    A new method of composite sorbents synthesis, which includes cations and anions sorption by organic materials and preparation of composite material inside sorbents pellets, is proposed. Samples of sorbents on the basis of ion-exchange resins KU-2x8(KU-23), AV-17, VP-1AP, multivalent metal salts (Zr(IV), Fe(III), Cr(III) hydroxides and phosphates, potassium and transition metals (Cu, Ni, Co, Zn ferricyanides) are prepared. Composite materials selectivity to radionuclides 137Cs and 90Sr separation from complex water solutions was studied. Distribution coefficients and separation factors of several element pairs, i.e. K/Cs, Na/Cs, Ca/Sr, Na/Sr were determined as a function of water phase composition. Coefficients of mutual diffusion for mentioned above ion-exchange processes appeared to be in the range 10'8-10"9 cm/sec. The possibility of composite sorbents application for radionuclides separation from liquid radioactive wastes is considered. Sorbents dynamic exchange capacities are determined. It was found that if the temperature is below 200°C the change of sorbents weight is dew to dehydration processes. In the temperature range 200-600 °C the loss of weight occurs because of organic material destruction and in the range 600-900°C - because of solid oxide structures formation. The obtained results are used for selection of optimal conditions for radionuclides utilisation.

    -313- P6-25

    FIBROUS SORBENTS FOR PURIFICATION OF COMPLEX COMPOSITION SOLUTIONS AND MILK FROM Cs RADIONUCLIDES REMOVAL

    V.V. Strelko, V.V. Yatsenko, V.K. Mardanenko, V.G.Milgrant Institute ofSorption and Problems of Endoecology of National Academy of Sciences of Ukraine, 13 General Naumov Str, Kiev, 252164, Ukraine.

    A novel methods for producing of fibrous sorbents on the base of viscose and heavy metal ferrocyanides (ferrum, copper, zinc) were proposed. Originally of methods consists in fact, that formation of fibre and heavy metal ferrocyanide in it's volume takes place simultaneously. Fibrous sorbents may be processed into unweaved material with 3-8 mm thickness and specific density 8-12 g/dm2. They can be used for manufacturing of filters of any size and form. The Kd values, obtained for Cs-137 removal from mineralised solution (10 g/1 of IMa, K, Ca, Mg chlorides ) by this sorbents, were 104—105. But only filter with ferrum ferrocyanide could be applied for purification of milk, contaminated by caesium radionuclides in native way, because this filter is practically indifferent towards milk components, even microelements content. Milk purification degree was up to 90-95%, when filtration rate was (1-1.5) 1/min.dm2 and initial contents of caesium radionuclides was 200-800 Bq/1. Hydrolytical stability of fibrous sorbents was determined too.

    -314- P6-26

    COMPARISON OF CAESIUM SORPTION ON INSOLUBLE HEXACYANOFERRATES (II) AND (III) FROM ACIDIC SOLUTIONS

    K. Uvirovd, F. Sebesta Czech Technical University in Prague, Department of Nuclear Chemistry, Bfehova 7, 115 19 Prague /, Czech Republic

    A lot of information on the sorption of caesium on hexacyanoferrates (II) and/or (III) is available in the literature. Comparison of these data is often complicated by incomplete information on the hexacyanoferrates composition, methods used for their preparation, different testing procedures, etc. This study was aimed to choose the most suitable ion-exchangers for caesium separation from acidic media and to test the possibility of their regeneration. For the tests, eleven samples of simple metal and mixed alkaline and metal hexacyanoferrates (II) of Co2*, Ni2*, Cu2* and Zn2* were prepared (further denominated as FC). Further, eight samples of hexacyanoferrates (III) of Fe *, Co2*, Ni2*, Cu2* and Zn2* were prepared (further denominated as FIC) for the testing of caesium sorption from acidic media. The individual samples of the exchangers differed also in the procedure of their preparation. All exchangers studied were analysed (elemental composition) and its content of water was determined. The study of sorption of caesium on the FIC and FC was carried out in batch experiments from nitric acid and/or hydrochloric acid solutions containing 0.1M NaNC>3, using V/m = 500 mL/g and caesium concentration of W* mole/L. The concentration of mineral acid was varied in the range 10'3 - 4.0 mole/L. The solid and liquid phases were separated by centrifugation after 120 min of shaking. The inhibitory action of hydrazine on the oxidation of FC to FIC in concentrated nitric acid solutions was also evaluated. Distribution coefficients KD (mL/g) were used for the comparison of sorption properties of ion-exchangers tested.

    -315- P6-27

    THE EXTRACTION OF RADIOISOTOPES OF ALKALINE EARTH METALS AND SODIUM BY CROWN ETHERS WITH DICARBOLLYLCOBALTATE

    P. VaiSura Department of Analytical Chemistry, Institute of Chemical Technology, 166 28 Prague, Czech Republic E-mail: Petr. [email protected]

    The extraction of ~"Na, Ca, 3Sr and Ba by the nitrobenzene solution of dicarbollylcobaltate has been investigated and the influence of the presence of various substituted and unsubstituted crown ethers was shown. The extraction of alkali earth ions in absence of crown increases in the order Mg" > Ca" > Sr" > Ba" , but the difference of values of exchange extraction constants between Mg" and Ba" is less than one order of magnitudes. The presence of 15-crown-5 increases both, the distribution ratio and the mutual extraction selectivity of alkali earths. The logarithm of synergistic factor for calcium is log S = 3.1, for strontium log S = 6.0 and for barium log S = 7.4. For the extraction of strontium and barium only the complexes Sr(15C5)2"+ and Ba(15C5)2"+ exist in the whole concentration ratio investigated On the other hand both Ca(15C5)~ and Ca(15C5)?" have been found during the extraction of calcium. The greatest value of separation factors a(Sr/Ca) s 1000 was found in the concentration region where the complex Ca(15C5)2~+ prevails. The equilibrium constants for the above complexes in nitrobenzene have been calculated. The extraction systems with 15C5 are suitable for inactive carrier determination in radioisotopes o( Sr and Ba The extraction of Na in the nitrobenzene - dicarbollylcobaltate system is low. The addition of DCH18C6 has a little effect on the distribution ratio of sodium (synergistic coefficient value S = 2) On the other hand, the addition of DB18C6, with almost same diameter of cavity as DCH 18C6 causes the increase of distribution ratio of sodium with S=500. This difference is caused by the competition of H ion. The protonation constant of DB18C6 in nitrobenzene is log K=4.0, the value of protonation constant of DCH18C.6 is log K=5.7. The distribution ratio of sodium in the system with 15C5 is almost same as with DB18C6.

    -316- P6-28

    STUDIES ON THE EXTRACTION BEHAVIOR OF TECHNETIUM IN CHINESE TRPO PROCESS

    Feng Xiaogui, Liang Junfu, Song Chongli, Jiao Rongzhou Institute of Nuclear Energy Technology, Tsinghua University, I'.O.Hox 1021. Beijing, P.R.China

    The extraction behaviour of TcO4 by TRPO-kerosene from nitric acid solution was studied The extraction was found to proceed according to the reaction H' + TCO4 + 2TRPO = HTcO4 •2TRPO A discussion of possible reaction mechanisms was presented, along with values of AG, AH, AS and the appearance equilibrium constant for the extraction reaction. The effects of Na', 3 ! 2 4 Nr\ Al'~, Fe *, RE \ UO2 , Zr ' and HNO? concentrations on the extraction of TcO4 were studied respectively. It was found that the distribution coefficient of TcOj increased with the increase of the acidity until a maximum was reached at 0.35 mol/l HNO3 , then the distribution coefficient of TcO4 decreased with the increase of the acidity The distribution coefficient of TcO4 decreased while the concentrations of Na , Ni~ , Al ', Fe , RE increased accordingly On the contrary, the extraction of Ted was enhanced in the presence of UO2" or ZrJ\ and the coextraction of JCOA with UO2"' and Zr4 was found. Finally, the stripping behaviour of technetium in 30% TRPO-kerosene solution by nitric acid, sodium hydroxide, sodium carbonate and ammonium carbonate solution was studied and stripping parameters were given. Technetium could be stripped more efficiently by deionized water, <0.0I%(w/w) ammonium carbonate and <0. l%(w/w) sodium carbonate than by nitric acid.

    -317- P6-29

    SEQUENTIAL SEPARATION OF ACTINIDES AND LANTHANIDES BY EXTRACTION CHROMATOGRAPHY

    M. Yamaura & H. T. Matsuda Institute de Pesquisas Energeticas e Nucleares

    CMPO/TBP sorbed on Amberlite XAD7 resin was used for actinides and lanthanides separation from nitric acid solutions using extraction chromatographic technique. The distribution ratios of actinides and lanthanide fission products (Ce, Eu) as a function of acid concentration and some complexing agents were determined. In strong HNO3 medium (>lmol/L) the tri-, tetra- and hexavalent actinides as well as the lanthanides have shown great affinity for CMPO/TBP/XAD7 resin The same behaviour was verified in HO medium except to trivalent actinides and lanthanides which show lower distribution values in the same acid range. The effect of some complexing agents as DTPA, ammonium oxalate were also investigated. In DTPA only hexavalent actinide showed higher distribution value. On the basis of these differences, an alternative process for actinide-lanthanide separation and each actinide separation from the others is proposed.

    -318- P6-30

    SEQUENTIAL EXTRACTION OF RADIONUCLIDES FROM AEROSOL FILTERS FROM THE VENTILATION STACK OF NPP JASLOVSKE BOHUNICE (SLOVAKIA)

    VSra BeCkovii, Petr Rulfk National Radiation Protection Institute, Prague, Czech Republic

    Results of sequential leaching of aerosol filters from nuclear power plant (PWR, type VVER 230) ventilation stack aimed at speciation of discharged radionuclides are presented. The y-emitting radionuclides were partitioned into five fractions: exchangeable, extractable in gastrointestinal tract, bound to Fe and Mn oxides, soluble in 7M HN03, and residual. Contents of radionuclides in the fractions were established by means of semiconductor y-spectrometry. Ionic forms and forms extractable in GIT of Cs-137, Cs-134 and Ag-llOm were found. The activation products Mn-54, Co-58, Co-60, Sb-125, and Sn-113 were found to be only partially soluble in hot nitric acid and mostly insoluble. The results agree with the findings from our previous studies.

    -319- P6-31

    EFFECT OF HUMIC ACID ON THE ELECTROPHORETIC MOBILITY OF URANIUM (VI) IN AQUEOUS SOLUTIONS

    P.BeneS1, K.R.Czerwinski2 and J.Dolansky1 'Department of Nuclear Chemistry, Czech Technical University, Brehovd 7, 115 19 Praha 1, Czech Republic 1Department of Nuclear Engineering, Massachussetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachussetts 02239-4307, USA

    Electrophoresis of hexavalent uranium in aqueous solutions containing humic acid (HA) Gohy-573 was studied with the aim to charactense the uranium-humic acid (U-HA) complexes formed Electrophoretic mobility of uranium towards cathode and anode was determined using a free-liquid electrophoresis, as a function of pH and concentration of humic acid and uranium. Experiments with solutions of 1.10 mo!/l uranium in absence of humic acid indicated hydrolysis of uranium at pH 3-5. Similar hydrolysis, probably accompanied by the formation of pseudocolloids, was also found for 1.10"6 mol/1 uranium. Addition of humic acid in 5.6.10"*, 3.1O"5 or 1.1CT4 mol/1 concentration to 5.10'7 - 2.10"" mol/1 solution of uranium at pH 4.0 caused decrease in uranium mobility towards cathode and increase in its mobility towards anode, due to the formation of neutral and/or negatively charged U-HA complexes The changes were more pronounced at higher ratio [HA]/[U] concentrations. Abundances of U-HA complexes and their mean mobilities towards anode were calculated from the results obtained. It was found that the mobilities decreased with the increasing [U]/[HA] ratio due to saturation of negative charge of the humic acid with positively charged uranium species, mainly UO2"

    -320- P6-32

    2+ COMPLEXATION OF UO2 BY THE SIDEROPHORE MYCOBACTIN S

    M. Bouby, I. BUIard and J. MacCordick IReS, CNRS/IN2P3- ULP, Chimie Nucleaire, Bat. 35, B.P. 28, 67037 Strasbourg Cedex 02, France.

    Numerous complexing molecules may play an important role in the migration of radionuclides at nuclear repository sites. Of these molecules, the behaviour of a compound of bacterial origin appeared of interest with respect to complexing power towards uranyl ions. A substance of choice was the siderophore Mycobactin S, extracted from the widespread bacterium Mycobacterium smegmatis. The siderophores are specific molecules synthesized by the bacteria to solubilize and transport iron (III) ions within the cells. However, several studies have shown that these compounds can complex other cations such as those of actimdes. It was thus of interest to investigate the behaviour of this siderophore towards uranyl ions. The present study is an attempt to shed light on the role of this type of molecule on radwastes In spite of the hydrophobic properties of the mycobactins, their possible use as an extractant merits attention. The results presented here are based on an appropriate complexation model that takes into account the effect of ionic strength in ethanol. Further studies with a hydrophilic siderophore (pyoverdme A) enable a comparative investigation of the relative selectivities of two different types of siderophore towards the same cation

    -321- P6-33

    KINETICS OF METAL-LIGAND INTERACTIONS IN EQUILIBRIUM SYSTEMS USING RADIOTRACERS

    J. van Doornmalen, J.T. van Elteren, Z.I. Kolar and J.J. Kroon Inter/acuity Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 .IB DELFT, The Netherlands

    The physico-chemical forms of heavy metals occurring in natural waters are regulated by the presence of a multitude of different ligands, such as inorganic anions, humic and fulvic acids, colloidal matter and paniculate matter Information about metal speciation and especially the kinetics of metal-ligand interactions is essential for the elucidation of mobility, availability and transport phenomena of the metals involved. In spite of the scientific efforts during the last decade, little progress has been made in unravelling the mechanisms involved in metal-ligand interactions. Using the advantages of a high specific activity (activity/quantity) radiotracer, the rate of distribution of a radiotracer over the species (free metal and metal complexes) can be followed till all the species reach the same specific activity. Due to the minute amount of mass added with the radiotracer the existing equilibria are not disturbed. With suitable chromatographic separation methods, differentiation between species is achievable. Evaluation of the time curves of the radiotracer quantity, for each species separated, gives information on the rates of exchange between the free metal and its complexes. When the species involved have reached constant specific activities the radiotracer quantity per species is directly proportional to the quantity of that species This enables calculation of stability constants. Results are presented for some radiotracer studies on the exchange of Cu2+ with Cu-complexes as occurring in natural waters and solutions of Cu-cyclam complexes. Emphasis was put on the development of separation techniques for the species involved, using both low and high pressure systems with either on- or off-line radioactivity detection. Radioactive copper (MCu2*, ti/2=12.7 h) 64 i4 was used as a radiotracer. It was produced in the IRI nuclear reactor via the Zn(nf,st,p)' Cu reaction yielding a very high specific activity product.

    -322- P6-34

    CRITICAL MICELLATION CONCENTRATIONS OF POLYVALENT METAL DIALKYLPHOSPHATES

    Golovanov V.I. Chelyabinsk Slate University

    Conductometry, surface tension measurement, turbidimetry and nephelometry, conductomet- ric and turbidimetric titrations were applied to measure the critical micellation concentration (CMC, mmol/1) of di-(2-ethylhexyl)phosphates (MXZ) and di-n-buthyl-phosphates (MBZ) in their binary aqueous solutions:

    HX NaX MpX2 CaX2 BaX2 CoX2 NiX2 CuX2 ZnX2 CdX2 FeX3 0.32 9 0.13 0.23 0.28 0.31 0.37 0.097 0.016 0.22 0.08

    NR.B CoB2 NiB2 CuB2 ZnB2 CdB2 270 67 51 67 10 57 With the use of the experimental data of some authors [1], the empiric equation has been worked out by the method of multiple regression: + IgCMC = 1.79 - 0.3Nc - 0.51- lg[Na ], (1) linking CMC with the number of carbon atoms (Nc) in the organic part of a biphyllic ion in the series of dialkylphosphates (DAP) with radicals from C4 to Cs and counter-ion concentration in the range from 0.01 to 2 mol/1. According to the pseudophase electrostatic theory (PPhET) of micellation [2] the coefficients 1.79 = A, 0.3 = B and 0.51 = Kg are the increment of a polar group, the increment of one link of a carbon chain and the parameter of a counter-ion bond re- spectively. On the basis of PPhET the equations have been put forward, enabling as a first ap- proximation to make an estimate of CMC values in the series of DAP with polyvalent cations in the absence (2) and in the presence (3) of counter ions excess: 0 lgCMC =(A/z - lgz - BNC)/(1 + Kg/z), (2) lgCMC = A/z - lgz - B-Nc - (Kg/zMM2*]. (3) For DAP with two- and threevalent cations, the equation (3) is modified as 0 IgCMC =0.47 - 0.24Nc , (4) 0 IgCMC =0.10-0.26Nc . (5) Some deviation of experimental CMC from computed values may be put down to specific interactions between counter-ion and micelle nucleus, as well as limitations of the equation (1) The equality Kg,2 = Kg,i for polyvalent and monovalent counter-ions, which has been used at the development of equations (3) and (4), is based upon the notion [3] that the effective section of a counter-ion on the micelle surface is determined by the degree of maximum closeness between ions and it is in proportion to cation charge. This important theoretical conclusion is verified by the experimental detemination of K6 for NiX2 and CdX2 at conductometric and turbidimetric titra- tion of NiSO< and CdSO< by NaX solutions. The determined values of Kg have been found equal to Kg for NaX : Kg= 0.51 (NiX2) and Kg = 0.49 (CdX2). On the basis of x-ray scattering at small angles data and light scattering data analysis, as well as explanation of kinetic patterns for electroconductiviry and light scattering isotherms the con- clusion has been reached that DAP micelles may attain dimensions in keeping with both ultrami- croheterogenous and microheterogenous dispersity. At that CMC is practically not dependent on the micelle dimensions. References: 1. Nikitin S.D., Balakhonov V.G //Radiokhimia 1992 N3. P. 165 2. Shinoda K.. et all Colloidal surfactants L.-N.-Y.: 1963 3. Golovanov V.I. //Zh. analitich Khimii 1992 V.47 N7. P. 1226

    -323- P6-35

    ELEMENT SPECIATION WITH A DUAL RADIOTRACER TECHNIQUE: "Tc IN SPINACH PLANTS

    A.V. Harms, J.T. van Elteren, H.Th. Wolterbeek, and J.J.M. de Goeij Inter/acuity Reactor Institute, Delft University of Technology, Mekehveg 15, 2629 JB DELFT, The Netherlands

    In this work an analytical speciation methodology, using two radiotracers, is presented for speciation of "Tc, a pure p"-emitter, in spinach plants. Technetium is the lightest element that has only radioactive isotopes. From an environmental point of view, the isotope "Tc is the most important one; it is one of the fission products of 23SU and B*Pu. The main sources of "Tc release to the environment are nuclear power generation and associated industry, testing programs, and to a much lesser degree, diagnostic nuclear medicine. "Tc, in the form of pertechnetate (Tc^CT), is of radioecological interest, because of its extraordinary high mobility in soil and its ability to concentrate in plants, despite being an artificial element. The results of studies performed so far on speciation of technetium in plants suggest a metabolic transformation of pertechnetate in plants to, so far unidentified, reduced technetium compounds (TcX). However, it is difficult to predict what will happen to the integrity of species due to storage, pretreatment, and the analytical method itself. Moreover, it is not always easy to follow the uptake, transformation, and emission of species in biological and environmental systems. Radiotracers may be used to trace the species and to monitor species alteration during the analytical pretreatment procedure, with a dual radiotracer both requirements can be fulfilled in one single experiment. The basic assumption is that both radiotracers should have identical properties as the species under study, i.e., the trace. The actual leaf concentration of two technetium species, i.e., "TcCV and "TcX, is determined as a function of incubation time with "TCO4 in the substrate. Addition of 9mTc04 or )9m ' Tc04 , both y-emitting species, to the substrate allows for easy radiotracing, while addition of

    -324- P6-36

    PRODUCT SPECIATION AND AQUATION AFTER THE REACTION OF 51 Cr(VI) WITH CONCENTRATED HCI AND H2SO4

    Sergio H. Pezzin, Kenneth E. Collins, Cielita Archundia* and Carol H. Collins Instiluto de Otiimica, Ihriversidade Esladual e Campinas, Cx. Postal 6154, I30H3-9~0 ('am//inas, SP, Brazil and *Institulo de ('iencias Nucleares, Universidad Nacional A utdnoma de Mexico, Ap. Postal "0-r43, 04510 Mexico, Dl\ Mexico

    Recent studies have shown that trace quantities of Cr(VI) are reduced in the presence of mineral acids such as HC1O4 and HNO3. Producing, principally, C^HiO)^'. Detailed studies of the reaction with these two acids have shown that the velocity of the reduction is increased as the concentration of the acid increases and as the concentration of the Cr(VI) decreases These results are apparently not consistent with the well-known use of acidic Cr(VI) solutions as spectrophotometric standards. The present study was undertaken to investigate the reduction of Cr(VI) in other acids, as well as to investigate the reduction products formed when complexing amons are present during the reduction process 5l For the study, high specific activity Cr(VI) was added to either 37% HCI or 98% H2SO4 and maintained under agitation at 20°C for one hour. Aliquots (100 (L) were analysed by open column catiomc (AG50Wx8, 100-200 mesh, Na* form) and amonic (AGlx8, 200-400 mesh, Cl form) either immediately or after dilution to approximately pH 2 and storage for specified time periods Stepwise elution and fraction collection, followed by counting with a Nal(Tl) detector and a single channel analyser permitted construction of elution profiles whose peaks were identified by comparison with authentic samples. When analysed immediately on the cationic column, both acids produce mainly species which elute with the initial (wash) solution, indicating the presence of anionic or neutral species For 37% HCI, a subsequent anionic exchange analysis confirms the presence of neutral species, with no residual 5lCr(VI), while significant quantities of anionic species are observed from 98% H1SO4 However, aquation at pH 2 involves substitution of the complexing anion by H2O, producing, in 3 the case of HCI, a 1+ and a 2+ species and, after 168 h, nearly 30% of Cr(H,O)f> \ The aquation of the complexes formed from reaction with H2SO4 is slower, producing about 20% each of a 1 + and a 3+ species after 168 h. These results show that trace level Cr(VI) is rapidly reduced to Cr(III) in both 37% HCI and 98% H1SO4 in the absence of conventional reducing agents and that the initial products are, 2 respectively, CrCK(H2O)i and Cr(H2O)2(SO4) ", products which undergo slow aquation at pH 2

    -325- P6-37 PHYSICO-CHEMICAL MODELLING FOR SORPTION REACTIVITY OF TRUE TRACE COLLOIDS

    Polyakov E. V., #)Egorov Yu. V., lives G. N. Institute of Solid Stale Chemistry, UD MS, Ekaterinburg 620219, Russia "Urals State Technical Vmversity-VPl, Ekaterinburg 620002, Russia

    The physico-chemical theory of state and sorption reactivity of trace elements in aqueous solutions is of great importance for understanding and monitoring radionuclide behavior in waste management processes and in the environment. One of the aspects of this problem is connected with the possibility of consequential quantitative thermodynamic description and analysis of traces distribution in heterogeneous sorption systems on the basis of mass action law. The possibility of a model of ion-exchange sorption of a hydrolyzable trace cation M" with the charge z in aqueous solution which contains its true trace colloid is discussed in this paper.

    m An equation describing pH, mass of the ion-exchanger m to "I PI volume of solution V ratio, [mi], and the initial element , ••—"\». concentration in solution, C'H dependence of the distribution g/i •$• • **V I coefficient, e=e(pH, [«], C™), has been derived from the following assumptions. The ion Mz* and hydrolysis products are in equilibrium; positively charged forms and molecules are I | reversibly adsorbed by ion-exchanger both in sub- and o 4 8 12 supersaturated solutions in which the trace true hydroxide H P colloid of the composition M(OH)2«H2Ocan exist, the phenomenon of adsorption capacity dependence of pH is negligible; the trace true hydroxide colloid exists in the equilibrium state with its ionic and molecular subsystems; the solubility product notion can be applied to the description of its real solubility; the colloid may be dissolved entirely as a result of its ionic and molecular forms adsorption on ion-exchanger under proper conditions (owing to high [m] or high ion-exchanger affinity in particular). The equation e=e(pH, [m] C'M) predicts the formation of two sharp adsorption maximums arising as a result of interposition of the true trace colloids formation by-process (pH< 6) and its dissolution (pH>l 1). The same cause should lead to a sharp leap of parameter e with variation of [mi] in the pH region of colloid formation. The general cause of the peculiarities mentioned is shown to arise from phase transition in the system "true colloid forms - molecular forms" of the trace element. The data on adsorption of trivalent iron on glass [1,2] were shown to be coincident with the equation e=e(pH) and the true trace colloid reactivity described (see Figure). The stability constants of iron complexes with the OH - ion and the solubility product for FeO(OH)soiid calculated with the help of equation e=e(pH) have been shown to be equal for both adsorption experiments [1,2].

    References [l].Bene$P., Smetana J., Majer V.: Collect. Chech. Commun. V.33, P.3410(1968). [2].Davydov Yu. P. The State of Radionuclides in Solutions (in Russian). Nauka i technika, Minsk, 1978, P. 185.

    -326- P6-38

    INTERACTION OF Sr-90 WITH SO^.HCOJ AND CO,2 IONS IN AQUEOUS SOLUTIONS OF LOW SALINITY

    Polyakov E.V., lives G.N., *}Egorov Yu.V. Institute of Solid State Chemistry, UDRAS, Ekaterinburg 620219, Russia "UralsState Technical University-UPI, Ekaterinburg 620002, Russia

    The behaviour of radiostrontium in natural ecosystems is attributed to physico-chemical forms of state of this element in liquid solutions contacting with soil [1,2]. A question of composition and stability of chemical forms existing in natural solutions of low salinity as a result of Sr interacting with principal inorganic anions of the solutions is of greet importance for correct understanding of heterogeneous adsorption processes mentioned. The results of experimental in vestigation of equilibrium in binary solutions with radiostrontium and both SO2,', CO' anions are discussed in the report. The experiments on ultrafiltration, ultracentrifugation and ion-exchange of solutions with ionic strength J<0,l mole/1 NaCl-Na2SO4, have been carried out within a wide range of the strontiumVLO2lT concentrations and showed the existence of SrSOj^ and SrfSO,,]2,^ particles below the saturation level with respect to the crystalline SiSO4cl>M,|L . The stability constants for

    these two complexes are found to be lg/?, = 2,30 ±0,20 and lg/J2 = 1,50 ±0,10 for 298 K and

    J=0. SrCI2 ion pair formation has been shown to play sufficient role in the cation-exchange equilibrium at high concentrations of chloride ions The anionic complex SrfSO,,]^ is shown to have no affinity toward common amon-exchangers. The experimental information obtained for carbonaceous system under the same conditions was shown to be in good agreement with statistical hypothesis of existence of the complexes SrHCO*,^, SrCO?^ and SnJCO,)?^ in both sub- and supersaturated solutions with respect to the SrCO, clJsnll|. In the framework of reactions Si-" + vHCO, = Sr(HCO,)2 l ,#', (1) Sr+wCO2 =Sr(CO, )J-"\/?;, (2) the stability constants for the carbonaceous complexes are found to be lg# =1,81 ±0,12 lg# <0, lg#2 = 2,25±O,O5, Ig^,2 = 2,60 + 0,10 for 298 K and ionic strength J=0,0855 NaCl - Na,CO,. It has been shown that the complex SrHCO^ does not interact with the cation-exchanger used. The sorption behaviour of trace radiostrontium carbonate colloid and the phenomenon of its spontaneous surface precipitation on heterogeneous impurities being usually present in the solution is discussed

    References [l].Benes P., Majer V. Trace Chemistry of Aqueous Solutions Prague Academia 1980.254 p. [2] Behavior of radionuclides in natural and semi-natural environments// Experimental collaboration project No5./ Editors M. Belli, F Tichomirov. EUR 1653 I EN.

    -327- P6-39

    THE IMPACT OF SPEC1ATION OF Pu ON THE DISTRIBUTION COEFFICIENTS IN A SOIL - RAINWATER SYSTEM

    Lindis Skipperud, Deborah H. Oughton and Brit Salbu Laboratory for Analytical ('hemistry. Agricultural University of Norway P.O. Box 5026, N-1432 Aas. Norway

    When radionuclides are released from a source into the terrestrial ecosystem (e.g. blow-out from Chernobyl, accidental release from Mayak PA), the assessment of long term consequences to man depends on information on the source term, transport in water and interactions with soils (KD), and uptake in food products (CF) Sensitivity analysis of assessment models demonstrates that K|j is one of the most sensitive parameters contributing to large uncertainties in the assessment. Information on the source term is usually restricted to the list of inventory and the activity levels. However, the physico-chemical forms of released radionuclides are essential for the interaction with soils and the degree of which soils will act as a sink or contaminated soils can act as a diffijse source. For multivalent elements like plutonium, releases from reactors may contain Pu included in fuel particles, Pu-colloids, oxidised forms (Puvvl), reduced forms (Puralv) or organic complexes due to interaction of Pu-species with degraded products of the protective barrier. The behaviour of Pu in the soil-water system depends on the speciation as corrosion particles and aggregating colloids may settle, while the retention of mobile Pu-species in soils may be negligible. Furthermore, the interaction of Pu-species with soils is a time and temperature dependant process. Thus, the distribution coefficient, Bq/kg soil per Bq/L water, increases with time until pseudo-equilibrium/equilibrium is reached (Ku). Thus, the contact time between contaminated rainwater and soils should be taken into account in dispersion and dose assessment models. In the present work, dynamic tracer experiments have been performed where different Pu- species are added to a soil - rainwater system (Mayak soil) to obtain Ku's for this system. After a defined contact time, the samples have been sequential extracted for determine mobile and bound fractions. For radiological assessment of radionuclides released from Mayak PA to soil - water system processes describing: source - transport - uptake in plants - biological uptake - effects must be taken into account. The distribution coefficient, KD, for Pu depends on Pu-species in question. Thus, soils act as a IIUV 11 1 VV! sink for Pu (high KD) while Pu" ' -organic and Pu should be considered more mobile (low KD) Changes in KD have an important impact on the assessment of collective dose received from a potential release of Pu from fallout, reactor accidents etc. which unlines the need for more detailed studies on speciation, kinetics and KD's in different soil - water systems.

    -328- P6-40

    INVESTIGATION OF THE INTERACTION BETWEEN ORGANIC COMPOUNDS AND URANYL IONS BY INFRARED AND RAMAN SPECTROSCOPY

    Satoru Tsushima, Shinya Nagasaki, Satoru Tanaka and Atsuyuki Suzuki Department of Quantum Engineering and Systems Science, School of Engineering, The University of Tokyo, Japan

    Uranyl ions released into the ground water interact with various organic as well as inorganic compounds. Speciation of the compound that is formed by such an interaction is quite important to predict the migration behaviour of uranyl ions in the geosphere. This paper reports on the interaction of uranyl ions with the organics that have -COO" and -OH groups. Infrared and Raman spectroscopies are very suitable tools for this purpose because these methods are based on the observations of vibrations within the target molecules. There have been virtually few work that have involved the Raman spectrum of the uranyl organic complexes. Slight changes were observed for Raman spectra of uranyl salycylate varying the ratio of the uranyl ion and the salicylic acid in the lower wavenumber bands, which are assigned to the vibration within the benzene ring. Displacement was observed for the Raman band at ~1790cm"', which are assigned to C=O stretching of-COO' group, and for the Raman band at -1380cm"1, which are assigned to OH bending vibration.

    -329- P6-41

    ISOTOPE SEPARATION AND CONTAINMENT OF 24Na IN LIGHT INDUCED DRIFT TRAP

    £. HradeCny, T. T&hal and I.M. Yermolayev Nuclear Physics Institute, 250 68 kez, Czech Republic

    We report an isotope separation of 24Na from 23Na and a containment of 24Na in a sapphire capillary with one close end using light induced drift effect. The parameters of the isotope separation are: enrichment more than 6.104, losses less than 1 %. The retention time of the 24Na atoms in the light induced drift trap was more than 100 hours.

    -330- Topic 7

    PRODUCTION AND APPLICATION OF RADIONUCLIDES

    Verbal presentations

    -331- CZ9827862

    PRODUCTION OF MEDICAL RADIOISOTOPES IN THE ORNL HIGH FLUX ISOTOPE REACTOR (HFIR) FOR CANCER TREATMENT AND ARTERIAL RESTENOSIS THERAPY AFTER PTCA

    F. F. Knapp l, Jr., A. L. Beets \ S. Mirzadeh 1, C. W. Alexander 2 and R. L. Hobbs 3 Nuclear Medicine Program ', Chemical Technology Division ^, and Research Reactor Divsion^, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN, U.S.A.

    Nuclear reactors continue to play an important role in providing medical radioisotopes for both diagnostic and therapeutic applications. Most "neutron-rich" radioisotopes are reactor- produced and often decay by beta emission. With the increasing use of beta-emitting radioisotopes in nuclear medicine, oncology and interventional cardiology, nuclear reactors will play an increasingly important role in providing radioisotopes for these applications. The High Flux Isotope Reactor (HFIR) at ORNL has a very high thermal neutron flux peaking at about 2.5 x 10'5 neutrons/cm^/sec in the central hydraulic tube (HT) position # 5. This high flux is uniquely suited for production of medical radioisotopes which have low cross sections and may require a double neutron capture such as tungsten-188. The nine hydraulic tube positions permit the insertion and removal of targets at any time during the operating cycle The new special target units currently being installed to utilize the six peripheral target positions (PTP) radially distributed in the outer target area will each house six HT target units which will significantly increase the HT target volume from the current 9 to a total of 57 units. The PTP positions are accessible only during reactor fueling and are ideally suited for production of those medical radioisotopes of current interest which require long irradiation periods such as tungsten-188 (parent of rhenium-188), tin-117m (for bone pain palliation) and -194 (parent of -194). In addition to tungsten-188, other medical radioisotopes being currently produced by the (n,y)(n,Y) double neutron capture route include -166 (parent of -166) and osmium-194 (parent of indium-194). Rhenium-186 and -177 are examples of medical radioisotopes currently produced by the simple (n,y) route which are of interest for labeling cancer therapy agents. The inelastic (nn',y) route provides higher specific activity tin- 117m and platinum-195m than produced by the usual (n,y) route Other routes which are being utilized to obtain carrier-free radioisotopes are via the (n,p) route, for example for production of scandium-47 (from titanium-47), and via the (n,y)(3 route, to provide carrier-free lutetium-177 (from ytterbium-176) and -143 (from cerium-142). Production of tungsten-188 and yttnum-90 wires is of interest for vascular therapy to inhibit restenosis after percutaneous transluminal angioplasty (PTCA) In addition, a new method involving angioplasty balloons filled with rhenium-188 available from our alumina-based generator from decay of tungsten-188 or rhenium-186 requires the dependable availability of these reactor-produced radioisotopes This paper will focus on the issues associated with the reactor production and processing of therapeutic radioisotopes from the ORNL HFIR

    Research at ORNL supported by the U.S. Department of Energy under contract DE-AC05- 96OR22464 with Lockheed Martin Energy Research Corporation.

    -332- CZ9827863

    ALTERNATIVE ROUTES FOR SUPPLY OF TECHNETIUM-99M FOR DIAGNOSTIC NUCLEAR MEDICINE

    Jeroeo J.M. de Goeij IRI, Delft University of Technology, Delft, The Netherlands

    Technetium-99 is the most frequently used radionuclide in diagnostic nuclear medicine. Although various competing non-invasive diagnostic techniques are emerging, the prospects for the next decades are still that technetium-99m remains to play an indispensable role in diagnostic medicine. However, this may only apply when the requirement of a reliable, cheap, frequent and world-wide supply of technetium-99m to hospitals is being met. This latter issue has been frequently addressed last years in publications and presentations at scientific meetings. The most widely used method for supply of technetium-99m (half-life of 6.01 h) is decay from the parent radionuclide molybdenum-99 (half-life 65.94 h) in a radionuclide generator. Nowadays most technetium-99m generators use high-specific activity molybdenum-99, which is produced in neutron-induced fission of uranium-235. Although technetium-99m generators available now generally meet customer's requirements quite well, for a number of other reasons the current methods for supply of technetium-99m to hospitals are re-evaluated and various alternatives are considered. This comprises not only modifications of the present production methods of molybdenum-99 as parent and associated generators aspects, but also exploration of totally different alternative routes, either for the production of molybdenum-99 as parent for technetium- 99m generators or for the direct production of technetium-99m. The underlying reasons for this situation are rather diverse. Quite a few are related to aspects of safety and environmental protection, e.g. proliferation of (usually highly enriched uranium-235 is used in the present method), handling and transport of large quantities of fission products (only 6% of the fissions yield molybdenum-99, the remaining is just waste), need of storage of nuclear fission waste, possible releases of radioactivity in processing irradiated targets, aging of processing units, and more generally increased legislation. Also decommissioning of nuclear research reactors reduces the availability of high flux reactors for molybdenum-99 production or as a back-up facility, and thus threatens the reliability of supply of fission molybdenum-99. The current production methods of molybdenum-99 and associated technetium-99m generators are briefly sketched, and some recent trends in the production processes are indicated Also some other possibilities for the production of fission molybdenum-99 presently considered are indicated, viz. the use of a "solution nuclear reactor" and a "spallation nuclear reactor". Alternative to the fission route, is the activation route, with various bombarding particles. In addition to the existing thermal neutron activation, now also activation with fast neutrons or with charged particles is presented as possibilities Finally, another possibility is the direct production of technetium-99 via charged-particle activation. All these routes will be presented, discussed and evaluated, in particular with respect to the prospects to meet the requirement of a reliable, cheap, frequent and world-wide supply of technetium-99m to hospitals.

    -333- CZ9827864

    DEVELOPMENT AND PRODUCTION OF 81Rb/81mKr RADIONUCLIDE GENERATOR IN NPI

    M.FiSer, P.Han£,*O.Lebeda, P.Hradilek and K.KopiCka. Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez. *Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague.

    8! 81m The cyclotron produced Rb (T,/2 = 4.58 H) and its daughter Kr (Tw= 13.3 s) constitute a radionuclide generator for nuclear medicine, being used as a common tool for ventilation and/or perfusion studies carried-out by the SPECT technique. The main advantages of this generator are good imagine properties and low radiation dose in tissue. A typical production method of 8IRb employs irradiation of pressurized Kr gas on an accelerator. The radioactive product is gained by leaching the target chamber with water. The medical Rb/Kr generator is usually designed as a cartridge containing porous solid medium loaded by radioactive Rb compound. The cartridge is connected with a carrier-gas source in a shielded unit. At a nuclear medicine department, the radioactive Kr is then eluted and administered under controlled flow conditions. Due to the short half-life of the parent 81Rb, these systems are usually manufactured and distributed near the production area. Since there exists an actual call for Rb/Kr systems in CZ, it was decided to develop an appropriate target and generator assembly in NPI. In the last year, our accelerator laboratory accomplished two new irradiation positions on the U-120M cyclotron facility. Both of them are located at the outer proton beams with the energy and intensity suitable for production of many medical radionuchdes. At the same time a new clean laboratory complex was started to build up at the accelerator building. This area will be entirely intended for the production of radiopharmaceuticals. Our current results dealing with the development of the Rb/Kr generator are presented in this paper. The Kr target is a tube drilled in a 'soft' aluminum alloy rod of checked purity. The interior of the tube is coated with a thin Ni layer and the chamber is cooled by water. The surface density of the target gas is 530 mg/cm2 of Kw, the starting pressure is 20 atm (NTP). Using this system, 0.5 Ci of 8lRb (EOB) is produced in one 5-hour's session. The Rb isotopes produced in the target are solved in water containing Rb carrier and the radioactive solution is transported by a remote system to a small hot cell in the cyclotron area. All target operations are computer controlled. The chemical yield is over 85% of total 81Rb. The final product is packed and transferred to the clean laboratory, where the generators are manufactured. The generator consists of a supported strip of ion-exchange paper, which is placed into specially designed cartridge. After wetting the strip, the Rb radioactivity is loaded on the paper by slow passing of a portion of Rb solution followed by washing. The efficiency of the Rb retention is higher than 98%. The cartridge is then dried and the generator is packed. The entire production is carried out in clean hot cells, using precise PC operated dispensers. The NPI laboratories have made the design and set-up of all devices, including the target, transport systems, dispensers and software The final generator assembly is carefully tested in accordance with the standard quality regulations. The following parameters are declared: 1. biocompatibility of the product, 2. radioactivity of 8IlnKr in the gaseous phase, 3. radio-chemical purity of the eluent and 4. tightness of the system. At present, the generator is going to be submitted to the authorities for the certification procedure.

    -334- CZ9827865

    PRODUCTION OF Ac-225 AND APPLICATION OF THE Bi-213 DAUGHTER IN CANCER THERAPY

    L. Koch, C. Apostolidis, W. Janssens, R. Molinet, J. van Geel Institute for Transuranium Elements European Commission - JRC Karlsruhe (Germany)

    There are several ongoing medical trials to use Bi-213 conjugated to monoclonal antibodies to kill tumor-cells of various cancer types. The institute is supplying Ac-225 generators for the test and is itself engaged in in-vitro cytotoxicity tests. The present supply of Ac-225 stems from Th-229 decay obtained from aged U-233. As an alternative the reaction Ra-226 (p, 2n) Ac-225 is used. The separation of Ac-225 and the conjugation of Bi-213 will be described.

    -335- CZ9827866

    THE PRODUCTION OF 211At ON THE INTERNAL CYCLOTRON BEAM AND ITS SEPARATION FROM THE TARGET FOR NUCLEAR MEDICINE PURPOSES

    O. Lebeda, M. FiSer* and P. Han£* Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague 'Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez near Prague

    211At is ct-emitter with half-life 7.214 h the physicochermcal properties of which are very promising for its perspective use in targeted cancer therapy. In spite of rather incomplete knowledge of chemistry there have been pursued many experiments with labeling of various organic carriers of 2uAt in the world laboratories. The search for suitable compound meeting all the criteria posed on an appropriate radiopharmaceutical is very intensive in last several years. Such experiments require the ""At supply in sufficient amount and nuclear purity especially with respect to 2l0Po content. We have, therefore, designed an internal beam target for 211At preparation by the most convenient 20!>Bi(a,2n)2UAt reaction on cyclotron U-120M at N.P.I, in Rez near Prague. The target was developed in collaboration with accelerator's department within N.P.I. The activities obtained are close to the theoretical values for the thick target yields under given conditions. The beam hits the target in tangential direction at small angles what reduces the necessary thickness of the Bi-layer and enables to employ an evaporation technique for its preparation. For the 211At removal from the target a quartz apparatus placed inside a ceramic oven was designed The distillation procedure is reliable, relatively fast and efficient. Astatine is collected on a quartz column filled with glass beads, and then eluted by proper agent in order to gain it in desirable chemical form. The temperature gradient in the oven during the distillation results in excellent separation of 2l<)Po from 2!lAt - the data acquired via ct-spectrometry and y-spectrometry show the ratio between 2l0Po and 211At activities to be 2xlO'10 and lower at EOB

    -336- CZ9827867

    NEUTRON IRRADIATION OF ORGANOARSENIC COMPOUNDS - A PROCEDURE FOR THE PREPARATION OF [76As]-ARSENOBETAINE

    Z. Slejkovec1"2, J.T. van Elteren2, A.R. Byrne1 and J.J.M. de Goeij2 ' Department of Environmental Sciences, Jozef Stefan Institute, Ljubljana, Slovenia 2 Inter/acuity Reactor Institute, Delft University of Technology, Delft, The Netherlands

    There is a strong emphasis on the development of arsenic speciation methods. To date, up to ten arsenic species are commonly determined in environmental matrices using hyphenated techniques comprising separation and element-specific detection. One of the most abundant arsenic species in living organisms such as e.g. marine animals and some mushrooms is arsenobetaine. The reason for this phenomenon might be a detoxification mechanism as arsenobetaine is a non-toxic compound. To study the behaviour of arsenobetaine in the food chain, especially the degradation to toxic compounds, the availability of radiolabelled arsenobetaine for use as a tracer is important. Furthermore, such a tracer would be helpful for optimisation of the analytical procedure. However, the synthesis of such a tracer is laborious and hazardous. In our previous work it was shown that neutron irradiation of organoarsenic compounds can be used to produce radiolabelled compounds based on recoil reactions according to Szilard-Chalmers principle. We elaborated on this work for the preparation of [7(1As]-arsenobetaine combining neutron irradiation with isolation procedures. Neutron irradiation of arsenobetaine or arsenocholine yields a mixture of radioactive and non-radioactive arsenic compounds which were separated using preparative ion-exchange chromatography followed by a hydride generation volatilisation procedure. The isolated [76As]-arsenobetaine was checked for its purity using high resolution high performance liquid chromatography - atomic fluorescence spectrometry. By combining these data with gamma- spectrometry data specific activities could be calculated.

    -337- CZ9827868

    PRODUCTION OF HIGH PURE 97Tc FOR ENVIRONMENTAL RESEARCH

    S.N. Dmitriev, G.V. Buklanov, T.V. Shishkina, S.V. Shishkin, G.Ya. Starodub Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research 1419H0, Dubna, Moscow Region, Russia

    The complete procedure for producing pure 97Tc is described. The reaction "Mo (4He,2n) 97Ru was used. The enriched 95Mo (>90%) target (lOmgcm'2) was irradiated with 31.5 MeV 4 97 97 He-ions for 70 h at 30 uA. Obtained Ru decays (Ti,2=2.9 d) with the formation of Tc (99.9%) and97mTc(1.7 x 10"2%). After a 100 day cooling the target was removed from the copper backing. The radiochemical procedure included dissolution of the target and subsequent distillation of 97Tc as TC2O7 with 97 HCIO4. Over 98% of Tc were recovered after two distillations. Radioactive admixtures of ?6'5758Co, MMn, 65Zn produced from the copper backing were quantitatively retained in the precipitate in the distillation flask. The obtained quantity of 97Tc was 3.5 ug. According to the calculations it contained less than 0.18 ng of 95Mo and less than 0.0036 j.ig of 97Mo.

    -338- CZ9827869

    CURIUM-244 ALPHA-SOURCES FOR SPACE STUDY

    V.M.Radchenko', B.M.Andreychikov2, G.Venke, V.D.Gavrilov1, B.N.Korchuganov2, R.Rider3, M.A.Raybinin1 and T.Ekonomoy4 'State Scientific Center Research Institute of Atomic Reactors, 433510, Dimitrovgrad, Russia 2Russian Academy of Sciences Institute of Cosmic Study, 117810, Moscow, Russia 3Max-Planck-Institute of Chemistry, 6500, Mainz, FRG ^Chicago University, 60637, Chicago, USA

    The unsealed alpha-sources was designed and prepared to furnish "Alpha-PXM" apparatus designed for analysis of Mars rock element composition and atmosphere by method of alpha back scattering, alpha-proton and X-ray fluorescence. The sources were prepared by high-temperature condensation of metal curium vapour on silicon substrates. The sources are silicon discs on which surfaces curium-244 as silicide is fixed. They have the following dimensions: disk of diameter 8 mm, active part of diameter 6 mm and 0.3 mm thickness. The sources activities are 5±1 mCi, alpha energy resolution (5.8 MeV) : 1.7-2.5% FWHM, 2.9-4.5% FWTM. Performed thermovacuum (from -196 to 1000oC), mechanical a resource tests showed the sources hold their characteristics. The sources were shown to be applied for the above mentioned analytical purposes.

    -339- CZ9827870

    PRODUCTION OF LIGHT NUCLEI FROM VARIOUS TARGETS WITH INTERMEDIATE-ENERGY BREMSSTRAHLUNG

    K. Sakamoto1, H. Matsumura2, K. Washiyama2, H. Haba2 and Y. Miyamoto2 !Department of Chemistry, Faculty of Science, and 2 Division of Physical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-11, Japan

    S. Shibata Research Reactor Institute, Kyoto University, Sennan-gun, Osaka 590-04, Japan

    M. Furukawa Faculty of Environmental and Information Science, Yokkaichi University, Yokkaichi-shi, Mie 470-01, Japan

    I. Fujiwara School of Economics, Ottemongakuin University, Ibaragi, Osaka 567, Japan

    H. Nagai and T. Kobayashi College of Humanities and Sciences, Nihon University, Tokyo 156, Japan

    K. Kobayashi Research Center for Nuclear Science and Technology, University of Tokyo, Tokyo 113, Japan

    The present work concerns the radiochemical measurements of the photonuclear reaction yields of light nuclei (7Be, 10Be, 22Na, 24Na and other heavier nuclei) from various targets over the periodic table in irradiations with bremsstrahlung beams having maximum end-point energies (Eo) up to 1200 MeV. The results were compared with proton cross sections for formation of these nuclides because it is expected that the difference of their initial steps might be reflected in the yield profiles of the fragmentation products. It would also be interesting to find some clues for distinctions whether a heavy nuclear cluster is formed as a result of emission with a certain kinetic energy (fragmentation) or as a result of many nucleon-emission (spallation residue), from an excited nucleus produced by photon irradiation. It was found that there exist direct emissions of 7Be and 24Na, as indicated by their reaction thresholds for several targets And the present results show that target mass (AJ-dependence of the yields at Eo = 1000 MeV have two components. The first component could be explained by spallation, and the second one could be explained by fragmentation. However, the extents of the relative contributions are different in different targets. The relation between the yields of light nuclei could also confirm this and those estimated by the Rudstam's empirical formula for 7 10 spallation The profile of the At-dependence of the Be and Be yields was found to be quite different, reflecting the difference of (N/Z), neutron to proton ratios, both the products and targets. Furthermore, the A,-dependence of the yields at Eo = 1000 MeV was found to be comparable in shape with the A.-dependence of the proton cross sections at Ep = 400 to 600 MeV

    -340- CZ9827871

    RECOIL STUDIES OF PHOTONUCLEAR REACTIONS ON 27AI, natCu, natAg, nalTa, AND 197Au AT INTERMEDIATE ENERGIES

    I. Fujiwara School of Economics, Otemongakuin University, Ibaragi-shi, Osaka 567, Japan

    H. Haba*, H. Matsumura*, Y. Miyamoto*, and K. Sakamoto** *Division of Physical Sciences, Graduate School of Natural Science and Technology, and **Department of Chemistry, Faculty of Science, Kanazawa University, Kanazawa-shi, Ishikawa 920-11, Japan

    Y. Oura*, S. Shibata**, M. Furukawa*** *Department of Chemistry, Faculty of Science, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-03, Japan **Research Reactor Institute, Kyoto University, Sennan-gun, Osaka 590-04, Japan ***faculty ofEnvironmental and Information Science, Yokkaichi University, Yokkaichi-shi, Mie 470-01, Japan

    We have been measured the reaction yields of bremsstrahlung-induced photopion reactions, photospallation, photofragmentation, and/or photofission from 7Li to 209Bi targets using radiochemical techniques systematically in terms of end-point energy (Eo) and target mass to investigate reaction mechanisms and nuclear structure. Nuclear recoil experiments are expected to give us additional informations related to reaction mechanisms such as angular distributions and/or kinetic energies of product nuclei. The recoil properties of 26 nuclides produced in the photonuclear reactions on "a'Cu (nat: natural isotopic abundance) at Eo of 250 to 1000 MeV have been investigated using the thick- target thick-catcher method. The two-step vector velocity model calculated kinematic properties of the product nuclei. The obtained mean ranges smoothly increase with increase of the mass difference (AA) between products and target, and show Eo-independence at Eo>6OOMeV, reflecting the limiting behaviour above (3,3) resonance region. The calculated mean kinetic energies of spallation products increase with increase of AA, showing the following three components; (1) (y,xn) products by giant-resonance and/or quasi-deuteron resonance absorptions, (2) (y,xnyp) products by mainly (3,3) resonance absorption initiated in the surface region of the nucleus (AA<15), (3) in the deep region of the nucleus (AA>15). The obtained mean kinetic energies at E0>600MeV were well reproduced by a calculation performed by PICA (Photon- Induced Intranuclear Cascade Analysis) code of Gabriel and Alsmiller at Eo=4OOMeV, except for (y,xn) products by giant-resonance, which is not included in PICA model. The recoil properties from the additional targets of 27A1, ""Ag, "alTa, and 197Au are now being measured in our group, and the preliminary results show the same trend as ""Cu. The radionuclides of Ap = 1/2-1/3 x A, are identified in the catcher foils of l97Au targets, and their recoil properties exhibit those of fission reaction, clearly distinguished from spallation reaction. These results will be discussed by referring to the previous literature values including hadron- induced reactions and to the reaction mechanism and the nuclear model on which the PICA is based.

    -341- CZ9827872

    RADIOCHEMICAL SEPARATION METHODS FOR A PREPARATION OF BIOMEDICAL CYCLOTRON RADIONUCLIDES

    N.G.Zaitseva, S.N.Dmitriev Joint Institute for Nuclear Research, Flerov Laboratory of Nuclear Reactions 141980 Dubna, Moscow region, Russia

    Different radiochemical methods (or combination of methods, eg deposition, liquid extraction, chromatography, distillation) are developed to separate the radionuclides (RNs) from irradiated target, to purify and concentrate them. The choice of methods are determined by the physico-chemical properties of target material and of the generated radioactive elements in it, on the one hand, and by the requirements for the quality of the samples (high degree of purity, carrier-free, chemical state, high specific activity), on the other. The time factor plays an important role for separation of short-lived nuclides. It is given the review of the radiochemical methods for preparation of isotopes samples of a widely or promising cyclotron-produced RNs for nuclear medicine, biomedical and environmental studies. The present data obtained in last time include the current status of the production of some gamma-emitters (97Ru, mIn, 123I, M1T1), generator-pairs ("(W'Ga, 82Sr/82Rb, 128Ba/128Cs, 178W/178Ta), radioisotopes for metabolism studies (26A1, "Cu, 237Pu) and actimdes tracers for environmental researches (a5Np, 236Np, ^'Pu). The conditions for preparation of high-purity carrier free isotopes have been investigated and procedures including target chemistry designs were developed.

    -342- CZ9827873

    RADIOTRACER STUDY OF PHOSPHATE EXCHANGE BETWEEN WHEY AND CASEIN MICELLES IN COWS MILK

    Z.I. Kolar', H.J.M. van Dijk** and T.G. Verburg" 'Department of Radiochemistry, IRI, Delft University of Technology, Mekebveg 15, 2629 JB, DELFT, The Netherlands "B. Wuytierslaan 156, 3818 LM, Amersfoort, The Netherlands

    Cow's milk contains about 30 g I'1 proteins to be divided in caseins (80%) and whey proteins. Most of the caseins occur as submicron particles, casein micelles. Micelles contain 6% inorganic matter i.e. ions such as calcium, phosphate, magnesium and citrate. These are referred to as micellar calcium phosphate (MCP) which is an essential element of the structure of casein micelles However, there is much controversy on the structure of casein micelles, the role of the MCP and its chemical form. Recently a new model for intramicellar relation of casein and MCP has been proposed. It assumes a MCP consisting of ion clusters comprising (inorganic) phosphate groups and Ca-ions (some of then may be replaced by Mg-ions). Skimmed-milk can be considered as a two-phase system of casein micelles in state of dynamic equilibrium with whey, an aqueous solution of salts and proteins. In such a system no net transport of matter between components of the system is taking place; the composition of the system is constant in time. However, there is a permanent bi-directional transport of equal amounts of matter - exchange - between various components of the system. The rate of exchange is closely related to chemical and physical processes governing this transport; a high exchange rate, for example indicates a weakly bound exchanging species. Radiotracer method has proven to be a valuable tool for studying interfacial exchange in equilibrium systems It has been applied to study exchange of calcium ions between the whey calcium salts and MCP. The present paper deals with a similar study pertaining to phosphate ions. 32 P-labelled Na2HPO4 was used as the radiotracer for inorganic phosphates of milk. After addition of the radiotracer to skimmed-milk, samples were taken regularly for 700 hours. In the samples casein micelles were separated from whey by ultracentrifugation and finally the radiotracer quantity i.e "P- concentration in the whey samples was measured using a Liquid Scintillation Counter. Compartmental analysis and modelling were used to evaluate the thus obtained time curves for radiotracer quantity in whey. This analysis revealed the presence of three phosphate compartments i.e. exchangeable phosphate entities; one being the whey phosphate. The other two are associated with the exchangeable phosphates of MCP. The mean residence times of phosphate in the latter two compartment differ considerably pointing at two distinctly different embeddings of phosphate groups in the structure of the micellar calcium phosphate of the cow's milk casein The obtained results are in fair agreement with the mentioned model of MCP.

    -343- CZ9827874

    APPLICATION OF RADIOACTIVE ANIONS FOR DETERMINATION OF POLYNUCLEAR COMPLEXES CHARGE

    Davydov D.Yu., Prokshin N.E., Zabrodsky V.N.,Toropov I.G., Davydov Yu.P.

    At present, there are a lot of works dedicated to the formation, due to the hydrolysis process, of polynuclear complexes of multicharged metal ions in aqueous solution. However, a few of them propose reliable methods for determination of composition of the polynuclear complexes and their charge. Hence many unsertainties about the latter are derived. In this work the method for determination of polynuclear complexes charge is proposed. This method is based on the fact that the positive polynuclear complexes of metal ions may join negativly charged complexing anions, which will neutralize them. Thus, knowing the quantity of anion necessary for full neutralization and its charge, one can calculate the charge of initial polynuclear complex. The dialysis through semipermiable cellophane membrane was used for determination of quantity of anion joined with the polynuclear complex since such anions can not penetrate through the membrane. The radioactive isotopes of sulfer, phosphorus and iodine were correspondingly used for measurement of SO42", PO43" and I" anions concentrations. 2 3 The interaction of SO4 ', PO4 " and I' anions with the iron (III) polynuclear complexes was investigated by dialysis method. The phosphate anion was chosen for determination of the polynuclear complex charge. On the basis of data obtained the charge of the iron(III) polynuclear complex has been calculated.

    -344- CZ9827875

    MEASURING THE DIFFUSION AND SORPTION OF TRACE ELEMENTS AND RADIONUCLIDES IN SOILS, CLAYS AND BENTONITES

    Alexandr Gosman, Irena Hvoid'ova and J.L.Martinez Nieto Katedrajademe chemie FJFICVUT, Bfehovd 7, 115 19 Praha 1

    The advanced communication discusses the proposed capillary modification of the method of measuring trace elements and radionuclides dtffusivity in soils, clays and bentonites. The method is based on the diffusion from an infinitively (very) thin labelled layer (paper disc) through a very thick layer of the given moist material in a glass capillary (length ~ 2 cm, inner diameter ~ 0,5 cm) hermetically closed at both sides, on the consecutive sectioning of thin layers of the material pressed out of the capillary after the diffusion, and on measuring their specific activities. The effective diffusion coefficient Da values (for 137Cs, 85Sr, 65Zn) were calculated by using equation a = ao exp(-x2/4Dtf t)/( pD^ t)"2, being the solution of Fick's 2°d law at the given conditions of the moist adsorbing medium. In this equation a stands for specific activity of the layer removed at the distance x from the origin of co-ordinates, ao - initial specific activity (in the infinite - very thin layer) in the origin of co-ordinates, t - total diffusion time. For evaluation and application of the Dcf values (e.g., for prediction of the difrusivity) there were used their dependences on moisture, distribution coefficients Kj of the given nuclides, sizes of the given material particles, and pH of the medium. Also some relations were applied from the literature data for theoretical values of the diffusion coefficients and compared with the data measured. The findings of the diffusivity studied are the following: the validity of Fick s laws in the given media; increasing of Drf and Kj with increasing moisture; for soil (Lesni potok, Central Bohemia, locality of levany, £R) sample with particle dimensions < 0,047 cm the values of D^'^Cs) are by one order of the magnitude lower than for a sample with particle dimensions < 0,08 cm; sorption of 137Cs is substantially greater than for 85Sr and Dd(85Sr) was several times greater than 137 137 85 137 Dci( Cs); Dcf( Cs) < D^'Zn) < Def( Sr) which corresponded with K,, values, i.e. K,,( Cs) » 10 times greater than Kj(65Zn) and Kj(85Sr), which are of the same order. Of importance was the comparison of difrusivity data at near moistures in soil and clay (clay - Northern Bohemia 99 - overbed, Sokolov, CR): Def values in clay are by one order of magnitude lower than in soil. There was also studied - both in soil and bentonite (bentonite Sabenyl, source Keramo, Obrnice £R) - the possible influence of the prediffusion rest time t, prior to the diffusion on establishing physico-chemical equilibrium in the material hermetically closed in the capillary Besides t,, the study also concentrated on the influence of shaking time in the closed vessel; after the chosen time t, the material was placed into the capillary (than the diffusion started) For 85 example, it has been found for active bentonite that for t, = 2 days and 7 days the Dci( Sr) and B7 Def( Cs) increased 6.88 times and 2.07 times, respectively. In the soil it has been observed that 65 137 the De(( Zn) and Dej{ Cs) values increased -1.2 and 1.3 times for t, = 1 day compared with t, = 1 day, respectively. Greater increase has been seen in active bentonite~3.0 and 2.8 times for 8S Dci( Sr) and DeX^Zn) at t, = 6 days compared with t, = 1 day, respectively At the same time m Dc,< Cs) decreased ~ 1.4 times The method described enables an easy procedure and relatively short time for measuring the diffusivity in small volumes of the given media

    NEXT f -345- ieft BLANK Topic 7

    PRODUCTION AND APPLICATION OF RADIONUCLIDES

    Poster presentations

    -347- P7-1

    MEASUREMENT OF SODIUM-22 CHLORIDE TRACER DIFFUSION 22 COEFFICIENT IN THE SYSTEM H2O + NaCI + MgCI2 AT 25 °C

    Jori Ahl and Si mo Liukkonen Helsinki University of Technology, Department of Physical Chemistry and Electrochemistry, P.O.Box 6100, HN-02015 HUT, Finland

    Sodium-22 tracer diffusion coefficients were determined in aqueous solution of magnesium chloride by applying the closed capillary method. The measurements were made in large con- centration region 0.1 mol dm"1 the base electrolyte MgCli. In the method the quartz capillary was filled one half with radioactive solution (22NaCl + in MgCb, aq) and second half with inactive solution (MgCb,aq). The closed capillary was located vertically above the scintillating detector of plane type. The position of the capillary relative to the detector determines the total number of counts registered in gamma-counting or the intensity I(t). The concentration distribution c(x,t) found as solution of Fick's second law is multiplied with decay constant of 22Na and with the counting probability r(x) Their product is integrated over the lenght of capillary. A time dependent I(t) is then found in the form of an infinite serie. The one term solution in the serie is valid after about 20 h from the beginning of experiments. Using experimental data the slope of the linear dependence: In [I(t) - l(t= 4)] = -(D Si2/L2)t + constant.; is determined and the tracer D-value is calculated from it. However, to find the most exact value to diffusion coefficient the following method was applied. The value of the equilibrium intensity I(t=4) was first determined with the multilinear regression analysis. This value was then used in the linear regression to calculate the slope. 3 For the concentration range of 0 01 .0.0005 mol dm' of MgCl2 the tracer diffusion coefficient was shown to follow the Onsager limiting law. The limiting value of D4(22NaCl, aq) was determined by extrapolating measured tracer D(22NaCl) values as function of the square root of MgCb concentration to the infinite dilution The extrapolated D4(22NaCl) was 1.334A10'5 cm2 s1 corresponding to the Nernst limiting value calculated from the molar conductivity of sodium ion at infinite dilution The experimental arrangements applied here do not require the preparation of a very sharp boundary between the two capillary solutions (active and inactive) in the beginning of an experiment. This is due to the nature of the partial differential equation basing on Fick's second law. It is not an initial value problem but instead a boundary value problem. The accuracy of the determination of tracer diffusion coefficient was estimated with error analysis to be in average ± O.OO3A1O"5 cm2 s'1.

    -348- P7-2

    CALIFORNIUM-252 FISSION FRAGMENTS SOURCES

    N.N.Andreychuk, A.Yu.Baranov, V.D.Gavrilov, L.S.Lebedeva, V.M.Radchenko, M.A.Ryabinin, and I.V.Tselischev SSC RF Research Institute of Atomic Reactors 433510, Dimitrovgrad-10, Ulyanovsk region, Russia

    A description is given for preparation of fission fragment sources by means of caIifornium-252 hydroxide electrochemical deposition on platinum substrate followed by hydrogen reduction at 1200°C. The spectrometric devices for monitoring energy spectrum, alpha-particle flux intensity and fission fragments are described. When using bimetallic substrates (X18H10T steel + Pt), the sources were obtained with energy resolution less than 2% and activity up to 20 MBq. The technique of californium-252 oxide application on thin carbon film (5 u,g/cm2) is considered. As it was calculated and proved in experiments under chosen conditions and vaporization geometry about 2% of initial preparation amount was condensed on the substrate. The sources were prepared of activity about 6-7 kBq.

    -349- P7-3

    ISOTOPE EXCHANGE OF STRONTIUM AND MOLYBDATE IONS IN STRONTIUM POLYMOLYBDATES

    Giilten Atun* and Nazan Bodur** * /. UMUhendislik Fakultesi Kimya Bolumti, TURKEY ** Cekmece Niikleer Research and Training Centre, TURKEY

    The heterogeneous isotopic exchange reactions between strontium polymolybdates, Sr2tand MoO/ ions in the strontium nitrate and sodium molybdate solutions have been studied using Sr-90 and Mo-99 as tracers. Electrometric methods have been used to study the compositions of strontium molybdates obtained by adding strontium chloride to progressively acidified solution of sodium molybdate. It has been found that the chain length of strontium polymolybdates increases by decreasing the pH of the media. Exchange equilibrium constant K has been calculated between 298 K and 348 K as well as AG, AH and AS. The results indicate that Sr2* cations have much higher affinity for exchangers than MOO4" anions. By fitting of the data to the Dubinin-Radushkevich (D-R) isotherm were showed that the total exchange for both ions is affected by ion adsorption process at low temperatures and by ion exchange process at high temperatures. At high concentrations, recrystallization process contributes the cation exchange while ineffective for the anion exchange.

    -350- P7-4

    GETTING MICROSPHERE THORIUM DIOXIDE

    Balakhonov V.G., Matyukha V.A., Saltan N.P. Siberian Group of Chemical Enterprises, I Kurchatov St., Seversk, 636070, Tomsk region, Russia.

    Filippov E.A., Zhiganov A.N., Seversk Technological Institute, 65 Communist Avenue, Seversk, 636070, Tomsk region, Russia.

    There has been proposed the method for getting granulated thorium dioxide from the solu- tions of its salts according to the cryogenic technology by the method of solid-phase conversion. It contains the following operations: dispersing of initial solution into liquid nitrogen and getting cryograins of necessary sizes by putting oscillations of definite frequency on a draw plate and charging formed drops in a constant electric field, solid-phase conversion of thorium salts into its hydroxide by processing cryograins with cooled ammonia solution, drying and calcination of hy- droxide grains getting granulated thorium dioxide. At the pilot facility there have been defined conditions and developed optimal regime for get- ting thorium dioxide. The mechanism of converting thorium dioxide cryograins into thorium diox- ide was investigated by methods of thermal analysis.

    -351- P7-5

    RADIOKINETIC STUDY ON THE NUCLEATION, IN AGAR AND GELATIN, OF SOME CRYSTALS CONTAINING 55+59Fe3+ IONS

    Al. Cecal, Sorina Chisca and M. Palamaru Faculty of Chemistry, Al.I.Cuza University, Copou Street-11, 6600-Iasi, Romania

    The paper presents a radiokinetic study on the appearance and growth of *Fe2S3, *Fe(OH)3, *Fe2(C2O4)3, *Fe(IO3)3 crystals in colloidal medium of agar and gelatin. The values of the constants of diffusion through gel of 55*!9Fe3* radioactive cations and of the rate of global growth process of these crystals in agar or gelatin were calculated using experimental data. A new method for the determination of the starting time for the complex nucleation process was proposed. The formation rate of the crystals under study decreases in the order: *Fe(OH)3 > *Fe(IO3)3 > *Fe2S3 > Fe2(Cr04)3, creasing the starting time of nucle^ation.

    -352- P7-6

    SYNTHESIS AND BIODISTRIBUTION OF SOME TECHNETIUM - PHOSPHONIC ACID COMPLEXES AS POTENTIAL BONE SCINTIGRAPHY AGENTS

    J. Doubsky1, A. LiznKkovi2, M. LiznKek2, L. LeSeticky1 Department of Organic Chemistry, Charles University, Praha 2Department of Pharmacology and Toxicilogy, Charles University, Hradec Kralove

    The aim of this study was to prepare and evaluate the potential bone scintigraphy agents having in molecule both methylenphosphonic and iminoacetic groups. Different ratio of phosphonic and carboxylic group in the molecule should change the biodistribution patterns.

    Synthesis of ligands The following ligands have been synthesised: nitrilotris(methylenphosphonic) acid, NTPM (I); N-phosphonomethyl) iminodiacetic acid, PMIDA (II); N,N-bis(phosphonomethyl glycin, (DMPG) (III); N-(2-phosphonoethyl) iminodiacetic acid (PEIDA) (IV); 3-carboxy- 3-(N-carboxymethyl-arninomethyl)-l,5-pentanediphosphonic acid (V). All compounds were tested for purity and identity by means of TLC, H and C NMR spectroscopy and FAB MS

    X I. X=Y=Z=PO3H2 ^ CQOH

    II. X=Y=COOH,Z=PQ3H2 "2-j.v m -Nx. III. X=Y=POiH2, ZFCOOH

    IV X=Y=COOH, Z=CH2PO3H2

    Synthesis of complexes The optimisation of preparative procedures (pH, molar ratio of reagents) has been done with long living "Tc. The pH change has probably influence on the structure of complex formed and also on technetium oxidation number. The molecular structure of the complexes has not been estimated yet. The complexes of '"Tc were prepared according to standard procedure with SnCl2 as reducing agent. The radiochemical purity was determined by usual way (ITLC-SG with acetone and 0. \ 5 M NaCl as eluents) being better than 95 %.

    Biodistribution All complexes had the similar distribution in the animal (rattus norvegicus) organism with exception of bones and kidneys. The complexes with two or more phosphonic groups in molecule had higher cumulation of radioactivity in bones whereas the complexes with only one phosphonic group showed higher radioactivity in kidneys. Even though the complexes with at least two phosphonic groups showed remarkable accumulation in the bone tissue, is that amount lower than at ™Tc-methylendiphosphonate and mTc-diethylentnaminopentamethylenphos-phonate (com- plexes clinically used for diagnostics of bone metastases)

    -353- P7-7

    SYNTHESIS OF RADIOLABELLED ORGANIC COMPOUNDS FOR USE AS WATER TRACERS IN OIL RESERVOIRS

    D.0. Eriksen and V. Bjernstad1 Institute for Energy Technology, P.O.BOX 40, N-2007 Kjeller, Norway 'Present address: Department of Chemistry, University of Oslo, P.O.BOX 1033, Blindern, N-0315 Oslo, Norway

    Injection of water into oil-bearing strata to maintain field pressure is usually the primary choice to enhance oil-recovery. Each production well may thus be surrounded by several injection wells. However, fluids from each injection well may reach more than one production well, depending on the topography. To achieve the optimum field performance, there is a need for means to determine the flow pattern of water in the reservoir. The best method of obtaining this information is to add compounds to trace the injected water and measure them in the produced water phase. In addition to knowledge of flow-velocities in the reservoir, by simulations of the tracer-pulse response one may deduce other important information, e.g. permeability, stratification, channelling and flow-barriers, within the reservoir. Thus, use of tracer methods is part of the oil companies' basis for making economical decisions. Such water tracing requires passive tracers, i.e. compounds that behave exactly like the substance studied under the conditions of interest. This implies that a water-tracer in a water- flooded oil-field must fulfil requirements like no absorption to reservoir rock, no partitioning (or distribution) with respect to the other fluids present, long time thermal stability, microbial resistance and high detectability. In addition, the tracer compound has to be environmentally acceptable and available at a reasonable cost. An extensive number of compounds have been laboratory tested according to these criteria. Among these are therephthalic acid, isophtalic acid and trimesic acid. We report the most important experimental results for radiolabelling these compounds in order to achieve ultra-low detection limits for field use. The acids are labelled with 14C. The work has been supported in part by the Norwegian Research Council and the following oil-companies: Amerada Hess, BP Exploration, Conoco, Mobil, Petrobras, Phillips Petroleum Co. Norway, Saga Petroleum and Statoil through ITRC - IFE Tracer Research Co- operation.

    -354- P7-8

    EXTRACTION OF RHENIUM-188 FROM ZIRCONIUM AND ALUMINIUM TUNGSTATES CONTAINING TUNGSTEN-188

    S.V. Ermolaev, M.V. Lukianenko, L.A. Smakhtin Obninsk Branch Karpov Institute of Physical Chemistry

    188Re is a perspective radionuclide for using in nuclear medicine as a therapeutic agent. It is attractive neither its nuclear characteristics (£p «2MeV, £, = 155 keV(15%), Tin =16.9 hours) nor the opportunity of its production by means of a generator in which the decay reaction occurs: 188 I88 W( Tm= 69.4 days)-> Re. Generally the generators of two types are investigated: sorption generators based on AI2O3 and gel generators with an insoluble salt of tungsten as a matrix of a chromatographic column Performance of the both generators is the same and the main difference is that the tungsten fraction per gram of the gel generator matrix is approximately ten times higher than in case of the sorption one. It is essential when we have to use tungsten compositions with a low specific activity of 188W. This paper presents some results of research of zirconium and aluminum tungstates. They were obtained by precipitation from a solution (/ = 65 -s- 70 °C):

    l88 188 MeXn + |Na2W[ W]O4 = Me (W[ W]O4)n^4- + nNaX (1),

    where X= Cl.", NO,". Previously a sodium tungstate solution was titrated by HC1. We distinguished the pH intervals of preferable existence of different kinds of tungstates: pH=8+10 normal tungstate Na2WO4 pH=6*7 para-tungstate pH=3*5 meta-tungstate We found out that the more large-dispersed precipitates were obtained when we took in the reaction (1) a sodium para-tungstate solution. It was important for further extraction of I8SRe, which was carried out by means of a hermetically sealed vial and a syringe on the scheme, injecting an eluant into the vial - suspending - centrifuging - sucking out an eluate. The 0.9% NaCl solution was the eluant. We obtained the average values of 188Re extraction efficiency: 75% in case of zirconium tungstate, 60% - aluminum tungstate. L88Re was present in the eluates in the form of perrhenate ReOj. Tungsten concentration of the eluates measured by colonmetric and spectrum emission techniques was within 10-50 // g/ml for the both tungstates.

    -355- P7-9

    UNIT OPERATIONS MATHEMATICAL SIMULATION IN A "Mo PRODUCTION PROCESS FOR MEDICAL PURPOSES

    M.A. Goncalves, A.R.L. Nery, M. Yamaura, M.C.F.C. Felinto, R.L. Camilo, V.H. Cohen Institute) de Pesquisas Energeticas e Nucleares Travessa R, 400 Cidade Universitaria 05508-900 Sao Paulo SP Brazil

    This work deals with the mathematical modeling of the unit operations process to obtain "Mo from the U3S12, low enriched uranium targets, being ""Tc from "Mo decay the most employed radionuclide in the nuclear medicine. Targets were dissolved in two steps being the first dissolution of the aluminum cladding by using a KOH solution. Temperature influence on the reaction rate and the dissolution reaction order were determined for these experiments. Ion exchange operations for the "Mo purification were studied in order to obtain adsorption equilibrium isotherms, breakthrough and elution curves. For the first purification column, which is filled with AG1X8 resin, experiments were accomplished by varying the molybdenum concentrations from 1 mg/L to 10 g/L in KOH media at room temperature, 40°C and 60°C. Langmuir and Freundlich isotherms models could be adopted to fit the obtained adsorption equilibrium isotherms data. Mass transfer coefficients were obtained from column experiments in order to solve the mass balance differential equations describing the breakthrough curves.

    -356- P7-10

    NUCLEAR-CHEMICAL METHODS OF THE HARD TOOTH TISSUE ABRASION STUDY

    A. Gosman", D. HouSovâ", £. Jechc, J. Kontfek" and L. Dolezalovâ" "Katedrajademè chemie FJFICVUT, Bfebovà 7, 115 19 Praha 1 bVyzkumny ùstav stomatologicky, Vinohradskà 48, 120 60 Praha 2 'Ûstavfyzikàlnichemie JaroslavaHeyrovského AVCR, Doleßkova 3, 182 23Praha8 dKatedrajyziky FJFI CVUT, Bfehovâ 7, 115 19 Praha l

    The advanced method consists in implantation - labelling of the thin surface layers of the solid objects, e.g. hard tooth tissue, by atoms of suitable natural or artificial radionuclides. Nuclides from the uranium series were implanted into the surface by using nuclear recoil effect at alpha decay of 226Ra to 222Rn, alpha decay of 222Rn to RaA, alpha decay of RaA to RaB (beta-emitter) and further alpha or beta emitters. With regard to the chosen alpha detection and to the half-lives of the radionuclides, there was actually measured the activity of 222Rn, RaA and RaC in the thin surface layer. The implantation was realized as a "vacuum implantation": the thm 226Ra source and the hard tooth tissue (together with Al-foil used after irradiation for standardizing the measured activities) were placed close together in a vessel evacuated for the time required for irradiation (4 hours) After irradiation the surfaces of the tissue and Al-foil were measured. The laboratory simulation of the abrasion followed this in the system of "toothbrush - various suspensions of the tooth-pastes - hard tooth tissue (or material standard - ivory)" in a specially designed device - the dentoabrasionmeter. The activities of the tissue surface measured before and after abrasion were used for calculations of the relative drop of the surface activity. On this basis the influence of various tooth-pastes containing various abrasive substances was determined, e.g., tooth-pastes of the carbonate type have shown higher abrasion than the tooth-pastes of the phosphate type. Besides the procedure described, also the method of electrostatic deposition of the thoron daughter ThA atoms on the negatively charged surface was designed and experimentally verified. In this method the atoms of ThB (originated by alpha decay of ThA) are recoil-injected into the surface layer. In more detail this procedure is described in another paper presented at this conference (C.Jech) as a part of a more detailed study of surface labelling.

    This research has been supported by Grant Agency of the CR, grant No. 106/96/0 76.

    -357- P7-11

    PREPARATION OF RADIOACTIVE "Ti TARGET

    P. Han£, M. FiSer, M. Honusek Nuclear Physics Institute ofAcad Sci. of the Czech Republic 250 68 Rez near Prague, Czech Republic

    Up to now, the fragmentation reaction was used to produce 100Sn [1]. The radioactive target out of 44Ti (Tin = 47,3 y) could open new possibilities to produce and study '00Sn nucleus and other rare nuclei using the fusion reaction with the stable beam of ions like 64Zn or 58Ni. The reaction yield is given by the cross-section of «1016 /J> and the number of 44Ti atoms in the target. **ri activity was prepared using reaction 4SSc(p,2n) at the parasitic beam of our cyclotron U-120M with proton energy of 20 - 25 MeV. The irradiated Sc foil was dissolved in 4 M HC1, when H2O2 was added at the end reaction [2]. The experimental conditions for a reproducible high yield extraction in range concentration HC1 (0,5 - 4 M) have been investigated. The operation of removing traces of Sc by ion chromatography in range concentration HC1 (0,5 -AM) has been investigated. The experimental conditions for a reproducible high yield electrodeposition of titanium in the Hg range have been investigated. A plating cell for the use of tantalum microfoil as backing was designed, so that the target production of rare titanium isotopes became possible with high efficiency. The optimum method of the preparation of radioactive 41Ti targets was described:

    1 Dissolving of Sc foil in 4 M HC1 with 1% H2O2. 2. Twofold extraction of the Sc bulk with 1% H2O2[2]. 3. Removing traces of Sc by ion chromatography - Ti elution with 2 M HCI containing 1% H2O2 4. Conversion 44Ti solution to a nitrate. 5. Preparation of 44Ti target by an electrolytic „ molecular plating,,[3]

    References

    [1] Rykaczewski K. et al., Phys.Rev. C52 (1995) R2310 [2] Frekers D et al., Phys.Rev. C28 (1983) 1756 [3]Grzonka et al., Nucl.Instr.Meth A250 (1986) 573

    -358- P7-12

    252Cf SPECTRUM-AVERAGED CROSS SECTION FOR THE 63Cu(n,p)63Ni REACTION

    M. Imamura,* T. Shibata, S. Shibata,** T. Ohkubo and S. Satoh Institute for Nuclear Study, University of Tokyo, Tanashi, Tokyo 188, Japan

    N. Nogawa Radioisotope Centre, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan

    We have measured activation cross sections of the 63Cu(n,p)63Ni reaction averaged for the neutron spectrum from 252Cf . The measurement was performed to study the 63Ni production in copper samples irradiated by the Hiroshima atomic bomb and to investigate the fast neutron fluence at MeV region, a possible clue to elucidate the source of discrepancy between the derived neutron spectrum for the Hiroshima atomic bomb and the spectrum calculated in the Dosimetry System 1986, DS86 [1,2]. The Cf source was placed in the center of a spherical copper shell (inner diameter of 60 mm and thickness of 3 mm), which consisted of two half shells. The source of neutron intensity was calibrated to be (6.87 ± 0.17) oo 106 n/sec using the monitor reaction of mIn(n,n')u5mIn (a = 196 ± 4 mb). After irradiation, the copper shells were dissolved in dilute acids (H2SO4 + HNO3) with known amounts of nickel (~ 1 mg) carriers. Most of the copper was removed by electrodeposition and the remaining solution was chemically processed through precipitation from a NaOH solution and an anion exchange separation. The radioactivity of 63Ni was determined by liquid-scintillation counting. The obtained cross section for the 63Cu(n,p)63Ni reaction was 20.0 ± 0.8 mb, slightly lower than the calculated value of 25.7 mb using the 252Cf neutron-spectrum and the calculated cross section for the 63Cu(n,p)63Ni reaction given in JENDL-3 [3]

    References [1] US-Japan Joint Reassessment of Atomic Bomb Radiation Dosimetry in Hiroshima and Nagasaki, Final Report Radiation Effects Research Foundation, ed. W C. Roesh (1987) Vols. 1 and 2. [2] T. Shibata et al., J. Phys. Soc. Jpn., 63 (1994) 3546. [3] K. Shibata et al., Japanese Evaluated Nucl. Data Library, Version-3, (JENDL-3) JAERI 1319(1990).

    *Present address: National Museum of Japanese History, Sakura, Chiba 285, Japan **Present address: Research Reactor Institute, Kyoto University, Sennan, Osaka 590-04, Japan

    -359- P7-13

    NEUTRON SOURCES: PRODUCTION AND WAYS OF TECHNOLOGY IMPROVEMENT

    E.A.Karelin, V.I.Karasev, V.M.Radchenko, V.A.Makarenko, E.V.Shimbarev, M.A.Ryabinin, L.S.Lebedeva, V.D.Gavrilov, V.M.Vituytnev, and N.N.Andreychuk State Scientific Center of Russian Federation Research Institute of Atomic Reactors 433510, Dimitrovgrad-IO, Ulyanovsk region, Russia

    Information is presented about Californium-252 neutron sources produced at SSC RF RIAR. Methods are proposed to improve quality of source active core and to increase their ecological safety: alumochromophosphate application onto foam-alundum core; preparation of active core as californium oxide cermet or californium alloy with platinum metals. When preparing simulators and experimental lot of sources, the advantage of proposed methods have been shown. To monitor neutron flux while producing sources reference curium-248 neutron radiation source has been prepared; curium-248 has longer half-life period compared with californium-252, such as 3.6105 years. Active core of this source is a pellet made of platinum alloy with curium.

    -360- P7-14

    TRITIATION OF DELTA-RECEPTOR SELECTIVE ANTAGONIST DIPEPTIDE LIGANDS CONTAINING 2\&- DIMETHYL-TYROSINE

    I. Kertesz, S. Salvadoria, G. Balboni", R. Guerrini", A. Borsodi, G. T6th Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, P.O.B.521, H-6701, Szeged, Hungary "• Department of Pharmaceutical Sciences and Biotechnology Center, University ofFerrara, Ferrara 44100, Italy

    To enhance 5 antagonist interaction at opioid receptors, new antagonists were developed by substitution of 2',6'-dimethyl-L-Tyrosine (Dmt) for Tyr1 in Tyr-Tic peptides (l,2,3,4,-tetrahydroisoquinoline-3-carboxilic acid (Tic))"1. Two new analogues (H-Dmt-Tic-OH and N,N(Me)2Dmt-Tic-0H) with high affinity and selectivity were chosen for tntiation. H-Dmt-Tic-OH and N,N(Me)2Dmt-Tic-0H were prepared by solid-phase peptid synthesis Diiodinated precursors were made by chloramine T method. [3H]Dmt-Tic-OH and 3 3 N,N(Me)2[ H]Dmt-Tic-OH were prepared by catalytic dehalogenation of the precursors using H2 gas, Pd/BaSO4 and triethylamine in DMF. The crude tritiated peptides were purified by RP- HPLC. Purity control: analytical RP-HPLC and TLC. The specific activity of the tritiated peptides was 1.27TBq/mmol (34.22 Ci/mmol) for [3H]Dmt-Tic-OH and it was 2.22 TBq/mmol 3 (59.88 Ci/mmol) for N,N(Me)2[ H]Dmt-Tic-OH. The stability of the tntiated peptides was investigated in storage condition and in rat brain membrane binding assay condition. The [3H]Dmt-Tic-OH can produce diketopiperazine, while the N-methylated analogue is more stable in these experiments and it looks useful tool for receptor binding assay.

    References 1 Salvador], S., Attila, M, Balboni, G, Bianchi, C, Bryant, S D., Crescenzi, O., Guernni, R, Picone, D., Tancredi, T., Temussi, P. A. and Lazarus, L H., 6 Opioidmimetic Antagonists: Prototypes for Designing a New Generation of Ultraselective Opioid Peptides Mol. Med.,1, pp 678-689, (1995)

    -361- P7-15

    RADIOANALYTICAL METHODS FOR ESTIMATION OF SALTS SOLUBILITY

    A.P. Krasnopyorova Research Institute for Chemistry of Kharkov State University 4, Svoboaysq., 310077, Kharkov, Ukraine

    The solubility estimation is the problem of the great theoretical and practical interest. The data on solubility are necessary in developing chemical current sources, for isolation and separation of chemical elements by means of co- and re-precipitation at all work stages of the nuclear fuel cycle. There is a great number of methods which allow to determine the substance solubility. The common ones are gravimetry, photometry, conductometry, potentiometry, polarography, etc However, the every of them has its own shortcomings restricting its practical application. Recently, the radioanalytical methods (namely, radioactive indicators, activation and X-ray fluorescent techniques) are increasingly used for the solubility determinations. The application of these methods is based on the direct relationship between the quantity of the radioactive or «marked» substance and the intensity of its radiation. The radioactivity as the analytical characteristics of the substance has its particular advantages compared to the analytical properties used in another analytical techniques. The accuracy of the radiometric measurements is defined mainly by instrumental errors lying within the limits of 2%. By virtue of this, high sensitivity, selectivity and expressness are provided. From radioanalytical methods listed above, the radioactive indicators techniques is in most wide use for solubility determinations. The method first proposed in 1913 by Hevesy and Paneth for the estimation of lead salts solubility retains its attractivity to date The solubility determination by means of the radioactive indicators may be realised in different ways: 1) the isotopic radioactive indicators (direct method, mostly used); 2) the isomorphic indicators; 3) the isotope dilution method; 4) Neuman's method; 5) radiometric titration The main advantages of the radioactive indicators technique are as follows: • the high sensitivity of trace quantities detection enables us to determine solubilities of the extremely low- soluble compounds, • the method is appeared to be of general purpose due to the existence of the radioactive isotopes for almost all the elements of the periodic system, • the elements dose in their properties to the determined one do not interfere as a rule; • the measurements is possible even though alien agents ( e.g., salt dopants complexing agents, coarse impurities) are present, • the experimental procedure is highly simple and rapid that enables its automatisation in serial determinations, • the general content is available for the element or compound of interest in the solutions of any composition The author applying the direct method (1) has investigated the solubility of the number of compounds in different solvents within the wide temperature range. The isotopes of "~Na, 6C1; 4" Ca, Rb, Sr; Ag; ' Cs were used as radioactive indicators.

    -362- P7-16

    AMERICIUM-243 BASED SOURCES

    L.S.Lebedeva, A.Yu.Baranov, V.M.Radchenko, and M.A.Ryabinin SSC RF Research Institute of Atomic Reactors 433510, Dimitrovgrad-IO, Ulyanovsk region, Russia

    Technology was developed for americium-243 electrochemical deposition on flat nickel substrate from aqueous-alcoholic electrolyte based on isobutyl alcohol. The process operations and cartogram of americium distribution on the substrate are given. Due to influence of the edge effects the amount of material to be deposited on the boundary of active spot is increased that determines essentially the value of americium distribution non-uniformity. Methods of activity determination and americium distribution uniformity are described. To improve the adhesion between the deposit and the substrate material and its transfer it into oxide form the sources were annealed in the atmosphere of gaseous mixture (5%H2+He) at 800°C. The technology allows preparing unsealed sources of ionising radiation based on TPE oxides with radionuclide surface density up to 0.3 mg/cm2, active spot diameter up to 35 mm and distribution nonuniformity up to 20%.

    -363- P7-17

    FIRST EXPERIENCES WITH PRODUCTION AND QUALITY CONTROL OF 2-DEOXY-2-[18F]-FLUORO-D-GLUCOSE IN NUCLEAR PHYSICS INSTITUTE, ACADEMY OF SCIENCES OF THE CZECH REPUBLIC

    Melichar F., Kropa£ek M., Svihla P., Stursa J., KuCera J., Lacman J. Nuclear Physics Institute Academy of Sciences of the Czech Republic, lUiZ 250 6H

    Preparation of fluorine-18 occurred by the reaction 1SO (p, n) 1SF on the cyclotron U 120 M with 17 MeV protons. Enriched 18O water, as target water is used. Synthesis of 2-deoxy-2-[l8F]- fluoro-D-glucose (2-[18F] FDG) is carried out in the PET Trace FDG MicroLab automatic machine This equipment applies the method derived from Mulholland et al (Mulholland et al, Nucl Med. Biol (1990) 17 (3) 273-9), which used solid-phase trapping of the I8F" anion on a resin and the subsequent reaction of this anion with a 2-[18F] FDG precursor (mannose trifiate) Radionuclide, radiochemical, and chemical purity of produced 2-['8F] FDG is controlled, as well as pH, total and specific activity, pyrogenicity and sterility. Radiochemical purity is checked by the radio-thin layer chromatography (TLC) and by the radio-HPLC chromatography. During I8 the TLC method, a spot of 2-[ F] FDG is applied on a silica plate (POLYGRAM SIL G/UV254), which is developed in mobile phase (acetonitnle-water 95:5 Vol. %) and placed in a Nal(Tl) scanner. The HPLC method is carried out on the Nuclear Interface equipment containing a scintillation Nal(Tl) detector, an (JV-Visible detector and a refractive index detector Isocratic chromatographic separation of 2-['8F] FDG carried out on a DIONEX PA-1 column (4 x 250 mm) with 1M NaOH (lml/min) mobile phase. Traces of six radiochemical impurities in 2-[18F] FDG product were found. However content of these impurities is no higher than 5%. Chemical punty is checked by the HPLC method described above and by the gas chromatography (GC) method. The GC method occurred on the VARIAN Star 3400 CX gas chromatograph equipped with VARIAN VA-1 (60m x 0.25mm, l^m) capillary column and the (FID) detector. Nitrogen as carrier gas (35 psi) was used Sugar impurities D-glucose and 2-deoxy-2-chloro- D-glucose (CLDG) were detected by the HPLC method. The volatile substances methanol, ethanol, acetonitrile and acetic acid were detected by the GC method. Radionuchde purity is checked by decay curve analysing method with ATOMLAB 300 Dose Calibrator. During the time of finishing this abstract, it has made eight lots of 2-[18F] FDG product and preclinical tests has been performed. The current drift will be synthesized the 2-[18F] FDG for clinical tests. This work occurred under the support of the Internal Grant Agency of the Ministry of Health and the Ministry of Trade and Industry project

    -364- P7-18

    CHEMISTRY AND APPLICATION PROSPECTS OF TECHNETIUM(I) CARBONYL COMPOUNDS

    A. E. Miroslavov, G. V. Sidorenko, and D. N. Suglobov Khlopin Radium Institute, Research and Production Association, St. Petersburg, Russia

    A brief survey of technetium(I) carbonyl complexes, including preparation methods, chemical transformations, and prospects of application is presented. The most readily accessible Tc(I) carbonyl complexes are pentacarbonyl halides, which are prepared by halogenation of technetium decacarbonyl or by direct carbonylation of inorganic technetium compounds (e.g., KTcO4) with CO in the presence of corresponding hydrohalic acid (HO, HBr, or HI). Carbon monoxide can be generated by thermolysis of formic acid. In the case of HF, pentacarbonyl fluoride is not formed owing to hydrolysis and instability of the pentacarbonyl form in the case of strong and hard bases such as F" or OH"; the reaction product is C4F(OH)3(CO)i2. In the absence of a hydrohalic acid, the carbonyl hydroxide Tc,i(OH)4(CO)i2 is formed. Pentacarbonyl halides are thermally unstable and readily undergo decarbonylation with successive formation of Tc2X2(CO)8 and Tc4X4(CO)i2. The latter compounds have a cubane-like structure with u.3-halide ligands and terminal CO groups and are stable toward further decarbonylation. The instability of higher carbonyls is due to mutual trans effect of CO groups. The tendency to decarbonylation increases in the series I < Br < Cl < F, OH (in the latter case penta- and tetracarbonyl species were not obtained at all). The carbonyl groups in penta- and tetracarbonyl halides can be readily substituted by n-donor ligands such as ethers, amines, pyridine derivatives, etc. In the case of ligands that do not exhibit pronounced jr-acceptor properties, the final form, stable toward further substitution, is fac- tricarbonyl form. Halide anions can be substituted by other anions. In the case of strongly basic anions such as acetate, p-diketonates, etc., alkali metal salts can be used, whereas weakly basic anions should be taken in the form of salts with -accepting metals, e.g., silver. Substitution of the anionic ligand is often accompanied by decarbonylation to give the fac-tricarbonyl form The fac-tricarbonyl form is stable in complexing and proton-donor solvents, including water. The chemistry of technetium carbonyl complexes in aqueous solutions is now in an early stage of its development, but it is already clear that it is largely the coordination chemistry of the fac- Tc(CO)3 cation, which forms aqua and hydroxo complexes or complexes with other donor species present in solution. Many technetium carbonyl derivatives are readily volatile and can be used for chemical vapor deposition of technetium coatings, which are promising as sources of P-radiation (e.g., for protection of equipment from biological overgrowth in seawater). High corrosion resistance of such coatings makes them environmentally acceptable. A diversity of technetium(I) carbonyl derivatives that can be obtained by ligand substitution and stability of the tricarbonyltechnetium cation in aqueous solutions open possibilities for development of new radiopharmaceuticals based on short-lived technetium-99m. However, in this context it is necessary to study more actively the chemistry of technetium carbonyls in aqueous solutions and to develop quicker preparation procedures that would be suitable for trace amounts of the short-lived nuclide.

    -365- P7-19 SYNTHESIS AND THERMODYNAMIC RESEARCH OF THE PROCESS OF THE DEHYDRATION CRYSTAL MONOHYDRATE OF THE SELENITE OF THORIUM

    V.P. Nesterenko, V.P. Glybin Belaruslan State Technological University, Republic of Belarus

    This investigation relates to the field of radiochemistry technology of thorium. Contemporary technology makes a demand on compounds, possesing specific properties. One of such compounds is crystal monohydrate of the selenite of thorium Th(SeO3)2 H20. The information on its synthesis is given in this work for the first time. Amorphous basic selenites of thorium of non-constant composition are known. They are received by means of precipitation Th(IV) by selemous acid from neutral aqueous or ethanol solutions at molar quotient H2Se03:Th(IV) in the initial solutions, which is allied to stoichiometric [1]. But precipitation of Th(IV) is incomplete (output of thorium from water solutions up to 56%, and from ethanol solutions not exceeding 75%). The method of precipitation of thorium from solution provides reliable and displayable reception of monohydrate of selenite of thorium with the crystal structure with 100% output of thorium [2]. The synthesized monohydrate of selenite of thorium is the only oxygen-containing compound of thorium and selenium of strictly stoichiometric composition and consequently, can be used as a certain chemical agent in preparation chemistry and thorium technology. The synthesized compound was investigated with the assistance of X-Ray, denvatography, tensiometry and IR-spectroscopy. Its thermal decomposition has three stages:

    Th(SeO3)2 H2O (ct) Th(SeO3)2 ,„, + H2O <„ (428-515 K) (1) Th(SeO3)2(CT, ThO2SeO2«,r)+SeO2,s, (798 - 853 K) (2) ThO2SeO2(cr) ThO2(o,, + SeO2,g, (858 - 903 K) (3)

    Thermodynamics of dehydration Th(SeO3 )2 H2O(ct) was investigated with the help of static method with membranes zero-manometer. The process of dehydration is described in the following equation:

    The enthalpy and entropy of the process (1) in the investigated temperature interval are equal:

    AH°T= 92,9 + 2,1 kJ mol"'; AS°T =187,9 + 3,8 J mol''.

    These values, brought to standard conditions are equal:

    AH°298 = 94,1 + 2,9 kJ mol"'; AS%, =191,2 ± 4,5 J mol"'.

    1. The Actinide Elements. Edited by G.T. Seaborg and J.J. Katz. - New York (1954). 2 V.P. Nesterenko. Synthesis of the Selenite of Thorium. Certificate a. 582647 (1977).

    -366- P7-20

    THE POTENTIAL ROLE OF INTRACEREBRAL GLUTATHIONE IN THE RETENTION OF A REPRESENTATIVE 99mTc SNS/S MIXED LIGAND COMPLEX IN MICE BRAIN

    B. Nock, T. Maina, I. Pirmettis, M. Papadopoulos, C. Tsoukalas and E. Chiotellis Institute of Radioisotopes - Radiodiagnostic Products, NCSR ,,Demokritos", 153 lOAghia Paraskevi, Athens, Greece

    The two main "Tc radiopharmaceuticals applied today for brain imaging using Single Photon Emission Computed Tomography (SPECT) are ["™Tc]HM-PAO and ["""TclECD. These agents are small-size, neutral and lipophilic "Tc complexes that penetrate the intact blood brain barrier (BBB) by passive diffusion and are then retained in brain tissue for time sufficient to complete a routine diagnostic SPECT test. A different mechanism is underlying the retention of each one of these agents: While [""TcJHM-PAO suffers nucleophilic attack by intracerebral glutathione (GSH), ["""TcJECD undergoes ester hydrolysis of at least one of its pendant ester groups by brain esterases. As a result, the original "To compounds transform to more hydrophilic "To species in both cases thereby causing trapping of the radioactivity in brain cells [1,2]. In this work we report on the synthesis, radiochemistry and biodistribution in mice of 99m TcO{[(CH3CH2)2NCH2CH2N(CH2CH2S)2](p-SPh-COOCH2CH3)}, I. Complex I forms by reacting equimolar quantities of (CHjCH^NCHjCHjNtCH.CHjSH), and />-HSPhCOO-CH2CH3 ligands on "™Tcv-glucoheptonate ("Tc^GH). The latter is obtained by reconstituting a commercial GH kit with pertechnetate generator eluate (2-10 mCi, 1-2 mL). The labeled product is purified by organic extraction and HPLC. Its structure is established by chromatographic comparison with the analogous complex prepared at carrier level ("8Tc) and fully characterized by classical analytical methods. Formation of a single radioactive species of the expected formula is finally demonstrated. Stability of complex I versus GSH attack is first investigated in vitro, after incubation of I at 37° C with either 1 mM or O.I mM GSH solution in phosphate buffer pH 7.4. Monitoring the formation of a more hydrophilic 99mTc species follows the progress of the GSH nucleophilic attack by HPLC. It is found that the rate of this transformation is GSH concentration dependent. For tissue distribution studies HPLC purified I is injected in the tail vein of mice, that are sacrificed at 5, 30 and 60 min post injection. Distribution data shows that retention in brain tissue can be well correlated to in vitro findings from GSH incubation studies, given that GSH concentration in brain cells amounts to 2 mM Further studies are currently under way with the aim to establish the nature of the hydrophilic complex formed, as well as to demonstrate the importance and limitations of GSH role in the intracerebral trapping of 99n'Tc SNS/S mixed ligand complexes [3].

    References: Neirinckx RD, Burke JF, Harrison RC, Forster AM, Andersen AR, Lassen N A ./. ('ereb. HI. hi Metab.S: S4-S12; 1988 Walovitch RC, Hill TC, Garriry ST. Cheesman EH, Burgess BA, O'Leary DH, Watson AD, Ganey MV, Morgan RA, Williams SJ. J. Nncl. Med. 30: 1892-1901; 1989 Pirmettis 1C, Papadopoulos M, Chiotellis E../. Med. Chem. 40: 2539-2546; 1997

    -367- P7-21

    GAMMA-SOURCES BASED ON METALLIC AMERICIUM-241

    V.M.Radchenko, A.G.Seleznev, M.A.Ryabinin, and N.S.Kosulin SSC RF Research Institute of Atomic Reactors, 433510, Dimitrovgrad, Russia

    Gamma-sources are designed and manufactured from isotopic-pure metallic amencium-241 of activity from 0.08 to 0.93 GBq. The sources are stainless steel cylinders of 0 5 mm and 10 mm height. Core of source is americium-241 metallic condensate of high purity in the form of "spot" 0 4 mm on tantalum substrate which was fixed nearby one face of cylinder and isolated from outer surroundings by stainless steel of less than 0.1 mm thick Its core was prepared by 241Pu - 241 Am alloy thermal decomposition under high vacuum with evaporation of more volatile amencium on the substrate. The chemical and radiochemical purity of metallic americium is provided no less than 99.9%.

    -368- P7-22

    TECHNETIUM-99M PRODUCTION AT CENTRALISED GEL-GENERATOR ON THE BASIS OF MoO3

    I.A.Savushkin Institute of Power Engineering Problems National Academy of Sciences of Belarus

    Wasteless technology of 99mTc production at centralized generator in the form of sodium pertechnetate solution was developed in the Institute of Power Engineering Problems/ National Academy of Sciences of Belarus. All the investigations were carried out on the base of complex laboratory installation. The process suggested is based on the method of elution of ""'Tc from Zirconium-Molybdenum (Zr-Mo) gel. In 1989-1996 pre-clinical and clinical tests were carried out in the hospitals of Minsk and in the Scientific Research Institute of Oncology and Medical Radiology of Ministry of Health of Republic of Belarus. The application of centralized generator in ""Tc production will influence significantly the effectiveness and service costs of health protection owing to supplying of hospitals with cheaper and simplier source of Tc-production The irradiation conditions of target, consequence of technological process, technological yield of objective product on the example of operation of one generator, reprocessing and rendering of the wastes are analysed and described. The distinctive features of the technology developed are:

    • using of native molybdenum as start target, • absence of deleterious and toxic impurities in the final product (nitrates, organics, etc.); • the application of modified method of "Tc extraction from "Mo with the help of Zr-Mo-gel (that is the application of true gel but not the powder, obtained by gel drying) that allows to shorten the number of process stages and simplify the technology. It is very important at its remote realization; • the unit is readily automatized and remote-controlled; • simplicity of design and compactness offers wide application of the unit.

    -369- P7-23

    PHYSICAL AND CHEMICAL INVESTIGATIONS ON OPTIMIZATION OF Zr-Mo GEL-TECHNOLOGY OF 99mTc PRODUCTION

    I.A.Savushkin, V.P.Koudriashov, O.B.Gourko, E.I.Ravkova Institute of Power Engineering Problems / National Academy of Sciences of Belarus

    The results of complex of chemical and technological investigations performed on the base of laboratory installation with centralized Zr-Mo gel-generator where 12 g of MoOj was used as the initial target are presented in the paper. The investigations showed that when producing Zr-Mo gel it is necessary to pay specific attention to some parameters such as acidity, Zr:Mo ratio, time of gel maturation, volume of elution solution, etc. So, maximum level of ""Tc elution is reached when using of Zr:Mo mole ratio 1.2:1 and higher. It was experimentally determined that gels produced from Mo in monomeric state (with pH higher than 6.8) had sharply defined elution profile, but they were instable and gave Mo to eluate. With pH lower than 6.3 the formation of species in molybdate solution occured in the form of mixture of large polymeric particles. Therefore the pH range 6.3-6.8 is the optimum range for pH of gel in which pharmpreparation quality complies with requirements of Pharmacopoeia Standard.The obtained gel-matrix had both good stability and elutability of components dissolved in water This fact allows to produce Tc from "Mo in this matrix and then to eluate the subjective product, pharpreparation with ""Tc, from it. Elution profile was the other parameter effected the Tc yield quantity. Investigations of elution profile were carried out with Zr-Mo gel prepared from 12 g of irradiated MOO3. The investigations demonstrated that the dependence of percent "To yield had non-linear character The gel elution with 40-50 ml of saline solution was assumed as optimum. Under these conditions ""'Tc yield was 75-85%. For the comparison it could be said that 100 ml of saline solution eluated "To practically completely but specific activity of pertechnetate decreased by a factor of 1.5-2. Generator operation experience showed that while long operation the washing of H * ions from gel occured and that led to the increasing of pH and, correspondingly, to gel instability, increasing of "Tc yield and higher Mo breakthrough to the preparation simultaneously. Therefore conservation of optimum pH quantity was one of the technological tasks. This was achieved by the conditioning of gel with acidic solution, water and saline solution in every 3-4 days of generator operation. The investigations performed allowed to justify the technological reglament of sodium pertechnetate "Tc production on the basis of MOO3. When fulfilment of this reglament the characteristics of radiopharmpreparation of sodium pertechnetate solution "Tc supply the requirements of Pharmacopoeia Standard completely and specific activity in 5 ml of saline solution may reach 800-1000 MBq/ml during the first days of elution.

    -370- P7-24

    MEASUREMENT OF EXCITATION FUNCTION FOR 63Cu(n,p)63Ni REACTION UP TO En = 15 MeV

    S. Shibata,* T. Shibata, M. Imamura,** T. Ohkubo and S. Satoh Institute for Nuclear Study, University of Tokyo, Tanashi, Tokyo 188, Japan

    Y. Uwamino Institute of Physical and Chemical Research, Wako, Saitama 351-01, Japan

    N. Nogawa Radioisotope Centre, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan

    M. Baba, S. Matsuyama and S. Iwasaki Department of Quantum Science and Energy Engineering, Tohoku University Sendai 980-77, Japan

    The importance of neutron activation cross section is rapidly increasing from the view point of radiation safety as well as basic science. In the disassembling of the INS FM/FF cyclotron, which had been operated for about 25 years since 1958, we found 63Ni (Ti,? = 100 y) to be one of the most important residual radioactivities remained in the stainless steel and copper materials of accelerator equipments along with 55Fe (2.73 y) and 60Co (5.27 y) [1]. Among these nuclides, the 63Ni produced through the 63Cu(n,p) reaction supplies valuable information concerning the energy spectra of secondary fast neutrons. Also, to detect <3Ni is of interest in applications to estimate the neutron-energy spectrum from the atomic bomb at Hiroshima and Nagasaki [2]. We have, therefore, started to determine the excitation function for the 63Cu(n,p)63Ni, since the cross sections have never been measured, except for the neutron energy at 14 MeV. Irradiations were carried out at the Fast Neutron Laboratory of Tohoku University using the neutrons produced by the T(p,n), D(d,n) and T(d,n) reactions. The 63Ni was measured by the liquid-scintillation method after chemical separation of nickel from the copper target by anion exchange and solvent extraction. We report the cross section data at neutron energies around 1.5, 5 and 14 MeV.

    References [1] S. Shibata et al., INS Annual Report (1993) 101. [2] T. Shibata et al., J. Phys. Soc. Jpn., 63 (1994) 3546.

    •Present address: Research Reactor Institute, Kyoto University, Sennan, Osaka 590-04, Japan **Present address. National Museum of Japanese History, Sakura, Chiba 285, Japan

    -371- P7-25

    BIOSYNTHESIS OF 35S-LABELED NATURAL COMPOUNDS USING IN VITRO CULTURES OF HIGHER PLANTS

    S. SmrCek, L. LeSeticky, M. ZiCek, P. Koutnfk Department of Organic Chemistry, Faculty of Science, Albertov 2030, Prague, Czech Republic

    The plant cells are an excellent source of organic compounds. The ability of plant cells to synthesize a broad spectrum of organic chemicals could be used for the simple and elegant preparation of complex molecules. Especially, in the cases when conventional organic methods fails, or are extremely difficult. This aim could be well attained using in vitro cultivated plants or their tissue and organ culture. The accumulation of metabolites is often higher than in natural plants and the process could be better controlled. Variations of the cultivation conditions could enhance secondary metabolites production. The method can be used for the successful synthesis of labelled compounds, too. Inorganic form of radioactive element or physiologically available precursor of the resulting molecule could be used as a source of a radioactivity. Alternatively, the labelled compound with defined position of the radioactive atom may be synthesized. We prepared several 35-S labelled thiophene derivatives and l,2-dithiolane-3-pentanoic acid (a-Lipoic acid) by this way. The thiophene derivatives was previously described as a secondary metabolites of Tagetes sp.. 5-(4-hydroxy-1 -butynyl)-2,2'-bithiophene (1), 5-(4-acetoxy-l-butynyl)-2,2'-bithiophene(2), 5-(but-3-en-l-ynyt)-2,2'-bithiophene (3), and ct-terthienyl (4) . The seedling and root cultures of Tagetes patula cv. Valencia was cultivated on appropriate media with various 3SS sources (sulphate, thiosulphate, and elemental sulfur in dimethylsulfoxide). The plant material was than homogenized and above mentioned compounds was chromatographically separated. The structure was determined by mass spectrometry after gas- chromatography separation, and incorporated radioactivity by LSC. The compound 3 was i.e. isolated in the amount of 68 mg with specific activity 86.4 MBq/mol from 15.5 g fresh biomass On the other hand, a-lipoic acid is produced in a very small amount by the biomass and moreover, the produced compound is bound to proteins. The best results we achieved by using the suspension culture of Medicago sativa, when free labeled lipoic acid was successfully obtained.

    •on n (I /7 (I

    "^ (2)

    •OH (5)

    -372- P7-26

    [3H]ENDOMORPHIN II. A POTENT, SELECTIVE, TRITIATED ENDOGENOUS AGONIST FOR THE n-OPIATE RECEPTOR

    Cs. Tomboly, Zs. Lsiszl6, M. Spetea*, A. Borsodi*, G. Toth Isotope Laboratory and *Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, H-6'OI, Szeged, P.O. Box 521, Hungary

    Endomorphin I. (Tyr-Pro-Trp-Phe-NHb) and endomorphin II. (Tyr-Pro-Phe-Phe-NH2) have been isolated recently from mammalian brain1. The new peptides have the highest specificity and affinity for the ^-opiate receptor of any endogenous substance so far described and they may be natural ligands for this receptor. The precursor of the [3H]endomorphin II. was [3', 5'-diI-Tyr']-endomorphin II., which was synthesized by solid phase peptide synthesis on 4-methyl-benzhydrylamine resin using Boc-chemistry and was purified by HPLC on a reverse phase semipreparative column. [3', 5'-diI-Tyr']-Endomorphin II. was radiolabelled by catalytic dehalotritiation resulting in 1 3 [3 , 5'- H2-Tyr']-endomorphin II. The tritiated product has 1.98 TBq/mmol (53.4 Ci/mmol) specific activity. Labelled endomorphin II. was used to investigate its binding properties in rat brain membrane. The stability of [3H]endomorphin II. toward enzymatic degradation in membrane preparation was examined by incubating the radioligand with a membrane suspension in the presence and absent peptidase inhibitors, and was determined by HPLC using a radiometric detector. Association rate constant (k+1), dissociation rate constant (k.i), equilibrium dissociation constant (K4) and maximal number of binding sites (Bm) values were determined by kinetic and binding studies and found to be 0.088 ± 0.008 min'nM"1, 0.085 ± 0.001 min'1, 1.12 ± 0.25 nM, 114.80 ± 19.57 finol/mg protein, respectively. These data and the competition binding studies suggest that [3H]endomorphin II. is a very promising tool for identification and characterization of the n-opioid receptors in various tissues.

    1. J. E. Zadina, L. Hackler, L-J. Ge, J. Kastin; Nature, 386, 1997., 499-502.

    -373- P7-27

    TRACER TECHNIQUES IN STUDING GROUND WATER FLOW AND IT'S DISPERSION IN BEDROCK

    Pekka Viitanen VTTChemical Technology, P.O.Box 1404, 02044 VTT, Finland, tel. + 358 9 4566355, fax i 358 9 4566390, pekka.viitamnictyttji

    Tracer techniques has been used for in-siiu studies related to studies of the final disposal of nuclear waste in Finland. Major feature for the measurements is the possibility of very long breakthrough times. In order to get meaningful results in acceptable time proper planning and selection of the measurement target has to be done. Relatively simple means of verifying hydraulic connection is a pressure test where the effect of pressurising one borehole is monitored via other holes. An other quite convenient possibility is to pump water out of one hole and monitor the possible drop of hydraulic head in other holes In order to accelerate the flow rate of ground water a pressure gradient can be applied between the points of tracer input and output This has to be done with great care since changes in pressure conditions during the test may lead to futile results Tracer tests of several kind can be arranged. A simple test for measuring ground water flow rate through a packed off section of a bore hole is accomplished as dilution test. Tracer is mixed in a known volume and the concentration is decreased by the water flow from the rock to the packed off section and back to the rock. The flow rate can be calculated by the resulting exponential decay. Breakthrough tests offer a means to evaluate the nature of cracks and aquifers in rocks. A breakthrough test usually has to be done under the effect of artificial pressure gradient. The distribution of input concentration can seldom be considered as a delta-peak and, thus, deconvolution methods have to be used in extracting the residence time distribution from the measured tracer concentrations. The results of a breakthrough test can be used to verify flow models as well as to determine parameters for the flow models. A matrix diffusion model fits the present experimental data quite well The choice of tracer is essential in determining the nature of the tracer test. Main categories are tests with a conservative tracer or a tracer, which is delayed by chemical interaction with the rock matrix. Two main tracers, radioactive 82Br as KBr-solution and inactive sodium fluorescein (C2oHi0Na20s) have been used in the present tests. These two tracers are considered to be conservative. The use of slightly absorbing "To is being considered for the dilution tests. The test site for the present work has been a research tunnel situated 60 m below ground level, where bore holes of about 10 m deep have been drilled for test purposes. Successful dilution and breakthrough tests have been accomplished. Further tests aiming for a better knowledge of the flow geometry are presently being done and plans for accomplishing tests in deep boreholes (several hundred meters) are being planned

    -374- P7-28

    EFFECT OF GENTISIC ACID ON STABILITY OF TECHNETIUM - COLD KITS

    J.L.VuCina Vinca Institute of Nuclear Sciences Laboratory for Radioisotopes Belgrade, P.O.Box 522 Yugoslavia

    The effects of some impurities and additives which are regularly present in "mTc eluates or appear occasionally on the labeling of radiopharmaceuticals were examined The radiopharmaceuticals in the freeze-dried form and as a freshly prepared solutions were tested. The content of free pertechnetate in the samples was determined by several methods - paper and TL chromatography and electrophoresis. It was found that the increased content of copper affects the integrity of the preparation only in the case of methylene diphosphonate. Most kits are sensitive against the presence of hydrogen peroxide. Its content is higher in the case when air was introduced into the sample during preparation and dispensing. No effect of the increased content of long-lived technetium 99Tc was found. The effect of the experimental conditions on the stability of the kit was also determined. It was found that the kit could be stabilized by addition of antioxidants like ascorbic or gentisic acid. This procedure stabilizes the labeled preparations for six hours. In this paper the stabilizing effect of gentisic acid was tested on some technetium-cold kits. It was found that a kit solution can be kept at low temperatures under the condition that it contains the stabilizator. However its content should be much higher than in the case of stabilization of the labeled preparation.

    -375- P7-29

    PRODUCTION OF NEW RADIOISOTOPES ON THE ISOCHRONNOUS CYCLOTRON U-120M

    J. §tursa, J.Lacman, J. KuCera, M. tib&k, R. Jiran and M. Kfivinek Nuclear Physics Institute of Academy of Sciences, 250 68 kei, Czech Republic

    The 120 cm isochronnous cyclotron U-120M operated at the Department of Accelerators at N.P.I. Rez routinely produces commonly used isotopes "'Tl, 67Ga and mIn with the use of internal targetry. New isotopes i.e. 18F for PET studies or generator 81Rb/81lnKr for lung ventilation monitoring are produced on liquid or gaseous targets. These targets can not be placed inside the vacuum chamber because of their dimensions. Conversion of the cyclotron into H7D' machine and extraction high currents to the external positions by means of the stripping was necessary precondition for effective production of new radioisotopes. Development and modernization of the particular cyclotron subsystems (i.e. vacuum, central region, ion source, control system etc.) resulted in accelerating negative ions and employing the external targetry are presented. For technical and testing purposes we have decided to buy the 18F target system of GEMS production as a semi-product, i.e. without control unit, auxiliary circuits of compressed air and He and without control system. Development and realization of new control unit including software is described. Experience with irradiation and processing of liquid I8F and gaseous 8'Rb/81mKr targets will be published separately in our colleagues' contributions .

    -376- Topic 8

    RADIOCHEMICAL PROBLEMS IN NUCLEAR WASTE MANAGEMENT

    Verbal presentations

    -377- CZ9827876

    SOME RECENT DEVELOPMENTS IN SEPARATION METHODS FOR THE TREATMENT OF LIQUID RADIOACTIVE WASTES

    James D. Navratil Lockheed Martin Technologies Company, Idaho National Engineering and Environmental Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3921

    There have been many recent improvements in separation methods used for treating radioactive liquid wastes, from high level acidic wastes to wastewater. These improved methods have included adsorption, ion exchange, solvent extraction and other chemical and physical techniques. This paper will highlight some of these advances, especially areas experienced by the author, such as the use of magnetite for radioactive wastewater treatment. For example, magnetite (FeO.FejCb) has been used to separate a wide variety of substances, such as dissolved metal species, paniculate matter, and organic and biological materials (Boyd, et al., 1986). In the absence of an external magnetic field, activated magnetite readily adsorbs numerous metal species including actinide elements (Navratil, 1988). In an external magnetic field, a synergistic effect was observed in using supported magnetite in a fixed-bed for removal of plutonium and americium from wastewater (Kochen and Navratil, 1997). Using a magnetite-containing, nonporous polyamine-epichlorohydrin (MPE) resin bead, Kochen and Navratil observed that in the presence of a relatively weak magnetic field (0.3 Tesla), the capacity of the resin for both plutonium and americium increased by a factor of five compared to data that was obtained with unsupported magnetite particles in the absence of a magnetic field. These observations may be explained by a nanolevel HGMS effect, as plutonium and americium are known to form colloidal particles at elevated pHs (Ebner, et al., 1997). The pores of the MPE resin are large enough to permit the free displacement of the colloidal particles. When the field of the magnet is turned on, the magnetite particles are magnetically induced, creating a field that contributes to the net field sensed by the colloidal particles. In the absence of convection and when the magnetic force is sufficiently greater than the force associated with Brownian (thermal) motion, the magnetic force created by the field can be attractive and large enough to allow the magnetite to adsorb the colloidal particles. When the field is turned off, the nanoparticles are released and dispersed in solution by thermal motion (the metal ions would still be adsorbed, however). This process could be referred to as magnetic swing adsorption (Navratil, et al., 1995).

    Boyd, T. E., M. J Cusick and J. D Navratil, Recent Dev. in Separation Science, N.N. Li and J D. Navratil (Eds), Vol. VIII, CRC Press (1986). Ebner, A. D., J. A Ritter, and H. J. Ploehn, Separations Technology, (1997). Kochen, R.L. and J.D. Navratil, U.S. Patent 5,595,666, January 21, 1997, and U.S. Patent 5,652,190, July 29, 1997. Navratil, J. D., Australian Patent Application PJ0198, August 8, 1988. Navratil, J. D , R. L. Kochen and J. A. Ritter, Waste Management '95 Symposia, Tucson, AZ, February (1995).

    -378- CZ9827877

    DEVELOPMENT OF A UNIVERSAL SOLVENT FOR THE DECONTAMINATION OF ACIDIC LIQUID RADIOACTIVE WASTES

    T. A. Todd, K. N. Brewer, J. D. Law, D. J. Wood and R. S. Herbst Lockheed Martin Idaho Technologies Co., Idaho Falls, ID, USA

    V. N. Romanovskiy, V. M. Esimantovskiy, I. V. Smirnov and V. A. Babain V. G. Khlopin Radium Institute, Russia

    The cobalt dicarbollide solvent extraction process, originally developed in Czechoslovakia, and later in Russia, has been demonstrated to be effective at removing cesium and strontium from acidic waste solutions. A collaborative development program between the Lockheed Martin Idaho Technologies and the V. G. Khlopin Radium Institute has resulted in the development of alternative non-nitroaromatic solvents typically used in the cobalt dicarbollide process. Using the non-aromatic solvents, decontamination of acidic waste has been demonstrated using chlorinated cobalt dicarbollide with and without polyethylene glycol added. Polyethylene glycol facilitates the extraction of strontium in the cobalt dicarbollide process. A universal solvent has been developed which includes a phosphine oxide derivative added chlorinated cobalt dicarbollide/PEG solvent to facilitate simultaneous extraction of actinides, rare earth elements, technetium, strontium and cesium. This solvent was tested at the Idaho National Engineering and Environmental Laboratory (INEEL) in a series of batch laboratory contacts in a shielded hot cell facility using actual highly radioactive tank waste. Two solvents were tested, one less dense than the aqueous waste and the other more dense. Decontamination factors of >95% for Cs, 99.7% for Sr, and 99.99% for alpha-emitting radionuclides were achieved in four successive batch contacts. The universal solvent was also tested at the INEEL in a countercurrent process with simulated waste using 26 stages of 3.3-cm centrifugal contactors designed and fabricated by NIKIMT, Moscow, Russia. The process tested utilized the light solvent and europium was used to simulate rare earths and americium in the waste simulant. Results of the countercurrent flowsheet test will be presented. If successfully demonstrated, the universal solvent could offer many advantages to individual processes to remove radionuclides from the acidic waste at the INEEL. A significant reduction in the capital and operating costs of a waste treatment facility would be realized by implementation of a single process to decontaminate the waste

    -379- CZ9827878

    MEMBRANE TECHNOLOGIES FOR LIQUID RADIOACTIVE WASTE TREATMENT

    A. G. Chmielewski, M. Harasimowicz, Q. Zakrzewska-Trznadel Institute of Nuclear Chemistry and Technology Dorodna 16, 03-195 Warsaw (Poland)

    Membrane processes enable radioactive impurities to be separated from waste stream by selective passage of certain components of the stream through a membrane. These processes include reverse osmosis (RO), ultrafiltration (UF) or microfiltration (MF), depending on the pore size in the membrane. At Institute of Nuclear Chemistry and Technology (INCT) the membrane method for purification of radioactive wastes applied such processes as ultrafiltration, "seeded" ultrafiltration and reverse osmosis was developed. On the basis of the results obtained in laboratory experiments the pilot plant for radioactive effluents treatment was built. The plant was composed of UF unit (AMICON H 26P30 capillary module) and two RO units (N1TTO NTR 739 HF S-4 spiral wound LPRO modules). The capacity of the pilot plant was up to 200 L/h and the specific activity of wastes purified in the system - below 104 Bq/L Decontamination factor for entire system is higher than 5* 103. Another possibility for radioactive wastes treatment is membrane distillation (MD), non-isothermal process employing hydrophobic polymer membrane, which is developed at INCT now. Preliminary tests with liquid radwaste were carried out on laboratory unit with permeation test-cell holding flat sheet membrane. As a hydrophobic barrier membranes made of two polymers were used: polytetrafluoroethylene (PTFE) and polypropylene (PP) The process was arranged in direct contact membrane distillation configuration. The permeate condensed directly in the cold stream (distilled water) and retentate was enriched in radionuclides. The further experiments carried out with capillary module BFMF 06-30-33 (Euro-Sep Ltd.) with polypropylene capillaries, diameter 0.33 mm and cut off 0.6 \xm proved previous results. A pilot plant employing GORE-TEJC* membrane distillation was constructed The plant can clean the low-level radioactive wastes from nuclear centre, at a throughput -0.05 mVh.

    There are many advantages of membrane processes used for concentration of radwaste, including: 0 moderate operating conditions, 0 high decontamination factors, 0 low energy consumption, 0 volume reduction factors several times greater than that obtained by other methods, 0 the processes can be very easily combined with other methods for liquid waste purification, 0 the processes are versatile and with conjunction with absorbers or complexants may be tailored to treat wide range of waste streams. 0 simple apparatus, easy to join in series.

    -380- CZ9827879

    REMOVAL OF IODIDE ION FROM SIMULATED RADIOACTIVE LIQUID WASTE

    H. Kodama National Institute for Research in Inorganic Materials, Japan

    Various radioactive elements are produced in a nuclear reactor and their removal and solidification are a very important problem. The present paper discusses a method for removing radioactive iodide ions by fixing them onto an inorganic compound. In a previous study the synthesis, reactivity and stability of BiPbO2NO3 were reported. This material was designed for removal and solidification of halogenide ions. Moreover it was shown that the material is stable not only in pure water but also in strong acidic solution (pH=l) or alkaline solution (pH=13) and it works as a very useful ion exchanger to iodide", chloride2'and bromide31 ions in solution.

    This work describes the reactivity of BiPbO2NO3 with iodide ion in the simulated radioactive liquid waste. This solution is simulated low level radioactive liquid waste produced from a reprocessing plant and it contains 26 components, in which NaNC>2, Na2CO3 and NaNC>3 have the especially high concentrations (their total amount is about 400 g/1). First of all, the extent of the ion exchange reaction was examined at 25 °C and 50 °C as a function of time. The result shows that its temperature dependency is very small and that it comes to an end in short time. After several hours, the concentration of iodide ion remained in solution becomes almost constant. After 10 hours, for instance, the percentage of remained iodide ion was about 10 % but this value is very high as compared with the previous result (below 1 %)". Then the concentration change of unreacted iodide ions in solution was examined as a function of the amount of BiPbO2NO3 equilibrated with iodide ions. The result shows that the unreacted iodide ions decrease slightly with the increasing of BiPbO2NO3 but the change is very small. This indicates that the increment of total ion exchange capacity does not work effectively to decrease the iodide ions remained in the solution. Thermal and structural properties of the reaction products were studied to discuss the mechanism of the ion exchange reaction. A X-ray diffraction (XRD) pattern of BiPbO2NO3 after the reaction was found to be the same as before reaction. This does not mean BiPbCKNO 3 that does not play a part in ion exchange reaction but it can be explained by that the peaks of the XRD patterns of the reaction products are too week to be observed, because only the small area of BiPbC>2NO3 crystals reacts with iodide ions. Thermal properties were studied by TG-DTA/MS. The result shows that a part of the reaction products is decomposed at the temperatures between 315 °C and 455 °C and the decomposed compound contained CO3. This can be explained by that the crystal surfaces of BiPbC>2NO3 are covered with the compounds such as Bi2O2(CO3) This compound disturbs the further proceeding of ion exchange reaction with iodide ions. In order to get more information on the reaction of BiPbC^NOj with iodide ion under the coexistence with highly concentrated NO3" or CO32", the ion exchange reactions were examined by using two other simple solutions. The one contains Nal and NaNCh and the other contains Nal and Na2CO3. The effect of the coexisting anion to the ion exchange of BiPb02NO3 with iodide ion was examined as a function of the concentration of coexisting anion. 1) H.Kodama, The removal and solidification of iodide ion using a new inorganic anion exchanger, Proceeding of the Ion Ex'95 Conference, UK, 1995, p-39 2) H.Kodama, The removal of chloride ions using a new inorganic anion exchanger, Proceeding of the 1995 International Conference on Ion Exchange, Japan, 1995, p-285 3) H.Kodama and N.Kabay, Reaction of the inorganic ion exchanger, BiPbO2NO5 with bromide ion in solution, Proceeding of the 13'th Japan Ion Exchange Conference, Japan, 1997

    -381- CZ9827880

    NEW METHOD FOR SEPARATION OF RADIUM FROM RAMSAR AREA BY MGF • 48

    H. Ghafourian, M.R. Emami, A. Farazmand Research Center for Nuclear Standards, P.O.Box - 11365 - 8486, Tehran - Iran

    The investigation was made for separation of radium from aqueous media by using bactena MGF - 48. The maximum adsorption capacity was 60.000 pCi/g dry cell, and therefore among the microorganisms in the world, which have been reported till today, it is the kind with the highest ability to adsorb radium. The bacteria MGF - 48 can eliminate 89.06 percent of radium in the first cycle. The capacity of radium adsorption by biomass was found to be depended on pH of the feed solution, the best result was observed at pH = 7 using a contact time of seven minutes. The best conditions for removal of radium from bacteria cells are in the 0.1 molar solution of nitric acid (95.3 percent removed), similar results can be obtained by EDTA solution (93.65 percent removed). The capacity of radium adsorption by bacteria can be increased by adding 0.1 normal solution of sodium carbonate up to 51.8 percent. For the next experiments, fixed gel column was. The result have shown that the calcium alginate gel has good properties for adsorption and desorption of radium in fixed bed. From the economical and technical point of view, it is very convenient to use the gel in a large scale separation. ' The results of this research have shown that it is possible to design a bioreactor for separation of radium from contaminated water in Ramsar or other sources.

    -382- CZ9827881 ACTIVITIES OF THE IAEA IN THE AREA OF RADIOACTIVE WASTE MANAGEMENT

    V.M. Efremenkov International Atomic Energy Agency Vienna, Austria

    The IAEA activity in the area of radioactive waste management mainly concentrates on three areas, namely: - the establishing of international principles and standards for the safe management of radioactive waste; - to promote the development and improvements of waste processing technologies, including handling, treatment, conditioning, packaging, storage and disposal of waste; and - assisting developing Member States in establishing good waste management practice through dissemination of technical information, providing technical support and training. These activities are carried out by the Waste Technology Section, Department of Nuclear Energy, and the Waste Safety Section, Department of Nuclear Safety The Waste Technology Section's activities are organized into four subprogrammes covering: Handling, processing and storage of radioactive waste, Radioactive waste disposal; Technology and management aspects of decontamination, decommissioning and environmental restoration; and Waste management information and support services. In the subprogramme Handling, Processing and Storage of Radioactive Waste, special emphasis is being placed on safe, sound and cost effective methods to minimize the generation of radioactive waste, and on the promotion of effective technologies to manage all types of radioactive waste, e.g. the waste generated from nuclear power plants, fuel cycle facilities and nuclear applications. Quality assurance of waste packages required for safe transportation, storage and disposal is are also considered as an important project area within this subprogramme. The Radioactive Waste Disposal subprogramme is focused on planning, design, construction, closure and quality assurance of radioactive waste repositories for all types of radioactive wastes In the Decontamination, Decommissioning and Environmental Restoration subprogramme, attention is mainly given to nuclear power plants and fuel cycle facilities, although, in recognition of the specific needs of many Member States, some work is oriented on the decommissioning and associated problems at research reactors and non-fuel cycle facilities. The fourth subprogramme is concerned with the provision of information and supporting services to facilitate the establishment of technical infrastructure in accordance with the specific needs of Member States and to offer assistance in resolving special waste management problems. The detail information will be provided on the ongoing activities of the IAEA on the technological aspects of waste management, including information on the technical reports recently published or under preparation on different aspects of waste management.

    -383- CZ9827882

    NEW GENERATION OF COMPOSITE INORGANIC ION-EXCHANGERS WITH POLYACRYLONITRILE BINDING MATRIX

    F. Sebesta, J. John, A. Motl, K. Uvirova, S. SmrCkova Czech Technical University in Prague, Department of Nuclear Chemistry, Bfehovd T, 115 19 Prague 1, Czech Republic

    General procedure for treatment of powdered inorganic ion-exchangers using binding polymer - modified polyacrylonitrile (PAN) into beads suitable for the application in column packed beds was proposed earlier. These composite ion-exchangers were tested for many applications, some of them are used in the full-scale treatment of liquid radioactive wastes and/or for radioanalytical purposes New generation of the composite ion-exchangers was developed to improve their volume exchange capacity and mechanical strength. Further, composite absorbers with new active components or their mixtures were prepared. The possibility of preparation of magnetic composite adsorbers and magnetic composite ion-exchangers was also studied. The new prepared materials were mainly tested for their application in caesium separation From highly active acidic waste streams. The efficiency of AMP-PAN (ammonium molybdophosphate active component) and ferrocyanides based composite ion-exchangers for caesium separation was studied in more details. Possibilities of regeneration of the above mentioned composite ion-exchangers were also studied. In preliminary experiments, mercury sorption from model mixed radioactive wastes onto ferro- and ferncyanide based absorbers was tested. The new generation of composite ion-exchangers with hydrated titanium oxide or sodium titanate as active component was tested for strontium separation from alkaline solutions.

    -384- CZ9827883

    CAESIUM REMOVAL FROM FUEL POND WATER USING A COMPOSITE ION EXCHANGER CONTAINING NICKEL HEXACYANOFERRATE

    D.P. Field, K. Harding and E.W. Hooper AEA Technology, Harwell, Didcot, Oxfordshire 0X11 ORA, UK

    F. Sebesta Czech Technical University in Prague, Czech Republic

    1 Introduction The Al reactor at Bohunice was designed as a research/demonstration plant to assess the potential of a natural uranium fuel, gas-cooled, heavy water moderated reactor system. Spent fuel elements from the reactor were stored in a pond. To limit corrosion of the cladding, they were held within thimbles which contained a corrosion inhibiting solution of potassium chromate (Chrompik). This proved to be not effective enough, fuel pins did fail, releasing significant amounts of radioactive caesium and also, due to hydrogen gas pressurisation, significant amounts of contaminated Chrompik were released into the pond together with approximately 100 TBq of Csl37. This paper presents the work undertaken to remove this Csl37 as part of the first phase of decommissioning the pond.

    2 Design of A1 Pond Caesium Removal Plant The design is based on a skid mounted unit, comprising a shielded mechanical filter unit and a shielded ion exchange (IX) column unit, with interconnecting pipework and valves. The IX column is housed within a lead shielded overpack and connections to it are made by self-sealing quick release couplings. The IX column is of upward flow design and filled with a composite ion exchanger containing Nickel Hexacyanoferrate (II), developed at the Czech Technical University in Prague. The IX column packages may be stored within their own shielding once spent

    3 Results from Operational Programme Two operational runs have now been completed, removing 25 TBq of Csl37 in each run. With a fresh column, the Decontamination Factor (DF) for Csl37 uptake was initially over 5000. The DF then fell slowly over the first 1000 bed volumes to 3500, where it remained for most of the run. The run was terminated when calculations indicated that the column packing had absorbed the specified maximum loading of 25 TBq of Csl37. At this point the DF was 1500 The rate at which the Csl37 concentration fell in the pond during both operations followed very closely the theoretical removal curve for total mixing of the return water with the pond, showing that the locations for the outlet and inlet points for the plant had been well chosen.

    -385- CZ9827884

    AMP-PAN COLUMN TESTS FOR THE REMOVAL OF i37Cs FROM ACTUAL AND SIMULATED INEEL HIGH-ACTIVITY WASTES

    K. N. Brewer, T. A. Todd, D. J. Wood, P. A. Tullock Lockheed Martin Idaho Technologies Co., Idaho Falls, ID, USA F. Sebesta, J. John, A. Motl Czech Technical University in Prague, Czech Republic

    The cesium composite inorganic-organic ion exchange material AMP-PAN (ammonium molybdophospahate in polyacrylonitnle binding matrix), was recently tested at the Idaho National Engineering and Environmental Laboratory (INEEL). Small-scale tests using a column having a bed volume of 1.5 mL were performed in a shielded hot cell with actual INEEL high-activity waste. Tests were also performed with an identical column using simulated INEEL waste spiked with B7Cs. Over 1500 mLs of actual waste from tank WM-183 were processed through the 1.5 mL column using upward flow at a rate of 40 mL/hour. The column effluent was sampled every hour and the percent B7Cs breakthrough (C/C x 100) was plotted as a function of bed volumes (BV). Results showed that only 0.13 % 137Cs breakthrough was achieved after 1030 BV (1546 mL). Cesium was eluted from the column with 5 M NH4NO3 in 0.1 M HNO3 at a flowrate of ~ 8 mL/hour and using reverse or downward flow. Over 83 % of the 137Cs was eluted in 44.4 mL (29 BV). The column effluent sample fractions were re-combined after column elution and mixed with some original unused waste from Tank WM-183, then ran through the column again after the column was washed with 10-15 mL of 0.1 M KNO3 in 0.1 M HN03. A flowrate of 40 mL/hour was again used, and column effluent samples were taken every 3 hours. The breakthrough of B7Cs as a function on BV was plotted again, using B7Cs activity in the re- combined feed as Co. Cesium breakthrough of 0.5 % was observed after 1270 mL of waste was re-processed. Two loading and elution cycles were performed with simulated INEEL waste spiked with B7Cs. A B7Cs breakthrough of 1 % was observed at 922 BV for the first loading cycle, which is approximately one order of magnitude larger than that observed with actual waste. Approximately 4800 mL (3200 BV) of simulant was processed before 50 % breakthrough was observed. Over 70 % of the loaded Cs was eluted in 85 mL (57 BV). Only 4050 mL (2700 BV) of simulant was processed before 50 % breakthrough during the 2nd loading cycle and 50 % of this cesium was eluted in U7mL(78BV). These results show AMP-PAN to be very effective in removing 137Cs from ICPP acidic waste. A cesium decontamination factor of >3000 was achieved in the actual waste test. Tests with actual waste and simulant indicate the AMP-PAN composite to be regenerable and have a large capacity for cesium.

    -386- CZ9827885 ON THE USE OF HEXACYANOCOBALTATES IN THE SEPARATION OF CAESIUM FROM RADIOACTIVE WASTE SOLUTIONS

    F.M. Mekhail Atomic Energy Authority, Hot Laboratory Centre, P.Code 13759, Egypt

    This paper reviews our work on the use of hexacyanocobaltate salts in the chemical treatment of radioactive waste solutions. The divalent cations of the 3d - block elements together with the hexacyanocobaltate moiety form insoluble polymeric coordination compounds. These compounds have been used as chemical precipitants or ion exchangers for the separation of radiocaesium from various simulated and actual waste solutions. Precipitation in situ has been performed by using various hexacyanocobaltate salts of the divalent cations of Mn, Fe, Co and Ni. The results showed that Co2+ and Ni2* salts have high selectivity for caesium. The presence of monovalent cations and detergent has significant effect on the precipitation process. On the other hand Cd2* salt has been found to be more stable than other salts in alkaline medium. The sorption properties of hexacyanocobaltate salts as ion exchangers were studied. Adsorption of caesium seems to proceed via an ion exchange mechanism. It has been used for the treatment of reprocessing medium active waste solution. A decontamination factor of about 103 has been achieved.

    -387- CZ9827886

    IMMOBILISATION OF STRONTIUM, NICKEL AND IODIDE BY A SULPHATE-RESISTING PORTLAND CEMENT

    E. Wieland, J. Tits, P. Spieler, J-P. Dobler Waste Management Laboratory, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

    Cement-based materials are planned to be employed as main barriers in L/ILW repositories. Hence an understanding of the immobilisation of radioactive waste in cement is required for performance assessments. In this study, the interaction of Sr(II), Ni(II) and I(-I) with sulphate-resisting Portland cement was investigated under highly alkaline conditions. High pH conditions were predicted to occur in a L/ILW repository due to the evolution of the pore water composition during leaching of cement by groundwater. The study is a part of an experimental programme focusing on processes governing the radionuclide uptake at trace levels and obtaining a consistent data set for modelling the uptake by cement under chemical conditions relevant to a cementitious near-field. Batch-sorption studies were performed by contacting HTS cement (Ziaute /eneur en silice, sulphate-resisting Portland cement, Lafarge, France) with artificial cement pore water (ACW). The composition of ACW was 0.18 M KOH, 0.114 M NaOH and 1.2 mM Ca(OH)2 according to the composition of a (K,Na)OH dominated cement pore water in the initial stage of cement degradation 85Sr, 63Ni and I2!I were used as tracers. In the experiments with Sr(II) and Ni(II), isosacchannic acid (ISA) was added to ACW in concentrations ranging from 10'! M to 10'2 M in order to study the effect of complexing ligands on radionuclide retention. ISA is the dominating product in the degradation of cellulose in a cementitious repository. In a first stage of the study, the stability of the tracer solutions and the cement suspensions were assessed. Moreover, the inventory of the stable elements were determined in cement and cement pore water. We then studied the kinetics of the radionuclide-cement interaction process and measured the dependence of the distribution ratio (Rj) on the concentration of ISA and on the concentration of cement particles (S:L ratio). One of the goals of the current programme is to identify the chemical processes governing the retention of radionuclides by HTS cement. Evidence for the uptake mechanism for Sr(II), Ni(II) and I(-I) was anticipated from investigations of the dependence of the distribution ratio (R

    -388- CZ9827887

    PEROVSKITE AS A MATRIX FOR INCORPORATION OF LONG-LIVED RADIONUCLIDES

    N.E. Cherniavskaya,* A.V. Ochkin*, S.V. Chizhevskaya*, S.V. Stefanovsky*' *D.Men(Jeleev University of Chemical Technology of Russia, Miusskaya 9, Moscow, Russia, **SIA "Radon", 71* Roslovskiiper. 2/14, Moscow 119121 Russia.

    Synroc is titanate ceramics consisting mainly of zirconolite, perovskite, and hollandite, developed in Australia to immobilize high level waste for a long-term storage [1] Among high level waste radionuclides, long-lived isotopes are the most dangerous. One of the Synroc constituents is perovskite able to incorporate strontium, yttrium, and tnvalent lanthanides and actinides [1]. The main goal of the present work is leaching study of various radionuclides from perovskite. These data will be useful at modeling of radionuclides behavior in ceramics of various composition. Samples of perovskite-rich ceramics were produced by cold pressing of oxide mixture followed by firing in resistive furnace at 1350 °C for 3 hours. The samples prepared were examined with X-ray diffraction (XRD) using Cu Ko-radiation To perform leaching tests, ceramic pellets were crushed and surface areas were measured using argon thermal desorption technique. Leach rate was measured by means of boiling in Soxhlet apparatus for 5 hours every day. Leach rates in 0.1 M HNO3 and NaCl solutions were measured by boiling with stirrer and reverse cooler. Leach rate was controlled with radioactive indicator technique. Density of the perovskite-rich ceramic samples prepared was about 75% of theoretical. From XRD examination, the target phase (perovskite) yield was found to be about 95 vol.%. Minor rutile (< 5 vol.%) was also present.

    Leach rate of'"Sr from Sr-doped perovskttes with specified composition Cai.xSrxTiOj did not depend on x until certain x value. Leach rate of WST from control zirconolite sample was by one order of magnitude higher than from perovskite. Leach rates of l47Pm, 238Pu, and 241Am from perovskite ceramics with nominal perovskite composition had the same order of magnitude (~10'4 g/(m2day)) Substitution of 5 at.% Ce for Ca and 5 at.% Al for Ti lowered leach rate of 23SPu by a factor of 6 compared to perovskite with normal composition. Leach rates of '"Sr in 0.1 M HNO3 and NaCl solutions were found to be by three and one orders of magnitude higher than its leach rate in distilled water. Future work will be directed to determination of more precise x value which results in increase of ^Sr leach rate in series Cai-xSrxTiO3, and study of leaching of other radionuclides simulating long-lived high level waste constituents from synthetic perovskite-rich ceramics as well as investigation of effect of mechanical activation parameters on kinetics and mechanism of solid state reactions in CaO-TiOrwaste oxides system and product properties

    REFERENCE

    1. A.E. Ringwood, S.E. Kesson, K.D. Reeve, DM. Levins, and E.J. Ramm, "SYNROC", in Radioactive Waste Forms for the Future, eds. W Lutze and R.C. Ewing, Elsevier Science Publishers B.V., 1988. P. 233-334.

    NEXT PACm -389- left BLAUK Topic 8

    RADIOCHEMICAL PROBLEMS IN NUCLEAR WASTE MANAGEMENT

    Poster presentations

    -391- P8-1

    GRANITE AND APATITE BASED CERAMICS AS MATRIX MATERIALS TO IMMOBILISE THE RADIOACTIVE WASTES

    N.L.Arancibia, R.V.Bogdanov, V.B.Glushkova1', R.A.Kuznetsov, V.A.Krshishanovskayai),T.I.Panova1), A.S.Sergeev St.Petersburg State University, St.Petersburg, Russia " Institute of Silicate Chemistry, Russian Academy of Sciences, Russia

    The ceramic materials on the basis of a granite and apatite are studied as matrixes for the immobilisation of Sr-90 and Cs-137 from the radioactive wastes. Components of the ceramics: granite (G/VR), apatite ore (AO) and simulated radioactive waste (SRW), were crushed up to medium size of particles (10 microns). The mixtures of two compositions were prepared: 1) G/VR - 70 %, SRW - 30 %; 2) G/VR - 30 %, SRW -30 %, AO - 40 %. The samples were pelletted under the pressure of 960 kg/cm2 and annealed at two temperatures - 850°C and 900°C - during 1 hour and 4 hours (8 various combination altogether). That corresponded to realisation of the complete two-level three-factor experiment of a kind 23. As optimised parameters of the experiment, the differential rates of leaching R (g/cm2 day) for Sr and Cs were used. The leaching was carried out at temperature (86 ± 1)°C by doubly distilled water in teflon cells. The change of water was carried out daily. The ratio of a pellet surface to volume of a liquid phase was 0,5-0,9 cm"1. The determination of Sr and Cs has been carried out by the method of flame emission spectrophotometry. The experimental data of R(t) for Cs were approximated by equation of the form R=A + Bt, for Sr a hyperbolic function R=A + Bt"1 was used. 16 values of R for t=28 days were used to complete the matrices of planning as a response functions. Two regression equations of the following kind were obtained: 3 3 a a x a x y = o + S i i + £ ij iXJ + a123x1x2x3 i=l i 10'5 g/cm2 day). As a result of the study, it has been recommended to keep the contents of the radioactive waste of this type in ceramics at the level not exceeding 15%

    -392- P8-2

    ADSORPTION OF Sr ON ILLITE

    Binay Bilgin, Giilten Atun, Goniil Kejeli Department of Physical Chemistry, Faculty of Engineering, Istanbul University, Avcilar 34850 Istanbul, TURKIYE

    Adsorption of strontium on illite has been studied as a function of time, particle size, ratio of solution volume to weight of clay and concentration of adsorbate. The adsorption experiments were carried out using the batch method. Initial concentrations of Sr* ions ranged from lO"* to 101 M and used Sr-90 as a tracer. The influence of Ca++ and Ba** cations on Sr adsorption were also studied. These effects are correlated with the ionic radii of alkaline earth ions present in the solution. The Freundlich and Dubinin Radushkevich (D-R) isotherm have been applied to the data and the values of parameters of these isotherm equations were calculated. The mean energy of adsorption, E was also calculated from the adsorption energy constant, K and maximum capacity Xm values determined from linearised D-R equation. From empirical Freundlich parameters a site distribution function was calculated.

    -393- P8-3

    REMOVAL OF URANYL IONS FROM RESIDUAL WATERS USING SOME ALGAE TYPES

    Al. Cecal1', V. Rudic2', A. Gulea3', Iliana Palamaru1', Doina Humelnicu1', V.V. Salaru2' and K. Popa1' 1) Faculty of Chemistry, Al.I.Cuza University, last, Romania 2) Institute of Microbiology, Academy of Science, Kishinew, Republic of Moldova 3) Faculty of Chemistry, Slate University, Kishinew, Republic of Moldova

    This paper deals with a study of the bioaccumulation of uranyl ions from residual effluents by means of some microbiological collectors: Scenedesmus quadncauda, Anabaena karakumica, Calothrix brevissima, Penicillium sp., as well as the Glucide extract of Porphyridium cruentum, in several experimental conditions. The retaining degree of the bioaccumulated uranyl ions, as well as the leaching degree in HCl and H2O media, of the same ions previously retained on algae, were established. The retaining degree decreases in the serie Scenedesmus quadricauda > Anabaena karakumica > Pemcillium sp. > Calothrix brevissima. The leaching effect of bioaccumulated uranyl ions is higher in hydrochloric acid than in water.

    -394- P8-4

    BOROSILICATE HIGH SILICIOUS ZEOTYPE MATERIALS USED FOR IMMOBILISATION OF CAESIUM FROM RADIOACTIVE AQUEOUS WASTE SOLUTION

    Shabid Khan Durrani, N. A. Chughtai and Javed Akhtar Nuclear Materials Division, Pakistan Institute of Nuclear Science and Technology, P. O. More, Islamabad, PAKISTAN

    High silica crystalline microporous materials are expected to be used as an admixture to cement, glass-composite materials to increase their ion exchange ability. Boron containing high silicious zeotype materials such as B-ZSM5, B-ZSM11 and B-BETA are surprisingly effective for removing the corrosive fission element like caesium from radioactive waste liquors. Due to the replacement of aluminium in the zeolitic framework the radwaste-loaded materials can also be consolidated with glass at lower temperature. The present research work provides a process for removing the radioactive caesium from aqueous waste solution using high silicious zeotype materials, admixing the said radioactive ion containing zeotype material with a soft glass powder to form a mixture and sintering the mixture to form glass-like melt. The medium and large pore zeotype materials as desired for the process have been synthesised hydrothermally from the aqueous silicate gels of NaaO-SiOz-AkOj^CVKC^^NkO-I^O. The crystalline products have been characterised by cation exchange capacity (CEC), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTir), thermogravimetric analysis (TG-DTA) and surface area determination.

    -395- P8-5

    REMOVAL OF SOME RADIOACTIVE NUCLIDES BY IN-SITU PRECIPITATION WITH ION EXCHANGE MATERIALS

    I.M.El-Naggar, E.S.Zakaria, M.M.Abou-Mesalam and H.F.Aly Atomic Energy Authority, Hot Labs. Centre, P.Code 13759, Cairo, Egypt

    Precipitates of some radwaste elements (134Cs, 60Co, 85Sr and l!2"4Eu) with cenum(IV)- and tin(IV) antimonates in presence of 10"*M of each Cs , Co2', Sr2 and/or Eu3* have been prepared by in-situ precipitation. It was found that all the precipitates produced prefer ions of smaller ionic radii. The distribution coefficient of Cs', Co2*, Sr2' and Eu3' onto all the products were determined and it was found that the separation factors between neighbouring pairs of metal ions are larger on tin(IV) antimonate (SnSb) than cenum(IV) antimonate (CeSb). The adsorption of Cs', Co2', Sr2' on CeSb and SnSb column beds were investigated and the preliminary results given here demonstrate the promise of potential applicability of these materials in many separations connected with nuclear fuel cycle activities.

    -396- P8-6

    ANODIC OXIDATION OF THE CARBON-14 LABELED ORGANIC WASTE

    E. F6rster, K.H. Heise, H. Nitsche Forschungszentrum Rossendorfe. V., Institute of Radiochemistry, P.O. Box 510119, D-01314 Dresden, Germany

    Bariumcarbonate C-14 is a widely accepted stable chemical form for safe disposal of carbon-14. This requires, however, oxidation of carbon-14 containing organic waste to carbon dioxide. We have developed a method for mineralisation of organics by anodic oxidation in a silver sulfate containing sulfuric-chromic acid. This process also can be used for complete oxidation of ..difficult,, organic wastes, esp. hydrophobic substances like hydrocarbons, plastics, activated carbon, etc. Chromium containing hazardous wastes are avoided by electrolytic regeneration of chromium(III) to chromium(VI) in this process The degradation of C-14 labeled organics during the experiments is monitored by on-line measuring of irradiation of 14CO2 produced.

    -397- P8-7

    PHYSICO-CHEMICAL STUDIES INVOLVING INCORPORATION OF RADIOACTIVE AND INDUSTRIAL WASTES

    N. Hafez and M.S. Sayed Atomic Energy Authority, Hot Laboratories Centre, Cairo, EGYPT.

    Cement and some improving chemical additives is proposed to incorporate different types of wastes. The study is extended to prepare different mixtures of cement and these improving chemical additives in presence of some toxic ions. The physical, mechanical and leaching properties of the mixtures were studied. The thermal analysis and infrared spectra were also investigated.

    -398- P8-8

    QUANTITATIVE DETERMINATION OF THORIUM, URANIUM AND SOME FISSION PRODUCTS FOUND IN INDUSTRIAL AND RADIOACTIVE WASTE

    N. Hafez and M.S. Sayed Atomic Energy Authority, Hot Laboratories Centre. CAIRO. EGYPT.

    The reaction of thorium, uranium and some fission product elements namely cerium, praseodymium and with haematoxylin in presence of cationic surfactant cetyltrimethyl ammonium bromide (CTAB) were spectrophotometrically investigated. The formed complexes had an absorbance maximum lying between 400 nm and 650 nm. The molar absorptivities for each complex were calculated. Beer's law is obeyed up to 100 ugl'' of Th IV and U VI, and up to 10 ngml' for Ce III, Pr III and Sm III. The effects of reagents and CTAB concentrations, pH, time and interfering ions are discussed. This method was applied to the determination of trace amounts of Th IV, U VI, Ce HI, Pr HI and Sm HI in radioactive and industrial wastes

    -399- P8-9

    DISSOLUTION, SORPTION, AND COLLOID GENERATION IN CEMENTITIOUS MATERIAL-WATER SYSTEM

    Takeshi Iwaida, Shinya Nagasaki, and Satoru Tanaka Department of Quantum Engineering and Systems Science The University of Tokyo

    Cementitious material will be used as solidification, backfill, and construction materials for radioactive waste geological disposal. Atkinson et al.[l] have proposed long-term cement dissolution model. In this model, at first the pH of solution with which OPC (ordinary portland cement) is equilibrated will become 12.5—13 because Ca(OH)2 dissolution dominates pH After Ca(OH)2 in OPC completely dissolved, C-S-H gel begins to dominate pH. The pH decreases from 12 5 to the pH of solution of groundwater with the progress of C-S-H gel dissolution and the decrease in its Ca/Si ratio When the form of OPC is powder, this model is correct. However the dissolution behavior of cement biock may not be predicted by Atkinson's model because the model does not consider the dissolution kinetics. In the present work, we investigated the dissolution of cement block and found that Ca, Si, Al, and S were gradually released from the surface This phenomenon indicates that the dissolution of cement block does not occur uniformly and we have to consider the dissolution not only by an equilibrium model but by a kinetics model. Furthermore precipitation on cement surface was observed by SEM. Such surface alteration influences the sorption of cations and anions on cementitious materials. By applying a surface complexation model to Ca-Si-HiO system, the surface electric potential is evaluated. The surface electric potential was found to decrease from positive to negative with 2+ 2 decrease in solid Ca/Si ratio of solid phase. Experimental results of sorption of Sr and CrO4 " on C-S-H gels of various Ca/Si ratios were successfully predicted by the surface complexation model and surface potential evaluated. The importance of colloid generation and its influence on migration of radionuclides has been pointed out. It has been thought that silica colloids do not generate in the solution at pH>10.5. However, considering the pH variation, high ion strength, and existence of Fe and Al ions, there is a possibility that some colloids generate in cement dissolution system. We investigated the colloid generation, and its influence on radionuclides migration by taking into account dissolution and sorption of cementitious material.

    [1] Atkinson, A., et al, AERER12961, UKAEA (1988)

    -400- P8-10

    LABORATORY RADIOCHEMICAL SET-UP OF CENTRIFUGAL EXTRACTORS

    G.Kuznetsov, A.Pusbkov and L.Shklyar NIKIMT, 43, Allufievskoe sh., 127410, Moscow, Russia; Tel/Fax: (095) 487 03 24

    The paper describes the laboratory set-up of centrifugal extractors for the testing of technological flow-sheets of radioactive solutions treatment in «hot» chambers. The utilization of the centrifugal extractors allows to test a multistage process using minimum volumes of solutions with minimum time of achievement of steady-stage behaviour. The extractors can operate with any flow rate ratio of solutions in a wide range of their density ratio. They are reliable in an operation and simple in a maintenance with manipulators. The extractors made from stainless steel and titanium. The number of stages in the set-up is determined by technological requirements. These installations have been used for the testing of flow-sheets of irradiated nuclear fuel reprocessing, including a spent fast fuel, as well as for processing liquid radioactive waste. The results of these testings are also included in the paper.

    -401- P8-11

    SORPTION BEHAVIOUR OF URANIUM ON ACTIVATED BENTONITES FROM AQUEOUS SOLUTIONS

    Mehmet Mahramanlioglu, Ayben Kilislioglu, Melda Tun^ay Department of Chemistry, faculty of Engineering, Istanbul University , 34850 Avcilar -Istanbul -Turkey

    There are several techniques for removing uranium from contaminated water. The important uranium removal methods are conventional coagulation, filtration with iron and alum, lime softening, ion exchange by cation or anion resin, electrodialysis and adsorption: each has its merits and limitations in application. The aim of this study is to examine the adsorption characteristics of uranium onto acid and heat treated bentonite in order to compare efficiency in removing process. The experimental data have been fitted to Langmuir equation to calculate the adsorption capacities. Freundlich and DR isotherm parameters were also found. Bangham equation has been applied to the adsorption process and it was shown that the diffusion of uranium ions into the pores of the activated bentonite controlled the adsorption process. Temperature effects have been studied and the mean energy of adsorption was calculated for each adsorbents.

    Among the natural, acid treated (1-3M H2SO4) and heat trated bentonites, the most efficient one in removing uranium was found to be bentonite samples treated with 3M H2SO4.

    -402- P8-12

    THE ADSORPTION OF URANIUM FROM AQUEOUS SOLUTIONS ON ACTIVATED USED TIRES

    Mehmet Mahramanlioglu, Irfan Kizilcikli, I.Ozlem Bi9er, Melda Tun^ay Department of Chemistry, Faculty of Enginering, Istanbul University, 34850 Avdlar- Istanbul Turkey.

    A large mountain of tires generated each year in the world represents a fire hazard and takes up large amount of landfill space. A good solution from an environmental and economic standpoint is thermally reprocess the tires into valuable products. The aim of this study is to produce char from used tires and compare the sorption behaviour of uranium on these char samples activated with various concentrations of H2SO4 (1-3 M). Equilibrium modelling has been carried out using Langmuir and Freundlich equations and the adsorption capacities of the adsorbents have been determined. Thermodynamic parameters such as free energy, entalphy change and entropy change for sorption process have been calculated. The results showed that the major factors controlling rate of adsorption from aqueous solutions were film and intraparticle transport and activated used tires had a significant capacity for adsorption of uranium from aqueous solutions.

    -403- P8-13

    ION EXCHANGER IN RADIOACTIVE WASTE MANAGEMENT. PART XII: REMOVAL OF BARIUM AND STRONTIUM IONS FROM AQUEOUS SOLUTIONS BY HYDROUS FERRIC OXIDE

    Shuddhodan P. Mishra* and Dhanesh Tiwary Nuclear and Radiochemistry Laboratory, Department of Chemistry, Banaras Hindu University, Varanasi-221 005, INDIA

    Since the advent of nuclear industries, various approaches and technologies have been developed and adopted for the disposal and immobilisation of radioactive aqueous wastes generated at different stages of nuclear fuel cycle. The treatment process based on adsorption/ion exchange phenomenon plays an important role in pre-concentration/separation of toxic radionuclides from aqueous wastes. A variety of sorbents/ion exchangers find their application in the treatment of diverse type of radioactive aqueous waste. The sorption behaviour of oxides and hydrous oxides of polyvalent metal ions make them promising candidates for potential application in radioactive aqueous waste treatment as they are expected to play an important role in regulating the migration of radionuclides because of their widespread natural existence, high sorption capacities and selectivities for certain ions, high thermal, radiation and chemical stability and compatibility with various immobilisation matrices. In the present work hydrous ferric oxide was synthesised in accordance with the method reported in the literature and laboratory study was conducted to address its application for decontamination of barium and strontium ions from simulated radioactive wastes. The adsorption of Ba(II) and Sr(II) on hydrous ferric oxide was studied as a function of contact time, concentration, temperature and pH of the respective adsorptive solutions using 'radiotracer technique' The uptake of both the ions was found to increase with the increase in concentration, temperature and pH of the aqueous solutions. Concentration dependence data fitted well for Freundlich adsorption isotherm over the entire range of concentration (10'2-10'7M) and uptake process follows the first order kinetics. The desorption experiment demonstrates the irreversible nature of the uptake process; however, in the presence of H+ ions, i.e. on acidification, appreciable amount of metal ions were regenerated. Also, the presence of some co-ions (mono- and divalent metal ions) suppressed the process appreciably. The radiation stability of hydrous ferric oxide towards the uptake of Sr(II) was also examined by using pre-irradiated hydrous ferric oxide as adsorbent.

    -404- P8-14

    ZIRCONOLITE AS A HOST PHASE FOR URANIUM INCORPORATION

    A.V. Ochkin*, S.V. Chizhevskaya*, S.V. Stefanovsky**, S.N. Dmitriev***, L.G. Molokanova*** *D. Mendeleev University of Chemical Technology of Russia, Miusskaya 9, Moscow, Russia; **SIA "Radon", 7thRostovskiiper, 2/14, Moscow 119121 Russia; ***Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna 141980 Moscow reg. Russia.

    The major problem of nuclear technology is safe disposal of radioactive wastes. Actmides are the most dangerous nuclear waste constituents at long-term storage of waste. Zirconolite-rich ceramic was proposed to incorporate long-lived radionuclides [1]. Zirconolite is able to accommodate tetravalent actinides (U4+, Pu4*), and some fraction of trivalent actinides and rare earths (Am3*, Cm3*, Nd3*, Gd3*, etc.) [1,2]. The goal of the present work was to measure uranium leaching from synthetic zirconolite-rich ceramics. The results obtained will be useful for modelling uranium behaviour in various ceramics.

    Samples of the zirconolite-rich ceramics with composition CaZri.BUxTi207 (0

    REFERENCES

    I. E.R Vance, C.J Ball, R.A. Day, K.L. Smith, M.G. Blackford, B.D Begg, P.J. Angel, J Alloy and Comp. 213/214 (1994) 406 2 E.R. Vance, A Jostsons, R.A. Day, C.J. Ball, B.D. Begg, P J. Angel, Mat. Res. Soc Symp. Proc. 412(1995)41. 3 V.M. Oversby, A.E. Ringwood, Rad. Waste. Manag. 2 (1982) 223.

    -405- P8-15

    CONCENTRATING CAESIUM, STRONTIUM, REE AND ACTINIDES INTO ZIRCONIUM-PHOSPHATE CERAMIC MATRIX ATTACHED TO NUCLEAR WASTE FORMS

    Orlova A.I., Volkov Yu.F., Petkov V.I., Kulikov I.A., Zyryanov V.N., Egorkova O.V., Kemenov D.V. Nizhny Novgorod State University, Gagarin av. 23, 603600 Nizhny Novgorod, RUSSIA

    We develop concept of detoxication of nuclear waste by means of formation of phosphate ceramic It is perspective to apply high temperature methods to processing of waste of molten salt technology. Application of ceramics matrix forms provides high immobilisation barrier for waste to obtain safe storage. Crystalline NaZr3(PO4)3 (NZP) - like matrix is thermodynamically stable. Waste atoms are incorporated into the crystalline structure of matrix by isomorphous or isodimorphous substitution Crystalline product as ceramics is similar to natural minerals. Owing to peculiarity of NZP structure it is possible to form various kinds of solid state solutions. Caesium, strontium, rare-earth elements, plutonium and various 1-, 2-, 3-, 4-, 5-valent elements in wide ranges of their concentrations may be included into cation and anion sublattice of the structure. There are three types of crystallographic positions for cation occupation. As a result alkaline elements (sodium, potassium) may be included up to 40-50 w.%, too The crystalline product may be prepared as a single phase. NZP phosphates do not decompose up to 1200-1400°C and posses near zero coefficients of thermal expansion NZP phosphates are radiation stable. We did not observe any noticeable changes of chemical composition and structure either after absorption of 5-10* Gy of external y- radiation or internal absorption of 1014 a-particles/mg. Metamictisation takes place after absorption of 91O15 a-particles/mg. Composition and structure of Cs- and Sr-contaming NZP phosphates do not change at hydrothermal testing at 400°C, 600 atm during two years.

    -406- P8-16

    EXPRESS-METHOD FOR DECONTAMINATION BY USE OF MONO-IZO-OCTYL-METHYL-PHOSPHONIC ACID COMPOUNDS

    Panchenko A.V., Kashirin I.A. MosSIA ,,Radon"

    "Dry" decontamination method by use of removable polymeric coatings (RPC) has been widely distributed recently at the nuclear industry installations and in national economy. The compositions on the basis of water solution of polyvinyl alcohol, containing increased amount of surface-active compounds, glycerol as plasticiser, nitric acid and a number of specific additives are employed as RPC. The disadvantage of this method is a long period for polymeric film formation. In the case of emergency, sometimes arises a demand for immediate localisation of radioactive contamination. For this purpose express method for decontamination and localisation of radioactive wastes by use of compositions on the basis of mono-iso-octyl-methyl-phosphomc acid compounds has been developed. Express method can be successfully applied in decontamination works not only at the objects of nuclear industry, but in field conditions as well, because it is simple to operate and uses non-flammable solvents, which are widely used in industry. P8-I7

    STUDY OF CERAMICS FOR ACTINIDE WASTE FIXATION

    I.A.Sobolev, S.V. Stefanovsky Scientific Industrial Association "RADON", Moscow, Russia

    S.V. Ioudintsev, B.I. Omelianenko and B.S. Nikonov Institute of Geology of Ore Deposits, Moscow, Russia

    Immobilisation of actinides, composing an essential and the most dangerous part of High Level Radioactive Waste, into resistant forms is very actual problem. In Russia alumina-phosphate glass has been employed now as matrix form for reprocessing HLW. The glass has low stability and can be easily transformed into agglomerate of secondary crystalline and amorphous phases. As a result radionuclides can be leached by water from the matrix and released into environment. Ceramic waste forms have advantage above the glasses due to high resistence to heating, radiation damage as well as underground water influence (Ringwood et al., 1988). We have investigated U, and actinide imitators (Ce, and Gd) distribution in crystalline waste forms obtained by a melting method at SIA "Radon" experimental plant. Runs were performed in air at 1500-1700 °C and 0.1 MPa. Initial batch was composed of oxide-nitrate mixture. The materials produced were analysed by X-ray diffraction, and scanning electron microscopy. The first sample has Synroc-rype composition doped with simulated waste of "Mayak" radiochemical plant after removing (Cs, Sr) isotopes. The ceramics is composed of set of minerals, four of which: hollandite, zirconolite, perovskite, and rutile are typical to the phases in other Synroc formulations. A phase close to murataite was also present. The murataite-like mineral and zirconolite are the main uranium and cenum hosts in the ceramics. Data on partitioning of other waste elements are discussed. The other samples under investigation were zirconolite-rich ceramics specially designed for actinides, including weapon-grade plutonium, fixation. The samples are composed of the major zirconolite and minor rutile, perovskite, zirconia, aluminium titanate and residual silicate glass. Gd solubility in zirconolite reaches 33 wt.%. The following ways of the element incorporation in the phase lattice are suggested: Ca(II) + Ti(IV) = Gd(III) + Al(III), and Ca(II) + Zr(IV) = 2Gd(III).

    REFERENCES: Ringwood A.E., Kesson S.E., and Reeve K..D. // Radioactive Waste Forms for the Future, edited by W.Lutze and R.C.Ewing. North Holland, 1988. pp.233-334.

    -408- P8-18

    DECONTAMINATION OF AQUEOUS SYSTEMS CONTAINING 226Ra(ll) BY COPRECIPITATION -FLOTATION AND SOLID-LIQUID ADSORPTION

    Ligia Stoica1, D.Filip2 and Anca Razvan1 1. University "Politehnica"Bucharest, 1 Polizu St., sect.I.Bucharest, ROMANIA 2. Design and Research Institute for Rare and Radioactive Metals, Bucharest, ROMANIA

    The aqueous systems arising from the radioactive ores processing or from uranium mines require application of purifying, and especially of decontamination methods, according with the imposed limits of concentrations recommended by the International Standards. The classical methods applied for Ra(II) separation involve coprecipitation of Ba(Ra)SC>4 followed by settling down. The major disadvantages of classical methods are: long time for precipitate sedimentation (about 6-7 days) and large land areas required for settling down. Recent investigations in this area are directed to new efficient separation methods for the treatment of diluted and very diluted solutions. Among these, the separation methods by adsorptive bubbles and especially, coprecipitation-flotation represent an alternative to classical ones, due to their main characteristics: simplicity, rapidity, accessibility, good separation yield (R>95%). In this context, the paper reports results of our investigations regarding the 226Ra(II) removal from this kind of aqueous systems, by applying::

    • coprecipitation [ Ba(Ra)SO4 or Ba(Ra)CO3 ] -flotation (DAF); • coprecipitation [ Ba(Ra)SO4 ] - sand layer filtration; • adsorption on active carbon. The comparative study followed the quantitative estimation of criteria efficiencies, applied in order to attain high purification of treated solutions • 226Ra(H) ions separation by coprecipitate-flotation involves : - coprecipitation of Ba(Ra)SO4 or Ba(Ra)COj that is possible due to very close ion radii 2 2 (iBadi) = 0.143 nm and r^n, =0.152 nm); for this purpose Ba(II) and SO4 " or CO3 " have been introduced into the studied system , - agglomeration of precipitate that is enhanced by introducing an inorganic flocculent like: Al(III) or Fe(III); and separation by flotation of insoluble species that contain Ba(Ra)SO4 or Ba(Ra)CC>3 in the presence of a collector reagent, a tensioactive substance. The influencing factors have been studied; the residual 22ORa(II) content after flotation at optimum conditions was 0.006 Bq L"1.

    • Ba(Ra)SO4 separation can be achieved using a column with sand-layer having smaller size than the usual settling-down vessels Finally, the sand together with the radioactive precipitate is separated as solid radioactive residue. • The 220Ra (II) adsorption on active carbon is more suitable when large volume of waste waters with low or medium radioactive contents are involved. The experimental results obtained on radium adsorption are presented. Different types of adsorbent materials, together with the influencing factors have been studied in order to obtain maximum efficiencies The comparative study revealed the efficiency of separation by coprecipitation-flotation and the possibility of applying the selective adsorption on active carbon Both methods ensure decreasing of "" Ra (II) concentration below the limits recommended by the International Standards.

    -409- P8-19

    DEVELOPMENT OF COMBINED METHODS FOR LIQUID RADIOACTIVE WASTE TREATMENT ON THE BASIS OF DATA ON RADIONUCLIDE FORMS IN SOLUTION

    Toropov I.G., Zabrodsky V.N., Prokshin N.E., Davydov D.Yu., Efremenkov V.M.

    Purification of liquid radioactive waste is extremely important but rather difficult task. This is because their composition may often be complicated by the presence of different complexing anions, surfactants, besides, the radionuclides in radioactive streams may substantially differ by their chemical properties. The hydrolysis of cations, that is radionuclides, which may occur in aqueous solution under weak acid, neutral or basic conditions, makes the study of the physico- chemical processes taking place in such systems even more complicated. The behaviour of radionuclides in such processes as sorption, ion-exchange, solvent extraction, ultrafiltration, etc. is largely determined by their distribution between various complex forms in solution which, in its turn, depend on pH of solution, concentration of radionuclides and presence of complexing anions. The following species may form in aqueous solution as a result of radionuclide hydrolysis: hydrated complexes; mononuclear hydroxocomplexes; polynuclear hydroxocomplexes; particles of colloidal size and sediment. Besides, at present, there is some evidence of formation of mixed ligands complexes. Each of the above species has individual chemical properties not all of which are made use of in practice. Therefore, the speciation study and the study of regularities of radionuclides sorption behaviour onto different types of sorbents are necessary, in our opinion, in order to better understand extraction mechanisms and, consequently, to choose the optimum conditions for the removal of the radionuclides. For example if, according to speciation analysis, a radionuclide is in a polynuclear form in solution it can be removed just by ultrafiltration through a proper semipermeable membrane without preliminary treatment. In this work the sorption behaviour of radionuclides with respect to different sorbents was studied as a function of their form in aqueous solution. According to our results mono- and polynuclear hydroxocomplexes of some radionuclides show an enhanced sorption ability with respect to such sorbents as silicagel and zeolite. Especially interesting results were obtained for sorption of thonum(IV), scandmm(III) and uranium (VI) when the first mononuclear hydroxocomplexes were better sorbed on cation exchange resin KU-2 than their hydrated complexes. Two methods were suggested for separation of the sorbed radionuclides from purified solution - (low centrifugation and crossflow filtration.

    -410- P8-20

    REMOVAL OF 226Ra FROM LIQUID AND SOLID WASTES OF URANIUM AND FERTILISER INDUSTRY IN ROMANIA

    V.T. Vacariu, P.D. Georgescu, Rozalia Mathe Research and Design Institute for rare and Radioactive Metals, Bucharest, ROMANIA

    The Paper presents the result of research made with a view to eliminating the 226Ra from the liquid wastes originating from the extraction and processing of uranium ore as well as from the solid wastes produced in the phosphate chemical fertilisers industry. Uranium ore mining and milling is generating radioactively contaminated liquid wastes - the mine waters. These contain mainly uranium and radium. The mine waters from Romania have pH = 6.3 - 6.8. The uranium concentration in these waters is up to 10 mg/1. The concentration of 226Ra in these mine waters is varying with location, season and working intensity, available data show the maximum values to be 1.2 Bq/1. For the removal of uranium from mine waters there are already industrial plants in operation based on the use of ions exchange. For the removal of "26Ra many processes have been proposed which are based on several various methods: coprecipitation with BaCl2 in sulphate medium, ionic flotation, adsorption on different materials like coal ashes or active carbon, etc. The best results have been obtained by using the active carbon which enables decreasing the 226Ra concentration in mine waters below 0.01 Bq/1, the acidic eluate can be further concentrated by setting in a solid state as Ba(Ra)SO4 Because of the chemical-mineralogical characteristics of the Romanian uranium ores, their treatment is made exclusively by the alkaline process using solution of sodium carbonate. In final stage, a liquid waste-stock pond water results from the mud-setting pond. This waste is contaminated mainly with uranium (2-20 mg/1) and 226Rn (1-1.85 Bq/I) and it must be treated before its over-running in the hydrological basin. The pond water, because of its origin, has a basic character given by its content of sodium carbonate and sodium hydro-carbonate. For the removal of uranium, ions exchange is used. For the removal of ^Ra from the pond water methods aimed at either radium coprecipitation or its restraint on different adsorbers have been tested. The best results were obtained with active carbon of Romanian origin ensuring a reduction of radium concentration below 0.01 Bq/1. From the five chemical phosphate fertiliser plants existing in Romania, three are treating the phosphate rock by the sulphuric acid process. A solid waste, the phosphogypsum, classified because of its radioactivity as a dangerous waste, results from this process. Our studies have shown that the radioactivity of this waste is given almost exclusively by the presence of 220Ra. For its removal, studies which had in view also retrieval of sulphur have been undertaken. A technology was proposed which requires treatment of phosphogypsum with NaOH solution for the retrieval of the sulphur as a sodium sulphate, treatment of the residue with HCl for bringing 226 the Ra into the solution followed by its removal by adsorption on synthetic BaSO4. From the phosphogypsum which contains radium to a level of 2-3 Bq/1, a solution with a concentration of 1-200 Bg 26Ra/l is obtained, which may be reduced by the treatment with barium sulphate below 0.01 Bg/1 The legal standards of radioprotection in Romania limit the maximum concentration of 226Ra to 0.088 Bq/1 of water. The studies undertaken by us have demonstrated the possibilities of treatment of any radioactive wastes and their decontamination to a level required by the legal standards. The optimum parameters of the procedures are presented and the technological flow sheets for the removal of radium from these wastes are discussed.

    -411- P8-21

    MOLTEN FLUORIDE SALTS INCORPORATION IN PRISTINE AND ION-MODIFIED CARBON ALLOTROPES AND METALLIC FOILS

    Jiri Vacika, Vladimir Hnatowicz", Jarmila Cervenaa, and Ivo Peka" " Nuclear Physics Institute, Academy o/Sciencies, 250 68 Rez near Prague, Czech Republic b Nuclear Research Institute pic., 250 68 Rez near Prague, Czech Republic

    Molten fluoride salts incorporation in different carbon allotropes (such as glassy carbon, pyrolitic graphite, graphoil etc.) and metallic foils (such as Ni, Ti, Ta, W etc.), pristine and ion-treated substances, has been studied using nondestructive nuclear analytical methods, such as neutron depth profiling (NDP) and Rutherford backscatering (RBS). It was found that strong interaction of molten LiF salt with samples occurs at elevated temperature above the LiF melting point. Large amounts of Li atoms diffused into the several \xm thick surface layer, which is untypical for compact nonporous materials given above. The knowledge of interaction between liquid fluorides and tested matenals is of great interest in the framework of ADTT (accelerator driven transmutation technology) projects. ADTT technology is a promissing way toward effective nuclear wastes (such as ) liquidation. Detailed information on the interaction of working media with materials on microscopic levels is demanded for optimum choice of ADTT construction Examples of prelim/nary results on the absorption of molten LiF into different carbon modifications and some pure metals are reported.

    -A12- P8-22

    NUCLEAR REACTIONS IN THE CAVITATION BUBBLE

    Anatolij Kladov ROSLO, s.r.o., Sladkovicovo, Slovak Republic

    A new approach to the phenomenon of cavitation is proposed. The cavitation bubble can be the site of collisions of various ions and atoms with the energy of hundred millions GeV, thus exceeding the efficiency of currently used accelerators by 6 orders of magnitude. Various types of nuclear reactions in the cavitation bubble are demonstrated along with the experimental results confirming the proposed nuclear processes. Both exothermic and endothermic processes characteristic for the synthesis of nuclei are described. The fission process of nuclei into two or more fragments is also described. The process of synthesis of nuclei in the cavitation bubble accompanied with the release of energy can be considered as a prototype for industrial production of both the nuclei synthesis energy and production of various chemical elements. The process of fission of nuclei might be of great industrial importance in destruction of radioactive wastes.

    UEXT PAGE(S) left BLMiK -413- AUTHOR INDEX

    -415- Abdel-Fattah A.A. 215 Badea M. 225 Bondarkov MD. 206 Abdel-Rahim S.M. 232 Baeza A. 69, 77 Borcia CM. 134 Abdel-Rehim H. 216 BakievS.A. 171 Borisenkov V.l. 172, 173 Abou-Mesalam M.M. 396 Balakhonov V.G. 351 BorsodiA. 361,373 Abraham A. 100 BalboniG. 361 Bossus D. 143 Abuhaggar B.M. 176 Baluev A.V. 254 Bossus D.A.W. 13S Adams J.L. 242 Barandica J. 69 BoubyM. 79, 283, 321 AdloffJ.P.32 BaraniakL. 100 Brad I.I. 195 Agü'ado J.L, 164 Baranov A.Yu. 349, 363 Braithwaite A. 61 Aguete E. Carballal 274 Barnewitz H. 62 Brates G. 225 Ahl J. 348 BartonKek B. 214 Brewer K.N. 379, 386 Akhtar J. 395 Bascetin E. 292 Brown G.C. 251 AksoyA. 48, 165, 185 Bassari A. 167 Brüchle W. 242 Akyil S. 276, 290, 299 BasuniaS. 159 Brünjes F. 62 AkyüzS. 166, 167 Batrakov Ju.F. 40, 249 Bruchertseifer H. 288 AkyuzT. 166, 167, 168 Becker D.A. 128 Brunette J.P. 283 Al-Haddad M.N. 185 BeCkovâV. 319 Bubner M. 91, 107 AI-ShayeaN. 165 Beets A.L. 332 BudantsevaN.252 Albulescu L. 76 Belov A.G. 263 BugoiR. 141 Alexander C.W. 332 Bern E.M. 78 Buklanov G.V. 338 Ali A.M.I. 216,291 Bern H. 78 Bunker D. 61 Ali Z.l. Ibrahim S. 220 BenedikL. 127 Burger M. 54 Almohandis A.A. 142 Beneä P. 33, 284, 320 Burnett W.C. 257 Alonso M. Prendes 87 Berdinova N.M. 183 Bums K. 30 Allas Y. 278 Berinsky A.E. 306 Byrne A.R. 127,337 Alvarez A. Montero 211 Bernhard G. 100, 109 ÇamN.F. 158,208 Alvarez J.R. Esterez 211 BerthoX. 135 Camilo R.L. 356 AlyH.F. 216, 230,291,396 BeshewaF.H. 170 Cancio D. 77 AndrtxvA.V. 168 Bessonov A. 252 Capdevila H. 248 Andreev B.M. 309 Bestea V. 233,234 Catana D. 228, 229 Andres Y. 71 Bicer I. Özlem 403 CecalAl. 352, 394 Andreychikov B.M. 339 BichlerM. 131 Çelikdag С. 208 Andreychuk N.N. 349, 360 Bickel M. 99 CervenâJ. 148,412 Angloher G. 149 Bilewicz A. 255 Chai Chifang 28 Antoniou N.D. 192 Bilgin B. 393 Chalupnik S. 47, 56 Apostolidis С 335 Billard I. 79,283, 321 Chapyzhnikov B.A. 156 ArafaE.A. 170 Bingbin Han 256, 307 Chartroux С 294 AranaG. 129 BionL. 261 ChaudryA.M. 295 Arancibia N.L. 392 Bjomstad V. 354 CherniavskayaN.E. 389 Archundia С 325 BlaauwM. 145, 147 Cheshire M.V. 63 AshmawyL.S. 157 Bobvos /. 132 ChetverikovA.P. 172, 173 Asiani M.A.A. 276, 290 BodurN. 350 Chiarizia R. 257 Atrashkevich V.V. 186 Chiotellis E. 367 Arun G. 292, 293, 350, 393 BogdanovR.V.40,41,392 Chipara M.D. 225 Baba M. 371 BohâCik L. 73 Chipara M.I. 225 Babain V.A. 379 Bojanowski R. 55 Chisca S. 352 BacsôJ. 175 BolcalÇ. 166, 167 Chizhevskaya S.V. 389,405 Bolivar J.P. 164 -416- Chmielewski A.G. 380 Doubsk? J. 353 Feigl-Heihs M. 113 Chobola R. 296 DragusinM.218,235 Feilitzsch F. v. 149 Chongli Song 179,297,317 Drissner J. 54 Felinto M.C.F.C. 356 Chughtai N.A. 395 Droznik R.R. 238 Field D.P. 385 Chumikov G.N. 93, 183 Du J. F. Le 282 Filgas R. 92 Chung Chien 155 Dubina Yu.V. 83 Filip D. 409 Cigna Arrigo A. 24 Duksina V.V. 68, 94 FilippovE.A. 351 Cihak M. 376 Durée F. 84 FiSer M. 334, 336, 358 Cohen V.H. 356 Durecovâ A. 84 Flitsiyan E.S. 119 Collins C.H. 325 Durrani S.K. 395 Forster E. 397 Collins K.E. 325 Dyatlov A. 239 FougeronC. 135 Constantinescu B. 141 DybczynskiR. 26, 310 Fourest B. 282 Corbett D. Reide 257 Dzevitskii В.Б. 210 FrânaJ. 144 CorteF. De 126,143 Eberhardt K. 245 FrenzelE. 137 CosmaC. 81,175 Efremenkov V.M. 383,410 Fujiwaral. 340, 341 Courson 0. 286 Egorkova O.V. 406 FukudaH. 191 Czerwinski K.R. 320 Egorov Yu.V. 326, 327 Fukuda T. 103 Dädulescu E. 76 Eichler B. 245 FurukawaM. 340, 341 DamjaR.E. 176 Eismont E.A. 67, 105 Gäggeler H.W. 46 Danatikovâ E. 298 EissaE.A. 157 Garcia-Tenorio R. 164, 189 Danesi P.R. 30 EkonomoyT. 339 Gasiunas K. 153 DarabanL. 81,175 El-Abd A. 85 Gaudry A. 135 DarabanLa. 175 El-AmriF.A. 176 Gauthier-Lafaye F. 120 David F. 282, 286 El-Dessouky M. M. 231 Gavrilov V.D. 339, 349, 360 DavydovD.Yu. 344,410 El-Gabroun M.A.W. 176 Gawad A.S. Abdel 220 Davydov Yu.P. 82, 344 EI-KelanyM.215 Geel J. van 335 DegettoS. 281 El-NaggarH.A. 123 GeipelG. 109 DegmovâJ. 180 El-Naggar I.M. 396 GelsemaS.J. 147 Denniss l.S. 247 El-Naggar Z.R. 48 Georgescu I.I. 134, 196,237 DesideriD. 281 El-Tawil Abd-El-Elah A. 231 Georgescu P.D. 411 Dessouki A.M. 230 Elnimr T. 85, 232 Georgescu R. 237 DlazN. Comejo 174 Eiteren J.T. van 322, 324, 337 Gerasimov S.A. 41 Dietz M. 257 Emami M.R. 382 Germenchuk M.G. 49, 101 Dijk H.J.M. van 343 Eral M. 278, 290 Germentchuk M.G. 50 Dima V. 234, 236 Erdös E. 296 Ghafourian H. 382 Dimonie M. 225 Erees F.S. 299 Gheorghe R. 76 Erees S.F. 88 GhiblawiS.S. 176 Dmitriev S.N. 262. 263, 338, 342, Eriksen D.O. 354 Gills Т.Е. 130 405 ErmakovA. 187 Gleisberg В. 178 DmitryevS.A. 313 ErmakovA.I. 177 Gloe K. 294 DoblerJ.P. 388 Ermolaev S.V. 355 Glushko O.V. 97 DogadkinN.N. 186 Esimantovskiy V.M. 379 Glushkova V.B. 392 DoganG. 167 FaanhofA. 150 Glybin V.P. 366 Dolansky J. 320 Farazmand A. 382 Godelitsas A. 59 Doleïalovâ L. 357 Fattah A.A. Abdel 220 Goebbels J. 119 Domanov V.P. 246 FedorofïM. 156 Goeij J.J.M. de 324, 333, 337 Dong Guo-Chung 89 Fedosseev A. 252 Goetz-Grandmont G.J. 283 Doommalen J. van 322

    ^П7- GoldbrunnerT. 149 HiroseM. 191 JasmskaM. 102 Golosov V.N. 86,97 HnâtV.214 JechC.36,221,357 Goloubov B.N. 74 HnatowiczV. 148,412 Jedinâkovâ-KHzovâ V. 58,274,287 Golovanov V.l. 300,323 Hobbs R.L. 332 Jefàyri M.K. 176 Gômez I.M. Fernandez 87 Hoffinan D.C. 242 Jianchen Wang 297 Goncalves M.A. 356 HOlgye Z. 92 Jimenez A. 77 Gonzales I. Pupo 211 Honusek M. 358 Jingming Xu 259 GosmanA. 345, 357 Hooper E.W. 298, 385 Jiran R. 376 GotoY. 191 Horâk Z. 144 JiranekV. 181 GourkoO.B. 198,370 Horâkova 1. 133 John J. 279, 298, 384, 386 Gözübüyük S. 88 Horejg M. 287 Jones M.M. 43 Grass F. 139 Horn M. 294 JumaevN. 182 Gregorich K.E. 242 Horwitz E.P. 257 Junfii Liang 179, 258,259, 317 Gresitsl. 197 Hossain S.M. 159 Jurcek P. 274 Grigoriev M. 252 Houäova D. 357 KadirovaM. 182 GröneR. 180 Hradeêny C. 330 Kadlecovà 1.279 Gruia D. 76 Hradilek P. 334 Kalmykov St.N. 74 Guczi J. 120 Hsieh Cheng-Hsien 80 Kamenskaya A.N. 272 GuerraF. 281 Huang Fu-Yuan 114 Kaplan Z. 167 Guerrini R. 361 Huang Chin-Wang 80, 89, 114 KâplânnéMJ. 197 Gulea A. 394 Hübener S. 245 Karasev V.l. 360 Gunten H.R. von 29 Hughes С. 61 Karelin E.A. 360 GuoxinTian 179 Humelnicu D. 394 Kashirin I.A. 177,407 Guskina L.N. 83 Hüttig G. 122 Kassai Z. 73 Gustova M.V. 262 Hvozd"ovâ I. 345 Kazachevskiy I.V. 93,115,183,205 HabaH. 340, 341 Ibach S. 294 Kazakevich M.Z. 52 Hafez N. 398, 399 idiriZ. 184 Keceli G. 393 HanC P. 334, 336, 358 IlavskyM. 217 Kemenov D.V. 406 Hansllk E.J. 90 Ilves G.N. 326, 327 Kertész I. 361 Harangozô M. 73 Imamura M. 359, 371 KeskinovV.A.30I,306, 313 Harasimowicz M. 380 IndreiasI. 218,234, 235 KhelifiR. 184 Harding К. 385 lonescu-Tirgoviste С 194 KhiariF.Z. 165,185 Harms A.V. 324 loudintsev S.V. 42, 408 Khokhlov M.L. 98 Hassan A.M. 157 IrlweckK. 113 Kilchitskaya S.L. 65 HaäCikJ. 180 Ismail S.S. 139 Kilislioglu A. 293, 402 Hategan A. 224, 228, 229,233, 236 Ivanova N.N 97 Kiltchitskaya S.L. 67, 94 Hategan D. 224 Ivanova P. 274 Kimlenko I.M. 65, 67, 94 Hatzakis G.E. 192 Ivanova T.G. 65,68,94 Kirchner G. 62 HavranekV. 133 Iwaida T. 400 Kist A.A. 140, 209 Hegazy El-Sayed A. 216 IwasakiS. 371 Kizilcikli I. 403 Heise K.H. 91, 107, 112,397 [yengar V. 130 KladovA. 413 Hellmuth K.H. 119 Jaakkola T. 302 Klemt E. 54 Hentig R. v. 149 Jakob A. 54 Klenk T. 54 Herbst R.S. 379 JandaJ. 181 KlobesP. 119 Herrmann E. 311 Jankunaite D. 99 Knapinska-Skiba D. 55 Hilton J. 61 Janssens W. 335 Knapp Jr. F.F. 332 Hinca R. 180 Jârosi L. 197 Kobayashi K. 340 Kobayashi T. 340 Laue С. 242 Margaritescu A. 233 KodamaH. 3-81 Lauster R. 139 Marghitu S. 234, 236 Köhler M. 178 Law J.D. 379 Martin D. 218, 228, 233, 234, 235, Koch L. 335 LâznlCekM. 353 236 KohlKkovâ M. 287 LâznICkovâ A. 353 Martinez F. 303 Kolar Z.l. 37, 322, 343 Lebecka J. 47, 56 Maslennikov D.E. 40 KolarikZ. 271 Lebeda O. 334, 336 Maslov O.D. 262, 263 KolotovV.P. 186 Lebedev V.Ya. 244 Mastauskas A. 99, 153 Konicek J. 357 Lebedeva L.S. 349, 360, 363 Mateescu С 225 Kopicka K. 334 Lee D.M. 242 Mâtel L'. 60 Koprda V. 73 Legin A.V. 285 MatheR. 411 MatsudaH.T. 318 KopyrinA.A. 301,306, 313 Legin E.K. 98 MatsumuraH. 340,341 Korchuganov B.N. 339 Lehto J. 302 MatsuyamaS. 371 Korun M. 146 Leinova SX. 65, 68, 94 Matter W.S.A. 48 KöseA. 168 Leseticty L. 353, 372 Kosulin N.S. 368 Lierde S. Van 143 Matveenko I.I. 49, 50, 53, 101 Koudriashov V.P. 370 LigezaM. 193 MatyukhaV.A. 351 Koutnlk P. 372 Lima L. 303 May 1.247, 251 Kovalev A. 187 Lindberg A. 119 McGrath C.A. 242 Kovalev A.V. 177 Lindecker С 282 Mekhail F.M. 387 Kozak K. 102 LipkaJ. 180 MeliM.A. 281 KozakovS. 187 Liukkonen S. 348 Melichar F. 364 Krasnopyorova A.P. 219, 362 Livens F.R. 61 Mell P. 296 KrasnovG.l. 115 LlauradôM. 154 Menezes M.A. de Barros С 152 Kratz J.V. 242 LuShih-Changll4 Méot-Reymond S. 261 Krejbichovâ Z. 95 LujanasV. 51,99 Metwally E.M. 123 Kroon J.J. 322 LujanieneG. 51,99 Miah R.U. 159 KropâSek M.364 Lukashenko S.N. 93, 183 Michalik B. 56 KrotN.N. 266 Lukianenko M.V. 355 Mielnikow A. 47, 56 Krshishanovskaya V.A. 392 LukjanovA.V. 198 Mierzecki R. 34 KrupaJ.O. 102 Macusek F. 60,270 Mietelski J.W. 102 KfivànekM. 376 MacCordick J. 79, 321 Mikheev N.B. 52, 272 KllçerR. 166,167 Mack B. 100 MilgrantV.G. 314 KuaeraJ. 133,144,364,376 MadicC.250,261 MiligyA.A. El 215 Kudelsky A.V. 96 MaenhautW. 132 Miller R. 54 Kulich S.B. 83 Magomedbekov E.P. 309 Minea R. 225 Kulikov I.A. 406 Mahramanlioglu M. 402,403 Mioduski T. 260 Kulyukhin S.A. 52,272 Maillard С 267 Miroslavov A.E. 365 Maina T. 367 Kuznetsov G. 401 Mirzadeh S. 332 Makarenko V.A. 360 Kuznetsov R.A. 392 Misaelides P. 59 Makarov L.L. 249 Kuznetsov S.M. 300 Mishra S.P. 275,404 MakarovS.A. 188 Kvasnikova E.V. 86, 97 Miyamoto Y. 340, 341 Mamytbekov G. 217 Lacman J. 364, 376 Mizera 1.284 Manea A. 218,235 LadygieneR. 99,153 MöbiusS. 137 ManjônG. 189 Lagarde G. 282 MöbiusT.L. 137 Mardanenko V.K. 314 Langer M. 257 Moise I.V. 237 Marek M. 144 Lâszlô Zs. 373 MoisyPh. 250,261 Molinet R. 335 OhkuboT. 359, 371 Pokumejko Yu.M. 53 Molla (Fathemy) - Fathizadeh A. 201 Olivares S. 303 Pol'skijO.G. 106 Molla N.I. 159 Omelianenko B.I. 42, 408 Polyakov E.V. 326, 327 Molokanova L.G. 262, 405 Oprica M.H.I. 134 Pommé S. 129 Morariu V.V. 224, 228, 229, 233 Oproiu С 218, 224, 225, 229, 233, Pompe S. 91, 107 234, 235, 236 MoraruR. 218, 228, 235 Ponta CC. 237 Orechovska J. 277 Moreno H. 189 Popa K. 394 Orlova A.I. 406 Morozov A. 239 Popescu A. 224, 229, 233 Ostrowska M. 78 MotlA. 279, 298, 384, 386 Popescu A.S. 236 Oughton D.H. 328 MoyesL.N. 61 Popov Yu.S. 173 OuraY. 136,341 MukhamedshinaN.M. 182, 190 Poäta S. 148 Ovsiannikova S.V. 67, 96, 105 Mukhomorov V.K. 223 Preoteasa E.A. 194 OzernayaS.A. 41 Müllich U. 271 ProkshinN.E. 344, 410 Palâgyi S. 305 Muntean M.I. 196 Puchkova E.V. 40 Palamani I. 394 Muraoka S. 103 Pushkov A. 401 Palamaru M. 352 MuratovaV.M. 183 Pyartman A.K. 313 Panchenko A.V. 106,407 MusbahiA.S. 176 Qiulin Wu 256, 307 PanczykE. 193 NadirovN.N. 160 Qiuping Wang 297 Paniagua J.M. 69 Nagai H. 340 Radchenko V.M. 238, 339, 349, 360, Panin A.V. 97 363,368 Nagasaki S. 103, 264, 329, 400 PanovaT.I. 392 RadoiuM.218,234,235 NagyL. 81 PantelicaA.I. 134, 194, 195, 196 Ragotner A.M. 198 NakaharaH. 136 Papadopoulos M. 367 Rahman M. 159 NakanishiT. 191 Papadopoulos N.N. 192 Rajec P. 273, 277 Nakata K. 103 Paramonova T.I. 106 Rambusch T. 294 Naour С Le 286 Park Y.S. 309 Ramos P.L. 211 Navratil J.D. 378 Pashkevich V.l. 96 Ranga T. 296 NavratilO. 110,304,311 Paulenovâ A. 273 Rastikerdar S. 161 Negreanu B. 225 Paulus W. 242 Rauret G. 63, 70, 154,207 Nero M. Del 120 Pauwels J. 129 Ravkova E.I. 370 Nery A.R.L. 356 Река 1.412 Raybinin M.A. 339 Nesterenko V.P. 265, 366 PeltzC. 131 Razvan A. 409 Nicolai R. 91 Pershina V. 242 Regge P. De 30 Niculescu A. 229, 233 PetelinG.I. 116 Reich T. 66 Niese S. 178 Peterson J.R. 245 Remez V. 308 Nieto J.L. Martinez 345 Rencovâ J. 43 Petkov V.l. 406 Nikitenko S. 250 ftefichovâM. 217 Petrovich A.A. 96 Nikolenko S.I. 108, 116 RibalkaV. 187 Petruc С 228 Nikonov B.S. 408 RibalkaV.B. 108,116,177 Pezzin S.H. 325 Nitsche H. 57, 66, 91, 100, 107, 109, Ricardo N. Martinez 87 112,122,397 Piartman A.K. 301,306 Richardson S. 61 Nock B. 367 PiccotD. 135 Rider R. 339 NogawaN. 359, 371 PihlakA.A. 41 Rigol A. 63 NoseckU. 104 Pirmettis I. 367 Richter W. 122 NovvierH.G. 216 Pivovarov S.P. 93 Rio L.M. del 77 Ochkin A.V. 389,405 PlacekV. 214 RistoiuD. 81 Ochsenkühn K.M. 192 Plamadeala S. 234 RobouchP. 129 Ogorodnikov B.I. 99 PleshkovM.A. 313

    ^»20- Roca M.C. 70 SchönhoferF. 113 Slejkovec Z. 337 RofailN.B. 157 Schulz M. 257 SlugeiiV. 180 Roig M. 70 Sebesta F. 279, 298, 312, 315, 384, SluijsR. van 138, 143 385,386 Romanovskiy V.N. 379 Smakhtin L.A. 204, 355 Sebestovâ E. 284 Rongzhou Jiao 179,317 SmirinL.N. 183 Secu С. 225 Rosa D. De La 303 Smirnov I.V. 379 SedlakovâZ. 217 RoselliC. 281 Smith J.T. 61 SeghirM. 184 Rosenkevich MB. 309 Smröek S. 372 Seleznev A.G. 238, 368 Rossini I. 283 Smr£kovâ S. 312,384 Seleznev B.L. 285 Rubinchik S.Ya. 68, 105 SobolevA.I. 177 SenerE. 167 Rudic V. 394 Sobolev I.A. 313,408 Sepûlveda С 303 Rudnitskaya A.M. 285 Sokker H.H. 230 Serbinovich V. 187 Rufo M. 69 Sokol'sky V.V. 205 Serbinovich V.V. 108, 116 Rukhin A.B. 93 Sokolik G.A. 65, 67, 68, 94, 105 Seredavina T.A. 93 RulfkP. 319 Solodukhin V.P. 93, 160, 183, 205 SergeevA.S.40,41,392 Rumer I.A. 272 Solymosi J. 197, 296 Shaban I.S. 60 RusuC.A. 195 SortinoF. 131 Shagalova E.D. 49, 53, 101 Rutsch M. 109 Spetea M. 373 Shahpasand M. Samareh 199, 200, Ryabinin M.A. 238, 349, 360, 363, 201 Spieler P. 388 368 Shand C.A. 63 Starodub G.Ya. 338 Ryazanova L.A. 183 Sharshar T. 85 Stefanovsky S.V. 313, 389, 405, 408 Sabelnikov A.V. 263 Shaughnessy D.K. 242 Stephan H. 294 Sabino С de V. Schayer 152 Shchokin Yu.K. 50 Stepnowski P. 72, 117 Said F.I.A. 215 Shehata M.K. 123 Sterling A. 69 Sakamoto K. 340, 341 Shenber M.A. 111 Stoica L. 409 Sakharovskii Y.A. 309 ShibataS. 340, 341,359,371 StrelkoV.V. 118,314 SalageanM.N. 194,195,196 Shibata T. 359,371 Strellis D.A. 242 Salaru V.V. 394 Shimbarev E.V. 360 Strab E. 242 Salbu B. 280, 328 ShishkinS.V. 338 Stukin E.D. 86, 97, 206 SalehA.I. 170 Shishkina T.V. 338 Stursa J. 364, 376 Salmal. 132 ShklyarL. 401 Sueki K. 136 SaltanN.P. 351 Shtangeeva 1.202 Suglobov D.N. 98, 365 SalvadoriS. 361 Sidorenko G.V. 365 Suksi J. 119 SamczynskiZ. 310 Siitari-Kauppi M. 119 Suzuki A. 103,264,329 Sanchez D. Perez 174 Simoni E. 261 Svihla P. 364 Sandor Z. 197 Simonovskaya I.J. 116 Sapozhnikov Yu.A. 74 SychikovG.I. 183 Singh P.K. 43 Saritepe P. 166 Sylwester E.R. 242 Singh V.K. 275 SasD. 110 SzabôG. 120 SirajetKh. 93,115 SatoW. 136 Tanaka S. 264, 329, 400 Sirchenko l.N. 108, 116 SatohS. 359, 371 Tanaka T. 103 Skaltfan Z. 304 Sattarov G.S. 140 Tanka S. 103 Skipperad L. 328 Savushkin I.A. 198,369,370 Tarapcik P. 282 Skorobogatov G.A. 210 Sayed M.S. 398,399 Taut S. 245 Skubacz K. 47 Schausten B. 242 Taylor R.J. 247, 251 Schädel M. 242 Skwarzec B. 44, 72, 117, 203 Tchantchane A. 184 SchmeideK. 112,122 SlâdekP. 110,311 Tcharouchnikova I.A. 266 Tel H. 278 Tent J. 70, 207 UwaminoY.371 WestphalG.P. 139 TestaC. 281 Vaaramaa K. 302 Westrich. H.R. 82 Tèthal T. 330 Vacariu V.T. 411 Wieland E. 388 Thakkar A. 257 VacikJ. 148,412 Wolterbeek H.Th. 324 Tikhomirov V.A. 177 Vallejo V.R. 70 Wood D.J. 379, 386 TimofeevG.A. 172, 173 VanuraP. 316 Wysocka M. 47, 56 Timokhin S.N. 244 Varinlioglu A. 168 Xiaogui Feng 317 Tirlea A. 225 Vasilache R.A. 121 Yakushev A.B. 244 Tits J. 388 Vasile M. 225 YamauraM. 318, 356 Tiwary D. 404 Vasylevskaya T.V. 82 YaprakG. 158,208 ToaderM. 121 Vaufrey F. 261 YatsenkoV.V. 314 Todd Т.Д. 379, 386 Vedeneev M.V. 244 Yener G. 88 TölgyesiS. 197 Venault L. 250 Yermolayev I.M. 330 Tolmachyov S.Y. 262 Venke G. 339 YildizM. 167 TomaM.218,234,235,236 Verbürg T.G. 343 Yongjun Zhu 256, 259, 307 TomaäekF. 144 Vidal M. 63,70 Yongneng Zhuang 259 TömbölyCs. 373 ViereiblL. 144 Zabrodsky V.N. 344, 410 TomizawaT. 136 Viitanen P. 374 ZaCek M. 372 Török L. 296 Vincze À. 296 Zaichick V. 239 Toropov I.G. 82, 344, 410 Vioque 1. 189 Zaitseva N.G. 342 Toropova V.l. 82 Visekancev I.P. 116 Zakaria E.S. 396 Torres J. 303 Vitorge P. 248 Zakharenkov V.V. 68 Torres J.M. 154,207 Vituytnev V.M. 360 Zakrzewska-Trznadel G. 380 TôthG. 361,373 Vladimirova M.V. 222 ZamanL. 159 Tôthl. 180 Vlasov Yu.G. 285 Zänker H. 112, 122 Trautmann N. 245 Vobecky M. 35 Zauner S. 242 Trifonov Yu.I. 98 Vogtle F. 294 Zeman A. 33 Trskova R. 282 Volent G. 296 Zemplén-Papp É. 132 Tselischev I.V. 349 VolfV.43 Zheltonozhsky V.A. 206 Tsipenyuk Yu.M. 156 Volkov Yu.F. 406 Zhiganov A.N. 351 Tsoukalas С 367 Voronik N.I. 82 Zhuk L.1.209 Tsushima S. 264, 329 VoseCekV. 133 Tullock P.A. 386 VuêinaJ.L. 375 Zhukova O.M. 49, 50, 53, 101 Tuncay M. 402, 403 WalisL. 193 ZhukovichN.V. 65,67, 94 Türler A. 243 Walling D. 86 Zibold G. 54 UsmanovaM.M. 182 Wallwork A.L. 247 Zvâra I. 27, 244 UvaCikP. 180 WasB. 102 Zvaritch S.I. 64 UvirovâK. 315,384 Washiyama K. 340 Zyryanov V.N. 406