IAEA-TECDOC-409

RESEARCH REACTOR ACTIVITIES IN SUPPORT OF NATIONAL NUCLEAR PROGRAMMES

PROCEEDINGS TECHNICAA F O L COMMITTEE MEETING ON RESEARCH REACTOR ACTIVITIES IN SUPPOR NATIONAF TO L NUCLEAR PROGRAMMES HEL BUDAPESTDN I , HUNGARY, 10-13 DECEMBER 1985 AND SELECTED PAPERS FROM A SEMINAR APPLIEN O D RESEARC SERVICD HAN E ACTIVITIES FOR RESEARCH REACTOR OPERATIONS HEL COPENHAGENDN I , DENMARK, 9-13 SEPTEMBER 1985 BOTH MEETINGS ORGANIZEE TH Y DB INTERNATIONAL ATOMIC ENERGY AGENCY

A TECHNICAL DOCUMENT ISSUED BY THE INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1987 RESEARCH REACTOR ACTIVITIES IN SUPPORT OF NATIONAL NUCLEAR PROGRAMMES IAEA, VIENNA, 1987 IAEA-TECDOC-409

PrinteIAEe th Austri Am y db a March 1987 PLEAS AWARE EB E THAT MISSINE TH F GO L PAGEAL THIN SI S DOCUMENT WERE ORIGINALLY BLANK IAEe Th A doe t normallsno y maintain stock f reportso thin si s series. However, microfiche copies of these reports can be obtained from

INIS Clearinghouse International Atomic Energy Agency Wagramerstrasse5 P.O.Box 100 A-1400 Vienna, Austria

Orders should be accompanied by prepayment of Austrian Schillings 100, in the form of a cheque or in the form of IAEA microfiche service coupons orderee whicb y dhma separately fro INIe mth S Clearinghouse. FOREWORD

This report is the result ot an IAEA Technical Committee Meeting on Research Rear*or Activitie n Suppori s t Nationao t l Nuclear Programmes Budapesthel; ir d . Hungary durin3 Decembe1 0 1 g re mot-tin198bTh s . wa g e hosteCentrath y b d l Research Institut r Physicto e s (KFK1 d includean ) d participants trom ten countries, plus six trom the Technical University ot Budapes d KFKIe countriean tTh . s represented were Belgium, Finland, France, Federal Republi t Germanyo c , German Democratic Republic, India, Poland, Spain, United Kingdom, United States, Yugoslavi d Hungaryan a .

The purpose ot the meeting was to present iniormation and details of several well utilized research reactors and to discuss their contribution o nationat l nuclear programmes. Participants were invited trom countries with well developed nuclear programmes, including nuclear power programmes operatin a varietg t typeo yd powean s r level t researco s h reactors. One participant trom a reactor tacility with limited utilizatio s alswa n o invite o providt d e some insight inte reasonth o r to s the low utilization.

A related Agency activity a Semina, n Applieo r d Researc d Servican h e Activities tor Research Reactor Operations was held in Copenhagen, Denmark, during 9-13 September 1985. Selected papers trom t, s Seminar

relevan e topith t researco o ct t h reactor suppor t nation:o t ! nuclear v programmes have been include n thii d s reports hopei .iat i I dl . this report would assist reactor owners in formulating ettectiw utilization programmes. EDITORIAL NOTE

In preparing this materialpress,the International the for staff of Atomic Energy Agency have mounted and paginated the ongmal manuscripts as submitted by the authors and given some attention to the presentation The views expressed in the papers, the statements made and the general style adopted are the responsibility of the named authors The views do not necessarily reflect those of the govern- mentsMemberthe of States organizationsor under whose auspices manuscriptsthe were produced thisin The bookuse particularof designations countriesof territoriesor does implynot any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authonties institutions and delimitation the of 01 theirof boundaries The mention specificof companies theirof or products b>andor names docs implynot any endorsement recommendationor IAEA partthe the of on Authors themselvesare responsible obtainingfor necessarythe permission reproduceto copyright material from other sources CONTENTS

SUMMARY ...... 7

PAPERS PRESENTED AT THE TECHNICAL COMMITTEE MEETING ON RESEARCH REACTOR ACTIVITIE SUPPORN SI NATIONAF TO L NUCLEAR PROGRAMMES, BUDAPEST, HUNGARY, 10-13 DECEMBER 1985

Past, present and future uses of the BR2 materials testing reactor ...... 19 J.-M. Baugnet, F. Leonard Role of FiR 1 in the development of nuclear power in Finland ...... 63 HiismakiP. The role of research reactors in the development of nuclear technology in the German Democratic Republic ...... 71 . / Klebau, . ZiegenbeinD Utilizatio FRG-e th f FRG-d no 1an 2 research reactors ...... 5 8 . W. Krull Past and present uses of CEA Grenoble research reactors ...... 105 J. Garcin

Hungariae th Us f eo n WRSZ-M type research reactor Production of isotopes ...... 125 T. Lengyel Applicatio f reactor-produceno d radionuclide r industriafo s environmentad an l l investigations ...... 3 13 . K. Lehofer, T. Biro Nuclear structure studies using reactor fast neutron r (n,n'-yfo s ) reactions ...... 7 13 . A. Ver es Reactor neutron activation analysis (RNAA) ...... 9 13 . H. Rausch, A. Elek, M. Ördögh, I. Sziklai t atoHo m chemistr e researcth t a y h reactor WWRS ...... 1 15 . K. Berei, L. Vasâros Testing of structural materials in a research reactor...... 153 F. Gillemot Neutron physics...... 5 15 . M. Balaskô, L. Cser, L. Rosta, E. Svâb Educationa d researcan l h activitie e nucleath f o s r training reactoTechnicae th f o r l University Budapest ...... 163 G. Csom, F. Levai, G. Keömley Research reactor activities in India ...... 177 C.L. Thaper Research reactors contributio nationan i n l nuclear programme Polann i s d ...... 5 18 . KozielJ. (MadridN UtilizatioJE e th )f no experimenta l reactor supporn i snationae th f o t l nuclear program ...... 9 19 . V. Alcober Scottish Universities Research and Reactor Centre 205 J 4 I:att Incorporatin e operatioth g a smal f no l research reactor facilit o support y a t national nuclear power program 215 S H Li\me E S Kenne\ Nondestructive studies in metallurgy using neutrons 227 V Dimic

SFL FC FFD PAPERS FROM THF SEMINAR ON APPLIED RESEARCH AND SFRVICE ACTIVITIE RESEARCR SFO H REACTOR OPERATIONS, COPENHAGEN DENMARK, 9-13 SEPTEMBER 1985 7 23 Use f smalo s l research reactors H Rauch G Badurek F Gnus Testing oi pou er reactor fuel types in the DR3 reactor at Riso 251 P hniuhtn I Misjeldt Prompt capture gamma-ra3 26 y reference field t Imperiaa s l College 4 JMason 9 26 Neutron activation analysi e Danisth t a s h reacto 3 DR r LH (hustenden F Dannqaard New neutron scattering instruments at Riso National Laboratory A multipurpose spectrometer and the SANS facility 281 B lihecf T Fnltofti D Juul Jen\en C Broholm K Clanen L G Jen st n J K Kjems K Mortensen Research reactor as a tool for research in physics 299 K R Rao B A Dasannachana Three generations of neutron transmutation doping of silicon at Riso National Laboratory 313 K -\ndit\en K He\dom, K Hansen 5 32 Increasing utih/atio f researco n h reactors Bao \\anping Operation and utilization of the Swiss research reactor Saphrr 333 H Winkler BuhrerW Applied researc d servican h e activitie e Universitth t a s f Missouro y i Research Reactor Facility (MURR) 339 M 4lt>er D 9 34 Utilizatio f researco n h reactor t Trombaa s y S M Sundararn Increased utilizatio f researco n h reactor facilities without personnel expansioa y b n user friendly syste r routinmfo e instrumental neutro9 36 n activation analysis KorthcnenPJM PB de nun Boat M Organizatio a mediu f o n m throughput neutron activation analysis laboratorr fo y getx.hemu.dl exploration samples 379 R J Rosenherq M Lipponen L Vanska Applied research performed and in progress by using a Tnga nuclear reactor 389 4 Vloauio M Madcno The use of stable activable tracers in environmental and biological research 403 MJ Vhnski Li^-t of Participants 413 SUMMARY

An important characteristic ot all research reactors is that they e interdisciplinarar y tool a variete suse b n thai n d f differenca to y t fields: scientific research, applie r engineerino d g oriented research and training. These activities find application in medicine and agriculture as well as in industrial problems by the use ot various nuclear methods which may be cheaper, taster and better than others, and in many cases provide information not available other than by nuclear methods.

Nuclear research reactors have playe d wilan dl continu o plat en a y important role in the support of nuclear programmes. In nearly all cases, nuclear power programmes have been based largely on previous research reacto d relatean r d activities. Even those countries that have decided to buy power reactors on a turn-key basis without any significant local technical contributions and are not interested in establishing their own nuclear industry, have benetitted by working with research reactor n developini s a cadrg f scientifio e d technicaan c l personneln I . orde o makt r e decisions regardin e choicth g t reactoro e , choic f siteo e , quality assurance during construction d lateran , e problemth , f o s operatio a nuclea t o n r power plants necessari t i , o applt y y expert engineering judgement at each stage. It a country prefers to use its nationals tor this expertise rather than rely solely on foreign sources, thera stron s i e g incentiv e researcus o t e h reactore th a toor s to la s development ot this talent.

BASI APPLIEAND C D RESEARCH

e participantTh e svie th wer wt o etha a propet r utilizatiof o n research reactors in new/underutilized reactor centres can be achieved by establishing a sound programme in basic research, because this provides an understandin e fundamentath t o g l nuclear processe d techniquean s s which eventually lead to various applications ot the reactor neutrons, manpower training and related services. This programme will be more fruitfu e personth f i l s undertakin e reactoth g r utilizatio e equippear n d with fundamental knowledge coining from related existing non-nuclear research activities. Thi howeves i s t essentialno r .

Basic research include e followinth s g areas:

Reactor Physics: Experiments and calculations on flux mapping, neutro d y-dosimetryan n , burn-up data, reactivity, neutron kinetics, noise measurements, etc.

Neutron Optics: Total reflection, diffraction and interferometry.

Total neutron cross-section measurements as a function of energy wherever possible.

Detector and instrumentation development including computer applications in various areas of research.

Developmen n neutroi t n activation analysis methods.

Investigation f radiatioo s n induced effect materialsn i s .

Condensed Matter Physics: Neutron crystallography, magnetic diffraction, inelastic neutron scattering, quasi-elastic scattering, small angle neutron scattering, diffuse scattering, texture, neutron radiography.

Nuclear fission and hot atom chemistry.

Developmen f methodo t n isotopi s e production.

This list is by no means complete and a person properly trained in basic research will certainly discover new areas of research and development as has been demonstrated by researchers from several small and medium flux reactors.

e stud Th f problemo y s listed above depende availablth n o s e neutron e otheth flud r an facilitiex e particulath t a s r reactor. With high flux reactors one can take up more challenging problems in front-line areas. Basic researc s severaha h l spin-ott n appliei s d area n researci s h reactor utilization. Som t theso e e include:

Verification of codes tor tlux distribution and development ot method r parameteto s r measurement n largi s e reactors.

Material science investigations r examplfo : e textur n fuei e l rods and other materials, structural work in zeolite chemistry, microcrystallinity, catalyst d diffusan s e scatterin n ceramicsi g , internal stresses in welds, etc. by neutron diffraction; study of inhomogenieties and defects in materials such as copper clustering in steels, microporosit f coalo y l bearinoi , g rocks, cementd an s polymer studies by neutron small cycle scattering; structural disorder in nuclear fuel and other materials, dittusion in aqueous solutions, dittusion ot hydrogenous materials in open structures like zeolites, etc y neutro.b n quasi-elastic scattering d detectan ; s in nuclear tuel. embrittlement in steel by neutron radiography.

multi-element determinatio t elemento n n severai s l disciplines through neutron activation analysis.

INTERNATIONAL COOPERATION

The multi-purpose research reactor with fluxes higher than 1 x 1L001 144n/cm n/cm2s s,, liklikee tthl e materials testing reactors, have a large field ot applications.

The number ot irradiation positions available is important (up to 100 positions) and these reactors may be used tor the following purposes

tued structuraan l l materials testing (fissio d fusioan n n reactors)

safety and operational transients experiments

radioisotopes productio f higo n h specific activity ,192,. 60„ 99„ ( Ir, Co, Mo v)

industrial application (silicon doping) beam tube experiments

neutron activation analysis with high accuracy

neutron radiography

high dose gamma irradiatio y usinb n g spent tuel element.

However, the operation costs ot such reactors are quite large. In addition o react , n efficiena h t utilizatio t theso n e reactorsa , technology group is required, specialized in the design and the tabrication of irradiation devices, a dosimetry group, and a hot cell group o permit , t insertio d extractioan n t radioactivo n e materiad an l post irradiation examinations, creating in this way a complete material testing station. Complete irradiation service has to be provided from the design study to the post-irradiation examination.

o increasT e productivitth e e differenth t o y t tasks (the reactod an r its associated facilities) s importani t i , t that thea e par ar t yo t station with a recognized specialization, integrated into national programmes t possiblei d an , a par, t programmeo t s withi e frameworth n t o k international collaboration.

By international cooperation e assessmenth , e qualite th th t t o to y work conducted can be done in continuous interaction with the international scientific community and one can benefit from the much larger resources available.

By international cooperation, the use ot the high performance research reactor is optimalized and the countries which do not have such reactors have opportunitth e o havt y e acces o thest s e reactorr to s radioisotope productio t higo n h specific activity e resolutioth r to , f o n particular problems as materials testing at high flux, basic research and trainin t personnelo g A particula. r e mentionepoinb e o t tth s i d possibility to prepare beam-tube experiments at low and medium flux reactor tor later transfer to a high flux reactor.

10 RELATED SERVICES

Research reactor operation tends to create around the reactor a spectrum ot skills and equipment, which may not be available elsewhere in the country. These skills, such as handling ot radioisotopes, health physics, measuremen t verw o tactivities lo y , etc., thoug t beinno h g direct utilization ot a research reactor, can be considered as valuable resources, which should be mobilized tor the benetit ot the society. In many cases these aime besar s t achieve y creatinb d g appropriate service groups closely associated wite reactoth h r statt. Some example t suco s h related services are given below.

Applicatio t Radioisotopeo n s Outsid t Nucleao e r Medicine

By using radioactive tracers many kinds ot practical problems such as location ot leaks in pipelines, problems ot material transport, of physical processes like mixing, grinding and drying, as well as of chemical processes e ettectivelb n ca , d economicallan y y studied. Short lived radioisotopes as tracers can be conveniently produced at most research reactor r obtaineo s d trom appropriate radioisotopic generators.

Measurement ot Low Level Activities

In order to have a sutticient control of radioactive contaminations and emmisions, research reactors are provided with special equipment for measuring very low alpha, gamma and beta activities. Such skills and equipment are also needed in the environmental survey related to uranium deposits, uranium mines, nuclear power plants, etc. When considering such problems in the country, the resources at the research reactor should not be overlooked.

Health Physics t ionizingo e Us , radiatio n hospitalsi n , industr d elsewheran y e create a neesr calibratio to d t measurino n g instrument d soman s e kint o d quality assurance programmes. Research reactor centres could takn a e active rol t providino e g such services.

11 EDUCATIO D TRAININAN N G

s tacilitiee reacto s importanit th i d e t I an us r o educato t st t e persons who will have an influence on the technical, scientific and economical development ot the country. Public awareness of the benefits ot nuclear power is essential to the smooth introduction of a power programme.

e followinTh g section e communitth t o s y shoul e includeb d n plani d s tor educational programmes.

1. University, undergraduate, and post-graduate students in;

Physics Chemistry Engineering Material Sciences Lite Sciences Agriculture

2. High School teachers, who should be encouraged to include introductory material in the nuclear field in their school curriculum.

3. Publics importani t I . o spreat t d knowledge abou e benefitth t f o s nuclear power o thiT d approache.en s s shoule th e mad b do t e following:

Public officials Youth groups School groups Environmental groups Emergency planners

. 4 Emergency Personnel. Because importancth f o e t understandino e g nuclear radiation and a possible radiation incident, the military d polic an a developin n i e g country shoul e schooleb de basicth n i ds ot radiation control. They should understand the fundamentals of simple shieldin d contaminatioan g n control s obvioui t I .s thae th t research reactor centre should provide trainin r militarfo g d an y police personne o thas l t then responca y d correctl o emergenciest y ; including radiation releases or fuel security issues.

5. Medical personnel who may be called on to provide treatment in a radiation emergency.

CONSENSUS

In the early planning of the reactor, provision should be made for e traininth t locao g l instructor r educationafo s d traininan l g courses, as wel s operationa l s personnel. This will then require onl minimua y m ot external experts to be called on to provide the necessary training.

e reactoTh r e centrashoulth e b d l e educationa pointh f o t d an l training programmes s expectei t i d d an ,tha t e reactoaccesth o n t si r somy wil wa ee include b ll traininal n i d g courses e availabilitTh . a f o y simple simulator woul e valuablb d e teachinth n i e f theso g e topics.

TYPE F COURSESO S WHICH SHOUL AVAILABLE B D E

Nuclear physics neutron interactions, fission, fusion, fission products

Reactor physics reactor theory, statics, kinetics, instrumentation

Reactor engineering reactor theory, materials, instrumentation, shielding, heat transfer

Health physics detection of radiation, dosimetry, biological effects, contamination, control of radioisotopes, transporf o t radioisotopes, radioactive waste disposal

Uses of Radioisotopes industry, medicine, agriculture, hydrology and meteorology, mining

13 Neutron activation This powerful techniqu universalls i e y analysis applicable, and it is impossible to name e tieldth t l applicationo sal , e.g. agriculture, archeology, geology, life sciences, metallurgy, etc.

Radiograpy y-radiography using isotopes, neutron radiography using reactor

Environmental natural radioactivity, man-made pollution measurements

Y-radiation food, medical supplies, sterilization applications

IRRADIATIONS

Research reactor n servca s s irradiatioa e n facilities r thiFo .s purpose, the reactor itself or its spent fuels may be used as the radiation source Example t applicationo s s are:

transmutation dopin t silicoo g n (to ra develope d industrt o y electronics components) disintestat ion ot food sterilizatio t goodo n s radiation treatment ot materials (metals, plastics, etc.)

NEUTRON ACTIVATION

This metho t hig o s provee hha db intereso t d a larg n i te numbet o r fields suc s rocka hd mineralsan s , ultra pure materials, radiotracern i s metallurgy, medical biology, environmental research, etc e followin.Th g are among its advantages: the possibility of detection of most ot the isotopes through their activation; a large sensitivity; the possibility o te sampl th wor n o ke withou y physicaan t r chemicao l l modifications it ; relative simplicit s valua traininit s a ed an r yeducationa o g l tool.

Any research reactor, of a power of 100 KW or even less, with a 11 2 thermal neutro n0 1 n/cflu r moret o o x m s , constitute a ssuitabl e neutron source.

14 s associatei t I d either with prompt gamma measurement devicer o s with transfer systems between the reactor and the Analysis Laboratory which shouls neaa e reacto th e rb d s possiblea r : hydraulic rabbits wita h m/s3 ;o t e rangpneumati1 speeth t n o ei d c systems withe speeth n i d range ot 10 m/s or greater.

NEUTRON RADIOGRAPHY

y nucleaAn r reactor equipped with beam tube d capablan s t o e operating at a power greater than l kW may be useful for film-based neutron radiography t naturallyBu . e highe th ,e power th re greate,th r e sourcth e flux e morth , e convenien e e bettemethodth th e d e th ran ar st quality of radiographs.

9 A high quality radiograph is composed of some 10 quanta or registration r squarpe s e centimetr n averageo e othe th n rO hand. s a , 4 0 1 quant s a r registrationo w a te r squarpe s e centimetr e sufficienar e t to produce a recognizable image of a wide variety of everyday objects. Thuse havw n imagt a ei , e recorder wit a thermah l neutron registration 2 - 0 1 5 efficienc t 10% o s necessary i ,t i m nc y tha 0 1 t d betweean 0 1 n are incident on the image plane in a reasonable time.

The neutron beam is directed onto the sample by simply allowing it to pass through a specially constructed opening in the reactor shielding, called collimator. Collimator e characterisear s y theib dD ratioL/ r , e sourcth whers i e L eto-detecto e e widtth th r t s o hdistanci D d an e source aperture (th e collimator)e th openint e sourco th d e t en a egTh . D ratiolargeL/ e greatee th ,th r e rpotentia th wil e b l l geometric resolutio e systemth e imaget th o n :t thico s k objects wil e sharpeb l r tor improved collimation. On the other hand, improved collimation decrease e availablth s e neutron intensity.

A high quality radiograp) objeccm 0 a thic1 t r > need( to kh a higs h D ratiL/ > 200)( o , e realisewhicb n ca h W dM a reactoonle t th a y n i r range. Lower quality or radiographs ot thin objects can easily be obtaine t smala d l reactors.

Epithermal energy neutrons have been use o obtait d n improved neutron penetration ot materials that have high attenuation for thermal

15 neutrons. The increased penetration over thermal neutrons, often a factor of about 40, provides images showing internal nuclear fuel details suc s cannoa h e revealeb t y thermab d l neutrons because higheth f o re attenuation. Similar penetration advantages can be demonstrated in other materials suc s thosa h e containing hydrogen n advantagA . f resonanco e e neutrons tor radiography is the significant increase in detectability for a given material.

Significant energy tailorin f neutroo g n beam r radiographfo s s i y restricte W rangeM o reactor t de th . n i Significans t developments have been made during the last decade using electronic methods for dynamic imaging. A neutron image intensifier coupled to a television camera ensure V framT s e imagin a neutro t a g n flu W xreactorM levea a f t o A l . lower flux level, a longer integration time is necessary, but good results can still be obtained with a reactor of a tew hundred kW power level.

e mosTh t widely used application involves: - inspectio f irradiateo n d fuel - detection of hydrides in metals - checkin r faultfo g y adhesives - inspection of explosives - inspectio f somo n e metal castings - inspection of brazed joints - dynamic imaging of car engines, refrigerators, etc. - inspection of cadmium and rare earths in plates - detecting faults in neutron-shielding materials - medical samples (tumors, etc.)

16 PAPERS PRESENTED AT THE TECHNICAL COMMITTEE MEETING ON RESEARCH REACTOR ACTIVITIES IN SUPPOR NATIONAF TO L NUCLEAR PROGRAMMES, BUDAPEST, HUNGARY, 10-13 DECEMBER 1985 PAST, PRESEN FUTURD TAN E USES OF THE BR2 MATERIALS TESTING REACTOR

J.-M. BAUGNET . LEONARF , D Centre d'étude de l'énergie nucléaire, Studiecentrum voor Kernenergie, (CEN-SCK), Mol, Belgium

Abstract

The BR2 reactor (Mol, Belgium) is a high-flux materials testing reactor. The fuel is 93% 235U enriched uranium. The nominal e maipoweTh n. rfeature MW rangee 0 th 10 f so so t fro 0 6 m followine desigth e ar n: g

- maximum neutron flux x 10. therma 12 5 1. n/cm: l 2s x 10 144 8. n/cm MeV1 : 0. ) 2 s> . fas E ( t

- great flexibilit utilizatiof o y cor: n e configuration adapted to the experimental loading.

- possibilit f tailorino y neutroe th g n spectrum.

- besides the standard channels (84 mm diameter), five 200 mm diameter channel e availablear s .

The reactor is used to study the behaviour of reactor fuel elements and structural materials intended for future nuclear power station f o severas l types (fissio d fusion)an n e Th . irradiations concern performance tests up to very high burn-up or neutron fluence values on the one hand, and safety experiments, power cycling experiments d generallan , y speaking, irradiations under off-normal condition e otherth n .o s Irradiationr fo s nuclear transmutation (production of high specific activity radio-isotopes), neutron-radiography, use of beam tubes for physics studies, and pilot scale gamma irradiations are also carried out.

e papeTh r deals wite followinth h g item: s

- general introduction to the BR2 reactor,

- operational characteristics,

- neutronic aspects,

- survey of some typical experiments, already carried out or under development in support of the development of : . light water reactors, . high temperatur cooles ga e d reactors,

19 . sodium cooled fast reactors, . gas cooled fast reactors, . fusion reactors,

- possibl w featuresne e .

1. INTRODUCTION

The BR2 reactor (Mol, Belgium) went critical for the first time on the 29th, June 1961. It was put into service with an experimental loading in January 1963. On the 31st December 1978, the reacto s shuwa r t dow replaco t n berylliue th e m matrixf o l Al . e firsth td an 197hal f 9198o f 0 were devote o thit d s task. Routine operatio reactoe th s f resumeo nwa r n Juli d y 1980.

The BR2 reactor and Its associated facilities are part of the CEN/SCK Reactors Division A .complet e irradiation servicn ca e be provided, from the design study to the post-irradiation examination e operatinTh . g personner l fo f who totalo 0 8 m5 21 s the preparation and operation of the irradiation experiments and also for out-of-pile work carried out in liquid metal technology and instrumentation fields.

2. BRIEF DESCRIPTION AND SPECIAL FEATURES OF BR2

The BR2 reactor is a high-flux materials testing reactor of the thermal heterogeneous type (réf. 1,2,3). The fuel is 93Z 235U enriched uraniue for f th plateo m n i m s cla n aluminiumi d e Th . moderator consists of beryllium and light water, the water being pressurized (12.5 bar d actin)an g als s coolanta o e pressurTh . e vessef aluminiumo s I s placel i a poo d f n demineralizeo li d,an d . r e t a w

One should stress the following main features of the design :

e experimentaTh - l channel e skew ar e bundls th , e presentine th g form of a hyperboloid of revolution (see Fig. 1). This gives easy access at the top and bottom reactor covers allowing complex instrumented devices while maintainin a verg y high neutron flux e coreith n .

- Great flexibility of utilization, due to the fact that it Is possible to adapt the core configuration to the experimental loadine fissilth s a ge e centrechargb n ca n ediffereno d t experi- mental channels (Fig .show2 sa typica l core configuration).

- Although BR2 is a thermal reactor, It is possible to achieve neutron spectra very similar to those obtained in other reactor types, e.g. fast reactors f absorbino e us , e eithegth screeny b r s f fissilo e us e e materiath y ob r l withi e experimentath n l device. The neutron spectrum can be "tailored"(see Fig. 3).

- Beside4 standar6 e th s d 0 channel1 m diameter m e 4 th (8 sd an ) channels of 50 mm diameter, five 200 mm diameter channels are availabl r loadinfo e g large experimental Irradiation devices such s In-pila e sodium water o s r ,ga loops.

20 CONTROL ROD FUEL ELEMENT T turn tube

O P pool tub«

MC;, l General view of the BR2 reactor. 2 ConfiguratioBR . 2 G FI K 9 n v - 0 4 0 a in the axis of a reflector channel adjacent to the core UJ ! l - 035 H 5 23 fuea axie f th o ls n i b U! element containing 400g U -&- cadmiua n i c m screened device -^ 0 30 - in the axis of a fuel element -&

- 5 02

l spectrAl normalizee aar „ o d0 t (E)A) 0 d 1 d)(u)Au= E „ = l groupal l groups al sT - 0 2 0

- 5 1 0

0 10 -

005 -

000

10 10 ENERGYIeV !

I 1C. 3 Typical neutron spectra in BR2

l BR2 main data,

BR2 main data

Beginning of utilization 1963

Maximum heat flux

nominal 470 W/cm2

admissible 600 W/cm2

Nominal power W M 0 10 o t 0 6

Maximum neutron flux (for 600 W/cm2)

2 . thermal x 1015 2 1. n/cm s

fast (E > 0 1 MeV) x 101WcTn 4 8. 2s

Irradiation positions 0 10 o ut p

Fissile charge at start of cvcle 10 to 13 kg 235U

week* Cycl< f so e

. 1 days shut-down

. 21 days operation

Days full-power operation per year 200 to 250 3. OPERATIONAL CHARACTERISTICS

e maiTh n operational characteristic e summarizear s n i d table 1.

e reactoTh r operatio n basie opea th f s carrie-o sn i n o t ou d rating cycle e presenTh . t nominal cycle lengt4 week d s i an hs consists of 7 days shut-down for loading and unloading operations and normal maintenance work, followed by 21 days of operation ; each year o shut-dowtw , n period e extendear s r survefo d y tests and special maintenance work.

The present maximum nominal heat flux at the surface of the reactor fuel element W/cm0 47 0 W/cms 2i ,50 s 2 having been reached during special campaign 0 W/cm60 sd 2 an (programmbein ) g7C L MO e the maximum admissible heat flux (probable onse f nucleato t e boiling). The 470 W/cm2 heat flux was tested under the circum- stance f pressuro s e los0 W/cm60 s f 2incidentso havine on e g th , been tested for the nominal cooling flow rate.

e nominaTh l full-power level dependcore th e n configurao s - tion t presena use ; d t witt e i configurationth h, 11 r o 0 1 s ranges from 55 to 85 MW, the maximum reached being 106 MW. The ultimate cooling capacity, initiall s beeha n, y MW foresee 0 5 r fo n increase. MW 5 n 19712 i d o t 1

4. NUCLEAR CHARACTERISTICS

4.1. Neutron fluxes available

For a BR2 core operating at the maximum admissible heat 0 W/cm60 flumaximu e f 2o th x, m neutron fluxe: e ar s e centra th e axi th f o s l n i channe - e pluwitI B H l ga h

x . 10therma 2 11. 5 : ln/cm 2s.

- in a fuel element channel

x 10 7 . tota15n/cm1. : l 2s.

x 10MeV1 4 110. * 8. )> . fas: n/cmE ( t 2s.

MeV 0 x lO 1. 4 )1> : ^. fas E n/cm( t 2s.

Typical neutron spectra in a reflector position and in a fuel element positio e show ar nn Fig i n . 3

4.2. Capabilit r fissiofo y d fusioan n n reactor experiments

It is possible to irradiate in BR2 fissile and structural materials intende r reactorfo d f severao s l types (fissiod an n fusion y than sucwa i ) t a h irradiation effects would correspond to those expecte n thesi d e reactors.

For thermal reactor experiments (light water reactor hig, s h temperature gas cooled reactors), Fig. 3 (spectra a and b) indicates the large variety of spectra at high neutron flux level

23 availabl e reacto e fasth o thermath t n ti : er l ratio dependn o s the irradiation channel location chosen.

For fast reactor experiments, the hard spectra in BR2 can be further "tailored a certai o t " n e adoptioextenth a y b tf o n thermal neutron absorbing screen such as Cd or I^C around the experiment. An example is given in Fig. 3 showing the flux spectra in an experiment without (curve b) and with (curve c) cadmium screen located in the axis of a fuel element channel (B^C would moreover partly cut off the low epithermal neutron flux) e higTh .h fast flux contribution remains practically unaltere e adoptioth y b df thes o n e screens e y cuttinB th . f of g thermal componen neutroe th f o tn flux spectru e radiath m l fission density distributions across fuel pin bundles and inside the fuel pins themselves become much flatter (i.e. less depressed towards the centre), leadin o temperaturt g e distribution pine d th an s n i s bundles simulating better those occurring actuall n i fasy t reactors with fuel pins having high U and/or plutonium con- tents o obtaiT .e adequat th n e power rating level e 2^^th ,U 235 fractio e fueth l e f increasedb o generalln o t e s fueTh ha y.l burn-up desired can then be reached in a reasonable time. Beside e adoptioth s f thermao n l neutron screens a ,furthe r step, in large fuel pin bundle irradiations, consists in surrounding the central test a "conversionzon y b e " zono tw e ~ (e.gor e on . rows of sodium cooled fuel pins) which provoke a thermal-to-fast flux transformation.

Relatively high displacemen e tb obtaine dosen n ca i sd sample f structurao s l materials irradiate e 2 thankth BR o n t i sd high BR2 fast flux level. Also high helium formation levels can be obtained t leasa , n nickel-containini t g structural material alloys suc s austenetia h c steels e two-stea resulth s a f ,o t p thermal neutron reaction in nickel S8Ni(n,. ).. s9Ni(n,a)56Fe. Y (*) In fuel pin irradiations in BR2, on the other hand, the radiation damage doses in the cladding due to fast neutrons remain nevertheless rather limited at the end of the irradiation of fresh fuel pins when the burn-up specifications are fulfilled; it shoul e noteb d d however that irradiatio f fueo 2 l BR pin n i sn pre-irradiate n fasi d t reactor s possiblei s .

Most fusion-related experiments performed in materials testing fission o reactore t carriear t 2 ou sBR d sucs a h investigate the behaviour of first wall and other structural materials and of breeding blanket materials, submitted to high energy neutron bombardment e maiTh .n bulk radiation damages induced in these materials result from the formation of vacancy-interstitial pairs (displacements) by the highly energetic neutron-atom collision f heliuo d d hydrogean man s n gase y (n,b s d (n,paan )) reactions , thess mentione4 A . f ere n i d effect n lea o ca dimensionast d l instability (phase changes, void swelling and irradiation creep and growth) and hardening and embrittlement, manifested as changes in tensile and creep-rupture strength d ductilitiesan s , reduced fatigu d creep-fatiguan e e strengths and fracture toughness, and enhanced fatigue crack growth rates. Furthermore, hydrogen embrittlemen e firsth tf o t

24 wall structure could be induced as a result of the hydrogen forme y (n,pb d ) reaction e hydrogeth d an sn) T isotoped an D ( s injected froe plasmath m .

Irradiations in materials testing fission reactors such as BR2 of materials intended for fusion reactors suffer of course V neutronsMe 4 1 froe lac th f m.o k Nevertheless, relatively high displacemen t lowet a e obtaineb doset i r n neutroe ca sb n BR2 i d, n energies than 14 MeV, thanks to the high BR2 fast flux level. Also high helium formation e obtainedlevelb n ca s t leasa , n i t nickel-containing structural material alloys suc s austenetia h c steels, as a result of the two-step thermal neutron reaction (*) mentione dn material I pag . 24 e s containing boro r lithiuo n e th m thermal (n, i alsL 6 a) od leaan reactiono higt B e dH 10 h n i s formation rates.

A good (i.e. fusion reactor relevant) e thermadosagth f o el over fast neutron fluence ratio and hence of the appm He/dpa e ratheb rati n ca ro easily achieve 2 because greaBR th n tf i do e variety of neutron spectra available in the numerous irradiation channels. In addition of the typical spectra showed in Fig. 3 (fuel elemen r reflectoo t r position), intermediate situationn sca be obtained eithe y shiftinb r e irradiatioth g n device froe on m channe o anothert l , leadin o convenient g t time-integrated flux (fluence) shapes or, in the case of fuel element channel irradiations, by e.g. adding a water layer inside the cadmium scree n ordei n o partiallt r y rethermaliz e enterinth e g neutrons, etc. ("spectrum tailoring").

w adequatHo e appm He/dpn a i e obtaineratiob 2 BR n ca n si d the a structuracas f o e l materials irradiatio s indicatei n n i d réf. 5. This problem has been further investigated experimentally by irradiating pure Ni samples according to different histories 0 10 d exampler 2 (réfan Fo i BR na . dp ÂISn 6) .6 steei ,0 1 31 I l^ to 150 appm He can be obtained after about one calendar year of irradiatio n BR2i n.

5. REACTOR UTILIZATION

5.1. Facilities available.

At BR2, abou 0 irradiatio10 t n position e availablear s t I . is possibl irradiato t e : e

- in the pressure vessel withi- core standarth ne d fuel elements (diametef o r the experimenta) l mm o 51.cavitt 6 m m 17.: y 4

- in a driver fuel element or in a special plug m diamete m large 0 th 20 en r(i channels)

. reflector - in beryllium or aluminium plugs (diameter of the experimenta l200mmo t cavit p u ) : y - in the hydraulic rabbit self-service th n i - e thimbles.

25 - outsid pressure th e e vessel . in the beam-tubes (radial or tangential) reactoe th n i r . pool.

In addition, according to a feasibility study carried out, an experimental cavity of 400 mm diameter could be provided in the reactor central region, if requested.

Tabl 2 show ee irradiatioth s n positione neutroth d an ns fluxes availabl a typica n i e l core configuration. Fig4 show. s examples of irradiation devices loaded in a beryllium plug or a standard fuel element containin 6 plategy reducinb ; se th g number of concentric fuel plates, it is possible to increase the useful diameter of the experimental cavity. Fig. 5 gives an exampl a loo f o pe surrounde a drive y b d r fuel elemen d loadean t d in a 200 mm diameter channel.

In additioe irradiatioth o t n n 2 OperatinitselfBR e th , g Group can provide a complete high flux irradiation service from the planning stage up to the interpretation of the final results:

- assistanc desige th f experimentan o ni e l devices

- determinatio neutronie th f o n c characteristic e irradiath f o s - tion by means pf 1-D and 2-D neutron transport or diffusion codes, gamma heating calculations being also performed when required.

- desig d fabricatioan n f irradiatioo n n equipmen: t high performance loops, instrumented capsule r fissilfo s d non-fissilan e e materials irradiation t higa s h temperature d higan s h power ratings, retractable and reloadable devices, tes n pre-irradiateo t d fuel pins, power cycling devices, capsules for isotopes and transplutonium production.

- testing and commissioning of irradiation equipment.

- dosimetric analysis : determination of optimum irradiation conditions with experimental mock-up e BR0th 2 n i sreactor e zero-poweth , r nuclear model of BR2, thermal and fast neutron detector measurements.

- post-irradiation examination and analysis : dismantling of equipment, metallurgica d physicaan l lt cells testho n i s, chemical operation d analysisan s .

Example f dosimetro s y word calculationan k n connectioi s n with irradiation e give ar . n reference2 9 i n BR d n an i s 8 7, s

26 Tabl e2 Irradiation position s reactoravailablBR2 the . in e

Un configuration type 10 Power : 60 tc 83 MW M)

Maximum typical nuclear characteristics (2) .Mediation position useful diameter neutron flux (n/cm?s) Nuclear heating nuTibe) (3 r m m type thenna 1 E > 0.1 HeV W/gr. Al

- core fuee th l n elementi t t * .i s 30 to 40 17.4 to 51 6 3 8 x lO^ 7 x 1014 15 cnannm m 0 s e 20 e th n i l or 2 up to 200 - (5) 7 x 1014 13 - rerlector 2:0 nui toi es 5 o ut p 29 5 to 200 x 10,14(6 9 ) 1.3 x 1014 7 i holem 1 ' s 32 to 6 42(4 0 8 ) o t 25 9 x 4101 4 x 1012 4 5 s :>e h i m ) . 10 29 5 to 46 W C 1 x 5 1. 1 x 1013 1

jutb^Jessorp _ e eth t vess_el_

- s tjpa-e t *u n up to 305 10o t 5x101? 3 - -

- l L Jl,t Jl IJOl i i Jik, bOt->pt.3 t.,1 es 80 3 x :OL3 5 x 1012 - 0.5 7 r ïphj ü l y jd r - t t u L ' up to 200 3 x 10 - - 7 fji.1 (•lu l tit1 ' s 4 9 o 1t 2 - - rad/10 x 5r

i 1 ) U [ L i ni;- ui f lie vjrijiii ot t n L ^urt «.otifigurdti n used ard on 11 it, aptv.fu power requested i ^ ) nid •• iinuir lu it *lj-- d* t^ic surtace OT the reacLir fuel elements S05 WLT- o t L(X ) t tlonu| l t b po n io 1 1 L i i LI . L f o 1 L, 1. r u l . L t n ^ 3

t -l ) oiiL 2Ju ii n [Ji n HL l t, tjuivalt.it t^ three 8^ mn ^i.-in-cls

n e L I _ bi i , L L i i d a i IK!i L r ) C (

f 6 ) il n t«1 - ax ^ i> of • Ii r L t. H^J r" Jid-jttt" ^hdn L l s in t L teifjl cl^nnei H l l^jded ^ith bervlKun b

BR2 3e FILLING PLUG ( Crass saction) BR 2 FUEL ELEMENT { Cross section )

KiCi l .Cros s sectio a berylliu f o n m fillin a fue f go l pluelemend an g t

27 ASSEMBLB ) SU (T FUED YRO L

COOLANS GA « M I } (2

("î") GUIDIN ÜBl G E

PRIMARY CONTAINMCNl 0 t ",™IU9Oi EH l

(Y) STAGNANT H. GAS GAP

ENVELOPING PRESSURE l ©mm 6 > 1UB0 0 E( ^^. , CADMIU7 ( M iCBEEN

(J) DRIVER FUEL ELEMENT

(T; REACIOR CMiMNEL 4 !00

G.S.B. loop.Sectional view of the in-pile section

5.2. Irradiations carried out.

Purpose of the irradiations (réf.10) :

behavioue - studth f o y f fueo r l element d structuraan s l materials intended for the reactors of future nuclear power stations (sodius coolega r o dm fast reactors, high temperature gas cooled reactors, light water reactors, fusion reactors) ;

- safety in-pile experiments (particularly related o fuet n pi l coolin d transienan g t overpower r thesfo ) e reactor; s

- production of high specific activity radioisotopes ;

- basic physical research within the beam-tubes ;

- neutron-radiography in the reactor pool ;

- gamma irradiations within spent fuel element 5 xlO( s 7 rad/r o h 140 W/kg).

6. TYPICAL EXPERIMENTS

6.1. Light water reactors

Different irradiation rigs are available for testing the behaviou f fueo r l rods bein gn wate i develope e r us coole r fo d d

reactors (U02, U02-Pu02, U02-Dy203, U02-Gd2U3). The design and

28 operating feature e in-pilth f o se test sections vary from simple non-instrumented baskets to elaborated capsules allowing to reproduce typical operating condition e specimenth r fo s sa s concern rod power, cladding temperature, coolant pressure, power cycling, burn-up, etc... The irradiations are carried out in reflector channels of BR2 (réf. 11).

Table 3 lists the main characteristics of the devices used r lighfo or 2 t planneBR wate t a rd reactor fuel element development :

- the hydraulic rabbit HR for short duration irradiations (Fig.6).

P baskets e th e fue - th ,l pins being directl2 BR y e cooleth y b d primary cooling water (irradiation until high burn-up levels) .

THEBe th E- devic r thermafo e l conductivity measurements.

B capsuleCE e th s - allowing continuous measuremen powee th rf o t dissipated.

- the PWC devices, pressurized water capsules.

- TRIBULATION, irradiation of pre-irradiated LWR fuel rods in reloadable pressurized water capsules with power transients (Fig. 7 and 8) (réf. 12).

e ERATth O- compact high pressure water loor testinfo p e th g behaviou R fuePW lf o rrod s under severe power-cooling mismatch transients (under development).

Table 3 Irradiation devices for light water reactor fuel element development.

Name H R P basket THEBE L E B P W L V N S

Sanples UOj, UOz-PuO?, U02-Dv20 and U02-Gd?03 fuel pin - nature 3

- experimenter CEN/SCK, , BELGONUCEEA1RE MITSUBISHIF Ed . C E ,C hIT»CHIA , . INT. LKAE , BAHH A, , EIRI

Maximum rating W/cm 1300 820 600 700 600

Cladding tenperature „ 295 0 200 170 100 600 (maximum) or 300

Coolant water BR2 reactor water Nat. hater

Position in the reactor reflector

Special short duration - long duration thermal continuous under 1 rradiation pressure power features irradiation conducti vi ty measurement - cladding rupture 70 or c>i.l ing detection measurement of power 150 bar

Ja te of fust in adiation 1965 1963 1971 1965 1976 197'

S devicesVN e e g surroundescreer exampl^H th ri fo C , capsule e f o PW nth th dat a ey f b do ae (TRIBULATION p'-ograrrre; B N under developmen ERATe th t O cormact high pressure water loor testinfo p e behavicuth gP fuePW lf o rrod s under severe power-cooling mismatch transients

29 (»RESSUHIiER WAFER Suffi T -- REACTOR CHANNEL

" 1 2 HV 17

-© (1) T i PRESSURIZED WATER

,— . ^T^^ INIROOUC7O« l ««'UVE] CAPSULE RLC1RCULM1NG - {" ) 4, Of SAM>>1£ «VS«H T WATER THACK ) »«1ER ' OiSCHAJtOC ' > \ ®- i 1 ff \

———————————- / / ^ ———— ^ ^ ———— (^ ' VII \^ //TERMINAL //B468II -rr^ H e3 ABSORBE R SCREEN

//1RAO< JvlJ

FUEL PIN

SAMF1.E CHSCHAJtGC

SCHEMATIC FLOW SHEET

. (HydrauliHR c Rabbit) 2 COOLINBR G WATER

£CF,

^v5

FLOW ELEMENT /,

SAMPLE CARRIER

H R I Hydraulic Rabbit

o Hydraulic rabbit H.R. Schematic flow sheet i TRIBULATIO G N transient n BR2i s. Schematic outline Power Power

Time Time

8. TRIBULATION programme. Example f transiento s 2 BR n i s 6.2. High temperatur s coolega e d reactors

Since the early years of operation, the BR2 reactor was extensively used for testing structural and fuel materials conceive r applicatio fo ds coole ga e cor th f o de n i reactorsn t A . the beginning, in the years 1963 to 1969, emphasis was laid on the investigation of the behaviour of graphite samples under intensive gamma ray and neutron exposure. The tests aimed in particular at the development of the Advanced Gas cooled Reactor e higth h (AGR d temperaturan ) e DRAGON reactor. Many irradiation rigs as well as a Helium loop and a C02~loop were loaded into BR2 for studying the physical and chemical changes undergone by different kinds of graphite in a nuclear radiation field. e higTh h fast neutro x 10 7 11+ o n/cmnt flup 2(u sx abov 1 MeV0. e ) and the intensive gamma ray exposure (up to 18 W/g in graphite) availabl e centrath n i 2 efuel BR holl f o eelement s were parti- cularly attractiv simulato t e e withiw monthfe e effecta nth s f o s years of power reactor operation.

Another important irradiation programme emerged at the end e irradiatio th e sixties oth s fi t i , n testin f coateo g d fuel particles. This work was devoted to the development of fuel materials for graphite moderated reactors with high temperature cooling gas (HTR line) . The irradiation conditions offered in the BR2 core especiallar e y suite r investigatinfo d e behaviouth g f o r coated fuel particles because of the flexibility in choosing irradiation channels which allow a realistic simulation of irradiation history with respec o fast t t neutron dose, fuel burn-up, gamma ray heating and fuel temperature evolution.

Table 4 Irradiation devices for high temperature gas reactor and gas cooled fast reactor development.

Rigs Loops

Name MGR 4 8180 CPfi-MOPS CSL 1PCTL G S B

Sanp5 6 l - natjie graph 1 te AVR'pebbles" coated particles graph i te 12 vented pins

A CE KF - A A THTKF - R THTR EURATOM DRAGON-THTN CE - RU KW KF - A - experiirer rte UKAEA CEN-BN-EUR

Maxlnum rating - linear W/cm_ _ 0 50 o 5t 3 250 _ 450

- total kW - - - 20 350

Surface temperature (maximum) °C 150 to!200 1000 500 -1500 1100 60 - 0120 0 680

He p He - Ne He Cool a t He-Ne-C02 , He e h H- e 61 bar

-osition n realtor core reflector co'-e cure core core H 4

sphere of Speua' features about swept 50 capsules 60 mm creep - cadmium screen 1 rradiated diameter Lapsule

rradiatio1 t 1s Dat f o e n 1963 1966 1967 1972 1963 1977

32 Vf Ml

CROSS SECTIO PILN I EF N O PAS T

FIG.9. Cross sectioe in-pilth f o ne pard schematian t c flow sheef o t the CPR (Coated Particles Rig)

Table 4 lists the main characteristics of the devices used r higfo h2 atemperaturBR t s coolega e d reactor developmentn a s A . example, Fig. 9 shows a sectional view of the in-pile section and the flof theso we eshee on devices R f swepo tCP e t th ,loor fo p the irradiation of coated particles with measurement of fission product release rate (réf. 11).

33 6.3. Sodium cooled fast reactors

Since 1965, CEN/SCK has acquired an appreciable experience with Irradiation testin f faso g t reactor fued structuraan l l 2 reactomaterialBR e th r n d (réf13)i san .1 .1

In general the irradiation devices are either of the capsule type without coolant circulation or of the loop type with forced convection fluid cooling e presencTh .a cadmiu f o e m screes I n characteristic for most of these rigs, allowing, as mentioned in § 4.2, the filtering of the thermal neutrons and thus reducing the radial power density gradient In the cross section of the fuel bundle and individual pins to an acceptable level, typical for fast reactor conditions.

The objectives of the experiments are of various nature : - phenomenological research - parametric test d concepan s t demonstration - testin f structurao g l material specimens until high fast neutron fluence - performance and long-term endurance tests for fuel design qualification - off-normal operation and transient tests - safety related tests.

Tables 5 to 8 list the main characteristics of the devices used or planned at BR2 for irradiations concerned with the sodium cooled fast reactor development programm: e

Table 5 Irradiation devices for sodium cooled fast reactor development. Structural materials.

Name MOL 2 MCL 1 MOL 3 A MOL 3(B,F.G.H,I,K) MOL 5 MOL 20 MOL 21 OASIS

Samples concrete °2 - nature steel (allo r dispersion)o y , thermocouples, miscel laneous samples moni tors - form tensile specimens, tubes, wires, flow meters KfK - experimenter KfK and CEN CEN K f K KfK/C£N/!nteratom KfK d Interatoan K f K m

J Temperature < 100°: 600 to 700°C 400 to 70G°C 80 to 150 C «OO'C

He-Ne Na Coolant water NaK He-Ne Na or NaK He or NaK N2

Position in the reactor fuel element position gamma y fact 1 1 i

pilot continuous radiolysis sodium Special features creep high temperature irradiation creep programme experiment loop under cadmium (optional) measurement

1966 1984 t irradiatio1s Dat f o e n 1961 1984 1966 1969 1970 1982

Cladding_materlals_and_structural_materials

- MOL l : irradiations at temperatures below 100°C ; OASId an cree: S2 L p MO experiment - n tubeso ; s irradiation: 3 L MO - K n fillesodiui sNa r do m capsules (Fig.10);

34 MOL 5 : irradiation, in NaK filled capsules, of cladding samples, under stress with continuous in-pile creep measurement ; (Fig ) 11 . gamm: MO0 2 La irradiation concretf so e sample; s sodiu: 1 2 mL looMO gammr fo p a irradiatio f oxygeno n monitors,

OMP I TEMPtHATUm COKriTOL »Y HAS MIXIW3)

SS J.NVELQPING TUBE Q D 25 t

REGULATING GAS

CHOSS 5gTOF NO

FIG.10 MOL 3 device for irradiation of structural materials Tensile and impact test specimens

35 FIG. H. MOL 5 B rig. Device for irradiation of cladding samples with creep measurement

Fuel_gins

FAFNIR and FASOLD : irradiation, in NaK filled capsules, of U02-Pu02 or (U,Pu)C fuel pins under cadmium screen with central temperature or fission gas pressure measurement in several case; ) s 13 (Fig d an .2 1 CFC : in the framework of fuel cladding compatibility studies, irradiation, in NaK filled capsules, of U02-Pu02 or U02 pins with continuous measurement of the power dissipated, cladding temperature regulation and cladding rupture monitoring(Fig.14) ; CIRCE-d an 0 1 irradiation: S L MO K filleNa n d,i capsulesf o , U02-Pu02 or (U,Pu)C fuel pins with in-pile swelling measurement;

irradiation: MO2 1 L K filleNa n di , capsules U0f o , 2-Pu0r o 2 (U,Pu)C specimens with continuous in-pile creep measurement; VIC : sodium loop for the irradiation, under cadmium screen, of fresh or pre-irradiated fuel pins under transient operating conditions (cfr table 7, Fig. 15, réf. U and 15) ; FARFADE typC CF e : Tdevice s surrounde cadmiua y b d m screed an n irradiated in a core position for the study of the behaviour during start-u d earlan p R ytyp SN lif ef o efue l pins (under preparation).

36 -CX3——Ä- va MVo T

GAS SAMPUNG IN u GLOVE BOX

—tX -Ä- V 10 M V tO SV»

V 03

• VtNT

J__/Pt

CHARCOAL TRAP v IN PILE SECTION

OUTE 5 ENVELOPINR5 G tUBE O.D.25.

CADMIUM SCREEN

THERMOCOUPLES

INNE ENVELOPIN5 RS G TUBE HIGH TEXPERATUTC THEKMOCOUPL6

Irradiation position BR2 fuel elemenn VI t

CROSS SECTIO PILN I EF NO PAR T

FAFNIR 1 Fuel Array Fast Neutron Irradiation Rig)

FIG.12. FAFNIR rig. Cross sectioe in-pilth f o n e pard schematian t c flow sheet

37 CAPSULE T ÜBE 0 . !) . l 4 . ————————

FIG.13. FASOLD rig. Cross sectioe in-pilth f o ne part

38 r^^i CONNECTING MEAD "\^^*"PPESSURE CONTROL

• WASTt SV3

MY1 ¥7 u U©!:IS r-^-

MVJ

-o^-H CVI -© CV3 i

uj -^ SV2 8 -©

_B_ V TÇV COHTHOL

IN PILE SECTION

U / FILLIN R O « GB PLUG

COOLiNG WATER

CROSS SECTION 0F »«PILE PART

CFC(Compalibihty Fuel Cladding)

FIG.14. CFC device. Cross section of the in-pile part and schematic flow sheet

39 Tablée Irradiation devices for sodium cooled fast reactor development. Fuel pin irradiations.

Name FAFNIR FASOLD MM K CIRCE CFC POM CIPCE-S HOL 10 MOL 12 MOL 18 vie

Samples - nature oxides, carbides and nitrides of plutonium and uranium

- experimenter KfK-CEN-BN KfK KFA CEN-KfK- CEN-KfK EURATOM- CEN CfN KfK KfK KfK KFA l 500 (15kH/cra3) Maximum rating W/cm 600 1500 1500 1200 500 1050 500 500 (900)

Cladding Temperature uo 700°t p C

Coolant NaK matrix SAP NaK sodium

core position with cd Positio e reactoth n I nr reflector Cd screen screen

Special fission gas pressure high detection compati- high syelg in l power creep features and centra) tempe- • power of cladding bility burn-up measurement tran- rature measurement failure tests sients

Date of first 1968 1971 1968 1971 1973 1966 1976 1976 1970 1981 irradiation

under preparation : FARFADET experiment», study of the behaviour during start-up and early life of SNR type fuel rods (irradiatio n cori n e position wit screend C h )

DOUBLE WRAPPER TUBE ( He_INSIDE_ a CONTAINMENN T TUBE

ENVELOPING TUBE (Q D 445mm) r o 7.6mm 6 (0 FUE) N PI L UPWARD Na CIRCULATION

DOWNWARD Na CIRCULATION e SCREEH 3 r Nba (35mm8 3 O T 1 )

2 COOLINBR G WATER

BR2 CHANNEL 084.2mm(Be PROTECTING TUBE CADMIUM SCREEN (2.5mm

FIG.15. VIC sodium loop. Cross section at reactor mid-plane.

40 Tabl e7 Operationa l transients experiment n suppore developmeni s th f o t t of fast reactors. Main characteristic C sodiuVI e mth loopf so .

Main characteristics of the VIC sodium loop.

Since 1981 different operational transient tests have been performed on single fast reactor fuel pins. The irradiation device, called VIC a versatil s ,i e compact sodium loop which allowo tw s basic type off-normaf o s transiend lan t experiments (réf: ) .1A - fission power alteration, e.g. steady overpower ruris, power cyclin d fasan gt transient overpower (TOP); - mismatc sodiue th f mo h cooling with off-normal fuel cladding temperatures, e.g. operation with reduced sodium cooling and transient loss of flow (LOF). Both type f n transienteitheso ru e b r n separatelca s r o y simultaneously.

« IrradiatioTh s normalli n y done under cadmium screent bu , different neutron screene deployedb n ca s . Fig 5 show1 . a scros s sectioe loo t th reactoa p f o n r mid-plane e up-floTh . d downfloan w w sodium circulatio s separatei n a doubl y b d e wall wrapper tube with interna s isolationga l n integratea s A . e tesd th part f o sectiot n e screenH 3 e note on e th s, whic e absorptioh th e act n th o s f o n thermal neutrons and therefore allows to control the rod power within certain limits. Variation of the fission rate is achieved by varying the density (or pressure) of the He gas. In between the e d screescreeC *H d n optimizea an n d water volum s providei e o t d 3 allow for partial thermalization of the eplthermal neutrons and thuo enhanct s e effectivenese th H screene3 e th , f o howeves r without depressing too much the fission density across the fuel pin.

o experimentTw s have been realized wit a fresh 6 h0 ( fuen pi l an 0 7.6mmda thir d d)an experiment wit a pre-irradiateh 6 0 ( n pi d K II/KN l, origin)mm e remotTh . e encapsulatio n n activi a n f o npi e the VIC in-pile section is quite straightforward, due to its particular design (réf.15). This operation is done inside the BR2 hot cells and is followed by the sodium filling.

A broad range of transient tests can be run. For illustration, typical fast transient parameters, already being realizede ar , given : - overpower rati x nomina unde5 . o 1. d scree C r: l powen r . without Cd screen : 2.2 x nominal power - rat positivf o e e power ramping (TOP- 5Z/ 3 s: ) (unde ) Cd r - Na outlet temperature during LOF - 950° 0 C85 . pea: k level . ramping rate : 30-60 K/s

41 Fuel_bundles

e irradiationMFBth sodiu: Sr fo mW k loop ,0 unde20 s r cadmium or Cd -t- B^C screens, of fuel bundles containing up to 7 pins (U02-Pu02, UC-PuC, UN-PuN); sodiu: D d m an loop B , se irradiation 7A IPSL-50th L r MO fo W 0k , under cadmium screen and until high burn-up values, of fuel bundles containing up to 19 U02-Pu02 pins (Fig.16, réf. 16) ; sodiu: o stud t effecC e 7 a locath my W L f k loopo t MO l 0 70 s blockag sodiue th f mo e flo n bundlei w 0 fres3 r f o o sh pre-irradiated fuel pin d 18), réfan s 18 7 (Fig.L .d an .7 1

© B ASSEMBLSU FUED RO YL © SODIUM COOLANT © THERMAL INSULATION © PRESSURE TUBE © STAGNANP OA « H T © ENVELOPE TUBE © CADMIUM SCREEN 0 D 78 Î Al FILLING PLUG •X DfllvER FUEL ELEMENT REACTOR CHENAL « IX

COOLING WATER

FI6 1 GSodiu m loop IPSL-50 . Cros0kW s sectio e in-pilth f o ne part

In addition, in the frame of the European PAHR programme (Post Accident Heat Removal), three experiment e undear s r development with" the aim of studying the long-term coolability of n a initially liquid sodium saturated core debri d witbe s h internal heat dissipation s e assumei debriTh . d o havbe t sd e formed during a hypothetical severe accident in a LMFBR with partial core melting. The main characteristics of these experiment followine th e : ar s g) (Fig20 d réf, an . 19 9 1 . - core debri m diameted m be s0 11 : r - temperature : 1400, 2000 and 2900°C.

42 ladles Irradiation devices for sodium cooled fast reactor development. Fuel bundle irradiations.

Early experiments

Ha nit MFBS 1 I MKJS 2 MFBS 3 MFBS 4 M(JL 7A 6 HS eB

Experimenter A E C CEN BN GfK N C C EH

1 Samples Hunke f fueo r l pins 1 1 1 3 7 2 x 7 Diamete f pelleto r m m s 10 7 in 7 10 7 to 11 4 5 4 5 0 5 1

Nature UCd PuCan ,N UPu N U02 Pu02 U02 Pu02 U02 Pu02 uo PLU

i Man coolant Nature sodium sodium sodium sodium scd 1 jm sodium Température (maximum)°C 430 450 350 540 5bO 590 Puwer dissipated kW 60 73 93 78 195 130

3 Perforndnce of fuel pirs Specific puwer W/cm3 2200 3460 3700 <:900 2900 26uO Linear pov,er U/cn 1980 3100 3330 b7u 5'5 630 Core tenC p° rature 1400 1800 1950 2bO Burn up MWd/t 15C0 14500 112 270ÛJ 3500u 840uO

A Plug Type Al Al t 6 fuel elements typt. Ills Neutron Screen C B, Ct d Cadmi uir

5 Canpaign Start of l r radiation Oct 19o5 Ma> 96' c 19oDe 7 April 1968 s r i ci Jar 1970 Duration d 10 80 1 1ÜU 13J

Name B 7 L MO MF">S 7 MOL 7 L MOL 7 I

Experimenter N B - N CE GfK R E1 CEN Kfk CEN BN bfK CEN

1 Samples Nuribe f fueo r l pins 18 2 x 3 3J 19 Diamete f pelleto m ri s 5 1 8 5 1 i 5 H Nature U02 Pu02 UC PuC LOj an Ui tPuu JO Pul

2 Principal coolant

Nature sodium s vx uri l n sod lu SOdluT Temperature (maximumC ° ) 680 540 58 T 50 Power dissipateW k d 400 120 65C 38

3 Performance of fuel pins

Linear power W/cm585 1 ÛJÛ 410 4/ Expected burn up MWd/t 110 000 52 000 d) 75 OOu

4 n o Reactoi t \ s pa r Channel H 1 H 3 H 1 H Plug Type Al + 6 elements driver ele

5 Canpaign Star f irradiatioo t n July 19^2 April 1974 197 / (2) June 197C Duration planned d 384 300 304

(1) irradiations of shot duration (safety test local blockage of the sodium flow) (<0 the MOL 7C1 to 3 experimentr s were carried ouf respectively in 1977, 1978 and 1980 5 experiment d an M 7 sL th MO (wite e irradiatepr h d fuel pins n 198d i 198) an 3 1 under development Post Accident Heat Removal (PAHR) safety experiments

43 V. 6960

INSTRUMENTATION CONNECTOR

HEAT EXCHANGER Na-He

LOCAL BLOCKING VALVE

FIG.17. MOL 7 C sodium loop with pre-irradiated fuel bundle. General arrangemen e in-pilth f o te section

44 200mm REACTOR CHANNEL

SODIUM CONTAINMENT AND

BUNDLE, BYPASS, DOWN FLOW

WRAPPER TUBE. CENTRAL TUBE

FIG.18. MOL 7 C sodium loop. Cross section at reactor mid-plane

SAFETY TUBE PRESSURE TUBE

LOWER COOLING CIRCUIT

FIG.19. PAHR. In-pile section PIRAMID

45 6.4. Gas cooled fast reactors

From 1977 to 1982, an important demonstration project has bee s coolenga realizee e framdth th fasf o en i dt breeder reactor development programme (GCFR). The irradiation facility comprised a 400 kW in-pile helium loop "GSB", loaded with a hexagonal bundle of 12 mixed oxide fuel rods. These rods are particularly characterize a syste y r internab d fo m l pressure equalization with the main He coolant circuit and by the open venting on top of the rods of the fission gas in by-pass to the main He circuit (cfr tabl d , réfFig4 ean .5 21).

The chief aim of the programme was to demonstrate the technical feasibility and test the high burn-up behaviour of the vented GCFR fuel element under realistic irradiation conditions. Beside the many thermal-hydraulic aspects, the test facility allow o monitot s d controan r e Impuritth l d radioactivan y e contamination levels d (fissiotritiume an maith s n n ga i n) coolant and the venting circuit (Fig. 20). One dummy (HELM 1) and three fissile test bundles (HELM 2, 3, 2A) have been irradiated so far. The bundles are remotely loaded and unloaded In the in-pile section e long-terTh . m campaigburn-ua o t p f HELpu o n 3 M of 70 000 MWd/t metal has exhibited an excellent behaviour of the I n - p 11 e -section

. G.S.BFIG20 . . Loop. Flow sheet

46 loop and the fuel bundle. Experiment HELM 2A has been a short-term test on a bundle containing one rod with an artificial defect, in order to check the performance of the pressure equalization system with leaking fuel rods.

The in-pile section is still loaded in the reactor ; prolongation of the irradiation of the HELM 3 bundle is under consideration.

6.5. Fusion reactors

Tabl 9 liste maie th sn irradiation devices use r planneo d d at BR2 for Fusion reactor materials studies (réf. 22).

Structural_materials

The irradiations of structural materials take place in the e reactorth cor f o en experimenta i , 2 fuel BR cavitiel e th f o s elements.

Several of the irradiation devices designed for the sodium cooled fast reactor development programme are apt to be used for the study of the behaviour of Fusion reactor structural materials. For the irradiation of tensile and impact test specimens, the MOL 1 and MOL 3 rigs may be used. For creep experiments o kindtw ,f rigo e savailable ar s , namel e OASIth y S and MOL 5 series.

Table 9 Irradiation devices for Fusion reactor materials.

Name Purpose Dat f firso e t special features i rradiation

Structural materials

Mol l tensile and impact test specimens 1964 temperatur < e100° C

MOL 3 tensil d impacan e t test specimens 1966 200°C up to 700°C MOL 5 in-pile creep measurement 1970 OASIS creep experimen n tubeo t s 1984 FAFUMA I-M post-irradiation fatigue tests 1984 - 1985 FAFUMA III in-pile fatigue tests 1986 MAT 4 in-pile fatigue crack growth measurement under development

Breeder materials

ISOLA swept capsules with tritium recovery 19H6 G S B hel ium-cooled loop 1977

Ceramic materials

specimens of different shapes MGR 1963 temperatur o t 1200° p u e C

All these devices except the MOL l series are appropriately instrumented and equipped with temperature control systems

47 w deviceNe s have been develope e undear r o d developmenr fo t the Fusion programme n particulai , o stud t re influenc th y f o e irradiation on fatigue properties : - FAFUMA I and II for post-irradiation fatigue tests (Fig. 21, réf. 23) r in-pil - FAFUMfo I eII A fatigue tests (Fig) 22 . - MAT 4 to measure fatigue crack growth under irradiation i — -f (Fig) 23 .

FIG.21. FAFUMA I rig for post-irradiation fatigue tests

48 s inleGa t

5cm

FIG.22. Schematic view of a module for in-pile fatigue tests. FAFUMA III

49 A-A

B-B

HEAIING

i-IG. 23. In-plle fatigue crack growth. Preliminary study.

50 Solid_tritium_-_breedlng_materlals

The irradiation programme ISOLA is intended for the ^Irradiation of J5£lid Liithium Alloys and compounds in the scope of e fusioth n reactor tritium-breeding blanket technologye Th . objectives of this programme are the following :

- physico-chemical behaviou f solio r d breeders under irradiation - tritium migration and feasibility of recovery in a purging s floga w - in-pile compatibility tests (breeder materials/structural materials).

The irradiations will take plac n i swepe t capsuleo tw ; s concept f irradiatioo s n rige presentlar s y available (cfr Fig4 .2 and 25). A simplified flow diagram of the out-of-pile control equipmen s showI t n Figi n . .26

FUSION PROGRAM IRRADIATIO SOLIF NO D BREEDER MATERIALS 2 REACTOBR N I R

Four plate futl2 BR s elernenj (as shown ) «

_BR 2 Primary cooling water

Cadmium »creen (optiona| l inserted in the outer pressure tube of the capsule

Stagnant boilin; water annus u l

Breeder material envelope s showna ( D M 0 ) m m 0 3 o t p u

Helium | « Neon ) gap lpj_ temperature conlroi and. t_r Jijjm transportatiod an n recovery

Solid breeder materiaI Other capsule^ze usee b n d ca ^ ac^cordin e numbeth o f t ^o r plates in the BR2 fuel element

MG. 24. Sectional view of a water cooled swept capsule at the BR2 reactor mid-plane (Fusion Programme. Irradiation of solid breeder materials)

51 FUSION PROGRAM IRRADIATION OF SOLID BREEDER MATERIALS IN BR2 REACTOR 6- plites PR? fuel element

BR? primary cooling water

Breeder material cladding 19 2mm IG XZ1 7 min 00

Breeder material 8mm 10 /19mm OD

Central thermocouples

Peripheral thermocouples

Tritium purging gas (Helium mlet)

Tritium purging gas (Htlium outleU

Neutron fluency detectors

_____ r températurfo He/N p ga e e control

______Outer pressure tube of the capsule 22 3mm ID /?5 *.mm 00

FIG. 25. Sectional view of the helium-swept capsule at the BR2 reactor mid-plane (Fusion programme. Irradiatio f o solin d breeder materials)

FIG.26. Irradiations of solid tritium-breeding materials in the BR2 reactor. ISOLA 1. Simplified flow diagram.

52 The first irradiation campaign will begin mid-1986.

In addition, for the future application of ceramic tritium-breeding material a fusio o t sn reactor blanketa , proposed concept consists of cladded breeder elements externally cooled by helium at ~ 60 bar and internally swept by a helium flo o purg t we tritium th e . Theoretical evaluations show thaa t vented breeder element concep n reasonablca t e envisageb y r fa s a d as the tritium recovery and leakage control are concerned, on condition that an adequate oxidizing character is maintained in the coolant. With a view to the experimentation of this vented breeder element concept, it is planned to utilize the GSB helium loop designee GCFth R r programmfo d d describean e 6.4§ n i d.

Ceramic materials

Irradiation of non-breeder ceramic materials is also needed to know the mechanical and electrical changes of insulators, coating and RF-windows for fusion reactors. The target tempe- ratures are 400°C and 1200°C and the target fluence is 1022n/cm2 L MeV)O. > . SampleE f prismatica( o e ar s d cylindricaan l l form. Some discs will also be included. The samples will be put in matrices and swept by a gas-mixture. The temperature control is done by means of the control of the composition of the He-Ne gas mixture which flows between the matrices and the enveloping-tube. The materials foreseen for the matrices are graphite or aluminium e 400°C-irradiatioth r fo d niobiue 1200°C-irradiationan nth r fo m . For this kind of irradiations the past experience of irradiation, in the BR2 reactor, of ceramic materials (like graphite, beryl- lium oxyde, boron carbide, ...) with a large spectrum of tempera- tures (some hundreds degrees Celsius to more than twelve hundred) is available.

6.6. Radioisotopes production

e higth ho t therma e Du d epithermaan l l neutron fluxes avai- labl n BR2i e n ,importana t routine productio f radioisotopeo n s was established and continues with increasing interest. This production is performed by means of largely standardized irradi- ation capsule d devicean s s (réfd 24)an 1 .1

It concern e productioth s f no

0 Ci/g40 y o irradiatio)b t sp °C(u o f cobalo n t pelletr o s discs in aluminium capsules loaded in open baskets or in the reactor control rods (Fig. 27).

192Ir (up to 700 Ci/g) by irradiation of iridium pellets in aluminium capsules loaded in open baskets.

99Mo_133 Xy b eirradiation hydraulie th n i , c rabbit (Fig) .6 or the DGR device (Fig. 28), of tubes of enriched uranium clad by aluminium, similar to BR2 fuel element shells.

53 CAPSUL COBALR FO E T DISCS

COBiLI rtLLEti

CAPSULE FOR COBALT PELLETS

. FICapsule27 G r cobalfo s t irradiatio n opei n n baskets

miscellaneous radioactive isotopes, of interest for research, proces d medicaan s l applications y irradiatiob , n of miscellaneous F targetcapsuleCS n i s s e th loade n i d hydraulic rabbit, self-service thimbles D.G., pool tubes or open baskets.

6.7. Beam tube experiments

Five radia d fouan l r tangential neutron beam tubee ar s available. The loading of the BR2 core and the lay-out of the beam holes involv n a importane t fast neutro d gamman n a contaminatio e sloth w f o neutron n beams. However, experiencs ha e shown that this contamination can be eliminated by suitable varioue desigth f o ns instrumental components.

Ref. 25 and 26 illustrate the possibilities offered by BR2 as a neutron source for research in the field of Nuclear Physics e fiel th f Soli o dn i s wela ds a lSat e Physics. Several facilities are available such as a bent crystal diffraction spectrometer for gamma rays a Ge(Li, ) gamma spectrometer a tripl, e axis spectrometer, neutron diffractometers and time-of-flight neutron spectrometer n additioni ; s a ,facilit r photofo y n diffusion studies is under preparation.

54 CONTAINMENT BUILDING

TR) Q (Q)

w pressurFIG.28lo R DG e. water loop

55 1.6

u !a) = JHe control 153 5 ro = reacto) (b r power control 1.5 - (c)= föta d powero l r amplitude (a)xlb) Oi max rafe = 4tV./s "O s / . V 2 3 = e mea t a r n D Time Os start JHe blow-off V*. - Initial rod power = SI 3 W /cm a E m 1.3 -

o 124. V . a. 1.2 - "O o et 1.1 -

l 0 100V. -l 0 10 12 16 Time (s

FIG. 29. MOL 18 B 3 power transient.

7. PARTICULAR EXPERIENCE GAINED

e challenginth n I g fiel f irradiatioo d n testin f reactoo g r fuels and structural materials, thorough experience has been gained in many areas of applied sciences and technology. Parti- cular feature f thio s s experienc d know-hoan e e summarizear w d below. - Neutronic modellin d computean g r code r complefo s x geometries; dosimetry work, including full scale measurement e zerth o n i s power mock-u2 reactorBR e p th o thas BR0, f to 2 irradiation condition e adequatelb n ca s y predicted(ref.7. 9) d an ,8 - Over 20 years experience in the design, construction and exploitation of irradiation devices, and especially the know- f assemblo t ar ye e techniquesth w statgaineth ho f o en i d , in-pile instrumentation devices, advanced quality control- assurance and high performance data acquisition systems. e particulaTh - r experience e fielgaine th f powe o dn i dr tran- sient experiments and, generally speaking, irradiations under off-normal conditions (réf. 12, 14 and 17). - Saf d reliablan e e operatio f swepo n t capsules (irradiation of coated particles) and of rigs with damaged or vented fuel pins, equipped for the monitoring, handling and retention of fission product out-of-piln si e control circuits(ref.1) 21 d 6an - Re-encapsulation of prior irradiated LWR.GCFBR and LMFBR fuel pins, even int a obundl e configuration, with complex features a locasuc s a hl blockag d insertinan e, (MO) 7C Lg suc a bundlh e into the in-pile section, are now techniques mastered in CEN/SCK. A special loading machine for the remote assembly of a bundle of 30 active pins has been designed, constructed and successfull t cells(reho 2 y BR operate fe ) th 12,1 18 n i dd 5an

56 The continued know-how of sodium technology, supported by extensive out-of-pil D work R& es gaine ha , d additional expe- rience with the sodium filling of loops being loaded with pre-irradiated fuel pins(réf. 18). Tritium handling experienc e operatioa resulth s a f eo tf o n out-of-pile equipments containing irradiated 3He (réf. 27). Much experienc alss i e o availabl t celho l n i operationse , especially with the re-encapsulation of active fuel bundles and pins and with the dismantling of irradiated capsules, loops and fuel bundles. A particular experience is gained with the dismantling of the VIC loops with respect to their severe tritium contamination (neutron absorption in 3He) and the handlin f sodiuo g m circuits heavily contaminate y plutoniub d m oxides and fission products (MOL 7C loops). The long-term experience in the exploitation of the BR2 reactor d especiallan e flexibilitth y o adjust y reactoe th t r operation e individuath mod o t e le irradiatio needth f o s n experiments ha s considerably enlarged the applicability of BR2 to the more complex experimental scenario's. Examples are the reactor ope- ration at increased power level needed for the MOL 7C campaigns and the fast power ramping in support of the TOP transients with the VIC experiments. The latter feature is illustrated on Fig 9 2 whic. h show e simultaneouth s s powe e reactor th ram f o pr (124 %) with the 3He controlled power increase of the fuel pin , resultin (12) % 4a tota n i gl transient overpowe f 153.o r 5% after 16. , endes 7 y programmeb d d reactor scram a (Thi s i s typical example of a TOP transient performed with the VIC loop for the experiment MOL 18-B3). Such result requires precise synchronisatio f o differenn t operating crews, althouge th h procedur s straightforwari e d correctlan d y predictable.

8. POSSIBL W FEATUREENE S

2 developmenBR e Th t programm e adaptatio th aim e t a sth f o n irradiation capacitoperatine th d o t an y s ga conditiono s 2 BR f o s accommodat e futurth e e expected experimental loadings A . mentioned in chapter 6, several new irradiation rigs are under development. In addition, the following possible new features are under consideratio: n

provideo t e centra - th n i ,l reactore regioth f o nn experi a , - mental cavit; ym m wit 0 diametea h40 o t p u r

- to provide, in the pool of the reactor, large experimental facilities ; e increas maximue th th - t spof o emho t specific power froe th m present 470 W/cm2 level to 550 or 600 W/cm2 ;

- MOL 7C type experiments with local blockage of the sodium flow at the periphery of the fuel bundle ;

- VIC type operational transient experiments on fuel bundles ;

- PAHR (Post Accident Heat Removal) type experiments in support R safetoLW f y analysis studie; s

57 - Li-Pb capsules with tritium recovery system n suppore i s th f o t Fusion reactor tritium-breeding blanket technology programme ;

- measure o enhanct s numbee th e r (presentl f positiono ) 3 y s with high thermal neutro centrane th flu n i xl channe I (productioH l n of high specific activity radioisotopes and of transplutonium elements) ;

- a fast pneumatic rabbit for activation analysis purpose ;

a larg - e capacity irradiatio e devicth r fo e f fueo n l pins, with the abilit o load t unloay an dsamplee th d s during reactor operation ;

- measures to enhance the neutron flux in the beam tubes ;

- increasing use of the neutron beam tubes (technological and industrial applications, biology and medicine).

. CONCLUSIO9 N

The BR2 reactor was first put into service with an experi- mental loading in 1963. Since then it has contributed greatly to the developmen f mano t y large nuclear projects withi e Euroth n - pean Communit d othean y r d Japancountriean A n A .US e s th suc s a h experience of more than 20 years has been gained in the field of testing materials under irradiation.

With regard to the future utilization of the BR2 reactor, e shoulon d stres followine th s g feature: s

- high therma d faslan t neutron fluxe available ar s ; e

- neutron spectrum tailoring is possible leading to irradiation conditions correspondin o thost g e expecte n reactori d f o s several types (fission and fusion) ;

- larg d flexiblan e e irradiation space e availablar s ; e

- irradiation devices of several types can be proposed ;

- testing of pre-irradiated fuel pins and bundles is possible, including remote assembly of fuel pins in bundles and remote sodium filling of in-pile sections ;

- great flexibility of utilization : reactor core configuration d operatioan n mode adaptee experimentath o t d l loadin; g

- experienc handlinn i e g sodium circuits heavily contaminatey b d fission product; s

- tritium handling experience ;

- a complete irradiation service can be provided, from the design study to the post-irradiation examination.

58 10. REFERENCES

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(24) C.J. FALLAIS MORE. ,A WESTGAVERe Ld HEEREN. ,L , J-M. BAUGNET, J-M. GANDOLFO, W. BOEYKENS Production of radioisotopes with BR2 facilities. BR2 Reactor Review Meeting l (Belgium)Mo . Jun , 1971 e 8

(25) Research with BR2 neutron beams Proceedings of an Information Meeting Mol, November 24, 1976 P. VAN ASSCHE Editor CEN/SCK BLG 519, 1977

(26) M. NEVE de MEVERGNIES neutro2 BR f o n e beamUs n nucleai s d solian r d state physics BR2 Reactor Review Meeting l (BelgiumMo ) Jun 197, 1 e 8

(27FALL. A ) A Expérience acquise dans l'utilisatio e l'absorband n t neutronique 3He pour l'exécution de transitoires de puissance de fission. Irradiation Technology, D. Reidel Publishing Cy Dordrech Hollan- t d (19839 )43

61 ROLE OF FiR-1 IN THE DEVELOPMENT NUCLEAF O R POWE FINLANN RI D

P. HIISMÄKI Reactor Laboratory, Technical Research Centre of Finland, Espoo, Finland

Abstract The Technical Research Centre of Finland operates the FIR-1, a 2bO kW TRIGA reactor that was installed in 1962. The historical development ot the utilization ot the reactor is presented. With the introduction of nuclear power in Finland, the reactor centre has played a significant role in support ot the programme. The main fields ot activity presently are: Analytics - NAA ot some 20,000 samples per year; development ot laser resonance spectroscopy; Materials Research and Reactor Physics - mechanical testing ot reactor materials; nuclear instrumentatio d neutroan n n diffraction; Nuclear Medicin- e medical radioisotopes; Proces st radioactiv o Physic e us - s e tracers; Nuclear Waste Management.

1 Nuclea implementatiors it powe d ran Finlann ni d

Today Finland generates almost 40 % of its electricity in four nuclear power units of total capacity 2 200 WV. All générâti.ng capacity was built in ten years' period starting in 1970. The first 440 Mtf PWR unit, Loviisa 1, was connected to the national grid in 1977. The next laso tw t e units th 197n i d 9,I an uni R LoviisO BW t TV d W M an a2 0 66 s wa 198n i 0I I doublin O TV capacite gth eact y a time hth esite r beinFo . g no decisions hav beet eye n mad constructinn eo g further units.

Botnucleae hth r turbogeneratore systemth d san Loviisr sd fo an a1 Loviis wera2 e supplie Soviey db AtomenergoexporO tV/ t (AEE thed )an y are the wellknown Novovoronesh type PWR's. All the civil engineering, as well as the major part of the instrumentation and auxiliary systems includin maie gth n circulating purnps were domestic amountin abouo t g t 70 % of the total costs.

Olkiluotn i I I O oTV werd an Bote unitsR I supplie hBW O Aseab ,TV A y -db Atom, the first one on a turn-key basis, for the second one TVO itself was responsible for the civil works.

Until now the operational experiences on all four units have been very good showing loadin categorp gworlde to factorth e f th .yo f so

63 2 Organizing education, researc serviced an h nuclean i s r engineering in Finland

Unlik othey ean r industrialized country Finland never establishea d nuclear research centre, but nuclear engineering was implemented in the existing organization polytechnicaf so l character understoos wa t I . d that nuclear technology had to be developed in big countries and that the main objective of the national nuclear activities was to ensure a smooth and troublefree transfer of nuclear technology, once decisions on its implementation had to be made. From today's perspective this choicjudgee b n vers dea ca ycountra wisr fo elesf o y s tha million5 n people.

Nuclear engineering in Finland received a major impact in 1962, when FiR 1, the first and still the only research reactor went critical at the University of Technology in Otaniemi campus. FiR 1 is a TRIGA Mk II type reactor, originally 100 kW, but 250 kW since the upgrading in 1967. The main activities in the sixties were education and basic research. Small research groups were create nuclean di r spectroscopy of short-lived isotopes, in reactor kinematics and noise, in applica- tions of isotopes in industrial problems, in neutron activation analysis positron i , n annihilation irradiation ,i n damag semin ei - conductor insulatorsd san neutron i , n radiography, neutron diffraction and inelastic neutron scattering. In 1970, when the nuclear power projects started, an outstanding part of the laboratory staff were recruited both for the projects and for the licensing authority. Today they hold numerous key positions in the utility companies and in the authority organizations. By 1970 service type of activities at FiR 1 had strongly developed and were anticipated to take a dominating role also because of the nuclear power projects. That is why the Reactor Laboratory and FiR 1 were transferred to the Technical Research Centre (VTT) in 1971. The University of Technology was, however, left the educatior fo 1 capacite d R th nan Fi f o f o y% 0 3 righo t avaip o u t f lo research. Durin firse gth t seventie e yearth n si stronsa g grour pfo the development and computer running of reactor codes were created. Since 1975 this grou existes pha separata s da e Nuclear Engineering Laboratory at VTT. A separate group of experts in reactor materials was created in the Metals Laboratory as well as groups in reliability engineerin reactod an g r instrumentatio Electricae th n ni l Engineerging

64 Laboratory at VTT. Last but not least, the Department of Radio- chenu stry of the University of Helsinki should be mentioned due to educating radiochemist mane th y o researct d san h projects relateo dt the nuclear power program especially in the field of nuclear waste management.

Reactoe Th 3 r Laborator mid-eightiee th n yi s

Today the Reactor Laboratory has a staff of about 90 people, one half of which hav academin ea c degree itselT stafe VT Th .f f o amounto st whicf o 5002 0 fielhe ,20 th wornucleaf do n ki r engineering mose Th .t important facility of the Laboratory is FiR 1 reactor, the main characteristics of which are given in Table 1.

Table 1. Technical data of the FiR 1 reactor.

Type Triga Mark II, pool reactor with graphite reflector

Maximum continuous thermal W k 0 25 power

Maximum pulse power 250 MW (duratio) ms 0 n3

Maximum excess reactivit) y% 3 ( $ 4

Maximum thermal neutron flux 1 x 1013 n/Ws Fuel U + ZrHx

Uranium enrichment 20 % U-235 Fuel element cladding Aluminum or stainless steel

Core loading 15 kg U (3 kg U-235) in about 80 fuel elements

The main fields of activities are analytics, materials research and reactor physics, nuclear medicine, process physics nuclead ,an r waste management manr Fo .y application variouf so ss i field1 R sFi inevitably too weak a neutron source. In order to overcome this

65 restrictio bigge e avaio th t f d rlo n an resource economin si c way, international co-operatio bees nha n righe verifieth te b solution o dt . Example thif so s wil givee lb n below.

Analytics

FiR 1 is a quite sufficient neutron source for activation analysis. This fiel benefites dha d fronearbe mth y locatio Geologicae th f no l Survey encouraging for the development of low unit price large scale multielemental analyses for geochemistry. There are several fully automated gammaspectrometers for this purpose working 24 hours a day. Nowaday samplee sth mostle sar y activate epicadmiuy db m neutronn si order to obtain a more even activation of various elements. The number of elements analyzed is more than 50 and some 20 000 samples are analyze yearda A specia. l varian uranius ti m analysi delayey sb d neutron counting, also usegeochemistryr fo d . Several instruments have us developee n alsow or beefo d n supplie foreigr fo d n customers.

Environmental analyses have mostly bee determinane ag focusse e th n -do tion of sediments by the Pb-210 method but also on the effects of acid rain on soils and trees as well as determining the total organic chlorin environmentan ei l samples. newese Th t developmen lases ti r resonance ionization spectroscopy (RIS), whic beins i h g develope ultrasensitivr fo d e analyse tracef so r impuritie semiconductorn si biologican i d san l material- co n si operation witInstitute hth Scpectroscopr efo Academe th f f yo yo Science U.S.S.R.f so , Troitsk, Moscow.

Materials researc reactod han r physics

A hot laboratory has been built equipped with mechanical testing machines for testing activated reactor materials excluding nuclear fuel. The surveillance samples of the reactor pressure vessel steel of nucleae allth r power reactor Finlann si testee dar thin i t d sho laboratory mose Th .t important test charpy-impace sar t test, tensile test and fracture resistance test, the results of which are of vital importanc safete th n yei assessmen technicae th f to le th lif f eo reactor pressure vessels. In support of this program irradiations in a

66 material testing reacto alse rar o needed. Such irradiations have been carried out in StudsviX reactor in Sweden.

Fast neutron flufluencd an x e determination intimatele ar s y linked with the mechanical tests of pressure vessel samples. Particular attention has been devoted to the utilization of niobium for fast neutron dosi- metry due to its convenient threshold energy of about 0.7 MeV.

In reactor physics efforts have been give instrumentar fo n l development resulting at a microprocessor-based reactivity meter, now in routine uspowet ea r reactor start-ups after refuelling co-operation I . n with the Central Research Institut Physicr efo s (KFKI, Budapest)a ten-decade reactor power monitor usin neutroe gon n detector onls i y under development.

In neutron diffraction FiR 1 has been used for the development of high resolution time-of-flight techniquemechanicaa f o e us sle baseth n do Fourier chopper. Now a high-resolution powder diffractometer "Mini- Sfinks" base thin do s developmen bee s intt tha n pu o operatio higa t hna intensity neutroresearcW M 6 1 n e hguid th reacto f eo Gatchinan ri , near Leningrad, U.S.S.R. joina s ,a t project witLeningrae hth d Nuclear Physics Institute. The device seems to be very competitive in determining crystal structures excluding the lowest symmetry, with sepcial advantage in locating ordered protons.

Nuclear medicine

Routine basis irradiations for medical isotope production require a medium-flux reactor operated 24 hours a day. This is why irradiated material and in many cases ready-to-use isotope products have to be imported mosn I .t cases thes importee ear d froRossendore mth f Nuclear Centre ,gooo t GDR de ,du fligh t connection reliabld san e deliveries.

The most important products are Tc-generators, loaded in Otaniemi, instant Tc-solutions, 1-131 product nobld san e gases marketinr Fo . g these products to the hospitals a joint venture with a medical company Oriola Cy has been started.

67 Besides routine isotope productio productw nne applicationd san e sar als oclinican o developeclosn i t e pu e lus d co-operatio dan n with medical research teams. Currently cobalt-bleomycine for lung cancer diagnosi dysprosiud san m therape oolloig jointth bi r e f yso fo dar being developed.

Process physics earliese th f o te applicationOn thin si s fiel usins dwa g radioactive tracers for studying material transport and mixing in industry and surface water hydrology. There is still a lot of demand in such services, which are now benefiting from a new cesium-barium isotope generator componeny ke e th , in-sitn te i whicb o s turnet hu ha t dou calibratio flof no w transimetere th y sb t time method hydrologn I . y the most detailed information on the dilution and circulation of water in the natural or man-made basins under various weather conditions can be obtained fron mathematical models calibrate tracey db r experiments. In faconle tth y hydrological modelse ,extensivn th i whic n e i har e eus said areas in Finland have been developed at the Reactor Laboratory. Radioactive tracers have also been use mappinn di hydrologe gth f yo sitee rock th intende f so t s a d repositorie lowf s o medium-activ d -an e nuclear wastes.

Nuclear engineering methods are now being complemented by other techniques, notabl acousticsy yb . Succes bees sha n achieved especially in locating leak undergrounn si d pipe network speciaa d san l teas mi carrying out services in this field for communities and industry.

Nuclear waste management

Accordin legislatioe th o gt Finlandn ni utilitiee ,th responsible sar e for plannin executind gan g safe disposa nucleaf lo r wastese Th . governmen issues tha d fixed closing dates whicy ,b h certain milestones reachede havb o et orden I .mee o requirementre t tth utilitiee sth s have initiate dlona g term research programanagemene th n mo d tan disposal of nuclear wastes. VTT is broadly participating in this program. There are many projects going on at the Reactor Laboratory aimin deepet ga r understandin lone th g f tergo m physico-chemical processes, which take wast e placth en e i produc t itselfothen i d r,an

68 engineere naturan i wels da s la l barriers. Thereby relevant material datcompilee aar usee b computen i do dt r models underlyin overale gth l safety assessments. International oo-operation has been established with other Nordic countries and with the Karlsruhe Nuclear Centre, FRG. Part of the work in this field aims at helping the licensing authori- tie thein si r worjudginr kfo licensabilite gth utilite th f yo y plans.

69 THE ROLE OF RESEARCH REACTORS IN THE DEVELOPMENT OF NUCLEAR TECHNOLOGY GERMAE INTH N DEMOCRATIC REPUBLIC

J. KLEBAU, D ZIEGENBEIN Zentralinstitu r Kernforschunfü t g Rossendorf, Akademi r Wissenschaftede e r DDRde n , Dresden, German Democratic Republic

Abstract The GDR operates 5 research and training reactors: RFR, a 10 MW light water cooled and moderated reactor of the Soviet WWR-S type; RRR a zero power Argonaut type; RAK a lighE t water moderate d reflectean d d tank type; ZLFa R W tan W soli0 1 l k a typed R homogeneouAK ; s type. Activities include reactor physics, neutron diffraction, radioisotope production (40,000 packages per year), silicon transmutation doping, education and training. A computer based reactor control system is also described.

1. Introduction

The developnent f njeleao , s beeha r nR technolog starteGD e th n 19y i tb n R 5i y e conclusioth A governmenta f o n l agreemen e support th betwee n o t R nGD USSd an R e developmenth t a R of GD nucleafo t r research a resul /1/s A .f thi o t s agree- ment several nuclear research device e USSRsth wer.y b eR delivereGD e th o t d The ye foundatio werth e basi th r e Centra fo th s f o nl Institut r Nucleafo e r Research (CINR) in Rossendorf near Dresden in 1956. In e "Rossendorfe195th 7 r Forschungsreakto rt int (RFR)pu o s operationwa " . It is a light wiler rooled and moderated reactor from the Soviet WWR-S type. To satisfy the growing demands of irradiation capacity its power was raised from 2 MW to 10 MW in the sixties.

In e "Rossendorfe196th 2 r Ringzonenreaktor (RRR) a "zer o power reactof o r Argonaut type and in 1969 the "Rossendorfer Anordnung für kritische Experi- mente (RAKE)" have been develope t intpu o d operatioan d e CINRth n .i n At the end of the seventies further zero power reactors the AKR developed d installean e Technischth t a d e Universität e ZLFDresdeth R d developean n d and installed at the Ingenieurhochschule Zittau became critically for the first time.

Utilizatio f nucleao n r energ r generatiofo y f electricito n s startewa y n i t e beginnin th e sixties n th i f R tho g GD e. capacita Unti w . no l f 183W o yM 0 based on reactors of the Soviet WWER type has been installed in Nuclear Power Plants totae .th Thilf o adequats volum i s% 8 existinf o eo t e g power plants.

71 Tabl give1 e a e survesresearc th n o yd powe an h r reactors installee th n i d o t now GDp u .R

Tabl 1 e Operating nuclear reactor e GDth Rn i s

name place year of thermal power electrical commissioning

Rossendorfer Forschungs- CINR Rossendorf 1957 2 10 MW leaktor (RFR)

Rossendorfer Ringzonen- 1962 50 W reaktor (RRR)

Rossendorfer Anord- 1969 10 W nunr kritischfü g e Experimente (RAKE)

Ausbildungsreaktor der DJ esden 1978 1 W U DresdeT n (AKR)

Lehr d Versuchsreaktoun - r Zittau 1979 10 W der IHS Zittau (ZLFR)

KKW Rheinsberg (HVER-2) Rheinsberg 1966 W M 0 26 70 MW

KKW Greifswald-Lubmin (WWER-WO) Block 1 Lubfiun 1973 1375 MW <4iO MV Block 2 - " - 197<* - " - - " - Block 3 - " - 1977 - " - - " - Block n - " - 1979 . . .

. Researc2 d Traininan h g Reactor e GDth Rn i s

2.1. Rossendorfer Forschungsreaktor (RFR)

The RFR is a research reactor of the Soviet WWR-S type /2/ /3/- The most important parts of the reactor are housed in a cylindrical aluminium tank of 2.25 m diameter and 5-5 m height. Inside of this protective tank is e so-calleth d reflector tank wit e separato th e hcore th d . an rBot h tanke ar s filled with water to a height of about 5-0 m.

For neutron beam research there are nine horizontal beam holes and one thermal column.

72 e orig:nalyTh used EK-10 fuel elementm c 1 m lonsc d havan 0 ge shap5 th e f o e 235 thick rods containing uranium dioxidf o 6 1 e . pellet"U f so enriche% 0 1 o t d these rods were combine a fue o L ld assembly e criticaTh . e lreacto th mas f o sr was about 3•2 kg U. The maximum thermal power of 2 MW was corresponding to an average thermal neutron flux of 1 10 n cm s e e middlsixtieth th a firsf n o n I ei st ste f reconstructioo p e poweth n r coule b d raised up from 2 MW to 4 MW. This was possible alone by the improvement of the heat transfer connected with increasing roughness of fuel rod surface. Small groves with a depth of 0.25 mm and a distance of 0.5 mm between them : n e outsidth e aluminium n improvemena claddin o t e head th le gtf o ttransfe r coefficient for a factor of 2.

n 196 I e secon7th dc onstructio re ste f o p s realizewa n e mucy usinb th dh f o g more efficient modified fuel elements froe ECH-th m 1 type originally developed for the Soviet WWR-M type reactor. This new fuel elements have an active length 235 d contaian m c o nf0 6 uraniufue f o l f mo enriche% 5 3 o t d n connectioI . U n wite beryliuth h m made reflecto e criticath r l mass coulg k e reduce6 b d 1. o t d 235 U. Simultaneously the reactivity reserve needed for realization of irradia- tion channel s increasedwa s . Fig 1 show. e modifieth s d ECH-1 fuel assembl e d crosFigth an y .2 s sectiof o n the reconstructed WWH-S core.

l assemblue I Fie1 ) y ECH-1 1 -- (mcmbly holder. 2 — interior fuel element, 3 — triple assembly, 4 — U-Alj-disperiion, 'j — aluminium clodding. 6 — aluminium cladd- g ing. / -- lucl ttjbcs

73 .Ji AI-Rpflek1cr

Be-Reflektor

Pneumatische BestraMungscnlage

Bestrohlungs -can ci l

Al-RefleKtcm i ' A r Therm B. im Be-Reflekic,- Säule Corm i C e D Drehkana; HF HochMuflkanal j Absorberpo(f icI bn BerylliumverdrangeO r

Kontainer Becher Reakfordusche

Fig. 2 Cross section of the RFR core

Special devices developed for automation of loading and unloading operations enabl e reactoth e r staf o meef steadilt f th t y growing requirement f voluminouo s s productio f radioactivo n e isotope f neutroo d an sn dotted cilicon. -2-1 e applicablTh e maximum neutron flus i x x 10 n cm r thermafo d an l -2 -1 m c n 0 " x ? . 1 r fasfo t neutrons s

2.2. Rcssendorfer Ringzonen-Reaktor (RRR)

The RRR is a zero power reactor af Argonaut-type A/. It is light-water moderated and graphit reflected. The core is a cylindrical ring with a thickness of 15 cm and an inner diarreter of 60 cm. Inside of this ringzone maximal 24 fuel elements between which graphit is arranged can be inserted. One fuel element can consist 2 sectionso1 f , wit 6 hfue l rods insid f eaco e h section e e corheighTh th .e f o t is 60 cm. Uranium oxyde (U 0,) enriched to ?0 % serves as fuel. Outside the ringzon s surroundei e a graphi y b d t reflector e interioth n I . r different mate- rials for instance graphit or fuel compositions can be inserted in dependence on the reactorphysical experiments which are of interest (see Fig. 3)-

74 o o

1 thermal ring zone 2 outer graphit reflector 3 graphit reflector or fast lattice i control rods 5 safety rods 6 neutron source

Fig 3 . Horizontal cross R sectioRR f no

Since 1972 the RRR became a coupled fast-thermal system by the insertion of •i fa.st. lattice (SEG) into the interior. This fast lattice can be realized by configuration of different, materials and fuel of different enrichment in dependence on the aims of the experiments /^/.

Rosseridorfer Anordnun r kritischfü g e Experimente (RAKE)

The RAKE is a light water moderated and light water reflected zero power reactor e tanoth fk type /6/. Main components are:

e reflectoth - r tank, - the cylindrical central tank containing the core with a diameter of 60 cm e uppeth r- biological shield an d - the combined control and safety devices located in the centre and at the edge of the core.

e structurTh e corth ef o eessentiall y correspond e structurS th H o t WW s f o e cores, because in the RAKE the same fuel rods from EK-10 type will be used. Very flexible structure of the core is needed to realize the different experiments. Therefore, the fuel rods are not combined to fuel assemblies but installed separatly (see Fig . Besides.4) e splitteb e corn th ,ca e d into different sections.

75 p GG\ q / p P o o o^öVb o o o o o 0 o © o o o\ OOOOO0Ö0ÖOOOG O/ P P p O G G // N \ ^o c o P Q o/o oooooopooöooo QOOOOOOQOOOOOP G/ G o/pG o O o0 O oooooooooooo >c0 0^ ( o n ? c; ooo o/c^ègo oooopoooooooc O/OgÖSGPO G O CO p OOOOOPOOOO OO G O O G Q 0/ngOgOQO 0000000 O P oQ > O 'P G O G/CSCSO (TQ O O O/O O O P\O O O O C O P G G O/O O°O O O O O O/O OOO O\O O O Q @ O P.-Ö p G/O O O O O G O O/O®G OAO O®O\O/O O 0 (! Q PXG O O O O O P O

T.r 1 J « (<<>utlxla

s possibli Bt yi thio y instalt ewa s l channel r otheo s r experimental devices t nearla e corey placth an y f A specia.o e l vertical channel wit a maximuh m e ralizeb e e centrcore th th n t wiln f ca I .i o d e speciall m b ldiametem 0 11 f yo r needed for pile oscillator experiments.

e maximuTh m therma lwhicW e reacto powe0 th 1 h f s o ri correspondr thermaa o t s l i „' o _ flu f aboun o x 0 1 t in the centre of the core.

2.4. Zittauer Lehr Forschungsreaktod un - r (ZLFR)

The ZLFR /?/ is a tank-type reactor with a thermal power of 10 W (neutron flux i _ o _ o 2 x 10 n cm s ). The core is cylindrical and composed by fuel assemblies of the modified ECH-1 type which were developed for the reconstructed RPR in

76 the CINR. The loading of the core consist of 91 BCH-1 assemblies used as single or so-called triple units. This fuel elemen e advantagetth typs ha e , that thin probe r measurinfo s e in-corth g e neutro e insertenb flun ca x d inte interioth o r fuel tube.

Fig. 5 shows a cross-section through the ZLFR reactor. e safetTh d (bororo y n carbide s locatee a watee i )corcentr th n th i ef rn o i ed filled channel. The three control rods in dry channels at the edge of the core consist of cadmium sheets as neutron absorber. The neutron source is automati- cally removed from the core after a shutdown.

Fig.5 Cross sectio e ZLfth f Rno core 1 — safety rod, 2 — fuel assembly. 3 — neutron source. 4 — free position, 5 — tan- gential channel cor— e6 . vessel eiperimenta— 7 . l channel arrangemen— 8 , t OI/3, contro— 9 l fissiorod— 0 1 , n chamber

The tangential and experimental channels are used for the investigations in radiation protection and reactor physics. The critical mass is 3-5 kg

2.5- Ausbildungs- und Forschungsreaktor der Technischen Universität Dresden (AKR)

Fig. 6 shows the construction of the AKR /8/. It is laid out for a power of e cylindricaTh . ) s W (neutro1 l a diamete m corc s eha 0 nf 1 o r flu x 5 x 1 - 2 - 7 a critica consistt d I an . m mm lf m separat o s 5 heigh 0 27 25 f o et plateformed fuel element f differeno s t5 mrn 2 thicknes o )t whicm m e upoe pileon 2 ar hn( s p u d

77 T'

1 r'r JL^ W' •** | T ' " b t

Fig.6 Cross K sectioAR f no

the other. The fuel elements consist of a homogenous dispersion of polyethylen d uraniuan m jxyde wit n enrichmena h . Thee % coate ar y0 2 df c t with pure polyethylen.

For safety reasons the core consists of two seperable sections positioned one upo e otherth n e fueTh . l element f eaco s h sectio e arrangear n hermetia n i d c closed AlHg -container e reactoTh . r tank enclose e core d partth sth an e f o s reflector. The pressure inside the reactor tank is 13 kPa smaller than the surrounding pressure.

The jpntral h.jriointal 3xperirent.il channel gop-> Ihr >Jgh the upper core section, ^f the reactor is cut of operation ïhe 1 iwer core section is ^i vvered by ^0 mm.

.be reactor is controlled by three absoroing cadmium-plates which are ved vertically ^ncid e reflectoth e r outside reactoth f o er tanke Th . c^/roUTOunde5 j. e a reflecto y b d f purc r e graphi e axia Th d radia t. an l l

78 reflector thickness is 200 and 320 mm, respectively. The critical mass ?35 of the AKH is about 790 g JJU.

3- Utilization of the research reactors

. Genera31 - l tasks

During the first years the Rossendorfer Research Reactor RFH in general e trainin th e reactos user th wa fo f dgo e nuclear th staf r fo rf power plant Rheinsberg which was put into operation in 1966. All of the operators had to work at the RFR for about a year and a part of the personnel having a managing position at the NPP was taken over from the CINR /3/-

Besides e e firsreacto th th a stron n te i s s ,begua ryear us wa go t t ni s neutron source for research work in the field of nuclear physics as well as to carry out reactor physical measurements. Neutron diffraction beam studies starte n 195i d 8 wit a neutroh n power diffractometere th o t p U . present a triple axis neutron spectrometer, two double cristal diffracto- meter for investigation of perfect cristals and for small-angle neutron scattering and two diffractometers for texture analysis of materials and geological specimens have been installed diffractometerl Al . e th d an s spectrometer operate automatically, som f theo e m controlle y microcomb d - puters .

The first radioactive isotopes already have been produced in the RFR in 1958. At present the annual volume of isotope production may be characterized by the number of about 40 000 packages representing an value of several million f Dollarso s . Main product e tritiuar s d carbon-1an m 4 labelled organic compound d nuc1^ar-pharmacrtban s e mosTh .t import-mt pharmaca e basear s n o d tcchnctium. Fissiun molyhderuu e generatioth s user i m fo d f technetiuino n - compound1-. ["> n T T. few years the production of radioactive isotopes together wite voluminouth h s productio f neutroo n n doped silico s becomha n e th e main task of 4ne reactor.

Becaus ^ poweth e r electronic industrie needs homogenous neutron doped silicon special devices for moving the material during the irradiation e realtoth n i r e developedhp.b o dt e non-uniformitTh . e axiath f lyo flux distribution was reduced by the installation of a graded absorber of nickel iil^o> aroun~ e f miximu1 o n1 d m flux e e aDoorbeshapth Th . f o es tneorewa ry l l ca ti calculated. It equalizes the flux over a length of 280 mm within 1,5 %•

79 Sinc e firsth e t e reactoyearth f s operatiow beeo sha no r no t use p s u a nd neutron source for neutron activation analysis. About 15 peoples are dealing with this tas n cooperatioi k n with more tha 0 partner3 n s from industrd an y research institutes /9/• The RPR operates for about 100 hours per week.

Until 1972 the zero power reactor RRR in the CINR mainly was used for investigations of space dependend neutron kinetic processes. In 1972 a fast reactor lattice containing high enriched fuel was inserted into the ringzone of the thermal reactor /5/. In the centre of this fast lattice a neutron spectrum corresponding e neutroth o t n spectru a fas f to m breeder reactoe obtainedb y ma r . Using this arrangement cross section f materialo s s beein f interreso g r fasfo tt breeders can be found. Numerous neutron scattering and neutron absorption cross section f structuro s e materia d fissioan l n products were measured. Simultaneousl e experimentth y s wite fasth ht lattice serve r verificatiofo d n of computer code r energ fo sd spacan y e dependend neutron flux calculations.

e researcTh e hzer th woro t a powek r reactor RAKE dealt with researchinf o g neutron kinetic processes by means of a pile oscillator and with measuring e reactivitth f o y weigh f fueo t l assemblie e Rossendorth f o s f Research Reactor RFR. Beside it, the reactor was used for calibration of detectors and for testing of new measuring methods.

e zerTh o power reactor n Dresdei R d ZLFAK s an n Zittai R u mainly servr fo e training purposes. Specia b coursela l r studentfo s d engineeran s s deal with reactor physics and operating problems of reactors and nuclear power plants.

e followinTh n experimentte g s have been made out.

- radiation protection - detectors for ionizing radiation - reactor simulato (controI r l rod) - reactor simulato (xenoI I r n poisoning) - temperature distribution in a fuel element - operation of the ZLFR - radiation shielding - contro wortd ro l h function - environmental monitoring - neutron flux distribution in the ZLFR core.

80 The research work of the ZLFR is concentrated on noise analysis measurements. wilR a neutrousee AK b l s e a d Th n sourc r developmentfo e , calibrationd an , test f radiatioo s n detectors.

3. 2. Development of Nuclear Power Plant Control Systems

Since about 1975 the Rossendorf Research Reactor RFR has been used for the development of control systems which will be employed in NPP's in GDR.

To get experiences in designing and developing of computerized control systems, a Hierarchical Informational System (HIS r surveillanc)fo d controe an e th f o l s beeRPha R n developed. Main task f automationo s e solveb o y thit ,b d s system are /10/:

- process monitoring, which includes acquisition, preprocessing, monitoring, d logginan f dato g a - technical diagnosis, that means elaboratin methodf o g r on—linfo s e disturbance analysi d noissan e analysis - surveillanc powef o e r density distributio meany b n f self-powereso d neutron detectors

- process control e. g. in the sense of direct digital control and reactor starb-up and shut-down procedures - use of a spec-rial industrial robot for loading operation with material to be irradiated in the reactor.

The system HIS has been realized by using of computer technique produced in the GDR. Fig. 7 show e generath s l structur systeme th f o e.

Becaus e computerizeth e d informational syste S especiallHI m s beeha yn developed to meee backfittinth t g requirement s some RFRha th et i f ,featureso s , which are different from those of systems installed at NPP's. Some of these destinations are :

- much lower number of process inputs and outputs

- shorter distance between poecess and Computersystem

- solving different research problems.

But nevertheless the system HIS enables the reactor staff to get experiences with such a system and it also may be considered as a pilot system for developing and testin f methodo g d programman s s later use NPP'sn i d .

81 The tasks discussed previously in general have autonomous characteristics, but they were very closely linked by the procebs. Thus a. decentralized hierarchical system, shown in Fig. 7 seems to be the best solution to meet all the require- ments mentioned above.

MAIN COMPUTLR COMPUTER PROCESS ROBOTRON CGMMUNIKATION COmUNICATIUN K 1620/K 1630

fc F SERIA(I S BU L LS) 11 BASIC UNITS l URSADAT 5OOO URSADAT 5000 URSADAT 5OOO (ROBOTRO K 1520N ) (ROBOTRON K 1520) (ROQOTRON K 1520)

TECHNOLOGICAL PROCESS (RFR)

Fla.7 HIERARCHICAL INFORMATIONAL SYSTLh (HIb) ChNERAL STRUCTURE

The system consists of various basic units which are situated nearby the technolo- gical process and linked with the main computer via a serial bus, the so-called IFLS interface.

The basic units (ursadat 5000) are connected to the technological process. Each unit consists of a microcomputer Robotron K 1520 and several process I/O modules.

It is primary used for data acquisition and preprocessing procedures, but further- more other tasks can be performed too. e maiTh n computer (Robotro K 1630n ) generall o functionstw s ha y :

— operating iiMnagarnent problem e systeth n i sn includin e man—machine—corjruth g — nication

- solvin f real-timo g e tasks with higher demand n processini s g timd memoran e y e requirementTh e linth ko t softwars e realizin e IFIth gS mainly were deduced as well fro'n experiences obtained by earlier computer applications : n NPP'a as f-"om actual tasks at the RFR As the result of distributing tbe control problems on both "otnputer levels, the majority of transmission roquet,! fc corner

82 from "the upper level r thaFo . t reaso e maith n n computer permanently operates as a master station, whereas the basic units only have the slave position e busth .n o

e IFirTh > interfac e realizeb y n electrima ea s wel a ds a l c cabla fibe r o er . optine : 1 c

Great importanc s attachewa e n particulai d e developmenth o t r f modero t n methods of man—machine-communication because these problem f importano e ar s t interest fo NPPa r .

. Summar4 y

e existencTh f researco e h reactor s essentiai s r eacfo lh country whic s realii h - zing a nuclear energy programm. Research reactors are of great importance for the education and for continued professional training of specialists. Besides, reactorphysical problems can be investigated and codes can be tested on such reactors n dependencI . n theio e r construction research reactore s th serv r fo e development of NPP-components too.

In this connection in the GDR the research reactors are mainly used for the developmen f diagnosio t d automatioan s na microcompute technologyf o e us e Th . r based automation system at the RFR for instance allows the test of hard-ware and soft-ware components of such systems. Above all, the RFR is used as an efficient source for the production of radioactive isotopes and of homogeneous neutron doped silicon.

References

/1/ K. Rambusch Kernenergie 28 (198b), b

/2/ R. Adam u.a. Die Ieistungserhohun s Rossenderfede g r Forschungsreak^ors 2 WWR- n Svo W M 0 1 f au Kerrerergi (1969)£ 0 _1 e1 . ,H

. Hieron^muW / /3 s 2b Jahre Rossendorfer Forschungsreaktor Huckblick, gegenwärtiger Star.d und künftige Plane Kernenergie 25 (1982) H. 12

83 . KampfT . LiewerP , s Der Rossendorfer Ringzonenreaktor (RRR) - ein Instrument für reaktorphysika- lische Untersuchungen Kernenergie 6 (1963) H. 7

/5/ K. Fahrmann u.a. Der Einsatz des Rossendorfer Ringzonenreaktors für Untersuchungen zur Physik schneller Reaktoren Kernenergie 25 (1982), H. 12

/6/ G. Huttel u.a. Die Rossendorfer Anordnung kritischr fü e Experimente (RAK) 2 E Zentralinstitu r Kernforschunfü t g Rossendorf ZfK - 232 (1972)

/?/ G. Ackermann u.a. Der Lehr- und Forschungsreaktor der Ingenieurhochschule Zittau Kernenergi (19792 2 e 9 . )H

Ada. E m u.a/ /8 . Der Ausbildungs- und Forschungsreaktor der Technischen Universität Dresden Kernenergi (19792 2 e 9 . )H

/ /9 ZfK-Repor (19844 52 t ) Proceedings der 3- Tagung Nukleare Analyseverfahren 11-15 April 1983, Dresden/GDR

/10/ J Klebau, S. Seidler Backfitting in Rossendorf Research Reactor Contro d Instrumentatioan l n System IAEA NPPCI Specialist's meetin n Backfittino g r Nucleafo g r Power Plant Control and Instrumentation 25 - 27 April 1984, Vienna, Austria

84 UTILIZATIO FRG-E D TH AN 1 F NO FRG-2 RESEARCH REACTORS

. KRULW L GKSS-Forschungszentrum Geesthacht GmbH, Geesthacht-Tesperhude, Federal Republic of Germany

Abstract

Following a listing of the various research reactors in the FRG, the GKSS-Geesthacht a ) MW d FRG- activitieam 5 (1 2W H e FRG- e 5 th ( ar t1f o s listed. These include energy research, reactor safety research, neutron scattering, activation analysis, neutron radiography, radioisotope production, gamma irradiation, silicon transmutation doping, educatio d economicsan n .

1. German research reactors

Triga Mainz 100 KW Heidelberg 250 KW Hannover 250 KW Neuherberg 1000 KW shutdown 82 " Frankfurt 100 W 0K never operating

FR-2 KarlsruhW K 4 4 e shutdow0 8 n 5 8 - " - - SNEA" - fasK t zer . op

FRM Munich 4 MW FMRB2) BraunschweiW M 1 g W M 0 1 » BER-2• W M 5 3) Berlin FRJ- W M 10 1 Julieshutdown 5 8 n FRJ-2 - " - 23 MW FRG-1*) GeesthachW M 5 t FRG-2*) - " - 15 MW

Upgrading, backfitting *)= 1978/79 2)= 1984/85/86 3)= 1986/87

85 2. FRG-1 and FRG-2 research reactors GKSS - research centre Geesthacht GmbH

90 % BMFT / 10 % northern states - funding 0 employee70 s f activityo % nuclea 0 (4 ) r - reactor safety (materials) - (reactor development?)

- PSS ./.

non nuclear (60 % of activity]

- submarine welding

- environmental protection

- clima research

- materials research!

- membrane development

GKS - researcS h centre Geesthacht

FRG-1 FRG-2

Power 5 MW 15 MM Criticality 23.10.1958 16.03.1963 MWd/a (ca!) 800 3.200 Utilization isotope production isotope production beam tubes materials testing (CMS, July 1987) - pressure vessel steel NAA - defect fuel pin silicon doping - Zirea y creel1o p

Number fuel elements 39 (18*) 41

Number control rods 4 ( 5*

Number special fuel elements 2 ( 3*

coolant flow 760 1.650 *) future

86 3. Energy research and energy technology e Federaith n l Republi f Germano c y

- Fast breeder reactors High temperature reactors Uranium enrichment Reprocessing and waste disposal Safety of nuclear power reactors - Nuclear fusion, plasma physics Fusion technology Non nuclear energy system

o researcN ! d developmenan h t progra r furthefo m r developmen f nucleao t r power plants

Safet f nucleao y r power reactors evaluatio d determinatioan n f safeto n y factor r nucleafo s r power plants and their systems and components further development of safety technology contro f nucleao l r material flow high temperature reactor safety research development of health physics measurement techniques

87 4. GKSS contribution to reactor safety research (FRG-2)

1. Test and qualification of high density fuel for research reactors

. Fissio2 n product release experiment

. Embrittlemen3 f pressuro t e vessel steel (component safety program)

Literature:

. KrullW ) 1 : Reduced enrichment activitie t GKSSa s , International meeting, Petten Oct. 14-16, 1985

. 2AhlfJ ) : Irradiation experiments relate o reactodt r safetn i y particular pressure vessel steels Nucl .Desig5 d Eng24 an 1 (1984- . 8 n 1 23 )

. 3AhlfJ ) . BellmannD , , F.J. Schmitt Spalthoff. W , : Investigation on the dependence of RPV steel embrittlement on irradiation tem- peratur d neutroan e n exposure, GKSS 82/E/43 (1982)

. Reymann4A ) . J Ahlf, . BellmannD , , K.-H. Blom, H.L. The: First operation experiences with an irradiation device for the test of defect fuel pins under PWR conditions, GKSS 83/E/45 (1983)

Qualification of fuel elements

U-235 burnup 26.11.1985

1) UA1X 45 % 1,41 g U/cc 280 g U-235 59 % - 64 %

2) U308 20 % 3,1 g U/cc 270 g U-235 46 % - 60 %

3) U3Si2 20 % 3,7 g U/cc 323 g U-235 36 % - 41 %

1) backup variant 2) fabricational limi backu+ t p 3) FRG conversion

88 Investigation of fabn'cati'onal limits

GKSS part: increased fine grain reason: minor or important impact on swelling? test 5 fue:l plates 03813 19,7 % 2 4,7 g U/c5 c 3 platmm e 0 20 x 0 6 1,2x 7 3 meamm t 0 18 x 0 5 0,5 x 1 3 fuel plates 40,fin% porosit2e% 2 grain8, y , 2 fuel plates 17,fin% porosit3e% 5 grain6, y ,

March 1985 - Summer 1986 ca. 60 % burnup

burnu2% 4 p 15.10.1985 on line fission product release measurements no priority

Objective of defective fuel irradiation experiment e tesTh t objectiv o investigatt s i e e fissioth e n product (fp) release and operational behaviour of defective fuel rods of modern PWR design:

- fission products release of defective fuel rods under various power conditions

formatio e defecd growtth an n f o th under continued fued opero l- ration

- changes of the fuel microstructure and cladding hydriding and oxidation due to the continued power operation of the defective fuel rod.

Main design parameters: ca 155 bar, 310 °C, 30 cm fuel rod with ca 250 W/cm

89 GKSS FORSCHUNGSZENTRUM GEESTHACHT GMBH

Oberer S.kundäfbehälUr Upp«r Secondary V«»««l

AM*gi«tchsbehalter Compan*atjna V**Mi Leerelement Holtow Et*m*nt Füllstandssonde |-«v«l Qauga Unterer Sekundärbehalter Heizung Low«r für Druckhaltung Secondary VIM«) HMtor for Pf*»*urUallon Druckrohr Pr«Mur« Tub« Wärmesperre H«at Barrio Bohrung für Monitordrähte Hol* lor Monitor Wir«»

Elektrische Heizung Ertctrtc») H«*t«r Pumpenmotor Pump Motor Brannstab Fu«4Rod

Gasspalt G*» Gap

Leitrohr Guld« Tub« Pumpe Pump Kühlwasserspalt Cooling Wat«r Chann«!

Öffnung für Brennstabwechsel Kabeldurchführung Optning Cabl« P*n«trat)on for FueExchangd Ro l e Kapsei *^^' für die Bestrahlung von Brennstäben unter DWR-Bedingungen Irradiation Rig for Testing Fuel Rods under PWR-Conditions

90 Gas Supply System Z l Flow Sheet (simplified)

Off-Gas Monitoring System

Storage Tank

Water Supply System

I^A) Activiy © Mass Flow 0 Pump Current CD Level y) Conductivity Waste Water System Pressure Difference Secondary Tube w Pressure Auxiliary Heater @ pH Value © Temperate ur Neutron Flux Degassing Tank Waste Water Delay Tanks 92 COOE FLUEMCE FUJI DPA IRRADIATION T(iU) T(68J) USE T(0.9nn) USLEI T(50s) i neu» (E > 1 neu) CASTP) TEHPERATURE <£*23/fw«2i (E*i6/n««2/si (*> Co ce» ce» (j) co

O AH UMIRRAOIATED 6.5 £3.5 85.8 15.2 1.63 A AH 2. "U 230.2 56.0 102.5 TÎ.4 63.0 1.^7 56.1 + AC •».T« i.12 15.1 288.2 128.2 209.8 72.0 133.5 1.23 116.1

AT< 68JI AUSC AT(0.9nm AUSLEX AT(50«) ( Kl < Kl (J) ( K» (mi ( KI 8 50 ± 4 t < >3 3 8 t 2 5 0.16*.OS 51 ± 3 8 H 6 ± 2 12 166 ± 6 1^ l 3 5 0.4.01.06 111 ± i.

ÜJ {- <_>

68 J

41 J

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-200.00 •130.00 •100.00 -30.00 0.00 50.00 100.00 130.00 200.00 250.00 300.00 TEST TEHPERATURE (°C> Change of impact properties of steel KS01 "•O by irradiation [TDM]

6O SoM -2000 (MJ)

Soil H Material « Investitionen (TDM) 50- -1500

40-

30- -1000

20-

500

10- in. 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 Zelt

Pcr*oo*l- und S*ctnitt«l«in»*tx für druckbch£lceritahl-Profr —————— _|_» . l»7t" i»T«t«WjmiilWBi«Wj«»«4«»;iW ;«•,•W » T W»1O «______r ' i(T : . . 11 ————— _ a^ L ————1 i ( _ l 1 r J.i l————— g' , i — i^-i CM OO 1 79 ' * ' — 1 ' — —""" ^ * 1 — 7 — — — * "~ 130 1 T> '»•41«» •0 2 2JO 1 •»•»•* a , , . __ f__ 130 2 2jO ' •O 4 7.» 130 3 7» ' «V»M l ——— ! ' - < •O 9 2JO n«n •*! ; 12O 4 2J0 ' '— ! — i 00 9 Q» | KIO1 OW 0 130 7 0,9 ' «»01 wtl c B0~e 79 j ' l «A 120 « 2JCX ' »0«M *. 00 7 2X> l »a»K> * — j ' 120 9 79 i t ' j ; i 00 K>2.0 , irwm •«•lau «*e»o» «VMM OO 11 79 ['—•»I • !«•«• IOM»U« I ' ] 1 1 X» 1 10 T-ij-i-l 3 —— ! ;—

H» 2 20 KS01OW • »0 1M CJ __

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no 4 79 »01 a« «»Ol »c 'i! K» 9 0.9 moid* i 4 100 e 2.0 uni sa WO 7 79 —r ~"— * — ^ ^ i * r 1 t T _..., ««r>l 1 •In! J • M 3"M

•hnl 4 70 ' r t 1 ! < 1 •In! Jjoi i . ! cz^^^r^rt^ —————— L-i , , , | O 1J2.9 K OC «ST CD 1 — — l [f 90 7 79 HSST Oï 00 1 79 4 ^" -« 00 2 20 >r>ra M »M : 00 4 79 *•' t - - - _ _;"_ ' Ji 00 9 2jO r~; v 1 OO 12 0.9 | OO 13 2P l;-" | 00 14 2O

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RDB- Stahl -Bestrahlungen IMS) 5. Neutron scattering experiments at FRG-1

Research areas

e behaviouTh . 1 f materialo r s under neutron Irradiation

- the influence of alloying elements - analysi f radiatioo s n induced defect structure - correlatio f defeco n t structur d mechanicaan e l properties

2. The behaviour of amorphous alloys under neutron irradiation

- radiation induced relaxation processes - physical property changes produced by irradiation - structural defect analysis

3. The kinetics of diffusion-controlled phase transformations

- Experiments SANS, Analytical TEM, fiel n microscopio d y - Theory Computer simulations - Effects on mechanical properties

. 4 Underwater welding

- Analysis of microstructures (TEM)

= transmissio M TE n electronic microscopy

96 Experiments at the FRG-1

1. Small angle neutron scattering (SANS) with colpolarized dan d neutrons

- analysi f defeco s t microstructure n crystallini s d ean amorphous materials - characterizatio f diffusiono - ncontrolle d phase trans- formation n alloyi s s - structural analysi f polymero s biomoleculed an s s

. 2 Elastic diffuse neutron scattering

- short range orde shord an r t range clusterin n alloygi s

3. Incoherent elastic neutron scattering

- detectio f hydrogeo n weldn i n s

4. Neutron texture analysis

- metal alloyd an s s (e.g. steels) - geological samples - mineralogical samples

. 5 Neutron radiography

- non destructive testing of materials - application to medical/biological problems

Experiment e FRG-th ) t a 1(2 s

. 6 Neutron capture prompt T-ray activation analysis

- detection of Cd in sediments

. 7 Neutron activation analysis (NAA)

- detectio f traco n e elements (e.g. in environmental research)

8. Isotope production

- researc d industran h y

. 9 Silicon transmutation doping

10. y-i rradiation

- research and industry

97 Texture analysis

Def.: Textur e crystallographith s i e c orientation distribu- tion of the crystallites of one phase

Interest e propertieTh : a polycrystallin f o s e sample depend first- ly on the properties of the single crystal and secondly on the orientation distribution of the crystals of each phase

- to prevent undesired textures o manufacturt - e with well known texture - to develop new materials with desired properties - to study the history of a sample (recrystal1ization, deformation) o analyzt - a multicomponene t system (the degre f preo e - ferred orientation mus e knownb t )

Polarized neutron SANS

Method: JJynamic rmclear £olarization Polarizatio f magnetio n c moment f H-nucleo s i OH = scattering length + n t = 0,375 + 1,45 p » n - p polarization

Research: Interaction f proteino s d nuclean s i acids esp. determination the role of ribosomes within the synthesis of proteins.

98 More cold ) neutronA 5 . 2 X ( s

In July 1987 a cold neutron source (25 K, 15 bar) will go into operation. In addition a Be-reflector around the beam tubes will be installed and other measures will be taken

increase numbe f colo r d neutrons 8 5 facto0 5 r 18 0 facto0 r13

. KrullW ) 1 see:: Design consideration r colfo sd neutron sources, IAEA-seminar, Tripolis, Sept. 1984

2) W. Krull, K. Hansen, J. Stein: The cold neutron source for the FRG-1 research reactor at the GKSS research centre

99 6. Neutron activation analysis

. 1 Water pollution (Elbe, Weser, North Sea) - suspended matter, sediments

2. Air pollution - filtrates

3. Biological samples - fish, shell ...

4. Medical samples - medicament n organici s s

5. Geological samples - quartz - national deep drilling program (>1) 0km

6. Diverse

prompt y-ray NAA (Cd e.g.)

. SchnierC ) 1 see Marchig. :V , . GundlachG , e chemicaTh : l compositio a wate se d por an rf o ene wateth n i r manganese modul e centrae th are f o al pacific, GKSS 81/E/64

2) C. Schnier, R. Niedergesäß, L. Karbe: Compilation and mappin f traco g e element musseln i s s from German coastal waters, GKSS 82/E/27

3) C. Schnier, H.-U. Fanger: Development and application of an iridium tracer for tracking tailings in the Centra d SeaRe l , GKSS 83/E/67

100 7. Neutron radiography

n pooi l . 1 (FRG-2) - fuel rodd fuean sl elements pellets, burnable poisons, ytterbium ^-getters defects - finger absorbers - irradiation devices

2. beam tube (FRG-1) - electronic tubes - medical samples (Tumor, ... - biological samples (shells, tree-slices, - turbine blades - burnable poisons - principal investigations - tomography - standardization - technique

3. hot cells or storage pools

Sb-Be ) sourcn , (y e

- fuel rods

- absorbers

Literature: 1) Deutsches Patent P 3031107.0-33 (1982) 2) L. Greim, W. Spalthoff: Inspection of reactor fuel- and absorber- elements by means of neutron radiography with a small size anti- mony-beryllium neutron source, GKSS 83/E/17 . DiemkeE ) 3 . GreimL , : Fast neutron imagin y cellulosb g e nitrate films, GKSS 83/E/18 . DiemkeE ) 4 . GreimL , : Biomédical application f faso s t neutron radiography, GKSS 84/E/43

101 8. Isotope production (n-irradiation)

, LaF3Ho , La CeÛ21 ., ,Hf e.g , EUC>2..Cu . . universities

- sediment r C , Se s mobilit. 2 y

, wateFe , r Si , Hg , Ag , Sn , In , Co , Au . 3 industry

4. J in biological samples - research

5. Diverse biological and environmental sampler fo s industry and research (e.g. sediments, minerals, fish, blood serum, grass, pine needle, pork feed w liveco , r ...)

y-irradiation

Diodes Electronic components Precious stones (gems) e.g. diamonds, topas, beryll, turmaline Silicon oil Araldit, rubber Glass-fiber reinforced plastics Photo conductors

Silicon transmutation doping

Refer.: paper presented at the IAEA - consultants meeting Institut f atomio e c energy, Warscha Swier- u k 20. - 22. November 1985

102 . Educatio9 n

1. No power reactor operators (trained by utilities, own simulator)

2. Students yearr pe x ) 2 (

. 3 Research reactors e.g. MPR-30 (15 operators 1985, 1986)

4. IAEA-inspector training two weeks in 1985 and 1986

10. Economics

See paper

W. Krull: Remarks on the influence of enrichment reduction on fuel cycle cost

RERTR-meeting, ANL, 15.-18. October 1984 ANL/RERTR/TM-6

103 PAST AND PRESENT USES OF CEA GRENOBLE RESEARCH REACTORS

J GARCIN Service des piles, CEA, Centre d'études nucléaires de Grenoble, Grenoble, France

Abstract Th Frence e th use f ho s Atomic Energy Commission (CEA) Grenoble research reactors are presented. The main features of the three swimming pool, open core, MTR type reactors, SILOE (35 MW>, MELUSIN (8 MW) and SILOETTE (100 kW) are described. Their uses are described in historical order along with the important relevant reactor upgrading that permitted scientific and technological advance. Finally, the beneficial advantages of those research reactors common type are recalled, as demonstrated by their achievements.

1. PURPOS E REVIETH F EO W

This paper is to contribute to a current IAEA case demonstration of how the nuclear research reactors have been so far helpful tools of the overall development of the scientific and technological infrastructure of national communities It deals with the uses e Frencoth f h Atomic Energy Commission (CEA) Grenoble research reactors s thosa , e uses were briefly stated m a preliminary oral presentation at the Budapest December 1985 meeting In no way, the materials presented here are new as they were continuously reported to various audiences In the past and until recently (see the references) As such t i shoul, a reorientee rea b ds a d d compilation toward e Budapesth s t meeting objective readeth d r an e wil e repeatedlb l y directe o thost d e former Grenoble Reactor Department publications The style will be more qualitative than quantitative

First, a quick look at the main features of those reactors will be taken Then, their uses will be reviewed In historical order with the important relevant reactor upgrading that permitted forward technological or scientific advance Finally, the beneficial advantage f thoso s e research reactors common type wile recalledb l s a , demonstrated by their achievements

2 QUICK LOOK AT THE FACILITIES : OPERATING FEATURES

e GrenoblTh e Research Reactors (GR r Rshortfo ) were never dedicatea o t d single objectiv t werbu e e wante e permanentlb o t d y multipurpose reactors n ordeI , o t r e eveadapth r o t tchangin g natur f researceo developmend an h t demand while complying to the more and more stringent safety regulations

, MELUSINER GR Al3 l , SILO d SILOETTEan E e swimming-pooar , l open core MTR type r reactorthefa yo S havs e useI fues productioa UA dl n fuel with optimized design They have benefited mutually from equipment standardizatio n optimuA n m selective utilization coul bettee db r obtained throug commoha n managerial structurt i s ea could maintai a varien d spectru f irradiatiomo n product d servicean s s

The main present operating features of the GRR are listed in Table 1

105 TABL 1 ETypica l present characteristic f Grenoblo s A researcCE e h reactors (partly trom [21)

SI1JOE MELUSINE SIDOETTE Reactor type swimming-poo1 id. id. MTR First critical 1963 mid-1958 1964

Constitutive features: Nominal power rating 35 MW 8 MW 1OO kW Fuel type UA1% 93 , id. id. enriched Max fuel plate heat flux. We: m2 160 4O - 0 Primary coolant flow, 3-1 m h : 2500 7OO N.A Reflector type H O, Be H O, D O H O, Be z 2. Z 2

Performances : flux irradiatior Ma fo x n testin productionr go , corn i e( ) nc3 m 14 thermal : 4x10 e.oxio N.A. 14 3 1 fast ( E*O . IMeV ) : 4.5x10 5.5X1O N.A. Max beamn flu n xt o sa monochroraator location: — 2 —1 thermals m :nc 5x10° 8x10 N.A. associate therma faso lt t flux ratio: 22 150 N.A. best thermal to fast ratio 700 N.A. Typical reactor cycle. a few hrs. Full Power Days 21 24 each day Average yearly operating

duration HourP F , s 5500 6OOO Availability factor: 98.7% 99.3% 100%

Fro e startm th threee e oldes ,th th f MELUSIN. o ,t ) 2 d an E 1 (photo g fi n o s first critica mld-1958n I l assignes wa , d primaril neutroo yt n beam researc t practicallhbu y all the other activities listed herebelow were later on also developed on that reactor, except educational uses.

e SILOTh E reacto orderes wa ) r 3 d (phot g mainlfi n I oo suppor t y e nucleath t r power fuel development programmes designes wa t i d d an originall, lOMWta r yfo h power, IxlO1* n.cm^s"1 thermal flux levels Mainly because of these nuclear power development programmes, was the reactor power raised successively to 15, then 30 till e sooneth d ran thaW finallM t upratm5 3 y g cam f thao e bette th ee te ful reactoth us rl r went

106 FIG . Melusin1 . e reactor.

107 . FIGMelusin2 . e core.

108 FIG. Silo3 . é reactor.

109 4 Siloett G FI e core

110 At laste SILOETTth , E reactos usewa d ) r 4 mainl (photg ti yn I ofro m 1964 till 1978 as the core neutronlc mock-up of the various core patterns chosen tor SILOE and MELUSINE applications equippes wa t I . d also wite radiahon bean l m whic uses r hwa d1o some tim r developmenfo e f neutroo t n radiography applications. This core mock-up considerablw activitno s ha y y recesse a larg s a ed spectru f mwell-knowo n so-called production cores has been capitalized by the Reactor Department. SILOETTE is now almost entirely devoted to educational and training uses together with department- developed power reactor simulators.

3. ILLUSTRATION OF PAST AND PRESENT REACTOR USES

e Almosmateriath l al t l developed herebelo s alreadwwa y fully covere a 198 m d 1 trench journal issu ] [1 eUpdatin o 198gt 5 will thu thie b ss paper's main ambitions i t I . instructiv e historica useth R n o i reviet sGR e e l wth orde whicm r h thea y s a cam t ou e cas e nucleaeth indicatow ho r f knowledgo r s energit d yan e applications developem d France m the past thirty years or so. It is never to be forgotten that GRR uses developed so well becaus e préexistencth f o e Grenoblm e a mos f o et qualifie d diversifiean d d scientific community, especially in the field of solid state physics, electrostatics, very low temperature technology, in the 2 decades prior to MELUSINE's erection, and because of e establishmenth a loca f o tl nuclear engineering school (graduate level n 1953i ) .

1 Neutro 3 n beam uses (see tabl) 2 e

usesR GR ,A e scam th firs f o et basic research wit n beamh e incentiveTh s o t s orde a researcr h reactoe latth e m fiftier f e samtoday'o s th wers t a e no se world with widespread nuclear applications.lt is only anecdotic to say that m 1957 the Grenoble demand for a research reactor (MELUSINE) was for a thermal neutron beam; worldwide order of MTR type research reactors at that time responded to a much wider spectrum than MELUSINE's uses

Designed wittangentia2 3 radiahd an l l beam , MELUSIN ) s1 (photg fi n Ei o bego a wealtt f physico h s findings with developmen a numbe f o t f differeno r t neutron diffractometer d spectrometeran s poweW M 1 r A ratina compacs f o g t enricheI UA d

core was sufficient for that research order of 10 n cm~s~ at the monochromator

2 1

location Power upratin f thio g s reactor followed (tabl ) 2 mostle 7 y becaus f beao e m research demand for higher thermal fluxes, permitting faster experiments runs, investigation of smaller neutron cross section events. A sample of the basic research achieved Is given in Table 3 In the recent years, experiments run at MELUSINE benefite reflectoO dD fro a e settin f mth o r larga p tan gu s a ke therma2 l source th r efo

tangentia2 l beams principally. That tank has built-in housings for cold and hot neutron e lateth source r; howeve4] [ s t beer ye havt n no orderee d

SILOE construction order came out only 2 years after first critlcallty of MELUSINE because the later could not keep up with the fast growing demand for In-pool neutron irradiations A berylliu. m reflecto s beeha r n ther n constanI e e froe us th mt reactor origin [4 bis] MELUSINE has always tried to catch up with SILOE n beam thermal

flux levels by improvement of the beam flux quality (better neutron thermallzation by D2O than by Be) and promotion of the tangential beams.

Despite the everly trend of n beam research use of colder and colder neutrons and the advent ot the nearby HFR in 1971 (cold neutron sources, wave guides), MELUSIN d SILOEan E have still kep shara t f thaeo cannoR t researcHF e t th fulfil l s a hal l the demand. Thus, what was stated In 1977 [4] Is still valid today " . . In the present stat f arto e , research reactors hav o competitorn e e thermath d subtherman i san l l neutron energy ranges, whereas accelerators do better In the fast one. . . Extracted n a non-prohlbitlvel f beamo e ar s y costly operationhighe% 50 t r no tha, n other relevant neutron sources" . . .

111 labi é2 GRR's upratmgs

MELUSINE SILOE SILOETTE

Original design power d datan e 1MW, 1958 10MW, 1961 lOOkW, 1961 Actual 1st rated power and date 1MW, 1959 15MW, 1963 lOOkW. 1964 Further upratmgs, date, and associate major demand: 2MW, 1961, n beam reaearch 4MW, 1965, n beam research, radioiso topes 30MW, 1967, nuclear power programmes 8MW, 197O, n beams, radioi . structural materials test 35MW, 1971, nuclear power programmes

Table 3 Examples of physics and chemistry research done with SILO d MELUSINan E E reactor n beams s

1 Dlffractometry (n Bragg scattering):

Powder study -cristallography -stud f magnetio y c structures - behavior under T,H,p conditions ( multidetectors, time of flight techniques)

Monocrystalline study -magnetic density mapping - magnetic phase diagram at low T involves high H, cryogenics techniques

n spectrometr2 y (inelastic scattering)

-study of dynamical properties motion of atoms (phonons) and motio f magnetio n c moments (magnons) - cold neutron scatterin t smala g l angles' solid state physics and metallurgy materials science

3. Others

- mass spectrometry (tim f flighto e f actimdeo ) s fission products ' yield, energy spectrum, fission was induced by beam neutrons Into mlcrosamples

112 Tabl 4 e Main racHosotopes produce y SILO b dd MELUSINan E E

Medical use Condi- Typical Main radioiao topes Production tioning Decay specific end (generally Reaction in period activity use high activity reactor Ci/g («) sealed sources) when unspecified

Co r y 7 2 . 5 1:100 (n) ,y Co pellets radio y several therapy grains ( "Co-bomb" )

66 hr 0,2 several brain grains scinti- MO ( fission ) Z3S graphy : U 6 hr diagnosis 93 % enri- of ched tumors

Zr 74 d 2O:2OO n,y Ir threads Local several implant grams therapy ( cunether- apy)

8,02 d byproducts Thyroid of above U fission s gland. . ,. 8 "MO production Luna di g Xe 5.27d gnosis, . Industry use (either sealed or unaealed products)

tiny Co NDT Co pads - food conservation (bactéries killing) see above; source-y s ( y graphy) -level transducers Ir Ir threads

Hg, Au, Y, ordef ro nonsealed Ba, Na, Te, mg inside sources , Re, Ir, . . . pneumatic tracers rabbits

(") 1 Ci = 3 7x10J Becquerel

13 3 2 Radiosotope production [5]

Man-made radioactivit s multiplha y e known applications Productio f radio n o islopes has developed m GRR from the very start of MELUSINE as the thermal flux, yet as

low as 1 x 10 n crn^s", was sufficient for most of those wanted Table 4 quotes

s 1

those now producei d in the GRR at industrial scale

Medical end use radioisotopes tend to require hisher specific activities and thereb a finay l conditioning before marketin a license y b g d laboratory Reac f theso h e activities can be obtained either by use of higher flux in-core locations or by augmented irradiated masses Instead, e radioisotopeindustrus d en y e generallar s y needew lo t a d activity level and can be produced with an m-reflector neutron activation analysis reactor equipment, they are marketed either sealed or unsealed according to their activity

MELUSINE and SILOE production is managed by ORIS, the french national body in charge of the conditioning The type of the radioisotopes produced m the GRR follows the national trend either the end user is close enough to the reactors and its needed short-lived radioisotope e obtainear s n thesi d e reactor r theo se produce ar y n i d accelerators (cyclotrons. Van de Graff) installed near-by this end user

3 Neutro 3 n Activation Analysis(NA r shortfo A )

This techniqu s weli e l documente n literaturi d e

s bee ha eveR nA ThrGR pratice NA esince th em d MELUSINE firstt a powe n ru r 1 MW[6] Counting task soon required a particular laboratory to be built, the Medium Activity Laboratory ( LMA) Historically speaking, prior to and into the sixties decade, gamma countin d unfoldinan g s donwa ge wit a scmtlllatoh d quantitativan r e analysis required nuclear chemistry techniques Since the advent of multichannel analysers (setup in 1961 as of Grenoble) and Li-doped Ge diodes (1967), post-irradiation chemical separation of sought radioisotopes is no longer needed Industrial scale NAA need o hign s h thermal d thus flubeean ha xs n don n MELUSINi e d temporarilan E n i y SILOE using connecting pneumatic transport lines with the LMA, especially when short- lived isotope e searchear s d Otherwise, ballaste d doublan d e sealed samplee ar s Irradiated m the primary coolant flow, in the reflector

As concern e GRRth s , applicatio nA hav fieldNA e f beeo s n numerous - Industry electrometallurglcal, chemical - university ground mining survey - judicial investigations

4 Suppor 3 f nucleao t r power programmes

Together with neutron radiography and y spectrometry, materials irradiation testing for nuclear power applications have made the biggest share of the GRR activity d thesan e usee togethear s r wite educationa th e hforemos th e on tl justificatiof o n research reactors' existence today

Nuclear power pacific use requires proven technology and educated people Education, as helped by the GRR is reported herebelow As concerns Irradiation e developmenth o t contributioR GR te programmesth f no f woro s bee t ha klo n a don, n ei those reactors bot r domestifo h d foreigan c n programmes concerning whether power, shielding, or instrumentation fields, and various fission power reactor lines (graphite moderated 2 cooleCO , d reactors water reactors, either PWR r BWRso s , LMFBRs, HTRs) Irradiation service for prototypical fusion reactor development is just starting m SILO A sketc Ea typica f o h l Irradiatio g arrangemenri n 5 s showi g t fi n i n

) i shielding studies were don MELUSINm e s verit t y a Estar t

114 ) ii fuel, control d structuraan , l materia l functiom testin ma s bee f e ha go nth n SILOE from its start m 1963 and that reactor has been repeatedly updated and upgraded through years for that purpose (see table 5) [2,3,7] The fuel experiments have been conducted in 2 different types of irradiation devices, a list of which is shown in Table 5

- coolant loops whenever forced convectio s necessarwa n o coot e y Ih l tested sample

- capsules whenever natural circulation inside the rig test section was sufficient

As a typical scheme, experiments for a reactor line have chained together along the following development [8]

- materials behavio y radiatior d undean n rn Isotoplc changes buildP F , - up and transport, swell, creep, change in thermal or mechanical properties

- steady state runs at nominal power density and in representative neutron energy spectrum, temperature and pressure conditions

simulatio f o norman l power plant operating transients start-up, coastdown, shutdown, daily load follow-up, marginal instant power adjustment to grid demand

- destructive testing built-in clad failures, los f coolanto s , reactivity insertion ramp, simulatio f o severeln y degraded core conditions, complementaril o safett y y test reactors work

a rule s A , those experiments have implied shorte d shortean r r irradiation durations but greater preparation and then unfolding work, more experienced experimental teams, more sophisticated instrumentation, more compute d (datai r a processing, control of timing, ) Whenever for that power testing, high power was not necessary, MELUSINE reacto s beeha r n used PWRs' simulant neutron energy spectrum experiments burnable poison, recycled poison presen n I reprocesset d recycled fuel, LMFBR natural cooling of a large debris bed simulant of a molten core[2]

Disposal of high activity hot cells and of a on-line Fission Product collection and analysis laboratory became at some time prerequisites to sustain power r&d work

III) r&d work in power reactor instrumentation has also been done in the QRR, mostl t MELUSINa y r radiatioEfo n monitors, mostl t SILOa y r lo E thermomechanlcal Instruments see [9,10]

5 Neutro3 n radiography

That powerful 'echnlqu s bee ha en continuou i n s sincdevelopmenR GR e e th n i t 1969, see [11,12,13] It gives an Information complementary to that obtained by y radiographyra classica y r o X l , whenever applicabl n GrenobleI e s becomha t I , a e standard reactor use since 1970, either for out-of-pool examination (first evaluation was wit a MELUSINh E extracte n bead n mi 1968 r m-pooo ) l irradiation rigs examination (SILOE, 1968) Since 197 6a MELUSIN n Ebea s beeha m n devote o unirradialet d d materials examination Sofar n radiography m Grenoble has consisted m using the transparency propert e objecth f o yt under examinatio o thermat n l neutrons (col r vero d y t harge cold do t cop) y photographic picture throug ~ emissioß h n from n,/3 back-loll (Dysprosiu r Gadoliniummo r froo ) m s fueFP l

1 15 GENERAL VIEW The lower section is placed In a mobile waterbox for flux adjust- ment in relation to the core.

The coolan tl other circuial d san t are led out to the top of the pool by the upper section (electrical, fission gas, valve control circuits)

Tht of-pileou connectx ebo e sth upper sectio coolane th o nt t (oop, and equped with the safety devices necessar o ensurt y e uninterrup- ted refrigeration

Schematic

1) Section at core level 2) Mobile waterbox The electrical instrumentation 3) Lower section rack contain functione sth s 4) Connection to water box - heater power supply. 5) Electrical connection - temperature ancTflowrate record- of lowe d uppean r r ing sections - control and regulation signal 6) Upper and lower transmission, section connection, - automatic safety action, coolant loop 7) Upper section, with heat exchanger 8) Electrical connection of upper sectioo t n the control panel 9) Envelope with heat exchanger 10) Control panel, with power suppld an y safety functions 11) Coolant loop 121 core

FIG. 5. Typical arrangement of a power programme irradiation rig.

116 TABLE 5 - MELUSINE and SILOE GOINN O PASD G AN TIRRADIATIO N SERVICE SUPPORN I S F POWEO T R REACTORS R & 0 PROGRAMMES historical sketch

INSTRUMENTAL SUPPORT REACTOR LINE TEST OBJECTIVE Irradiation rigs Reactor upgrade Instrumentation

UNGG s (Natga , .U cladding + struct, materials: CHOUCA furnaces 1963 SILOE power raiseM dM O t3 <> cooled, graphite) tensile, resilience, swell, induction furnaces 1965 in 1967 (1955-1972) creep, transition temp, french programme high temp. C behavior

AGR Graphite corrosio hoty nb , Anglo-french CO Loop 1969 CO

HTR + GC HTR pebbl d fueebe l irradiation Induction furnaces SILOE raise 35MW(19o t d ' rl) french programme pebble bed fuel failure TUMULT 1972 x fluma x available 14 ( 1968-1972 ) then US KP releas analysie+ s COMEDIE 197 loope (H 5) thermal : 4x10 fast : 4.5X101*

PWR 1973-198 irradiation, 6Ni , Zy , SS ; CHOUCA furnaces ( french programme : 40 thermal conductivity ,FP releai e CYRANO capsules 1970 SPN therma( D ) n l units ordered within power ramps •*• cycling onto AQUILON capsules 1973-1976 calorimetery s SILOE high core stool 2 m long pins, FCI, BOUFFON/GRIFFON caps. 1971-1972 (= 1970) (1977) power transients, PUMT JE P loop 1979 SAGA Sept. 1980 10 years ) clad failure P transpor,F t fuebundled ro l s 1980-1985 MELUSINE primary flow Pu recycle O U fuel d ,G . uprated (1984)

LMFBR, 1964 and on LOF, TOP experimentsK ,A , power CYLEX capsules 239 p fasN detectotn r ( french and transients, clad failure, DND THERMO PUMP Loop Th (1972) multinational pgme ) FAHR (bed behavior)n pi ,7 CELIA Loop bundle exper. ELISE Loop Collimatlo nf boto ratio hD L/ in-poos d out-of-pooan l e changebeamn b l n ca s d by diaphragmmg but at the expense of the exposure time, also, neutron energy filtering e MELUSIN cadone th b nn eo E out-of-pool beam, restrictin subthermao t g l energy range (Be filter) Parasitic y rays from core are also filtered As another use, counting of so much colllmate d transmittean d d neutrons yield quantitativa s e analysi object[13e th f o s ] so far, it has been used only in out-of-pool applications

Tomographie applications are presently under development this technique proceed y numericab s e reconstructior, l f isotopo n e concentratio p fro mma na numbe f o r transmission photographic pictures, taken at various angles and densitometer numenzed

Sample uses ol neutron radiography at the GRR have been

- post-irradiation examination of tested nuclear fuel with enlargement by a profile prelector accurac f dimensionao y l measurement m Thi^ sn sho O dowca s5 w o t n transport of nuclear fuel caused by the experiment transient, dimensional changes (diameter, profile, length,, swell) [12]

examinatio f nucleao n r industry material prio o Irradiatiot r n (fabrication control) quantitative control of fuel or burnable poison density In fuel elements at the assembly phas , efabricatio n contro f irradiatioo l n rigs prio o irradiationt r ] 3 1 [

- non-nuclear industry control University lab devices, polymer powder explosive actuators of space Industry

y spectrpmetr 6 3 y

t jus no a standarThit s i s d gammagraphe th f o e y us techniqu e th t bu e Information contsined Into the source, y spectrometry differs from y radiography In that the object examiney sourc e th es I dItsel f Thi s typicallI s l neutroal e cas r th y fo e n activated material and burnt fuel Multichannel y counting combined to very much collimated Inspection, yields the local density of the emitter and Its precise location y attenuation by the object must generally be taken into account

At the GRR, the y spectrometry benches (SILOE, 1972. MELUSINE, 1974) are mounted acros e pooth s l wall, whic s usea grosI h s a ds collimatoa shield s a e th d , an r object being e channeplaceth n o d l pool-ene counteth d an dr outsidf e pooth Re f l o e [14] tor example gives a detailed description The attached figure 6 is excerpted from this

At the GRR, more and more Information on the y emitting object has been obtained with years by better data unfolding and more numerous Inspections .

- coaxial scan of cylindrical fuel pins (grossly constant diameter)

- single diameter sca f cylindricao n l pins , yieldin, g radial distributiof o n emitter crosa n i s s sectio r instancefo . n , this show migratioP F s n betwee successiv2 n e examinations

- cross-sectional tomography of cylindrical pins since 1981, using a limited number of diametral scans . this yields isodensity contours

In the case ol burnt fuel, y emitter identification and density sizing enables to unfol e variouth d s neutron flux spatial distribution se fue th see l y b throughoun e th t irradation duration, the FP species densities acting as a spectrum of memories Among other uses, y spoctromotry has been used at the GRR to - measure local fuel burn-up and power density - trac e fueth e l fragments transpor m cas f tdestructivg o eri insid e th e e experiments

118 Irradiation Ovice Examination Bench

Main Pool

Acquisitio d Controan n l Unit

.*>l Où o. N r co a m Coi l! fr' •VSS^»3 Working Pool • ^/>,w»•• « "u «.

Reactor Core

FIG . Gamm6 . a spectrometry apparatus

3. 7 Non-nuclear industry-supported research

s heri It d wore r& Intenden industrieI k e th o direc n s y relate a de n I swa th t o t d masterin f nucleao g r power, productio f radiationo r defensno e against radiationf o e Us . research reactor r routinto s e industry activitr fo f concer o A s heri yt NA eou f o n e likus e mining industr n grouni y d survey.

Aa rules , basic researc n Franci s i h e seldo ma par t that industry plays alone, t i associate t bu s wit statha e body like CEA, CNRS, INSERf/ n n suc I R h. . GR , fiel e dth beams have been mainly use : dstud f amorphouo y s materials (glass, microelectronics industries) , study of electrical and magnetic properties of electronic components candidates.

Non-nuclear Industry has used the GRR's at the developmental stage mainly for the neutron activation or radiography services : NAA for metallurgical development (AI alloys) n radiograph, n destructive-examinationo n i y r spacfo n e industry (explosive actuators) , enhancement of gems. The spent fuel pools have sometimes helped for y ray uses . polymer cross linking, . .

6 Educationa . 3 d traininan l g uses

contributioR ThGR e o thest n s alreadha e y been covered quite full n [15]I y : the GRR have been permanently used for :

- information of the public at large : reactor safety, uses of neutrons, radiation problems in power plants, ... Of concern are the acceptance of nuclear energy by the recognitioe th publi d s manan cit f no y beneficia s safetit f lo y use d recoran s d Toure ar s organized under 2 forms : on-purpose tours and open-house days . Because of Its lower radiation level despite its power operation, MELUSINE has taken the biggest share of that duty

- training of power plant nuclear personel [15] ; It consists In neutronlc pratical work witSILOETTe th h E reacto : rreactivit y contro f coro l e fuel loading, neutron flux mapping, control rod worth measurements, void coefficient measurements; it consists a classrooals n I o m physics e poweperceptioth w r ho plan f o n t run n normai s l M

s,mulato, and emergency operation by use of neutronlc thermal hydraulic plant simulators (presently 3 reactor types simulated) (photo In fig 7)

- educatio t graduata n e level besid e abovth e e reactor pratical wort a k SILOETTE, some Grenoble nuclear graduate students come to the GRR department to do project or graduate MS/PhD thesis

n Dope 9 3 d silicon production

Transmutatio l o silicon n into phosphorou y neutrob s n activatio s i weln l documente e internationath m d l literature

The n doping range the GRR have done with sofar covers the field of power electronic components like diodes, thyristors) 16 f

Thermal neutron fluenc s monitorei e d with periodically recalibrated SPNOs i t I s made uniform, azimuthaly by rotating at constant speed the ingots and axially by using flux correcting filters Much automatization is aimed at on the production line (photo in fig 2)

0 Experienc1 3 n researci e h reactor economics

More than 25 years of research reactor operation and development at Grenoble has provided knowledge in all sorts of relevant costs and cost structures

- reactor operation, maintenance, backfilling, uprating, upgrading - reacto d irradiatioan r n rigs data processing cost - irradiation cosd rigr& st

4 SAFE ENOUG D COMPETITIVHAN E MULTIPURPOSE RESEARCH REACTORS

Offering some neutro nt jus useno t s i enougs a countr f I h y choose o embart s k a constructio n o a researc f o n h reacto o sustait r s scientifiit n d technologicaan c l development, that reactor, becaus s nonethelesi t i e costla s y machine d betteha , r have a good safety design higa , h availability factor potentia potentiaa d an lr latefo l r structural changes because of the changing demand The history of the GRR development is one of continuing upgrading and uprating to ensure higher reactor reliability, better Irradiation techniques and more Informative analysis techniques the way those were obtained at the GRR has been reported In several papers [2,3,4,71

Open core, swimming pool compact core reactor typs beeha egooa n d choice particularly becaus f easo e yo especiall s acces e cord th an er o t sfo y

- carrying out of the versatile power experimental programmes - information of the public - adaptability a soun f onc o e tan dth s eI k designe b e contentth , n ca s easily replace r upgradeo d d when needed

Multipurpose steady assignment has certainly been ambitious but It has allowed to quickly transfer technological advances from one field to another examples at GRR are multidetectors, mastering of low temperature techniques. With such choices, the Grenoble research reactors have been a privileged place for scientific and technical advance

121 REFERENCES

Research reactor use at large

[1] Function and utilization of the trench research reactors, COLOMEZ and MAS, in Revue Générale Nucléaire, France, 530,6, December 1981

C2] Upgrading and utilization experience with SILOE, OSIRIS and MELUSINE reactors pasd prospectsan t F MERCHI , IAE l a A t e ECopenhage n seminar, September 1985, (IAEA-sr/119-38)

[3] Incentives for recent power uprating and improvements of the french research reactor F MERCHIs E IAEA meeting, Vienna y 197Ma , 8

Neutron beam research

[4] Fitting SILOE and MELUSINE reactors to needs in neutron beam research BAAS et al , ENEA Symposium on research reactors prospects, Grenoble, November 1977

4 bis[ ] SILO competitivEa e reactor with potentia n beal m upgrading 198A CE 5, internal report

Radioisotope production

[5] see ORIS publications, Saclay, France

Neutron activation analysis

[6] Neutron activation analysis at CEA, LAVERLOCHERE et al, Dpt of radlolsotopes. Radioisotopes applications group, 1965

Support of nuclear power programmes

[7] Experience accumulated at Grenoble In the adaptation of the research and materials testing reactors to experimental programmes as well as In the development of Irradiation techniques, F MERCHIE et al , IAEA meeting, Juelich, August 1981

[8] Experience accumulated on nuclear materials Irradiation testing with the CENG reactors, F MERCHIE, Iran Atomic Energy Authority sponsored meeting, Teheran, April 1978

[9] The influence of the neutron spectrum on the embrlttlement of steels for reactor , IAE l a A t e Technica S vesselMA , s l meeting, Juelich, September 1979

[10] The instrumentation of the Grenoble research reactors Irradiation rigs, R LLORET and JF VEYRAT, SPG/Sedtl/523-83

12: Neutron radiography

[ l1 ] Neutron radiography. Journées d'informations électro-industrielles CEA-EdF, Grenoble, October 1969

[12] Neutron radiography at Grenoble: a complementary qualitative and quantitative control means for irradiated fuel, F.MICHEL and J.JEGAT, Neutron radiography 1st international conference, San Diego, USA, December 1981

[13] Industrial contro f materialo l s usin n bea a gm fro e MELUSINmth E reactoe th t a r CENG, PLOUJOUX and DUCROS, 7th intern, confer, on NDE, Grenoble, January 1985 y speçtrometry

[14] On-slte NDE of Irradiated nuclear fuels using y spoctrometry, G. DUCROS, 7th international conferenc n destructivno n o e e examinatio n i nuclean r industry, Grenoble, January 1985

Educational and training uses

[15] Training with SILOETTE reacto d associatean r d simulator e CENGth t a s, M.DESTOT, IAEA Copenhagen seminar, September 1985, ( IAEA-SR-1 19/44)

Silicon n doping

[16] Neutron doped Si In Grenoble reactor facilities, F.SCIERS and J.F.VEYRAT, 3rd Int. n transmutatioConf n o . , CopenhagenSI f o n , August 1980 . Plenu,ed m Press, New York, 1981

23 HUNGARIATHE USE OF N WRSZ-M TYPE RESEARCH REACTOR

PRODUCTIO ISOTOPEF NO S

T. LENGYEL Central Research Institut r Physicsfo e , Budapest, Hungary

Abstract

a serie Onf o ef seveo s n papers describin e activitieth g e th f o s Hungarian WRSZ-M typ M5 e W reacto e presentedar r e reactoTh . s i locater t a d the Central Research Institute for Physics. The activities include 1) Production of isotopes, 2) Application of reactor-produced radionuclides for industrial and environmental investigations, 3) Nuclear structure studies using fast , neutron'y(n r ) reactionsfo n ) Reacto4 , r neutron activation analysis, 5) Hot atom chemistry, 6) Testing of structural materials, and 7) Neutron physics. These serie f papero s s presen a vert y comprehensive summary of the reactor activities.

INTRODUCTION

Distinct steps of radioisotope production can be distinguished in genera therd e differenan l ar e t approache e realizatioth r fo s n thereof. However ,commonlo n ther e ar er uniforml o y y valid rules for solving problems a radiochemist has to face with in the course of isotope production: intentions, facilities and requirements differ and in most of the cases a compromise is to be aimed at. Anyhow a decisio , e takeb e s n grantea th n ca nf o dl al onl f i y possible achievement e considerear s e mosth td s propei an d e on r chosen. With a little exaggeration we may call this philosophic concept as the elaboration of the strategy of production.

IRRADIATION FACILITIES

Isotope production starts with irradiatio f properlo n y chosen targets.

In principle numerous possibilities exist but in practice the f reactoro e us cyclotrond an s e considereb n ca s d onl s beina y g wide-spread.

125 e higTh h cos f operatino t cyclotroa g n result a furthe n i s- re r striction of the facilities possible: in most of the countries the specially developed research reactors offer the only but still efficient sourc r performinfo e g activation.

Albeit nowaday e maisth n tren n applicatioi d f radioisotopeo n s i s shifted to those of relatively short half-life, the sealed sources e industryth use n i d , agricultur d medicinan e e contain nuclides which warrant, a more or less constant dose rate.

Providing tha productioa t n centre endeavour meeo e t demands th t s e customeroth f n thii s s broader sense e takeb ,f o o t ncar s i e assuring the possibility of both short and extended irradiation periods .

Short irradiation e performear s d usuall y than e sucwa i y th t a h irradiated target e reacto th e take ar f s rof n durin e operatioth g n thereof, in accordance with the schedule of production and de- livery.

In this case the (A2) yield of the radioactivity induced ex- pressed in Bq units can easily be calculated with the aid of the well-known e formulth r fo a

R / c 3 S — —— 2 R — Sl—— process

, -O.69. T .. .. , , ,, f -0.69T = 6.02xl024 -i- 1-exp — = — — = /7/7(VVA )** M $ n n 1-exp - Al L 2 (

(1)

A different treatmen e appliee b cas th f o long-liveo t en i s di t d isotopes.

Since most of the reactors operate discontinuously, having shut- down at the week-ends or maintenance intervals inserted between operation periods e long-terth , m irradiatio e regardeb o t s i dn

126 n ainterruptea s r thid Fo ones. cas modifiea e d relation applies that take e discontinuouth s s irradiation into consideration: r n-1 n 1 1-exp -0.69T exp(^^).-0.6+ t 9 (Z (A2>d = (A2>* Ml .. T 1= 12 2 1 = 1 J t, J (2) e madw mentioo w n e no o Ut np what kin f advantago d e energth e y dependence of the activation cross section may offer.

Tabulated values of activation cross sections usually refer to thermal and/or fast neutrons.

There are neutron induced nuclear reactions, however, which re- veal cross section y orderb s f magnitudo s e e epitherhigheth n i r - mal neutron energy region as compared to the thermal one.

By choosing the proper position inside the core or in the vicin- e insufficien th e e madreflector b th f o en itf o ca y e t,us modera- e samtioth ent a timtha s i et advantageous froe pointh mf vieo t w n increasino g "parasitic" epithermal neutron flux. Such considera- tions for improvement of the specific activity are rather rarely taken into account although they potentially offer favourable chances.

CHOIC D PREPARATIOEAN F TARGETSO N , IRRADIATION

One of the most important assessments in production on isotopes e mose choicith th st f o epromisin g target material. Circumstances influential in making decision are motivated in this respect by many aspects.

Principle consideration e focusse e ar thermas th n d radiao dan l - tion stabilitie e materialth f o s s aptnesit , r easd propefo san y r processing and - a not negligible demand - on the purity and accessibility.

Generally spoken these requirement e fulfilleb n ca s dl firsal f o t by using elementary targets or oxides, prevailing in solid form.

127 I should like to remind you that these concepts are guiding rules only, sinc r instancfo e e productio requireI e irradiaf o nth s - 12 5 tio f pressurizeo n d xeno s and ga nn addition i , t lo , a ther e ar e of cases which cannot adopt target materials of natural isotopic abundance.

These latter ones request the use of materials isotopically en- riched sinc e demandth e s towards radionuclidic purity and/or spe- cific activity are unfeasible in other way. o specifiTw c technique y disregarsma d this practice, namele th y neutron-induced fission reaction and the Szilard-Chalmers process, but these approaches raise quite different problems of special, keen-edged separation procedures d thian , se regarde b issu n ca e d as being far beyond the scope of this lecture.

The technique of encapsulation of target materials is usually the same. Some special accomplishments are, however, worth mentioning. Simple but unique courses are applied by using cadmium-foil wrap- e e targeimpacth th pin f f f faso i o tg t neutron s preferrei s d whil e therma th tha f e suppressedo b t lo t one s i s d speciaan , l encapsulatio e highls needei nth f i yd efficient cooline th f o g target material during irradiatio s indispensabli n r targeto e s for high-activity sealed sources are to be dealt with.

However, all these implements have become already routine practice

PROCESSING OF IRRADIATED TARGETS

After having finished irradiation and n speciai , l cases aftea r distinct coolin f short-liveo d g ri perio t - n ordege by (i ddo t r products) the processing should be started as soon as possible.

This seems to be important from the point of view of maintaining specific activit s hig a ys possibl a h a requiremen - e t generally existin d sometimean - g n ordei s o avoit r d radiolytic decomposi- tion .

128 The processing consists mainly of proper purification (separation) procedures mose ,th t commonly used being distillation (sublimation), extraction n exchang,io d precipitationan e .

The common feature of these separations can be conceived in the fact that usually trace amount f radioactivo s e materials should be selectively separated from inactiv r radioactivo e e matrices. This establishment is valid first of all for processing radio- nuclides obtained via nuclear reactions proceeding with change in atomic number.

However, these special tools used in radiochemical separations are now well elaborated and in spite of the continuous further effort r developmenfo s o basin t c change n technologiei s s being alread n practici ye expected b n ca e , though production centres prefer occasionally slightly different approaches.

Generall e experimentay th spokenf o t ,ou l techniques adopted those can be regarded as being the most suitable ones which beside sim- plicit d selectivitan y y eliminat t leasa r to e minimiz e formath e - tio f radioactivo n e waste d radiatioan s n hazard.

SOME EXAMPLE F ISOTOPO S E PRODUCTION

Let us briefly review the production of some representative radio- nuclides chosen at random. havr I es hig a broa d he an us activitd o C y sealed sourcen i s e industryth r radiographifo ,l firsal f o t e investigationsn I . order to obtain proper exposure it is necessary to have as high specific activit s possibla y e sinc e dimensionth e e activth f o es part usually do not exceed 2-3 milimeters.

This can be achieved by irradiation of rather thin metal plates, minimizo t o s e absorptio f neutrono n d settinan s g these together only after having irradiation finished. Finally the active part is placed into stainless steal holder and argon-arc welded.

29 I and I, the most commonly used radioisotopes in nuclear medicin e produceb n ca ey irradiatin b d s targeta g s pressurized d fusean xeno ds ga telluriun m dioxide, respectively, makine us g nucleae th f o r transformation followin e (n,yth g ) reactione Th . separation of the carrier free radioiodines is performed by wet y distillatiodr r o e volatilth f o n e products. b havY e alsd Cwide-spreaa oan r s radiopharmaceuticalsa e us d , Since these nuclides are produced via (n,y) reaction and the high specific activity is of outstanding importance, isotopically en- riched targets are used because the natural abundance of both Cr and Yb is relatively low.

c complexeT s have revolutionized diagnostic investigationy b s rendering possibl e imaginth e f humao g n organs usin gamma g a camera.

e short-liveTh d technetiu s deliverei m devica n i d e called radio- nuclide generator together with its longer-lived parent isotope, , 9fro 9Mo m s separatewhici e customet th i h y b d r using Chromato- graphie technique.

In order to obtain injectable solution the elution should be performed wit minimua h m volum f sterilo e e saline e procedurTh . e requests therefore radiomolybdenu f extremo m e high specific activ- ity that can be prepared by the fission reaction of uranium and following extractive separation.

130 Table I.

Radio- Nuclear Processinq Tarqet . , , Remarks nucl ide reaction t, t e p / s / produced used

2

32P /n,p/ MqSO. ion exchange + + . pret i cip c.f. S C-.C1, dissol+ . Z D -t- aqueous extr.

42K /n,Y/ K ,CO di sso L . in IIC1 -

51Cr /n,Y/ BaCrO. ion exchanqe Cr enriched target 6 °Co /n,Y/ Co encapsulation and as sealed source argo c weldinar n g 64 Cu /n,Y/ u C dissol1 HC n i . - 65 - Zn /n,Y/ Zn dissol . in HC1 82Br /n,Y/ n exchanqio BaBer -

86 Rb /n,Y/ Rb2CO3 dissol. in HCl -

9 °Y /n,Y/ Y?O-> seeds -

99mTc /n, Y / —— •- Titanium sublimation c.f. molybdenate C E / / 125I /n,Y/ —— »• Xe compressed dissol n NaOHi . + + acidic dist. c.f.

131 I /n,Y *— •/ TeO^, sublimation or c f "wet" dist. *— • • 1. • , , EC 131Cs /n,Y— — / BaCCu dissoln io + . c.f., cooling exchange before proc.

169 1 fi fi Yb /n,Y/ Yb2O-. disso+ l. Yb enriched + complexing target 192 T Ir /n,Y/ Ir pellets encapsulation as sealed and argon arc source welding 198 Au /n,Y/ Au dissoln i . low flux aqua regia, irradiation réduction and colloid form. 203 Hg In, Y/ HgO dissoll HC n i .

131 APPLICATIO REACTOR-PRODUCEF NO D RADIONUCLIDES INDUSTRIAR FO ENVIRONMENTAD LAN L INVESTIGATIONS

K. LEHOFER . BIRT , Ö Central Research Institute for Physics, Budapest, Hungary

Abstract One of a series of seven papers describing the activities of the Hungarian WRSZ-M type 5 MW reactor are presented. The reactor is located at e Centrath l Research Institut r Physicsfo e activitiee Th . s includ) 1 e Productio f isotopeso n ) Applicatio2 , f reactor-produceo n d radionuclider fo s industria environmentad an l l investigations ) Nuclea3 , r structure studies using fast , n'yneutro(n r ) reactionsfo n ) Reacto4 , r neutron activation analysis, 5) Hot atom chemistry, 6) Testing of structural materials, and 7) Neutron physics. These serie f papero s s presen a vert y comprehensive summary e reactooth f r activities.

e Institutth n I f Isotopeo e e Hungariath f o s n Academ f Scienceo y s Divisio f Isotopo n e Application severay-emittind an - ß l g radio- nuclides, produced in the nuclear research reactor are regularly applie s tracera d r industriafo s environmentad an l l process anal- ysis.

The mos, t Sc commonl , K y , S used , 6 P radionuclide4 , 2 4 Na 5 e 3 ar s 2 3 24

_ 82 86 _ D , 95 ,llOm 76 , „ 65 131_ 51 „ O 56_Cr64 14 M „, Mn/ Cu/ Zn, As, Br, Rb, Zr. Ag, I,

165 198 203 La140 Dy, Au, Hg, . Thee producear y y (n,yb d ) reaction from appropriate targets and after neutron irradiation they are chemically transformed into suitable chemical form. They have generally short live which makes possibl e fasth e t elimination of radiation after investigation. The usually applied activities are between 1O-10O mCi /O.37-3.7 GBq/ depending on the tested technology.

From among methods of industrial and environmental isotope appli- cations identificatio f substanceso n , determinatio f materiao n l movement, detectio f faultsno , measuremen f componeno t t concentra- tion, determination of the quantity of substances by isotope dilution, determinatio f wearino n g rate, homogeneit f mixtureso y , flow rates, characterizatio f flowinno g stream residency b s e time distribution, determination of diffusion rates etc. can be men- tioned.

133 s regardA fiele th sf applicatio o d n many branche f industro s n ca y be mentioned.

Duration tests were carried out on several hundred milling balls labelle measuro t d o witC eh their wear rate during cement milling. resula s A n optimuta m compositio balf no l materia s determinedlwa .

e locatioTh f leakago n f telecommunicatioo e n cable s determineswa d by detecting the escaped and absorbed methylbromide tracer, inject- ed previously into the cable shell. The flow rate of material transport was measured in rotary furnaces of cement factories, a isotopeusinL g 14. 0Flow rate measurements were also carriet ou d in other industrie o calibratt s e false flow meters.

Residence time distributio s determinewa n continuoun i d s reactors for artificial alcide resin production, for caprolactam polimeriza- tion, for glass melting in sheet glass production, for rotary furnaces in the charcoal industry and in waste water purification pool chemicae d towerth an s n i s l industry etc.

e relatioTh n between homogeneit mixind an y gs dependenc it tim n i e e on the type of the mixer was characterized in the artificial coal production process productioe th n ,i f cemenn petrono i d tan l pow- der fluidization tanks.

Segregation was studied in the fluid transport system of PVC granules. Mercury content was determined in a concentration of ? 7 — 10 — 5 to 10 g/cmj in caustic soda, sodium chloride solvent, hyd- rogen gas, chlorine gas, rinsing gas and wash water passing out e alkaloth f i chloride. Isotope dilutio s appliei n electron i d - lysis cells to determine the real mass of metal mercury.

In metallurg e fusioth yd homogenizationan n processes were inve- stigated with radioactive tracers .A simila r experimen s cartwa - ried out to study melting time and solidification in continuous casting to clarify the effect of pulling speed, cooling rate, steel sord crosan t s sectiodepte th f crater o hn no e resultTh . s wil usee e facilitiesb ldesigo th t w plad ne f o na n .

134 Various radionuclides have been use o studt d y diffusion ratd an e migration rat radioactivn i e e waste disposal. Investigations were carried out for measuring migration rate through engineered bar- rier d claysan s .

Co, Cs and Am radionuclides as sealed sources are exten- sivel e yinstrumente th use n i d d nuclear system r procesfo s s con- trol.

Though not connected with radionuclides here we must mention tharesearce th t h reactoadequatn a s d flexiblrwa ean e facility where various devices and methods for safeguards and in-service inspections of the fuel and reactor components could be develop- ed and tested. E.g. a very efficient underwater viewing device comprising an optical telescope was developed and proved to be applicable als t nucleaoa r power stations mais It .n features are: high optical resolution, stabilized image, continuously variable magnification d insensitivitan o radiationt y . Other techniques, suc s Y-spectrometrya h , neutron counting, activation methods etc. are also developed with the help of the research reactor fuel and facilities.

135 NUCLEAR STRUCTURE STUDIES USING REACTOR FAST NEUTRONS FOR (n, n'7) REACTIONS

A. VERBS Central Research Institut r Physicsfo e , Budapest, Hungary

Abstract

One of a series of seven papers describing the activities of the Hungarian WRSZ-M type 5 MW reactor are presented. The reactor is located at the Central Research Institute for Physics. The activities include 1) Productio f isotopeso n ) Applicatio2 , f reactor-produceo n d radionuclider fo s industrial and environmental investigations, 3) Nuclear structure studies using fast neutron for (n, n'y) reactions, 4) Reactor neutron activation analysis t atoHo m ) 5 chemistry, ) Testin6 , f structurao g l materials) 7 d an , Neutron physics. These serie f papero s s presen a vert y comprehensive summary e reactooth f r activities.

Recently new theoretical models describing nuclear structure have been developed initiating further experimental investigatiof o n nuclei addition I . o traditionat n l methods suc s nucleaa h r reac- tions produced by accelerator neutrons, the reactor neutrons, especiall e (n,n'yth a vi y) reaction promise informatiow ne d o t n be gained.

Ahmed et al. /NIM 117, 533 /1974// described an external neutron beam facility usin a wateg r moderated research reactoa s a r neutron source. They used filtered fast neutron beam for measur- ing y-ray spectra froe inelastimth c scatterin f neutrongo e th n o s nucle f smalo i l weight samples. Abou n year . Molnâte o t al ag s t e r starte o built d experimentan a d l setup simila o that rf Ahmeo t d et al. at the research reactor of the CRIP. At a reactor a well defined direction and relatively high flux density /about 10 f fas/o t s neutronc me achieved1 -b - 2 n ca s . This result gooa n di s geometry for the shielding and good statistics for the y-ray spectr y runnina da usin e gon g time. Besides these good features the continuous neutron spectrum causes some complication in the interpretatio resultse th f o n . These features combined wite th h n selectivno e excitatio f nucleo n i giv a usefue e lth toor fo l examination of low-lying levels of the nuclei. That means we can excite all levels of the stable nucleus in the range of O-4 MeV and I - I - 6 in contrast to the other types of excitations.

137 e th e spigroune f th th e spio n s f th i do n Her s I stati d I e an e

exciteQ d one.

Theoretically this facility can be used for the determination of all nuclea r grou ou s measure rha pw nucleus a datno f o o at d p .U only transition Y~ray energies of the nuclear levels, intensities and angular distributions. From thes determinen ca dat e aw e th e energies and spins of the nuclear levels, the branching ratios multipole th d an e mixing e ratioy-rays.Thesth f o s - eim date ar a portant for the new nuclear structure models. We have turned our attentio mediue th o mt n heavy nucle d investigatan i 0 aroun4 = Z d- ed the 94 '9 8 'TO OM o and 9 6Zr nuclei. The molibdenum isotopes form a transition chain, i.e. they become more deformed with the grow- ing neutron number. Using this metho e determinew d d manw nucne y - lear data and described them within the framework of IBM-2 /Inter- acting Boson Model/ with configuration mixing in the case of ' Mo. The Zr nucleus seems to have some a-clustering charac- ter n thiI . s cas e discovereew w transitionne d d determinean s d other nuclear data which can be a basis for new nuclear structure model calculations e seconTh . dr interes fielou N=8e th f o 2ds i t region. In this region there are some nuclei which exhibit shell model character. We determined again new nuclear data and we could giv e nucle C vera e yi d goowithian da B description e th f o n the framewor e shelth lf o ke futuremodel e reactoth th n I .t ,a r with increased powergoine ar o complet t ge ,w r techniquou e e with y coincidenc- e in-bead an d polarizatioy an ey- m n measuremento t s gain more informatio n nucleao n r level d transitioan s n multipolar- ities.

138 REACTOR NEUTRON ACTIVATION ANALYSIS (RNAA)

H. RAUSCH, A. ELEK, M. ÖRDÖGH, I. SZIKLAI Central Research Institute for Physics, Budapest, Hungary

Abstract One of a series of seven papers describing the activities of the Hungarian WRSZ-M type 5 MW reactor are presented. The reactor is located at e Centrath l Research Institut r Physicsfo e e activitieTh . s includ) 1 e Productio f isotopeso n ) Applicatio2 , f reactor-produceo n d radionuclider fo s industrial and environmental investigations, 3) Nuclear structure studies using fast , n'yneutro(n r ) reactionsfo n ) Reacto4 , r neutron activation analysis t atoHo m ) 5 chemistry, ) Testin6 , f structurao g l materials) 7 d an , Neutron physics. These series of papers present a very comprehensive summary e reactooth f r activities.

e CentraIth n l Research Institut r Physicfo e e WWR-th s S typ- nu e clear research reactor has been put into operation in 1959. Thus, RNAA could be initiated in I960, sharply after the starting up of the research reactor.

This microanalytical method has proved to be highly suitable for analysis of ultrapure materials used in the solid state physics and semiconductor physics, for studying the role and behaviour of e microelementth n biologicai s l substances als d r multian fo o, - element determinatio n rocki nmineralsd an s .

Advantages of the method are: the extreme sensitivity of detec- tioa e freedoth , m from blank e valuereagentsth f o se applicath , - n absoluta tio f o n e metho f analysio de simultaneou th d an s s cover- a broa f o d e spectruag f melementso employiny B . g radiotracer technique s possibli t i s o obtait e n important informatioe th r fo n optimizatio f manufacturino n d technologicaan g l procedures.

e KFK th RNAs i partlIn i A y organize n "Opea s a nd System Laboratory" that means that co-workers from different institutions having special microanalytical problems are welcomed in the laboratory for a certain termine. This may explain the broad spectrum of analytical themes occuring in our laboratory. Table 1 demonstrates e maith n analytical questions arising both from general research programs and industrial technoligies.

139 Table 1

SCOPE OF THE MAIN THEMES INVESTIGATED BY RNAA

1. Analysis of corrosion and fission products in primary coolants of nuclear power plants.

2. Analysi f ultrapuro s e materials, chemical manufacd an s - ture intermediates used in LSI microelectonic device production.

3. Analysis of bioligical substances in cooperation with clinics.

4. Multielement analysis in geological and rock samples (Moonrock analysis, REE* distributio n clai n y minerals).

5. Analysi f standaro s d material n internationai s l coopera- tion used for OES, SIMS, ION MICROPROBE calibration.

6. RNAA system developments, monocomparator standardization, computation, automation.

RE = RarE e Earth Elements

1. INVESTIGATION OF PRIMARY COOLANT

e organizatioIth n e nationath f o n l middle-term researc- de d an h velopment project (OKKFT) numerous radioanalytical characteriza- tion techniques have been develope o qualift d e primarth y y cir- cuit during assembling and comissioning periods at the first two unit f Pako s s NPP.

Thus, RNAA, gamma-ray spectrometry, particle sizin d microan g - photography were use o investigatt d e construction materialf o s e primarth y circuit e amounth ,compositiod an t e floatinth f o n g mechanical contaminants in the periods of circulated washing, hot conditioning, physical and energetic start up.

The aim of the measurements was to follow closely the variation in the amount and the removing of the mechanical contaminants depending on the technological parameters.

140 n Fig.I concentratio1 nelement w changefe a f so s withi e floatth n - ing particulate matter are shown during the first and second hot conditioning e figur th seee b n i nen thaca e concentratio t th I t . n peaks coincide with temperature transients.

10 10 15 June 1982

Fig 1. Corrosion products >-O.A5 urn

/$30___453_53J_

11.28 29 30 12.01 6 doy

CO £ jo total numbe particltsf o r —*——*— 0.8 n meo8ur n diameter 2.A4 10' 5.94

105

Fig.2 Number of particles t conditioninho t a g

141 e particlTh e sizing dat n Fig.i a 2 sho e samth w e coincidencf o e the floating matter peaks wite temperaturth h e transients. Par- ticle sizing turned out to be a simple and fast technique for controling the amount of insoluble products in the primary coolant,

In operating power units investigations have been extended to stud e corrosioth y n radioactive isotop d fissioan e n products amount which may occur both in solid particle forms and in dis- solve n formsio d . These product e comprehensivelb n ca s y names a d operating indicators.

In primary coolant microelement e originateb y sma mechanicay b d l and chemical corrosion effects as well as by introduction with chemicals. Furthermore particles may be arised by mechanical cor- rosion of the inner metal-oxide layers, by chemical precipitation of insoluble metal-oxides-hydroxides y crystallizatiob , y b d an n mechanical smashing of the ion exchange resin.

t coulI e establisheb d d thae distributioth t microelemena f o n t between the particle and dissolved ion form depends on operational parameters of the primary circuit. That is why they have to be in- vestigated.

n Fig.I e e schemfulth th lS f o eanalytica l process user charfo d - acterizing primary coolant is demonstrated. Particles are separ- e maith ate nn i sted y filteringb p . Filters havin pora g e size usede d 0.4betweear an m . 5y 1 Measurement0. n made ar n sboto e h fractions accordin e diagramth o t g .

e r variatioexamplth Fo 5 n Fig.d i ef radioactiv an o n 4 e isotopes are demonstrated in both separated phases depending on the PCP status.

The analytical program and measuring techniqes are developed in cooperation with the Radiochemical Laboratory of the NPP Paks and e resultth s have been presente t IAEa d A Specialist's Meetinn o g e Influencth f Wateo e r Chemistr n Fueo y l Element Cladding Behav- iour in Water Cooled Power Reactor [1-5].

142 SAMPLING

TOTAL BETAL - TECHN. WATER RAY MEASURED~ . ANALYSIS

DIRECT OAICJA^L RAY SPECTR| .

FILTERING /0.45

T jJ~ L R I [F FILTRATE n /PARTICLES/

NEUTROK ACTIVATION

REMOVAL OF fia- ("GAMMA-RAY K-ACTIVITY "1 SPiXTROMETRY

SEPARATION OF PARTICLE SPEC.ISOTOPES ANALYSIS

SEPARATIO* 0 N ItrCROPHOTO- FI S3.PRODUCTS GRAPHY

GA1OA-RAY AUTORADIO- SPECTHOM..TKY GRAPH!

ANALYTICAL RESULTF O S ANALYTICAL RESULTF O S TH1' FILTRATE THE CORR. PARTICLES Fig. 3 Scheme of the characterization of primary coolant

hour

Fig. 4 Radioactivity in 0.1 p m filtrate vs. PCP status

143 Öl

o o n

U A 1313 6 A 6 24 310 r A T M A A i 17 18 20 22 hour 8. Feb. 1983 9. Feb. Fig. 5 Radioactivity of corrosion products > 0.1 )Jm vs. PCP status

2. ANALYSI F HIGO S H PURITY MATERIALS

With ultrapure material s necessarwa t i s o investigatet y , among other parameters, the technological impurities and the local dis- tribution of impurity and doping elements.

The advantages and the wide ranging applications are demonstrated by way of results from radioanalytical investigations of any prob- lems arising from semiconductor technology.

The results obtained by RNAA combined with successive layer re- moval procedures demonstrate the impurity distributions in sur- face and interface regions of silicon [6,7], the introduction of impurities in ion implanted and diffused materials and the dis- tribution and segregation of contaminants in thin layer technology, e.g. oxidatio d Si^Nan n . growth [8,9].

To check the lateral distribution of the radionuclides on surfaces n thioi r n layers autoradiograph s alsi y o widely used e detecTh . - tion method makes it possible to illustrate the deposition of dop- ing and impurity elements in swirts, striations and defects in the crystal lattice, e.g. in silicon, resulting in undesirable crys- talline properties.

144 By chemical or anodic successive layer removal in depth analysis a resolution of 10 run, and by autoradiography a lateral resolu- tion of about 10 ym could be achieved.

High purity ground materials, electronic grade chemicald an s solvents investigated in the KFKI RNAA Laboratory are summarized in Table 2.

Among these ultrapure materials silicon and silicon based thin layers used in the microelectronical device production have been investigated most extensively. Numerous methods are developed to control technological intermediate samples such as diffused and implanted profiles, surfaces, interfaces, silicon dioxidd an e silicon nitride films as well as high purity aluminium oxide ceramics [10].

Tabl2 e

Ultrapure materials e investigatioTopicth f o s n

Silicon and determinatiof o n Silicon based thin layers - impurity elements - dopant distributions Gallium-Arsenide determination of -Phosphide - composition rate -Arsenide-Phosphide - impurity elements Al,Mo,W (5N) metals determinatio f impuritieo n s Al(Si,Mo)Si thin layeres determination of - composition and distribution - impurity elements based ceramics determinatiof o n - 35 impurity elements Chemicals determinatio f impuritieo n n i s - nitric acid - fluoric acid - basic acid - ammonium fluoride Solvents determinatio f impuritieo n n i s - alcohols - acetones - trichloro-trifluoro-etilene - toluene

145 Detection limits of the impurities investigated in silicon, sili- con based layers, chemicals and solvents vary in the range of ppb to ppt, as it is shown in Table 3.

The developments of radioanalytical methods are stimulated by the large numbe f microanalyticao r l problems arisine differenth n i g t technologies. Therefore, cooperation exists with numerous institu- tions , viz : Tungsram Research Institute for Telecommunication Microelectroni. cCo Institute for Semiconductor Physics, Frankfurt-am-Oder (GDR) Research Institut r Solifo e d State Physics, Dresden (GDR)

Table 3

DETECTION LIMIT ELEMENT CONDITIONS tppt]

Na 1 Sample preconcvacuu, x 0 m10 .evaporatio n K 66 Irradiation 17280s 0 Se 0,5 Decay perio~ 8640s 0d Cr 27 Measurement 2000s Fe 4700 0 imp10 . Np (.Tin .)

Co 13 FG 2 CT Cu 0,6 Canberra (Gc(Li = 13,6 r ), % Zn 330 *= 3.8-10^ 13 cn~2s~1 Ga 0,5 As 0,2 *^ = 32 Br 0,4 Rb 130 MO 83 Ag 18 Sb 0,2 Ba 390 La 0,3 Ce 12 Ta 4 W 0,3 Au 0,008 Hg 9 U 0,5

146 3. INVESTIGATION OF BIOLOGICAL SUBSTANCES

In the last decade there has been increasing interest in determin- e tracinth g e element medican i s d biologicaan l l materialsn I . our laboratory such investigations wer e paseth tcarrien i t ou d few years, in connection with different diseases.

Autopsy brain samples of patients suffering from Wilson's disease were studied together with control samples e regiona.Th l distribu- tion of copper and other trace elements were determined [11]. e coppeTh d enzymean r s containing copper play als n importana o t role in schizophrenia being also a disease of the central nervous system [12].

Our purpose was to contribute to the neutrobiology of the men- tioned diseases.

The distribution of silver in hair, nails, tooth and neck skin tissues of patients suffering from the endogeneous argiroses, a seldom occuring disease nowaday s investigate,wa n conjuctioi d n wit vera h y interesting opthalmological examination [13].

To help the understanding of the mechanism of the DBD chemotherapy applied with radiotherapy e brominth , e content f biopso s y samples of malignant tumors were determined.

Detailed investigations were carried out to study the distribution of trace and minor elements in different parts of ripe paprika plants since such data were hardly availabl e literatureth n i e .

Investigations concerning to the mentioned biological substances are mad n cooperatioi e n wite followinth h g universities, clinics and hospitals. Clini f Internao c l Medicine, Pecs Biochemical Institute, Medical University, Budapest Clinics of Psychiatry, Medical University, Budapest Departmen f Phtalmologyo t , Markusovszki Hospital, Szombathely Neuro-psychiatric Department of Jànos Hospital, Budapest

DB = DibromodulcitolD a ,cytostati c agent

147 ACTIVATION ANALYSIS IN GEOCHEMISTRY

During the last years russian moon samples were analysed by ac- tivation analysis. The samples arising from different districts of the moon, were fractionated in different grain size parts, and their aluminium, titanium, vanadium, iron, sodium, potassium, calcium, barium, scandium, hafnium, cobalt, chromium, lanthanum, cerium, neodymium, europium, dysprosium, terbium, ytterbium, and lutetium contents were determined. Also agglutinatese th n ,o earth unknown particles, were wors th i ek f o analysed m ai e Th . the investigation of the conditions developing the moon surface. e wors madTh n wa collaboratioki e n wite Geochemicath h d an l Analytical Institute of the Soviet Academy of Sciences.

For geochemical purposes the method of activation analysis was developed, too. A simple instrument is constructed for radio- chemical separatio f severao n l element e gamma-spectrometrith s c measuremen whaf o ts distrube i t e maith n y b dconstituent e th f o s activated rocks.

REFERENCES

. BogâncsJ ] [1 Marothy. ,L . Bakos,L Baranyai. ,R . Elek,A , H. Rausch, E. Szabo: J.Radioanal.Nucl.Chem. 88/1, (1985) 85-96 . ElekA . Rausch] ,H [2 : Progress repor n primaro t y circuit characterization at the first unit of Paks NPP. Central Research Institute for Physics, Chemical Department 6th Feb. 1985. [3-5] Research reporte OKKFth f To s project, 1983., 1984., 1985 Central Research Institut r Physicsfo e , Institutr fo e Atomic Energy Research . [6RauschH ] . Bereznai,T . Bogäncs,J : J.Radioanal.Chem. 19 (1974) 77-85 [7. GaworzewskiP ] . Kaiman,L . Rausch,H . Trapp,M : J.Radioanal.Chem. 52/1 (1979) 93-100 [8] H. Rausch: J.Radioanal .Chem. 3_3 (1976) 201-2O7 [9] H. Rausch: J.Radioanal.Chem. £4 (1978) 119-127 [10. RauschH ] . TörökSz , . Simonits,A : Izotopenpraxis1 2 , (1985) 6

148 . ÖrdöghM ] . Fazekas11 S , . Horvâth,E Ovary. I , . PogänyL , , I.L. Sziklai . Szabô,E : J.Radioanal.Chem No., 79 . l (1983) 15-21 12] A. Lipcsey, M. Ördögh, J. Fekete, E. Szabö: J.Radioanal. Chem. 88/1 (1985) 57-62 .13] I. Sziklai, M. Ördögh, E. Szabö, P. Râcz, I. Patty, I. Berta w resulte experimentaNe :th n o s l investigation of argyrosis Trace Element-Analytical Chemistr Medicinn i y d an e Biology, Vol.2. Walter de Gruyter and Co. Berlin, w YorkNe , 1983.

149 ATOT HO M CHEMISTRY AT THE RESEARCH REACTOR WWRS

K. BEREI . VASÂROL , S Central Research Institute for Physics, Budapest, Hungary

Abstract One of a series of seven papers describing the activities of the Hungarian WRSZ-M typ 5 Me W reacto e presentedar r e reactoTh . s i locater t a d the Central Research Institute for Physics. The activities include 1) Productio f isotopeso n ) Applicatio2 , f reactor-produceo n d radionuclider fo s industria d environmentaan l l investigations ) Nuclea3 , r structure studies using fast neutron for (n, n'y) reactions, 4) Reactor neutron activation analysis, 5) Hot atom chemistry, 6) Testing of structural materials, and 7) Neutron physics. These series of papers present a very comprehensive summary of the reactor activities.

Research reactors provide a valuable tool for studying hot atom chemistry, namely the chemical interactions of high energy radio- active atoms forme a resul s a df nuclea o t r recoil with surround- g atom moleculein d an s s existin n thermai g l equilibrium.

3 8 High energy replacement reactions by recoil halogen atoms ( Cl, o'j 1 ? ^ 19ft Br, I, I) produced via (n,y)/ (IT), (EC) nuclear processes with simple organic systems (substituted aliphatic hydrocarbons and benzene derivatives) have been investigated by a small team in our Institute.

The effect of the initial kinetic energy of the recoil atom, that of the moderation conditions, of impact parameters as well as of the chemical propertie e reactinth f o s g species have been exam- ined.

In contras e previouslth o t y widely accepted mechanistic model e paramounbaseth n o d e inertiat th rol f o d esteri an l c factors (impact parameters e e higcoursth th h n f i o eenerg) y interaction, e experimentath l result f thio s s group prov e decisivth e e influ- ence of the chemical properties and structure on the hot replace- ment processes by recoil halogens. Thus e.g. it was found that the bond energy of the atom or group to be replaced plays a con- trolling rolr replacemenfo e t processe t halogenho y b smonon i s - substituted benzene derivatives. Furthermore t replacemen,ho f o t

151 a heavy ato r grouo m n disubstitutei p d benzene derivative- de s pends also on the chemical nature of the second substituent as s relativit n o wel es a lpositio e moleculeth n i n . This reflects the influenc electrondensite th f eo y distributio e benzenth n i n e ring on the high energy reactions.

Conclusions coul e drawb d n from these studiee chargth n o se (neu- tral d energan ) y (<2 ) statOeV f reactino e t halogenho g s wela s l e approximatth n o s a e mechanis t replacemenho f o m t processes (atom - molecule collision, short-lived excited intermedier).

Some information could be obtained about the role of geminate recombination ("cage-effect") in the stabilization of recoil atoms by examining the effect of the chemical reactivity and of the long rang emediume ordeth f o r. Thi s importani s n ordei t r to differentiate between the genuine hot reactions and those of the thermalized recoil atoms leading occasionally to the same labelled products.

Such investigations extend our knowledge of chemical reactions towards energy region well above the conventional energies of the Boltzmann equilibrium. On the other hand, new routes for direct labelling of organic molecules are discovered which may e applieb r bio-medicafo d l purposes.

152 TESTING OF STRUCTURAL MATERIALS IN A RESEARCH REACTOR

F. GILLEMOT Central Research Institute for Physics, Budapest, Hungary

Abstract One of a series of seven papers describing the activities of the Hungarian WRSZ-M typ M5 e W reacto e presentedar r e reactoTh . s i locater t a d the Central Research Institute for Physics. The activities include 1) Production of isotopes. 2) Application of reactor-produced radionuclides for industrial and environmental investigations, 3) Nuclear structure studies using fast neutron for (n, n'y) reactions, 4) Reactor neutron activation analysis, 5) Hot atom chemistry, 6) Testing of structural materials, and 7) Neutron physics. These serie f papero s s presen a vert y comprehensive summary of the reactor activities.

The service lif f somo e e part f nucleao s r equipment s i limites d by irradiation damage of their structural materials. The effects of irradiation damag e detectear e monitoriny b d e changeth g n i s the solidity characteristics of the specimens placed in the re- actor. Ferritic steel impuritieP d s an wit u e especiallC h ar s y sensitiv o embrittlement e t cause fasy b d t neutrons t therbu , e are also some other structural materials in which similar pro- cesses may be observed.

The e numbesurveillancth f o r e specimens e placereactoth n i ds i r limite theid s veri an dr t yi siz importans o smalli s e d an , t indee o applt d y correct measuring method o thas s- tde none ar e stroye y theib d r inadequac humay b r no y carelessness. e heatinth On f o e g element e WWRSth f o -s reacto s bee- ha rre n place a closed y b d , temperature regulated irradiation capsuln i e which specimensmade from different structural material- ir e ar s radiate a 1-5x1 y b dV fas 0Me tl neutron/cE m - n 1ir dose9 e .Th 2 radiation months6 periode irradiate2- th e n ar O .s d specimens tensile, impac d fracturan t e mechanical test e conductedar s n O . the basis of these tests the irradiation toughness of the weld- ing e joint15H2MFth f o sA type steel used e countriewidelth n i y s became known. The methods of mechanical tests on the irradiated steel specimen e evaluatioth d an s n processe e alsar so bein- de g veloped further.

153 Th e e specimentestth n o s s irradiate e researcth n i d h reactor fore scientifith m c backgroun e surveillancth f o d ee testth t a s Paks nuclear power statio d weran ne utilize n constructini d e th g Hungarian surveillance lab and training its staff.

The reactor is used to test aluminium, too. For the reconstruction e reactooth f e succeedew r n developini d AlMn a g gn a allo d an y appropriate welding join e toughnesth t s characteristic whicf o s h are slightly enchanced after 5x1019 n/cm2 irradiation dose. Until now an AlMgSi type alloy was used, the welding joint of which became brittle after irradiation. The neutron irradiation within e reactoth r change e numbeth sd distributio an r dislocae th f o n - e structurationth n i s l materials, without changin e graith g n structure. This phenomeno materialf o mad e e b us en ca ns science research, and we are planning to use the research reactor in fu- greatea tur o t e r exten r thifo ts purpose.

154 NEUTRON PHYSICS

. BALASKÖM . CSERL , . ROSTAL , . SVÄE , B Central Research Institut r Physicsfo e , Budapest, Hungary

Abstract

a serie Onf o ef seveo s n papers describin e activitieth g e th f o s Hungarian VVKSZ-M typ 5 Me W reacto e presentedar r e reactoTh . s i locater t a d the Central Research Institute for Physics. The activities include 1) Production of isotopes, 2) Application of reactor-produced radionuclides for industria d environmentaan l l investigations ) Nuclea3 , r structure studies using fast neutron for (n, n'y) reactions, 4) Reactor neutron activation analysis, 5) Hot atom chemistry, 6) Testing of structural materials, and 7) Neutron physics. These series of papers present a very comprehensive summary of the reactor activities.

All over the world interest is increasing in non-destructive material testing. Wite hel th f hnon-destructiv o p e methode th s micro and macro structural details of an object or the result of a technological procese testeb n dca s without demagin e objecth g t or making it unsuitable for farther use.

Neutron radiography, base n transparenco d y - propertieob e th f o s ject versus neutron radiation is an advanced technique in this fielneutrod an d n scattering techniques like neutron diffraction or small angle neutron scattering are also widely used for the microstructure stud f materialso y .

Using thermal neutrons obtained from the WWR-SM reactor of the CRIP we have built spectrometers for neutron radiography, neutron diffractio smald an n l angle neutron scattering investigations, respectively maie Th n. characteristic e spectrometerth f o s d an s our activity in this field are as follows.

NEUTRON RADIOGRAPHY

The schematic arrangemen e equipmenth f o t s i showt e n Fig.i nTh . 2 neutro e nobjec th flu t a xt positio 0 n/c1 ms i n sec scintilA . - 8 2 lato lighw lo r tscreea leved camerV an nT l a with video output are used to detect the neutron radiography image of the investi- gated object resolutioe Th . s i aboun urn 0 n additio20 I .t e th o t n

155 Scintillator screen Shielding tube

Neutron beam .Mirror

Object © © ^^s / o recorder / Monitor /

Low light level TV camera

Fig. 2. Schematic arrangeaient of the dynamic neutron radiography experimental installation

neutron radiography image some physical parameters (e.g. tempera- ture, measuring time, pressure e investigateth f o ) d objece b y tma visualized on the monitor and recorded on the same video tape for farther evaluation.

e investigationTh e focusee observatioar sth n o d medium-speef o n d motions of hydrogen containing fluids in metal tubes. The most important application e followingth e ar s .

e workinTh g processe f absorptioso n type refrigarators wer- in e vestigated e higTh . h hydrogen contenworkine th f o tg fluid enables to visualize the process of boiling and transfer in the bubble pump withi e double-walleth n d pipe e condensatio.Th f ammonio n a e condensatorth n i s ga e formatio,th e evaporatiof dropo th n n i s n measuree e leveb syste th e tann f fluith o ld ca k n an mdi d with high accuracy y inaccurac.An e relativth n i y e positioe th f o n coaxial tubes and dirty spots in the system become clearly vis- ible. Neutron radiography investigations give possibilita s f o y optimalizing power and of increasing efficiency.

Neutron radiograph s use o studwa y t d e inne th y r processe f heao s t pipes, whic e increasinglar h y popular device f preseno s y heatda t - ing technology e circulatioTh . workine th f o ng fluid (e.g. water, sodium) suc boilings a h , condensatio d leadinan n e g th bac f o k

156 condensate were visualized s observewa t I . d thagreae th t t volume of gas bubbles created during boiling pulsing flow of the fluid which, in turn, causes a periodic drying of the inner surface of e heateth d pipe. This t beephenomenoye n t describeno s nha d an d will be a very important consideration for engineers planning heat pipes.

Some farther applications: the circulation pump system of a streem cromatograph; line of some feeding valves; the process of injec- tion moulding during only a few seconds has been visualized.

SMALL ANGLE NEUTRON SCATTERING (SANS)

The schematic arrangement of our double crystal SANS device is e singlG o bases tw ei n crystalt o dI show . 2 n Fig. i nf 0.6 o s ' mosaic spread arranged in focusing geometry. The sample is placed between the two crystals, and by detector D, is measured the rock-

ing 0 analysecurvGe f o e r crystal, whil 9 detectoeD r measuree th s £ £ integrated intensity scattered on the sample. The momentum region of s scanne0-0.e spectrometeri th y 1R b d .

Reactor channel

Coltimator

Monochromster cryst

Sample

x \ Ge?Analysercryst

detecto, D, r

, detector

Fig. 2. Schematic view of double-crystal SANS device

157 This metho s use o investigatwa dt d e effecth e f deformatioo t d an n brokening of steel samples. In the deformed sample an increased SANS intensity was found with respect to the normal sample. For the broken sampl e SANth eS intensit s stilwa y l larger.

The effect of running time on the SANS intensity was measured on air craft turbine blades - the results are shown in Fig. S. The slope of measured curves could be fitted by a linear plot for blades of very short running time (-40 h) while for blades of longer running time (~4OO h) this function was found to be convex.

Informatio s obtaine e domaiwa n th n no d structur f metallio e c glass- e averagTh . es e domain size calculated froe broadeninth m e th f o g rocking curve i.e, s abouym i s .0 comparabl2 t e wite ribboth h n width.

VIEW OF TURBINE BLADE

______I___j __

~ 7 h 0 Typ4 A e > 6 Type A 392 h K

z 5 Type B 40 h LU Type B 448 h Q 2 i LU 3 O LU I- 1

l(cm)

Fig. 3. The A integrated intensity parameter measured at different points of various types of blades and of different running time

158 Another small angle apparatus is used to scan the momentum region of 0.01-0.1 A liqui . ~ 3dR nitrogen cooled Be-filter combined with pyrolitic graphite monochromator provides a neutron beam of average wavelength 4.3 A. The flux of the neutron beam is 4OO n/cm sec e samplath t e position e distanc.Th e betwee- e samplde th nd an e metersx x meterstectosi si s s i i r .A . A He-ga He-ga, sfi s filled cylindrical shaped detector consisting of eight rings is used.

Investigations of various biological macromolecules and micelles are in progress. The structure of sodium-dodecyl-sulphate micelles were investigated e temperatur.Th concentratiod ean n dependence of the average aggragation number was determined. The data were explained in the framework of a simple pair-correlation model; the aggregation number depende concentratioth n o s a fourth y b n - powe w ovelo rr wide concentratio d temperaturan n s ei ranget i s a s shown Fig. 4.

b.

0 0.1 0.2 c.c.SDS(M) Fig. Values4. fourthof averageddegreethe of aggrega- tion number versus SDS concentration at two tem- peratures: a/ 25 oC; b/ 60 °C

NEUTRON DIFFRACTION

A two-axis neutron diffractomete uses i rmeasuro t d e scatterth e - ing spectr0.4-1e th n 0i aA momentum range monochromatie Th . c neutron flux at the sample position is 1O 5 n/cm2 sec.

The structural ordering of Fe-Co alloys were investigated in de- pendence of heat treatment and of substitutional element like Cr, V, W. Connection was established between the atomic order and mechanical properties.

159 ATOMIC DISTANCE '[A]

. Structure5 Fig. factor f (NiQc-Fe35)??B23o metallic glass and its pair correlation function with oarious upper limit of truncation in S(Q) dem- onstrating increasingthe resolution r-spacein

160 The structure of fast-cooled liquid crystals, have been studied. e phasTh e diagram e solith df o smodification f MBBd EBBo s an AA have been established multimode th , e polymorphis s decribedwa m .

The local structure of metallic glasses with the composition of Ni-Nb, Fe-B, Ni-B, Fe-Ni-B were investigated. Using isotope sub- stitution sample partiae th s l atomic pair-correlation functions were determined o achievT . higa e h resolutio e calculateth n i n d radial density distribution function, our measured data were com- plemente y thosb d e obtaine e time-of-flighth t a d t diffractometer e "FAKELatth " electron accelerato Moscon i r w Atomic Energ- In y stitute. The results are illustrated in Fig. 5.

161 EDUCATIONA RESEARCD LAN H ACTIVITIES NUCLEAE TH F O R TRAINING REACTOR OF THE TECHNICAL UNIVERSITY BUDAPEST

G. CSOM . LEVAIF , . KEÖMLEG , Y Nuclear Training Reactor of the Technical University of Budapest, Budapest, Hungary

Abstract

Simultaneously wit e e spreapeacefuth hth f o d l use f atomio s c energy in Hungary, the need for training specialists in this field also at universitie se middl aroseth f n sixtieso I decides e . wa t i d, thaa t nuclear reactopowew lo rf o rshoul e establisheb d e Technicath t a d l University Budapest r educationafo ,l al firs f o tl purposes reactoe Th . r went first critical in May 1971.

e paperth n I , after briefly surveyin e mosth g t important technical parameters of the reactor, having a maximum thermal power of 100 kW, our educational and research activities are summarized.

. 1 INTRODUCTION

With the spreading of nuclear power generation, and nuclear engineering in general, the need has arisen for trainin e nucleath n i g r fiel n Hungaryi d .

Takin e demandth g s into account e yearth n si , 1960-61 e Nationath l Atomic Energy Commission place n ordea d - rwit h e purposth f ensurino e g up-to-date condition r traininfo s g and research wor t universita k y leveo determint - l e th e characteristic data of a university reactor and to elaborate s studit y plans. This study plas beeha ne n Centra th don y b e l Research Institute for Physics of the Hungarian Academy of Sciences in colaboration with the Power Station and Network Engineerin Hungaryo C g e constructioTh . n work bega n i 196n 7 e anreactoth d r went first critica n Juni l e 1971 Centrae .Th l Research Institut r Physicfo e s designe build e corean d th t , control system, and the pneumatic transfer system. The Isotope Institut e Hungariath f o e n Academ f Scienceo y s designed an d constructee wastth t celd eho an lwate e th d r treatment systen.

163 As an independent institution, the Nuclear Training Reactor is subordinated to the Rector of the Technical University Budapest. The staff of the Nuclear Training Reactor includes about 50 persons, among them 20 research workers.

2. DESCRIPTION OF THE REACTOR

The reactor is a water moderated and cooled pool type arranged system. The vertical section can be seen on Fig.l. e cor Th s locate e bottoi en aluminiu a th f n o i md m s vessei d an l shielde y e topconcretb y wateth b s sided. it d t a ran t s a e e horizontaTh l sectioe seeb n Fig.2o n ca n , e showinth l al g horizontal beam tubes. Eacs differenha h t connections e coreth .o t

The map of the active core can be seen on Fig.3.

e maiTh n important parameter e reactorth f o s : VIk 0 10 Thermal power Fuel U0_, 10 % enrichment, 4x4 bundle arrangement Fuel pin diameter 7 mm active m lengtm 0 50 h cladding aluminium Critical mass 274 0U-235g , 9 pins36 , Fuel content 2952 g U-235 Moderator and coolant de-ionized water Reflector water + graphite Cold clean excess reactivity 165.3 cents "1 /" _ "~) _ "1 Peak thermal flux 2,7.10 neutron.s . m Experimental facilities 5 horizontal beam tubes 1 tunnel 19 manually loaded irradiation positions 3 irradiation positions connected with pneumatic transfer system

164 R-ZV70_

Fig. 1 . LONGITUDIONAL SECTIOE REACTOTH F O N R BLOCK 1-Reoctor lonk , 2-Graphite reflector elements; 3- Fuel element assemblies; t-Safety and control rods; 5-Detector tubes - Zon6 ; e tank - Zon 7 ;e holder mantlei fl-Diffusor - Injector 9 - jDivisio 10 s) n chamber, 11-Cooling water Inlet pipeline, 12-Zone holder ribs; 13 - Draining pipeline; K - Cooling water outlet pipeline; 15-Filling pipeline for the water trap of horizontal channel) 16-Tunnel and pipeline for leakage water; 17-Protecting cylinder; 1 8- Perforate d plate - Irradiatio9 1 , n tunnel 0 Wate2 , r tanf o k irradiation tunnel; 21-Vertical channel f Irradiatioo s n tunnel - Heavy-concret 2 2 , e radiation (biological) Shield - Norma 3 2 ; l -concrete radiation shield - Radiatio24 ; n shielding girtd columnsan h ; 25-Heavy concrete shielding - Heavy-concretdoor 6 2 ; e protecting plugs - Vertica7 2 , l irradiation channels 24-Supports of vertical irradiation channels; 29 - Support ing bridge for control rods,- 30 Centering and radiation shielding wedges ; 31-Reactor flat top caver; 32 - Reactor double cover, 33 Plexiglass bell-cover - Servomechanism 4 3 ^ f controo sd safetan l y rods; 35-Cable duct 6 Packing-glan3 ; d bushings; 37-Suctio r duct- Reacto ai n8 3 railingp ; to - r .

165 Fig. 2

CROSS-SECTIO E REACTOTH F O N R BLOCK

1- Fue l assemblies - Graphit 2 , ? element ( reflectoro s - Zon3 ; e lank 4 ,Zon e supporting mantle, 5-Detector tubes; 6- Basket for temporary (uel stroragej 7 Cooling water outlet pipeline; fl-Water r tanirradiatio(o k n channel - Irradiatio9 ; n tunne; l 10-Railway., 11- Heavy concrete shielding door; 12-Reactor tank; 13 - Protecting cylinder/ li - Horizontal channel protecting tube; 15-Water trap (or horizontal channel; 16-Protecting tube; 17-Steel protecting disc; 18- Valve box; 19 - Radiation shielding ribs; 20-Heavy concrete - Norma21 , l concrete - Radia22 / l horizontal channel I I 111d . IV.I an s. ;

23 - Tangent lonai horizontal channel V.j 24- Hot cell maintenance space. 1

166 (Dl) O

H A G B F E D III „ _ r1 ] V V 2]] V 3, V" 3 \ V.

o o oooo oooo oooo oo o o 0 OO oooo oooo oo o o oooo -ty 0 0 OO 0 000 oooo o^J o •0- ^\ oooo 000°^S°ooo oooo ooo o k 3 oo oo o o OßVrV 000 oooo oooo AUT(D6) \ oo oo oooo oooo OOOO oooo oo oo oooo oooo oooo O O o O ^ O oooo o o o o & oooo 0°°% II 1 oooo OOOO oooo oooo oooo oooo /0°°ooo0o oooo JOOlJ oo oo 0 OOD O O O D o o o o oooo tei 000^ 000 A 11 2 00 OO 000^Voooo -QO O O oooo oooo o ooo oooo oooo oooo oooo oooo ooo o oooo ^?- PER(D3) oooo 0 OO 0 o ooo ooo o OO O O 81

oooo o oo o oooo 0 O- OO o o o o o ooo oooo oooo O oooo o ooo oo oo OOOO oooo oooo oooo oooo S9; 82,JG; og — - - - — — - — — — —- — „ L v~K_

Irradiation tunnel

Fuel bundle fä\ Manuad ro l (ft) Control rod Graphite -g^ Safety rod TTT Air-graphite [QQ| Pneumatic transfer system Hole in graphite Q Manually loaded irradiation chann

Water Detector Neutron source

. ActivFi3 g. e core.

167 3. EDUCATIONAL AGIIVITY OF THE NUCLEAR TRAIXI\G REACTOR

In Hungary, the Technical University Budapest is the only institution for higher education having a nuclear training research reactor. It is, therefore, quite obvious that the Nuclear Training Reactor is available also for other Hungarian universities and colleges, the educational progranme of which includes nuclear power engineering, nuclear technology, nuclear physics and radiochemistry. Thus, in addition to the students of Faculties ^echanical Engineering, Chemical Engineerin e Technicath f o g l University Budapest, students come also from the universities of the country to atten e laboratorth d y exercise d lecturean s e s th hel t a d Mjclear Training Reactor r wide-ranginOu . g activite b n ca y best characterize e facth ty b thad e havw t a close e contact un the field of education with 30 departments of 11 universities and colleges of the country.

In an educational point of view, the Nuclear Training Reacto s attractivi r e also internationally: measurement exercises have been recurrently organized for university students from Zittau /German Democratic Republic/, Prague, Bratislava, Moscow, Algier and Havana.

So far we have had three-times the opportunity to organize interregional training courses upon reques f I7iEAo t : in 1979 /4 weeks/ : with the title Interregional Training Cours f Researco n e trio eUs e h Reactors; in 198 3weeks6 1 Interregiona: / l Trainine Us g e Coursth n o e f Researco h Reactors; in 198 months43 / Interregiona: / l Training Cours n Researco e h Reactor Operation

The following basic considerations were decisivr fo e the organization of the courses /as form lated by Messrs.R. Muranaka and J. Dolnicar, IAEA Scientific Secretaries and y us/b :

168 Citation : "1. Ther e numerouar e s research reactor e developinth n i s g Member States which are not fully utilized. The reason is frequently the shortage of trained personnel.

2. In the near future, a number of new research reactors will become operational. The staff of these reactors need guidanc d trainin an e utilizatio th n i g f theio n r research facilities. e improvemen3Th . e measurinth f o t g techniques,the rapid introduction of computer-based data acquisition systems and on-line experiment controllers brin w aspectne g n i s research reactor studies. Similarly, the new methods of radioisotope production, permittin e manufacturth g f o e useful amounts of radioisotopes, even using a relatively low-flux reactor ,e opportunitie openth p u s r smalfo s l reactor centres. Thes w techniquene e s mus e studieb t d and learnt.

4. The specialization of engineers and scientists has grown to an extent that it has become a hindrance for the efficient work in a research reactor cnetre which is,by its set-up, usually a multidisciplinary institution. Therefore, it is usefu e reacto th o hav t lt a er centre personnee ar o lwh familiar with the different aspects of research reactor operatio d usean n . Such persons coul e efficientlb d y trained in the Agency's courses."

The above arguments were carefully considered in preparation for the courses and a programme was arranged to best comply with the requirements which the trained staff in research reactor laboratories should meet.

The educational activity of the Nuclear Training Reacto s concentratei r n laboratoro d y exercises, attended by 2 to 5 students for 4 to 7 hours.

169 e studentth r f Fo differeno s t progressio d fielan n d of interest measurement exercises are held in the fields of Reactor Physics, Reactor Operation, Radiation Protection, Nuclear Measuring Technique, Reactor Neutron Activation Analysis.

e necessarAlth l y facilitie r sucfo sh exercisee ar s provided for the Nuclear Training Reactor.Such facilities are - nuclear reactor, - vertical and horizontal irradiation channels, - pneumatic transfer system, - hot cell, - radiochemical laboratories with adequate equipment, - small computers, - multi-channel analyzers, - Nal/T d Ge/Lian L , HPGe detectors, - various nuclear measuring instruments.

Consultations with d assitancan , student, to e s working in the so called students7 scientific teams as well as students facing final examination and postgraduates preparing their thesi e considerear s e mosth dt effectiv er educationapoinou n i t l activity. These students or postgraduates spend months or sometimes years in the laboratories of the reactor and their work is a valuable contribution to the results of research a givewor n i kn field.

Several compulsory and/or facultative special courses e senio th e hel y ar b rd research worker e institutth f o s n i e the field of Reactor Physics, Radiation Protection, Neutron Activation Analysis.

In additio o normat n l educatio t differena n t universities and colleges, the Nuclear Training Reactor takes its share in the universities' postgraduat d othean e r coursesr Ou . contributio e theoreticath o t n d practicaan l l educatiof o n the specialists of the first Hungarian nuclear power plant in Paks is also important.

170 e NucleaTh r Training Reactor organizes training courses including theoretical and practical education for the specialists of the Paks Nuclear Power Plant. Courses like these were held for the operators of the power plant e specialistth r ane fieldfo dth f f radiochemistryo o s , radiation protection and material testing.

The Nuclear Training Reactor provides the possibility for the specialists of the Nuclear Power Plant for refreshing their knowledge. This case they spend a few weeks or months here and have the opportunity to join the R&D works pursued by the institute or any other activity which is beneficial e powefoth r r plant.

e expertth Man f o ys froe poweth m r plant take part at university postgradual courses regulary organizey b d the Nuclear Training Reacto a fou r r fo rsemesters ' duration.

Otherwis e wanew o emphasist e thae educationath t l forms provide e Nucleath y b dr Training e Reactoth r fo r specialists of the power plant are basical, theoretical and so do not substitute the concrete power plant and simulator exercises. These exercise e hel t Novovoronezhar sa d e Th . power plant simulator planned to be built at Paks will be also a great help.

4. RESEARCH ACTIVITY OF THE NUCLEAR TRAINING REACTOR

The following principle has been taken as a basis when elaborating the research programme of the Nuclear Training Reactor: - The Nuclear Training Reactor has been designed primarily for a high-level up-to-date education of specialists. Research shall adapt itself to the current problems, providin e samth et a gtim n intellectuaa e l background for education while keeping pace with the recent international results. Like other institutions for education, the Nuclear Training Reactor can expend its

171 intellectua d financiaan l l capacit n researco y h serving particular social and economical purposes only after all the aducational requirements have been met.

According to decisions based on the mentioned principle, the activity of the staff of the institution has been concentrated on the following main problems:

4.1. INVESTIGATION OF THE NUCLEAR FUEL CYCLE

Studies of more general problems in the field of nuclear energetics in addition to problems closely related to the training reactor are justified by the national energetic interest e activitieth y b wels a ss a l s withi a systen f o m international co-operation affecting also the nuclear energy programme of Hungary considerably. However, studies of the nuclear fuel cycle involve rather theoretical analysis than practical experiment e reactorth n i s . Therefor e refew e o t r the the literature instead of a detailed exposition.

4.2. INVESTIGATION OF NEUTRON AND GAMMA RADIATION FIELDS

Ever since existing, our institute has been engaged in theoretical studies and experimentation of the biological shield around complex radiation sources, like a nuclear reactor. The most important problems in this field were to elaborate, and adapt computer programmes for shielding calculation o confirt d an sm these programmes experimentally, o investigatt e shieldinth e g propertie f differeno s t shielding material d configuratioan s f engineerino n g structures e shieldingith n o investigatt d an , e activatioth e f o n materials in neutron radiation fields /such as structural materials, shielding materials/ as well as the effect of activatio e operatioth n o nd shutdow an n f nuclearo n reactors.All these activitie e closelar s y relatee th o t d constructio d preoperationaan n le firsworkth tf o s Hungarian nuclear power plan n Paksi t .

172 More recently, these activities have swung towards neutron spectrometry and applications in this field. Singificant results have been achieve e developmenth n i d t of complementary methods of neutron spectrometry /using multifoil activation, protonrecoil based gas filled and scintillation counter, semiconductor detector/, permitting comprehensive measurements through the entire neutron spectrum /O to 12 MeV/ of the reactor. The results are used in neutron dosjjnetry /in mixed radiation fields/ and in researc n damageo h f structurao s l material e coursth n i es n internationaa f o l comparative study controlle y IAEb d A where our Institute represents one of the three basis institutes. All these activities are closely related to the problems of nuclear energetics, first of all to those arisine Pakth s n i Nucleag r Power Plant.

4.3. RESEARCH AKD DEVELOPMENT IN THE FIELD OF NUCLEAR INSTRUMENTS AND METHODS

This programme is also dictated by the country's nuclear energy programme. The objective is to develop nuclear measuring devices which are, owing to the reduced demand, commercially unavailable, but their -use is vital in respect of reliable operation of the nuclear power plant.

Essentially, ther e threar e e r developr^npointou n i s t activity whic e wortar hmentiono t h .

- A boric acid concentration meter was developed by our staff. This device can be built into one of the branch pipes of the primary coolant circuit, and its principle of operation is neutron absorption of B isotopes.

- The activity of the fission product noble gases emitted by the nuclear power plant can be measured selectively and continuousl a HPG y eb y based instrument built inte th o air chimnee plantth e measurinf Th o y. g devicen i s i s operation at present.

173 - Neutron radiography is used to investigate fuel rods and other nuclear materials. An equipment suited to produce thermal neutron radiograms has been developed at the horizontal channee Traininth f o l g Reactor n apparatua w No . s e productiosuiteth r fo d f up-to-dato n e sectional images has been developed, designe r testinfo d f bundleo g f fueo s l elements and, in combination with hard garnira radiation, testing of welded joints as an industrial application. e projecTh f sectioo t n imagin f reactoo g r fuel bundls wa e partially sponsored by IAEA.

4.4. DESTRUCTIVE AND NON-DESTRUCTIVE NUCLEAR MATERIAL TESTING METHODS

This field of research includes essentially two issues sucs a h - activation analysis, - developmen f radioanalyticao t l system f nucleao s r power plants.

Within activation analysis, reactor neutron activation analysis shoul mentionee b d n firsi d t place s seeA . n earlier researc n thii h s fiel s feasiblei d , although limite ar s obviousl o feasibilitt t relativele se y eh y b y w reactolo y r power. Therefore, like otheth e r radiochemical laboratories of the country, we irradiate several samples in the reactor of the Central Research Institute of Physics the power of whic s witi hn ordea h f magnitudo r e higher. However, for isotopes of shorter half life we use our own reactor.

e coursIth n f researco en initiativow n o h d undean e r contract, several matrices have been analyzed n doinI ., so g trace concentrations have been investigated in biological, archeological, environmental and metal samples.

Usin e methodth g f activatioo s n gamma-spectometry, we have recently joined in works concerning determination of fission products and radioactive corrosion products accumulating in the primary circuit of nuclear oower plants. The device

174 which has been built determine continuously tha radioactive components of the water in a by-pass of the primary circiut.

It is worth to mentLon our activity controlling the release through the stack of the power station of noble gases, 89 '9 0 Sr, radioionides and radioactive aerosols, by methods developed in our institute.

5. SUMMARY

In summin p educatiou g d researcan n h e workth n i s institute and the interactions between them, the following generalizable conclusions can be drawn: 1. Like in any small country, there is only one single nuc- lear reacto n Hungari r y designed essentiall r universitfo y y education d researcan , o bac t hp thi u k s education. Accord- ingly, the scope of this reactor is more comprehensive as compared with training reactors specialize r educatiofo d n in reactor physics, radiochemistry r radioanalysiso , e Th . nuclear reactor of the Technical University Budapest has to comply with diverse, sometimes inconsistent, requirements.

2. According to our experience the educational activity of the Nuclear Training Reactor fits well in the Hungarian university system d servean , s suitabl e postgraduath y l trainin e experte Pakth th s f f o go Nucleas r Power Plant. The institute plays an important role in respect of training and R&D in local nuclear energy programmes.

3. The scope of education necessitates that a number of special fields be represented by the training staff includin 0 persons2 g e jointh : t effort f physicistso s , chemists, geologists, electric engineer d mechanicaan s l engineer e requirear s o complt d y wite requirementsth h .

s 4followA . s froe requirementth m s imposee reactorth n o d , courses for groups of a larger number of students, in

175 addition to individual education, are predominant within the educational system, dissimilarl o othet y r institutes f thio s type.

5. There is a close interaction between research and educa- tion. Consequently, also the scope of R&D is wider than in case of training reactors designed for one special purpose.

6. Special requirement e thuar s s imposed upoe reactorth n , laboratories, and organization of education and research. E.g. it is not easy indeed either for the reactor or for the users to co-ordinate measurements requiring sub- critica le reacto stat th reactoa f r o e. o r kW r0 powe10 f o r

7. Experienc e recenth f o te years y encouragsa o t s u e that in an engineering point of view, the nuclear reactor and the laboratories and in respect of software, the staff of the institute are capable of coping with the problems. r smal fo r opinion Ie lou n us r f experienco ou , e b y ma e and developing countries, where the objective is to construct and operate a multi-purpose training reactor lik n Hungaryi eo pla t nd an educatio, d researcan n h base n trainino d g reactor.

REFERENCES

l~l_l "Papers froe Nucleath m r Training Reactor". Special e Periodicissuth f o e a Polytechnica, Electrical Engineering s 1-2,No Vol,, Page26 . s 1-213, 1982. Published by the Technical University Budapest, Hungar n English/i y /

176 RESEARCH REACTOR ACTIVITIES IN INDIA

C.L. THAPER Bhabha Atomic Research Centre, Trombay, Bombay, India

Abstract

researcx o tarS si , h reactor t differeno s t design d powean s r levels have bee ne Bhabh builth t a t Atomic Research Centre. e Asparth Thes 1 MW)e ( aar e , Ciru 0 MW)(4 s , Zerlina (negligible), Purnim I (negligible)a , PurnimI I a (negligible) d Dhruvan , a (100 MW) e Purnim. Th plutonius i I a m fueled while Purnim s fuelei I I ad with U-233 e utilizatioTh . t theso n e reactors i s described including design studie f smalo s l reactors, neutron beam research, radioisotope production, neutron activation analysis, reactor engineeringd an , education programmes.

Research reactor e generallar s y use n producini d g radioisotoped an s carrying out reactor engineering experiments. They are also powerful tools in conducting basic and applied research in several disciplines. x researcsi r ta h o S reactor t differeno s t design d witan s h different power levels have been built at Bhabha Atomic Research Centre (BARC), Trombay, These are Apsara, CIRUS, Zerlina, Purnima I, Purnima II and DHRUVA. Fig. 1 shows some ot the salient features ot these research reactors. Zerlin d Purniman a werI a e buil r specifito t c engineering experiment d havw beean sno e n decommissioned. Purnims provideha I I a a d lot of data on the design of small reactors to be used for neutron radiography and other purposes. The first of these reactors, Kamini will be located at the Reactor Research Centre, Kalpakkam. Apsara has been used tor neutron beam research, neutron activation analysis, isotope productiow reactofe a rd an engineerinn g experiments. CIRUSa , more powerful reactor, continues to be used for production of isotopes, neutron activation analysis, engineering loops experiments and neutron beam research tor the last 25 years. DHRUVA has been commissioned in August 1985 and its operation will considerably enhance the research activities in India. I shall briefly touch upon some ot the research activities (particularly neutron beam work.) carrie t wite Apsarou dth h a and CIRUS reactore rolth e d thaan s t DHRUVA reactor will pla n thesi y e activities.

177 Apsara Ciras * Zerlina * Purnima-I Purntma-II Dhruva

Type of Pool type Tank type Tank type Fast Solution Tank type reactor Fuel Enriched Natural Natural Plutonium Uraniu 3 Naturam23 l uranium uranium uranium ssuranyl uranium nitrate

Moderator Light water Heavy water Heavy water None Light waler Heavy waler

Coolant Light water Light water Heavy water Air Light water Heavy water

Power level 1MW 40 MW Negligible Negligible NegligiblW M 0 10 e

Maximum 125xl013 67x10" — — — 13x10" neutron flux

Date of Aug '56 July '60 Jan 6J Vdy 72 May 84 criticabty • Zôrlin s decommissioneawa 198dm 3 conversio Purrumf no pumuno i mi Made dI wa I aI 197n Ji 6

FIG 1 Feature. f researcso h reactors.

2. Utilizatio t Researco n h Reactors

1 2. Neutron Beam Research

Neutron beam research has been one of the raison d'etre of the thermal research reactor t Trombaya s . Neutron experimentr fo s investigating the condensed state of matter were started soon after Apsara began operation and the programme gained momentum with the commissionin e earlt CIRUo th g n yi S sixties.

A variet f instrumento y s suc s singla h e crystal dittractometer, powder ditfractometer, polarized neutron dittractometer, filter-detector spectrometer, triple-axis spectrometer and rotating crystal spectrometer have been designed and built over the years and these have been exploite o investigatt d e several problem neutron i s n crystallography, magnetic diffractio d spian n n density distributions, Lattice dynamics and molecular motion d reorientationan s n specialli s y chosen systems.

In neutron crystallography stud f structuro y f biologicallo e y important molecules like aminoacids, nucleotides, bipeptided an s investigatio f naturo n f hydrogeo e n bon n varioui d s systems were somf o e

178 the aspects covered by the Trombay group for several years. Recently stud f f phaso o y e transition othen n othi i s < r systems like LiKSs beee ha on On e subjecth f o f investigationso t .

The magnetic structure studies of several ferrites, mixed ferrites, Heusler alloys, etc. carrie t earlie e ou determinatiod th o rt havd le e n f magnetio c structure d spian s n density distributio a ver f yo n large numbe f systemso r n recenI . t years emphasi s shifteha s o dilutt d e magnetic systems and systems like NiRu alloy wherein small variation in concentratio f constituento n s result n fairli s y large variationn i s magnetic density distributions.

n inelastiI c scattering several investigations have been carriet ou d e librationaith n l motion f mano s y ammonium salt d crystaan s l hydrates and phonon dispersion curve n severai s l simple systems n recenI . t years librational motions in several aminoacids and phonons in more complex systems like X-KNO and inelastic scattering from a mineral-stibnite (Sb S ) have been carried out. Measurement of magnon dispersion curves have also been done in some magnetic systems.

Quasielastic scatterin f neutrono g s have also beena carrien i t ou d w liquidsfe , molecular solid d paramagnetian s c systems n liquidI . s like CH , CD and NH these have provided information on the rotational motions. Reorientational motions in several pure ammonium salts and mixed ammonium salts have yielded valuable information not only on the e characteristith rat f o e c motion t alsbu s o identifie e geometrth d f o y the randomly moving molecules.

In addition to the judicious choice of the problems and instruments emphasis has been laid on the development of new techniques and methods to overcome the limitations imposed by the medium flux at CIRUS. A novel high resolution instrument calle e AT-windoth d w spectrometer using a combination of beryllium blocks kept at two different temperatures serving as energy analyzer has been designed, built and tested at BARC and this is operating at the Spallation neutron source at Rutherford Appleton Laboratory, U.K.

The operation of DHRUVA will give further impetus to the neutron beam researc t onle higheno th ys n Indiai i h rt I neutro. n flut a x

179 oo o

SMALL ANGLE 4-ClRCLE NEUTRON SPECTROMETER SPECTROMETER CX FFRACTO METER NEUTRON M>GH PBfOSCM STRUCTlPf STÜCKES CF BKJlßOCM. f, TEFEST,

TWPVEAX3S SPECTROMETER FILTER OCTECTOB PH&IOHS, MAGHONS, SPECTROMETER PHASl MOLECUUt* MB**«»«,

PROPIE A*i*tVS8 SPECTROMETER OrTUSESCATTERWS I RESOLUTIOHO N SPECTROMETER TRIPLE AXIS ROTA P.NG CRYSTAL XAO SPECTROMETER PHASE TKAHSlTlONS /w sot /os HIGH f>£SCLUrXM LOW EHEffGY PWOMXS sruciesûf BfKlHCXHIHGUN£ fANXIM MOTIONS

lfCUlA» SOUDS. QUASI ELASTIC SPECTROMETER S roOAJTT r/cwo C« s ff* *«

ANOMALOUS SCATTERJN6 HIQH-0 WFFRACTOMETER

REACTOR HALL

FIG . Schemati2 . c vie f experimentawo l facilitie t Dhruvasa . DHRUVA, but special features incorporated for tailoring the neutron beam, more sophisticated instrument d controlan s d bettean s r data collection, acquisitio d processinan n g systems which will enhance th e effectiveness of the neutron beam research programme and also allow us o undertakt w typene ef investigationo s s whic e coulw ht undertakno d e earlier. Fig. 2 shows a schematic view of the experimental facilities for neutron beam research which are planned for this reactor. Some of the applications of these instruments for investigations of condensed state of matter are also included in this figure.

These applications envisage structural studies of systems up to 100 atom r unipe s t celd phasan l e transition a functio s a s f temperaturo n e and pressure. Study of phase transitions in magnetic and non-magnetic systems would be a major activity via magnetic diffraction as well as inelastic neutron scattering studies. Soft mode spectroscopy, study of anharmonic effects in semi-rigid solids and high resolution quasielastic scattering will be of interest using the inelastic and quasielastic scattering spectrometers at DHRUVA. Topography and small angle scattering studies from metallurgica d biologicaan l l materials wile b l w areane e s th whersom f o e wilw e l tak p investigationsu e . Magnetic and nonmagnetic defects will be studied through diffuse scattering and dynamical diffractio d scatterinan n g amplitude y neutrob s n interferometry.

The hot source would help in carrying out investigations in chemical spectroscopy, phase determination in crystallography and high-Q diffraction from amorphous material d liquian s d e structuresth l al s A . spectrometers will be coupled to a fairly powerful computer via the microcomputer net work it should be possible to increase the quality and quantity of the throughput.

Neutron beam researc n appliei h d areas like neutron radiographd an y texture studies has been carried out with these reactors. Several investigations on the understanding of nuclear fission have also been done.

181 2.2 Radioisotope production

In India Apsara and CIRUS reactors have been extensively used for isotope productio r varioufo n s application e areath f nuclean o si s r medicine, industry, agriculture and research. This has been an on-going activity since o mee19bT e nee th f 8tvariou. o d s application a largs e numbe f isotopeo r e beinar s g produce a regula n o d r basis. Som f theso e e are MO-99, Cr-51, Hg-203, 1-131. Co-60, Ir-192, Hg-197, Sr-8b, Tl-204, P-32, S-3b, Ca-4b. etc e tota.Th l activit t variouo y s isotopes annually produced in these reactors is about bO.OOO curies. For various applications isotope products are made and supplied in various forms. Thes e mad ar weln ei e l equipped laboratories buil n thii t s Centre.

Wite operatioth h f DHRUVo n A reactor, BARC will hav a considerable y enhanced isotope production capability and will also take up production ot such isotopes as tritium, Carbon-14 and Iodine-125, which are needed in many applications.

2.3 Neutron Activation Analysis

One ot the important uses of research reactors has been their utility as a source of neutrons for activation analysis. Studies in activation analysis using reactor neutrons have been pursue n Indii d a using Apsar d CIRUan a S reactor d thesan s e will gain further impetus with

e operatioth f DHRUVAo n e sensitivitTh . d selectivitan y f dato y a have considerably improved wite availabilitth h f higheo y r flud higan x h efficiency-high resolution detectors with associated instrumentatiod an n radio-chemical separation. The methodology employed has been to carry out time dependent measurements and to measure more than one x-ray wherever feasible. Neutron activation analysis has been applied to problems in material science, earth sciences, forensic science, environmental and life sciences and archeology. Emphasis has been laid to use neutron activation analysis for providing validation support programmes using other analytical techniques. There is a merit in exploiting radiations and particles emitted promptly in addition to analyzin e radiatioth g n emitted from activated species. These ar e extremely useful and there are plans to embark on this programme in the near future.

182 4 Reacto2. r Engineering

The experience gained in designing, building, operating and maintaining the research reactors at Trombay has been of significant help in developing overall competence and expertise required for designing and building DHRUVA reactor and running nuclear power reactors e countryith n . Valuable reactor physic d reactoan s r engineering data have emanated from these research reactors. In particular CIRUS has been user tesfo d t irradiatio f nucleao n r fuel d othean s r materiald an s for training personnel to operate the power reactors. Two in-pile loops designed for test irradiation of fuel assemblies and other materials at DHRUV Af significano wil e b l t value.

5 Educatio2. n Programmes

BARC has been running a Training School since 1957 in which 150-200 scientists and engineers are selected for a one year training course. A major input to manpower requirement of research and power reactor and other programmes of the Department of Atomic Energy is met through these trainees. Special long and short courses are regularly or periodically conducted by this Centre for training students, technologists and scientists in the use and handling of radiation sources for industrial and medical applications. Student d teacheran s s from universitied an s visitors from abroad periodically come to this Centre to pursue training and research with neutron beam.

6 2. Summary

The experience of over 25 years in building and operating research reactors in India has provided trained manpower and competence to design, build and operate power reactors and more powerful research f reactoo reactorse a scientifius r o e t neutront Th onld .no le ys c ha s culture but also led to isotope production for use in nuclear medicine, industry, agriculture and research; neutron beam research to investigate condensed state ot matter and neutron activation analysis as an analytical tool tor several applications.

183 RESEARCH REACTORS CONTRIBUTION IN NATIONAL NUCLEAR PROGRAMMES POLANN I D

J. KOZIEL Institute of Atomic Energy, Otwock-Swierk, Poland

Abstract The Polish Research Reactors EWA and MARIA are located in the Isotope Production and Reactor Centre/IPRC/ of the Institute of Atomic Energy.

EWA-10 MW s firs t ,wa intpu t o servic 2 Mn 195i Wea s Researca 8 h Reactor, designed especiall o isotopet y s irradiatio neutrod an n n beam experimentst I . s beeha n upgrade o timetw do t achievs e actual powe 0 MW1 r .

MARI 0 MWa materia3 s - Ai , l testing reactor with large capabilitf o y isotope irradiations. Some horizontal neutron beam tubes have been also designed.

Nuclear power programm n Polani e d demands research support. MARIa s i A particularly convenient reacto r loofo r p experiments o thalargo s , tw t e loops are being under construction. The first one, to light water, PWR type reactor e ansecono fasth t d s ti d breede s coolega r d reactor programme.

Neutron Beams of EWA and MARIA reactors are used to solid state investigation. For this reason several sort of neutron spectrometers and diffractometers have been designe d constructedan d .

Among different services, activation analysis and neutron doping of silicon are the most important.

The spent fuel of MARIA reactor is a convenient gamma radiation source s usei o sterilizt t dI e some medical equipment.

Suc a widh ee productiorangth e servicef o th e o d satisft an ns i e s th y national needs and is also the subject of an exportation.

INTRODUCTION

Two Polish Research Reactors, named the first EWA and the second MARIA are located in the Institute of Atomic Energy e t operateSwiera ar e Isotop d th an y kb d e Productiod an n Reactor Centre. The Institute of Atomic Energy is a continuator of the long time, more the a quarten a century f o r , experienc n radiai e - tion application of the former Institute of Nuclear Research,

185 DESCRIPTIO REACTORE TH P O N S

EWA is a light water moderated and cooled, enriched uranium fuel, tank type reactor, operateW K t presen a d0 1 n o t thermal power, vith maximal neutro 0 1 n/c n. flu5 m 1. .secx . 14 2 s firs It intwa t pu to servic ResearcV M 2 n 195 i ea hs 8 a Reac- tor purchase Soviee th n ti d Union. The fuel was 10% enriched uranium dioxide and magnesium cera- mics, clad with aluminium, 10 mm diameter pins. /1/ On this reactor, wit n averaga h e thermal neutron flu0 1 x o n/cm .sec, in the fifties, the nuclear programmes in Poland were initiated. o 1964t p U , durin e firs th x gyear si t f utilisatioo s e th f o n reactor, more then 300 papers and reports concerned the works connected directly with the reactor were published. The reactor was used for reseach in solide state, for nuclear and reactor physics studies, for chemical research, for isotope production r biologicaanfo d l irradiation. In the sixties the reactor was reconstructed. Increasing of the useful neutron flux was the task to perform. /2/ The upgranding of EWA reactor was performed successively in three steps:

1-s- powet . rM¥ increas4 o t p u e The doubling of the power and neutron flux has been realised by the simple Yenturi tube instalation for e coreth n .i e fuen th eacpi lf o h comple2-n- d x reconstructio d powean n. rMW increas8 o t p u e e fueTh l elements were exchanged. Multitube fuel assemblie # enrichmen36 f o s t have been applied instea f 10/o d 4 enriched pins. Beryllium reflector was added.

I86 w corThe specials testene eth wa e n o d y constructed critical assembly, used after thar studiefo t n reactoi s r physicd an s for training. In 1967 the reconstruction was finished with no significant interruption of service, and the reactor obtained the licence f thermato o W operatM l8 powern o e . In 1971, when the programme of measurements and analysis s finishedwa e reactoe licencth th , W t M o operat t go re0 1 n o e and with maximum thermal neutron flux 1.5 . 10 14- n/c/ m 2 .sec.

MARIA - the second Polish Research Reactor /3/, has been designed in Poland with the core based on the MR reactor pro- Soviee jecth f to t /4/e teson ,t reactors.

TABL. 1 E

GENERAL CHARACTERISTIC F MARISO A REACTOR

NOMINAL POWER 30 MW

Maximum thermal neutron flux: in fuel 2.5 • 10U n/cm2 sec in beryllium 4.7 n/cm2

Moderator water and beryllium

Reflector graphite /bloes in Al cams/ and water

Fuel element: material U-A1 alloyl A cla n i d enrichment 80 % U-235 shape Six concentric tubes overal dimesions D O height m c m c 0 7 10 ,

Primary fuel cooling system: type of fuel channel Field tube pressure range 0.8 - 1.7 MPd temperature, core inlet /ou-tlet/ 40/79 C water flow rate: per channel 30 m3/h total 600 - 700 in /h

Primary pool cooling system: présure atmospheric temperature at core matrix inlet 40°C at core matrix outlet 45°C water flow rate 1200 ni/h

187 MARIA is a water and beryllium moderated, water cooled reactor of pool type, with preaurised fuel channels containing concen- tric tube fuel elements of highly enriched uranium, clad in aluminium and it reached first criticality in 1974. A summary e reactooth f r parameter s givei s n Tabli n . 1 e The design power level of the reactor is 30 Mtf tough it has been assumad e increasethab e powe e futurth y t th ma r n i ed up to 66 Mtf. The power increasing can be desirable since the reactor cors largha e e dimension a sufficien t ge o t , t excess reactivit a significann cas i yf o e t numbe f loopo rd rigan s s is installed. e FielIth n d type channel e coolinth , g water flows downward e outeith n r annul d returnan i s s centraupwarit n i dl part. s velocit It e channeth n i yl reache 5 m/sec7. s . Inside th e first uranium tube, there is a 16 mm diameter filler with water, designe r irradiatiofo d e resonancth n i n e energy neutron n thermai d an sl neutrons. At the nominal coolant flow rate through the channe] i.e. 50 m /h and inlet water temperature kept constant 40 °C the permissible fuel channel powe reachey ma r s 244. 0kW The channel outlet water temperature should not exceed 110°C. The measured thermal neutron flux, in the middle of the core reaches the value of 3.5 . 10•4M n/cmO .sec. The neutron spec- trum is well moderated,/5/

ISOTOPE PRODUCTION

The production of radioisotopes was initiated first, with the sealed sources A reactor EW e sixtiese outse th n th i , f t o ta , . The production covered r thafo , t time, nearly completl e demanyth d of the country. The sources were used in all kind of gamma-ray relay d instrumentan s r varioufo s s measuremant s thicknessa s ,

188 TABLE 2.

SEALED SOURCES /examples/

No Isotope application Form of output Way to obtain Neutron flux Max . spec . e n/cse . m g / i C . v 1 1 fc l

1. Ni-63 s chromatographga y laye intn o r . cyl. sur. ^i-62/rx,T/Ni63 101« 5

13 2. Co-60 automatic s 4x6, 8x1000 mm cyl . Co-59/n,y/ Co-60 1.5-10 300

3. Yb-169 NOT 4x6 mm cyl . *Yb- 16 e/n,y/ Yb-169 3-10U 1200

i, . lr-192 NOT 4x5, 4x6 mm cyl. Ir-lgl/ri^/Ir-192 2.5- 10U 300

*• enriched target

density, liquid leve d manan l y others maie Th .n sealed sources produced than were: cobalt-60, selenium-75, silver-110, zink-65, thulium- 170, iridium-192, Of course, Co-60 source radiographr sfo d radioterpyan y were not praduced, however Ir-192, irradiate e wateth n ri dgap s o calles e formedth y beveb d l edge f controo s l fuel subassem- blies in the core, had sufficiently high activity to use them in the defectoscopy. The cylindrycal m diametelonm sourcem d m 2 gha 2 f d o san r an activity of 5.5 Ci. e e numbesealeTh th f o dr sources produce t thaa d t time amounted about 200yearr 0pe . An important part in the initial production of isotopes, repre- sented noncarrier solutio f iodine-131no , extracte meany b d s of wet method from irradiated tellurium dioxide /TeO^/. This isotope was the base for the production of 1-131 labelled organic compounds, suc s albumina h , bengal rose, hippuran. Nowadays, having two reactors and 25-years experience, the radioisotope production runs the gamout from the simple, mentioned above, to the pèsent day products as ytterbium- 169, iodine-125, RIA-kits.

189 TADL. 3 E

RADIOPHARMACEimCALS /examples/

No Labell.ag. /spec .act. Preparation Application max. Ci/g/

«* 1. Na-2/ /3 4 Sodium chloride 2. P-32 /10/ Sodium Phosphate 3. S-35 Sodium Sulfate 4. Cr-51 /300/ Sodium Chromate Chromium Chloride > medical ding-tosc t Albium Cr-51 5. Fe-59 /10/ Ferric Citrate 6. Cu-64 /10/ Cupnc Chloride 7. 1-125 /200/ Hippuran 8. / /3 1-131 Bengal Rose Tniodotyramine -s Iodine capsules medical terapy

GENERATOR SC1T1GRAPH1D AN S C KITS

1. Mo-99/Tc-99 M Pyrophosphate IO.&I Gluconate DTPA medical diagnostic Phitate EHDP DMSA Sn-113/ln 113M DTPA /O.I/ Phitate medical diagnostic Colloids

TABL. 4 E

RIA KITS /examples/

No kit denomination Labelling agent applications

1. T3 2. T4 3. ACT H

HG H iodine - 125 Radtoimmunologicsl Analysis 5. CE A

6. HCG Of, and ß

7. INS

8. AFP

190 One of the most applicated radioactive isotope in the modern nuclear medicine, espetial e tumoth n ryi diagnosi s technetium-99mi s , the doughter nuclid f molybdenum-99o e s i obtaine t I a . s a d fission product of uranium-235 or by the simple activation of molybdenum-98. Nowadays, the last way is exploited, The molybdenum-99 /half-life hours6 6 tim f n o fori e/ f mo molyMate absorbed into an aluminium oxyde column, forms a generator. Very applicable in biology and medicine in Poland is radio- iminunoessay n thiI . s branc e maith h n role play e radionuth s - clide of iodine-125, which is the labelling agent of the RIA-kite. It is obtained in a reactor on the way of irradiation of gaseous xenon. Xenon-124, one of the natural isotopes of xenon /about 0.1 %/, is activated to the xenon-125 and by the beta minus decay one obtains the iodine-125. The irradiation and the decay as well as the radiochemical processing of 1-125 is a tricky task, but the problem has been mastered. Finally, some words about the near future of the isotope production. Taking into account thae morth t e than half of the production is destined to the nuclear medicine, first to be developed are the medical isotopes. Carrier-free moly- bdenum-technetium production technology on the reactor is under elaboration. Another task to be accomplished is cobalt-60 strong source productio r radioterapfo n r gammfo d a an ysterilisatio n pro- gramme.

191 SUPPORT OF NUCLEAR POWER PROGRAMME

Nuclear power programm n Polani e d demand researca s h support. First Polish nuclear power station, being undir construction, will be turned-on to the grid in 1990. The next are designed. The programme is based on the WWER type reactor /Soviet variant of Pressurised Water Reactor/. Fast breeder reactors are also taken into account. MARIA reactor is particularly convenient for loop and rig experiments, so that two large loops are being under construction, The first one, for light water pressurised reactor, dynamic behavior study /LOGA invesigation/. The secon s purposei d r fasfo dt breede s coolega r d reactor investigation. The both programmes are carried out under a contract with the Soviet National Atomic Energy Commission. Some material testing in-pile experiments, on MARIA reactor have been carrie t yetou d . Two high pressure MPa6 1 , , with nitrogen tetroride rigs were irradiated. One of them in the central part of the core, the second on the margin. The irradiation was continued during several hundred hours. The structural stainless steel samples and neutron absorbing material were tested. Nowadayss mentionewa t i s d,a above dual-channela , , high présure, nitrogen tetroxide loo e constructedi p . GCFBR fuel pins are to be tested as well as several technological experi- carriee b o t ment de outar s / /? .

192 NEUTRON DIFFRAOTION

Neutron beams of EWA and MARIA are used to solid state inveetgation. For this reason several sor neutrof o t n spectrometerd an s diffractometers have been designe d constructedan d . The investigation of ferrite specimens improved by bismuth and manganese is made to order of POLFER, a factory of magnetic materials/ ./8 Eight horisontal m m bea 0 m10 channel d A reactoran EW m t m a s 0 ,6 diameter, and the thermal column are permanently used for research and testing ordered by the National Industry and mad meany b e f solido s e state physics methods. Inelastic neutron scatterin uses investigati go t d e MnFe^ ferrite d othean s r magnetic A reactoEW t a s r neutron spectro- meters. The investigation are also ordered by POLFER. /9/ Scientists from the Academy of Mines and Metallurgy in Krakov, neutroe th f o usin ne spectrometeron g A reactoEW t a s r beam tube test permanently textur f transformeo e r plate o ordet s r of Polish Ferrous Metallurgy. Those are some examples. -

TABL. 5 E ISOTOPL R INDUSTR FO SRESEARCD AN Y H /examples /

ISOTOPE OUTPUT FOR APPLICATIOND MAN S

Nd-24 S-35 Cu-64 unsealed soarces of radiation in different chemical forms Br-82 applie n hydrologyi d , pipelinT ND e Sr-90/0 Y9 chemical processing etc. La-UO Ir-192

193 SILICON DOPING

Six years ago, in 1979, at EVA reactor was initiated a service which is now some sort of nuclear production, being an important contribution in the development of the Polish electronic industry. It is the neutron transmutation doping of silicon single cristal ingots with phosphorus. In detail, it was presented last time on the Consultants' Meetin Silicon o g n Doping Transmutation Technique d Practicean s s hel n Poland i Internationae d th y ,b l Atomic Energy Agency. reactorA AEW t verticao tw , l rigs with special mechanical and electronic equipment have been designed and constructed for silicon neutron transmutation doping. Two inches of diameter maximum m 0 an35 dm length silicon ingot e movear s d vertically and turned during irradiatio avoio t ne dopin th d g ununiformity. The neutro nsilicoe measures i th flu g n xi ri n d continously e preseanth d t valu neutrof o e n fluence cause n interruptioa s n irradiatione th f o rige e locatereacto.e Th ar sth n i dr water reflector, where the average neutron flux is 8 . 101 *? n/cmn .sec. MARIA is also equiped with such a device. In the graphite reflector therverticaa s i e g destineri l r silicofo d n neutron transmutation doping. Accessible neutron flux is 2.1 . 10 o n/cm .sec and maximum permissible diamensions of the irradia- ted silicon ingots are: 3 inches in diameter and 500 mm length. Durin e irradiatioth g e silicoth n n ingo s oscillatei t d vertically and turne meany hydraulia b d f o s c drive. The neutron fluence is measured by means of Self Powered Neutron Detectors and at the preset value the irradiation is interrupted. The silicon doping inhomogeneity does not exceed 5 # in resistivity.

194 NEUTRON AGTYATION ANALYSIS

Netron Activation Analysis is an important reactor service, rendere r varioufo d s branche Nationaf o s l Economy. mads Ii t e mainlA reactoEW t ya r wher mediua e m rapidity, pneumatic rabbit facilit s constructeywa d twenty years ago. The parameters of the device are as follows: - thermal neutron flux - 1.9 .O 10 -2j n/cmfsec - maximum temperature - 60 °C - tim f fligho e t froe reactoth m r e analiticatth o l sec5 laborator - . y The facilit s extensiveli y e analyticayth user fo d l services e followin e th mos th d te an characteristicar g : - semiconductor impurities determinatio, nGa , /traceAs : of s Au, Mo, Zn in silicon/ for the Electronic Industry. - impurity determination in aluminium /Mn, Cu, As, Sb, Sm, Se, Cr, Qa/ for Aluminium Metallurgy. - analysis of samples for the Geological Search Service. - plant r analysi, ai wate d r Jnvironemenan rsfo t Control and Supervision Commission. - person identification by means of trace analysis of a hair e Criminologth r fo y Service.

GAMMA IRRADIATION

Stored under water shielding, spen e directltb fuen ca l y used for gamma irradiation. The utilisatio f speno n t gamma fue s a la radiation strong source, was initiated twenty years ago for the bone tissue sterilisation. It was made for the madlcal transplantation e objecanth d f sterilisatioo t s submergewa n d inte reactoth o r core directly after the reactor shut down.

195 Nowe biologicath , l material sterilisatioe th s mad i nt a e accelerators. However, the reactor spent fuel is always used for gamma irradiation. Some rubbee tonneth f ro s late rectiulates wa x y meandb f o s gamma radiation in EWA reactor spent fuel storage tank. On tha te sixties w materiawayMedicae th ra th n ,i e r th ,l fo l Gum Factory was prepared. It was made in a simple irradiation stand, in a 15 Uter volume container, with a dose rate of about 0 kRad/hour70 . Nowadays, the reactor spent fuel gamma radiation is utilised for some madical equipment sterilisation. Into a water-proof container of a 500 liter volume, in MARIA reactor storage pool, with a dose rate of about 3 MRad/hour, some thousand of surgery dresses per day are sterilised. EWA reactor spent fuel storage tank is exploited for the apparatus testing. Int n irradiatioa o n stand, wit dosa h e rate of 300 kRad/hour, the control and measurement equipment for nuclear power plants is tested.

TEACHING AND TRAINING

The experience in Nuclear Reactor Technology as well as in Radiation Protection of the reactor staff, makes possible to maintain a teaching and a training activities, vera r y ?o long time e researcth , h reactor n Polani s d have been taking advantage for training of students of Technical Universi- e Collegth f n Nucleao o e tie d an s r Energy. Last time, the special school for the staff of the First Polish Nuclear Power Plan s beetha n organized.

196 Another example Traininth s i e g Cours Researcn o e h Reactor Technology organize invitation o d e Internationath f o n l Atomic Energy Agency for a group of Syrian engineers and scientists monto tw he Th duratio. n cours will take placn i e some weaks. The Reactor Staff is also in charge of the Public Education. On every weak, when one of the reactors is shut down, organized group e Instituts th com o t e f Atomio e c Energy where th e research reactors as well as the radiation protection systems are presented by the competent personel. Each presentation is precede lecturea y b d . s estimatedIi t , that durin e las 5 th yearsg2 t , aboua t hundred thousand person s aquaintewa s d witnucleae th h r reactors.

REFERENCES

/1/. Aleksandrowicz J.,Szulc P. "The First Nuclear Reactor in Poland«, Nukleonik 27-41, 3 a , /1958 n Polish/i / / /2/. Aleksandrowic al.,"Increasint e . zJ A ReactoEW f o g r MW"0 Powe1 o ,t r Pap o Internationat . l Conf Reacton ,o r Physics and Technology, Budapest 1965, /in Russian/ /?/. Byszewsk t al.e . ,v/ i "Polis h Test Reactor MARIA", Nukleonika, o 11-1volN , 2 .21 /1976/ /4/. G-oncharov V.7. et.al.,"The ÎÎR Research Reactor for Testin Fuef o g l Element d Materials"an s , Proc. 3-rd Geneva Conf w York.Ne 1964N ,U , 19657_ , , 314. /5/. Kubowski J.,"Developmen Dynamia f o t e c th Mode r fo l Research Reactor MARIA", Nuclear Technology, vol.47, 1980. /6/. Sorokin A.,"Dissociating Nitrogen Tetroxid Workina s a e g Flui n Thermodynamii d c Cycles", Nucl.Sc.and Eng.,72, 1979.

197 111. Geliriski Z.,Kozie£ J., "Loops and Rigs with Dissociating NpC MARIn o K A reacto r G-GFBfo r R Programme", Nukleonika, vol. 26, No 4-5-6, 1981 /in Russian/ /8/. Blinowski K. et al., "Polarised Neuton Spectrometer SSN-2 at MARIA reactor at Swierk" Journal de Phisique, Coliqu , , tom, suplDecembe12 07 e43 eo H . r 1982. /9/. Ligenz , "DynamicaS. a l Natur f Superexchango e e Interraction ...,.", Phys. Stat. Sol. 130, 1985.

198 UTILIZATION OF THE JEN (MADRID) EXPERIMENTAL REACTORS IN SUPPORT NATIONAE TH F O L NUCLEAR PROGRAM

. ALCOBEV R Reactor JEN-1, Junta de Energia Nuclear, Madrid, Spain

Abstract

The Junta de Energia Nucleares installed a 2 MW, MTR type research reacto n 19b8i r . Operatio e reactoth t s suspendeo n wa r n 1984i d A . historical review of the operation of the reactor is presented with some insight as to the causes of the reduction in utilization of the reactor. Some ongoing activities as well as plans for the future use of the JEN-1 are presented.

INTRODUCTION

Alon e lonth g g li e dJEN- storth f o y1 research reactor

(critical since October 9, 1958) and in connection with the topic of the meeting we can distinguish three stages:

1. The traditional situation (since its start up until 1980)

- The reactor was dedicated to the isotope production, training (in this reactor most of the personnel of NPP have been trained) and, in a minor proportion, to NAA.

- The collaboration with the University and Research Institutions was very limited.

- There was not any kind of collaboration with the nuclear in- dustry.

2. Last immediate situation (since 1980 until the middle of 1984).

- Decrease of the isotope production and training.

- Light increas e collaboratioth f o e n with Universitied an s another research institutions.

- There was not any kind of collaboration with the nuclear in- dustry.

199 A limitatio - e reactoth f o nr power (lO ) followeOkw e th y b d suspensio l operatioal f o n n activities (Jun , 19$418 e ) with the purpose of renewing or replacing several old systems connected securitye witth h .

3. The recent situation (years 1985 and 1986)

- The reactor is stopped and discharged.

- The works of the renewing project (ventilation, electric wiring, liquid effluents tanks, electronic wiring, etc.) until a total of 22 subprojects are proceeding on.

- The future operation plans are being elaborated. e futurTh . e4 situation (since 1986)

e purposth s f elaboratineo ha N JE e Th Nucleaa g r Tech- nology Program, firstly at a domestic level and later at a national scale. Within this progra n increasa mgenerae th f eo l activitie e JEN-th CORAd f 1o san L reactor s wela s s anothela r JE\ installation are considered for the support of the coun- try requirements.

n thiI sconnection i pape d an r n wite purpose th h th f o e meeting, those projects planned to run since the starting of the JEN-1 operatio t together n pu 198i n e 6ar . From the considerations made in this introduction it shoul concludee db d tha experiencr tou collaboratioe th n ei n with the nuclear industry in the field of Experimental reactors is very limited. Nevertheless we expect to break out this trad^L tion and start to consider several problems connected with the nuclear industry in the country.

200 SUPPORE FISSIOTH O T TN TECHNOLOGY

Ther s beeeha n traditionally i_n Spai stild laca f n, an o klis agreement between the research plans and the real requirements of the nuclear industry e consequencTh . e stronth s i ge external dependenc- se n i e veral industrial fields.Wit f reducino m ai e g th hthat n approxi,a - mation amon e publith g privatd an c e bodie beins i s g intendee b o t d implemented t presenA . nationaa t l research progra s beini m g elaborated. Although the program is not concluded, the fact of its elaboration shows an interest of all parts involved to succeed.

Therpurposa s i e o constitutet ea nationa l group with the aim of preventing problems and creating an approximation among NPP, companies of services and the JEN. Some projects in which the e rol th f coordinatio eo s JEha N e followingth e ar n :

1 . National program on Intergranular stress-corrosion.

The experimental reactors utilization is not foreseen.

2. Radiation embrittlement of pressure vessel steels

Two projects are being developed. The first one is coo£ dinated by the I.A.E.A. and the second has a national extent.

2.1 In this project seven kinds of probes are to be irradiated e JEN-th n 1i reactor into capsule o simulatt s e reaeth l cori dition f temperaturso vessele th n ei .

2.2 In the above mentioned national project, some welded mate- rials shoul analysise e addeth db o t d . These studiee ar s the extension of the thermal embrittlement to the case of irradiation.

3. Program of steam generators

f experimentao e us e Th l reactor t foreseenno n i s .

201 4. Noise analysis in NPP

Noise studie e beinar s g develope n somi d e NPPA . coordination and encouragement in this field is necessary. The installation of Thermohydraulic circuits in the JEN-1 and CORAL is being considered.

. Developmen5 utilizatiod an t f gammo n a thermometers

It is presumable to build some prototypes and test e JEN-th the n 1i m reactor.

There are another subjects in the mind but they are purpose projecty th an t no f ye ter o instanc .Fo et therno s i e a resolution about fast reactors n anothe.I r projects (PISC- -III, TRANS-RAMP and LOFT) the irradiation in the JEN-1 reac t expectedno tos i r .

SUPPORT TO THE FUSION TECHNOLOGY

There are three proposals of the JEN to be included inte EURATOth o M projec f financieo t d activitie e perioth r dfo s 1986-89 o develoT . N collaboratep JE thee th m s witUniversie th h - ty, another national and foreing organizations as well as with the Industry.

1. Low activation alloys

Three objectives are implemented in the search of low activation alloys to be used in Fusion reactors:

a. To handle those materials as a class C radioactive waste,

. Securitn accidentb a e cas th f . Possibilit o ec n i yd an , f o y performing maintenance and repairing operations in the reac: tor .o objectives Thertw e ar e :

20: a shor 1.t A 1t tern collaboratio(i m n with KfK )chooso t e one martensitic steel and to achieve the "Low activa- tion" material by replacement of some constitutive el<; ments by another less activable ones.

t shoulI e necessab d o desigt y n some capsuleo t s irradiate the materials at a high temperature in the JEN-1 reactor.

a lon 1.t gA 2 term

To find out materials fulfilling the three objectives proposed.

2. Radiation effects on insulating materials

o studT e behaviouth ye refractarth f o r y inorganic insulator o severast l operation condition n particulai s e th r high frequency dielectric characteristics. At present the rruj terials shoul e irradiateb d d with electron d gamma-rayan s n i s an accelerator. Neutron irradiatio e futureth n n i wil. o d l

3. Thermal cycling of components for Fusion machines in the solar platform of Almeria.

f experimentao e us e Th l reactor t expecteno n r i s fo d the moment.

Ther e anothear e r subject n whic i se experimenta th h l reactors should be involved but they are not materialized into proj ects.

203 SCOTTISH UNIVERSITIES RESEARC REACTOD HAN R CENTRE

J.A. IZATT Scottish Universities Research and Reactor Centre, Glasgow, United Kingdom

Abstract The Scottish Universities Research and Reactor Centre was established in 1963 to provide teaching, training and research facilities to all Scottish Universities e CentrTh . eArgonau W includek 0 30 t a styp f researco e h reactor. The jointly owned Centre has been highly successful, and other scientific disciplines have taken the opportunity to install research y severab equipmen e us l r universitiesto t a resul s e A Centrth .t s ha e diversified its interests beyond the normal topics pursued by reactor establishment s verha yw successfuno d an s l groups workin n geochronologyi g , stable isotope geochemistry, radiocarbon dating and nuclear medicine.

Introduction The Scottish Universities Researc d Reactoan h r Centre (SURRC s formallwa ) y opene n i Novd . 1963 o t provid, e teaching training and research facilities to all the Scottish Universities. The jointly owned Centre has been highly successful d othean , r scientific disciplines have takee th n opportunit o t instay l researc y hseverab equipmene us l r fo t universities a resul s e A Centrth . ts diversifieha e s it d interests beyond the normal topics pursued by reactor establishments and now has very successful groups working in geochronology, stable isotope geochemistry, radiocarbon datin d nucleaan g r medicine. The financial climate for universities in Britain at the present time is rather bleak, and recently some of the smaller universities have found it necessary to withdraw from the consortium, and the Centre is now owned by three, Glasgow, Edinburg d Strathclydan h e Universitiese th f o o Tw . others retain an associate interest only in the geology department.

205 e resultth f o f thes o se On e change s thae i Centrs th t e has to try to earn money to offset some of the costs, so that n additioi o universitt n y functionsw requireno e ar o t de w , seek commercia e pasl th e havw work tn I e . offered services to industry but the response was poor in the reactor-related topics.

Reactor The reactor is a 300 KW tank type reactor, water moderated, graphite reflected, with highly enriched uranium n fuelflai e fue Th s ti .l aluminium plates with uranium oxide in the original fuel, and metallic uranium in plates supplied more recently. e maximuTh m thermal neutro x 10 8 n1 23. flun cm" s i x 2 sec" d maximu1an , m fast neutron ~ 10flu s i 1x 2n cm"2 sec"1. The reactor normally operate 3 day0 r 30 a wees fo st a k e irradiatioth t bu W K n programm s veri e y flexibls i d an e varied to suit research requirements. There is an annual shutdown of 3 to 4 weeks for maintenance, usually during the early summer.

Radioisotope production In the United Kingdom the supply of radioactive material d labellean s d compound s beeha s n covered mainly b y the Rad iochemica1 Centre, Amersham, and the supply of radioisotopes from 5URRC has been limited to short lived isotope e mainth n .i s However, becausr geographicaou f o e l position and willingness to supply at short notice, there has bee n increasa n e numbeth n f customeri o er e lasw th fe tn i s months e followinTh . e mor th e som ef ar go einterestin f o g these

206 18Fluorine (112m). Using a reaction of tritium on oxygen,

fluorine is produced by neutron irradiation of lithium

carbonate. The yield is sufficient for the needs of a

university laboratory.

IlCarbon (20m). In this case lithium metaborate is

irradiate e reactorth n i d o product , e 11C, a use s a d

trace n plani r t studies.

(110m). To provide sufficient activity in the argon

e durinus r g fo normal working hours e reactoth , s wa r

operated overnight e isotop Th uses r . tracefo wa de r

measurements in a large industrial plant handling North

Sea gas.

Therregulaa s i e r deman r tracefo d r material r medicafo s l

and biological research, suc s copper-64a h , sodiu. m24

Neutron activation analysis

Neutron activation analysis (NAA) forms the major demand e reactoe presenth th f t o a e r t us time r fo . Samplee b n ca s

irradiated in two pneumatic transfer systems, or by loading

when the reactor is shutdown into the central graphite region

or the thermal column.

The counting arrangements for the laboratory have

recently been updated and a diagram is attached showing the

facilities available to users. There are four terminals

available giving access to the main computer, a DEC PDP11/73

Data Acquisition and Analysis system, and there is capacity

e systeth n o increasi mt e this e presennumberth t A t. time

the system is operating ten detectors on approximately 24 hr

y schedulesda r pe .

207 Most of the NAA projects are carried out in association

with department e supportinth n i s g universities.

Many thousands of samples are irradiated and analysed

each yea n i manr y scientific disciplines suc s archaeologya h ,

geology, biology, engineering, and zoology.

Neutron beams

Apart from neutron beams user teachinfo d g experiments

the only current applicatio r neutrofo s i n n radiography.

Neutron diffraction and capture y analysis facilities were

installed several years ago but have now been removed.

Neutron radiography

This technique, complementary to X-radiography, enables

us to locate materials with high neutron cross section in

structures or matrices of relatively low neutron cross

section. At SURRC the neutron radiography facility is a

simple tube channeling neutrons froe thermamth l columa t a n

point wher e neutroth e n flu s i 10x 1n cm"1 2 sec~l wita h

cadmium ratio of 150, giving a beam current at the reactor

face of ~ 106 n cm"2 sec ~l .

e generath n I l arrangement graphita , e source blocn i k e e centrthermath th f o e l column scatters neutrons dowe th n

beae mth e , distanctube e beaTh m. th .5 m o 2. t eexi s i t

collimator is 50 cm long and 15 mm diameter. Most of the

radiographs are taken 4 m from the collimator exit where the

neutron flux is of the order of 5 x 101* n cm"2 sec ~l. The

collimator size can readily be increased to give higher

neutron flux and greater beam size.

208 Gadolinium conversion foil is used and exposure times with Koda 0 min1 k o .t Industre e orde5 th f o f ro D filxe ar m Recent work undertaken has been an investigation of water levels in the reservoir of a high power heat pipe, and the investigatio e content th n Egyptia a f o nf o s n bronze

falcon, which is estimated to be 2000 years old. At that time the casting was sometimes sealed up with a number of bones fro a smalm lr preliminar birdou d an , y investigation showed something of this nature in a casting from the Burrell collection, recently housed in a new museum in Glasgow. Consideration has been given to installing a beam plug with filters for y and fast neutrons in one of the high flux t beeno e ncoss th justifiedha tbear fa m o tubess t . bu ,

Irradiation services Use has been made of the reactor for various applications in different scientific fields. For instance, an investigation of continuous casting of brass used an activable trace o detect re solidificatioe shapth th tf o e n front during operatio e furnaceth f o n . Whee planth s n wa t operating under steady conditions small injection of indium was introduced to the melt just at the entry to the die. The e castinth par f s identifieo twa g a thi d nan d sectios wa n irradiated to activate the indium which was then used to produc n autoradiograpa e e solidificatioth f o h n front. The autoradiogrphy technique has also been used to enhance the detail in old faded photographs (~ 1870). Irradiatio e reactoth n i n r activates e silvefadeth n di r image, which is then used to produce a positive on film by autoradiography. Since the technique is non-destructive it

209 is a useful way of examining rare and therefore valuable photographs.

Cobalt irradiation rig A small cobalt irradiation rig was constructed several e wateth e n reactorri th year tan o f o ag ks , taking advantage a facilit f o n greai t yt no whic demands wa h . While th e irradiatio m highc e dos2 3 )th x e a n di spac m c s smali e 5 (2 l rat s madf -300 o eha t ver i ey 0G y usefu r pilofo l t studies, and it is very much in demand. In recent years it has been used for:- sterilisatio f smalo n l quantitie f surgicao s l supplies,

irradiatio f monomero n polymerd an s r crosfo s s

linking and polymerisation research projects,

treatmen f agriculturao t l samples,

pilot studie f o irradiatios n treatmenf o t

potatoes,

irradiation of fish eggs in fish farm research.

Stud f behaviouo y f insulatino r g materiaK 4 t a l

A research projec s i underwat e presenth t a y t timo t e

investigat e effecth e f radiatioo t insulatinn o n g materiat a l

4K. The neutron dose in the centre of the reactor is a

reasonable simulation of the dose expected to be delivered to

the insulation of the superconducting magnets in magnetic

confinement fusion reactors sometim e futureth e Th n i e .

experimental facility has been operated so far only in the

cobalt rig at a dose rate of 7000 Gy, but will shortly be

installed in the central vertical facility of the reactor.

210 Fission Track Dating

The technique of fission track dating involves the

selection of suitable mineral grains from a rock sample,

polishin a gsurface grainsth thed n o ean n , etchin o reveat g l

the tracks left by the passage of fission products from

uranium in the mineral. Subsequent irradiation of the sample

in the reactor, in contact with a track etch film permits

determinatio e uraniuth f o n m conten d hencan t e providea s e mineralth datr fo e . Sinc e damagth e e producee th y b d

products in different mineral grains is annealled out at

different temperatures some information can be derived about

the thermal history of the parent rock.

Support of Nuclear Poweer Programmes

Several research programme e beinar s g pursueo t d

investigat e effectth e f radioactivo s e materials released

into the environment.

137 n Ci coastas l waters around Scotland. These

investigations indicate that the caesium which is highly

solubl n seawatei e r travels froe fuemth l treatment plant

outflow at Sellafield around the coast of Scotland but the

levels are for the most part negligible, being 60-70% from

Sellafiel e resth td froan d m bomb falloute coursth f n o I e .

whole body measurement s i show t i ns that peopl livo n i ewh e

the islands off the west coast of Scotland have a

considerably higher body burden of caesium than those who

live on the mainland. Because of past releases it is now

estimate e totath f o l d worl% 5 tha ~ dt environmental burden

of » *s pcontainei u n sedimenti d e Iristh hn i sSea d an ,

239 21 0 the long term behaviou f thio r s materia f somo s ei l concern.

211 r investigationOu s indicate that o significanthern s i e t onshore transfer of contaminated sediment in the Clyde Sea aret significanbu a t transfer does tak ee Solwaplacth n i ye Firth, whica larg s i h e tidal estuary. This will undoubtedly continue to be studied in the future.

Analogue studies in nuclear waste disposal. Prediction of the long term behaviour of radionuc1 ides relies on laboratory experiments and thermodynamic models. Tests of such work can be provided by the study of natural geological systems which have properties analogous to some of e processeth s importan n wasti t e disposal A numbe. f o r project f thio s s type beinar e g carried out. Sediments studie n Loci s h Lomond. a largThi s i se inland bod f freso y h water. Howeve s knowi t i nr that between 6000 and 5000 years ago the region was covered by the sea, resultin e a sedimenregio th n i gf o n t 3 metrebetwee d an s2 n down f marinwhico s i he origin, sandwiched between regionf o s fresh water origin. Study of the diffusion of ions between these regions give a usefus l tes f diffusioo t n modelr fo s saturated clays. For instance, investigation of profile of iodine abundanc e sedimenth n i e t shows that thers i e substantial retention of the iodine in the marine sediment. Similarly natural deposits of uranium and thorium in granites permit e stud th sf diffusio o y f theso n e materials, e stud th f migratioo y n watei n r saturated fissures d studan , y of chemical effects of coatings in fissures. These studies indicate migration of uranium of only tens of centimetres in approximatel 6 years10 y .

212 In Scotland, a uranium rich shale deposit underlies 10,000 year old deposits in the flood plain of the Solway. A study is being pursued to measure the rate of migration of U an h froe T shald th m e inte overlyin 2 metreth o o t f o 5 s 1. g soil. Many projects are being carried out to measure effects f radioactivo e discharges froe nucleath m r fuel cycle. Some f theso e have been commissione e operatorth y b d f nucleao s r site n ordei s o havt r e independent measurement o supplement s t their own.

Jducatlonal applications using reactor related facilities Teaching courses are run for the universities in nuclear engineering, reactor physics, health physics, radiochemistry, and uses of isotopes. Training courses for post-graduate students and staff are run in activation analysis, health physics and uses of isotopes. These course r industr fo e als n ar sd hav ru o an y e proved popular and useful in making industry aware of the equipment and techniques available to them at SURRC. Some staff from the nuclear station of the South of Scotland Electricity Board have attended courses at the Centre either s para f theio t r introductio e nucleath o t n r industrr fo r o y refresher courses. A very large number of collaborative projects are carried out with University staff and with post-graduate students studyin a researc r fo g h based higher degree. So far attempts to interest the public in attending course o familiarist s e them wite nucleath h r industry have

213 met with little success t memberbu , f stafo s e callear f n o d to give talke e o Centrpublit th th n woro d so t t an a kec professional bodies.

214 INCORPORATING THE OPERATION OF A SMALL RESEARCH REACTOR FACILITY SUPPORO T TNATIONAA L NUCLEAR POWER PROGRAM

S H LEVINE, E S KENNEY Pennsylvania State University, University Park, Pennsylvania, United States of America

Abstract

A small research reactor similar to the Perm State Breazeale Nuclear Reactor, which is a 1 Megawatt TRIGA, can be invaluable in supporting a national nuclear power programme. The research reactor provides an operating reacto r traininto r g nuclear engineers, nuclear operators d othean , r nuclear specialists required to construct, operate, and maintain the nuclear power plant. When operation of the power plant begins, highly trained, well-qualified and competent personnel will be available to operate, supervise, and maintain a sate and efficient power plant operation.

The paper describes the organization of a nuclear science centre as well as research reactor activities n exampl A n actua.a f o weeo etw l k training programm n electria f o e c utilit s includei y d wit a lish f experimento t d an s demonstrations. University project d experimentan s s usin e reactoth g e ar r listed.

A small research reactor similae Penth no t Statr e Breazeale Nuclear Reactor (PSBR), (1»2) Megawat1 whic a s i h t e TRIGAinvaluablb n ca , n i e supporting a national nuclear power program. The research reactor provides an operating reacto r traininfo r g nuclear engineers, nuclear operatorsd an , other nuclear specialists required to construct, operate, and maintain the nuclear power plant.'3 A natio) n should first establis a nucleah r science center built around a research reactor several years before an order is placed for a nuclear power plant. Trained engineers and specialists will sav a natioe r morfa n e than they cost, s wel a s timea l , during plant construction. These trained engineers and nuclear specialists are needed when planning first begins and during the initial phase of the nuclear power program. Intelligent decisions made during procurement of the power plant can save costly changes during the construction. Problems invariably occur durin e constructionth g d trainean , d national e needear s o protect d t the owners' interests. When operation of the power plant beings, highly trained, well-qualified and competent personnel will be available to operate, supervise, and maintain a safe and efficient power plant operation. ^3)

A typical nuclear science center will contain a research and training reactor and supporting facilities as outlined in Fig. 1. The research reactor provides a source of neutron and gamma rays that can be used to tesd supporan t t developmen f producto e twit e nucleaus th h r fo s r power plant. For example, detectors, radiation resistant products, and products o isolatt e radiatio e itemth e sf nb o wasttha n w ca tfe e a productt bu e ar s developed. Measurements made with the reactor itself support such broad areas as neutron and reactor physics, radiation shielding, and radiochemistry. '^' The number of important research programs that can be

215 Nuclear Science Center

• Research and Training Reactor

Isotope Support Facilities (Production, Use and Disposal)

• Instrumentation Support Shop Laboratoried an s s

• Physic Engineerind an s g Laboratories

• Health Physics Services

• Chemistry and Chemical Engineering Laboratories

Fig. 1 Major Functions in a Nuclear Science Center

REACTOR OPERATOR NUCLEAR SUPERVISORS ENGINEERING MAINTENANCE IABORATORIES QlAim CONIROL

RAD I\TIPN

I'1-CORE FUEL MANAGEMENT FJFL ElLMENT STIDIFS FISSION PRODUCT STUDIES

FiEL MANAGEMENT

NEW PRODUCTS ^FACTOR SAFFTV \FUTRON RADIO .WPh - 1 DETECTORS ACCIDENT ANAÎYSIS CO-60 FACILH"- DOSIMETERS SHIELDING T CELL40 S INSTRUMENTATION MICROCOMTUTFRS NON NICLEAR RESEARCH ISOT3PE PRPDLCITON DEVELOPMENT SAFETY IRRADIATION SFPATCFS

RLSEAjiCH REACTO I TIT V I ST AC R

216 performed with the research reactor is limited only by the number of qualified personnel assigned to the facility and the funds needed to support them wite appropriatth h e laboratorie d instrumentationan s . Fig.2 depicts the research reactor facility and some of its various uses.

The research reactor facilit a majoe use b s a dn r ca ycente r that touches every aspect of nuclear power technology.^3) Safety requirements can be defined and practiced to train personnel for the safe operation of the plant. For example, selected rules and procedures used to operate a nuclear powe re practice b plan n ca t d wite researcth h h reactor. Reactor safetf primaro s i y y importanc e operatioth n i a nucleae f o n r power plant. Reactor power plant personnel should be taught to evaluate solutions based on safety considerations first and economics second. Extra safe solutions to a problem can be evaluated both in terms of safety and economics. The safety solution to this problem can then be reduced to make the costs economical but still maintain more than adequate safeness. Solving the identical problem to find the cheapest solution is wrong. The cost between the two approaches may be small, but the differences in safeness can be e lonlargeth gn I run. , this attitude will save money. Health Physics requirement a nuclea r fo s r powe re define b plan n ca td and established in the research reactor facility. The research reactor facility require a healts h physics staf d equipmenan f r saffo t e operation. Augmenting these facilitie o providt s e adequate health physics supporr fo t a nuclear power plant is a superior method for implementing this type of program. e healtTh h physics function a powe f o sr plant operation require careful implementatio o providt n e effective monitorin d regulatioan g f o n radiation work. Professionals in this work are generally practitioners in contrast to research scientists or engineers. Therefore, the need for an extended internshi n environmena n i p s closa t s possibla e e th o tha t ef o t power plant is important. By establishing and operating a Nuclear Science Center a natio, n providca n n experienca e s poweeit patrr planfo h t health physics personnel which incorporates into their training local geography, government and culture. In addition, the interconnections to local supporting technologie e establishear s do medicine t suc s a h , metallurgy, instrument manufacturing, etc. Like all of nuclear technology, health physics is advancing rapidly. Power plant personnel are usually committed full time to service functions e reactoth n o r station s difficuli t I .r the fo o statt m y abreasw ne f o t techniques and equipment. The health physics operation at the nuclear science center can continue to perform a research function after the nuclear power plant is in operation. The functions of research and general trainin n healti g h physics can, therefore e performeb , e centeth t a rd with confidence that modern technology is being incorporated into the plant operation.

n examplea s A e reactoe Pennsylvanith ,th t a r a State University (License R-2) was originally built to support University research. The original reactor facilit s showi y n n 1962n FigmarkeI i t - .,3 ou d expansio s undertakewa n o upgradt n e ratheth e r limited facilit o includt y e e essentiath l element a nuclea f o s r science center e n growti Th .s wa h respons a vastl o t e y expanded nationa d internationaan l l rol f educatioo e n and training which develope e reactorth r r reactofo Ou d. r facilitn a s wa y important training center in the international "Atoms for Peace" program instituted during President Elsenhower's administration. In 1965 a 1 MW

217 FIRST FLOOR PLAN

PENN STATE BREAZEALE NUCLEAR REACTOR GROUND FLOOR PLAN SCALE 1M6" » r-O' Unittd States of Amtnca 1986 Fig. 3 TRIGA core d drivero , d instrumentatioan s n packag s installewa e o replact d e the original plate-type highly enriched uranium reactor.

At Pen ne performinStatar e w e g betd neutroan a n dosimetry measurements unde n independena r t contract wite Pennsylvanith h a Powed an r Light Company (PP&L). Field measurements of beta doses are not accurate particularly when gamma ray e alsar s o present A bet. a dosimetry laboratory is being establishe o develot d p superior technique n performini s g beta dosimetry measurements.^) Developing such techniques utilizes beta source f differeno s t energies e PenTh .n State research reactor providen a s excellent array of beta sources to supplement those beta sources procured from a manufacturer. New techniques are being developed to provide greater accuracy in both neutron and beta dosimetry measurements.("' Such measurements are to be performed at the nuclear power plant in close cooperation wit e PP&th h L health physics staff A majo. r objectiv f thio e s o providt wor s i k e PP&L wit n independena h t quality controe standarth n o l d dosimetry monitoring of the workers at the nuclear power plant. The basic principles of in-core fuel management are the same for the research reactor as for the nuclear power reactor. In both cases, the power distributio e coree burnu th e kth e n th ff,d i n p ,an characteristicf o s the fuel must be determined as a function of core life. The same basic calculational techniques are used for research reactors and nuclear power reactors nuclead an r power reactors, however e strategth , r corfo y e operatio d reloaan ne differentar d . Wite researcth h h reactor e highesth , t neutron flux is desired throughout the core life, and operation at full power does not approach any safety limit. In a power reactor reliable energy production at an economical price is the main goal. Studying the effects of changing fuel configurations in a research reactor provides excellent insight and understanding when performing the same tasks for a power reactor n additionI . , experiment e performeb n ca s o validatt d e calculational technique r complicatefo s d conditions. Characterizing depleted fuel, reactor diagnostics using noise analysis techniques d meterology-typan , e experiment e studieb n ca ss and/or performed usin e researcth g h reactor facility.(3 f importanco ) e facth ts i ethae th t research reactor provides a focal point for locating the experienced personnel who can teach, train, develop, and perform research on all aspect f nucleao s r power plant constructio d operationsan n . Reactor operation training program e givear s t Pena n n Stat r powefo e r plant operators and supervisors.'?' In addition, a special program was developed to train the TMI-2 reactor operators on the characteristics of subcritical reactors n thesI . e training program e reactoth s r operators were given hands-on training with nuclear equipment in support of the lectures. It is essential thae reactoth t r operator e traineb s d using equipment rather than pushing buttons on a computer and only listening to lectures before or during their nuclear power plant training. Hands-on experienc s vitai e l for training nuclear power plant personnel. An example reactor operators training progra s includei m s Figa d 4 . and Fig , showin5 . e essentiath g l topics designe r presentatiofo d o t n personnel without previous nuclear experience. In practice, nuclear utilities have frequently used this type of program as a review prior to licensing or requalification exams. Working with two groups of four operator so wee ovetw ka r period, lectures, laboratorie d reactoan s r console experience are intermeshed to provide a concentrated learning environment. By design, an operator trainee spends four hours at the reactor console and four hours in lectures and laboratory work each day. TJESDAY «i^DHESDAY THlhSDAY FRIDAÏ

3 & H June « & 18 .ure 9 ' Jun 4 5e 6 4 20 June

H i B A A A A 4 3

rtelcore , To^n, S„tcn tical "i'-st Irdicat.»on Doubling Time Approaco t n Multiplication of Temperature Tec-nique and Critical TO Procedures , and Inst^jrentat ion Effects Servo System Experiment Fariliarlzaticn

LUNCH -UNCH LUNCH L-JNCri LUNCH

A A 4 5 A 4 b A Ä B A & B

Ciec^out, Rod Lessons „earned Flux Mapping Radiological Continue Dro"ra.ed an p i 1rs t"LTeitaticn and void Safet> Survey Approaco t h Ti-nes, Co-sole Exper.-eit Effects and Instrorents Critical ~ani A ia-ization Experiment

DINNER DINNER

.6CC

D 5 d B

Checkoutd Ho , Subcri tical Fjrst I nc lea t ion Doubling Tire Drop and ""'•avel Multi plication of Tenperatu^e Techniqud an e TO Times, Consc.e Effects Servo System Famii iarl zatlon

2000

Tig. U FIRST V.EEK SCMt-DLLE FOR PHILADELPHIA ELECTRIC COMPANY

RhT PROGRAM 2-6 JUNE AND 16-20 JUNE 1980

MONDAY TUESDAY WEDNESDAY T-luRSDA.Y FRIDAY

« 4 23 Jure 10 4 2 1 June 1 1 S 25 June 12 4 26 June 13 4 27 June 0700

A A A A A 4 B

TO IirDU" Equatior Temperature Sqjare i^ave Reactor Water Approximat ion Coefficiend an t Operations Transient Chemistry Hot Start-ups Operations 1100

LJNC1 LUSCH LUNCH 1130 A 4 B B 4 A A 4 B B 4 A A 4 B

îod Calibration Xer.od an r Neutron Radiation Safety Mock NHC Experiment Samarium Analog Shielding and "Sui ting-up" Console Exaf Computer Backscatte" Decoita-il nation Demorstratlon Exercise 1530

DINNER DINNER DINNER DINNER 1600 B B B B

Inhour Equation Temperature Square Wave Reactor TO Approximation Coefficient and Operations Transient t Start-upHo s Operations

2000

Fig 5 . SECOND WEEK SCHEDUL R PHILADELPHIFO E A ELECTRIC COMPANÏ

RRT PROGRAM 9~13 JUNE AND 23~27 JUNE 1980

220 The NRC requires a set number of reactivity manipulations for licensing and requalification. This program satisfies this requirement by allowing each trainee to perform at least ten start-ups. A large repertoire of nuclear lecture topics and experiments have been develope e sponsorinth d an d g power utilit n customizca y e programth e o t s match the level and type of personnel they have selected for training - r facilitOu . s regularl6 Figha y . y performed program d eve f onean o s n o ,tw six weeks duration. Conflicts have developed between research, education and training utilization of the facility. The research reactor continues to be useful long after the nuclear power plant has been in operation. It can be used to develop new solutions to problems encountered during operation. For example,at Penn State a new metho r measurinfo d watee th g r n operatinlevea n i l g light-water nuclear power plan s beini t g developed.^ e TMI-Th ) 2 accident showe a needr fo d measuring the water level in the pressure vessel of a light water reactor.

To "tailor make" an individual program, the utility's specific needs, any or all of the following topics can be included. Another alternativ o suggest s i e a topit t listeno c e reactodth herd an re staff will desig n experimena n r demonstratioo t o illustratt n e th e concept.

• Critical Mass - fuel addition or rod withdrawal

• Control Rod Calibration - positive period method

• Neutron Backscatte Shieldind an r - gPu-B e sourcea d an s neutron howitzer

• Flux Mappin - grhodiu m detector^ in-corBF r o e s

• Negative Temperature Coefficient Determination • Void Coefficient Determination

• Verification of Simplified Inhour Equation

• Cambelllng Proces - spowe r level versus reactor noise

• Reactor Transient Behavio - prompr t criticallty

• Nitrogen-16 Activity in Water

• Gamma Exposure Rate Measuremen - Cobalt-6t n watei 0 r

• Radiatio f variouno Survee us s - yinstrument s

• Decontaminatio - n"suitincleanind an " p up gu g

• Cloud Chamber - a "look" at subatomic particles

t Demi neral izer Evaporatord an s - spractica l water che-iistry

• Xenon and Sanarium Poisoning - analog computer denonatration

• Mock NRC Operations Exa - mSRO' s simulate NHC exar.iners

Fig. 6 Choice of Experiments in Utility Training Progran

22! During the TMI-2 accident, data from the source range detectors indicated a possible relation between their e densitoutputh d d levean an t y f coolano l t e reactorith n . Usin e TMI-th g 2 data ,a concep a non-invasiv r fo t e liquid level gaug s beeha e n developed usin e PSBRe PSBth gTh R. experiments simulated conditions in a partially voided reactor. The system is now being tested at the LOFT facility. New techniques are also being developed for monitoring the isotopic content of radioactive effluents released under abnormal conditions fro a nucleam r power w methoplantne r A fo d. measurin e subcriticath g l reactivit e damageth f o yd TMI-2 cor s beini e g developed using the Penn State TRIGA reactor.^)

A research reactor facilit e useb o provid t dn ca y e several major service functions including neutron activation analysis, low level environmental radioactivity monitoring, and neutron radiography. Environmental monitorin a practica s gi l radiation measurement function resulting froe nee o th establismt d h pre-operational background levels around major nuclear facilities. Once this type of laboratory exists, it can service radioisotope laboratories, hospitals and power reactors. A technical w leveadjunclo a l o laboratort t n activatioa s i y n analysis facility. Practically, such labs should be physically separated with the low level lab located at a safe distance from the reactor to prevent background disturbances.

Neutron radiograph a growin s i yd importanan g t research reactor function. Û UsinthermaD2 a g l column a neutro, n radiography facilits ha y been establishe e PSB th - FigR t . a d7 .Usin g electronic image intensificatio d indiuan n r gadoliniuo m m thermal neutron converter screens, useful live-time e producedimageb n ca s . Unlik r Y-rao X e y images, thermal neutron imagin s abli go differentiat t e d imagan e e base n hydrogeo d n content. Plastics, oils and other organics produce good contrast with- neutrons rather than density or mass as in X-ray images.

B Ute.' H DIsV-

^ Collinator

222 Educating nuclear engineer n practicai s l reactor n operatioa e b n ca n important function of a Nuclear Science Center. At PSBR, we provide laborator d operationan y s experienc o student t ee graduat th t a d s an e undergraduate level e alsW .o provide laboratory experienc r 2-yeafo e r nuclear associate degree students who receive their major course work at other university geographical centers A lis .f experimento t s performen i d conjunction wit r reactoou h r facility appear s Figa s . 8

Experiments in Nuclear Engineering M51 , Reactor Physics Laboratory

I. Reactor Gar.ra Ray Field - Measurement and Calculation

. II Contro d CalibratioRo l d Temperaturan n e Coefficient

III. Reactor Transfer Function Measurement

IV. Reactor Pulse Measurement (large reactivities)

V . Reactor Noise and Vibration Analysis

VI. Analog Simulation - Xenon and Samariun Poisoning

VII. Digital Simulatio - Powen r Throttle Transient Response

VIII. Diffusion Length in Graphite

IX. n Graphiti FERM e Ag I e

X. Buckling - Natural Uranium Sub-critical

•I. bata Acquisitio d Controan n a Microconputevi l r

Fig. 8 SECOND SEMESTER LABORATORY FOR SENIOR UNDERGRADUATES

Other nuclear engineering e reactocourseth e us rs either directlr o y as a resource facility. A required nuclear laboratory course in Penn State's B.S. program, stresses radiation detectors, counters and associated electronics. The reactor is used as a source facility providing neutrons, gamma rays and radioisotopes. Students use BFj counters, Reactor Ion Chambers (CIC's and PCP's) and the usual GM, proportional and solid state GeLi spectrometers. Sharing equipment between research, training and education provide mora s e affordable experienc l concerneal r d fo e an d allows purchase of modern equipment. We are presently purchasing additional micro-computerized laboratory equipment to improve our education d traininan g capability.

223 A reactor operations course is offered twice a year to limited enrollment. This course stresses console operation with practical experience in safe normal operation as its focus. We have added a new course (Nuclear Digital Instrumentation) which encompasse e rapidlth s y developing rol f microprocessoro e d computeran s n nucleai s r technology. This course features basic digital machine function, machine code, digital interfacin d projecan g t design. Students develop such systems a s multichannel sealers, programmable counters, robotic radiation surveyors, CRT displays, etc. Again e researcth , h reactor provide e radiatioth s n fields and sources and the instrument shops necessary to maintain the computer equipmen d construcan t t mechanical parts.

Nuclear power is not the only function of a nuclear research reactor. n enormoua Tner e ar e s numbe f researco r h program e supportesb than ca t o t d improve the quality of life in a country. A few of such programs conducted at Penn State are as follows:^-1

The facility is being used by the Biology Department for several researc e morh th programse f o interestin e On . g project a progra s i s o t m stud e effecttn y f acio s d rai n fisho n . Body sodium influ d effluan xe ar x the characteristics studied on amblystomated and ranid larvae placed in sulfuric acid solution t pH'a s s d 4.0betwee.an 0 3. n

The Dairy and Animal Science Department has a significant program to determine the particulate digestive flow and nutrient digestibility in ruminant animals using activated rare e digestivearthth s a s e narkers.

e FooTh d Science Departmen s studyini t g improvement n processini s g efficienc d qualitan y f cultivateo y d mushroom products using gamma radiation to destroy bacteria in the mushrooms. Titles of other interesting projects being conducted at the PSBR by various departments e showar . Fign 9 i n. .eco P~ t Department

"Pee Integurenth n rreabif e o th y t f -i o t 3iology Department •^orseshoe Oabto Wate", Sodiu d Bromidean m '

tJ) 'Adaptation f Oocodileo s r L^ffo sn i e B.OiOgy Department Sa ine Wate"1

'hxperitiert for Anian Exchargp of Su-faric Chemical Erglreemg ^cld Usin? Radioactive Trace f 3ulfer-35o r "

'Effec f Padlatioo t n Glaso n s FiCer Epox; .natesm _a " Erginee"iig Science and Mecnani es Department

el 'Trace Element Analysis cf Rain Water" Phvsics Department

i '" Copper -lorreostasl KinetiA - s p A c Poultry Science Deoartrent

gl "Preparatio d -i/drogenaticar n n Studief o s Po^/ter Science Rhodiu ) I Catalysm t Suppor r P.gio t d Department Polyer Crystalline Surfaces" -

(h1! 'Immjrologica d -lectrophoretian l c «eterinary Science Investigatio f Genetio n c Diversity Department n TuTKeysi "

'ig. 9 Partia^ Lis f Titleo t f Otheo s " Prov ects Being Corducte^ e th t a d

224 In summary a researc, h reacto n providca r e bote facilitth h d an y experienced personnel needed to establish nuclear power economically in a small developing nation. Thi sa bonu suppore b s n whilca t t providei e r fo s many other researc d educationaan h l activities.^'

REFERENCES

Ross, D. A., "The Pennsylvania State University TRIGA Reactor Description, Initial Testing d Firsan , t Three Year f Operation"o s . M.S. Thesis, June, 1969. d Levine, "Penan H. , . nS S. , Stat Totenbierm Ki e, BreazealE. . R , e Reactor Operations Management". Proceedings ANS Topical Meeting on Reactor Operating Experience, Scottsdale, Arizona, August 1-3» 1983- IAEA Report on Consultants' Meeting on Safety Research and Training with Research Reactor Facilities, Vienna, Editor, Reijonen, H., December 13-16, 1976. Twenty-Eighth Annual Progress Report of the Pennsylvania State University Breazeale Nuclear Reactor, Editor, Totenbier, R. E., August 1983.

Levine, S. H., Chang D., McMaster, I. B., Yoder, R. C., and Miller, D. W., "Bet y DosimetrRa a y Measurements Usin e Lucitth g e Bety aRa Dosimetry Platform (LBIP)", Proceedings for the International Beta Dosimetry Symposium, Washington, D.C., February 15-18, 1983. Final Report to the Pennsylvania Power and Light Company Contract on Beta Dosimetr d Neutroan y n Energy Spectra Measurements. Levine. H . S , and Catchen, G. L., August 1983.

Penkala, J. L., "The Role of Universities in Training Nuclear Facility Personnel", ANS Publication Papers Presented at the Symposium on Training of Nuclear Facility Personnel, Gatlinburg, TN. April 19-21, 1971 .

, "Developmen S. d Kim . an S , Levine , n Asymmetricaa H. f . o tS , l Multiple - Position Neutron Source (AMPNS) Method to Monitor The Criticalit a Degrade f o y d Reactor Core". Ann. Nucl. Energy, Vol, 12 . No. 10, pp. 517-533, 1985.

225 NONDESTRUCTIVE STUDIEN SI METALLURGY USING NEUTRONS

. DIMIV C Jozef Stefan Institute, Ljubljana, Yugoslavia

Abstract Nondestructive techniques and studies in metallurgy using the 2bO kW TRIGA reactor at the Jozet Stefan Institute are described. The techniques include neutron radiography including a high resolution radiographie method called microneutronography, neutron induced autoradiography including use ot solid state nuclear track detectors, textur d neutroan e n diffractiond an , small angle scattering ot neutron. The utility ot a low power research reactor in these studies is emphasized.

lase Ith nt twenty five years significant efforts have been devote developino t d g different nondestructive methods using neutrons from the research reactors for inspectio f internao n l distributio f elemento n alloysn i s , structure studien i s polycrystalline material d lonsan g range fluctuation f moleculaso magnetir o r c density in matter. The most useful methods wr.icn can be used in metallurgy in oraer to investigate all this phenomena are neutron radiography especially microneutronographic and neutron induced autoradiographic techniques , neutron diffraction and small angle scattering of neutrons.

1. Neutron radiography

In metallurgy one can speak of neutron radiography as a valuable non-destructive method, which can be placed along side the more familiar and well-developed X-ray and ^"-ray radiography. However, neutron radiography should not be regarded as a method competitive with X and ]^ray radiography, but has tc be considere additionan a s a d l radiographie method, which provides complementary somn andi ,e cases, unique information relativ otheo et r radiographie methods.

In general, there are two ways in which neutron radiography can be applied ^n metallurgy:

a nig s aA h. resolution neutron radiographie method, capabl f investigatino e g in a qualitative and quantitative Tanner the microstructures and composition of a metallurgical specimen. This techniqu s callei e d rracroneutronograpny.

a defectcscopi s bA . c method capabl f detectineo macroscopia n o g c seal0 various detrimental defecte objectth n i ss being investigated. Detailed reviewf o s thi e literatur se foun th b fiel n n i dca d e (1).

227 f thio sm ai reporo describt e s i Th t e mor n detaili e e microneutronographic technique together with neutron-induced autoradiograph ye use b whicn i dn ca h metallurgy very efficiently.

1.1. Principle f micronautronographso y

Microrieutronograph high-resolutioa s i y n radiographie metho r inspectiofo d n e internath f o l distributio f nighlo n y neutron-attenuating elementn i s alloys. The method can be used either for veiwing the-internal nicrostructare e samplith n r coulo e d possibl e applieb y a quantitativ n i d ee manneth r fo r determinatio e internath f o n l compositio a specime f no meany b n f m^crco s - densitometnc readings microneutronographn I . y applie veiwino t d e gth internal microstrjctjr n imagea s cotainei e y placinb d a specimang , uslually thin (from about 100 ^ur. and up to a few 1000 urn), in intimate contact w^th a suitable neutron image detecto d exposina collimate ran o t t i g d ceaf o m neutrons. The primary image represents the spatial variation in the intensit e transmitteth f o y d neutron beam owin o differengt t attenuation by the various phase in the specimen. Thus the chemical heterogeneity is reveale a variatio s a d n photographii n c density e microneutronograpTh . s i h then obtaine y enlarginb d e primarth g y imag e lighmeany th c e tf o s micrcsccD. The resolution of the neutron-imaging technique must be acequate to allow the observations of internal mcroheterecgeneities at useful magnification of the primary neutron radiograph from at least 5 x up to 103 x. Micro- neatronographic techniques can be eitner direct or indirect of whicn the latte e mucar r h less effective thae formerth n . Ofte s asei n d gadolinium converter (2,3,^,5).

For metallographic investigation t wouli s e desirablb d o resolvt e e structural details with dimensions down to a few microns or less. The parameters that essentially determine resolution are: tne angular divergence of the reutron bean, the thickness of tne specimen, the separation between tne specimen e converteth d d an betweean r e converteth n d filan r m emulsion e typf th ,o e converter material and tne intrinsic resolution of the photographic material. A resolutio achievee b n ca y usinf about m dno ^i g5 t "rack-etching techniques together with boron-10 converters.

1.2. Qualitativ d quantitativan e e application f micrcneutronographso n i y metallurgy

Microneutronography as a method for the examination cf microstructure in metallurgical samples has been applied to several cifferent metallographic problems e identificatio, th suc s a h f phaseo n s (3,^,5) detectioe th , f c n micro segregation (5) e determinatiotn , f homogeneito n f nixino y d tr.an ge observation of diffusion in metals (5). In all these experiments tre am was to detect the presence of strong neutron-absorbing element such as B, Cd, Rh, Gd, Eu or Pu. In these experiments the advantage of microneutronography over microradiography has been demonstrated. Very illustrative is the experiment (6) where the homogeneity of plutonium in uranium oxide fuels has been studied.

The aim of quantitative microneutronography is to determine the concentrations of strong neutron absorbing elements. Quantitative microneutronography can be applied either to obtain concentrations averaged over structural details scannine th aree if th no a g densitometee windoth f o w d throughouran e th t specimen thickness r concentratio,o a particula n i n r phase.

1.3- Neutron induced autoradiography

In metallurgies, studies, microneutronography ia s suitable method for the qualitative and quantitative investigations of the distribution of strong neutron-absorbing elements, especiall f ligho y t element Li), (B s. However, the metho s limites sensitiviti d it y b d d spaciaan y l resolution e minimuTn . m detectable concentration of boron in a Fe-phase 100 ^TI thick is about 1 wt % at a spatial resolution of about 10^m. On the other hand, boron can have a profound metallurgicae effecth n o t l propertie f variouo s s alloy a leve t sa l below 100 ppm, and is particularly important in some nuclear materials. At thiw concentratiolo s n levels microneutronograph t capablno s i f detectinyo e g the boron distributio microstructuresn i n . Boro s alsni o hardly detectable e electrobth y n microprobe e cpmplementar.Th y metho o microneutronographyt d , with^required sensitivity and spacial resolution for the determination of boron distribution neutron-induces i , d autoradiography casen I . s whera e specimen contains elements like B, Li or U, which by themself emit charged particles upon neutron absorption presence ,th f theseo e elemente b n ca s revealed without any intermediate converter screen directly by detection f reactioo n particles wit suitabla h e detector t shoulI . notee b d d that in this case collimatioth e f neutrono n o morn s ei srequired n thiI . s method the specimen to be examined is-polished and appropriate detector is placed against this surface. The autoradiograph represents the distribution on the surface that is in contact with the detector. As a detector of charged particles could be used various Solid State Nuclear Track Detectors (SS.MTD) where the track-etching technique is used (7). Neutron radiography in combination witsparkine th h ge mos techniquth t f o sensitiv e s founb wa eo t d e neutron imaging techniques (8). Recently gelatine as an image detection material was discovered (9) and the most superior technique based on a combinatio n autoradiographa f o n opticad an y l microscop s developedwa y .

The techniques based on SSTDs can be used for detection of alpha particles from the reactions: 170(n , cO ] V, l80(p , t* ) 15N and 15M(n,c<)12C or protons

229 from the 14 N(n,p)1 4C reaction . In this uay the determination of oxygen a^a nitroge accomplishede b n nca .

So far numerous investigations of boron segregation, ciffusio*1 anc determinatio s solubilityit f e influenco r th d , an f ooroo e n graie n n gro.vtr ard recrystall^zation nave Dee^ made us^ng neut^on-irdjced alpha-autoracio- grapry.

Texture arc neutror diffraction

The applicatio" of neutron diffraciton to -nagnetic structure determination and to certain crystal studies ^s .veil , neutron diffractio o structurt n e studie n polycrystallin^ s e materials i t I s rather obvious that the properties of polycrystalline Tiatenals dépens on tnej." structure e graiTh . n orientation distribution-texture-gives important information about this structur d influencean e e propertiesth f materialssc r exampleFo . , texture influences both the behaviour of pclycrystalli^e materials during therma r mechanicao l l treatren arisotrcpe th d ar t f variouo y s physical orope^s t n in materials.

Therefore, of particular use in the ruciear fiele are investigations of fuel elements and fuel tubes Neutrons are scattered on atomic nuclei and or electron nagnetic moments. In this way they differ considerably from X-eays anc elections Neutron texture studies are specially interesting because of the Io/v absorption of neutrons ^n most technically emportant materials (10,11).

e exper.mentaTh l principl e followingth s x e a :neutro n bea s scatterei m n e d the specimen and neutrons are registered at a chosen position corresponding ta giveo n Bragg reflection. Only specime s rotatei n n suci d a h/.a y thal al t the crystallographic planes of the chDsen type (h,k,lx are brought to the reflection position. The change in intensity registered is due to textures. Different experimental techniques are used in neutron diffraction measurrents f sheeo t textures e transmission-reflectioth , n technique sphericae th , l sample method and the back reflection method. The size of the specimen can be aoout 30cm3. This means that this method is especially useful in coarse grain material studies e specimee volumth Th . f o e e investigatenb than ca t d usirg neutron s usualli s y abou 0 time1 t s greater than tha e X-ratth useyr fo d method.

Texture studies form a part of studies of the polycrystal structure. To describe this structure not only the orientation of tne grain, but a^so its siz d shapean e mus knowne b t e mai.Th n reaso o perfonrt n e texture studies

230 is that these studies a oettelea o t d r understandin propertiee th f o g f o s technological important materials. These properties can be often changed and improved upo f meani n f producinso desiree th g d textur e knownear mann .I y cases the mecahnism of texture formation is not known ard existing texture teorieaccount no r mano d sfo t y experimental facts affecting texture formatier.

3. Small angle scatterin neutronf go s

When a well collimated bea-n of X-rays or neutrons is passed through finelv divided natena s founi t ldi e beattha e widts th increasei th trf o h r accouno d t of refraction and diffraction by the individual particles. This broadening of the incident beam by particles having linear dimensions several orders of magnitude greater thae incidenth n t wavelengh e contrasteb o t s i t d wite tn h coherent diffracted spectra associated wite variouth h s interplanar d_stances, of the order of a wavelenght, determined by the crystalline structure within the particles. From X-ray and neutron studies of small angle scattering much information has been obtained regarding the shape and size of submic^oscopic particles. The difference between both techniques being that owing to the much ^arger panetratio neutrof no n beamusualls i t comulative si th y e result of scattering by many particles which is observed, in contrast with the single scatterin easile th f ygo observed X-rays.

e casIth ne when large particle e observesar d having diamete e ordeth f ro f r o 1000 A it can be shown (12) that the total cross-section for small-angle scatterin s givei : by n, <£ g Sa

e particle e radiue coherenth th th f s whers o i i b t,B e scattering amplitude of the atoms in the particles and X is the neutron wave length. From th^s calculatee b equatio n ca e increaset i nth d de transmitte widtth f o h d beam, brought about by diffraction, which is given by

Therefore, the scattering at small angles or small scattering vectors wave th e s numberi ) — k yieldwher —^ - = k ek s= informatioQ ( Q n o n"* -* 271 longe range fluctuatio f moleculano magnetid an r c densit matern a i y r Fo . Q-range betwee e observen on o severa10"-t ~ 8 *" s 10 lfluctuatio n witi characteristic dimensions between several 100 to 1000 8. This concerns the

231 investigations of dislocations in cold worked metals, of precipitates and tieir growt alloyn i ha functio s sa f timeo n f clustero , s from radiation damage deffects f inhomogeneitie,o glassn i s y materials. Snail angle scattering is also relate o polymet d r molecule plastin i s c materials. Detailed reviews of these fields can be found in the literature (13,14,15).

Experiment s showsha n that this kin f woro d k doealwayt no s s require high neutron intensity. Even with only about 10 n/cm s scientifically relevant 2 resultobtainede b n ca s , Monochromatic neutron e obtainesar a nelica y b d l slit rotor wit a hwavelengh t resolution pi A n . 8 ofoV 6 = 0.1X = X, t 5a hole collimator leads the neutrons to the sample. Scattered intensity cculc be detected by one boron counter.

e neutroTh n small angle scattering apparatus coul e connecteb d d wite th h reactor by a neutron guide tube which transfer the neutron intensity within a certain angular range tnat exis te reacto ti rea o t rr a placcor r o t efa e ) fron e neutro awath n0 (5 y n source wier e rad_at^.oth e n backgrour * i"5)lo s ..i e characteristicaTi l wavelengh tV transmitte d through suc a tubh e depenas en the radius of curvature R, the width of t.ie tube d anc the oroperties cf tr.e wall material e mos.Th t favourable wall materia ~ depositeN s i l n flao d t glass mirrors.

e combinatioTh f neutrono n small angle scatterin diffusf o d an ge scattering, where elastic scattering betwee Brage th n g reflection non-ideaa r fo s l crystal is modulated by the short range distortions around impurity atoms (12), in combination with other methods (calorimetry, structure analysis, metallographic studies) is an ideal tool to investigate and understand phase diagrams of allovs short range order, precipitates in the two phase regions and kinetics cf their growth, host lattice impurity interaction from the distortion of tie lattice, etc.

References

1. Berger, H., Neutron Radiograpny, Elsevier, Amsterdam (1965)

2. Eppelsheirrer, D.S., Arment, M., Nature (London), 207 (1965), 69

3. Fahmy, A.A., Interaction of Radiatior with Solids, Plenur, Press, New Ytori« H967), 537

U. Rant. J., Copie, J., Dimic, V., Ilic, P., Proc. TRIGA Owners Conf., Pavia, Gulf. Energy and Environn . System Rep. T-7^3 (1972)

5. Ilic, R., Rant, J., Sirca, F., Radiography with neutrons (Proc. Conf. Lenden) B NES (1975) 139

232 6. Dahlke, L.W., Robkin, M., Nucl. Technol 12 (1971 )

7- Ilic, R., Najzer, M., Podgornik, A., Solid State Nuclear Track Detectors, Pergamon, Oxford (1980) 655

8. Ilic, R., Najzer, M., Nucl. Instr. Meth. 1980 (1981) 635

9- Ilic Humar, R. ,Najzer, M. , , Podgornik,M. Soli, A. , d State Nuclear TracK Detectors, Pergar.on, Oxford (1980 689

10. Öles, A., Szpunar, J., Sosnowska, I., Nukleonika 13 (1968) 171

11. Kleinstük, Tobischk, J., Krist. Tech. 3 (1968) 171

12. Weiss, R.J., Phys. Rev. 83 (1951) 379

13- Schmatz , "X-ra ,W. d Neutroan y n Scattering Studie n Disordereso d Crystals ' 1 in: Treatise on Materials Science and Technology 2 (1973) 105

T4. Schmatz, W., Springer, T., Schelten, J., Ibel, K., J.Apply. Crystallography 7 (19746 )9

15- Gerold, V., J.Apply. Crystallography 11 (1978) 376

16. Maier-Leibnitz, H., Springer, T., Reactor Sei. Techn. 17 (1963) 217

233 SELECTED PAPERS FRO SEMINAE MTH R ON APPLIED RESEARCH AND SERVICE ACTIVITIES FOR RESEARCH REACTOR OPERATIONS, COPENHAGEN, DENMARK, 9-13 SEPTEMBER 1985 USE SMALF SO L RESEARCH REACTORS

H. RAUCH, G. BADUREK, F. GRASS Atominstitut der Österreichischen Universitäten, Vienna, Austria

Abstract e characteristiTh c feature a smal f o sl research reacto r universitfo r y based researc e describedar h . e flexibilitTh e instrumentth e rathef o yth w d lo r an s radiation level a usefumak t i e l toor trainingfo l , education, for test measurements and as a domestic base for cooperation with high flux facilities. The existence of various supporting laboratories is an essential requirement for a fruitful use. The research done during the last two decades at our 250 kW TRIGA reacto s reviewei r d shortly e constraintTh . w lo a f o s neutron flux have stimulate e developmenth d w ne f o t experimental technique e fielth f activatioo dn i s n analysis, neutron optics, polarized neutron physics d small-anglan e scattering.

GENERAL REMARKS

s definu t eLe small reactor s suca s h havin a peag k neutron Thes. s eflu 10'- . reactor x.1 m c * e widespreaar s d oveworle th r d and in most cases were founded after the nuclear advent caused by the 1956 Geneva Conferenc e Peacefuth n o e l Use f Atomio s c Energy. Thus they hav w bee eno operation i n morr fo ne tha a 0 year2 nd an s careful re-examinatio f theio n r futur e e fairlseemb us e o t s y justi- fied. For many applications, the magnitude of the neutron flux is of an importance similar to that of the maximum energy of accelera- tor based physics t thera remarkablYe . s i e e - differencsi e th o t e tuation in high energy physics, because the technique of measure- ment and the characteristics of radiation are independent of the magnitude of the reactor flux. The high flexibility of the experi- mental setup at small reactors renders them a unique tool for student trainin d motivationan g e developmenth r w experifo ,ne f o t - mental technique d methodsan s r introducinfo , g nuclear methodn i s other research laboratories, in industry and medicine.

Certain research project e fullb n y ca srealize a smal t a dl reactor by a few people or even single-handed and that within the perio a thesi f o d s work, which takes abou years3 t n sucI . h cases the complete setup starting from the primary beam hole collimator n neutroi n physice irradiatioth r o s n facilit n activatioi y n ana- e overlookeb lysi n ca s y thesb d e people, wherea t higa s h flux faci- lities an experiment often degenerates to a measurement owing to the complexity of the installed instruments and the pressure on measuring time. Therefore researce th , h a smalwor t a kl reactor seems well adapte e needuniversita th a locaf o o ss t da l d basan y e fo a fruitfur l co-operation with mediu d higan mh flux facilities.

According to a very recent statistic made by the IAEA (1), 228 out of the 345 research reactors in operation around the world are

237 small reactors. Many of them are overloaded with experimental ac- tivities t useno t dsome bu ,effectivel ar e l whical s quitt i ha y e depressing considering thae integrateth t d flux tha s availabli t e at such reactors is often larger than that available for a measure- ment at a high flux facility, where the measuring time is always very limited.

From our point of view, the conditions for an effective use of a small research reactoe ar r s embedde*tha i e scientifi t th i t n i d c communit e nearbth f yo y uni- versities in order to have a strong academic motivation and a direct access to the student recourses, *that there is a well-equipped background of auxiliary laboratories to stimulat e developmenth e w techniquene f o t d methodsan s , *that there is good co-operation with a high flux facility, *tha e researcth t h progra s orientei m d withi e possibilitieth n f o s suc a hreacto r rathe e perfectionisr th tha n o n m neede t larga d e installations, *tha e operationath t s possibla l w cost lo e kep y makins eb ar sa t g f automatio e us c reacto d accesan r s control.

A scheme of the different cooperations needed for the effective use of a small research reactor is shown in Fig.1. As a domestic base for reactor-based research such reactors can contribute sub- stantiall e yscientifi th als o t o c outpu f higo t h flux centers.

The discussion about an upgrading of these reactors will be permanent, but it should be kept in mind that the neutron flux is e onle parameteth on y t no r describin e capabilitth g a reactor f o y . n increaseA d neutron flux often implies reduced flexibility. There- fore, consideration should als e giveb o o othet n r method- up f o s grading e installatio, th suc s a h f colo n d sources, ultra-cold neu- tron sources, beam focussing devices, low temperature irradiation facilities, spectrum shift devices, etc.

HIGH FLUX FACILITIES MFOTUM FLUX REACTORS Fundamental Standard Neutron Restore* Research Nuclear Technologie*

SMALL REACTOR • itjpporiing laboratories Training Ttst Etpertments Education

Fig.1: Integratio a smal f o nl reactocooperatios it o t r n partners

238 Beam Hole Experiments

Aroun worle th d d abou 0 TRIG7 t A reactorn operatioi e ar s n and, thereforeW TRIGk 0 A 25 reactoe activit r th ,ou t ra y shoul e quitb d e typical for research at a small reactor. Our reactor has been in operation since 1962 and it is intensively used for neutron beam hole experiments, activation analysis, in-core irradiatiod an n student training. Up till now 60 diploma and 75 doctoral thesis works have essentially been based on the beam hole and activation facilities mann I . y case w experimentane s l method d instrumentan s s have been developed, which have been transferre higo t d h flux faci- litie r joinfo s t experiments. Fig.2 show presene th s t beam-hole application that changes substantially within a period of about 3 years and the scope of co-operation with other institutions. Only a few examples of our activities can be given in this short summary.

m_

ILL GRENOBLE

FAST PNEUMATIC SYSTEM Actmtnn Anatna

30-Nevtnn Drpofaruatnn n r i T—

W TRIGk 0 A25 Mark-Ie th Fig.2f o I e reacto:Us Wien d i existinr an n g co-operations.

239 Neutron Radioagraphy

mose th t f o typica e on Thi ls i sapplication f smalo s l reactors and wil e treateb l d separately (2). Neutron radiograph- de e b n ca y vote o appliet d moro t s wel a des a lfundamenta l research e hav.W e investigated metallurgical problems such as the diffusion of hydro- n liquidi n d metalge an s s observin e differencth g f atomio e d an c molecular diffusion and the variable exchange rate of hydrogen at different molecular bindings (3,4). At present we are studying the distribution and assembling of ^He in metals by the decay of tri- tium doped into the sample.

Neutron Small-Angle Scattering

e studyinar e behavioe W th g f hydrogeo r n ni isotopee H d an s metals als y meanb o f small-anglo s e scattering e small-anglTh . e scattering camera (Fig.3 e nondispersiv bases th i ) n o d e arrangement of two perfect crystals first used in 1969 by Shull (5) for the ob- servation of the single slit diffraction pattern. Our instrument is equipped with monolithic channel crystal ) increasin(6 s angulae th g r resolutio e dynamicath o t n l diffraction widt f perfeco h t crystals

2X2N b c 2 sec of arc B IT sin 2 0 (O B

e coherenth whers i t eb scatterin e particlgth lengtN d e an hden - sity of the crystal, A is the wave length and Og the Bragg-angle of the neutron. Fig.3 shows an example of such a measurement on a V-H system indicating the peak broadening in the $-phase, where hydride precipitates exist (7). For such an arrangement the angular or momentum resolution is strongly decoupled from the angular diver- beae th gencm d crosan y s sectioe incidenth f o n t beam, achieving e availabl n efficienth a f o e e us tneutro n flux. Real-time experiments are in preparation.

too

SAMPLE

THERMOSTAT CHANNEL CRYSTALS

DETECTOR

Fig.3: e perfecSchemth f o et crystal neutron small-angle scattering camera and characteristical results for a V-H sample.

240 Maintainin decoupline th g angulae th f o gr resolution froe th m beam widths resolutioe th , s recentlnwa y increased w furthefe a y rb order f magnitudo s y usin b ee centra th g l pea f multiplo k e Laue rocking curves, whose width e give ar sy -(8,9 b n )

hkl 60. 0.705 c ar f o 0.00 c 2se (2) e latticth s i wher ei ^ distanc, d ee reflectin th f o e s i g t plan d an e e thicknesth e crystath f o sl plates. Related measurements have been made using monolithic designed multi-plate systems at the high flux reactor at Grenoble, but they are also feasible for small reactors.

Total Reflection and Grating Diffraction

These phenomena are based on the index of refraction (n = 1-b /(2irN X )^ 1-10~^ havd )an e been widel cone yth -user fo d structio f neutroo n n guide tubes (10,11 o transfet ) e neutrorth n intensity fro vicinite e reactoth m th f o yr placa cor r awao t efa e y (^ 100 m) , where the radiation background is low and more measuring position e installedb n ca s n thi.I s fiel e havw d e investigatee th d properties of curves totally reflecting Soller slits (12) subsequent- ly combined with focussing devices (13).

The experience gained on measuring the small angles of total reflection were useful for the observation of neutron diffraction at ruled gratings (14,15). Fig .4 show a characteristis c resulf o t suc measuremena h t performed wit a hrule d grating havin a glattic e constant a = 18.5 urn. These findings have certainly stimulated other groups to measure the grating diffraction with ultra-cold neutrons (16 d hav)an e influence developmene th d e so-calleth f o t d super- mirrors (17 r layereo ) d mirrors (18), which hav verticaa e l periodic structur d extenan e e regioth d f totao n l reflectio a facto y nb f o r 2-3.

•no

so

Fig.4: Observed diffraction pattern at a ruled grating f Be-filtereo d cold (above) f thermao d an l (below) 20 30 to 50 anyit diffractionof [•] neutrons.

241 Neutron Interferometry

There is a strong motivation to develop interferometric measure- ing methods, since they make macroscopic coherence measurements feasible r neutron W Fo .reactok 0 e succeeden 25 w 197si r r 4ou t a d with a setup shown in Fig.5 (19). A monolithic perfect silicon crystal provide e macroscopith s c coherenc e latticth f o ee planes throughou whole th t e crystal s a lengtwhic It s . f ha abouho h cm 7 t actio n easilca n e understoob y d fros analogit m o opticat y l inter- ferometry. According to dynamical diffraction theory the following relations hold for the intensities and for the wave functions, e.g. (20):

11,2 Jö l (3)

where wave arth ee function n forwari s d direction behind e interferometeth r e beacause, respectivelyth II m y d pathb d an I s . A phase shift produced by a sample of the thickness D

.II -iXb cND (A)

causes an intensity modulation 2 = 2 (1 + cosb NAD) (5) U c

After this technique had been installed at the high flux reactor at Grenoble, its use became widespread in many laboratories all over the world e techniquTh . s appliei e n fundamentali d , nuclea d solian r d state physics. The first verification of the Air-symmetry of spinor wave functions (21-23) e gravitationa,th l phase shift measurements (2A,25) e spi,th n superposition experimen macroscopia n o t c scale (26) and accurate determinations of neutron scattering lengths (27 - 29).

IÎKU«« 3

Y QffAPHlTf ( «JWOWOWC• W. .. . • . . .< rV8-." < 2 dtnoltd - btam (H) & \ JL-»«Smirror f forward btom- 10) : . - .'/."• .*• ' rf« (^ Si-CRYSTAL £

SAMPLE 1

\ \" I *HI/ l • , ,W...1 I I . 4....J. . 1 1 - i -

Fig.5: Schem f perfeco e t crystal interferometry (left), sketcf o h the first test arrangement (middle d firs)an t observed inter- ference fringes (right).

242 a retrospectiv n I e vie e feew s verl wa tha yt i timportan o t t start this interferometer projec a smal t a tl reactor because ew first had great problems in operating the neutron interferometer at the high flux reactor at Grenoble. We were not able to observed any neutron interferences there, althoug e detectew h d X-ray interferences n boti h Wie d Grenoblean n . Most unexpectedly t turnei , t thaou d t these difficulties were due to very low frequency vibrations of the whole building caused by the heavy-water pumps for the reactor. These vibrations statistically shifted the whole interferometer crystal during the time of flight (^ 30 (as) of the neutrons through the inter- ferometer over a distance of about one lattice constant. Had we start- e hig r studth eh ou d t a fluy x facility froe outsetth m e migh,w t very well have publishe n articla d e stating that perfect crystal inter- ferometry cannot be realized.

Polarized Neutrons

Already fifteen years ago electronic chopping of a continuous polarized neutron beam into short and discrete intensity bursts has been accomplishe e firsth tr r institut ou fo dtim t a e y meanb e f o s pulsed high-frequency spin-flip systems (30). A further improvement of this technique could be achieved later on by the development of a fast DC-coil spin-flip chopper (31), which allows to produce neu- tron pulses of less than 5 p.s duration and correspondingly high re- petition rate. Suc n advancea h d chopper system includin cons it g - trol instrumentation has been installed by us at the diffuse scatter- ing spectrometer D7 at the high flux reactor of the ILL Grenoble, o (32)to . Apart fros unprecedenteit m d time resolutio probablt i n y represent e mosth st flexible time-of-flight facility tha s presenti t - ly in operation. Without any change of the experimental setup it is capabl o operatt e e eithe a conventiona n i r l periodia pseudo n i r -o c stochastic correlation time-of-flight mode (33) with several options concerning the correlation sequence length and the suppression of e elastith c pea y digitab k l filtering.

A further technique involving polarized neutron beams that we e regularlus e r purposreactoth ou t r a f ysolid-statfo o er e research is the neutron depolarization on passage through magnetic materials. Since about the mid-sixties we have applied this technique for study- in a gserie f magnetio s c phenomen magnetis a c phase transitions (34) or the formation of flux line lattices within superconductors (35). Recentl developmene th y d installatioan t w timne ea resolvinf o n g three-dimensional neutron-depolarization facility has been completed r institutou t a e which allow o recort s e l changthreth al d f eo e spatial component neutroe th f o sn polarization s passagvectoit n o re throug e sampl a th functioh s a e f timo n e relativ e momenth t o a t e whic n externaa h l magnetizing fiel s suddenli d y removed (36). With this real-time experiment magnetic relaxation effects with charac- teristic time constants between about 1 ms and several hours can be studied over a sample temperature range from 4.2 K to 300 K. As an example of such a measurement, Fig.6 shows the slow magnetic acco- modatio a superparamagneti f o n c Cu-1%Co single crystal withia n field of 0.6 ml after it had been exposed during 40 ms to a field of 179 mT in the opposite direction. The quantity D is one of the diagonal elements of the so-called depolarization matrix D that re- lates the incident and final polarization by Pf = D P^. From this

243 10f_ Cu-r/.co

G B 6 of = t OS" VA: T-320K

06 Fig.6: Magnetic after-effect ia nsuperparamagne t 04 studie y neutrob d n . depolarization. • " -*t 02 '. •/• *

"A..*» T= 200 K o =- l -01 10 100 100] 0Is

knowledge information abou magnetie th t c domain parametere th f o s sample can be gained (37). Presently our neutron depolarization in- strument is used to study magnetic percolation phenomena within Co- , Ga alloysric o C h . * x 1- x

Neutron Dif f ractometry

Whereas inelastic neutron scattering experiments cannot reason- abl e donb y e W reactor witk r smal 0 ou h 25 l , diffraction experiments r crystafo l structure experiments have been performed successfully. e availablth e us eo T neutron flux very effectively e hav,w e installed a FOURIER time-of-f ractometelighf f di t rwhic, s particularli h y useful for polycrystalline or powdered specimens (38) . These specimens are illuminated by a polychromatic beam. Then, according to Bragg's equa- tion, the intensity scattered into a given direction contains a dis- crete number of wave lengths which correspond to the individual lattice planes. Instead of measuring the neutron time-of-f light and henc wave th ee length conventionall y meanmechanicaa b y f o s l single slit choppe e measurw r e FOURIEth e R transfor e time-of-th f o m f light distribution. This is accomplished by means of a chopper disk with 540 slits and an equivalent stator in combination with a phase-sen- sitive neutron registration system (39). From the measured amplitude neutroe d phasth an f o en intensity modulatio n equidistana t a n t mesh of frequencies (fkHz0 9 time-of-e ma )^ xth f light spectrue b n ca m calculated by means of FOURIER inversion. Another possibility would n on-lina e b e synthesi e so-calle y meanth b s f o s d "inverse" FOURIER method used by the Finnish group (40) . The advantage of the FOURIER method compared to conventional time-of-f light spectroscopy is the much higher duty-cycle of the chopper (50% vs M%) and the total de- couplin e achievablth f o g e tim e/f1 resolutio± maxC )• frot e (A th mn available beam cross section n exampla s e diffractioA . th e n pattern oa polycrystallinf e Nb-sampl s showi e n Figi n whic, .7 e obtainew h d with our dif f ractometer after a measuring time of 8 hours.

244 WAVELENGTH [A] 1 2 ————I——————i—————

'500 b POLYCRYSTAN L REACTOR ce POWER: 250 kW £,000 Fig.7: Diffraction pattern oa polycrystallinf e to Nb-saraple measured wite FOURIEth h R o o tirae-of-flight spec- trometer .

tooo 2000 3000 — TIME-OF-FLIGHT [ps]

SHORT TIME ACTIVATION ANALYSIS

Short time activation analysis (AA) has proved to be a valuable e determinatioth toor fo l f elemento n se activate b whic n ca h o t d short-lived nuclide r isomerio s c states n internationaA . l workshop held at our institute was devoted to this subject in February 1980. The published results (41) represent the state of the art at that time.

As a neutron source, we have a TRIGA reactor which allows up to 6 pulses per hour of the same peak power. Thus we can apply the reactor pulses for activating samples, a method which was first pro- pose y Lukenb d s (42,43) .e exceptiona Owinth o t g l difficultie- en s countered in the measurement of very high count rates, however, no actual analysis was published until 1970, when a decay analysis of s Ge-71m th0 2 n eiroi m n meteorite s performewa s d (44).

e morth Wore n physicao k l aspect f short-liveo s d isomeric states has been performed at our institute since 1963, when Hübner (45) buil a simplt e fast pneumatic tube system wit a samplh e transporta- rom_irradiatiof tios m n0 5 tim f o e measurino t n g positione .Th activation enhancement A, i.e. the ratio of activity induced by pulse activatio e saturatioth d an n n activit = Nn stationari a A y y acti- vation is:

A = = Xe~ expUt A/ 70)Vt- f ( 2'}dt- ';

T -1/2 a = -r-ln 2 (6)

The increase in activity depends on the full width half maximum T, r reactorou t a .s m Wit 8 whicmaximur 2 hou s i h m peaW M k0 powe30 f o r the enhancement factor is 1200. According to this equation, the sen- sitivity enhancement dependhale th e factivate n th o slif f o e d species. For the 20 ms nuclides Na-24m and B-12 the factor is 640, for Cl-38m, Li-8, Zr-9 d He-6(Be0an t a d drop1 an t takeo ) i t 0 valu e s3 th sf o e 26 s half life. The reason why pulse activation is atractive follows from the approximation A^/A2 = A<^ /Aco'to''11» which holds with a maxi-

245 n irradiatioa r fo m % erro5 mu f n o o 0.1 rf ^2t i tim >p ^ 5^]'u eT interesting activity A, is obscured by a background activity A2, the activity ratio A«/A2 being inversely proportiona e correspondth o t l - haling f activatiolivesthe if , n cross sectio equalis n . This favours the activation of short-lived species, an advantage which is lost during prolonged activation. Cycli A (46-48A c ) offer n alternativa s e to pulse activation, if the activation time is short enough, but has e greath t disadvantage thae backgrounth t d increases witnumbee th h r of cycles.

In the irradiation position of the present fast pneumatic tube system (49) our reactor yields 1.3x 10 s~'cm~^ neutrons. To account e fasth t r varyinfo g high counting rat a high-resolutioe n high-rate y-spectroscopy system with a close sample detector geometry has been developed (50,51).

Fig.8 shows the results obtained by pulse activation of NBS- SRM-1571. Triggering the pulse rod starts the time channel, so that the complete histor f irradiatioo y d transportatioan n s recordei n d together with the decay curve. The vast amount of information avail-

DICAVCUItVI CIH4KK/CN

Fig.8: Ge(Li)-spectra (1) - (7) and decay curve (8) of Cerenkov- counting after a 2$-pulse activation of NBS-RSM-1571 ORCHARD LEAVES. Experimental conditions: (1) Decay TjLme 0.04, Collect- ing Time 0.2 [s]; (2) DT 0.24, CT 2;~(3) DT 2.24, CT 2; (4) DT 4.24, CT 20; (5) DT 56, CT 20; (6) DT 76, CT 200; T 275D 200T ) C ,) Deca(7 (8 ; y Curv ms/Channel4 e .

246 able within a short time by this method renders data reduction imper- ative. Schindler has written the highly efficient program ALCHEM (52) to extract the data from y~sPectra. The decay curves are ana- lyzed by RINAA (53), a program developed by Schmidt which delivers a numbe statisticaof r lcorrectnes the test decafor sthe y of sana - lysis .

In order to utilize the maximum flux of the reactor, Salahi (54) constructed a He-driven irradiation facility with a 14 MeV "LiD neu- tron converter for insertion into the central thimble of the reactor which is now in cold test state. Sample management and irradiation processin s providei g a micro-processor y db , photosensors, magnetic valves, optical encoders and a revolving station. The transfer time for this system will be 30 ms and (n,2n) reaction may render possible.

CONCLUDING REMARKS

The preceding sections deal with characteristic results demon- strating an effective use of the available neutron flux and discuss some selected research field s e treateb whic a smaln t ca ha d l reactor. Only measurements performe r smalou lt a dresearc h reactor have been included and these demonstrate that a small reactor is well suited for a variety of research projects. New measuring techniques and methods have been developed which were later also installed at high flux facilities and are now being used for joint projects.

Future efforts should not only be concerned with increasing the primary source strengt t alsbu ho with providin mora g e effective us e of the available neutron flux. Therefore, the development of advanced neutron focussin w detectogne systemf o rd an devices s should receive the same priority. Compared to light and charged particle optics the guid d focussinan e g techniqu r neutronfo e beginnings s stilit i s n i l . The upgrading of a small research reactor should not only focus on e intensityth t rathen optima,bu a n o r l neutron beam tailoring system, which shifts the neutron intensity to a certain energy, angular or space intervals with .certain polarizatio r phaso n e propertier so with a distinct time structure. Upgrading of a small reactor should neither be at the expense of flexibility of research nor substantial- ly increase operational costs, and must guarantee a low radiation level.

In the future small, medium and high-flux facilities should be treate n integratea s a d d system establishin a propeg r divisiof o n research, industrial development, trainin d educationan g . Suca h system would contribute substantiall e scientifith o t y c standarf o d e entir e countrth o that th f o etd an scientifiy c community.

e continuouTh s e personne supporr reactoth ou l f al o t r lf o staf d an f of the institute is gratefully acknowledged.

REFERENCES

. Muranaka1R . , IAEA DOC.No, SepP 8 .59 . 1983. . DomannJ . BartonJ . d 2 an s , this meeting.

247 . ChountaK . RauchH . 3 mkerne 4 o d (1968)t 44 an s, A , n13 .e^r e gi

. Zeilinger. RaucA H d . an h4 , Atomic E^nergy_Revj 9 (1977)24 , Le15 w. 5. C.G. Shull, Phys. Rev. 179, 752 (1969). . Hart. BonsM U d . ,an e6 Appl_. _Pjv 8 (1965). .Let_tys 23 , 7 ^ . 7. D. Bader, H. Rauch and A. Zeilinger, _Z^_Nat_urf. 37a, 512 (1982). 8. U. Bonse, W. Graeff and H. Rauch, Phys.JLett. 69A, 420 (1979). . RauchH . 9 Kischko. ,U . Petraschec,D . BonseU d . Physan ,Z k . (1983)1 B511 , . —————— 10. Maier-LeibnitH . . SpringerT d zan , Reactor Sei.7 Te^hn21 , 17 . (1963). 11. ILL Neutron_Be^am Facilities, Grenoble 1974. 12. W. Fiala and H. Rauch, Nucl. Instr. Meth. 52, 15 (1967). 13. M. Friedmann and H. Rauch, Nucl. Instr. Meth. 86, 55 (1970). . Rauch H 14. Kur H d . . Physan zZ , . 220 5 (1969),41 . 15. A. Graf, H. Rauch and T. Stern, Atomke rnenerg_ie 33, 298 (1979).

16. H. Scheckenhof er, A. Steyerl, PhyS|A^Rev -_Let t^. 39, 1310 (1977). 17. F. Mezei and P.A. Dagleish, Comrau^Phy^s^ 2, 41 (1977). 18. A.M. Saxena and B.P. Schoenborn, Ac_t£ Cryst. A33, 805 (1977). 19. RauchH . . Treime,W . Bonse U d an ,r Phys_^_Lett_._ A47 9 (1974),36 . . RaucH . BonsU d h. an e o_n_Interferometry20 (Ed.)r t u e ,N , Clarendon Press, Oxford 1979. 21. H. Rauch, A. Zeilinger, G. Badurek, A. Wilfing, W. Bauspiess and U. Bonse, Phys. Lett. 54A 5 (1975),42 . 22. S.A. Werner, R. Colella, A.W. Overhauser and C.F. Eagen, Phys. Rev. Lett. 35, 1053 (1975).

. RauchH . . WilfingA ,23 . BauspiesW , . BonseU d an ,s _Z._PhysJL B89, 281 (1978). 24. R. Colella, A.W. Overhauser and S.A. Werner, Phys. Rev. Lett^ 34, 1472 (1975). 25. J.L. Staudenmann, S.A. Werner, R. Colella and A.W. Overhauser, Phys. Rev. A21, 1419 (1980). 26. J. Summhammer, G. Badurek, H. Rauch and A. Zeilinger, Phys. Rev^ A27, 2523 (1983). 27. W. Bauspiess, U. Bonse and H. Rauch, Nucl^Jtostr. Meth. 157, 495 (1978). . KaiserH . . 28 RauchH , . BadurekG , . BauspiesW , . BonseU d an s, Z. Phys. A291, 231 (1979). . R.E29 . Word S.Aan d . Werner, Phys. Rev. B26, 4190 (1982). 30. H. Rauch, J. Harms and H. Moldaschl, Nucl. Instr. Meth. 58, 261 (1968). 31. BadurekG . , Nucl. Instr. Meth. 189 3 (1981)54 , . . BadurekG . 32 , Institut Laue-Langevin Report, 78BA377T, Grenoble (1978).

248 33. L. Pal, N. Kroo, F. Szlavik and I. Vizi, Proc. Conf. on Neutron Inelastic Scattering, Copenhagen, Vol. 2 (IAEA Wien, 1969) p. 407. 34. H. Rauch and E. Löffler, Z. Phyjs. 210, 265 (1968). 35. H. Rauch and H.W. Weber, Phys. Lett. 261, 460 (1968). . Badure. JaneschitzG G d . an 36 k , submitte Nuclo t d . Instr. Meth. 37. M.Th. Rekveldt, Z. Phys. 259, 391 (1973). . BadurekG . 38 , G.P. Westpha . ZieglerP d an l , Atomlcernenergi, 29 e 27 (1977). 39. A. Virjo, Nucl. Instr. Meth. 73, 189 (1969). . HiismäkiP . 40 . Virjo A . Pöyr ,H d an ,y Nucl. Instr. Meth. 1261 ,42 (1975). 41. First International Worksho n Activatioo p n Analysis with Short- Lived Nuclides Radioanal. ,J 2 (1981- . 1. ) ChemNo , 61 . 42. H.R. Lukens, J. Radioanal. Chem. 1, 349 (1968). . H.R43 . Lukens, H.P. YulV.Pd an e. Guinn A 5702G , , General Atomic Report (1964 d Nucl)an . Ins_tr 3 (1965)^ 27 Meth , .33 . 44. 0. Brandstätter, F. Girsig, F. Grass, R. Klenk and R. Bauer, Atomkernenergie 15, 285 (1970). 45. K. Hübner, Atomkernenergit; 10, 196 (1965). 46. W.W. Givens, W.R. Mills, jr. and R.L. Cadwell, Modern Trends in Activation Analysis ,4 (1969) Vol92 , .2 . 47. A. Golanski, J. Radij3ana 1. Chem. 3, 161 (1969). . SpyrouN . Radioanal. 48 J , . Chem 1 (1980).6 . . Brandstädter0 . 49 Girsig. F , Klenk. R Gras. F ,d an ,s Nucl. Instr. Meth. 104 5 (1972),4 . 50. G.P. Westphal, J. Radioanal. Chem. 70, 387 (1982). 51. F. Grass, J. Radioanal. Chem. 70, 411 (1982). 52. P. Schindler, AIAU 82505, Atominstitut Wien (1982). 53. J.O. Schmidt, AIAU 83510, Atominstitut Wien (1983). . SalahiA . . Grass54 F , . BenschF , . Zugare,G d J.Okan . Schmidt, Proc. Int. Top. Meeting on Irradiation Technology, Grenoble, France (1982).

249 TESTING OF POWER REACTOR FUEL TYPES IN THE DR3 REACTOR AT RIS0

. KNUDSEP N Metallurgy Department, Rise National Laboratory, Roskilde

I. MISFELDT Advanced Engineering Division, Atlas-Danmark AS, Ballerup Denmark

Abstract From the beginning of the Danish Fuels Development Program/ it has been important to test U02~Zr fuel pins under realistic conditions, i.e. at temperature and coolant conditions as in a power reactor. This is possible with the high-pressure rigs simulating BWR and PWR conditions. More tha 0 tes20 n t fuel pins hav w beeeno n irradiateo t 3 DR n i d burnups up to 70,000 MWD/tU. This program comprises standard R designsPW d an , R advanceBW d fuel designs suc s LOWa h I (low interaction), i.e. a special duplex pellet, power ramp test t significana s t burnup levels etc. Significant use of the DR3 facilities is also being made in the current, internationally sponsored RIS0 Transient Fission Gas Release Project, wit e objectivth h o studt e e kineticth y f o s fission gas release in high-burnup fuel. Segments from pre- viously irradiated UC^-Zr fuel pine refabricatear s e th n i d hot cell d mountesan d with pressure transducers. During tran- sien 3 reactot DR testin e RIS0t th a r n e changi g,th n interi e - nal pin pressure is monitored continuously. Before and after the transient testing, the fuel is characterized extensively in t thcells ho esupplemena s ,a observatione th o t s durine th g irradiation. The pressure transducer of a test fuel pin is connected to a fully computerized measuring and data acquisition system. This system allows measuring of power and pressure in the experi- ments with high accuracy. Techniques have been developed for the derivation of gas release in fractions of the produced fissio wits ga n h overall accuracies bettega e th r f o tha % 1 n inventory. Releases down to 0.1% can be followed with a reso- lutio n timi nf leso e s tha 1 minuten . The DR3 facilities are well suited for both general fuel per- formance evaluation and special projects, because they are simple in design and reliable in operation. Also, the DR3 reactor and RIS0's Metallurgy Department, including the hot cells, are close to each other. This enables a quick feedback of test results as input to the planning of new investigations.

251 1. INTRODUCTION Fuel testing is an important part of the Danish fuels develop- ment program. Consequently, facilities have been developed that permit testin f U0o g 3 2reacto-ZDR r e t fuelRISth a r n 0i s under realistic conditions simulating thos BWRf eo PWRsd san . These facilitie e alsar s o being use n internationalli d y sponsored projects. The present paper gives a brief summary of the Danish fuels associatee prograth d an m3 facilitiesDR d . Example e prear s - e investigationsenteth f o d s performed. Finally n overvie,a s i w three giveth f eo n RIS0 project o studst y fissio s releasga n e behavio f wateo r r reactor fuels.

E DANISTH . H2 FUELS DEVELOPMENT PROGRAM The objective of the Danish fuels development program, managed by RIS0's Metallurgy Department, is to establish and maintain a national expertise in fuel design, manufacturing and per- formance evaluation. This expertis s availabli e o Danist e h authorities, utilities and industry. The program, based mainly on U02~Zr fuels and LWR type, comprises: projectD Join & R t selecten i s d areas with industrd an y utilities Collaboration arrangements with foreign organizations Managemen d executioan t f internationallo n y sponsore& R d D projects Transfer of commercial activity to industry.

Major results achieve r includefa o s d : (a) Irradiation in the OECD Halden Reactor of 10 fuel elements ta o(current ) maximum burnu f 43,00o p 0 MWD/tU. (b) Irradiation of 4 fuel elements to 20,000 MWD/tU in the Kahl reactor. (c) Irradiatio f moro n e tha0 tes20 n t fuee l th pin n i s 3 facilitiereactorDR e th .n i sBurnu o 70,00t p u p 0 MWD/tU have been achieved. This subprogram comprises standard BWR R fueanPW d l designs, advanced designs suc LOWs ha I (see below), ramp test t significansa t burnup levels, fission gas release studies in steady state and transient conditions, etc. ) Executio(d o internationatw f o n l projects, d preparationan s fo a thirr d one n ,fissioo s releasga n t higa e h burnup. (e) Development of Danish fuel performance codes for the planning and evaluation of the fuel irradiations.

252 (f) Settin f U-Ao p u 1g fuel fabricatio3 reactoDR e n th i r r fo n collaboration with Atlas-Danmark's Advanced Engineering Division. This compan w manufactureno y e currentth s , highly enriched DR3 driver fuel elements and studies manufacturing methods for lower enriched fuel types. Outsid e nationath e l program, valuable experienc s gainei e d from examination in the RIS0 hot cells, under special con- tracts f foreigo , n water reactor fuels.

3. FUEL TESTING FACILITIES AT RIS0 3.1. Equipment in DR3 The DR3 reactor is a 10 MW heavy-water moderated and cooled materials testing reactor. It is used extensively for fuel testing, physics and materials experiments, and isotope pro- ductions. The fuel testing facilities are located in the hollow driver elements, wher e unperturbeth e d thermal neutron flu s 8.8-1.i x 5 x 1014 n/cm^ sec. The fast neutron flux is 2-6 x lO^^ n/cm^ sec, including contribution from the fission in the test fuel pin. e irradiatioTh drivee m holec nth 5 rig n placese i e r sar th n di fuel elements which have a fuelled length of 60 cm. There is e lon r on severao g l shorter test fuel pin n eaci s h rige Th . test fuel pin is cooled by natural convection of the primary rig water guided by a riser tube. The primary water is pres- surized, e.g. to 70 or 100 bar, to simulate BWR or PWR condi- tions. The primary flow is reversed in the annulus outside the riser tube wher heae transferres eth i t d throug e Zircaloth h y pressure vesse le secondar th wal o t l y (light-water) coolant flow. The rigs are connected to out-pile control, pressurizing and cleaning circuits .A smal l flow, abou cm-^/sec1 t prie th -f ,o mary coolan s circulatei t d pas a tradiatio n detectord an , througn exchangeio a conductivitn a hd an r y meter e circuiTh . t is pressurized from a helium bottle. The out-pile circuit is shielded, so it is possible to operate with a failed fuel pin. e heaTh t outpus determinei g tri fro e e y meanb th th dm f o s measured flod temperaturan w e difference between inled an t outlet of the secondary coolant. The heat load of the fuel pin is foun y correctinb d poweg r ri g gamm fo ri re th e ga th hea n i t and fuel materials (Ref. l). The principle of the rig design is illustrated in Fig. 1. Further details about the rigs and out- pile system foune b Refn n i dsca . 2 normae Th l operatio 2 day1/ s3 2 followe s ni perio3 a y DR db f do shutdow2 day maintenancr 1/ sfo 4 f exchangr no fo d ean fuef eo l and experiments. Each test fuel pin is suspended on a lifting rod from the rig top flange. During the reactor shutdown, the rig top flange can easily be unscrewed and the test fuel as- sembly exchanged when desirable.

253 Ihimbl«

Coolin (1ew g r |»C«t

tircclojr-2 prvttur« vttitl

lu»l rod —^ guid* tub«

HP1, mk III (Zircaloy I v«i«»l 150 bar« pr«t« art)

low prctiur« cooling w• t *r

* r•••—p i u r I*d wa

1 FigPrincipl. f Fueo e l Irradiatiog Ri n

Some of the test fuel pins have been instrumented with central fuel thermocouple d witan s h fuel stack elongation detectorsn I . the fission gas release studies, important use is being made of a computerized pressure measuring system attached to high- burnup fuel pins as explained in section 5.2. 3.2. Hot Cell Examinations It is important that fuel performance tests in the reactor are followe y extensivb d e hotcell examinations e selectio.Th f o n examination techniques will of course depend on the objective of the particular investigation. As an example, non-destructive (NDE) and destructive (NDE) and destructive (DE) examination techniques used in the RIS0 fission gas projects are tabled on the next page.

4. EXAMPLES OF FUEL PERFORMANCE TESTING e numerouth n I s fuel irradiation n DR3i s , various aspectf o s desig d operationaan n l parameters have been investigateds A . examples a specia, l pellet desig d soman n e power ramp tests will be mentioned briefly in this chapter. The following chap- ter gives an overview of the RIS0 fission gas projects. e LOWTh I4.1 . Pellet Design Failures of UO^-Zr fuel during power increases have necessi- tated constraint n reactoo s r operation A possibl. f o y wa e avoidin r reducino g g thes ef duple o constraint e us x e th s i s fuel where an enriched annulus surrounds a natural or depleted core. This leads to lower average fuel temperatures, especially early in life, and consequently to smaller clad stress for a

254 given power increase e Danisth n I .h LOWI (1.Q.W, interaction) duplex design there is a gap between the core and the annulus, see Fig. 2. This prevents the propagation of of fuel cracks and hence reduces stress concentratio e clath dt a ninne r surface. Features of the LOWI design were examined in DR3 irradiations. LOWI and standard fuel pins were irradiated at similar heat load f abou o se standar0 W/cmth 65 t r Fo .d pin, this resulten i d pronounced formatio f columnano r grain a centra d an s l voin i d the pellets, indicating a center temperature of about 2300°C. The LOWI pin, on the other hand, had very little, if any, fuel grain growth, indicating thae centeth t r temperaturt no d di e exceed about 1400°C e significan.Th t differenc n fuei e l tem- perature s alswa so reflecte n claddini d g diameter difference, e Figse 3 .(Ref . 3) .

Fig. 2. LOWI Pellet Design.

dWvvl

pre 25 22 post '9 16 13

25 22 post 19 16 .13 K10

Fig Pre- and Post-Irradiation Profilometry of Standard and LOWI Pellet Fuel Pins.

255 T CELHO L TECHNIQUESE TH USE N I D RIS0 FISSION GAS PROJECTS

NDE Technique Observation

Axial gamma scanning Local, relative power and burnup Profilometry Diameter changes Eddy-current testing Cladding integrity and visual examination Neutron radiography Fuel structure, fuel column integrity Plenum spectrometry Fissio s contenga n t

E TechniquD e Observation

Punctur ing Fission gas analysis of whole pin Retained gas measurement Fission gas content of pellet size samples Electron microprobe Diametral Ze and Cs distribution analysis (EPMA) Micro gamma scanning Diametral Zr-95 and Cs-137 distribution Ceramography with quanti- Fuel structure, especially pore tative image analysis size distributio d graian n n size Burnu d heavan p y isotope Burnup; basis for calc. of fission analysis gas generated

4.2. Power Ramp Testing The fuel irradiation facilities in DR3 are well suited for power ramp testing since the power history of each fuel pin is monitored continuously, durin e base-irradiatioth g o signi(t n - ficant burnup) as well as the transient testing itself. Furthermore n easilca a ,fuee n unloade b ypi l d durin a reactog r shutdow d transferrean n e hotcellth o r t interid fo s m examina- tion, e.g. after the base-irradiation.

256 e testh On tf 3 compriseo eserie DR n i s d three set f shoro s t PWR-type fuel pins that were transient tested at approximately JO,000, 20,00 d 30,00an 0 0 MWD/tU, respectively. 6) (Refs - 4 . Fast power increases, about 20 W/cm.min, were employed with the first two pin sets, resulting in several cladding failures. For the last set, a slower approach (about 4 W/cm.h), enabled pin survival and subsequent fission gas release determination by puncturin othed an g r technique e hotcellsth n i s . These power ramp tests wer e publishee firsb th e o t t r PWfo d R fuel pinse claddinTh . g failures were typical stress-corrosion type cracks, that were axially very short (one or a few wall thicknesses t alwayno d san ) connecte e claddinth o t d g inner surfacl planeal n i f eobservation o s date Th a. froe lasth m t set of fuel pin were used as the experimental basis in a com- parison of a large number of fuel performance codes, organized e IAEAbth y .

5. FISSION GAS RELEASE STUDIES The design to improve fuel utilization has created a growing interes n extendini t e burnuth g f LWo p R a fuelresult s A . , fuel performance date needear a t a burnud p levels wel n excesi l f o s 30,000 MWD/tU. Fission gas release is one of the important factors, especially for power increases (transients) late in life, because even moderate increases can then lead to im- portant releases. The combinatio a numbe f o n f capabilitieo r s relate o fuet d l performance testing have enabled RIS o executt 0 e several inter- nationally sponsored projects to study the various aspects of fission gas release in UC»2 fuel at high burnup. These capabili- ties include e fueth : l testing facilitie t DR3a s , including unique instrumentatio r internafo n n pressurpi l e measurement; many specialized hot cell techniques; long experience in fuel performance evaluatio d managemenan n f o largt e projectse Th . following sections giv a briee f overvie f eaco w f theso h e RIS0 projects. 5.1. The RIS0 Fission Gas Project (1980 - 81) The transient tests in this project were performed with fuel pins that had been base-irradiated to 27,000 - 36,000 MWD/tU at fairly low power levels and then tested to peak pellet powers W/cm0 44 - . 0 Loca30 of l release data were emphasized, rather than integral pin data. At 415 W/cm, the local release over the n crospi s section apparentle y Th saturate withi . % h 4 40 2 n t a d central region of the fuel was virtually emplied of fission gas . (Ref7) . 5.2. The RIS0 Transient Fission Gas Release Project (1982 - 85) The most important test paramete e firsth n ti r RIS0 fissios ga n project was the transient power level at given, fairly long hold times. Ther , howeveris e a clea, r interess n datga i tn o a releas f high-burnuo e pn explici a fue s a l t functio f holo n d time. Consequently, the second RIS0 project in this area was

257 launched to study the time dependence of gas release at high burnup. The test fuel comes partly from one of the Danish Halden assemblie d partlsan y fro commerciaa m l BWR e fues Th .i l reconstituted ( "refabricated") in the RIS0 hot cells and mounted with pressure transducers. Important test parametern i s this project are: 0 W-cm)transien50 - ,0 45 to t powe p (u r burnup (13,00 - 050,00 0 MWD/tU) d filt s (Xea an ,ga le H , various pressures). During the transient testing in DR3, the change in internal pin pressur s moniturei e d continuously e pressurTh . e transducen o r the test fuel pin is a diaphragm, that can be pressurized from the outside to balance the internal pin pressure as illustrated in e FigpressurTh . 4 e recorde s connectei r fulla o t d y com- puterized measuring and data acquisition system. This system allows measuring of power and pressure in the experiments with high accuracy. Techniques have been developed for the deriva- tion of gas release in fractions of the produced fission gas with overall accuracie s sinventory ga bette e th r f o tha. % 1 n Releases dow followee 0.1o b nt n %ca d wit resolutioha timn ni e of less tha 1 minuten . e degreTh f e detaiinformatioo eth n i l n obtained from these tests is illustrated by Figs. 5-6.

Fue. I pin

Fig. 4. Pressure Measuring System.

258 TEST MS3-1-6. MRRTS-1 198^. I BRR XENON

30

20 ce ΠCO

U ce •3 (S) (fl LJ 10 Ct CL

0 8 0 6 0 4 0 £ 0 TIM N HOURI E S STORTING FRO : 84.03.02M . 06:00:

Fig . 5 Powe. d Pressuran ra 3-Days r fo e 1 Transient Test

TEST M23-1-6. MRRTS-I 1984. 1 BRR XENON i—————r~

2

Fig. 6. Power and Pressure Around 336 W/cm.

259 RISw Ne 0 A 5.3Fissio. s ProjecGa n t In addition to the detailed knowledge of transient fission gas releas a functio s a e f times also ni t oi , highly desirablo t e be able to me.a.s.ui.e_ the fuel temperature during the test. So t beeno ns possiblha t fari , o perforet m such direct tempera- ture measurement, using fuel that has been previously irra- diate o significant d t burnu a powe n i pr reactor. RISs ha 0 consequently initiate e developmenth d a techniqu f o - t in o t e strument irradiated fuel segments with fresh thermocouples. A RIS0 project is being formulated that will utilize this new technique together with the existing pressure transducer in- strumentation w projecne e s intende.Th i t o includt d e botR hBW and PWR type fuels. As with the previous projects, the test fuel pins will be transient tested in DR3 in the existing facilities, and extensive hot cell examinations will be per- formed before and after the transient testing.

. CONCLUSION6 S ) Realisti(1 R conditionPW c d simulatioan e R ar sBW f o n obtained with the fuel testing facilities in DR3. ) Previousl(2 y irradiated fue le mounte b pin n ca s d with unique instrumentation for on-line measurement of internal pin pressure durin a transieng t test. e informatio(3Th ) n obtained durine b n gca testin3 DR n i g quickly supplemented with extensive post-irradiation examination e near-bth n i sy RIS0 hotcells.

ACKNOWLEDGEMENT The achievements summarized in this paper obviously result from the wor f mano k y people e authorTh . s gratefully acknowledge th e dedicated efforts and collaboration of staff members at RIS0, the OECD Halden Reactor Project and the European Institute for Transuranium Elements at Karlsruhe.

REFERENCES 1. C. Bagger, H. Carlsen and K. Hansen, "Calculation of Heat Rating and Burnup for Test Fuel Pins Irradiated in DR3", RIS0-M-2185, 1980. 2. K. Hansen and J.A. Leth, "Danish High Pressure Irradiation Facilities UseOverpower fo d r Testin f Experimentao g l U02~ Zr Fuel Pins", RIS0-M-1862, 1976.

3. A. Jensen, "LOWI, A New Zircaloy-U02 Fuel Design: Design Considerations, Calculations and Test Results", Nuclear Technology 9 (19783 . ,v . 283 )p .

260 . 4 P.Knudsen Bagge. Fishier. ,C M d an r , "Characterizatiof no PWR Power Ramp Tests", ANS Topical Meeting on Water Reactor Fuel Performance, May 1977, St. Charles (111.). 5. P. Knudsen, C. Bagger and H. Carlsen, "PWR Type Overpower Test t 162a s 0 GJ/kgU (18,800 MWD/MTU)" S TopicaAN , l Meeting on Light Water Reactor Fuel Performance, April 1979, Portland (Ore.). . MisfeldtI . 6 , "The D-COM Blind Proble n Fissioo m s Ga n Release: Experimental Description and Results", OECD-NEA- CSNI/IAEA Specialists' Meeting on Water Reactor Fuel Safet d Fissioan y n Products Releas n Off-Normai e d an l Accident Conditions, RIS0 y 1983Ma , , IAEA Report IWGFPT/16 . 411p , . . KnudsenP . 7 . BaggerC , . CarlsenH , . MisfeldI ,. M d an t Mogensen, "Data Report on the RIS0 Fission Gas Project", RIS0-R-51 published)e b o (t 1 .

261 PROMPT CAPTURE GAMMA-RAY REFERENCE FIELDS AT IMPERIAL COLLEGE

J.A. MASON Reactor Centre, Imperial College, Silwood Park, Ascot, Berkshire, United Kingdom

Abstract Reactor representative high energy gamma-ray reference field n placa s y an important role in the development of metrology techniques for reactor use. This paper describe e implementatioa higth sf ho energe us d y an n prompt capture gamma-ray field in the vertical thermal column of the CONSORT II reactor at Imperial College. The facility, which is based on the concept develope t SCK/CEa d N Mol, Belgium, employs thermal neutrono t s generate an internal prompt capture gamma-ray field. A cylindrical absorber, whic s blaci h o thermat k l neutrons a neutros use i ,s a do t n gamma-ray converter A neutro. n sensitive borated ionization chambes i r n e drivinmonitoru th o d t gan r n thermaru a use s la d neutron flus beeha x n calibrated using an NBS type double fission chamber. Maximum gamma-ray dose rate n excesi s f 100o s 0 R hr~l have been measured using calibrated ionization chambers.

INTRODUCTION

An important e studaspec th f reacto o yf o t r radiation e fieldth s i s characterizatio e gamma-rath f o n y radiation component. This componens i t of increasing importance to reactor designers and operators due to the significant proble f energo m y depositio n reactoi n r structural materials due to the presence of intense, high energy gamma-rays. Unfortunately experimental gamma-ray dosimetry wors generallha k y been restrictee th o t d usf relativelo e w energlo y y gamma-ray sources suc s 60a hC ot whicno o d h adequately represent the high energy gamma-rays found in reactors. It has been necessary to make assumptions about the response of detectors in the higher energy spectra experience n reai d l reactor systems.

The introduction of the thermal neutron prompt capture gamma-ray reference field concept, pioneered by Fabry et al. (1) at SCK/CEN Mol, Belgium, has greatly expanded the range of gamma-ray radiation fields availabl r metrologfo e y experiments e referencTh . e field concept relien o s f thermao e thus el neutron o generatt s e prompt capture gamma-raysA . cylindrical converter or radiator, which is black to thermal neutrons, is place a neutro n i d n fiel a d thermaact an s da s l neutron'to gamma-ray

263 converter A variet. f materialo y e employeb y ma s radiator a d s sucs a h cadmium, cobalt, indium and boron loaded materials. Each radiator produces a distinct gamma-ray spectrum so it is possible to vary the distribution of gamma-ray energiee integrateth d an s d doses see y detectorb n s e placeth n i d field e referencTh . e gamma-ray field concep s beeha t n transferree th o t d Imperial College CONSORT II reactor and adapted for use in the vertical thermal column.

e referencTh e gamma-ray field concep a variet n s ca ha tf uses o yt I . pla n importana y t rol n reactoi e r gamma-ray metrology standardization. Routine use could include instrument calibration and an important applicatio e measurementh e spectras i th n f o t l sensitivit f detectoro y s using different prompt capture gamma-ray radiators. Another aref o a application is in the measurement and unfolding of photofission cross- sections. With the increasing interest in reactor gamma-ray dosimetry, perhap mose th st important applicatio f referenco n e gamma-ray e fieldth s i s measuremen e responsth f o f tdetectoro e n gamma-rai s y fields typicaf o l reactors.

GAMMA RAY REFERENCE FIELD DESIGN

e originaTh l referencMo l e field employs cylindrical prompt capture gamma-ray black absorbers that are suspended in the one meter cavity of the vertical therma 1 reactorBR l e columth . f o nCurrentl ) cadmium(2 y , cobalt and indium radiators have been implemente n additioi d a low o t n, mono- energetic boron radiator mad boroof e n loaded pyrex glass not whic is h blac o thermat k l neutrons n improveA . d boron radiator consistin f hoto g - pressed boron nitride tubing has also been implemented. The gamma-ray background in the system is less than 101 and consists principally of carbon prompt capture gamma-rays and the associated Compton scattering continuum. The one meter cavity largely eliminates the gradient in the driving thermal neutron field. In contrast the reference field has been implemented at Imperial College in a rectangular graphite block which forms the vertical branch to the 90° thermal column of the CONSORT II reactor. The radiator system is inserted into central vertica d penetratel an channe 8 . o No lt s a depth of 1.424m. The system sits in a regio f o exponentian l thermal neutron flux gradient above the horizontal branch e thermath f o l column e locatioTh . f o n the reference field may be seen in Fig.1.

The system as currently implemented at Imperial College consist a cadmiu f o s m radiator 1mm thick and 24cm long supported on a borated pyrex thimble which is 77.5cm long, 2mm thick and has Fig. 1 . n outsida e diamete f 52mme o pyrer Th .x thimble whic he e bottorestth th f t o ma s Locatio f Referenco n e Field channe s connectei l n extensioa o t d n tube

264 made of PTFE and aluminium. A steel shielding plug locates the extension tube in the upper concrete shield. A detector support rod passes through the shielding plug and access is also available for cables. e borateTh d pyrex thimble serves several functions. It may be used as a radiator producin w energlo a gy gamma-ray spectrum dominated by the 480 keV line. As it contain f 6^0se thimblo th onl3$ 13 s yi e t blacno o thermat k s l ha neutron t i d an s the effect of reducing the thermal neutron backgroun abouy b d t 2/3.

The exponential thermal neutron gradient e systeth in m produce a similas r gamma-ray flux gradient. In order to enhance the gamma-ray dose rate and to

Not to icale prevent thermal neutron streaminga , cadmium end cap has been added at the e regioe systeth th basf n o f i nmo e Enlarged Detail highest thermal neutron flux e cadmiuTh . m radiator configuration is illustrated Fig. 2. with an enlarged detector in Fig. 2. Detail of Reference Field Planned enhancements of the system includ e introductioth e a cobal f o nt radiatoe implementatioth d an re e 50c systeth th m n f e i mo cavitn th n i y 270° graphite thermal column. In this position the dose rate will be enhanced and the gamma-ray flux gradient will be eliminated.

NEUTRON CHARACTERIZATIO D FLUAN NX MONITORING

Both the thermal and epithermal neutron fluxes have been measured in the vertical thermal column with and without the radiators present in order to characteriz e system th ee measuremen Th . t technique sS typusinNB en a g double fission chamber and CR-39 solid state nuclear track detectors (SSNTD) were described in detail in an earlier paper (3) and will not be emphasize n thii d s paper.

Initiall e drivinth y g thermal neutron flu s measuren channei wa x 8 o N ld using the NBS type double fission chamber. It had previously been established thae maximuth t m epitherma o thermat l l fluxe ratith n i o channe s lese i measurel Th s tha. 1$ dn exponential driving thermal neutron flux in channel No. 9 is plotted as Fig. 3. The flux in the reference field channel is enhanced by a factor of 1.16.

265 e backgrounTh d thermal, epithermad an l fast neutron fluxes insid e pyreth e x thimble and black absorber cadmium radiator were measured using CR-39 SSNTD S typNB e e andoublth d e fission chamber. e thermaTh l neutron flue s founb wa xo t d e ordeth f 10"o rf o n cm~e loweth 2 s~n ri 1 e cadmiuth hal f o fm radiator risin5 o t g x 10e 6nth f cm~o 2s~p to 1 e neath r cadmium cylinder due to thermal neutron streaming from above. The fast neutron component above 2 MeV was measured as approximately 2 x 105n cm~Js~1 at the e cadmiuth bas f o em radiator, adjaceno t the end cap.

In order to provide long term, reproducible run to run neutron flux J__I monitoring a ,boro n lined current type thermal neutron sensitive ionization chambe s installe wa re horizonta th n i d l Fig. 3 . ° therma90 e brancth l f columo h n which Axial Thermal Neutron Flux drives the vertical branch in which the reference field is located. The location of the flux monitor may be seen in Fig. 1. and the position was chosen so thae monitoreth t d thermal neutro t perturben no flu s i x d eithe y reactob r r fine control rod movements or the presence of the gamma-ray reference field. The run to run flux monitor has been calibrated against reactor power, driving thermal neutron flux in the reference position and gamma-ray exposure rate in a fixed position in the reference field.

GAMMA RAY MEASUREMENTS Con ' i qurat ion Lxposure Rate (R h ) Gamma-ray measurements have

Pyrex tube, Cadmiurr sleeve with end cap 716 bee e referencn th mad n i e e field with several

Pyrex tu be only 1 14 techniques although only exposure rate measurements d Cuda" T rro-e d uri < e r jb r, t x Pyre 83 made with neutron insensitive graphite

P> t PX t Joe inii C~uln - <-., 1 ef\ P ^ "Sta 1 ] ed , ionization chambers are 7!5 Cai-i^ium -Ti [ .i d H."U'„H< Ü reported here. Two chambers designed by Berkeley Nuclear Laboratories (BNL) (4) have been e Th firsusedt. Tabl. 1 e chamber is designed to Reference Field Exposure Rates simulate a MKII ICRC graphite microcalorimeter

266 and measurements using this chambea t a r reactor powe f 100ko re tabulatear W n i d e activTh Tabl e. e 1 th evolum f o e chamber extends over 5cm so that it is located in a region of gamma-ray exposure gradient. It has been used to measure exposure rates for differenct radiator configurations includin e measurementh g t Cadmium court* e backgrounth o carbot f o e du nd prompt captur d coran ee leakage gamma-rayse Th . high background effectively precludee th s

.,800 use of the pyrex radiator and provides motivation for the relocation of the w backgrounlo syste a o t m d regiof o n uniform thermal flux.

Measurements have also been performed \ with a miniature BNL graphite chamber and the resulting exposure rate profile is plotte s Figa d. 4 .

6 - < 2 Po« dor from bottom (cm) CONCLUSIONS

Fig. 4 . The gamma-ray reference field is a useful Exposure Rate Profile e developmenth toor fo l d calibratiotan n of metrology techniques. Reference e employefieldb y ma so simulatt d e higth eh energy gamma-rays a foun n i d reactor environmen d thean ty hav a valuable e rol n reactoi e r gamma-ray benchmark experiments. Thee relativelar y y inexpensiv o instalt e n i l existing reactor thermal columns and they can serve as powerful research tools.

e authoTh r wishe o than t s. T.A Mr k . Lewi o performeswh e ionizatioth d n chamber measurements and he wishes to acknowledge the assistance of . A.NMr . Asfa o performerwh e neutroth d n measurements.

REFERENCES

. FabryA 1. . MinsartG , . DeLeeuwS . CopF d , an s , "Thl CavitMo e y Fission Spectrum Standard Neutron Field and its Applications," Proceedings of the Fourth ASTM-EURATOM Symposium on Reactor Dosimetry, Gaithersburg, Maryland, USA, 1982.

, FabryA . 2 , "Generatin d Usinan g g Reactor Reference Radiation Fields," f ResearcIAEo e A Us Semina e h th Reactor n ro n Fundamentai s d Appliean l d Sciences, Tajoura/Tripoli, Libya, 1984.

3. J.A. Mason, A.N. Asfar, T.C. Jones, A.M. Fabr d M.Ran y . Menu, "Characterizatio e Imperiath f o n l College Reference Gamma-Ray Field," Proceeding e Fiftth hf o sASTM-EURATO M Symposiu n Reactoo m r Dosimetry, Hamburg, Federal Republic of Germany, 1984.

. 4 S.J. Kitchin d T.Aan g . Lewis n Ionizatio"A , n Chambe r Measurinfo r g Gamma Exposure Raten i Mixes d Radiation Fields," report TPRD/B/0348/N83, Central Electricity Generating Board, Berkeley Nuclear Laboratories, 1983-

267 NEUTRON ACTIVATION ANALYSIS AT THE DANISH REACTOR DR3

L.H. CHRISTENSEN . DAMSGAARE , D Isotope Division, Ris0 National Laboratory, Roskilde, Denmark

Abstract Irradiation facilities, counting equipment, and methods of cal- culation for neutron activation analysis at the Danish reactor e describedar 3 R D . Both neutron activation analysis with radio- chemical separation (RNAA) and instrumental activation analysis (INAA a routin e carrien o ar ) t e ou dbasis .

INTRODUCTION

n 193I 0 neutron radiatio s observee firswa nth r t fo timdd an e in 1932 Chadwick identified the particles and named them. In 1934 Jolio d Curian t e discovered that natural radioactive material could induce activit n othei y r materials o yearTw . s later Hevese Niel th d Lev t an sya iBoh r Institutf eo made us e thi se determinatio effecth a sampl r n i fo tf rare o ey D f -o n earths and, thereby, gave birt o neutrot h n activation analysis. Irradiation facilitie w availablno e ar st mana e y researc- re h actors throughout the world, and neutron activation analysis is a well established analytical technique, which contributes to technical progres n mani s y e occasioareas e th 50t th n h O .f o n anniversar e firsth f to ypublicatio h y Hevesb n7t d Leve an yth i International Conference on Modern Trends in Activation Analysis wil e hel b ln Copenhage i d n 1986i n .

The Isotope Division has been active in the field since 1966 [1 ]. The prime research interest has been application of neutron activation analysis to clinical trace element studies [2].

However, since 197 e Danisth 4 h National Science Research Council has supported the instrumental neutron activation facilities at Ris0 making these availabl e scientifith o t e c communit n Denmarki y ,

269 Several thousand f sampleo s f rockso s , minerals, soil, sediment, plants, mussels, fish, etc. have been submitted to activation analysis a numbe r f Fo year.o r e laboratorth s s beeha yn involved in certification campaign sC Burea organizeEE e f o uth y b d Reference (BCR), and this work continues to be a major effort. Lately, industria f activatioo e us l n analysi s growha s n consider- ably.

The aim of the present paper is to discuss activation analysis e Danisth s carriet i a h t i t reacto . ou Exampleds 3 a R D r s illus- tratin e applicationg th som f r o eresearc ou d an s h efforts within these area e presentedar s .

STANDARDIZATION PROCEDURES

r RNAFo A quantificatio e relativ s baseth i n n o d er methofo d an d e singlth INA n o eA comparator method [sj e relativTh . e methos i d characterized by simultaneous irradiation of samples and stan- dards of the elements to be determined. The single comparator metho e experimenta s baseth i d n o d l determinatio e ratioth f o sn of specific count-rates of an element and a comparator. As com- parator we use laboratory-prepared solutions of Mn for short ir- radiations and for long irradiations analytical-grade either alone or in a mixture with pure

Ratio f specifio s c count-rates, often referre s ka o-factors o t d , may also be calculated from known nuclear data. Moens et al.

] hav[4 e tabulate d comparean d d experimentally determine- o k d factors with those calculated. Some discrepancies were observed ann generai d l experimentally determine e dpreb factoro -t e ar s

ferred. The ko-factors tabulated by Moens et al. are independent f irradiatioo d measurinan n g condition s suca d h an sapplicabl e o gamma-rat y spectroscop n generali y .

Preparation of standards is a tedious procedure and it is often difficult to verify the content of a particular element in a primary standard by an independent analytical technique. This is especially the case for some of the rare-earth elements. There-

270 fore our quantitative approach for routine applications of INAA is based on a combination of experimentally determined, calcu- lated, and/or tabulated ko-factors.

In certification campaigns it is a requirement that analytical result e base ar sn laboratory-prepare o d d primary standards made from analytical-grade chemical compound f knowo s n stoichiometry. Our primary standards are frequently verified by means of an independent technique.

EXPERIMENTAL

Irradiation facilities

Special irradiation facilities in the Danish "10 MW heavy-water- moderated reactor DR 3 include an air-cooled pneumatic tube and a C02~cooled rotating rig. These facilities are installed in vertical tubes extending into the heavy water. The flux specifi- cation e show ar e spneumatin Tabl Th i n . 1 e c system allows trans- fer of samples in 20 s for measurement of short-lived indicator isotopes e rotatinTh . g assembly contains three tubes, eacf o h whico fivt n hol p ca ehu d aluminium can f eaco s p hplaceto n o d other o ensurT . e flux homogeneit n cani y s e samplaceth en i d horizontal position, the rig shown in Fig. 1 rotates around its vertical axis with a revolution time of 10 minutes. The neutron spectrum of the DR 3 reactor is characterized by a low epi- thermal and a low fast flux. The former condition allows the use of the single comparator method for multielement deter- mination [5J, whil e latteth e r condition ascertain w nucleafe s r interferences.

Table 1. Neutron "lux densities in the irradiation facilities.

Facility Pneumatic tube Rotating ri g R4V4 7V2

Thermal neutrons 17 1 7 per m2 x s 2.5 * 10 4.5 x 10 Epithermal neutrons per m«? x s 0.4 x 10 15 2.0 - 101 5 Fast neutrons

per m2 x s 3 x 10 T 4 10' 5

271 fuel i t n « m tt I e

Irradiation cans

Fig. 1 . Irradiation position 7V2 in DR 3 wl t r, the rotating g facilityri .

Counting assembly e countinTh g assembl s virtualli y e samr gamma-rath yfo e y spec- trometers base n verticallo d s wela ys horizontall a l y configured detectors, whether these are of the scintillation type or the solid state type. The lead coffins designed and constructed at Riso contain a Perspex box providing a total of seven discrete counting position r accuratfo s e locatio f samplno e holders; each step represents a change in counting geometry of close to a facto f twoo r . Thus samples differin y morb g e thao ordertw n f so magnitud n activiti ee counte b y ma y d wite samth h e detector

112 Fig. 2. Horizontal lead coffLn for counting witn a Ge'Li detector.

under accurately reproducible counting conditions A .horizonta l arrangemen r countinfo t g wit a Ge(Lih ) detecto s showi r n Figi n . 2. The Perspex box shown as an insert illustrates that modifi- cations require y differenb d t detector t affecno e sourc o th d ts e compartment.

Reproducible counting geometr s determinei y e th r onl no y db y precisio f countino n g position e sizd shap th t alsan e f bu ,y o e b o the sample. The use of standard half-dram polyethylene vials for all countings ensures precise positioning. Difference- ge n i s ometry between samples and comparator are limited to variations in volume.

Counting equipment

A tota f fivo l e Nal(Tl r Ge(Lio d fou an )e G r ) detectore ar s availabl r routinfo e e activation analysis. Specificationr fo s the solid state detectors are given in Table 2. The detectors e connecte ar o Intertechniqutw o t d e Histoma N tanalyzers - Nu a ,

273 clear Data ND62 analyzer a Nuclea d an , r Data ND680 multichannel analyzer-microcomputer system accommodatin o fout p ru g spec- trometers e single-job/single-useTh . r e naturoperatinth f o e g e systemicrocomputerth f mo , i.e. C RT11 ,s DE requireha , d devel- opmen a softwar f o t e package providin a gsimulate d time-shared environment. Hereby it is possible to accumulate data and at the same time use the computer for preliminary data reduction of previously acquired spectra, programming purposes, and as an intelligent terminal directly coupled to the central com- puter facility, i.e., a Burroughs B7800.

Tabl . Specification2 e e solith r d fo stats e detectors usey b d the Isotope Division.

Internal Manufacturer Type Volume FWHM Efficiency no. cm3 keV %

52 Canberra Ge(Li ) 9 2 1.96 4.9 coal xia 62 Princeton Ge(Li) 55 1.71 10.8 Gamma-Tech coaxial 72 Ortec Gainma-X 60 1.62 10.5 84 Princeton Ge(Li )

Gamma-Tech coaxial 0 5 1.81 7.7 * FWHM: Full widt t a hhal f iraximum measure < 133 * dV ( Co)60 ke 2 . Efficiency measured relative to a 3" * 3" ^?I'T1) detector with a source to detector distance of 25 en. n ordeI o takt r e full advantag r high-resolutioou f o e n solid state detector o covet n d energa ran s V wite yMe th hrang3 f o e same energy calibration 80-200 MHz ADC's are used with a con- version gain of 8K. Dead time correction is based on the pulser technique using high precision Orte 8 puls44 c e generators.

Irradiatio d countinan n g strategy

The irradiation and counting time as well as the number of ir- radiation d measurementan s r samplpe s e preferablar e y tailored to the element under investigation. However, in order to take

274 advantag e multielementh f o e t capabilit f instrumentao y l neutron activation analysis several compromises have to be made. The half-lives of indicator isotopes for elements amenable to ther- mal neutron activation and gamma-ray counting span many orders of magnitude and so do the cross sections for nuclear interactions. It is therefore impossible to optimize the experimental con- ditions for all elements at the same time. Typical conditions for determining short- and long-lived nuclides by instrumental neutron activation analysi e show ar sTabln i n . 3 e o farS projecte ,th mos f o t s sponsore Danise th y hb d National Science Research Council have made use only of the long ir- radiation t botbu , h shor d lonan t g irradiation e providedar s .

Table 3. Typical experimental conditions for determining short- live d long-livean d d nuclides.

* * * Duration Facility fci * t Sample size type a c mg

short R4V4 15s-10m 1-30m 1-30n 10-500 2 7V long 1-12h 3-7d 1-2h 10-500 25-30d 3-4h

* t£, t,-}, tc irradiation, decay, and counting time, respectively.

DATA TREATMENT

Determination of peak areas

Acquired gamma-spectra may either be processed at the Isotope Divisio e transmitteb r o n o Riso'st d central computer where data processing takes place. Own, as well as acquired computer programs are used for the calculation of peak locations and peak areas A .progra m SPE s characterizei C y locatinb d g peak boundaries from the sign change of the first derivative of the smoothed spectrum [s]. Boundaries can also be selected manually. The program PEAK uses optimum peak boundary selection described by Heydor d Ladan na [?]. Spectr n als ca e aprocesseb o e th y b d Nuclear Data Peak Search Progra ] whic [s ms basea non i h n o d- linear least squares Gaussian fitting routine. Finalle th y

275 program SAMPO80 [9] is employed where overlapping peaks are not resolve D prograr N whero d e s failedth e ha m .

Quantification

For RNAA the peak areas are converted to element concentrations using individual calculation r eacfo s h element r multielemenFo . t determination by INAA a program TELCO calculates concentrations base a librar0 gamma-line n 35 o d e identificatiof o yth r fo s f o n up to 57 elements. The library is currently being updated to in- clude more elements and more recent nuclear data.

The TELCO program includes in its calculations uncertainties from counting statistic e elementh r n questioi fo ts s wela ns a l for the comparator, but does not yet consider possible correc- tions for interferences from other elements. Interferences are evaluated separately r shorFo . t irradiation e pneumatith n i s c a priortub n a e i estimated standard deviatio f 3.5o n % muse b t e countinaddeth o t d g statistic o account s r flufo tx variations.

SOURCES OF ERROR

Peak deconvolution algorithm

Routine instrumental neutron activation analysis makes use of the Nuclear Data peak search algorith r spectrafo m l deconvol- e betteutionth f o r .commerciae Althougon s i t i hl computer program r spectrufo s m analysi t doet i always no s s yield accurate result n statisticai s l control [lu] e prograTh . s basea i m n o d non-linear least squares Gaussian fitting algorithm with no constraints on the fitting parameters. The algorithm often yields significantly different full widths at half maximum value r adjacenfo s t peaks, which evidently causes wrong peak areas t presenA . a sourc e prograe th b tf error o ey ma t m bu , n progresi wor s i k o improvt s e algorithmth e .

276 Spectral interferences

It is not always possible to base quantification of a particular elemen n interference-frea n o t e gamma-line. Some indicator isotopes only emie lineon t , others several lines n geologicaI . l samples where the determination of rare-earth elements is of prime importance interference problems often arise n TablI . 4 e we have listed some of the dominant cases.

Tabl . Example4 e f interferenceso s .

Isotope Line Interfering Alternative lines keV V ke isotopes

1 223 ,153 53Sm 103.2Tn Gd

(233Pa)

160Tb 298.5 233Th 1178.0, 879.3

(233Pa)

169Yb 197.1608Tb 177.0

175Yb 396.2331Th

Blanks

e presencTh f uraniuo e a sampl n i m e increase e truth se values of La, Ce, Nd, and Sm if appropriate corrections are not made r interferencefo e indicatoTh . r isotope r thesfo s e elemente ar s also produced from the fission of 235(j [2, p 43 J. In a recent . s [11showal wa t t Jni e thaa pape li a tfiv y b re hou- ir r f uraniuo radiatio g p 1 m f causeo n s blank value f d 0.2o san g 8w 0.23 ug of Ce and Nd, respectively. The equivalent blank value e dependens founb wa o t a dL r t fo upo- e delair th n f yo frod en m radiation to sample counting.

When dealing with trace element analysis, another sourc f erroo e r e presencith s f elemento e e half-drath n i s m polyvials uses a d irradiation containers. Samples mus e transferreb t o unirt d -

277 radiated polyvials before counting if the blank value is sig- nificant t. 12 ] . Recent data for blank values are presented in Table 5.

Tabl . Element5 e n half-drai s m polyvials.

Element ng Element ng Element ng

Ag 1 .5 Cr 15 La 0.3 Al 400 Cu 30 Sc 0.06 Au 0.3 Eu 0. 02 Sm 0.03 Br 20 Fe 1 000 Sb 0.7 Ce 2 Hg 0.2 V 5 Cl 3000 Mn 10 W 1 Co 0.7 Na 300 Zn 120

Quality assurance tests

r qualitOu y assurance program comprises several tests, somf o e whic e describear h d below e progra. o participatth Part f s o ti m e as often as possible in international intercomparisons and to frequently analyze available reference materials.

Recently we have verified calibration of our different spec- trometers by analyzing six geological standards, i.e., AGV-1, BCR-1, GSP-1, G-2, PCC-1 d W-1an , n .FigI e havw .3 e compared our results for some elements with the consensus values recently published by Gladney et al. [13]. As seen from Fig. 3 systematic errors are not observed. e besth t f qualito e On y assurance test s Analysii s f Precisioo s n [l4]. Whenever possible analyses are carried out in replicates and Analysi f Precisioo s s use i no determin t d e whethel al r sources of error have been considered. An example of this is the IUPAC interlaboratory tria n traco l e element n urini s e candidate reference material. As, Mn, and Se were determined by RNAA and Tabl 6 showe s tha e resultn statisticai th t e ar s l control, i.e., the probability P that x2 exceeds the test parameter T is greater than 0.05 correspondin % significanc5 a o t g e level.

278 200 INAA La 160

120

80

40' GLADNEY83 6 8 10 40 80 120 160200 25 INAA • Sm 20

15

GLADNEY83 100 200300400505 2 0 2 5 1 0 0 1 5

INAA : Yb

GLADNEY83 .6 2.0

. Compariso3 Fig. f INAo n A result d consensuan s s values x geologicasi r fo l standards, i.e., AGV-1, "CR-1, GSP-1, G-2, 1 (FePCC-1W- d : an , result l otheral s ; give« s n i n

Table 6. Analysis of urine 108 candidate reference material

Eleiren t T Nunrbed.f f o r . Mean value sairples mg/m-*

As 6 7.175 247 ± 5 Mn 6 5.27 5 21.0 ± 0. 3 Se 6 6.875 . 40.1 ± 5 9

Analysi f Precisioo s n 19.3 5 1 1 = 0.2P(x ) T 0 = 2

279 REFERENCES

[l] HEYDORN, K., LEVI, H., RIS0-R-401, 1979. ] HEYDORN[2 , NeutroK. , n Activation Analysi r Clinicafo s l Trace Element Research, Vol. 1-2 (CRC Press, Boca Raton, 1984 ). [3] GIRARDI, P., GUZZI, G., PAULY, J., Anal. Chem. r? (1965) 1085. [4] MOENS, L., De CORTE, F., De WISPELAERE, A., HOSTE, J., SIMONITZ, A., ELEK, A., SZABO, E., J. Radioanal. Nucl. Chem (1984^ 82 . ) 385. ] DAMSGAARD[5 , HEYDORNE. , , RIS0-M-2141K. , , 1978. [6J YULE, H.P., Anal. Chem. 3_8 (1966) 103. HEYDORN[7] LADA K., , Anal,W., . Chem. _4_4_ (1972) 2313. [Q] Nuclear Data Inc., ND6600 Peak Search Program Algorithm, ND-004A, Schaumburg, 1980. [9] KOSKELO, M.J., AARNIO, P.A., ROUTTI, J.T., Nucl. Instr. and Meth. 190 (1981 ) 89. [10] HEYDORN, K., Proc. Conf. Computers Act. Anal. Y-Ray Spec- troscopy (1979) 85. [11] ILA , JAGAMP. , , MUCKEP. , , G.K. . RadioanalJ , . Chem. _7J) (1983) 215. [12] HEYDORN , DAMSGAARDK. , , TalantE. , 9 (19822^ a ) 1019. [13] GLADNEY, E.S., BURNS , ROELANDTSE. , Geostandard, I. , s Newslette 198( - _ 3 T 3r) [14J HEYDORN, K., N0RGAARD, K., Talanta 20 (1973) 835.

280 NEW NEUTRON SCATTERING INSTRUMENTS A RIS0 NATIONAL LABORATORY: A MULTIPURPOSE SPECTROMETER SANE TH S D FACILITAN Y

B. LEBECH, T. FRELTOFT, D. JUUL JENSEN, C. BROHOLM, K. CLAUSEN, L G. JENSEN, J.K. KJEMS, K. MORTENSEN Physics Department, Ris0 National Laboratory, Roskilde, Denmark

Abstract

Two neutron scattering instruments recently installed at the DR3 reactor at Ris0 National Laboratory is described and example f experimentao s l result e givenar s .

One instrument is a multipurpose instrument TAS3 which can be operated in three different modes: 1) TAS-MODE: In this mode the detector system consists of a complete analyser-detector e systeminstrumenth d an , s i t a conventional neutron triple-axis-spectrometer used for inelastic neutron scattering. ) DAS-MODE2 n thiI : s mode detectoth e r system consista f o s detector system, which can be rotated around the vertical sample axis and in addition by means of an automated mech- anica e tiltelb tiln ca dt fro ° abov° belo5 25 me o th et w horizontal plane. The spectrometer is used for elastic neutron scattering. 3) DPS-MODE: In this mode the detector system is a linear position sensitive detector which is mounted vertically in the mechanical tilt device used in the DAS-mode. The DPS- mode supplements the DAS-mode and has proven to be useful in single crystal structural studies when searchinr fo g satellite Bragg d directionpeakod n i s f reciprocao s l space. ) TEX-MODE4 : This mod s user measurini e fo d g textur f polyo e - crystalline materials, both statistical and dynamical. An Eulereian craddle is mounted on the sample table, and the detector system consist a linea f o s r position sensitive detector mounted as in the DPS-mode. The other facility to be described is the six meter Small Angle Neutron Scattering facility s situateSANSi t a colI . t da d source beam outside the DR3 reactor confinement at the end of a 20 m long neutron guide. A mechanical velocity selector with variable tilt provides the monochromatization with AX/X. in the range 0.05 to 0.20. As a novel feature the sample is placed in high vacuum, (< 10~6 mbar), without windows between the entrance

slit and the 40 cm 40 cm area-sensitive detector. The sample e rotateb n d translateca an d d automaticall e vacuumx th n i y , which f cryostatso e allowus e th s, cryomagnet d furnacean s s without introductio f extro n a windows e instrumenTh . t uses neutron A witwavelength 4 h2 o momentue t rang th A n 4 ei s m transfers in the range 0.2 A~1 to 0.003 A-1.

281 1. THE MULTIPURPOSE NEUTRON SPECTROMETER TAS3

e multipurposTh e neutron spectrometee th f s installeo i r e on t a d tangential thermal neutro ne experimentabeamth n i s e l th hal f o l e operateb 3 reactor DR y ma t df threI .o usin e eon gdifferen - de t tector systems e spectrometeTh . s fulli r y automise d controllean d d by a PDP-11/23 computer with both hard and floppy disc drives. A CANON computer wit k plottea colouh- in di t s ri je r screea d an n rectly couplee PDP-1 th r on-lin o fo t 1d e graphical presentation e measureth f o r simpldfo datd ean a data analysis e mechanicaTh . l parts of the spectrometer are designed so that change from one detector system to another can be made within a couple of hours. The different detector systems with appropriate computer programs allow the spectrometer to be operated in the following four modes:

1) TAS-MODE n thiI : s mode detectoth e r system consistf o s a complete analyser-detector e systeminstrumenth d an , t is a conventional neutron triple-axis-spectrometer used for inelastic scattering experiments. ) DAS-MODE2 n thiI : s mode detectoth e r system consista f o s detector, which can be rotated around the vertical sample n additioi axid an sy n meanautomate b a n f o s d mechanical tilt can be tilted from 5° to 25° above the horizontal plane. In the DAS-mode the spectrometer is used for elas- tic neutron scattering experiments. 3) DPS-MODE: In this mode the detector system consists of a linear position sensitive detector whic s mountei h d ver- tically in the mechanical tilt device used in the DAS- mode. The DPS-mode supplements the DAS-mode and has proven e tusefub o n singli l e crystal structural studies when searching for satellite Bragg peaks in odd directions of reciprocal space. ) TEX-MODE4 : This mod s user measurini e fo d g in-situ kinetic textur f polycrystallino e e materials, both statisticad an l dynamical. An Eulereian craddle is mounted on the sample table, and the detector system consists of a linear pos- ition sensitive detecto e DPS-moder th mounte n i e s Th a .d technique samples crystallographic changes withi a buln k material. This type of in-situ information is not directly

282 accessible by other standard measuring techniques, and combined with, for example microscopical investigations of the change in microstructure, fast in-situ neutron dif- fraction texture measurements can serve as an important tool for a further understanding of basic physical metal- lurgical processes.

In the TAS-, DAS-, and DPS-modes, cryostats/furnaces to cover sample temperatures ranging from 0.0 d supercon5o 200t an K 0 - ducting magnets with fields up to 10 T are available. In the TEX-mode e e heatesamplr b blowe th ,ai n ca dt er ho eithe a y b r (up to 700 K) or by use of a small special furnace (up to 1500 K) .

Below we give examples of the use of the instrument operating e DASith nr DPS-mod-o e (1.1. a studa magneti r f o yfo ) c struc- e TEX-modth n i turd e e an recrystale (1.2. a studth r f o yfo ) - lizatio n aluminiumi n .

1.1. Example of operation in the DAS- or DPS-mode

In the DAS- or DPS-mode the spectrometer is operated without n analysea s assumei r t systei d an mthal scatterinal t g reaching the detector is elastic. Hence the information gained in these modes is mainly structural.

Typical for structural studies of single crystals are that to perform a proper analysis there is a need for data from more than one plane of the reciprocal space without having to re- orientat e crystath e l manually. Such informatio s mosi n t often and quite succesfully achieved by use of neutron four-circle instruments. However r instancfo , r studiefo e f magnetio s c structures and phase transitions, use of heavy cryostats and bulky super-conducting magnet r pressuro s e cell e quitar s e often necessar n orde i yw temperatures o obtailo t r e th n , high magnetic field r pressureo s t whic a se magneti th h c ordering takes place. Four-circle instrumentt presena t - no de t e ar s signe o carrt d y heavy e presenloadsth d an ,t instrumene th n i t

283 DAS- or DPS-mode has proven a useful compromise between a four circle diffractometer and a conventional two-axis-diffractometer,

Figur 1 showe a smechanica l drawine detectoth f o g r systeme Th . detector is placed in a radiation shield (A) and mounted on the detector table (B), which may be tilted from 5° below to 25° abov e horizontath e l plane. Mechanically- de e th e til f th ,o t tector table is achieved via a chain drive (E) driven by gear wheels (F), which via a gear box (G) (1:500) is connected to a step motor (H) that can be automatically controlled from the PDP-11 spectrometer computer. The distance between the sample

////////////////////// H ////// / / /// /

Fj.^._K Detector system for the multipurpose instrument in the DAS-, DPS d TEX-modes-an - radiatio .A n shield with detector, - detectoB r table - horizonta C , l movemen f detectoo t r table, D - air cushions, E - chain drive, F - gear wheels, G - gear box, H - step motor.

284 and the detector can be varied manually (C) from -120 mm to +12, thumm 0 s allowin e use th ga convenienr t choic f resolo e - utio d accesablan n e e reciprocavolumth f o e l space without changing for instance the incident neutron wavelength.

The detector system moves on three air cushions (D) and may be rotated around a vertical axis through the centre of the sample table e settine spectrometeTh .th f o g s controllei r e th y b d PDP-11 computer and can be specified by the four spectrometer

angles e coordinatee,9s,u>, - sre (h,k,Ae th f o ) M ciprocal lattice samplth f eo e (Miller indices). Here^ ,20 e scatterin g refeanth 9 2 do t r g e monochromatoangleth f o s r and sample, respectively and w and define crystal rotation aroun e verticath d d horizontaan l l (tilt) axes, respectively.

An exampl n orderea f o e d magnetic material whic s beee ha hth n subjec f detaileo t d elastic neutron scattering experimentt a s Ris0 and elsewhere (Rossat-Mignod et al. 1977, Fischer et al. 1978, . 1978Meieal t e r, . Lebec198al e d 1986t 0e th han s i ) rare earth monopnictide CeSb which crystallize e rockth n -i s salt structure. Belo = 16. N T w K ther2 e exist x differensi s t ant iferromagnetic structures having periodicities commensurate wite underlyinth h g crystal lattice o exampleTw . f theso s e structures are shown in Fig. 2. The superimposed periodic mag-

(b) ilOOH

o

.- noö^ i 11001

[010] (0101

Example. Fi2 g. f antiferromagnetio s c structures observen i d CeSb in zero applied field (after Fischer et al. 1978)). In (a)

. K 1 . 16 = N T r 15.< fo T ) 9 < (b n < 8.9i T d Kr an fo

285 netic scattering e simplesgiveth n i s t case ris o magnetit e c satellite reflections displaced +Q and -Q from the Bragg peaks associated with the nuclear periodicity. For more complex mag- netic structures than the ones shown in Fig. 2, it is customary to describe the structure by its Fourier expansion. Experimen- tally, additional higher order magnetic satellite e observear s d at ± 2Q, ± 3Q ... etc. away from the Bragg peaks of the crystal lattice e intensitieTh . f theso s e satellite e (aparar s t froa m factor dependen e momenth n o t orientation relativ e scatth o -t e tering vector and the magnetic formfactor) proportional to the amplitude of the Q-component in the Fourier expansion of the magnetic structur d yieldan e s information abou e ordereth t d magnetic moment.

In CeSb e tetragonath , l symmetr e ordereth f o yd fase, creates three symmetry related magnetic domains with three orthogonal modulation directions n ordeI . o determint r e domaith e n popu- lation and the total ordered moment of the magnetic structure of a given phase, it is therefore necessary to measure scat- tering out of the horisontal plane as well as in the horizontal plane n thiI . s situation e DAS-modth , f TASo e 3 becomes useful. Figur n 3 examplshowea s e a magnetis th e c Bragg peak t 13.a s K 1 of two domains. The (2QO) satellite (y-domain) of the Q = 4/7 structur f CeSo es showi b s fillea n d circles e satellitTh . f o e th x domaie n (Q20) shows similar behaviour e z-domaiTh . n (20Q) (unfilled triangles) was measured by tilting the detector as described above. It is evident that the resolution in this type of measurement is poor due to the relatively relaxed vertical collimation. For a determination of the domain population it is however sufficient. Accurate determination of the value of 0 will normally be carried with zero detector tilt. I.e. in the example of CeSb Q will be determined from the positions of the (2QÜ) and (Q20) satellites with scattering triangle in the horisontal plane,

If very little is known about the magnetic structure, the first step in the determination of the structure may be tedious because magnetic satellites in general can occur anywhere in the three dimensional reciprocal space. For obtaining a first overview of the situation it becomes important to collect a large amount

286 _ ^_ 1500

lOOÜ

SOC ..

0 . 50 0.60 0 . 70 Q/R.L.U. Fig . 3. Examples of magnetic satellites observed in CeSb using the multipurpose instrumen e DAS-modeth n i t • show. e satelth s - lite at (2QO) observed for a magnetic domain with the y-direc- tion as preferred axis (detector tilt = 0°). A shows the satel- lite (20Q) corresponding to a z-domain of the magnetic structure (detector tilt > 0°). The different background levels for (2QO) and (20Q) are caused by different detector aperture and hence different effective collimation.

of data which neet have qualitno dth e y necessar a fina r fo yl structural determination r thiFo .s purposs proveha t i ne useful a positio e us o t n sensitive detector (DPS-mode) insteaa f o d conventional detector. This allows collectio f intensito n y data covering three dimensional curves in reciprocal space, whereas a conventional detector measures the intensity point by point during normal operation. Withi a relativeln y short time, data cap be collected in the DPS-mode, which may be used to produce two dimensional map f equao s l intensity contour f elastio s c scattering. At the moment it is not quite clear how best to presen e datth t a graphically e DPS-modth t s bu bee, ha e n shown to work on the known magnetic structure of CeSb (Broholm 1985).

287 1.2. Exampl f operatioo e e TEX-modth n i n e

e TEX-modIth n e spectrometeth e e user b fas fo dn t ca rmeasure - ments of texture in polycrystalline materials. Information about the distribution function of crystal orientations, or the texture e materialoth fe use b o predic t n d ca , t macroscopic properties of the material and therefore also the possible applications of the material (Bunge 1984). Furthermore y fasb , t on-line measure- e texturamentth f o s l changes during metallurgical processes like plastic deformation, recrystallization and grain growth, kinetic information is obtained about the crystallographic pro- cesses that take place in the bulk material.

When user texturfo d e studies e spectrometeth , s equippei r d with an Euler goniometer (Eulerian cradle) use o changt d e samplth e e orientatio a linea d an nr position-sensitive detector placed with its axis vertical along a Debye-Scherrer ring (Juul Jensen and Kjems 1983) t presenA . a complett e texture analysis require6 1 s to 30 minutes measuring time depending on the sample material. Thus it is possible to make accurate kinetic investigations of processes which involve texture transformations over at least a coupl f hourso e e kineticTh . f vero s y fast processes, where th e achieved time resolutio s insufficienti n e followeb n ca ,y b d measurements that focus on selected texture components only. (Here the sample orientation is changed between a few presel- ected positions.) In the limiting case, the sample is kept fixed during the measurements, whereby a time resolution in the orde f secondo r s obtainedi s . e potentia Th e techniquth f o ls bee ha e n demonstrate y in-sitb d u kinetic investigations of recrystallization and grain growth in various polycrystalline materials (Juul . Jense1985al ,t e n Grant et al. 1984). As an example, Fig. & shows the development of different texture components during recrystallization of heavily deformed aluminium. From such results precise kinetic information is obtained, which can be used to determine import- ant overall characteristics, e.g. the time for 50% recrystal- lization. Combined with microscopical observations the kinetic texture results give an improved understanding of both the nu-

288 O |110J <001> * (110) <112> h * |123) (630 « {112J <111) D |100| <001) 30 [

Fig. 4. The development of specific texture components during isothermal annealing at 240 °C of commercially pure aluminium cold reductiorolle95% to d thicknessin n datbeeThe . has a n obtained using the multipurpose instrument in the TEX-mode.

cleatio d growtan n h processes taking place during recrystalliz- ation (Juul . Jense1985)al t e n. Furthermore e resultth , n ca s be use o evaluatt d e kinetic models n illustratioA . f thio ns i s shown in Fig. 4, where the measured data are fitted to an Avrami equation (Avrami 1940), which commonl s use i yo describ t d e th e recrystallization kinetics. It is seen that the equation gives a e reasonablmeasureth o t t d fi epoint d thereban s n accurata y e determinatio e fitteth f do n parameters. However, whee valuth n e f theso e parameter s comparei s d wite resultth h s from micro- scopical observations it is found, that a simple growth model as assumed in the Avrami interpretation, fails to describe the present recrystallization process. This resuln agreemeni s i t t with earlier observations of the recrystallization of pure copper (Hanse. 1981)al t e n.

2. THE SMALL ANGLE NEUTRON SCATTERING FACILITY SANS

The other recently installed instrument is the six meter small angle neutron scattering facility SANS. It was established with support from the Danish and the Swedish Science Research Coun-

289 cils t camI . e into operatio s usen r 198i structurai n fo dd 2an l studies in solid state physics, chemistry, metallurgy and mole- cular biology e facilitTh . s situatei y n experimentaa n i d l hall aa colt d source beam 3 outsidreactoDR e th er confinemene th t a t end of a 20 m neutron guide. A mechanical velocity selector with variable tilt provides monochromatization with AX/\ in the range 0.0o 0.20 t a 5nove s .A l featur e samplth e s placei e n higi d h vacuum (< 10~6 mbar) without windows between the entrance slit and the 40 cm * 40 cm area-sensitive detector. The sample can be rotate d translatean d d automaticall e vacuuth n i my which allows the use of cryostats, cryomagnets and furnaces without introduc- tion of extra windows. The instrument uses neutron wavelengths in the range 4 A to 24 A with momentum transfers in the range o 0.00. t 1 1 0.A~ 3A~ 2

The layout of the instrument is shown in Fig. 5. The main com- ponents are (1) the mechanical velocity selector, (2) the high vacuum collimator tubes ) sampl(3 , e chamber ) fligh(4 , t path and (5) the neutron area-sensitive detector. The instrument

Fig. 5. Layout of the Risa SANS facility: (1) velocity selector; ) collimator(2 ) sampl(3 ; e chamber ) evacuate(4 ; d flight path; (5) area-sensitive detector.

290 has been described in detail by Kjems et al. (1985a) and here only detaile velocitth f o s y selectoe area-sensitivth d an r e detector will be given.

The neutron velocity selector consists of a rotating drum (max. 5000 revolutions per minute) with tilted slits for the passage of neutrons e spectraTh . l properties after passage througe th h monochromato d A\/ an e characterize \) ar r= (A v = 7929/ X x 0 y b d 3168/(vxX), where 9 is the tilt angle in degrees and v is the rotation of the drum in revolutions per minute. For the peak of the col= 500 v d0 d neutrorevolutionan A 3 n 3. fluxr = pe s \ ,

minute e havw , e AX/ n intensita = X0.1 d an 9 f abouo y 10 n-s~t 1

•cm~ e sampl th 2r circula t fo e m diam -8 r d aperturean 6 1 f o s6 a meter, respectively. m area-sensitivc 0 4 x m c e detecto0 Th 4 ea neutros i r n detector and function a proportiona s a s s countega l r . 1985b)(Kjemal t e s . e detecto Th r containinA s m consistga rat 2 d % CC> 5 gf an 2 o s 0.5 atm 3fle. The latter gas is used to produce ionized hydrogen and tritium from the reaction n + ^He •* p + -*H + 754 keV. The electrons froe ionizatioth m n e gastrackth ,n i s drift towarde th s e multipliear anod d an e d neae 64-wirth r e anode gri t +3.a d . 6kV The resulting currents are also picked up by the two parallel coupled cathode grids, each with 64 wires held at a potential of about +1700 V. Both anode and cathode grids are used to determine the position of the above-mentioned neutron reaction impact via e differencth n arrivai e e currenl th time r fo t se endpulsth st a e of the grids. The cathode wires are chosen to have a total delay of 2.4 us (T = RC). The anode grid has small 200Q resistors inter- connecting the wires and giving a similar delay. By measuring the arrival times at each end of the grids the neutron signal can be converte a (x,y o t d ) positio y standarb n d electronic circuitry. e positionaTh l resolutiom fulm 9 l ~ widt s t hali na h f maximum.

A two-parameter Canberra 80 64 * 64 store the x and y coordi- nates correspondin e neutroth o t gn e eventdetectorth n i se Th . two-dimensional intensity spectra can be displayed either as a a three-dimentiona s a contour o p ma r l overview y meana B . f o s PDF 11-23 computer on line with the dual parameter system, it

291

is possible to convert the spectra into (k,ky) space coordi- x nate d thereaftean s o analyst r e dat n th variouei a s wayse Th . compute s alsi r o linkea CAMA o Ct d system which, among other features, control e (x,yth s ) translatio e samplth f o en holder, the velocit e velocity-selectoth f o y e temperaturrth drud an m e of the sample. In addition, the computer is equipped with a 512 * 512 pixel colour graphic screen and a sixteen-colour plotte r graphicafo r l data analysis.

Below the use of SANS in materials science is illustrated by example f receno s t experiments from studie f polymeo s r con- formations and phase separations (2.1.) r aggregation and clus- tering of colloids (2.2.), and magnetic superstructures with very long wavelength modulatio s founa n n cubii d c FeGe (2.3.).

RIS - 0SAN S Ludo n NoCi x I

100 OOM o M 5 07

0 60 M«

0.50 W, «

c c 0 1000 0.4, M 0 c

Q (1/nm)

Fig. 6. SANS profiles for aggregates of silica particles (Ludox, SM) formed in deuterated colloidal suspensions of different salinity which result in different aggregation rates. The spec- e combinear a e spectr Th d . -A fro 4 m2 d measurementan A 2 5. t a s tra are displaced for clarity.

292 2.1. Small angle neutron scattering from polymers

Small angle neutron scattering (SANS) techniqu a particula s i e r useful toor investigatinfo l g physical propertie f polymerso s , since individual macromolecules can be "coloured" simply by ex- change of hydrogen with deuterium. This labelling, which only have minor influence on the physical properties, makes it poss- e moleculeth w ho se se arrangibl o t e e themselve w theho yd an s move among similar or different molecules. Polymer studies at the SANS facilit t Risa y 0 include investigatio f diffusioo n n and relaxation processes, studies of phase diagram and critical phenomen f binaro a y mixture d polymerisatioan s n processen i s membranes. As an example SANS studies of a linear amorphous polymer under stress relaxation is performed. The data shows (Mortensen et al. 1986} that an affine deformation of the in- dividual macromolecules (coils) takes place whee samplth n e is stretched. During the stress relaxation processes the coils first retract and later thev go back toward spherical form. These studies give detailed insigh e coiltth intsw entanglho o e and disentangle from each other.

2.2. Example of small scattering studies of aggregation and clustering of coloids

The recent studies of aggregation and clustering of colloids have introduce w typ ne f structure o ea d s called fractals.

Scattering experiments have turned out to be essential for the study of these structures and for the derivation of structural parameters. Neutron small angle scattering (SANS s complemeni ) - tary to other probes like light and X-ray scattering for struc- tura e lcas th f studiescolloida o en i d an , l silica aggregates to be described below, there is a gratifying accord between the results obtained by the three "light" sources, which when com- bined can span three decades in length scale.

Hexagonal FeGe has the B35 type structure (P6/mmm) and is anti- ferromagneti K wite spin0 th ch41 sbelo= paralle N e T w th o t l c-axis. Below - 57 K the structure changes from a collinear anti

293 ferromagnetic structur a c-axi o t e s double coniferromagnetit an e c structure. The interlayer turn angle for the basal plane component is 194.4° independent of temperature. This corresponds to a repeat distance of ~ 100 A (Bernhard et al. 1984). Cubic FeGe (P2]3, B20) is nearly ferromagnetic belo N (WilkinsoT w . 1976al t e n, Lebech et al. 1986). However, small angle neutron scattering on powdered cubic FeGe (Wilkinso . 1976al t e n) indicated thae magnetith t c structur iferromagnetit an s wa e c wit a verh y long range period- icity similar to that found in the isomorphous MnSi.

Some years s agosuggestewa t ,i d (Ba d Hogkan h Jensen 1980) that the long-range modulated magnetic structures observe n MnSd i d an i cubic FeGe are so-called Dzyaloshinskn spirals. Such spirals may appea n crystai r l structures suc s P21a h 3 lacking inversion sym- metry becaus n instabilita f o ee ferromagneti th f o y c structure with respec o smalt t l "relativistic" spin lattic r spin-spio e n interactions e transitio f s Th firsexpecte.o i e N b tT o t t da n order. The magnetic ordering in a small (~ 1 mm diameter) single crystal of cubic FeGe has been studied using SANS. Illustrative examples of data obtained using incident neutrons of wavelength K onl 0 ye show15.729 backgroun ar t n FigA A i 5n . 7 . d scattering is observed. At 277.6 K magnetic scattering around + Q and -Q = 0.00 1 Q alon( A~ 9 g <100>-directions s observedi )K 8 11 t A . several magnetic satellite e observedar s = , Q fou f t theo a r - m 0.0100 A~^ along <111>-directions - are first order satellites, the others presumably higher order satellites e patterTh . t a n 210 K is observed in the transition region between the high tem- perature magnetic phase (278.7 K > T > 205 K) with the spiral propagation vector along <100>-direction w temperalo e th -d an s ture magneti ) wite K spira th h5 c20 l phas < propagatio T ( e n vector along <111>-directions. Jus te spirabeloth N lT w propa- gates along <100>-directions with a repeat distance of ~ 630 A (Q = 0.0100 A~1). At ~ 205 K the repeat distance increases to = 0.009 Q ( e spira0A th A~1 0 d 70 lan ) propagatio~ n vectors turn towards < 1 11>-directions. In addition to the main satellites higher order satellites develoe temperaturth s a p s decreasedi e . The transition at T = 278.7 K is of first order.

294 1. Small angle neutron scattering data at different tempera- tures obtained from a single crystal of cubic FeGe oriented with the [oil] axis parallel to the incident beam (perpendicular to the drawing plane). The equal intensity contours correspond to , 10050 ,, d 100 20 an 200 00 counts/300s50 , .

The repeat distance observed in cubic FeGe is unusually long - in the related compound MnSi the repeat distance is only 175 A (Q = 0.0359 A~1) - and it has so far been impossible to observe the magnetic scattering in cubic FeGe using conventional neutron scattering instruments. Hence, small angle scatterin s turneha g d out to be a unique tool for studies of nearly ferromagnetic systems.

295 REFERENCES

Avrami, M., J. Chem. Phys. Et, 212 (1940).

Bak, P. and Hogh Jensen, M., J. Phys. C 1_3, L881 (1980).

Bernhard, J., Lebech, B. and Beckman, O., J. Phys. F 14, 2379 ( 1984) .

Broholm . ThesisC , , Technical Universit f Denmarko y , Lyngby, Denmark (1985).

Bunge, H.J., Proceedingh Internationa7t e th f o s l Conference n "Textureo d Materialsan s " (Noordwijkerhou t, 1984 ) Zwijndrecht, 7 (1984)44 .

Felcher, G.P., Jorgensen, J\. D. and Wäppling, R. , J. Phys. C 16, 6281 (1983).

Fischer, P., Lebech, B., Meier, G., Rainford, B.D. and Vogt, O., J. Phys. C JM_, 345 ( 1978) .

Freltoft, T. and Kjems, J.K., to be published (1986b).

Freltoft , KjemsT. , , J.K d Sinha.an , S.K.,"Power-law correlations and finite size effect n silici s a particle aggregates studiey b d small angle neutron scattering (SANS)", submitte o Physt d . Rev.B ( 1986a).

Fruchart, D., Malaman, B., Le Caër, G. and Roques, B., Phys. Status Solidi a 7_8, 555 (1983).

Grant , JuuE. ,l Jensen d , HansenRalphan D. , , . ProceedingB ,N. , s of the 7th International Conference on "Textures of Materials" (Noordwijkerhout, 1984) Zwijndrecht 9 (1984)23 , .

Juul Jensen, D., Hansen, N. and Humphreys, F.J. "Texture Devel- opment during Recrystallization of Aluminium containing Large Particles" e publisheb o t , n Acti d a Metall. (1985).

296 Juul Jensen, D. and K^ems, J.K., Textures and Microstructures _5_, 239 ( 1983) .

Hansen, N., Lefters, T. and Kjems, J.K., Acta Metall. 29, 1523 ( 1981 ) .

Kjems, J.K., Bauer , BreitingR. ,d Thuesen an . B , ,Proceeding A. , s of "Neutron Scattering in the Nineties", (Jülich, IAEA, 1985) 489 (1985b) .

Kjems, J.K., Bauer Christensen, R. , , FreltoftP. , , JensenT. , , L.G. and Linderholm, J., Proceedings of "Neutron Scattering in the Nine- ties", Jülich, IAEA, 1985 5 (1985a))49 .

Lebech , BernhardB. , publishee d Freltoftb an o t . J , , dT. , (1986).

Lebech, B., Broholm, C., Clausen, K. and Vogt, 0., to be published in the proceedings of "The International Conference on Magnetism" (San Francisco, 1985) (1986).

Lebech, B., Clausen, K. and Vogt, 0., J. Phys. C 13, 1725 (1980).

Mandelbrot, B.B., "The Fractal Geometry of Nature" (Freeman, San Francisco, 1983).

Meier , FischerG. , , Hälg , Lebech,W. , RainfordB. , , B.Dd an . Vogt, 0., J. Phys. C 11, 1173 (1978).

Mortensen , KramerK. , , BatzberO. , g Pedersen d Fettersan . W , , L.J., e publishetb o d (1986).

Schaefer, D.W., Martin, J.E., Wiltzius, P. and Cannel, D.S., Phys. Rev. Lett. ^L, 2371 (1984).

Rossat-Mignod, J., Burlet, P., Villain, J., Bartholin, W., Tcheng-Si, W. , Florence, D. and Vogt, O., Phys. Rev. BJ_6 , 440, (1977).

Wilkinson Sinclair, . C ,d Forsyth an . F , , J.B. h Internationa5t , l Conferenc n "Solio e d Compound f Transitioo s n Elements". Extended Abstract 1976( 8 . ) 15 p s

297 RESEARCH REACTOR AS A TOOL FOR RESEARCH IN PHYSICS

K.R. RAO, B.A. DASANNACHARYA Nuclear Physics Division, Bhabha Atomic Research Centre, Trombay, Bombay, India

Abstract Thermal neutrons trom research reactors have been used during the past three decade n studiei s t variouo s s aspect t condenseo s d matter physics and nuclear physics. At Trombay, the CIRUS Reactor has been extensively used in basic and applied studies. The paper reviews neutron scattering and radiographie work done with CIRUS and APSARA reactors. This will include result n structuro s d dynamican e f amino-acidso s , spins-structure t territeso s , texture studie n uraniumo s , particle size/grain boundary measurement in beryllium, photon studies in terroelectrics. etc.

DHRUVA e latesth , t Research Reacto t Trombaya r e ,highes th wil e b l t neutron tlux facility (nearl x lO ^2 y n/cm^-sec n Indii ) a whet i n

becomes critica e neath rn i lfuture e desige reactoth Th f .o n r pile 1 bloc s beeha kn incorporated with recessed cavitie d cut-awayan s s that allow the experimenters to approach closer to the source.

Severa spectrometerw ne l e undear s r fabricatio r installationfo n . In orde o increast r e through-putth e , multiple detectors, posit ion-sensitive detectors, tocussing monochromator a MAR d Xan s analyzer are incorporated in these spectrometers. The spectrometers will all be automated for control, data acquisition and processing using microcomputers. The paper will also describe the facilities being installed at DHRUVA and the planned experimental programme.

I. INTRODUCTION

Research reactors with 0 e fluxerang1 th f o n ei s 0 1 neutrona/c o t m -sec have been user nearlfo d y three decades in the study of physics of solids and liquids, nuclear physics and for various applications including isotope production, neutron radiography, neutron activa- tion etc. In thia paper wa shall review how the reactor faci- lities at Bhabha Atomic Research Centre, Trombay have been utilise s importana d t tool n Basii s c research per- taining to condensed matter physica and in a few applied . ta as c pe

299 Most of the work rsviewsd in this paper has been carried out using the Cirua reactor at Trombay which ha* successfully completed twenty five years of uninterrupted operation providing thermal neutron flux of 6 x 10 nsutrons/ cm -sec at 40 MW. A swimming pool reactor Apsara with 12 2 flux of nearly 1U neutrons/cm -SBC at 400 K.V has been user neutrofo d n radiography. Short lived isotopoe ar s also produced at Apaara whereas a rabbit facility for neutron activation exists at Cirus,

• ** Nautron Scattering Facilitie t a Cirus s Thermal neutron e usefuar s l probes s i wel s a l , known, for studying structure and dynamics of solids and liquids. Neutron Crystallography, magnetic diffraction and in- elastic neutron scattering techniques have been user fo d this purpose.

Several neutron spectrometers have bee n operatioi n n at Cirus for nearly two decades. Specifically, a full ) (i y automated single crystal diff ractometer permits o stud f crystao y l structur t a nearl, a usin A 1 yg single crystal samples mounted in a four-circle goniometer. An on-line computer is used for collacting single crystal data from various reflections. A low temperature cryo-tip is also available for making measurements down to 100K. (ii a conventiona) l triple axis spectrometer fo r stud f phononso y on-linn A . s microcomputer providsg mean o studt s y phonon intensitie n constant-Q/i s E modes. (iii) a polarised nsutron diffractometer allows study of magnetic specimens 3 magnetihel n i d c field o using polari««d neutrons of wavelength nearly 1A. (iv a hig) h resolution powder diffractometa r studfo r y of texture. a powde ) (v r diffractomete r magnetifo r c studies (vi) a medium resolution triple axis spectrometer with pyrolytic graphite monochromate d analysean r r fo r quasi-elasti d inelastian c c étudias.

300 (vila rotatin) g crystal spectrometer allow a higs h resolution inelastic neutron scattering study from liquids and powders. Using a filtered cold neutron beam e rotatinth , g monochrom i sslacteto a narroa w o ban f neutrono d e pulseth s d daroun an beaA a i 4 md scattered from the sample. The spectra of scattered neutron s analysesi y tima-of-flighb d t technique using a flight path of 3 maters and several detector banks. III. Some Important Investigations carried out at Cirue As already e facilitiepointeth t ou d t Cirua s s have been e fieldusefuth f neutron o si l n crystallography, magnetic diffraction and inelastic neutron scattering. In this short paper we will only quote a few of our recent investigations as typical examples of how a reactor source is useful for basic research in condensed matte hysip r . cs

) Neutroa ( n Crystallography

5tudy of structure of biologically important molecules like aminoacids, nucleotides, bipeptides and investigation of nature of hydrogen bond in various systems war e easpect th som f o e s coveree Trombath y b dy grou r severafo p l years. Recently stud f phaso y e tran- sition n othei s e subjectr th system f o s beese ha son n f investigationso e shalW . l n example^studquota s a e y of LiKSO^ a system in which laser Raman scattering and lattice dynamical studies have also been carried t Trombaya t ou .

LiKS04 exhibits several successive phase transi- tions e naturTh e mechania.f phaseo th e d an sf o m phose transitions is only recently being understood. Using thermal neutron diffraction technique, temperature dependence of intensity of a number of Bragg peaka of LiKSO, have been studied £TJ7. Fig.1 shows typically e reflectionthth e f behaviouo a functioe s on e s f o rf o n temperature. It is observed that the crystal undergoes sluggish phase transitions which is quite complex in

301 (110)

SlOW HCATMO

SO MO IM TOO 300

Fig. 1. Variation of Bragg intensity of one of the reflection f LiKSOo «a functio s a ^ f temperaturto n .

the coolin d heatinan g g cycles. From detailed analysis of the diffraction data a9 a function of temperature it is observed that the kinetics of the phasa transition depends an the thermal treatment of the crystal. ) Magneti(b c diffraction The magnetic structure studies of several forritei, mixed ferrites, Heusler alloyse etcth o t . havd le e determination of magnetic structure and spin density distribution of a very large number of euch systems n recenearlieI . t on ryears , emphasi s shifteha s d to stud f diluto y e magnetic system d systeman s s wherein small variations in concentrations of constituents result n fairli s y large variation n magnetii s c density distributions. As an example,we quote results from a recent study of NiRu alloy /?_7. Fig.2 show e magnetith s c spin density distribution derive a serie n i df Ni-fl o s u y noticalloysma e oOn . that as the concentration of RU is varied over a narrow

302 Atom

Fig 2. Magnetic moment dittribution in Rux.

303 rang f concentrationso e a magnetith , c density distribution varies considerably. These studies have shown that within the narrow range of 2-4$ of "flu variation, aephericity of host moment increases and then decreases with increasing Ru contant. Similarly reversa U momenR f o lo t t froe -v m +ve moment ia alao observed in this concentration ranga. ) Inelasti(c c Neutron Scattering from Phonons Although Cirue w flureactolo xa reactos i r r fo r inelastic scattering studies s beeha n t i possibl, o t e investigate a few systems quite thoroughly. One of the- moat complex systems studied was ot-KNO^ containing 4 molécule r unipe st cel w frequencllo f3_7»e Th y acoustic w opticafe a mode d l an branches s measured along thrss high symmetry directions were helpfu o analyst l s th s system withi e frameworth n f rigio k d 'molecular n modalio 1 . In recent years we studied the inelastic scattering s fro a mineral-stibnita(Sbm 2 3>whic a ferroelectri s i h c semiconductor. Ths résolution of the instrument permitted us to observe only diffuse scattering from this system extended in a plane perpendicular to tha chain-axis of e systeth s showa m n Fig.3i n . Detailed lattice dynemical studies /T 7 have revealed that ths very low frequency transverse modes of the lattice may give rise to diffuse scattering and secondly a phase transition in the system may result in inter-chain disorder. (iv) quasi-Elastic Scattering Studies Quasi elastic scattering of neutrons is, in a certain sense, a unique wa,y of studying stochastic motions in that it gives information not only on the rate of tha character- istic motions but also identifies the geometry or the path taken by the randomly moving molecule. First of such measurements at Trombay were made on liquid CH^/S 7 and ware used to demonstrate that the rotational motions in liquid methane were hindered. These measurements were quantified later using the theory of Seara. Further mea- surements on liquid NH-, were used to derive the first order angular correlation function.

304 Diffuse 'cl.isiic' Intensity around (040) lattice point, (i) The K*M »tons , correspondin0 JlfTereno t g ; op«t 0 Q,s. n- , ) ScacirckQ (b nr »alonfo , gQ correspond in A.' « 4 layer datn of figure J for compariion. The irnei m ihc middle show» in elllpilcal coniour corresporKÜng to the 'btie> width' of M il-- ni (.>) Noie iliat. ihc cllirno i> extended beyond (140) along t/c «nd It» width alung ihc 6-a\is is only about 10% of 1/d (010)

U.4,0) (3.5,4,0)

(^3.5,0)

Fig. 3. Diffusa scattering from SbjS-j. The long axia of the ieointenaity contour ia in a plana parpandicular e chaitth o n axia.

305 0 1 " 0 "7 0 1 0.1 T s.rI 4 - »)/A(I '' A

form facto f NH^ o rt rooa I m températuree Th . lines (a) to (h) correspond to various models discusse n referenci d . 7 > /? e

Reorientational motions in several molecular solids

like (NH4)2 SD4, (NH4)2 flaF4)NH4LiS04, Mixed salts of

(NH) S0 and KS0, NHBr,NHI and Mixed salts of NH 4 2 4 2 4 4 4 4 d K(Br,Ian (Br ) ,I ) have also been studied n solideI . , the near elastic scattering can be divided into a truly elastic part and a quasi elastic part« The ratio of the elastic scattering to the total (near elastic) scattering gives informatio e geometrth n o nf jumo y p reorientation«

Fig.4 show e resultth s r NH t fo roos4a I m temperature along with several model calculations consistant with geometrical requirements. Rotational diffusio d octaan n - hedral jump models are in agreement with the experimental points. However e basith f diffractioo n s o , d inelastian n c scattering data these models also have beed n an rule t ou d w modene a l propose r sucfo d h system. 7 £ \f s

e experimentaTh l studies outlined above have also been backed by appropriate theoretical investigations and these have led to important conclusions regarding atomic wave functions in magnetic systems, the nature of bonding and structure in solids, mechanisms of re- orientations in molecular solids and nature of phase transitions.

306 (v) Development of New Techniques

Cirua reacto s alsha r o been usefu n studi ld an y developmnn w techniquene f o t r neutrofo s n scattering, e hrwW e studie e potentialitieth d f window-filteo s r spectrometer for phonon measûrement s, whîie beam diff- raction, small angle scatterin d higan g h résolution inelastic 3 pectrometry. Wa shall discuss some salient features of the last one of these,namely,high resolu- tion inelastic apectrometry, which is of great import- . us anc o t e e havW e obssrvsd experimentally that wheo tw n filters of the same material like Be are maintained.at unequal temperatures, the temperature difference being, e neutronth , sayAT ,s transmi d througtte e firsth h t filte n selectivelca r e backscnttoreb y d froe seconth m d filter within an energy speed of AE. AE, a function of AT, is identically zero when AT =» 0.. Hence as one uses small AE or AT-window,small energy loss processes e observeb n ca d using this principle n instrumenA . t buil n thio t s principl n providca e e resolutiona f o s few tens of ^LeV at around a 5.2 meV when two beryllium filter e maintainear s y 100 sa d 300K Kt an a d .

A high resolution spectromete re abovbaseth n eo d principle has been designed /T 7 and built recently at Trombay end installed at the SNS, RAL-UK. Fig.5 shows the schematic e instrumentlayouth f o t . Fig.6 showe th s time-of-flight observation of the AT-window using the SN5 facility. Similarl e havw y e used Apsara reacto r testinfo r g r neutroou n r neutromirrorfo d an ns rediogrephy.

. NeutroIV n Facilitie t Dhruva s e DHRUVA e latesth , t rsssarch reacto t Trombaya r , became criticel on B August 1985. It is a natural uranium, heavy water moderated, heavy water cooled reactore maxith t -A .

307 Be-n

T2 '300,500 K 1 , 0 I 1 K [ t X /\- \ i L \ DETECTOR , J-!T PU£L ' 1 — Be-I K 0 10 « T ,- :: 1 1

X (E0-E)

Fig.5, Schematic layou f /iT-windoo t w spectromater installed at SNS at RAL, UK.

N E U T R 0 N

C 0 U N T S

m i c n o 3

O n d 32.8 33.0 33.2 33.4 33.6 33.8 cr-oL m ( s econdE H Tl s)

Fig. Resolution of A T-window apactrometer aa measurad at 5N5.

308 reactoe muth m rate, r MW wil d0 powel10 providf o r • e flux of 1.6 x 10 neutrons/cm -aec. The reactor is designed with several features appropriat r neutrofo e n beam research of condensed matter. The reactor pile bloc s incorporatei k d with recessed cavities and cut-aways that allow the experimenters to approach closer to the source. With the help of tangential beam holes and through-tubes the fast neutron and Y-rsy backgroun s soughi e dreducedb o t t A col. d source based n liquio dt graphit ho methan a d ean e moderator block will remoderat e neutronth e o providt s e cold epithermaan d l neutron fluxes o guidTw . e tubes will make available cold neutron booms with A\ * equal to 2.2 °A and 3 A° in an ad- joining laboratory to carry out experiments in low background conditions. Becaus f theso e e in-built features e rasctoth , r will serve aa a powerful neutron source for materials reeearch and an overall gain by factors of 5-10 is expected ove a conventionar l reacto f similao r r flux. Fig.7 shows th s schematic view of the experimental facilities for neutron beam research that are planned for this reactor.

Several new spectrometers are under fabrication r installationfo . The ya profil are) (i j e analysis powder diffractomstar (ii) a single crystal diffracto- metar (iii) a medium resolution inelastic spectrometer (iv) a polarised neutron spectrometer with analysing capability (v) a filter detector spectrometer (vi) a high resolution inelastic spectromete a doubla n o r - monochromator (vii) a small angle- scattering spectro- meter and (viii) a neutron interferometer. In order o increast e through-putth e , multiple detectors, posi- tion-sensitive detectors, focusaing monochromatord an s a MARX analyse e incorporatear r n thesi d e spectrometers suitably. The spectrometers will all be automated for control, data acquisitio d processinan n g using micro- computers which form a part of a larger network of other mainframe computers. Prototype spectrometers, controls and other systems have been tested.

309 OJ o POlA.WSAT10NAHW.rSlS 4-ORCI_ __ E NEUTRON SPECTROCTER CXFFRACTDKETER NEUTRON INTERTEROÇTER

TR1PU AXIS SPECTROMETER

HGH RESOLUTION SPtCTROiETER TRIPLE AXIS SPEC TRC METER ROTA TING CRrSTAl HOHMA GtJTTK XTTCT5 SPEaROMETER SOi/OSIN BffQAXHJNOUH£ STUCIESÛF PAHOCHIN UQUIOS AMD MOTIONS QÜA3 ELASTIC SPtCTROMETTR s Too+snc no r IONS W VOCf CX'LAf 5TSTEXS OWOS •OUWrSED NEUTRON D'fTR ACTD METER GUIDE-TUBE LABORATORY

ALSHArm AMD (.BUDS srmxrnjtf

REACTOR HALL

Fig.7. Schematic view of experimental facilities at Dhruva. . V Experj.msntal Programm t ühruva e a

The facilitie t ühruva s a will provid s witu e h fluxes t samplea s greate n ordea y f magnitudb o r e compareo t d

thos3 at Cirua. We believeftherefore1that we can undertake entirel w typene yf investigationo a s whic e coulw ht no d undertake till now. Amongst these we plan to carry out structural studies of systems containing upto 100 atome per jnit cell. The profile analysis spectrometer would be usefu t onl n no lroutini y e analysi f variouo s s samples but to monitor phase transitions as a function of tempera- tur r pressureo e . Stud f phaso y e transitio n magnetii n c and non-magnetic systems would be a major activity via magnetic diffractio a inelasti s vi wela ns a l c neutron scattering studies. Soft mode spectroscopy, studf o y enharmonic effects in ssmi-rigid solids and high resolu- tion quasi-elastic scattering will be of interest using the inelastic scattering spectrometer t Dhruvasa . Topo- graph d smalan y l angle scattering studies from metallur- gica d biologicaan l l materialw ne s e wil th e som b lf o e areas where we will take up investigations. The hot source would help us in carrying out chemical spectro- scopy. -Ve have already identified a few systems where the first experimente th ?l wilal e focusses b lA . on d spectrometers wil e coupleb l a fairl o t d y powerful computer e microcomputeth a vi t wor t ne shoulri k e possiblb d o t e increase the quality and quantity of the throughput.

Acknowladgemen ta

The experimental programme at Cirus and Dhruva have e imprint^supporhath d d kinan t d encouragement from Dr.P.K. lyengar, Director of our Centre. ThB planning e severath f o l instrument t Dhruva s a took shape under the supervision of late Dr.N.S. Satya Murthy. We ere grateful to several of our colleagues whose experimental results we have quoted in this paper.

311 References

I.Sandhya Bhakay-Tamhane,A.Seqeir d R.Chidambaraan a m Solid Steto Comn ,193 _5 . 7 (1985) 2.R.Chakravarthy,L.Madhav d N.S.Satyan o Ra a a Murthy Pramana _1J5 ,207 (1980) 3.K.R.Rao,S.L.Chaplot,P.K.Iyengar,A,H,VenkatB8h and P.R.Vijayaraghavan Pramana 11 ,252 (1978) 4.K.R.Rao,S.L.Chaplot,V.M.Padmanabhan and P.R.Vijaya- raghavan Praman ? ,59Jj a J (1982) 5.B.A.Daaannachary d G.Venkataramaan a n Phys.Rev.,156, 43 (1967) o.P.S.Goyal and B.A.Uaaannacharya J.Phya.C iSolid Stata Phya., j_2 ,219 (1979) 7.B.A.Daaannacharya,P.S.Goyal,P.K.I yengar,N.S.SatyaMurthy, J.N.Son d C.L.Thapaan i r Paper IAEA-CN-46/025n i P Neutron Scatterin e 'Ninetieth n i g s IAEA,Vienna p443 (1985)

312 THREE GENERATION NEUTROF SO N TRANSMUTATION DOPING OF SILICON AT RIS0 NATIONAL LABORATORY

. ANDRESENK . HEYDORNK , . HANSEK , N Isotope Division, Ris0 National Laboratory. Roskilde, Denmark

Abstract

The first commercial irradiatio f silicoo n s performewa n t a Rise}d ) in April 1974 tor the Danish company Topsil. The 1-2 inches silicon crystals were irradiated in an aluminum can in a horizontal graphite stringer in the thermal column of reactor DR 2.

While the demand tor NTD-silicon was growing, it was decided to close down the reactor DR 2, and construction of an irradiation facility n reactoi 3 becam R D r e necessary.

Reactor DR 3 is a 10 MW heavy water cooled and moderated research reactor n SeptembeI . r 197 3 inc5 a h silicon irradiation facilits wa y e graphitth n i installe 3 eR reflectoD n i d a vertica n i r l tube wita h . mm diamete 0 10 f o r

n 197I 7 four more facilities were installe e graphitth n i d e reflector in DR 3.

Quality contro s madi l placiny b e g cobal te irradiatiowireth n i s n measurd an cane , th Co-activite o verift y y that each batch gete th s 60 right neutron tluence.

In 1980 it was decided to construct a new irradiation facility to be place a vertica n i d e lheav th tub n yi e water tan r irradiatinto k o t p u g 4 inch crystals.

incA o h tw facilitie w no Ther e n operatioar i es n after initial problems have been solved.

INTRODUCTION

This report describes the development of facilities for neutron transmutation dopin f silicoo g n durin e lasn yearsth gte t .

Irradiatio f silicoo n n single crystals with both thermad an l fast neutrons for scientific research began at Ris0 National Laboratory in 1960 immediately after start-up of the Danish reacto . 2 Thi R D s r 5 Mreacto Wa tank-typs wa r e light-water reactor wit a graphith e thermal columnn 197i e d firs4th an , t

313 industrial productio " diamete2 f o n ~ siliconT r s carriewa * d out in co-operation with the Danish company Topsil in Frede- rikssund.

I2 reacton R 197 D s close e wa r5 th d a novedown d an l, facility s designewa d specificall e irradiatioth r fo y f silicoo n n crys- tals with 3" diameter and installed in the Danish reactor DR 3, whica heavy-wate s i h r reactor . operatinCommerciaMW 0 1 t a g l production gained momentum during n 1971976i d 7 an additiona, l irradiation facilities were constructed and installed in the DR 3's graphite reflector. e fasTh t growing marke r NTD-silicofo t n mad t desirabli e o t e construct a new facility to be placed in the heavy water tank of DR 3 for irradiation of up to 4" silicon crystals. The high pric f heavo e y water user coolinfo d d transportatioan g n made it necessary to install a storage facility designed for recovery of heavy water.

Irradiation in the thermal column of PR 2

The first commercial irradiation of silicon was performed at Ris n aprin reactoi i 0 2 l e DanisR D 197rth r 4hfo Company TOPSIL tor, operatin 7 hour r 5 dayfo sg a weeks . Irradiation" 2 f o s silicon were performed in aluminium cans of 53 mm 0 in a hori- zontal graphite stringer in the thermal column, shown in Fig. 1.

Fig Graphit. 1 . e stringe r irradiatiofo r " diamete2 f o n r silicon crystal n Danisi s h reacto. 2 R D r

*Registered trade mark.

314 Ove a rlengt f graphito h f approximatelo e 6 cylindrica m m 0 52 y l holes of 58 mm 0 were drilled in such positions that all received the same total neutron fluence when reversed afte e expiratioth r n f halo e irradiatioth f n time.

Only 80 mm length of crystals could be irradiated in a single position, corresponding to a volume of 0.18 dm^ or 1.08 dm^ per stringer. This facility was supplemented in 1975 with another stringer with only 4 holes, which permitted irradiation of crys- tals up to 71.5 mm 0 and a total volume of 1.33 dm^ per stringer.

Until the final shut-down of DR 2 by November 1, 1975, a total of 100 kg silicon had been irradiated in these facilities.

Irradiatio " diamete3 f o n r 3 silico R P n i n

When the decision to close down the reactor DR 2 was made, the demand for NTD-silicon was rapidly growing, and design and con- structio a silico f o n n irradiation facilit n reactoi y 3 R D r seemed necessary.

The Danish reactor DR 3 is a PLUTO-type material testing reactor, cooled and moderated with heavy water and fueled with 93% en- riched uranium. The normal reactor operating schedule is based on a 4 week-cycle with 23 days of continuous operation followed by 5 days shut-down.

A vertical sectioe reactoth f s o showni r n Figi n .2 illustratin g e positio e th verticath f o n l irradiatio ne graphittubeth n i s e reflector relativ e reactoth o t er core e 4VGTh . R tube hava e diameter of 100 mm, and the maximum thermal neutron flux density x is approx. 4 lO^n/tm^ S) at a power level of 10 MW.

The temperature of the graphite reflector is about 185°C, and the maximum heat generation from Y-radiation is approx. 20 W/kg of aluminium.

315 E«Denmeniat rxxen s

fue' element rv —— —

4V

Fig. 2. Vertical section of the Danish reacfoi OR 3, showing various irradiation facilitie e reactoth d an rs core e diameteTh . r e heavth f yo . watecm 0 r 20 tan s i k

A schematic drawinq of the irradiation rig designed for the neutron transmutation doping of silicon crystals with a diameter up to 78 mm or 3 inches is shown in Fig. 3. Crystals with a total e irradiateb n ca m n aluminium i d 0 59 lengto t m p canu h s wita h

wal l, correspondinthicknesmm 5 0. f a volumo s o t gf 2.8 o e 2

n The spaji^al^ ^L^^i.!!0 ^ neutron flux density within the irradia- tion volum f almoso e 3 litert s assymeti s d exceedan r% ica50 s l. The effect of the radial flux gradient is, however, practically eliminated by rotating the irradiation container at approx. 2 revolutions per minute during the entire irradiation period.

The vertical flux variation along the axis of rotation is de- picted in Fig. 4, and its effect is reduced by the installation f gradeo d absorber f stainleso s s steel aroun e positioth d f o n maximum flux y reducinB . e peath gk neutron flu o approxt x .

3 * 10^n/(m2 e variatioth s i reducen - a facto al y b f d o r most 2 over the 500-mm length of the absorber, as can be seen in the figure. The vertical flux profile, however, changes in

316 the course of the reactor period within the shaded area between e firslasd th an tt flux distribution.

2550 r mm

Shield plug Handling flask Crysta— l container Reactor topfloor Steel shield ' / S /t Topvoid

Topshield iatiog nri

Rotating tube

Crystal container 2562 2913 3001

Fig. 3. Rig for the irradiation of 3" silicon crystals in a 100-mm 0 vertical irradiation tube in the DR 3 qraphite re- flector.

mm height above detector ^ 800.

O ^ N>»J700>V-

600<

500-

AOO-

300-

200-

inn.

- 0 -1 5 -1 0 -2 -.oo

-200

Fig . Axia4 . l variatio f neutroo n n flux den.sity befor d aftean e r installation of stainless steel absorbers. During an operatinq period the flux distribution varies within the shaded area.

317 A shielded handling flask is used for loading operations in the rig and the storage facility and for transfer operations between the rig and the storage facility. The flask is moved by a small wagon driven by a geared electric motor and the shield is formed a cylindrica s a l jacket wit a thickneshm leadc 2 1 . f o s

The reactor top plug and the irradiation can are lifted by means a pneumaticall f o y activated grab during loading operationse Th . grab receives compressed air through a reinforced rubberhose, whic s alsi h o a ropeuse s a d, whee gra th s nlifte i ba winc y b dh e flaskth f o . o to e placeth n o d

Reactor power level is usually kept constant to within 1% during the entir 3 day2 ef operationo s . However, this doet meano s n that the neutron flux density in a particular irradiation posi- tion remains constant. Changes in fuel element configuration, burn-up, control rod position, as well as the presence of other experiments in the reactor, result not only in changes from one operating e nextperio th t als bu o ,t od durin e coursa th g f o e single period.

This t^empora_l_va_ri^at^ion necessitates continuous flux monitoring in orde o controt r e neutroth l n transmutation doping with suf- ficient accuracy. Thi s achievei s d wit a detectoh ] base[l r n o d

a measuremen e heath tf o "?Lt) produce a i e f reactio , th n ( y B b d^ ^ n d showan n Figi n. 5 .

A small Boral disc is mounted in a stainless steel capsule in y sucwa ha thae heath tt generate y neutrob d n absorptio s coni n - e surroundingducteth o t d a 5-m a 0 steem vi s l rod e temperaTh . - ture differenc s measurei d e ro betweey b de th e end th f no s chromel/alumel thermocouples and is proportional to the neutron flux density. The thermocouple signal is converted to a fre- quency of pulses, and the number of pulses recorded is a measure of the thermal neutron fluence. The detector is located in the e rotatinbottoth f o m g tub ee irradiatioclosth o t e n cans a , indicate n Figi d. 3 .

e calorimetriTh c e calibratedosimeteb o t a knows n ha ri d n neu- tron flux densitys calibratioit d an , n shoul e checkeb d d under

318 Thermocouple

Bora- , l

Stainless steel

Fig. 5. Calorimetric thermal neutron flux detector. A Boral disc 15 mm 0 is mounted in a 26 mm 0 stainless steel capsule f totao . lmm lengt0 3 f o h

different, prevailing reactor conditions. This calibration is performed by means of neutron fluence monitors of cobalt wire.

n 197I 4 additiona7 l facilities were installe e graphitth n i d e reflector in DR 3, and it became necessary to construct a special storage facility with heavy lead shielding.

A considerable effor d beeha te design th mad n f thesi o ne- fa e cilitie o ascertait s n accurata n e contro f neutroo l n doseo s , that NTD silicon semiconductors could be produced to close tolerances Results from more then yearte nf continuao s l operation indicate that deviations from the nominal value on a routine basis have a standard deviation of less than 5%.

Irradiation of 4" diameter of silicon

In 1980 the demand for more NTD-silicon with larger diameters prompted us to design a new irradiation facility to be placed in a vertical tube near the fuel elements in the heavy water tank , showd Fig3 . 6 an n FigR . i D n2 . f o

319 Coarse control arms

Storage holes

Fig. 6. Horizontal cross section of the Danish reactor DR 3 showing positio f experimentao n l facilities relative th o t e reactor 4 corefacilit e 7V distanc Th e . th y f o efroe centrth m e of the core is "700 mm.

The rig is designed for irradiation of silicon crystals of a e thermaTh . mm l 0 neu40 d lengt-o t an p m u m h 7 diamete10 o t p u r tron flux, smoothe n absorbea y b d r screen^ 10 s abou i ,* 2 t n/m^s and the Y-heat in the irradiation zone is about 250 W/kg. With crystals weighing 5 kg or more, it is necessary to cool the silicon crystals during irradiation.

Fillin e tubth ge with light water depresse e thermath s l neutron flux by a factor of approximately 5, while heavy water caused a slight increase of about 25%. In spite of the high cost it was decide 4 tub7V o efile t d witth l h heav ye temperawaterth d an ,- e crystalth tur f o e s during irradiatio s onli n y about 50°C.

In the irradiation zone of the 7V facility the variation of the incident thermal neutron flux is about 20% in axial direction and about 25% in radial direction.

320 e unirradiateTh d crystal e loade a thiar s n i nd walled (0.) 5mm irradiatio n madca n e from A1-2S e insid.Th e diamete e conth -f o r , correspondinmm 5 e lengt40 th s d a i h an o t m gm 0 taine11 s i r volume of 3.59 dm^. During irradiation the container is placed e e rotatinbottoth th f t o a m g aluminum tube, whic s supportei h d a graphit d an a bal p y b elto bedrinbearine e th th t t a a g middle.

The tube is rotated at a constant speed of 2 rpm by means of a geared electric motor placed at the top of the rig. The rotating tub s surroundei eg thimble ri a y b ,d which acr s containmena s t for the heavy water in the rig. The rig has a top shield made from stainless steel with channele heavth yr fo wates r flow used to transport the container up from the rig. A lead filled stainles e rotatinth s f steeo gp l to tubeplu e s placei gth . n i d During loading operation e plu s th removesi g d storean d d inside e handlinth g flask.

A stainless steel absorber is mounted on the outside of the rig thimbl n ordei e o equalizt r e verticath e l flux variationd an , the optimum shape of the absorber is found from a combination of actual experiments and calculation on a theoretical model of the reactor [4].

When the irradiation of the crystal is finished one of the main pum s startei p a signa y b d l froe fluth m x - integratoin e th n i r strumentation e heavTh . y water flows circulatin p througu g e th h rotatin e rigth .f o g p tubd forceto an e e e containeth th s o t p u r The water flow is about 4.5 m^/h and the gap between the con- tainer and the tube is 1.5 mm.

The container is stopped by the shield plug at the top of the rig. The transport time from bottom to top is 1-1.5 minutes. The container is then left to decay for about 30 minutes at the top of the rig. The main pump is stopped when the irradiated con- tainer is removed to the handling flask and an unirradiated e rigth .f containeo p to e s placei rth n i d

When the main pump is stopped, the container will sink down in the rotating tubd reac e an bottoe th h m after 0.5-3 minute- de s pending on the crystal weight. 321 e shieldeTh d handling flas s user i loadink fo d g operationn i s e storagth n i e d facilitr an transfe fo g d ri an e y rth operations between the rig and the storage facility.

e flasTh s movea smali k y b dl wagon operate y meanb a d f o s geared electric motor. The shield is formed as ^ cylindrical jacket with a thickness of 12 cm lead. A drum with a loading g plug holri d positionn irradiate a an ,e e th r fo s d container and an unirradiated container is placed inside the jacket.

e reactoe irradiatioTh th p plud to ran g n container e liftear s d a pneumaticall y b y activated grab during loading operations. The grab is supplied with compressed air through a reinforced rubber hose, which also is used as rope when the grab is lifted e flaskth f .o winca p y b to h e placeth n o d

By means of an indication valve it is possible to control when the plug or a container are correctly placed in the grab. The order of the single operations are controlled by a special guide e flaskth f .o disp to c e placeth n o d

After irradiatio s necessari t i n o plact ye container th e a n i s shielded storage facility 3-5 days before they can be handled without shielding. The duration is determined by the ^^Ga im- e aluminiupuritth e containersn th i y f o m .

The storage facility consists of 85 stainless steel tubes ar- range n fivi d e rowd shieldean s y leab d d walls.

e storagth f o e p facilitto n levee i Th s li y wite reactoth h r top. Loading operations are made by means of the handling flask, which can be moved on the reactor top between the rig and the storage positions.

t containerwe e e storagTh e drieth ar sn i de facilit y meanb y f o s heate r circulateai d d throug e tubesth he evaporateTh . d heavy wate s recoverei r a condenser n i d .

322 e caloriTh c dosimeter would buro rapidlto n n thii y s facility, e thermath d an l neutron flu s therefori x e measure y threb d e self-powered neutron detectors of the vanadium type placed in guide tubes in the irradiation zone of the rig.

The signal from one of the neutron detectors is "-onnected to an analog-to-digital converter, which integrate y meanb a sfre f o s- quency proportional to the signal from the neutron detector. Be- fore irradiatio a predetermine e integratot a th n t se s i r d value.

Quality control is made by placing cobalt wires in the irradia- tion can, and measure the 6Cn o _ activity to verify that every batch get the right neutron fluence. The axial variation over the 400 mm length of the crystal is - 8%.

In 1983 an additional facility was installed, and both facili- n continuoui w no tiee sar s operation.

Conclus ions

Facilitie r neutrofo s n transmutation dopin f silicoo g t Risa n 0 have developed from small quantities of 2" crystals to large quantitie " crystal4 f o s s ove a perior f leso d s tha a decaden .

e irradiateTh d silico s deliverei n o Danisht d ,- GermaJa d an n panese customers, and the increase in the volume of production is illustrated in Fig. 7.

b J3 83 ;i'j

_T_.A decad f NTD-silicoo e n productio t Risa n « National Laboratory.

323 Experimental quantitie " silico5 f o s n crystalw beinno e g ar s produced, and new irradiation facilities may have to be con- structed in the near future.

REFERENCES

[1J HAACK . Ris0-M-224K , 7 (1980). [2] HEYDORN, K., et al., Neutron-Transmutation-Doped Silicon, Plenum Press w YorNe , k (1981) 193. [3] HANSEN, K., et al., Neutron-Transmutation-Doped Silicon, Plenum Press, New York (1984) 91. [4] ANDRESEN, K., et al., Semiconductor Processing, ASTM STP 850, 1984, 605.

324 INCREASING UTILIZATION OF RESEARCH REACTORS

BAG WANPING Reactor Irradiation Technology Application Laboratory, Institut f Atomio e c Energy, Beijing, China

Abstract

o highetw Ther e rar e power researche reactorth s i n IAEe i sOn . Heavy Water Research Reactor (HWRR). anothee Swimminth s i r g Pool Reactor (SPR). Two Reactors have been operating tor more than 20 years. They have made an important contribution in the areas ot neutron scattering experiments, irradiatio r radioisotopfo n e production, activation analysis, biological experiments, fued materiaan l l irradiatiod an n personnel training. Recent years, in order to provide valuable income and increase utilizatio t researco n h reactors e researcth , t reactoo h r irradiation technology application was emphasized.

Major progress has been made in the areas of neutron doping. Since e researc1979th , t neutroo h n transmutation dopin n semiconductoi g r material s beeha sn performed e year'Th . s D outpusilicoNT f o n 198ti n 4 was 3.2 tons. An output of 4 tons in 198b is expected.

We have started to engage in preparation of nuclepore membrane filters and its application. It is expected that the nuclepore membrane filters e areawil th e uset medicab ln o s i d l analysis; ultra-pure reagent preparatio d environmentaan n l protection analysis, etc.

1. INTRODUCTION

There are two higher power research reactors in IAE. One is Heavy Water Research Reactor (HWRR) e Swimming-Poo othee th th ,s i r l Reactor (SPR). These two reactors have been operating for more than 0 years2 . They have mad n importana e t contributio e areath f o sn i n neutron scattering experiments, irradiatio r radio-isotopfo n e pro- duction, activation analysis, biological experiments, fuel and material irradiation and personnel training. Recently, in order to provide valuable income and increase utilization, the research on reactor irradiation technology applicatio s beeha nn emphasized. At first e majoth , r progres s bee ha se are n th f mado a n i e neutron transmutation doping for silicon. Experiments on the irra- diation conditions, irradiation facilitie d annealinan s g after irradiation were carried out in 1980. The annual irradiation output of NTD silicon was 3.2 tons in 198^. Kour tons *ill be expected to produc n 1985i e n .199 I irradiatioe 0th n capacity 0 ton2 wil e sb l per year n 198 I .d 198 2an e silico th 3 n ingot d slicean s s were irra- diate r Wacker-Cheraitronifo d c compan n Wesi y t German d Komatsan y u Electronic Metals Co.Lt n Japani d e resultTh . s were satisfied.

325 In addition, recent years, the research on Neutron Radiography s engagewa t presentn SPRA i d. , some spare part f producto s s have been checke de resultoutTh . s were fairly good e installatioTh . f o n Cold Neutron Source is being built in HWRR. It can be expected that the installation will go into operation in 1986. We just began to study on preparation of nuclepore membrane filter and its application. Fission uroducts irradiation and etch technolog f solio y d nuclear track detector e combinear s o pret d- parate nuclepore membrane filters. The membrane has geometric capil- lary-shaned poresmootha d an s , flat surface e uniquTh . e characteris- tic f nucleoporo s e membranes make them idea r medicafo l l analysis, diagnosis, treatment; microbiology and bacteriology analysis; ultra- pure reagent preparation and environmental protection analysis, etc. In this report D silico NT e wor n th ,o k n n detaili wil e b l .

2. FACILITIES FOR IRRADIATION OF SILICON

In order to irradiate silicon, the irradiation facilities were built in SPR and HWRR. They occupy limited channels in the two reac- tors. Irradiation of NTD silicon is carried out with other irradi- ation experiments, So it makes the reactor income increase. 2.1 Swimming-Pool Reactor The cross section of the SPR is shown in Figure 1. The maximum thermal power of it is 3.5 MW. Nine tubes with inner diameter of

Reflector Irradiation (HI) Vertlca-i tub«- fV.I

| Fuel

f_J Beryllium box

Q$ Graphite box

• 10 . 1 . sf^tiof o n nrlnq-Poo, iw ) . Rcarto u p S ( r e adjacen ar e core th m l thesm Al .o t 0 t9 et we d tube an e m ar sm 5 10 with pool water. Irradiation facilities are shown in Figure 2. The characteristics of these eleven irradiation tubes are listed in Table 1. The silicon ingots are put into the irradiation basket. It rotâtes to ensure radial uniformity of irradiation fluence. To ensure the

326 ïï Holstln« head r~ a W . TYC-? motor -4* ooooooooo ^ ooooooooo Storage vel] Basket

N * Sel f-powercr) detoctor ' 31 Irvcot 1 J 1e 1-f

Fig . 2 .Schemati P5 R o irradiatioh t rfcjrji l i cf s o mit d an n y fact i 1 i ;; toraq L1 . e w e

Fable 1. Characteristics ot the S PI- Irradiation r'.ici li ti e&

Facility Name V.l. . K .[

Loca tion Water pool Reflector Number of tubes available 2 9 Thermal flux $^ ( n/cm^ • s ) .' ' - 3. i ) * ' 0 l -

Ratio <|>th/f ( (fif-fast flux E> 1 MeV 10-20 Irradiation environment Irradiation temperature of Si i mjot (°C ) 4 U 40 Maximum diamete i inyoS f o tr (mm) 9b 55 Maximum length of Si ingot (mm) 1 50 150

axial uniformity, once the irradiation fluence reaches one-half of the total predetermined dose, the silicon ingots are turned upside down or exchanged in position with respect to each other by means of a manipulator located at one side of the reactor hall QR shown e storagn Figuri Th . 3 e wel s r i temporarusel Co d y storage th f o e irradiation basket.

327 Fig. 3. Manipulator for exchanging position ot ingots.

2.2 Heavy-Water Research Reactor The cross sectioe HWRth Rf o ncor s i showe n Figuri n e . The maximum thermal power of HWRR is 1 5 MW.

— - -^———- Graphite reflector

- Fuel channel

-——— Controd ro l

_ __ Vertical expérimental channel

\ " Heavy vater reflector

_ Poaltlo_ _ f horizonta_ o n l channel

Fly . 1 Cros. s sectior Ik'.th if vy-Wo n r Researcate h Reactor (IfWRR).

e maiTh n parameter D silicoNT f o s n irradiation facilitiee ar s listed in Table 2. The schematic diagram of the irradiation facili- tie s showi s n Figuri n . 5 e

328 2 . Cha r ic t eristics öl th( Iit-i<1i>tion Fc

1 or i l i t v 'l imc <-inch 4 in

L/ocitio< se ( n #31 Vortical er 11c a ) l a r l l r Channel Lhannel channel Thermal flux $ (n/cm2-s) t4-9) x I0n (4-9) > 1013 (4-9) > 1013 Ratio $ , /if, ( (fy-f ast flux 0 >5 0 >5 0 >5 E>1 MeV) Irradiation environment air air i l r Maximum irradiation tempera- ture (°C) 0 18 ' <15 0 018 Maximum diameter of Si ingot (mm) 52 82 1 DO Maximum length of Si inqot (mm) 280 ^50 200

Hrtntlon aonltor

Hotatlu« tube Compieased air passage Detector pip« Compressed air Vertical channel

Self-powered detector "Can No.2 n No.Ca 1 Detector pipe

; end shield in/ç

F'9 ?i>a 11 c diagrjTTi of i r r id i a 11 01 facilities in the

Two Irradiation facilities for N'l'D of larpc .silicon ingots have al- ready been installe e verticath n i d l channels 9 ari2 O 2/+N dO N ,, which are in the outer heavy water reflector. A four-inch facility in channe 1 wil 3 e installe b lO N le nea th r n i futured . All these irradiation facilitie e isolatear s d from heavy water. Irradiatio t inte nfacilitypu th ocan e ar s n ordeI . o ensurt r e th e irradiation temperatur silicoe th f o en ingots less than 180°C.a lead shielding wit e s sidplacea i thickneshth em c t a adjad1 f so - cent to the core to reduce the gamma heating in silicon ingots. A forced circulating system of compressed air is used for cooling

329 silicon ingots e radiaTh . l uniformits ensurei D y meanNT b d f o ys of rotating the tube containing the irradiation cans. It takes the same way as SPR to ensure the axial uniformity. A remote ajid automatic handling device is used for handling cans of NTD silicon during the reactor operation. e irradiatioTh n fluenc e activatio s giveth i e y b n f Cobalto n - Aluminum alloy foil attache o eact d h can t .calibrateI e selfth s - power detectors which are placed at the side of the irradiation tube for real-time control of the irradiation fluence of each can.

. SITUATIO3 N ABOUT IRRADIATIO D SILICOE NT NIA N I N

At present e varietieth , f irradiatioo s e ar D silicoE NT nIA n i n shown in table 3.

Table }. Varietiec of irradiation NTD silicon in

Varieties NTD silicon NTD silico D silicoNT n n NTD silicon for power for radiatio r integrafo n t for stand- devices detectors ed circuits ard slices range of resistivi ties 10k-19k 20 , 180 ( fl-cm) resistivity tolerance £10* ±10%. radial resistivity 3$ nonuni formity axial resistivi ty i formitun n no y minority carrier life- 100 10000 30 ) c se timu , ( e

application high power radiation integrated national fields rectif, es l detectors circuits raetrological thyrietors, standard power diodes, transistors

330 D silico3.NT 1 r powefo n r devices e skilTh n thii l s fiel f N'I'o d D silico r powefo n r device s rathei s r ripe t presentA . D ,silico NT mos f o t n products supplie E belonIA y b gd to this kind. It is widely supplied to the domestic material and device factories. Becaus D dilicoNT e s pricisioha n n target resistivi- tied dopanan s t homogeneity e propertieth , f poweo s r devices made s fairli fro t i my uniform e quantifieTh . d product rate e prettar s y hight. 3.2 NTD silicon for radiation detectors It is very difficult to fabricate a high pure and high resisti- vity N-type extrinsic silicon, whic s resistivitha h y more tha 0 kJîcm1 n , dopant homogeneity and higher minority carrier lifetime, with con- ventional floating zone method. In order to meet the domestic needs r atomifo c energy industr d nucleaan y r science e startew , o engt d - n thii e s ag D projecsilicoNT e r radiation 1981th i fo tn d an - , de n tectors were produced in 198/4. During this period, we solved three problems : (1) It is widely recognized internationaly that mono-silane SiHr is suitable as the source gas for producing the raw material of the high purity silicon. But we adopted SiHCl-z in stead, which is ob- tained easil t homea ye coss reducedTh .wa t . e neutroTh ) n(2 doping rule n closi s o stict e k compensating region were mastered. We can control irradiation parameters accurately and advance reasonable requistion for starting material. presene th ) f Makino (3 t e diffusious g n furnace, irradiation silicon ingots were annealed. It's techniqu s improvedwa e D silicon'NT . s minority carrier lifetime was raised form 1500 /usée to 2500 ;usec. This has enabled us to fabricate some PIN current-type detectors with a large depletion depth, which can be used for fluence determi- nation in reactor core and high precision nuclear datas determi- nation satisfactory. The qulitified product rates of the radiation detectors were raised from about 1$ to 7%. D silicoNT r integrate3 fo n3. d circuits w resistivitlo e s obtainedTh wa D dilicoC 1 NT y r y makinb ,fo n g usf Czochralsho e i silico s startina n g material s richa ht I .oxygen , n intrinsia whic s ha h c gettering effect. Combining this effect with pricision target resistivit d dopanan y t homogeneit D siliconNT f o y , the good performance silicon ingots wer t thesePu produce. e 1C r fo d material on probation for middle and small scale MUS 1C. The results were fairly good. 3./4 NTD silicon for standard slices This products are used as national metrological standard. Some

331 affecting fluence factors were researched systeraaticaly. The integral fluence toleranc e controlleb n ca e d within -~5%» e standarTh d slices have a good stability. After storing one year, the stablity deter- mination showe s thae u recistivitLed th t e standarth f o s d slices didn't change.

. k FUTHER EXPLORATION

Research NTw way r w Dne usin fo ne n smaterial o se g th irra d an s- diation techniqu e underwayar e . ^4.1 Preliminary study on the doping of GaAs by neutron transmutation Wite similath h r principl f NTo e Df semiconduc silicono t lo a , - tor materials can be dopant through nuclear reactions. GaAs is a very useful material. Undoped GaAs crystals have been irradiated with thermal neutron o introduct s e shallow donors e irradiationTh . - induced damages can be removed effectively by thermal annealing. In this process, the expected doping level ( <^5X10 ' cm"*) can be ob- x tained with the integral neutron flux 3 10^"cm~2€ After annealing at

600°C in H2 ambient for 2.5 hours, the homogeneity of the doping of the wafers is determined by the electrochemical C-V technique. The results show that the relative standard deviation of the doping concentration is less than 5#. J+.2 Preliminary study on semi-conductor devices Gamma radiation minorite th f I y carrier lifetim n semi-conductoi e r devics i e longe device turth f timth s of i f ,nlong o ee , which affectn o s using frequency of device. The conventional method (diffusion gold) s difficuli o controt t l minority carrier lifetime qualitifiee Th . d product rat s i elow . Gamma radiatio n makca ne crystal suffen a r amount of damage to reduce device's turn off time. The value can be controled by varying irradiation doee. It is not only accurate but convoient. The thyristors have been irradiated by Gamma radiation which is produced after the reactor is shut down. We obtained obvious result. We are going to build a waste fuel elements storing pool and use it as Gamma source. We are trying to make contineuous efforts to increase the applications of these two reactors. In addition to meet the domestic needs, we would like to provide an irradiation service for abroad and cooperate some projects with other countries.

332 OPERATIO UTILIZATIOD NAN F NO THE SWISS RESEARCH REACTOR SAPHIR

H WINKLER Swiss Federal Institute for Reactor Research

W BUHRER Labo r Neutronenstreuunfu r g Wurenlmgen, Switzerland

Abstract

The Reactor SAPHIR is a swimming-pool-reactor with MTR type fuel elements t becamI . e critica Aprin i l l 195 Wuerenlinget 7a d an n operate powea t f a 1MWdo r . After several modifications and improvements during the years the power has been successively increased. SAPHIR has operated since January 198a therma t 4a l powe f 10MWo r . Todays operation schedule is 3 weeks full power followed by one week low power operation. So a total of about 330 days of operation per year is achieved. At full power operation the reactor will mainly be used for: - Beam hole experiments: Axi3 d sfou an Spectrometer 2 r operation i e sar n mainlr fo y solid state physics - Isotope production for medical and industrial applications - Material Testing, especially examination of pressure vessel steel - Activation analysis - Silicon dopin d othean g r irradiation services - Irradiatio nw enricheTestlo f R fueo s MT dl elements (RERTR-Program) w powelo re Ith operation n phas e reactoth e uses i r d for: - Training and education of power station operating persona d studentan l s - Experiments in connection with improvements of the reactor and safety systems. The following presentation will treat mainly the operational aspects, improvements made for experimental equipment and some applications.

. Introductio1 n The Reactor SAPHIR is a thermal, light water moderated and cooled, open pool type Research Reactor with 23 Plate MTR-fuel elements, operate Swise th sy b dFedera l Institut r Reactofo e r (SFIR) Research t Wuerenlingea n (Switzerland).

333 s originallIwa t k yRidg Oa designe e e th Nationa y b d l Laborators a y an Exhibition Reactor for the first "Atoms for Peace" Conference in 1955 under the name "Project Aquarium". After that conferenc Reactoe th e s purchase wa rSwise th sy b d Government on behalf of the SFIR (former RAG) and rebuilt by Institute people as a 1MW Research Reactor in Wuerenlingen. It first went critical at the new site in April 1957 and was named SAPHIR. Since December 195 7operatet i r morfo de than

10 years at a max. power of lMWfch for a broad palette of experi- ments suc: Isotopas h e production, Material Testin d irradiaan g - tions, fuel irradiations, Loop d beaan -m hole Experiments etc. During this time Research work on Reactor Kinetics and dynamics was also done. From this work today's routine reactivity measuring programs such as:Rod-drop-, Inverse reactor kinetics- (INKIN) programs r coarsefo d fin-an e contro d calibrationro l , bur p determinau n - tiod generaan n l reactivity measurements have been developed. The power level was raised, after a total renewal of the

instrumentation, to 5MW in 1970 and to 10MWth its present operational level in 1984. A further power increase to about 15MW seems feasibl e neath r n i efuture .

2. Reactor Description SAPHI s lighi R t water moderated open pool reactor which operates a therma t a l powe f 10MWo r e thermaTh . l neutron flus i x -108 13 n'cm e corth e t a surface1 o 1,2-1t p u , 0 "* e ith n central irradiation positions and I-IO1"** at the beam hole nose behind a Beryllium Reflector. e ReactoTh r building contain e Reactorth s d Experimentaan - l Hall, Control Room and all rooms for the necessary auxiliary equipment suc s wora h k shops, water purification, electricity distribution and offices. A cross section view of the Reactor building is given in Fig. 1 and 2. The core is assembled from standard 23 fuel plate MTR fuel elements. At presen o typet tw therf elemen so e ar e usen i t ; a hig h enriched (93%) with 280g a mediuU-23 d an 5m enriched (45%) with 320g U-235 e standarth r fo d element.

Ground t*»t«t

334 « Ld n I I »M r o

A standard core configuratio element2 3 n o consistt d 0 an s3 f o s 15 Beryllium Reflector Elements (2Varrangement8 x 2 7 sidea n i ) . e meaTh nf suco bur a corp h u ns abou i e% (maximu30 t m burn-up 65%) at beginnin f cycleo g o incorTw . e irradiation positions servr fo e Isotope production and other high flux irradiations. Four fork type control rods (Ag-In-Cd) serve s shid a ssafet an m y a stainlesd centra rodd ol an se th l sf typo stee s regulatind a e ro l g rod. e pooTh l (Fig s 2.9i .) m3 wide m lond 9 8.4, an g m dee d containan p s about 210m3 demineralized water. The reactor bridge is movable alon e pool th ge reacto .Th n operat positioy ca r an o t t a ep u n

Q

335 lOOkW but only in the zero-position at full power. This feature has mainly been used in the past for shielding experiments and mainte- beae nancth m n holeo e . Five radial- and one tangential beam hole, all equiped with special developed shutter-plugs serve mainl r neutrofo y n scattering experi- ments e arrangemenTh . beae th m f tporto s givei s Fign i n. 4 . Operatio e reactoth d staff no an r f levels e reactoTh operates i r thren i d e wee4 shift a k t cyclea s , 3 week continuously at full power followed by one week for mainte- powew lo nanc rd an operatione totaa o f abou.S o l day0 t27 f fulso l power and 60 days of low power operation is achieved per year. The operating staff consists of 17 to 20 persons (6 operators and shift supervisor Senio7 o t sr5 eacReactod an h r Engineers) including the reactor management. An operation group includes one operator ; e shifon t superviso Senioa d an rr Reactor Enginee n stand-byo r . Research and utilisation The SAPHIR supports research in many areas. The facilities are described briea belo d fan w mentioe researcth f o n h program wile b l given. Neutron scattering The main research activity is neutron scattering. Four Spectrometers l equipe e placeal ar , 5 n portdo do t wit 2 s h inpile filters (Silicon single crystals, coole o liquit d d Nitrogen temperature):

Fig show1 ' . a shorizonta l section through th< -e centecoreth f ;o r thef e fivar f e radial ari';r>ntiabeat e m on tube d l an sbea m tube.

Nr. 2 and 5 are triple-axis-spectroraeters with vertically and horizontally focussing monochroraators and horizontally focussing analyzer crystals. The curvatures are variable and allow an adaption of the spectrometer resolution with respect to the physical problem to be studied.

336 Ne.3 is a powder diffractometer with an LCC 400 (Thomson-CSF) multidetector coverin angulan a g r° witrang80 resolutioa hf eo n of 0,2°. All spectrometer completele ar s y automated (LSI-11/23, CAMAC) with a high flexibilit botn i y h experimental condition datd san a analysis. The source and the spectrometers are adequate for studies in the thermal neutron region. The scientific program includes structural and dynamical aspect magnetif so c specimens, hydrogen storagn i e material biologicad san l systems, lattice dynamic phasd san e tran- sitions activn bases a i n t do I .e collaboration between staff members and scientists from universitie ohted an s r laboratories. Improvement SAPHIe th o Rt s facilitie r neutrofo s n scattering have been made step by step along the path of the neutrons: - upgrading of the reactor power to 10MW (1983/84) - new beam tubes and plugs with a larger beam Cross-section and He- fillin o reduct g r scatterinai e g cooled silicon single-crystal filter o improvt s qualite e thermath eth f o yl beam (1984).

- Larger monochromator crystals with variable curvatur dimen2 n i e - sions (Graphite 1985; Beryllium 1986/87). e radioisotopTh e group usee higth s h neutro ncentrae th flu n i xl irradiation positio produco t n e radioisotope r medicafo s d induan l - strial applications. In addition irradiatio differenr fo n t purpose d researcsan h activi- ties are executed. More than 1000 samples have been irradiated last year. Semiconductor Silico P-dopinr groune fo n th f dgo materia s irradiatei l d routinel manufacturr fo y higf eo h current switches. About 200kf go silicon rods of 20 to 100mm diameter will be handled per year but the full possible capacit t useno ds i yyet . Neutron activation sample e irradiatesar pneumatia n i d c rabbit system. The NAA is used for trace element identification in different materials s fooda , impuritie watern i s , environmental researcwaste th ed han disposal program. Material testing In connection with the material testing and safety program of the Institute, pressure vessel stee s irradiatei l d under operational conditions e mai.Th n purpos f thieo s progra o determint s i m e th e operational lif f pressuro e eSwise vesseth sr fo nucleal r power stations. Trainin d educatioan g nuclean i n r technology Training program offeree operatine sar th o t d g peopl Swisf o e s nuclear power stations and research reactors. pars A f thesto e courses SAPHI s use i Rperforo t d m practical experi- ment reacton i s r physics. Also regularly basic experimental courses on reactor operation and physics are performed at SAPHIR for Students of Universities and Technical High School connection i s n with their training program. These courses will mainly be given in the low power operation phase.

337 RERTR-Program A great effor bees e IAE ha tth pase n A th n madreduceto n i e d enrich- ment program. For demonstration purposes medium enriched fuel has been introduce e core th e progra .Th n i d m forsee operation sa n with a complete MEU-Core which is riched end of 1985. In orde o test e new'r th t s develope w enrichelo d d silicide fuels, twenty complete fuel elements have been ordered at two fuel manu- facturers. This high density uranium silicide fuel element contains 410g U-235. They will be put in the reactor at the beginning of d irradiate morf an 198o bura 6 p eo u nt tha p u dn 70%.

Future prospects During the past, continuous work was done in order to hold the reactor SAPHIR at the state of the art. So different developments to improve the experimental possibilités of the facility, to replace old, inadequite equipments and to improve reliability, earned out. e futurth r e Fo further improvement plannee ar s : as d A further increase of the power to about 15MW is envisaged in near future, the study for implanting of a cold source in the reactor has begun, tests were made for a neutron radiography equipment a fas d t an Gas-jet-Syste undes i m r construction.

338 APPLIED RESEARC SERVICD HAN E ACTIVITIES UNIVERSITE TH T A MISSOURF YO I RESEARCH REACTOR FACILITY (MURR)

D.M. ALGER University of Missouri, Columbia, Missouri, United State f Americo s a

Abstract The University of Missouri operates MURR to provide an intense source ot neutron and gamma radiation for research and applications by experimenters tros touit mr campuse y experimenterb d an s s from other universities, government and industry. The 10 MW reactor, which has been operatin n e averagpasa b hourgth Ib r t wee r pe t seigho to ek t years, produces thermal neutron fluxes up to 6-7 x 10^ n/cm -s in the central tlux trap and beamport source fluxes ot up to 1.2 x lü14 n/cm2- s.

e missioe reactoTh th t o n r facility o promott , e research, education d e serviceoveral an th e sam th s a es li , missioe universitth f o n d an y therefore, applied researc d servican h e supporte y industriab d l firms have been welcomed. The university recognized after a tew years of reactor operation that in order to build utilization, it would be necessary to develop in-house research programs including people, equipmen d activitan t o thas y t potential users could more easild an y quickly obtain the results needed.

Nine research areas have been develope o creatt d a broadle y based program to support the level ot activity needed to justify the cost ot operating the facility.

Applied researc d servican h e generate financial suppor r aboufo t t one-halt of the annual budget. The applied and service programs provide strong motivatio r university/industrfo n y associatio n additioi ne th o t n income generated.

Perspectiv n Researco e h Reactor e Uniteth n i sd States Applied research and service activities at research reactors involve pri- maril e businesth y f producino s d effectivelan g y using neutronse th n I . United States last year, the total applications of neutrons comprised a very "large business e firsTh . t slide i11ustr atee ordeth sf magnitudo r f dollaro e s spent in each of several technical areas. Because of the difficulty in de- fimng what activities shoul e includeb d n eac i e dproble hth ared f colan o ma - lecting complete, accurate information, the actual dollar amounts in each area M only be considered as approximate values. Clea'-ly, the greatest commerce that uses neutrons in the U.S. is the power producing industries, followed in second place by nuclear defense. The remaining five categories summarize the use of U.S. research reactors and out- e 1-nutilizatioth e e nsubjec th tha s i f tthio t s seminar e UniversitTh . f o y Missouri Research Reactor (MURR) contributes to each of these areas.

339 Radioisotope productio n researci n h reactors stimulate e nexth s t largest

dollar volume e eyebusiness th f somo sn i e d peoplean , , particularly those geneallr y opposed to anything called nuclear, it provides the strongest and sometimes only justificatio r operatiofo n f researco n h reactors. Neutron pro- cessing alter e materiath s l being treated d involvean , s such activities a s neutron transmutation doping of silicon, radiation damage studies, coloring of gem stones and production of membrane filters. The utilization of research reactors for processing has increased markedly the last ten years because of the development of technology for using transmutation doped silicon. Several papers wil e presenteb l d this wee n thio k s subject alone. Neutron scattering studie e spas th hav tn i ebee n primarily basi- re c search. But more recently, applied research and service utilization have been increasing. Several examples will be presented later in this paper. Neutron interrogation covers those non-destructive applications such as neutron radiography, gauging, calibrations, etc. not included in one of the other areas. There have been about 260 non-power reactors built in the United States since Enric oa tea Ferm f d scientisto m an i s buil e firsth t t reactor undee th r athletic stadiue Universitth t a m f Chicago y n Decembeo o , 19422 r . Abou7 13 t of these reactors have been shut down, leaving 124 still operational. This next slide show e poweth s r level distributio f theso n e operating facilities. The power levels range from less tha 1 watn o 4,000,000,00t t 0 watts. A large number of these reactors were built and are still operated to serv a singlee , dedicated functio d thereforan n e fundinth e s assurei g s a d long as the original objectives are required. These facilities would likely e shub e tpresen th dow f i n t purpose shoul d ratheen d r tha e converteb n o t d general utilization facilities. As examples, all of the facilities operated above e 1,00user materiaar fo dW M 0 W lM production0 10 o t 0 1 ;e seveth f o n reactors are used for training naval reactor operators and testing reactor

materials, components and opérâtng concepts. Two of the 10 to 100 MW re- actors (Loss-of Fluid Test Facilit1 y and Power Burst Facility) are used to test power reactor syste d fuean ml performance during accidents. There are about 40 general purpose reactors like MURR owned and operated by the federal government, industries, or universities that are involved in varying degrees in providing applied research and service to cover partially or totally the operating costs. The MURR Facility The M'JRR, located in the Research Park one mile south of the Columbia campus (next slide), is the highest powered, highest neutron flux facility not operated and owned by the federal government (next slide). The 10 MW reactor,

which has been operating an average of 155 hours per week for the past eight years (next slide), produces therma l~ 10 neutron/c x s m~ 7 n6- fluxeo t p u s e centraith n l flux trap d beamporan , ~ 10 tx sourc2 1. o et fluxep u f o s n/cm ~s. Since the reactor is already operating at the maximum hours per week, the reactor staff is now involved in safety analysis and redesign to in- crease the power to 25 to 30 MW and to add a cold source and guide hall to en- hanc e neutroth e n scattering capability. e nexTh t slide show n isometria s e creactor th vie f o w , whic s locatei h d e botto a ininth n f eo m meter deep poo f ligho l t water e experimentaTh . - fa l cilities can be seen to consist of six beamports, the flux trap central hole and the reflector region, which contains irradiation holes for underwater handling as well as pneumatic tube transfers. These facilities are also shown e nexith n t slide, whica pictur s i h e taken from abov e opeth e n pool.

340 e MURTh R Program

The University of Missouri operates MURR to provide an intense source of neutro d gamman n a radiatio r researcfo n d applicationan h y experimenterb s s from the University's four campuses and by experimenters from other universi- ties, governmen industryd an t .

The missioe reactoth f o n r facilit o promott y e research, educatiod an n service is the same as the overall mission of the University, and therefore applied researc d servican h e supporte y industriab d l firms have been welcome. The university recognized after a few years of reactor operation that in order to build utilization it would be necessary to develop in-house research programs including people, equipment and activity so that potential users could obtain more easil d quicklan y e resultth y s needed. Verpeoplw fe ye ar e willing to change technical fields or to become sufficiently competent in the use of neutrons that they can function alone.

Nine research areas have been developed to create a broadly based program to support the level of activity needed to justify the £ost of operating the

facilityi \,j .* Thesi ' i j w, uradiatio u ^ c i ' ' - ' y ef »n IUUIU^IVM c i — fects , nuclea nuclear rengineering engineering, ,neutro neutron nactivatio activation nanalysis analysis, ,radioisotop radioisotope eapplica applica- - tionsti ons, instrumeninstrument developmentdevelopment, neutroneutron radiographyradiography, reactoreactor chemistrchemistry anand nuc-- 1 ear science. Some of these areas are much more active than others. Applied research and service generates financial support approaching pne- e annuath hal f o lf budget e applieTh . d researc d servican h e programs provide strong motivation for urnversity/indjstry association in addition to the in- come generated. These associations suppor e missioe reactoth tth : f o by nr ) providin(1 g facult d studentan y s with real world problem o solvt sd witan e h the excitement that comes from seeing their efforts being utilized; (?) bringing new ideas to the facility, keeping the research current and compet- itive, and providing some *ocus to the education of students; (3) providing contact betwee r studentou n d industriean s s that wan o hirt t e them d givinan , g students confidence about their future success on the job; and (4) meeting the needs of industry both within and outside the state of Missouri. Some Specific Applied Researc d Servican h e Projects A program that fits inte neutroth o n radiography area becaus t sharei e s tne Jtilizatio e thermth * o n! colum d usee trac<-etcan nth s h technologs i y tne processing of thin plastic fil"', that is jsed as a filtering material. The first slide illustrates the processing technique, which involves first passing e approximateltn x microsi y n thick film pas a uraniut m foil tha s undergoini t g fissioning from bombardmen y thermab t l neutrons e fil Th s thei .m n passed tnrojg a bath o etct h h holes completely throug e filth h m alon e damagth g e trac

341 In ojr neutron scattering program, joint university/industry research has been growing at a rapid rate. One example of successful cooperation is the application of a new position sensitive detector in the neutron diffraction analysis of magnetic materials. The next slide shows a schematic diagram of the relatively inexpensiv ( e$100,000 ) detector which reduce e backgrounth d d noise, increase e resolutioth d d increasean n e signath d l count a rat y b e facto f o fiftyr . General Motors Corporation funde a projecd o analyzt t a e "ewly developed hard magnet material e powdeTh . r diffraction date showar a n e nexth t n i slide alon ge data witth e Rietvel th o .h t Thi t fi ds stud- re y sulted in the first determination of the crystal structure, NdjFe^B, shown in e nexth t slide. Many other companies (Exxon, McDonnell Douglas, Monsanto, etc.) are now supporting applied research on a wide variety of materials using neutron scattering.

Sorre recent exci tenent has been generated in our gamna-ray scattering program by the analysis of the first space grown Hgl? crystals. An applied research program wit e companth h y EG& s i Gcentere a gamma-ra n o d y scattering instrument at MURR that can analyze the crystal perfection of high atomic number materials. A view of the detector end of the instrument is shown in the next slide, with a closer view of the mounted crystal shown next. The next slide shows a picture of a Hglj crystal grown on the earth and the next e crystath iictur f o l s i egrow n under gravity-free condition e Space'ath n o s b 3 -Mssion. The space grown crystal looxs better because of the flatter facets a quantitativ t bu , e nexo slidesth e seeetw b tn ' vien ca w, which show the rocking angle curves for the two crystals.

MJRR will provide portable gamma-ray diffraction instrument r aboufo s t $20,000 and $10,000 pe r year for sources to anyone interested. There is a neer thesfo d e instrument e electronith n i s c crystal growth - industrma r fo y terials such as CdTe, GaAs, GaP and InP.

I would like to describe two projects in our neutron activation analysis program that fit the subject of this seminar and which may be of interest to others e firsTh t. involves trace element analysis relate o humat d n health, with selenium bein f particulao g r importance nexe Th t . slide illustratee th s relationship betwee various mineral d theian s r health effects d identifiean , s 0 those detectabl y NAAb e . Notic e eknow th tha f no t essential elementsn ca % 93 , be adequafely measured by NAA, and for five o*" ther, includ ng Se, NAA is the metho f o choiced e nexTh t . slide show e importancth s f o seleniue n mi huma n corona-y heart disease (CHD) and cancer.

It was the development of a rapid, inexpensive technique for analysis of Se that generated a progra^ that now evolves more than fifteen researchers at six medica" centers who provide more than 6,000 samp]es per year. A compari- o e mpanalysiS tw fhod sof r o o e f ns nex i showth s n t o nslide e measureTh . - ment of the short half-life Se-77m enables us to prpcess about 400 samples per da> with a very quick turnaround time. Using mpthod I, we had to wait for about six we^KS to determine the results.

The second project (next e analysislideth s i f ) impuritieo s n i semis - conductor silicon. This program, which is a spin-off of the neutron transmu- tation doping activity, involves about seven companies that routinely senn i d samples and about eleven other companies. The advantage with NAA is the large nu-ibe f elemento r s measured simultaneousl e adequatth d an y e sensitivitr fo y many elements of interest. To us, this NAA is primarily a service activity, while to the companies it is applied research.

The last example that I will present comes from our Radiation Effects program area wher e eactivit th mos f o t s i centerey n understandino d g radiation damage in semiconductor materials. In this case, however, we are involved in assisting several group n i colorins stonesm e nexge g Th t . slide shows some

342 natural, nearly clear stones as well as some stones that have been treated in the reacto o enhanct r e their colo d consequentlan r y their value. The next slide summarizes the level of involvement of MURR in providing service to other educational institutions, industries and laboratories. As discussed earlier, this involvement benefits the facility in many ways and has a value whic r exceedfa h e monetarth s y incoTie. In closing I woul, d lik o exprest e y opiniom s n thae potentiath t l benefit of this seminar is not in creating competition between reactor facilities but in providing example f succeso s o thost s e contemplating industrial associ- ations, in stimulating ideas that will generate new uses of our reactors, and in providing informatio o ownert n d operatoran s o thas s t then mak- ca yex e isting reactor service technologies availabl w industriesne o t e .

APPLICATION NEUTRONf So S U. e th n Si

YEARLY RATE Do'lars (Millions) 1 10 100 1000 1000C

Nuclear Delense

Radioisotopes Productioe Us n&

Neutron Processing

Neutron Scattering

Neutron Interrogation

Trace Element Detection Slide 1

TOTAL NUMBER4 12 . 100- <10.000 0 MwLZ4 I

103 0- OOO U OMw

1 - 0<10: 0MW

1 <10MW

W M 1 < 1 0

1 0- <10 W 0K

W K 0 <1 - 1

<1 KW I 34

0 5 10 15 20 25 30 35 40

NUMBE F REACTORHO S

POWrn LfcVEL DISTRIBUTION Or Slide 2 UNITED STATE N POWENO S R NUCLEAR REACTORS

343 OPERATING EXPERIENCE UNIVERSIT f MISSOURYo I RESEARCH REACTOR

60 OOO 10MW 155 Hrs/wk 990 55 000 I' h ' n 50 000 1 \ i eoa

1 45000 Œ 0 -170 u. 1 1 , i- 0 40000 10MW - 100 Hrs/wk 5 5 n J ; 600 S 3 35 000- V 1 >. -|L ,{ - 500 § g 30 000- i N , j.x< 3 Ul | ^ 5 25 000 - o D 40 , cr 1 <••% K 20000 5MW 100 Hr 3/ wk ' -303 g 0 15 009 n 11 1 \ f 1 I 1 j ^ 10 020 i 1 1 y \[^ 1 [ 1 1 1 L 1 | J 102 H DO ^wtir j 5 000>- -" .j rfittiL J Jj i L . _ Jo t1 T U tf 1967 197 0 1975 I960 1985 1990 Slide 3 CALENDAR YEAR

COCK *«C WATE« G1APH TE AND P KA T * U T

BASE &L,*PO«TEC COcÜWT B ) N O* BED«OCH

Slid e4 UNIVERSIT MISSOURF YO I RESEARCH REACTOR

344 25mm B.C

OSCILLATING ' RADIAL COLLIMATOR

6 10mm SAMPLE

tOOmm MASONITE

50mm MASONIIE

PREAMPLIFIER I BOX

p" 305m n- Slide 5 POSITION SENSITIVE DETECTOR

12000

-4000 WOO -TOGO

_l—————1—————L_ 0 6 0 5 0 4 O J 0 2 > K 0 70 80 90 20 (deg)

Slide 6 POWDl H DirrRACTION DATA (or NdFe,B ; 4

e F l a e ar roi 6 ed an Layer 5 23 s

Slide? CRYSTAL STRUCTUR f Nd,FeEo MB

345 Hgl2 SEED PORTION (terrestrial growth)

Gamma Diffraction FWHM A 0.18°

o cc o 10 o 30 o 10 D un o se oc: a ~>n ai:

Slide 8 ROCKING RKGLE IDEGREESI

GROWTHglW NE 2 ZERHn i O GRAVITY

0 -i0 O0 Gamma Diffraction FWH M= 0.08 °

0 30 C SO 0 UO û 50 0 60 0 10 0 10 D 00 1 00

Slide 9 HOCKING ONGLE (DEGREES)

346 Minerals, Trace-Element Humad san n Health

known suspected non-essential essential essential toxic elements elements elements

Ça* CI* Co** As** Ag**

* Fe Cr** Cu * F Be

* Mg * K 1* Ni * Cd*

Mn** Mo** Na * Si Hg*

P Se** Zn* Sn* Pb

V** Sb**

14/15 (93%) 6 (67%4/ ) 6 (67%4/ ) 22/27 (81%)

»determine A wilhNA adequata dvi e sensitivit r biologica'o y l samples Slide 10 **NA methoe th s A i f choic o d e

Importanc f Seleniueo mHuman i n Health Coronary Heart Disease (CHD Canced )an r

Se status obs. health effect case-control studies

acute deficiency (KeshansfataD CH l ) China chronic deficiency increased CHD risk US. Finland chronic deficiency increased cancer risk US, Finland

Slide 1 1

Compariso f Seleniuno m DeterminationA NA a svi

parameter method 1 method 2

target Sc-74 Se-75 abundance 0.87% 9.0% cross section 52b 21b product Se-75 Se-77m decay EC IT halflife 118.5d 17.4s prin. gamma 265 keV 162 keV thermal (lux 1E13 1E14 fluence 1E19 5E14 detection GRS GRS IT/DT/CT 50h/30d/1h 5s/15s/25s -9 sensitivity 1 x 1Cf 10 grams 0 1 gramx 1 s sub ppb ppb analysis rate 25/da hrs4 (2 y ) 400/da hrs8 ( y ) sample cond. destructive non-destructive Slid2 e1

347 Neutron Activation Analysi Measuro t s e Impurities

in Semiconductor Silicon

Numbe f Companieo r s Served

6-8 Regular customers Infrequen2 1 1 0- t customers

Equipment-

Three dedicated germanium detectors coupled to a ND6700 Analyzer System offe totaa r l capacit2 sample-1 9 r dayf o yspe .

Element0 4 s Routinely Sought

u C i N o C e F r C i T c S a C K a N g A o M r Z r S b R r B e S s A a G n Z Cd In Sn Sb La Ce Eu Tb Yb U Slidh T 3 e1 g H u A t P r I W a T f H u L

SERVICE

50 oer viue i u \J UItî ClI ir IS I INCOME r - 2 0 a Grants r E3 Service

5 1 30 i

20 - w 1 0 i

V) CO , 3 D 0 5 10- i c c o 0 - c OT c 13 M I Mo Mo H Mo y 5 8 4 8 3 8 2 8 1 8 0 8 9 7 8 7 7 77 6 5 8 4 8 3 8 2 8 1 8 0 8 9 7 8 7 7 77 6 YEAR YEAR

70 Servico et Ir dustry

--, 60 Service to State and 50 - ——] Federal Agencies

40 30 - ~ I 30 i 20 - I 20 I ini 10 10 t , ' i I J Mo' Mo Mo, Mo -jL Mo Mo Mo i 76 77 78 79 80 81 82 83 84 85 5 8 4 8 3 8 2 8 1 8 0 8 9 7 8 77 7 YEAR YEAR Slide 14

348 UTILIZATION OF RESEARCH REACTORS AT TROMBAY

S.M. SUNDARAM Bhabha Atomic Research Centre, Trombay, Bombay, India

Abstract

e threTh e thermal research reactor Trombayt a s , Apsara (400 kW), Cirus (40 MW) and Zerlina (100 W) have played a vital role in furthering the programm t nucleao e r researc d developmenan h n Indiai t . Dhruvaa , 100 MW thermal research reactor, has been built and is presently under commissioning.

e reactorTh s have been extensively utilize t onlr basino dfo y c researc e fieldth n t nucleai o hs r physics, solid state physics, chemistry and biology, but also tor the development ot techniques in neutron activation analysis, neutron radiography, etc. Operatio f theso n e reactors have also enabled productio t largo n e quantitie f radio s o isotopes tor industrial and medical applications to meet our growing needs. The research reactors have been effectively used as a training tool tor manpower development in various disciplines tor our nuclear power programme.

With the commissioning ot Dhruva, enhanced production of a variety of radioisotopes used in medical diagnosis and therapy will also be met.

. 1 APSARA, CIRU D ZERLINAAN S At Bhabha Atomic Research Centre (BARC), Trombay, the three research reactors, Apsara (400 kW), Cirus (4O MW) and Zerlina (100 watts) have been in operation for over two decades and have played a vital role in furthering programmes of nuclear research and nuclear power development in India. Apsara, a pool type reactor commissiones ,wa 1956n i d . Cirus a natura, l uranium fuelled, heavy water moderated and light water cooled, research reacto commissiones rwa n 1960i d . Zerlina, a natural uranium fuelled heavy water mode- rated zero energy research reactor, buil r lattictfo e investigations s commissionewa , 1961n i d . After operatio o decadestw r fo n, Zerlins wa a decommissione y 1984Ma n .i d

349 Tables 1 and 2 summarise salient data on Apsara reactor and its utilisation. Tables 3 and 4 give simi- lar datZerlinr fo a a reactor, while Tables 5(a), 5(b) an presen6 d t corresponding datCirur fo a s reactor.

Table 1

APSARA (Pool type, light water moderated and cooled reactor)

Power (kW) 400 Maximum flux Thermal 7.1 x 1012 (n/cm2/sec.) 12 Fast 0 1 1. 6x Fuel t U - Al. alloy (12 plate elements)

U-235 enrichment l 93 % Reactor control/ i Four cadmium blades, shut down

EXPERIMENTAL FACILITIES

Type No. Maximum flux Use (n/cm^/sec) 12 Horizontal 2.0 x 10 Nuclear beam holes research 12 In-core irra- 7.5 x 10 Isotope diation assembly production 10 Reflector 0 1 x 0 1. irradiation

350 Tabl2 e

APSARA REACTOR UTILISATION e followinTh g summarises typical experiments conducted usin reactore th g :

. 1 Nuclear fission experiments: - Distributio masn angld ni an sf fragment o e s Prompt radiation n fissiosi n - Theoretical investigations . 2 Irradiation studie f chemicao s l compounds

3. Researc n Biologhi d Agriculturan y e 4. Neutron activation analysis: - Fast neutron reactions cross sections - Applicatio Archaeologn i n y . 5 Neutron physics experiments . 6 Experiment r Dhruvfo s a reactori Optimisation of the parameters for reactor control syste n chambeio m r basket - Shielding efficiency for neutrons and gammas innee oth f r gate f neutroso n beam tubes - Neutron radiography for reactor fuel clusters 7. Transmutation studies for doping silicon crystals for industrial applications 8. Shielding measurements for power reactor shielding components . 9 Isotope production.

351 Tabl3 e

Z E R L I N A

Reactor type i Variable fuel, heavy water moderated, uncooled

Power O watt10 t s (maximum)

Purpose » Lattice investigation

Reactor control t Moderator level

Shut down x cadmiuSi t m rodd an s moderator dump

Research facility i One cadmium shutter for bare reactor studies

Reactor decommis- r April 1984 sioned

Tabl4 e ZERLINA REACTOR UTILISATION e followinTh g summarises typical experiments conducted usin e reactorth g i 1. Lattice physics investigation: Natural uranium metal lattice - Natural uranium oxide cluster lattice 2. Experiments for Dhruva reactori

Study of Dhruva fuel lattice physics Study of emergency liquid poison shut down system Study of approach to criticality for neutron detector configuration Effect of Ü2Ü scatterer in through tubes to optimise its length 3. Experiment r powefo s r reactors:

Plutonium booste d developmenro r t Noise analysis techniques in the frequency domain Measurement f neutroo s n flud fluencean x .

352 Table 5(a)

S U R I C (Tank type, heavy water moderated, light water cooled, graphite reflected reactor)

Power (MW) t 40 13 Maximum flux i Thermal 6.7 x 10 13 (n/orr/sec) Fast 4.4 x 10

Fuel i Cylindrical natural uranium metal rod

Reactor control t Moderator level

Reactor shu C rods4 tB dovnx ] Si Moderatoi r dump

Table 5(b)

CIRUS RESEARCH FACILITIES

Type No. Maximum thermal flux x 10( 13 n/cjT>2/se) c

Horizontal hole (100 ram) 20 1.2

Horizontal hole (300 mm) 5 1.7

"Self serve" unite 6 1.7

Central thimble 1 5.9 (in core)

Tray rods (in core) 6 6.7

Engineering loops 6 5.5 (in core)

J-rods 69 1.0

Thermal column 2 (108 - 1011)

353 Tabl6 e

CIRUS REACTOR UTILISATION

Productio laotppef no s

Neutron beaiti r basifo s c researc n Physicshi , Chemistr Biologd an y y

Fuel testing and development for power reactor in pressurised water loops

Fuel testin d developmenan g r researcfo t h reactors

Neutron activation analysis

Irradiation damage studies

Man power development and training.

2. DHRUVA

Most recently, Dhruva, a 100 MW(Th) research reactor bees ,ha reactoe n th buil s madd wa ran t e critical in August this year. In the following, some details of this research reactor facility and its proposed utili- sation schemes are presented. The reactor has a vertical core and it is fuelled with aluminium clad metallic natural uranium fuel clusters e maximuTh . m thermal neutron flux wile lb 1.8 x 101 4 neutron/cm 2/sec. Heavy water is used as primary coolant to cool the fuel element in a recircula- tion circuit. Heavy wate s alsi r moderatoe o th use s a d r and reflector.

354 Fig.1 shows the general arrangement of reactor vessel in the reactor vault. Reactor vessel is located vertically insid a vaule t filled with light watere Th . reactor vesse s supportei l e botto th a suppor t n a mo d t structure and at the top on the annular shield. The vaul s mad i tf concreto es linei d d an ewit h stainless steel liner. An end shield placed over the annular shiel extendind an d p sub-shelgto e intreactoe th th of lo r vessel provides the required radiation shielding. From

11,050 DIA

END SHIELD

ANN. SHIELD

REACTOR VESSEL

DHRUVA GENERAL ARRANGEMENT OF REACTOR VESSE VAULN LI T

FIG.-1

355 each of the lattice tubes on the top tube sheet of the reactor vessel, extension tubes exten reactoe th d r dece th vessek e f plateo th p ln I to boundar. e th o t y extension tubes, guide tube e thear sn placed forming e reactoth r coolant channels extending froe inleth m t plenum to the tail pipes and further to the top of the deck plate. The fuel assemblies are then inserted into the guide tubes. Cool heavy water coolant froinlee th m t plenum is circulated through the fuel elements in a recirculat- ing circuit through heat exchangers. The heat generated in the reactor core is removed through heavy water heat exchangers through which is passed the déminera used light water, which is used as a secondary coolant. The demineralised water is then circulated through a set of process water/sea water heat exchangers, s wheri t ei e tertiarcooleth y b d y coolant a waterse e .th , Thus, the heat generated in the reactor is finally rejected e seath .o t The reactor power is regulated by controlled adjustmen f heavo t y wate re reacto leveth n i l r vessel. Shu e treacto th dow f o ns achieve ri y fasb d t insertion of shut off rods, which contain cadmium. This would be the primary shut down device. As a secondary shut down device moderatoe th , r wil e dumpeb l d froe reactoth m r vessel. In addition, as an emergency device, provisions have also been mad r liquifo e d poisoe injecteb o t n d into a set of vertical tubes arranged inside the reactor vesse o formt l callede ,b wha y tma , liquid poison rods.

Fuelling is achieved through a fuelling machine, which has provisions for changing of fuel with the reactor at power. Spent fuel is discharged to a buggy e wateth rn i filled fuel transfer reactoe trencth n hi r hall e fueTh .l transfer trench connect e storagth s e e reactoblocth n ki e spenr th hal to t lfue l storage building adjoining the reactor building. The machine is also used for handling isotope tray rods, which are

356 heavy water cooled. Other vertical experimental assemblies, which are not cooled by heavy water, are handled by another machine. The reactor vessel provides 146 lattice positions arranged in a square lattice pitch of 18 cms. Out of these, two are used for engineering loops and three for corrosio d creenan p testing facilities e remaininTh . g 141 positions are used for placing coolant channels containing the fuel assemblies, tray rods for production of radioisotopes and shut-off rods. Under typical ope- rating conditions 9 lattic12 , e position occupiee ar s y b d fuel assemblies y shut-ofb ,9 f y isotoprodsb o ,tw e tray pneumatia y b e on crod d carriean s r assembly. Some salient design data of the reactor is given in Table 7.

Research Facilitie n Dhruvasi » Fig.2 shows the general arrangement of research facilities around the core. Table 8 summarises the research facilitie e neutroth d nsan flux levels available at rate d 0 MW(Th.)powe10 f ro .

Engineering Loops: Facilities are provided for two engineering loops which could be used to investi- gate the performance of prototype fuel elements and materials under simulated operating conditiona n si power reactor e largeTh . r facilit diametea s ha y f o r 150mmaximua d man m thermal neutro0 1 x 4 n 1. flu f xo 14 m m 0 r second10 pe neutrone smallef o m Th c .e r on rs pe diamete maximua s ha r m thermal neutrox 6 n 1. flu f o x 0 1 n/c14m /sec in-core Th 2. e pressure tube f bote o s th h loops are made of zircaloy. Fuel elements and materials for testing are handled with the help of a second fuelling machine. The heat generated in the loops is removed by light water in an independent circuit.

357 Table 7

DHRUVA REACTOR VESSEL AND CORE DESIGN DATA

1. Reactor vessel main shell) Inner dia 372 cms - Height 305 cms

2. Reactor vessel lower sub-shell: - Inner dia 280 ana - Height 32 croa

3. Reactor vessel upper aub-snellt Inner did 315 cms - Height 30 cms

4. Reactor vessel overall height 387 cms

5. Coolant channel (Zircaloy guide tube ) t - Innea di r 7. 5 cms - Wall tnicknese 1 flm

6 . Fuel- Natural uranium metali - Nc . of fuel pins per cluster 7 Nos - Fuediameten pi l r 1. 27 cms - Aum1 ui lmn cladding thickness 1. 0 nun - Length 305 cms 7. Total lattice positions 146 No«

8. Lattice pitch 18 cms aquare

9. Lattice positions for creep/ 3 Nos corrosion facilites

1Û. Lattice position r engineerinfo s g loopa 2 Noa

11. Fuel positions 129 Noe

12. Shut cff rods 9 Nos

13. Pneumatic carried ro r 1 No.

14. Isotope tray rode 2 Noa.

15. Average radial reflector thicX-neas s cm 6 28 .

16. Axial reflector thickness;

- Lower 32 cma Upper 30 cma

17. Active core height 305 cms

18. Maximum operating moderator level 367 cma

19. Heavy water inventor n vessei y l 39 Te

20. Uranium inventor n cori y e 6 .69 Te

358 DHRUVA GENERAL ARRANGEMENT OF RESEARCH FACILITIES

FIG-2

359 Table 8

DHRUVA RESEARCH FACILITIES

Type No. Maximum neutron flux at 100 MW ( x 1013n/cm2/sec ) Thermal Fast

Engineering loop(151 ) 0mm 14.6 4.9

Engineering loop(10l ) 0mm 16.4 3.5 Radial beam holes(104 ) 0mm 3.8 0.4

Tangential beam holes 4 8.1 1.0 (100 mm) Radial beam holes 7.0 0.4 ) (30mm 0 Cold neutron source 1/1 13.4 2.2 (30O mm/300 mm)

Hot neutron source 1/2 14.3 2.4 (300 mm/10) 0mm Upper through tube 8.1 2.9 (100 mm) for isotope production Lower through tube 1 16.3 5.8 wit) (10mm h0 scatterer Pneumatic carrier 1 18.4 4.5 facility Isotope tray rods 2 17.7 4.1 (in core)

360 Horizontal beam tubes numbeA ; f horizontao r l beam tubes distributed around the reactor core provide ac.ces higo t s h neutron fluxe r beafo sm researcd han irradiation experiments. Ther e fouear r radia d fouan l r tangential beam tubes of 100 mm dia, which provide ther- mal neutron beam r researchfo s . Besides, there ear five beam diam m0 ,tube 30 fou f swhico f o re radialar h .

Cold neutron source: One 300 mm diameter beam tube placed at a slightly off-radial position is used for inserting a liquid methane moderator maintained at about —160 C to provide very low energy ("cold") neutrons. m diametem 0 30 re th radia Onf o e l beam tubes facine th g cold methane moderato extracn ca r cole th td neutrons. Through neutron guides mad f nickeeo l plated optical glass cole /th d neutron e extendeb n ca s d int guidoa e tube laboratory adjoinin reactoe th g r building.

Hot neutron source: Anothediam m 0 . radia30 r l beam tube is used to place a block of thermally insulated graphite exposee neutronth o t gammd san e a th ray n si peripheral e coreregioth .f no Nuclear heatino t e du g gamma rays and neutrons hitting the graphite block main- tains its temperature at about 1325 C. Neutron beams from the hot source can be brought out from this tube a satellitdi m m a s0 ewel 10 tube fros o a l tw ms which look sourcee ath t .

Through tube beam holes: There are two "through differeno tubestw t "a t heights passing froe sidmon f o e the reactoothee th ro t ralon crose chora gth sf o d section of the calandria. At the centre of the lower tube, there is a compartment of heavy water, in communi- cation with the reactor moderator, which acts as a secondary source of scattered neutrons. The lower through tube is used for neutron research. At both uppee th end rf o sthroug h tube self-serve facilities are provided to irradiate samples. Samples to be irra- diated are loaded into a carrier tube which is mechani-

361 cally pushed intreactoe th o r core. After Irra- diation, the samples are withdrawn and allowed to fall int shieldeoa d receptacle.

Pneumatic carrier facility: X pneumatic carrier facilit provides i y r shorfo d t time irradiatiof no samples e sample irradiateb Th .o t e s sendi t inte th o pneumatic carrier rod and retrieved after irradiation, fro laboratora m y located outsid reactoe th e r building, u ai no; compressed air. This facility is useful in the stud f short-liveo y d fissio activatiod an n n products.

Isotope tray rods; Dhruva enables large scale productio radioisotopef no s with high specific acti- vities. Samples are irradiated in specially designed tray rods. A tray rod can hold 72 capsules of 2.2 cm diameter and 7.5 cm length containing samples for irradiation. The tray rods are installed in fuel channel requireds a s e coolear y d heavb d,an y water. e on-poweTh r fuelling machin s user loadinei fo d d an g unloadin e trath y f rodsgo .

3. ISOTOPE PRODUCTIO TROMBAT A N Y Radioisotope production starte Indin i d a soon after commissioning of Apsara reactor in 1956. Apsara reactor enabled production of a number of radioisotopes of short half-life. Following the commissioning of Ciru n I960si , productio wida f eo n variet f radioo y - isotopes became possible. Long-lived isotopes suca ha Cobalt-60, Iridium-19 hosa othef d to an 2 r isotopes required in large quantities for applications in industry, medicine and research are being routinely produced e maiTh n. radioisotope products presently available fror isotopmou e production programme ear indicated in Table 9. with the commissioning of Dhruva, the isotope production capability in the Centre will increase

362 Table 9

PRODUCTIOF O N RADIOISOTOPES IN RESEARCH REACTOR T TROMBAA S Y

Isotope Half-life Production End use millicurie per year 124 Antimony-124 60 days 40,000 r Fo Sb-Be neutron n i e sourcus r fo e research. Bromine-82 32 hrs. 400,000 Tracer application in industry. Calcium-45 153 days 500 Trace n agriculi r - turresearchd an e . Chromium- 51 27.8 days 2,400 Nuclear medicine Cobalt-58 71 days 400 Nuclear medicine Cobalt-60 5.27 year« 100 KCi/yr Radiation therapy, industry & research Gold-198 7 day2. s 3,500 Mediclhe, indus- trial tracer Iodine-131 8.04 days 300,000 Nuclear medicine Iridium-192 74.4 days 17 KCi/yr Industrial radio- graphy Mercury-203 47 days 5,000 Nuclear medicine Molybdenum- 9 9 67 hrs. 300 , 000 Nuclear medicine Phospho- 14.2 days 25,000 Agricultural research rous-32 (Apsara) and Bio-medical application Rubidium-86 18.7 days 1,200 Industrial tracer, research Sodium-24 15 hrs. 5,000 Industrial tracer, nuclear medicine Sulphur-35 87.2 days 5,000 Agricultural research, research in Life Sciences Service - 1,500 For research in irradiations samples Physico-chemical Life Sciences Mercury-197 65 hrs 5,000 Industrial tracer studies.

363 many-fold. Thus the increasing demand for radioisotopes used in radiation therapy and in nuclear medicine such s Iodine-131a , Chromium-5 Molybdenum-9d 1an r medicafo 9 l diagnose e metb n . ca s Iodine-125 importann a , t radio- isotope used in radioimmunoassay which is at present being imported will als e produceob n Dhruvi d n adéquati a « quantities. Iridium-192 with high specific activity require e fabricatioth r fo d f intenso n e gamm y sourcera a s use n compaci d t radiography cameras will als e produceob d in Dhruva. The estimated productio f somo n e important radio- isotope n Dhruvi s a reacto s indicatei r n Tabli d. 10 e

Table 10

ESTIMATED PRODUCTION OF SOME IMPORTANT RADIO- ISOTOPE N DHRUVI S A REACTOR

Isotope Half-life Annual pro- End use duction Curie/year

Carbon-14 5505 0 year« For preparation of labelled compounds use s tracera d n i s life sciences. Molybdenum-99 67 hours 1000 Nuclear medicine (high «p. activity) Chromium-51 27.5 1 8 days Nuclear medicine Iodine-125 60 days 30 Nuclear medicine

Iodine-131 8.04 day« 1500 Nuclear medicine

Iridium-192 74.4 days 3000 Industrial isotope (high sp. radiography. activity)

364 4. NEUTRON ACTIVATION ANALYSIS (NAA) One of the Important uses of research reactors has been their utility as a source of neutrons for activation analysis. Studie n activatiosi n analysis using reactor neutrons have been pursue n Indii d a using Apsara and Cirus reactors. The applications have been materialn i s science, earth sciences, forensic, environ- mental and life sciences and archaeology.

NAA Applications; Material Science: Applicatio materian ni l science can be considered in four major areas resourc) (1 e prospectin procesd an g s development, (2) development of new materials, (3) compositional characterisatio materialf no performanc) (4 d san e of fabricated components.

prospectine Th uraniur fo g delayey mb d neutron counting, analysi f uraniuso impuritier fo m s like rare earths and analysis of cladding and structural mater- ials for specific elements are examples of our work in the application to atomic energy programme. The characterisation of high purity material like silicon for heavy metal impurity at ppb levels of concentration, profiling gold diffused into germanium etc are examples of our experience in the application to electronics. e epithermaTh l neutron activation providea s viabl ee analysi methoth r fo f puritdo s n materiali y s like Ag, Ga, In, which have large thermal neutron activation cross shielding problem. Archaeology: Potsherds and metallic objects including bronze e artefact th e som sar f eo s studied by activation analysi n combinatioi d an s n with multi- variate analysi e data th e studie th ,f so s have revealed valuable insights intarchaeologicae th o l aspects lik« provenience and movement of cultures, in addition to authenticating the art treasures.

365 Forensic Science e applicatioTh ; o forensit n c science can be considered in three na jor categories, viz) determinatio(1 . a specifi f o n c poisoning, ) determinatio(2 specifia f o n c grou f elementspo l al , r somo whicf eo requiree e ar solutioh e th th n i do t n ballisticn i , Hg d , san Sn , Cu , Ba , Sb proble , pb s ma ) determinatio(3 a numbe f o nf element o r s (not knowa n priori) to generate features or a pattern that will help establis e commonnesth h o f origi(groupso tw f no s ) specimenof s (from scen f crime o suspecd an e r controlto ) Environmenta d lifan le sciences; Multi-element analysis at trace levels on small amounts of samples has enabled the monitoring of the pollutants in all spheres of the environment. The combination of multi- element data and pattern recognition analysis has helpe establishinn i d g human hea dn effectiva hai s a r e first level monitor, in a multi-level scheme of monitoring the exposure to (inorganic) pollutants and assessing the body burden.

5. RESEARCH REACTORS AND MAN POWER DEVELOPMENT The introductio f nucleao n r energy invariably involves indigenous competenc n nucleai e r technology, which has a character distinct from other industrial technologies e majoTh . r constrain r achievinfo t g rapid progres developina n i s g countr n nucleai y r power generatio e readth ys i navailabilit f o y indigenous technological suppor trained tan powern ma d . A research reactor providee s th man f o y essential system a nuclea f o s r power statio d enablean n s the scientists, engineers and technicians to acquire first-hand experienc handlinn i e g radiatio gaid an nn expertise in the technicalities of controlling nuclear chai r nexperienc ou reacton s i t I e. that engineers and scientists trained in research reactors have shown a greater awareness of safety considerations in manag- ing power reactor systems. Utilisation of research

366 reactors for research in basic sciences in the disci*- plines of physics, chemistry, metallurgy and production of radioisotopes for use in medicine, industry and agriculture have acted not only as a catalyst for the development of advanced technologies in a variety of fields alst bu ,o have enabled generatio f scientifino c man power.

Reference ;

. 1 Gangadhara "Trend, . S n d Developmentsan e th n si Application of Nuclear Activation Analyses", presente internationan i d l symposiu artin mo - ficial radioactivity, Pune, India, Jan.1985.

367 INCREASED UTILIZATION OF RESEARCH REACTOR FACILITIES WITHOUT PERSONNEL EXPANSION BY A USER-FRIENDLY SYSTEM FOR ROUTINE INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

P BODEBRUINE D KORTHOVEM J M , P. , N Interuniversity Reactor Institute, Delft, Netherlands

Abstract

In order to exploit with sufficient efficiency an expensive tool as a nuclear research reactor, at the I.R.I. scientists from the applied fields are being encouraged and enabled to include nuclear methods in their own (non-nuclear) research projects. This has extensively been worked out in the IRI-system for routine instrumental neutron activation analysis. Thi se b use systey guestsb n d ca m , withou a priort i knowledg f o activatioe n analysis, after only a short instruction period By this approach the use of the des- cribed analysis system has resulted into a strong increase of the use of the reactors's irradiation facilities withou e nee r th expandint fo d e permanenth g t staff

INTRODUCTION

Research reactors, even thos f o smale r o mediul m sizee expensivar , t powerfubu e l research tools, applicabl n mani e y sciences When considering suc a hreacto a sourc s a r e of neutrons for e.g. neutron scattering and diffraction studies, or for activation, its potential largely exceed e researcth s h capabilitie e permanenth f o s t staff o specialistf s t a most institutes. Therefore, many reactor institutes e faccommoth e n o t proble w ho m exploit such an expensive tool with sufficient efficiency A realistic approach to a solutio f o thin s proble o t encourag s i m d enablan e e scientists e froapplieth m d fieldo t s apply themselves nuclear method n i theis r research projects. Such scientist y includma s e not only physicists and chemists, but also biologists, physicians, geologists, archaeolo- gists etc., who have in genera! little knowledge of nuclear physics or radiochemistry Therefore, both on-the-spot training and experimental procedures have to be adapted to laymen, which use nuclear techniques on a part-time basis and only as an aid in their non-nuclear research. Moreover, extensive attention has to be paid to procedures for assurance and control of the quality of the analytical results. The present paper describes how this approach has been worked out in the system for routine instrumental neutron activation analysie th t sa (I.N.e ) us develope n A i d an d I.R.I. at Delft. This institute has to make its 2 MW swimming pool reactor and related facilities available to the Dutch universities The chemistry department has to cover the major part of the demands for activation analysis existing at the Dutch universities.* As can be observed worldwide also in The Netherlands there is a still increasing demand for ( trace)element determination h Inter6t e y nINAAb th s n Con t 198I n a Modero . , f1 n Trends in Activation Analysis Girardi concluded thao morn t e modern trend n activatioi s n analysis coul e foreseeb d d thaan nt N.A.A d reacheha . a dpoin t d becomwherha t i ea eroutin e ana- lytical technique like many others (ref.l). Therefore, the IRl-system for INAA

Because of legal regulations the Institute's efforts are restricted to institutions of higher education This exclude e existencth n INAs ow A f o eservic e g activitie e r fo s industry, which in other comparable institutes is often regarded to be rather proitable,

it is now been done by a separate Dutch organization using the Institute's reactof r and related facilities, and applying partly the here described INAA procedure The^e act ci- ties, allthough also continuously increasing t includeno e n ar thii d, s surve s a theyo d y not involve any concern of the IRI-staff

369 ( developed and sel-up in the 1970-ies) has been stripped of its mystic and brought to, as s faa availabilitr d ease-of-operatioan y s i concernedn e leve th f o ,othe l r 'push-button' method d apparatus an se scientifi th n I .c research prograe IRI-grouth f o m p involved, ini- tially comprising development of INAA as a principal task, merely limited time and man- power by the permanent staff is reserved for maintaining the routine-system up-to-date. Their scientific effort is now put into research in which use and interpretation of trace-element data obtaine y INAb d A pla n importana y t role. Moreove e capacite th rth f o y system is fully exploited which has a favourable effect to analysis'costs. e varietTh f o scientisty s thus acquainlained e witopportunitieth h f o nucleas r research reactor d relatean s d facilitie t goinse s a gfavourabl e publicit e expandinth y n aboui t i tg field of applications, and, depending on the topics studied( e.g. problems concerning public healt r environmentao h l matters a certai o t ) n extent als n publio c opinion. In this paper, attention will be paid to some of the starting points of such a laymen's differenw systemho d an t , items were brought into practice.

I SYSTEIR ROUTINR E MFO TH E I.N.A.A.

e routinTh e instrumental neutron activation analysis system (refs.2,3,4) processes sev- eral thousand samples per year. In normal procedure, each sample is measured three times e semiconductoth f o e witon h r detectors. This implies that, together e witnecessarth h y standards, around 15000 measurements have to be carried out per year. Because of the lim- ited manpower available (the syste s i effectivelm y operate y e onlb analisO.ad on y n effi- cient software package is highly desirable to decrease to a large extent the need for man- ual intervention durin e e coursanalysisth th g f o e . To the users of the system a manual is provided with a step by step description of the analytical procedure d alsan o,e computeth includin f o n e rintroductioa gus syste e th m o t n d discussioan e problem th f moso nf o t s commonly encountere n INAAi d . Several measuree ar s e provideprocedurth n i do t detece t erroneou so t eitheresult e rdu s instrumentad an l software failures r o mistakee analyst,th f o s . Reference material e regularlar s y analyzed to verify the quality of the reported results. Special techniques focussed on the detection of one or specific element(s) are only included in the routine INAA-system if they do not affect significantly the overall per- formance (including e.g. ease-of-operation, analysis' costs, capacity). Oftee th n methods (e.g. use of the low-energy part of the photon spectrum and associated correction for self-absorption, or the use of epithermal NAA) have allready been developed; implemen- tatio f o thesn e methods will onl e considereb y e interestinth f i d g customers provide addi- tional man-power to carry out the required calibrations.

Standard protocol

The analysis system is based on the use of the single comparator method, to take full advantag e multielementh f o e t capabilitie f o INAs A withou e problemth t s associated with f o e standardpreparatioth e us d s an coverinn e periodi th o thir f tw o gd c system. Zins i c being used as comparator element. The analyses are performed according a standard proto- col of a first activation of 10 - 30 sec followed by measurement after 0.5 - 20 m decay, and a second activation of 0.5 - 4 h followed by two measurements after 3 - 6 d and 3-5 w respectively e maximuTh s . beeha m nh irradiatio chose4 o t f avoio e n nth d time-consumin f o quart e us zg ampoules e applieTh . d decay time depende typth f o en o s material (Al- ,Na d Br-content-an e analyzedb o t ) .

Automated measuring equipment

Four spectrometers are in use for I.N.A.A. : two spectrometers with coaxial Ge(Li) detectors, one spectromeler equipped with a well-type Ge(Li) detector and a separate spec- trometer with Ge-detector connected wite fast-rabbith h t system.

370 e spectrometerTh 4 compute/4 1 e 1 integratear sF r PD wit C dh DE witextende a h d memory through buffered input gatea CAMA n i s C interface system. An analysis technique that functions with optimum economy e ask th r maximu f fo so e mus expensive equipment involved. Therefore that the measuring equipment should be active 24 h a day,? days a week, and the counting time per sample or standard should be selected carefully. This can be accomplished through the application of computer-controlled sample changers. e sampl r Th laboratorou en i changere self-designee ar yus n i s d pneumatic systems that allow for an appreciable distance between the active sample store and the measuring equip- men o avoit t d interferences (. ) refs5 The , e alsF 11/42 . ar yo PD couplee 4 th compute o t d r through CAMAC modules. An outline of the hardware organization is presented in fig.l .

COMPUTER

. FigSchemati1 . c lay-oue spectrometerth f o t s r routinfo e ius en I.X.A.A.

Analysis software system

In many years of experience with an automated computer coupled measuring system for INAA of large numbers of samples, we have seen that manual administrative procedures soon e formosth m t laboriou e analyticasth parf o t l procedure. Apart e frosoftwarth m r fo e control of the measurements and for data handling, a computerized administrative procedure s wa develope n i whicl dal informatioh ne th analysirelevan r fo s t (sample codes .weights .irradiatio d measurinan n d ge intcompute fe th timeso e d ar storean ) rn o d disk as soon as they become available. The INAA software package contains the following components ( ref .6 ) : • software for the control of the spectrometers and sample changers • an automatic on-line Ge(Li) f-ray spectrum analysis program • an interpretation program, coupled to the spectrum analysis program, to reduce the calculated f-ray data to isotopes present in the sample and corresponding element con centrations • software to compare and combine results from measurements at different decay times and/or from different irradiations and to generate analysis reports to the customers • software for communication between the various components of the software system • program o generatt s e status informatio e analysith r n internao fo ns e progressus l d an , on the use of the equipment • a quality control program for bookkeeping results from reference materials for detection of systematic e erroranalyticath n i s l procedure.

371 The main information flows in the software package are shown schematically in fig - 2 .

AND

AMALYl/S MFTWAJtf

Fig . 2 Mai. n informatio N A.A.-systI. ne flowth n ci s

Manual

The users of the analysis system are provided with an extensive self-explanatory manu- al. This 60-page manual comprises a short introduction to instrumental neutron activation analysi s a implementes t a IRId . Detailed instruction e give ar r ssampl fo n e packinge us , e automateth of l dcomputeal spectrometerf o e r us program d an s s needed durin e analysith g s process. Much attentio s beeha n n pai o limil d a descriptiot e computeth f o n r systed an m s it user interface subjectth o t es necessar r e carryinanalysesth fo y t ou g . Commonly encountered problem d theian s r solution e discussee ar e sRSX-11textth Th n .i d M "Help"-facilities have been extended with information abou a numbet f programso r , involved e analysisth in o t ,provid e instant r assistancexperienc ou e terminal th s i t t a I e e . that novice user e abl ar o st operat e e systeth e m using this manual shortly after enterine th g institute .with very little assistance.

QunHty of the results

Quality of the results is a matter of major concern in systems for routine analyses to e useb e y firslaymenb dth t n I contact. s with potentia a userw INAA-system f ne lo s e th , established qualit f o routiny e analysis will often been use o t emphasizd e possibilith e - e techniqueth tief o s . Accurac d precisioan y e oftear n n a measuruse s a d e indicatine th g performance. However, these parameter t onlno sy e depenprocedurth n o ds s a sucha et bu , well on the professional skill of the analyst. Initially the quality was established by specialists with often many years of experience. For a laboratory, inviting and enabling non-radiochemists to carry out activation ana- lysis , it is of the utmost importance that accuracy and precision of the thus obtained analyses'results reflect a realistic situation; a reputation carefully build-up over many years of being a laboratory where good results can be obtained, can rather quickly be lost. r routinIou n e INAA-system several check e providear s d (réf ) amongs4 . f o e t us whic e th h standard reference materials pla n importana y t role. Along with each serie f o samples a s reference materia s i analyzedl e resultTh . s from these analyse e handlear s d wit a hspe - cial administration program providing for each certified element the mean of all results so far, the mean of the last ten results and the most recent observation. These figures give insight inte e e accuracqualitlasth th th o t f d o analysisyan y e referencTh . e mater- e ialselectear s d from materials .USGS.IAES provideNB y b d A etc. e similarin th basio , f o s - y witt e sample th he analyzed b o t s .

372 Table 1 shows as an example for part of the elements observed the results obtained in 15 analyses of USGS MAG-1 . The analyses were carried out by a technician, a geologist. and a soil-scientist in the course of one year. For control of accuracy, the experimental determined concentration e comparear s d wite datth h a reporte y Steinneb d t sI (réf . 7) .

•can •ean Elc concentration Steinnes (ref.7) Element concentration Steinnel (ref .7 ) « Ipp n PP" In pp« PP"

Na 27900 4 200 28000 Rb 151.1 4 1.9 170 Al 87600 4 5500 88000 Cs 9.90 4 0.14 8 K 28300 4 500 30000 Ba 497 4 16 490 Se 17 .08 i 0.06 17 La 46.7 ^ 0.3 50

Cr 102 .6 4 0.9 110 Eu 1.52 4 0.03 1.6 Mn 775 4 16 770 Yb 2.41 4_ 0.06 3.0

Te 47100 4 200 47000 Hf 3.59 i 0.03 3.7 Zn 128 4 5 130 Ta 1.02 + 0.07 1.0 As i II .1 0.3 10 Th 11.89 4 0.10 i2'6 Br 218. .3 4_ 1.9 — U 2.67 4 0.14 2.8

Table !. Results obtained in the analysis of USCS-standard HAG-1

demonstrates thae e qualitresultth th t f o ys obtaineuserw ne s aboui s y e samb dth s t a e those obtained by more experienced users.Fig. 3 shows for different elements the results of MAG-1 analyses, obtained ove a longer r period.

c Sc o c 1.05 •E 100 £ 0.95 u c o o

S 1.05 -E I.OO a • o E 0.95 W O Z 1 1980 1981 1982 1983 1984 1985

Irradiation date (year)

FIR. 3. Results fur Sc Jnrf FL* in MAC-1, ntumn l j /cd to ] . 00 fur the rrcomnonded vu ] ue

373 Capacity

r mosFo t sample e maximuth s m counting e zinc-standartim th s i limitee 1 hou d o an t rd d is measured appr. 15 minutes. Therefore, the available instrumentation allows for mul- tielement analyses of more than 5000 samples per year. The maximum working time required r analyzepe d sample bein e houron g a ful, l tim e eINAA-syste th use f o r n handlmca e about 2000 samples per year. In practice 3000-4000 samples are analyzed annually with the routine system e actuath , l limitation bein ge availabilitth excep r fo t f o samplee y th r o s time require r samplfo d e preparation merel e scientifith y c interpretatio e resultsth f o n . Very recently a second spectrometer with well-type Ge-detector has been installed which will increase the annual capacity of the IRI-system for multielement analyses up to 8000 samples.lt can be concluded that the capacity of the system covers the existing demand for instrumental neutron activation analyses at the Dutch universities.

Ease of operation

w radiologicaAlne l l worker e I.R.Ith t a s . hav o follot e a wtwo-da y cours n radiao e - tion, radiation-protection and health physics before starting with their research pro- jects . As has been pointed out earlier the INAÄ-system is intended for users not specialised in radiochemistry. This implies tha a trainint g perio s i necessard t thibu ys period should be short for efficiency reasons. In practice, new users of the analysis system are abl o t stare t their analyse f so instructio aftey da r e onln on ywhil e thee furthear y r tutored during the course of the whole first analysis. After that they are able to ana- lyse their samples almost independently e INAA-syste witth e hel th f h o p m manua d onlan l y incidentally n assistea experience y b d d radiochemist. Afte a shorr t separate training thee alsar yo allowe o t perfone dcomplet th n n theio n ow er analysi n whici s h short-lived nuclides are being used, including the irradiations with the fast rabbit system. Because of legal regulations, the other irradiations are restricted to members of the permanent staff.

Analysis costs

s i recognizeIt d e thaexperiencth t e wit a hspecifi c procedur a universit n i e y associ- ated research laboratory is an unreliable basis for making a cost estimate of such a pro- cedure. Moreover, great care mus e takeb t n when comparing cost estimate r governmentafo s l and industrial laboratories or laboratories in different countries. Still, an cost esti- e IRI-systeth mat f o e r routinfo m e INA s beeha A n made n whici ,e followinth h g coste ar s distinguished (réf. 3) : • labor costs, including overhead and use of genera! facilities • cost f instrumentatioo s n specifie INAth Ao t c facility • small expenses directly related to an analysis. The labor costs are estimated on basis of the amount of work required for the analysis n hour ma e coste sampler .th on o pe fsd Thes an e calculate, ar e d froe annuath m l Insti- tutes budget (except costs for scientific instrumentation) by dividing it by the number of people actively participatin n i scientifig c research. Suc n a estimath e include l cost'al s ; except depreciatio f buildino n d reactoran g d INAAan , , system development costs n thiO s. basis the labor c usts per sample were estimated as Dfl 50-100V. The costs of instrumentation specific for INAA comprises the costs for counting equip- mend computinan t n gannuao e facilities assume, ar be l d basio t an d , s including service costs, 30/i of the initial investment. This leads to a contribution to the analysis costs of Dfl 50 for 3000 analysis per year, and Dfl 35 for 5000 analysis per year.

Because of the rapidly changing exhange rate between the Dutch currency (Dfl) and the U'J $, all figures are quoted in Dfl. Over the past year, the exchange rate varied from Dfl . « S U r pe 9 3. o t 0 3.

374 e smalTh l expense e primarilar s y cost f samplo s e capsule r d laboratorrabbitsou an s n I . y these cost r samplee lespe ar s s 5 thal . Df n On basis of 5000 analyses per year, the analysis costs per sample can be summarized to be : hou1 r sampl - pe r 5 elabo0. : r Dfl. 50 - 100 instrumentation and computer Dfl. 35 small expenses Dfl. 5 total cost r analysipe s s Dfl. 90 - 140 With respect to costs the IRI routine systee regardeb r INAn fo m ca s Acompetitiva d e with other analytical techniques. The development costs of the IRI-system for routine INAA have been evaluated by de Brui e labounTh (réf r. investmen) .8 s estimatewa t t Dfla d . 6000.000,-. Howevee th s a r development of the routine system lead to a reduction of the costs per analysis by a fac- tor 6-10, about 7000 analyses woul e requireb y dbace laboupa th ko t dr investmentt I . demonstrates that total development costs nor should be underestimated, but neither should be overrated.

USE OF THE INAA-SYSTEM DURING 1976 - 1985

The system for routine INAA was adapted to the use by laymen starting in 1978. From that time the software package was gradually increased, and the manual was developed. In 198e Institutes'regulationth 0 s were change o s thad t .afte n a appropriatr e training, guests were allowe o t perford e completth m e fast-rabbit irradiatio d associatean n d ana- lysis on their own. Table 2 gives both for IRI-group members and for guests, the number of fast-rabbit irradiations and the number of 'regular' irradiations of 16 samples each ; the involved 'input' in man-years by IRI-personnel and the number of guests using the routine system d theian r educational background.

numbe f fast-rabbio r t number of regular i rradiations irradiations IRI-input number of educational IRI-group guests IRI-group guests (manyeers) guests background guests

1976 889 33 2 1977 1494 55 2 1978 1281 62 31 1.5 1979 1922 100 147 1.5 a.b.c.d.e.f 1980 744 459 65 132 I 9 a.b.c.i.e. ,g 1981 6 34 724 45 72 0.5 9 •.b.c. g 1982 413 753 55 86 0.5 9 a.b, .i.e.h , 1983 654 1126 30 193 1 12 . ,e g.h,d , c , . • i 1984 7 69 1614 56 172 0.7 15 •,b,c,d,e, ,g.h.) 1985* 126 1204 22 50 0.5 11 a, ,c,d.e. ,g,h, ,k

• jan.-Jun '81 and a. chemistry, MSc. (analytical ehe»., ehe«, technology) o reactot e •ug-dedu r 2 sto'8 cp b. chemstryc BS . . biologyc c BS , *• calibration of spectrometers united d. cheuistry, technician f routino e us e INAA-systen; t. geology, technician 5 '8 n JanJu - . . agriculturef , technician g. geology, HSc (geochenistry, sedloentology} h. biology MSc (botany, ecology, environ«, sciences) i. physics, BSc . physiciansk , technicianc HS d an s

Table 2. Use of the I.R.I.-system for routine l.N.A.A. 1976 - 1985

375 From 197 e capacit7 r th INAA-systeou f o y s remainemha d unchanged n 197I . e numbe9th r of irradiation d analyzean s d sample s beeha s n triplicated (see tabl. 2) whil e numbeth e r of analyse e IRI-personneth s y b carrie t ou d l remained allmost unchanged e timTh e . spend by the group's technician in routine INAA affairs could effectively be reduced, also because of the developed administrative programs. A great relief for the IRI-group was attained whee guestth n s starte o t operatd e themselve e fast-rabbith s t irradiation system. This coincided with a rapidly increasing demand for analysis by short-lived nuclides, e.g. for prospection purposes The educational background of the users of the routine system varies from technicians to graduate students and post graduates; their scientific background is also rather wide spread (tabl . 2) eBot h aspects demonstrat e versatilitth e f o sucy a hroutin e system, emphasizing once more that, provided the INAA facility is adapted. no particular chemical, physica r o radiochemical l skillnes s i requires r analysifo d s performed accordina o t g standard protocol. These various scientists also calle e group'th d s attentioe existencth o t n e within dif- ferent nationa d internationaan l l organization e applieth n i sd fields f o fund r , spefo s - cial or joint research projects . In several cases a succesfull appeal to these funds was possible. As can been seen from table 3 for IRI this lead to a substantial supplement to the regular annual budget for the INAA facilities In this way the state-of-art of e.g. e K-rath y spectrometer n mucca s h more easie e kepb r t up-to-date

n powema r from grants (Dfl) fro« estimated regular annual external fundb external funds budge r INAA-fac111fo t 1y (Dfl)

1970 - 80000 1977 - - 8OOOO 1978 1 - 80000 1979 1 10000 70000 2 2WO1980 O 75000 I 19823001 0 75000 I )82 80000 - - 80000 1983 lr>34 38OOO 8OOOO IISi 2 WOOO 80000

Table 3 Survey of additional grants for INAA-fncll11ies and relation to regular annual budget

From tim o t e timIRI-stafeth e s i approachef y guestb d s with request r specififo s c ele- ment determinations, sensitivitie r o sampl se standarth et fi type dt no sprotocol thao d t . n individuaA l deviation e froroutinth m e procedure often implies additional experiments, and it may easily disturb the use of the system by other guests The general policy is to keep such special analyses to an absolute minimum Either an alternative, non-nuclear analysis techniqu s i proposee guesta th compromi r o o t d, s i mad sp whicu e h doet no s interfere wite routinth h e procedure The multi-user character of the analysis system and the resulting high degree of occu- pation of the different spectrometers lead to a complex schedule of irradiations and asso- ciated measurements. Surveyabilit n i this yi achieve sa convenien y b d t visual planning and reservation system. In addition, a very reliable performance is required of the f-raY spectrometers, the sample changers and the associated PDF 11/44 computer and CAMAC-interface, technical and electronic maintamance is carried out by the group's tech- nicians. Durin e th perio gf o consideratiod e th thun s obtained availabilite th f o y IRI-routine system has been better than 9054 A secondary spin-off of the easily accessibility of a nuclear technique like described in this pape s i thatr , becaus f o theie r presence nucleath t a er research laboratories, guests also get better informed on the possibilities of other nuclear methods and facili- ties e reactorrelateth o t n t dincreasei leada f ; e.go o t s e .us d radiochemical N.A.A., autoradiography, radiotracertechmques and thus of the reactor.

376 CONCLUSIONS

Recent evaluations of the IRI-system for I.N.A.A. learned that the described approach s madha e I.N.A.A. effectively availabl o t scientiste t specializeno s n i radiochemistryd . With the help of an extensive manual, guests are able to start their analyses after a one day instruction. This implies that efficiency is maintained even for research projects involving the analysis of only a small number of samples. The development discussed in a e considerablInstitute' th o t f thi o d s le e spape us es facilitie ha e increasr th f so e without expansion of the IRI-staff. The increased number of irradiations implies a more e reacto th a sourc efficienf s o a rf neutrone o e us t r appliefo s d research.

REFERENCES

1. F. Girardi, Radioactivation analysis. Past achievements, present trends and perspec tives for the future, J . Radioanal .Chem . 69, no.1-2, (1982) 15-25 . 2 M.de Bruin .J M . Korthove. P , n, Computer oriented syste r nondestructivfo m e neutron activation analysis ,4 (19721 Anal.Chem . no ) , 2382-23844 . 5 . 3 M.de Bruin, P.J.M. Korthoven . P Bode, , Evaluatio a syste f r o routinn mfo e instrum ental neutron activation analysis Radioanal. J , . 1-2no ,, . Che(198270 m . ) 497-512 4. M.de Bruin, P. Bode, P.J.M. Korthoven, A laymen's sytem for instrumental neutron activation analysis, Kerntechnik 44 supplement (1984) 683-689 . 5 M.de Bruin, P.J.M. Korthoven, CAMAC-based instrumentatio a non-destructiv r fo n u ne e tron activation analysis system, J . Radioanal .Chem . 22 (1974) 131-138 . 6 P.J.M. Korthoven, M.de Bruin, Computer aspect f large-scalo s e routine instrumental neutron activation analyses, Proc.Conf.Computers m Activation Analysis and 7-ray Spectroscopy, Mayaguez, Puerto Rico, (1978), 639-651 7. E. Stemnes, Pure Appl .Chem. 53 (1981) 903 . 8 M.de Bruin, Instrumental neutron activation analysi a routin - s e method, thesis, f Unwo . Techn. Delft. (1983).

377 ORGANIZATION OF A MEDIUM THROUGHPUT NEUTRON ACTIVATION ANALYSIS LABORATORY FOR GEOCHEMICAL EXPLORATION SAMPLES

R.J. ROSENBERG, M. LIPPONEN, L. VÄNSKÄ Reactor Laboratory, Technical Research Centr f Finlandeo , Espoo, Finland

Abstract

Instrumental therma d epithermaan l l neutron activation analysin ca s be used tor the analysis of 42 different elements in solid geochemical samples. At the Reactor Laboratory about 15,000 samples are analyzed annually by gammaspectrometric activation analysis and 4,000 to 20,000 by delayed neutron counting e numbeTh . f elemeno r t determination mors i s e than 300,000 annually e cosr samplTh pe .t e varie0 5 d san betwee0 1 $ US n tor normal activation analysis and is US$ 2 tor delayed neutron counting. In the following the organization of the work now and in the near future is discussed.

INTRODUCTION

At the Reactor Laboratory neutron activation analysis is used on an analytical service basis wid.A e variet samplf yo e type analyzee sar d for research institutes, universities, private companies and private people mainl Finlann yi Swedend dan . More tha differen0 n5 t elements have been determined. The annual number of samples is of the order of numbee 20,00th elemenf d ro 0 an t determination abous si t 300,00r 0pe annum. More than 95 % of the samples are of geological origin. The average cost per element for the customer is US? 0.7. The manual work is performed by one chemist with an academic degree and three laboratory technicians bees ha nt .I necessar emploo yt y automatioo ns as to achieve this capacity and cost. Because suitable instrumenta- tion is not available catrnercially the appropriate had to be develope Laboratory e build th dan t ta significance .Th autoe th -f eo matioillustratee b n facne ca th t y d b thamanuae tth l work needer to d samplee performee b th e n l on sca al y f db o analysie % th 8 9 f so samplee th f personanalysie o s rese th % whic th r t2 .f Fo so h cannot be incorporated int routine oth e procedure persono stw needede sar .

followine Inth organizatioe gth instrumente th wor e d th kan f no s which were developed wil describede lb . Furthermore developmene ,th t work currently described s i unde y rwa .

379 THE ANALYTICAL TECHNIQUES

All kinds of samples are analyzed. They are connected to mineral exploration, geochemical research, environmental research, electronic and metal industry, nuclear industry, stable tracer investigations, medicine, occupational health, biology, archaeology, forensic investigations and the control of foodstuffs. Several post-, and preirradiation radiochemical separation method employede sar t ,bu determinatione morth f eo % tha 9 n9 performee sar instrumentay db l neutron activation analysis thereford (NAAan ) e only thi deals si t with here.

Uranium is analyzed by neutron activation followed by delayed neutron elemente countin th rese Th f t analyzeo e . sar g3/ (DNAA, 2 y db , )/I instrumental thermal epitherma(INAAr o / )/4 l (ENAAneutro/ 6 , )/5 n activation analysis accordin scheme th Tabln o ei gt . e1

analysie TablTh . e1 s sequenccomplete th r efo e analysia f so geological sample. T - thermal neutron, E - epithermal neutron, C - coaxial detector, L - low-energy photon detector.

Irradiation Decay Measurement Elements

T 1 min 2 min C 5 min AI, Ti, Mn, Mg, Ca, V T 5 min n mi 0 3 n mi L 0 2 üy T 1 h 24 h Cn 20mi Na, K E 35 h 5 d C 20 min As, Sb, Zn, Sn, Ag, W, Mo, Au, La, Sm, Ni, Fe, Co, Na, Sc, Ba, Cs, Rb, Ta, u, Th, Br T 35 h 7 d C 1 h La, Sm, Yb, Lu 30 d L 3 h Ce, Nd,b Y Eu , Tm Cd , Tb C 1 h Zr, Hf

The thermal neutron flux in the l and 5 min irradiations is 4xl012 cm~2s~1, in the l h thermal and epithermal irradiation it is 1.2xl0h 125 3 cadmiue om"~ e th th 2d s~ n man 1I rati. 2 golr s ofo i d thermal irradiation the flux is 1013cm~2s~1.

380 SAMPL DATD EAN A FLOW Usuall samplee yth weighee customere sar th y db s into capsules provided by the Reactor Laboratory. The capsules are transported and stored in boxes of styrox. The boxes hold 90 - 100 capsules depending sizee th arrivan Laborator.e O n o th o lt samplee yth subjece sar o tt the Laboratory's book-keeping syste included routinme an th n di e flow of samples. After the analysis is completed the results are sent to the custome papea fore f th mo r n ri listing , paper tape, cassettr eo magnetic tape depending on the agreement.

ANALYSIS OF URANIUM

DNAe Th uraniuf Ao performes mi d wit automatin ha c uranium analyzer /!/ operatine .Th g principle analyzee seee th b n f ni n so rca device Th Fig . e1 . comprise ssampla e changer pneumati,a c transfer system measuremen,a t station with detector auxiliard san y electronics, a microcomputer, a weighing system and a container for the storage of the analyzed samples.

IMUOIATKM

SAMPLT OU E Process diagram. Fig. 1. Principles of the automatic uranium analyzer.

Three different analyzers of this kind have been built - one for own use and two for sale. All of them contain the acove mentioned features but they differ in technical details. The measurement station comprises a moderator of paraffin or polyethylene in whicn

6-1detectore r H o BF 2 imbeddee sar circulaa n i d r configuration 3

aroun3 sample dth e position moderatoe .Th surroundes ri sheea y f db to cadmium and borated paraffin.

381 The system works in the following way. The samples are loaded into the sample changer. The first sample is a blank, the next a standard and the following samples with blanks and controls according to need. The analyzer irradiates and measures the samples automatically and shoots them intwaste oth e container samplee .Th alse sar o weighed automatically computee .Th r calculate elementae sth l concentrations and prints the results on paper and paper tape or cassette depending on the model.

ACTIVATION ANALYSIS BASED ON LONG-LIVED NUCLIDES

Irradiation of the samples are performed manually according to the scheme in Table 1. After a sufficient decay the samples are measured wit automatin ha c y-spectromete . Fig8/ , .show2 r/7 structure sth e of the spectrometer. It comprises

sample changer detector with auxiliary - multichannel analyzer microcomputer input/output devices

DETECTOR

SYSTEM OPERATIONAL DIAGRAM

Fig . Principle2 . automatie th f so c y-spectrometer.

382 sample0 12 Sampld san ehav0 8 changer e, bee66 r nsfo built. 0.5 - 5 ml capsules can be inserted in cups which are moved in a path by a rotating motor. A push and pull motor moves the sample in front of the detector. A lead shield 20 cm thick shields the detector from the background radiation. Shields for detectors used for measuring low-energy radiatio linee nar d with cadmiu e copperd th m an l Al . movements of the changers are controlled by the computer so as to reach maximum flexibility. The detector to sample distance can be adjusted manually.

Ge(Li)-detector relativ% 5 s2 wit- e0 h1 efficienc witd yan h energy usede EYJHV e ar r 133 ke On .fo V M 1 2ke resolution 2. - 7 1. f so low-energy photon detector with dimensions of 5 x 010 nm and an energy resolution of 600 eV at 122 keV is also used. As spectroscopy amplifiers onlCanberre yth a models 202 usede 1ar .

The multichannel analyzers includ Nokie eon a LP4900 Canberre ,on a analyzere th Canberro l 8100tw Al Canberre s d on , . hav an a35 0 ea4 4000 channel memories.

The central board of AIM 65 by Rockwell is used as basis for the computer. Memory extensions, the power unit, the case and inter- faces are made at the Reactor Laboratory. The computer has 8 bit word length and 40 kbytes of memory. The main programming language is Basic. The standard Basic is extended by about 50 new conmands. additionae Th l command meane sar tcontroe e mainlth th r f lyo fo analyzer, sample changer and I/O devices. For manual control the standard keyboard of AIM 65 is used. Other I/O devices are an E^json MX-80/RS232C printer with 2400 baud. An MFE 2500 digital cassette terminal (2400 baud alss )i o program controllabl Basif o t cse a y eb commands. Thi principalls si n outpuca e yth s i usedat f r tt o fo dabu inpue als th dat f useprogramste o d r ob aan fo d RiilipA . s NE2235 audio recorder (600 baud) whic manualls hi y controlle routinn i s di e use for the input of programs and data.

The system function followss sa : Each sampl measures ei givea r nfo d time after whic spectrume hth , also containin life-time gth e th f eo measurement transferres ,i d intmemorocrnputere e oth th f yo e Th . computer also register measuremente timed th en stare f so sd th tan .

383 Then the measurement of the next sample is started immediately. Daring the measurement of a sample the computer deals with the analysis of the spectrun fron the previous measurement. Because the measurement tim program-controlleds ei samplee th seriea l n si ,al s can have different mesurement times.

The input data are partly stored in the computer memory and partly cassetten o cassettee Th . preparee sar d beforehand usin separatga e "editor" compute same spectrometerse th e th uses f ri kino n i ds da .

The data is loaded into the computer memory when a measurement is started. First the spectrum is analyzed. The peaks are looked for, and when found the energy, area and statistical errors among other datcalculatee aar printed dan papern do . Afte spectrue rth bees nha n dealt with, the quantitative calculations will be performed. If desired firse ,th t samplblanke b resulte n ,eth ca whicf so e har subtracted automatically from the rest. In most cases no bland is needed. Then the first samples are standards, of which any number used e calibratiob e Th n . ca n coefficient computee sar d frodate mth a of the standards. Using these the elemental concentrations of the samples are calculated after correction for dead time, decay, sample weigh neutrod tan n flux neutroe Th . automaticallne b flun xca y accounte insertiny b r dfo g flux monitor seriese peath o n f n ko sf i . I a predetermined energy is found in the spectrum, the program will calculate an upper limit for the corresponding element.

The elemental concentrations are printed on paper and if desired also on a digital cassette. This can be used for the transfer of data to another compute datr rfo a processing usee th d f doeI hav.t sno e a cassette terminal, the data is transferred from the cassette to computer compatible magnetic tape using the facilities of the computer Technicacentre th t ea l Research Centre.

FURTHER DEVELOPMENT

degree Th automatiof eo currentls ni y increase differeno tw n di t ways. Firstly completel,a y automatic activation analyze shortr rfo - lived nuclides is being built. Secondly, a centralized data collectin plannine g th systen i gs mi stage firse .Th t devic aimes ei d at being working at the end of 1985 and the second at the end of 1986.

384 The principles of the automatic activation analyzer is shown in compriset I Fig . .3 samplsa e changer pneumati,a c transfer system,a balance ,y-spectrometea nacroconputera d ran systee .Th m will automatically analyze a series of samples, weigh them and give as output the elemental concentrations. It can be used for normal short- lived nuclide activation analysis, cyclic activation analysis and delayed activation analysis .seriea Tha, samplef tis e so b n sca irradiated, stored in the sample changer and measured separately afte suitablra e decay time.

SAMPLE OAT- - *--

Fig . automatiScheme .3 th f eo c activation analyzer. maie th n f drawback-spectrometero y e e On th f so s presently uses i d that the spectra cannot be stored. Thus most failures during measure- ments, errors in the data and so on compel all the samples to be measured again. Likewise the use of cassettes to communicate data is unsatisfactory. Therefore a centralized data storage and computing system is going to be built. The principles are shown in Fig. 4. All the separate analyzers will be connected to a IBM PC/AT. The AT will have a central memory of 3 MByte, a floppy disk of 1.2 MByte and a hard disk of 20 MByte. It will automatically collect all the spectra, stor haree th thed n diskmo , analyz ye -spectreth d aan

385 AUTOMATIC Y-SPECTROMETER

Fig. 4. Scheme of the centralized data collection system.

calculat elementae eth l concentrations casn .I errorf eo spectre sth a can be reanalyzed and all the errors corrected. The AT will be connected to the VAX 11 of the Technical Research Centre for the production of magnetic tapes and for direct communication with customers' computers.

REFERENCES

1 R.J. Rosenberg Pitkanen. ,V Sorsa. ,A automatin ,A c uranium analyser base delayen do d neutron counting Radioanal. J . . Chem (1977) _ 179- .37 9 .,Ib

2 R.J. Rosenberg ,simplA edeterminatioe methoth r fo d f no uranium and thorium by delayed neutron counting. J. Radioanal. Chem. 62(1981) 149- 5 .,14

3 A. Bjorklund, M. Tenhola and R. Rosenberg, Regional geochemical uranium prospecting in Finland. Exploration of Uranium Ore Deposits. Proceedings of a Symposium, IAEA, Vienna 1976, p. 283.

4 R.J. Rosenberg, Instrumental neutron activation analysis as a routine method for rock analysis. Technical Research Centre of Finland, Electrical and Nuclear Technology, Publication 19, Espoo 1977.

386 5 R.J. Rosenberg Kaistil. ,M Zilliacus. R d aan , Instrumental epithermal neutron activation analysi solif so d geochemical samples. J. Radioanal. Chem. 71(1982), 419 - 428.

6 Rolf Rosenberg, Riitta Zilliacus, Maija Kaistila, Neutron activation analysi geochemicaf so l samples. Technical Research Centr Finlandf eo , Research Note 225. sNo , 1983.

Vanska. L , R.J 7 . Rosenber Pitkanen. V d gan automatin ,A c gamma spectrometer for activation analysis. Nuclear Instrument Methodd san s 213(1983) 347- 3 .,34

8 R.J. Rosenberg and L. Vanska, STCAV84, a computer program foautomatin ra c ganma spectrometer useactivatior fo d n analysis. Technical Research Centr Finlandf eo , Research Report 415. sNo , Espoo 1985.

387 APPLIED RESEARCH PERFORMED AND IN PROGRES USINY SB GTRIGA A NUCLEAR REACTOR

. MOAUROA . MADARM , O ENEA-CRE Casaccia, Rome, Italy

Abstract

e TRIGTh A reacto f ENEo r A Casacci s beeha a n use n differeni d t applied research fields among which particularl e followinth y g applications of neutron activation analysis (NAA) are reported: ) Environmentaa l The result e referree determinatioar sth o t d f abouo n 0 microele3 t - ment n i marins e suspended particulate matte d sedimentsan r A stud. y s alswa o performe e impuritieth e n filtero dth f o ss user environmentafo d l studies and an intercompanson was carried out on two sediments distributed by the Joint Research Center, Ispra, Euratom. Forensi) b c Many applications of NAA have been performed in this field on request of Italian Courts for determination of gunshot residues, particularly on paraffin gloves and clothes of person suspected to have handled and'or fired a gun; also the firing distance was determined in some cases. c) Plant nutrition e uptakTh f cobalo e e toleran d zinth s beean tha d c nan - studiet po n i d ce index was established in cooperation with the Istituto di Cerealicoltura Roma. d) Geological The rare earth concentrations normalized with respect to the chondn- tic rocks can be utilized for petrogenetic studies and some determinations have been performed both by thermal and epithermal NAA on some rock samples. A program of utilization of the Triga reactor in the field of the preparation of a Ir-191m generator has been provided for applications in the pédiatrie angiography. For this purpose a cooperation with the Clinical Physiology Institut f Nationao e l Research Counci f Piso s l ha a been escaoJished.

INTRODUCTION

This n e outlina differenpapeth s i f ro e t subjects e studieth t a d Casaccia Research Center, Rome (Italy) by using neutron activation analysis (NAA i , particularly in its instrumenta] version; in some cases, for reducing interference problems, we have also performed some chemical separation on the activated products or we have used epithermal neutron activation analysis. The irradiation facility used for neutron activation purposes is a TRIGA reactor that is operating in the Casaccia Center since 1960, whos es raisewa initia n 196W i K do 1MWt 7 l0 10 ,powe f o r o thas e maximuth t m neutron flus enhancewa x o 2E1t d 3 neutrons/cc se m in the central hole. Most irradiations, however, are performed in the

389 rotatory rack (Lazy Susan), wher e irradiate0 b vial4 e n ca s d simultaneously t aboua t 2.5E12 n/on sec e rotator,th y movement ensures that o n ther s i e large difference in the neutron flux from a sample to another, due e.g. a clos o t e control rod. However a referenc, e materia s i frequentll y coupled to the sample to perform quantitative determinations. Short irradiations can be performed one at a time in the pneumatic device (rabbit) at a flux of 1E13 n/cm sec. As regards the measurements &f e neutroth n induced radioactivity e Germaniuus e w , m detectors (Ge(L:i) or HPGe V f resolutioabouo )Ke 2 t t 133a n 3 KeV, connecte o thret d e diffe- rent multichannel analyzers; one of this is connected to a PDF 11 computer that use a softwars ee accumulatioth packag r fo e f o gammn a spectra, the identificatio f nuclideo n e energiee ratioy meanth th (b sf d o ss an s of characteristics photopeaks and half-lives) and the quantitative analysis.

ENVIRONMENTAL

In co-operation with the ENEA Environmental Protection Department, many samples of marine suspended particulate matter (SPM) and sediments collecte n i somd e campaign n Centrai s l Tyrrhenia a (ItalySe n ; frig. 1) were analyze e determinatioth y r INAb d fo A f mano n y trace elements (1.2). The SPM samples were collected by filtering through 0.22 urn Millipo- S membranerG e s aliquot 2 liter f o f smarino s e water take t differena n t water column depths (from 7.5 to 100 m) at surface level and at the bottom. The filtration was performed under inert gas pressure ( 0. ^ atm l and, afte a washinr g step (tha d Br) an te filter ,th l removeC , sNa s were pelletized to obtain a good geometry during the irradiation ana

50'

Fig. 1. Study area

390 C" . > amountov rtin1 f o ge soms th stepe aus r B , o elerrerF es o 1 1 +s i pr i >uev s dp-^er e impuritieth re filterf inatth r o bees a i n ~ i ha sr p rte re n TaMi d e ar 1 e s t 1 i e r " h t , ^ "he se liment^ v\err collected b> a f re^-f al 11 ng perspex COT ei 'i forent depths ( fri^rr 1C to ICi" rr ) The saTij les v^ere h~rroF»= ir <= jiie , d r proun1 a beforagatan ^i "i n i ^de 1 p<= 1 ] 1 etizatio b i Fo n

d ^ennents^i , tvic irradiation rendition a sho' c fj^^es * u t i^ri t n i

3 0 °^conds) foi the dc ^erni nat i on of Mr and a long one f 3(. h^t ° f' i 1 f 1 - f l n t s I /1^ "taniard1 refe^err«" materials '-"chare leaves NFc-ql" ar1 lale S^iinei °i-i j HI ^ v irraiidted along i^itt he sin[ r 4 r

' i qi ant i tative dotermnation^ ani for accurarv evaluation

v fhp resjlts obtained for SPM are reported in Table c ar d rr r it r c r t in Tatle ^ In urfemrnt v, t h ott -' îjthor^ I 4 j , vs<= ha e r th enrirhicn fac! r f i eve (lernen*, A j h ifspe 1 t ^ hf 1 i i il t i '

Table 1 Total amount» trate th f i o ,elimerit t filterIh n si i (ng)

i Icrnents Numbef o r Mean Sld dtv cv % sample-s valut

Au 10 0 20 0 P 60 Ce 5 10 4 •) "i 11 ( 0 10 8 8 0 2 23 Cr 9 335 67 2 20 L 1 10 4100 1800 45 U 10 26 2 1 48 Mn 10 247 58 24 Sb 9 10 6 4 2 40 Sc 9 0 39 0 25 64 Sm 3 0 27 0 18 67

Table l t lemc-it concentrations in se aM (Vi1 SP */jg/lg )

s t n e m 1c T Surfai L samples Bottom sarnplf s n ra "*f n lange

A^ 14 4 < 59 12 25 150 Au 2 3 0 1 3 0 U* 4 14 65 3 47 78 (e 32 7 4 136 33 12 164 Co 32 4 3 158 30 4 6 59 Cr' 3 0 1 1 2 3 0 3 0 4 C5 14 0 59 21 16 8 1 25 1-c« 36 3 8 41 34 58 55 H r 4 3 074 6 0 1 3 7 HK 2 4 2-5 5 5 13 17 ij 27 7 8 62 25 95 124 u I 2 0 3 1 1 2 0 22 0 1 Mn« 27 0 12 21 35 0 2 35 Sb 12 9 1 179 12 7 8 42 Sc 42 0 696 36 l 2 18 Sc 2 6 7 10 2 4 7 7 8 Sm 35 0 4 91 25 3 1 60 la 14 I 5-26 B 1 5 35 Th 32 1 1 28 34 2 9 39 V, 11 47 858 11 19 1346 Yb 9 1 1 51 7 1 1 11

391 TABL Concentration- 3 E sedimente th n i s Gulf so Gaetf fo a (ppm)

Elements Mean Value Standard déviations C<> 146 11 Co 14 0.5 Cr 83 3.8 Cs 12 0.7 Eu 1.2 0.005 Fe 37000 1500 Gd 15 0.8 Hf 5 0.2 Mn 740 49 Rb 154 14 Sb 0.16 0.01 Se 12 0.4 Ta 1.7 0.1 Tb 1 0.08 Th 19 1 Yb 4 0.2 Zn 105 11 Zr 292 23

EF = (X/Sc) SPM

X (X/Sc) crust

Scandiu s beeha mn e selectereferencth s a d e element, b-caust i e is representativ e alumino-silicateth f o e e terrestriath n i s l crust and, owing to its low solubility, is little affected by pollution. The pattern of the EF-values is reported in Fig. 2, where EF-values for

Au

• Sb

Cs TQO o

Yt> LG o Co, o Lu r5m o Ht o . . Th! Ce 0 0

Mn\Fe/Co

Alomic number trenF . atomiE . Fidvs 2 g c number - thi f n . s workRc - v ;

392 oceanic water e alsar s o reportes i interestin t i d o t observg e that thes t substantiallo curveno tw ee ar s y different although thee relevanar y t o vert y different environments. e higheTh e EFx-valueth r e highe th ,e effectivenes th ro t M SP f o s a scavenge s a t ac r with a water respecte elemense th n i .o t x EF-valuet s close to unity are found for Fe, Vn, Co and Th, while Zn, As, Se, Sb, u have highesA th ed an tW values, Hg .E sho CesiuRE a wclea d an mr deviation e frogenerath m l trend see o an fort d m a separatm e group. This fact is interesting because some REE may simulate the environmental behaviour f somo e transuranic elements because similaritth f o e f somo y e physico-che- mical constants. As regards the sediments, some elements (Ce, Co, Cs, Eu, La, Sm, etc.) can be used to predict on a experimental basis the environmental behaviou f o fissior n products from nuclear power plants and frorr fall-out. The accuracy and the precision of the method have been tested by an intercompanson analysis performed on lake and river sediments supplied by the Joint Research Center, Ispra (Italy) (5). The results are summarized in Fig. 3 and Fig. 4.

<* ?50

o TOO

150

too

50

J___L I I III III AI -is Br Co Cr Fe K Mn Na N. Sb U Zn

Fig 3 Analysis of r^er sediment S1 ; o our values, • values of other laboratories, reference values = 1OO

e t 485 r KO c 3 o X» 2

750

700

150-

• • • O

50

_L _L _L _L _L _L n 2 U b S i N a N n M K e F r C o C r B AI s i Fig 4 Analysis of late sediment S2; o our values, • values of other laboratories, reference vaJues = 100

393 FORENSIC

It is well known that NAA has a large application in the forensic field, particularly in 01 >er to research Ba and Sb coming from primers f firearmo s cartridge o establist r o s e proveniercth h f somo e e materials, b> conpanng the activation gamma-ray spectra of the sanple^ and of a reference r aterial. We have actually been requested for expert witnesses by many Italia ne determinatio th Court r fo s f gunshoo n t residues (GSRi on paraffin casts taken from persons suspecte f havino d g used fireans ir criminal circumstances. A co-operation with Police National Laboratories f Rono s beeha e r activatA courseNA d san e were hel o technicat d l peor1e from these laboratories, performing fire test n differeni s t exper j.men^a-. condition d comparinan s e resulte DT~dffith th g f o s r test, many different "occupational blanks" have also beer performede ar n .e q Usuall== 0 1 y taken from tipical regions (back of the ^hjmb and of index) ana activ^t^d for an hour in the pneumatic device. Bd- 13e» after IOC min. and Sb-129 after t^o days are measured From this exoer irrental work (6) it wa=: conca j td that - usefu1 l informatio e l uDidine r r r ^a panffir nf ' n cast<=- only nher e thepreparear y t lonno d g n easi ra afte e fi lP p C th m iractG s a , disappear after washing or rubbinp the hards, e case th n mosi f s o - t onle antimon2 e th detectedyb e bariun th ca y s ma , is frequently overlapped by the sodium and chlorine interferences, i ns considere i thi b S s f occurenco a dthresholg u 1 n amouna e0. df o t for "GSR consistent values".

e paraffiTh - 3 n e considerecasb o tt tess ha td unreliabl n mani e y cases because of the different techniques used in its preparation, e.g. frequently a large quantity of gauze is employed and the sampling operatio s impossiblei n . 4 - It was suggested that a good alternative could be the swabbing method used by Rudzitis (7). The clothee th a persodistributio n f o o s nR GS reache a f o ny b d gunshot has been found useful for the determination of the firing distance by comparing with analogous distributions obtaine t differena d t distances in tests performed with the same firearm and cartridge of the crime. This determination was found useful in many cases. In this fiel f provenienco d e studie f materialo s y meansb f activatao s - ble trace elements a researc, s performe wa n hlipsticko ) (8 d f differeno s t brands in order to compare lipstick residues on glasses, paper, cigarettes, etc. e elementTh . s , use theiI s a fingerprint d, rBa , Br , l sA wer, Ti e ratios showed useful evidence in many cases.

Plant nutrition e effectTh n f i increasino s d C d an g u C concentration , Co , Zn f o s the soil on the early growth of four important cereals (maize, barley, durum and bread wheat) have been studied, because these elements are frequently found in irrigation waters coming from highly populated and/or industrial areas. Particularly the inadequate growth and the increase e e tissuemetalth th n f f i theso o ss e cereals have been investigated.

394 For this purpose, a non-destructive method of analysis has been required to analyze so many samples to obtain statistical significance. 6 sample21 s have been analyze y INAb d A (9), whil r cadmiufo e d an m cop-j^ a radiochemicar l separatio s beeha n n neede o d resulttw an d r fo s rybnd f maiz o se presente ar e d here e raoiochemicaTh . l separation schene is r-,jorte n Figi d. 5 .

. 3 RADIOCHEMICAL SEPARATION SCHEME

SAMPLE (Digestion solutio HNOn d H_0ni an ,„

RESIDUE JDissolvc1 HC N 8 n i d

SOLUTION 1AP column extraction

HAP EFFLUENT 24Na Passed throug columa h Dowe8 f no x x1

RESIN ELUATE

B , ns-in, 59Fef

51 86 46 ul| £flf Gâ Cr, Rb, Sc

In table 4 the means of the results for Co and Zn respectively are reported, in the first column there are the concentrations (in ppn i found in the plant tissues, in the second column the ratio C between tne concentratio e sampli th i e e blank ^ third th n th thai l an n en co n i di t, e tolerancth e ratith e s oa inde betweei t e xsample weighth th n f o et and that of the blank. The strict correlation between C and ti is well visualized in Fig. 6 and 7; the same trend ha^ been found for Cu and Cd for two maize hybrids (table 5). The same correlation a evident also by examining other parameters considered in our trials. Iherefore, it is allowed to affirn that the use of the index T is highly i nd i <~-, ' i .. f for thf1 nutritional conditions of t HP 1it,-,i.es, ird permit' t - cit. ' r ' l rieneni < a h Ii' statu<- c f- t1 > l o f so sdeficienc s es x f r ^ y

395 U) VO ON (ppmn e Z ti«su«o th d Tabl n ) an i - Valueo 4 eC , f »nro s t respective t indexa d an C s

MAIZE BAULKY DimUM WHEAT BREAD WHEAT Concentra- e th tio n ni

soil (ppm pptn C t1 PI« C t t C ppm ppm C t added) ————————————— —————. —.

22 0 2.6 3.5 1.? 1.9 25 164.5 65.3 0.79 125.7 57.3 O.b71.i5 63.9 0.7 B . 30 50.760.8 6 50 271.2 10M.7 0.70 265.9 139.4 0.7? iié.P 102.7 0.67114.9 61.9 0.69 100 502.0 201.4 0.6? Î52.4 159.5 0.6i 276.5 216.6 0.5,120Ö.2 102.9 0.46

I.. S.D. (P.O) .05 60.1 37.5 0.1? 90.9 99.2 0.17 57.8 88.0 O.O42.R9 58.0 0.07 (P=0.01) 83.1 53.3 0.11427. 0 150.3 0.279-69 125.2 0.1159-3 62.5 0.11 —————-- —— ..-....„._..._„_...„„. In 0 22.3 59.9 21.5 74.0 c ,o 293.3 14.5 '.02 419.6 6.9 i.O 3 8. ?0.9169.9 9 263.9 4.0 1.03 100 i . 0.^510.20 2 4 778.4 12.6 1.05319.3 13.7 0.92440. 0 7.6 0.95 200 1239. U 73.0 0.961275.7 20.9 0.9 y 9 71 469.0.80 9 664.2 13.0 0.87 400 2864.3 U7.7 0.892424.0 40.9 0.66KC8.0 62.9 0.61163.08 20.1 0.69 L.S.D. (P.O. 05) 196.0 26.2 0.09 407.4 9.1 0.12 21? 4 . 12.7 0.1 53 8. 235.0.06 7 (P.O. 01} ?67.4 36.2 0.1571.32 13.1 0.1209.77 17.6 0.20321.3 12.1 0.10 MAIZE n »o« d e X e '»o s

SO 100 ppm m pp too

l DURUM WHEAT BREAD WHEAT n 1)0 n d e ed x x e 10° 10 s

100

10

OJ ot

so too ppm o m topp o

Fig. 6 - C and t. values against Co concentration in the soil.

397 MAIZE „no d e

O IO O S 0 too oto o t o m «0pp 0 100 «oo pprn

DURUM WHEAT BREAD WHEAT n n d d e e x x e e s s

OS

O IO O S 0 too o to 40 o 0s ppr o n too value. t d an s C agains Fig- .7 n concentratio Z t e th n ni soil.

398 - 5 Value a/iu e tissue C hybrideo (pp'nd th - dC tw of cn i f ) o s s f mai^eo .

^^^^HYDKIDES OeKalX LU b FUN . 444G K 9 j TREATMENT (p^ro"--^^ 1e soil)^"^\ddriafth o t i ^

C_u_ 0 23.68 35-6? 25 50.43 56.09 50 88.91 98.89 100 165.31 139.72

C_d o 0.26 0.23 25 19-13 7.04 50 23.18 8.34 100 60. ?3 21.69

Geological

Epitherma A (ENAANA ls beeha ) n e analysie usefufounb th o n t di l s of geological samples, in order to reduce the interferences in gamma-spe- ctra (10-12). The principle of this procedure lies in eliminating the thermal componen neutrothe of tn flux, e.g. irradiatin samplethe ga containe in s r made fro a materiam l havin a higg h thermal cross-section, sucs a h cadmium or boron. In this way, the neutrons used for the irradiations are only those having energies than a threshold value, depending on the particular material e activitieTh . o s obtaines e generallar d y lowerede activatioth t bu , n ratios among different nuclide e changear s d in such a way that some elements of geochemical interest are determined better thay TNAAb ne highesTh . t improvement e obtaineb n ca s d for. Ga-72, As-76, Se-75, Br-82, Rb-86, Sr-85, Ag-110m, Sb-124, Cs-134, Ba-131, Sm-153, Tb-160, Ho-166, Er-17l, Tm-170, Ta-182, W-187, Au-198, Pa-233, Np-239 e havW . e tested (13 e accuracth ) f boto y h d TNAan A ENAA using some USGS reference materials n TablI . 6 some e results e reportedar , compared some literatur e compilationth e o t value d an s s f o Flanagan (14 d Abbean ) y (15) e detectio.Th n limits evaluatey b d the Cume's method (16) for TNAA and ENAA are reported in Table 7, along with their rations (improvement factors).

399 TABL Concentration- USGo E6 tw S n geologicai m pp n i s l standards, (n.d. «= not determined)

aSP-l (granodiorlte)

TNAA ENAA rang f o e Flanagan Abbey llterutura value

Bu IZ/b 1340 1100-1300 1300 1300 Ce 404. «i 400 360-508 394 360 Co 7.0 7.6 6.4-7.8 6.4 7.8 Cs I.-' 1 .05 0.0-1 .25 1.0 1 En 2.3 2.55 2.N-3.1 2.4 2.4 La lb/ n.d. 161-195 191 195 Rb 264 ?D<3 POO-298 254 250 ' :. . J Sb J.7 J. 1-4.1 3.1 3.1 Sc 6.6 7.6 6.0-7.2 7.1 6.6 Sm 27.7 n.d. 23-28 27.1 25 Sr JÜÜ 23-1 195-240 2J3 240 Ta 1,25 7 1 , 1 O.U-1.4 1.0 1 Tb 1.1 1 ,5G 1. 1-2.0 1.3 1.4 Th 115 lOb 101-128 104 105 Yb 1..' n.d. 0.9-1.2 1.8 i.9

BHVO- 1 (BASALT)

TNAA ENAA rangf o e Abbey literature value

Bu n.d. 159 I2D-20B 130 3 . , Jt Ce 10. 1 'n-46 - Co 45.5 114. d 12-4/ 47 Cu n.d. (1.032 O.Ob8-0.15 - Eu 2.02 l.G-2.4 2 Hf 4.5 3.9 3.8-4.6 - La 14.7 15.15 14.7-17.5 - Rb n.d. 9.0 8-11 9 Sb n.d. 0.164 0.15-0.43 - Sc 36.1 35.1 29-34 - Sm 6.2 G.2 5.J-6.B - Sr J1V 136 I7S-43B - Ta 1.7 l.CS 0.9-1,3 - Tb 1.5 1. 1 0. 70-1.4 - Th 1,71 1 .55 0.82-3.2 - U n.d. 0. Jb O.JO-O.bO 0.4 Yb 2.5 1.9 1.57-2.42 —

TABL- 7 E 7 - Detection limits und Improvement factorm pp n i sr BHV1 fo - O

LD LD Improvement TNAA ENAA factors

Ba 250 42 6 Ce 1 5 0.2 Co 0.33 0.9 0.37 Ca 0.5 0.05 10 EU 0.1 1.0 0.1 HI O.J 0.5 O.b L» o..) 5 . 1 0,2 Hb ..'u 4 5 Sb 0.8 0.1 8 Sc 0.06 0.37 0.16 Sm 0,07 0.1 0.7 Sr 120 So 2.4 Ta I . 0 0.08 3.75 Tb o.;' 0.1 2 Th 0.1B 0.16 1,1 U 2 0.1 20 Yb 0.(> 0.5 1.2

400 The distribution and the fractionation of rare earth elements e rockth n giv(REEca n si e ) significant petrogenetic information. The main parameters of importance are: the degree of fractionation e occurencth d an eE RE ) ) relativLu Eu o o t t f o lighheavo t ea d (L (G ty of Eu anomalies. Rock samples from Kenya were analyzed by ENAA. figure 8 shows the chondritic ratios for REE in the different types of basaltic e seeb n rocks ca tha e e u enrichmentt anomalE I th tar . d E an RE y f o s different from a rock type to another.

1OO

10- La Ce u E m S

—————— Basanite

x----- Alkali basalt

— Transitiona. _ . — l basalt Fig. 8. Chondritic ratios. -* — x — «pholentic basalt

Andesinic basalt

*"*"* USGS- BCR 1

401 In co-operation with Clinical Physiology Institute of National Research Council of Pisa, the problerr of radioisotope production has been studied, particularly to obtain short half-lived nuclides to be used in nuclear nedicine. A possible applicatio e preparatioth n e e Os-19b seemth o t f so 1 n generator that produces Ir-191m, whose short half-life (4,9 ) allows 6 s n pédiatrii e itus s e angiography.

REFERENCES

1) R. BONIFORTI, M. MADARO, A. MOAURO, J. Radioanal. Nucl. Chem., Articles, 84/2, 1984, 441 2) M. MADARO, A. MOAURO, R. BONIFORTI, ENEA RT/TIB in press. MOAURO. A ) 3 . MADAROM , , ENEA RT/TIB (84. )8 4) P. BUAT-MENARD, R. CHESSELET, Earth Planet. Sei. Lett., 42, 1979, 399. 5) M. MADARO, A. MOAURO, J. Radioanal. Nucl. Chem. Articles, 90/1 1985, 129. . MOAUROA ) 6 , Convegn i Balisticd o a Forense, L'Aquila, 25-28/3/1981. RUDZITIS. E ) 7 FORENSIC. J , , Sei. , I96025 , , 839. . MERLIS ) . 8 MOAUROA , . PALMAG , . CAPANNESIG ; , Arch. Kriminol., 161,. 1978, 137. . MOAUROA ) 9 . BAROCCIOA , . ROSAG , I internationaV , l Colloquiur fo m the Optimizatio f Plano n t Nutrition, Montpellier (France) 2-8/9/1984. ) A.O10 . BRUNFELT ROELANDTS. I , , Talanta , 197421 , , 513. 11) S.J. PARRY, J. Radioanal. Chem. 59, 1980, 423. 12) Z. RANDA, Radiochem. Radioanal. Lett., 24, 1976, 157. . MADAROM ) . MOAURO13 A , I Hungaro-ItaliaI , n Symposiu n Spectrochemistro m y Budapest, 10-14/6/1985, in press. F.J) 14 . FLANAGAN, Geoch. Cosmoch. Acta , 1973,37 , 1189. 15) S. ABBEY, Geostandard Newsletter, 4, 1980, 163. 16) L.A. CURRIE, Anal. Chem., 40, 1968, 586.

402 STABLF O E EUS ACTIVABLE TH E TRACERS IN ENVIRONMENTAL AND BIOLOGICAL RESEARCH

M.J. MINSKI Reactor Centre, Imperial College, Silwood Park, Ascot, Berkshire, United Kingdom

Abstract

Stable tracers have advantagth e e over radio-tracer n thai s t they cae use b nn situation i d s where radio-tracer se considere b woul t no d d acceptable. For example in biological research they can be given to children, pregnant women and volunteers with no risk of radiation and in the environment large quantities can be distributed over an exposed area e publicwit th o risn e hstablo Th t k. e tracer e analyzear s y neutrob d n activation using the Imperial College Reactor; the most suitable activable tracers are those having a large activation cross section and a short halt life for the radionuclide produced. This gives high sensitivity and enables large numbers of samples to be analyzed in a short time n certaiI . n s usefucasei t i o enricst l e stablth h e isotope and biological work here involves the use of stable enriched ^8Fe to study iron uptak n humansi e .

Current work using stable tracers at the Reactor Centre is both environmenta d biologicaan l d consist e an followinl th f o s g applications:

) Iro(1 n absorptio humann i n s ) Dysprosiu(2 a stabl s a m e e traceenvironmenth n i r t ) Stabl(3 e tracer o investigatt s e uptak f radionuclideo e s released from nuclear power plants

Introduction

Stable tracers have the advantage over radio-tracers in that they can be used in situations where radio-tracers would not be considered acceptable r examplFo . n biologicai e l researc e givehb theo n t nca y children, pregnant wome d humaan n n volunteers wit o risn hf radiatioo k d an n in the environment large quantities can be distributed over an exposed area with no risk to the public.

To assess the capabilities of a stable tracer certain criteria mus e satisfiedb t , these are:-

1 . The stable tracer must be capable of activation by neutrons to produce a radionuclide.

2. It should have a large activation cross section to give the maximum sensitivity.

t shoulI 3. d produc a radionuclide e wit a shorh t half lifo t e minimise the irradiation time and also to allow a large number of samples to be analysed in a short time which is of particular importanc n biologicai e d environmentaan l l research.

403 4. It may be necessary to use an enriched stable tracer where the natural abundance of the tracer is too low to give reasonable sensitivity after activation, e.g. "Fe has a natural abundance of r greate o e enriche b % o n 66 increast r ca o t dt Q.3% e bu th e sensitivity of measurement.

5. In the environment it is an advantage to use a stable tracer which is not commonly found in it, e.g. l'*Dy.

Other points to consider when selecting a suitable stable tracer are that the tracer can be suitably incorporated into the system under investigation; that the material incorporating the tracer does not produce n unnecessarila y high backgroun o irradiatiot e du d f otheo n r elements present in the system and that the Y ray (or rays) produced by the stable t interferetraceno e ar r d wit y otheb h r activation products.

Experimental techniques

Imperial College has a 100 kW CONSORT reactor of the pool type being moderated, reflected, cooled and partially shielded by light water. It contains a variety of facilities for irradiation of samples of which the followin mose ar gt usefu r activatiofo l f stablo n e tracers:-

1. Cor reactoe o faceth tubestw f so n rO :cor e 8 verticather e ar e l tube r irradiatiofo s f sampleo n standarn i s d polythene capsuler o s aluminium isotope cans, one of these is cadmium clad to enable epithermal neutron irradiation e carrieb o t s d out e therma.Th l flux ranges from 0.63 x 101 * - 1.20 x 101Z n.cm~îs~l depending upon the position in the tube. These tubes are suitable for irradiations lastin o severat g y froda l1 m week d thereforsan r fo e tracers producing radionuclides with long half lives ( ^ days * years).

2. In Core Irradiation facility (ICIS): This is a pneumatically operated system providing fast transfer of samples from reactor to detector or to the radiochemical laboratory within approximately 10 seconds e systeTh . s e corlocate e centri d mth th an e f n o ei d has a thermal flux of 2.27 x 1012 n.cm~2s~1. This enables irradiation of tracers producing radionuclides with half lives from minutes to hours.

. 3 Cyclic Activation System (CAS): This i anothes r pneumatic transfer system situated near the centre of the core but allowing transfe f sampleo r s from reacto a countin o t r g system situated neae reactoth r r withi 1 seconds0. n e systeTh . m consisto tw f o s irradiation e aluminiutubee otheon th - s rd an cadmium m clao t d allow epithermal irradiations e systeTh .s automate i mn ca d an d accommodat 0 sample3 e a tim t a es wit a choich U mode f f o eo s operation to enable single or multiple irradiations to be carried out in a cyclic or cumulative manner. This system can be used for production of radionuclides with half lives of seconds + minutes and is the one best suited for the stable tracer technique. The thermal flux for this facility is 1.20 x 101* n.cnffs~l.

y spectrometrra Y f irradiateo y d sample s performei s d usina g Nuclear Data system which enable 8 sdetector e connecteb e o t son o t d computer controlled multichannel analyser capabl f carryino e t peaou gk search measurements followed by concentration measurements using suitable standards. Ge and Ge(Li) high resolution semi-conductor detectors enable determinatio d higan hf botw o n energ y lo photopeaksh ra t y .

404 Application of stable tracer techniques

Stable tracers have been used since 1968 when bromin s bromid(a e e s use o wa stud t ionde movemen ) th y f wateo t r within waterflow systemd an s the movement of surface and subsurface waters (1). The method is sensitive down to tens of parts per billion level. Bromide has several advantages when used as a tracer in water systems, namely, the bromide ion remains with the groundwater to which it is added; it is non toxic even in high concentrations in drinking water, it produces "Br (y 617 keV) with a half lif f 17.7o e d crosan m s sectio e trace 5 th barn 8. d n ran s itsels i f inexpensive, commercial grade ammonium bromide being suitable n examplA . e s thai te us give s y D.Cb it n ) f wher. o (2 e trace Raupacth . es al wa r t e h use o identift d n acia y d mine drainage s thoughsourcewa t I t. that acid mine drainage water was flowing into a stream and by adding 50 Ib ammonium bromide at the suspected water source, collecting samples for one month at the outlet porta d plottinan l a broming e breakthroughs curvwa t i e confirme source d th tha min e f contaminations o eth t wa e .

The earliest use of stable tracers in the biological field was as a trace r digestiofo r n studies. Early worker d show e suitabilitha s th n f o y radioactive n indea Cerium( r digestibilits fo a x ) lCe ** y s sincwa t i e s rapidlabsorbe wa f ruminant o t a smal bu t yo t gu d) l e (3 sextenth y b t absorbed into and remained bound to digesta particles (4), however, since it was radioactive waste disposal was a problem hence stable cerium was used instead (5). Samples were irradiated for 20 minutes at a flux of ^ x 10l> n.cm~*s~'e ,C allowe* * ' 7 daydecao s d countet da r min2 an s fo .yr fo d (y 1U5 keV, Ti 32.5d, a 0.6 barns) and the digestibility of feed determine y measurinb d g e feeceriud faecesth an d n i m .

By the 1970's stable tracer techniques had spread to studies on humans, in particular for absorption and utilisation of different elements from the diet under different conditions. In 1972 Barltrop et al. (6) and ) studie(7 . al dDye t utilisatioe r y neonateb a C d irof d chromiuan so n an n m by pregnant women respectively. Stable calcium enriche n *'Ci d n safelaca y be administered to babies and was incorporated into a single standard feed. By sampling blood, urine and faeces the absorption and retention of calcium b a babyd cow' fe y s milk coul e estimatedb d . Carmin a non-absorbabl( e e marker) was given with the feed to mark the beginning and end of the faecal collection period. There are two calcium isotopes that could be used for this experiment:-

3 y barn1296.»*Ca(n,y)*0. V = s= 1.7ke 9 a i dT 7Ca V y 308barn1 ke *'Ca(n,y)"C1. 3 s= = 8.8o j mT a

The "*Ca has a natural abundance of 0.0033$ and was enriched to 3-5$ *'Ca whereas **Ca has a natural abundance of 0.185$ and can be enriched to 100$. However more 100$ enriched *'Ca is required than 3.5$ enriched **C o give samt a th ee respons e d 100sinc th an e cos $th f eo t **Ca was greater than 3-5$ *'Ca the latter was selected. Iron deficiency is one of the most widespread and serious of dietary problems; use of stable, enriched **Fe enables determination of the iron status of a pregnant woman without damage to the foetus. The parameters of interest are iron absorption, red blood cell incorporation, maternal-foetal transport and blood volume. The latter is measured using stable enriched **Cr. The relevant parameters are given below:-

»•Fe(n,y)*»Fe Ti = H5.1d o = 1.1 barns y 1099.2 keV V i8ke Cr(n,y)= 17. = 27.8a 0 032 i d T barnsly Crs

405 The natural abundance f thes o so tracertw e e 0.314 ar sd $an d *°Can r e F respectivel ' * r e enrichefo b d thes n an y 60-96$ca o et d . Since iron and chromium occur in blood normally it is necessary to make a correction for this amount by measuring levels before administration of the tracer. Since both radionuclides produced by activation have similar half lives the two measurements can be made using the same irradiation and counting conditions.

Magnesium is another element of importance in nutrition and children can suffer from a disease known as hypomagnesemia where magnesium is not efficiently absorbed. In order to study this the use of the stable tracer *'Mg was investigated (8). *'Mg only partially meets the criteria for an ideal stable tracer since its natural abundance is relatively high (11.24$), however, 2*MgO is available enriched to 99.5$. It also has the disadvantag a relativel f o e w croslo y s section (0.027 barns) e relevanTh . t parameters are:-

"Mg(n,Y)17Mg Tj = 9.45m a = 0.027 barns Y 844, 1014.1 keV

Because of the low sensitivity of measurement and interference from other elements commonly found in biological material (e.g. Mn, Al, Na) it was necessary to perform a chemical separation before Y spectrometry. Preliminary experiments performe n rato d s showed that *'Mg coule b d measure n urinei d , faece r bloodo s .

The author of this paper has collaborated with Great Ormond Street Children's Hospita o investigatt l f thio e s us etrace a chil n o rd suffering from hyporaagnesemia and has found that with the improved resolution of Ge(Li) detectors and improved efficiency 16Mg could be measured in biological material without chemical separation and since Mg is present in mg amounts in the body a sufficiently large amount of tracer can be administered initially to give a reasonable sensitivity. The biggest difficult is to obtain the enriched stable isotope in a pure enough form to be acceptable for administration to a human.

Turning from nutrition studies to the environment 1976 saw the extension of the use of rare earth elements from cerium to indium (9). Indiua muc s hha mhighe r activation cross section than s ceriui d an m therefore capabl f muco e h greater sensitivity, whic s veri h y importann i t d watean r r ai systems where large dilution factor e founda stablar sf I .e tracea cros s s separatesha ri 0 barn sectio10 d an ^ s f do n samplL fro1 a m e prio o activatiot r o saturatiot n a flu f t 10o a xn ls ncnT^s"1 then this permits dilution of 100g tracer to a volume of 10Ilm' provided that an induced radioactivity of 1 nCi can be measured. Il5In has these required propertie- s:

1ls!n(n,Y)ll(m T. = 54.5m a = 160 barns Y 417, 1293.4 keV It also has the advantage of low concentrations in most natural systems but has a natural abundance of 95.7$. Johansen et al. used indium as a tracer for air and water pollution. In each case the indium was separated from IL water prio o activatiot r y meanb n f coprecipitatioo s n ferrii n c hydroxide which removes more than 99.5$ of indium. Separation of the indium as well as concentrating it also reduces interference from other elements which would give high activitie a watern se activatioo s n i . l C nd an e.g a N . After activatio e ferrith f co n hydroxide precipitats i e induce n th eI 4 ll d separated by solvent extraction and subsequently measured by Y spec- trometry n throug ru 0 sample6 whole e b .th hn e ca sprocedur e weekon n .i e

406 e 1980' markea Th w f stablo sa s d e increaseus e e tracerth n i n di s nutrition studies with an extension of the range of isotopes to include "Fe, "Fe, "Zn, "Zn, 7*Se, 7«Se, «»Se, l'°Ce, '"Dy, »§Ca, "Ca with measurements in human faeces, urine, blood plasma and red cells (10). In most of the literature cited chemical separations have been used before or after activatio o removt n e interferinth e . Mn g d elementan l C , s Na suc s a h The major research in the nutrition field has been using iron and in particular 58 Fe even though this isotope is not an ideal stable tracer a lon s g sinc ha w activatiohal t lo i e f a lifd an en cross section. Some- times it is useful to use two tracers in one system arid therefore the use s beeha n studiede o"F f parameterse Th . r thifo s iron isotope are:-

5*Fe(n,Y) 9 barn = 2.62. 55= s F y T o e Nat. abund. 5.84 X ray*s 5JMn & 6.59ke 9 5. V î

Decay of S5Fe is by electron capture and emission of 5SMn X rays which means that measurements must be made using a Si(Li) detector and specially prepared thin sample r maximufo s m sensitivity.

The most common method of determining iron absorption is by faecal monitoring using a nonabsorbable marker to ensure complete faecal collectio a suitabl d an n e amoun f stablo t e trace re die o th addet t o t d produce measurable amounte faecesth n i s. Absorptio e orallth f yo n administere e labe"F d gives i l y b n

- A j ( + 0 .00322 F = A0,"Fe A F Fe

Y"Fe

where orae Ae th O»*'l F s " dosi Ff e o e conten"F e n faeceth i t s i sA_"_ F Fe A ,„ is the total iron content in faeces

o determinT F accuratele y this requires determinatio f *'Fo n d totaean l iron in faeces, however a correction factor can be applied by determining e thpresen"F e n faecei t s before administratio e labelth f .o n This method s beeha n applie o absorptiot d f iro o nn youn i nn (11 me gd extende an ) o t d absorptio f zino n c (12) followin y n intakproteia gso f o e n diet (13). e accuracTh f traco y e element bioavailability measurements a s determined by faecal monitoring is limited by several parameters: measurement accurac d precisio an ymethoe th f do n user analysisfo d , degree f isotopio c enrichment used, natural abundanc e isotopth f e o ee th used an d fractional elemental absorption occurring .e use b o illustrat t Zindn ca c e these points since there are three stable isotopes that can be used:-

"Zn(n,Y)"Zn Ti = 243.8d Nat. Abund. 148.9* o = 0.46 barns Y 1115.5 keV "Zn(n,Y)" = 13.8 mÏ ZT n h Nat. Abund. 1 18.6barn0. = Y 438.sa * V 6ke 70Zn(n,Y) = 7im4.1 j ZT n h Nat. Abund. 0.62 0.0= *a 1 barn 385,495keY s V

higa s h ha natura n "Z l abundanc hala alsd s fan e ha o lif e similar to **Na and therefore suffers from interference unless chemically separated. "Zn can be used without chemical separation but because of its high natural abundance mus e giveb t t higa n h enrichmena larg s a e d an t dose .e advantag th 7w natura'Z s lo nha f o el abundanc t enrichmenbu e s i t expensive n relatioI . o analysit n e advantagth s 70s Zha n e tha a short t

407 irradiation time e use(10mb dn ca compare) d with **Zn (1-2 weeks)r fo t ,bu these conditions **Zn will produce more activity than 'Z s d sincnha an t i e a long half life compared wite interferinth h g element suc s la *Na(15hh 7 ) J7Cl(38m) 2 week 1- ,o t allo e e sr "Mn(2.58hb lef th fo w tn ca t i ) interfering element o e decameasure t b sd henc an n y ca e d instrumentally. '*Zd 7°Zan nn isotopes have been use o measurt d e zin n humai c n blood following oral administration (14 t sincbu ) e condition e differenar s r fo t analysis of blood compared to faeces it was found that 70Zn was most suitable under these conditions.

Seleniu s anothei m r essential trace elemen n humai t n nutritiod an n to study its absorption in man chicken was labelled with a stable tracer (15), in order that the selenium could be fed to humans in a realistic chemical form, and as an intrinsic label as opposed to an extrinsic one. Selenium has three isotopes suitable for activation:-

7*Se(n,Y)7sSe Ti = 120d Nat. Abund. 0.87$ a = 30 barns Y 135.9,264.6 keV 7'Se(n,Y) = 17.57' rai ST es Nat. Abund. 1 2 9.02 barn= o $ Y 161.s V 9ke •°Se(n,Y)'' = 57.3 i mST me Nat. Abund.49.8 1 barn0. Y 102.s= o $V 9 ke

7'Se enable a slarg e numbe f sample o re analyse b o a short sn i dt s shor it a natura to s t halha time lt du f ei abundanc lift bu e f 9.02o e $ compared with ?*Se(0.87$). For the labelling of the chicken's diet 7''Se e naturath s uset wa bu ld leve f seleniuo l s measurewa m d using 7(Se. This enabled the mass isotopic ratio to be determined before and after administratio e stablth f eo n trace d henc an e degrer th e f enrichmeno e n i t the chicken.

Recent studies using stable tracers as digestive markers have made use of the short lived neutron activation products of the rare earths (16) e.g.

">Dy(n,Y)l'itnDy Ti = 1.26m Nat. Abund. 28.18$ o = 2000 barns Y 108,514 keV 5lEu(n,Y)ls*mEu Ti = 9-36h Nat. Abund. 47.77$ a = 2800 barns Y 122,344 keV "Yb(n,Y)1"Yb Ti = 30.7d Nat. Abund. 0.14$ a = 11000 barns Y 177,198 keV 52Sm(n,Y) = 47.615J i T Shm Nat.V Abundke 3 0 barn10 .21 26.63Y s = $° "La(n,Y) l<>0= 40.3 i LT ha Nat. Abund 9 barn8. .Y 487,923,159 s 99.9 = o $ 6 keV

The rare earth e particularlar s s markera y t r suiteac fo s o t d digestive studies sinc t radiocolloidaa e l concentrations (10~ 7- 10~1! molar) they absorb into and stay bound to particulate matter. Digestibility coefficients can be determined for different types of food- stuff using this technique. The use of rare earths is also becoming more widespread in the environmental field including studies on sea water and fresh water over long periods of time (17).

Current wor t Imperiaa k l College fiel th f stabl o dn i e e tracers covers both biological d environmenta(18an ) ,19 l research (20)r Ou . studier havfa e o s bees o determint n e efficiencth e f iroo y n absorption i n humans under different conditions. It was first necessary to establish thae bodth ty make o distinction s n between naturally occurrine gth irod an n iron labe d alsan lo tha n dietari t y investigation e isotopth s e uniformly label e endogenouth s e tess th irot n i runn . Since ther s onli e a y3.4 $ difference in weight between "Fe and "Fe it is unlikely that isotopic effects woul a problee labellin e th b dd thi d an man s f dieo g t were showo t n be satisfactory by conducting some preliminary experiments on rats using both stable enriche e (fro"F d m 0.3 1o 66$t d radioactiv)an e "Feo N . differences in iron absorption were found. The techniques of faecal monitorin r determininfo g e bioavailabilitth g f iro o yn huma i n n subjects

408 s beeha n discussed earliet mus i e remembere b t bu r d thae advantagth t f o e usin a stablg e isotope ove a radioisotoper , i.e. safety mus e weigheb t d against the disadvantages (high loss, difficulty of measurement, poor analytical precision and high detection limits). This leads to an argument for setting up hypotheses using animal models and radiotracers, then testing them in man using the stable tracer. Using our Reactor and enriched stable *'Fe a detection limi f 0.0o t g 1**Fu e wit o chemican h l separatio s obtainewa n n asheo d d faecal samples. Preliminary experiments on rats showed that the level of iron in the diet given during the preceedin 3 day1- gs befor e testh e t a dramati mead ha l c influenc n iroo e n absorptio e subsequenth f o n t test meal d studiean , n eleveso n healthy adult human volunteers supported this finding. When thes y (a wer e F e g givem 0 5 n FeSO a placebo r u)o , followed eightee s FeSO.(a n e hourF ) g m s 0 late1 y b r labelled with 1.3 mg *'Fe there was a significant reduction (P<0.01) in the proportion of iron retained after the Fe-load (0.290 SEM 0.051) compared to the placebo (0.35 M 0.046SE 4 ) which suggests that previous iron intaks ha e a direct influence on the subsequent iron absorption from food or iron preparations. Stable iron tracer studie e currentlar s n progresi y o t s asses e absorptioF s e footh d n d infanti nmanufacturerai o t s n theii s r choice of formulation for infant foods in terms of quantity and chemical forms of iron. Fe absorption from **Fe labelled bovine lactoferrin, in new-born infant s beini s g compared with that from well-absorbed ferrous sulphate. Another study is underway to investigate the potential of **Fe enrichment in blood cells for studying the availability of iron rather than faecal monitoring. Preliminary results for a study of non-anaemic men from Gambia investigating iron absorption from FeSO^ or a typical Gambian meal, labelleg du F ewit0 sho69 h a wsignifican t correlation betwee% n absorptio 58 n measured by faecal monitoring and ''Fe-enrichment in the blood ten days later. Measurements by INAA have proved sensitive enough even with a relatively small dose of "Fe and would suggest that blood cell measurements could replac e morth ee time-consumin d lesan g s accurate technique of faecal monitoring.

e environmentath n I l fiel e havw d e used dysprosium (without enrichment) to study the spray drift within and derived from plots of winter wheat treated with a pesticide spray. There is increasing awareness e importancth f o f moro e e efficient method f applicatioo s o reduct n e chemica lo decreast cost d an s e harmful side effects. Dysprosius wa m incorporated in the spray liquid at a concentration of 1.3g dysprosium chloride per litre (0.56g Dy/L). Samples were taken in the field using filter paper t differena s t height d distancean s s froe sprath m y pointd an s S systemirradiateCA e e minutd counteon th ,an n r decayes r i e1 fo dfo d r fo d e minuton e givin a gdetectio n limi f o 1.6t 2 x . 10~Dy Measurabl g Jvi e amounts of dysprosium could be detected at up to 100m derived from the spray point. We are currently engaged in studies of foliar deposition of radionuclides onto crops in the field and also under controlled conditions ia winn d tunnelo thid o s T e fielsafel.th dn i ysurrogate e user ar sfo d the radionuclides a usefuincludin( u E l , surrogat Dy ge actinides) th r fo e . It is hoped to extend this work to study uptake of these tracers in human volunteers to mimic the radionuclide metabolic pathways.

This paper has shown the potential for the use of stable tracers both in biological and environmental research and has attempted to point out the advantages and disadvantages. In summary the stable tracer has the advantage of safety when applied to humans and the environment but the disadvantages of high cost for the enriched tracer although in the environmen a t'rare ' tracer suc s dysprosiua h e useb dn ca withougm h enrichment, the requirement of an activation analysis facility and possible chemical processing for sensitive analyses although using a tracer producing a radionuclide with a short half life and high cross section enables large numbers of samples to be analysed instrumentally.

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. 8 CURRIE V.E., LENGEMANN F.W., WENTWORTH R.A., SCHWART . R ZStabl g "M e n vivi on a trace s a n investigatioi r f magnesiuo n m utilisation. Int. . NuclJ . Med .4 Biol 159-162 ._ 4 (1975).

9. JOHANSEN 0., STEINNES E. A Method for the use of indium as an activable trace n pollutioi r n . studiesApplJ . .In Rad. .& Iso 7 2 . 163-167 (1976).

. TIN10 G B.T.G., PAGOUNE , JANGHORBAN . J S , YOUN . M I G V.R. Radiochemical neutron activation analysi f stablo s e isotope n relatioi s o humat n n nutrition. 6th Modern Trends in Activation Analysis Conference 1981.

11. JANGHORBANI M., TING B.T.G., YOUNG V.R. Absorption of iron in young men studied by monitoring excretion of a stable iron isotope (5*Fe) in faeces . NutrJ . . JMC i1 ( 12190-219) 7 (1980). 12. JANGHORBAN , YOUNM. I Gf stabl o V.R e Us e. isotope o determint s e bioavailability of minerals in human diets using the method of faecal monitoring. Am. J. Clin. Nutr. J33_ 2025-2030 (1980).

13. YOUNG V.R., JANGHORBANI M. Soy protein in human diets in relation to bioavailability of iron and zinc : A brief overview. Cereal Chem. 58_(1) 12-18 (1981).

14. JANGHORBANI M. , TING B.T.G., ISTFAN N.W., YOUNG V.R. Measurement of 7 d *Zhuman i an n n nZ bloo' ' n referenc i dstude f th zino yo ct e metabolism. Am. J. Clin. Nutr. 34 581-591 (1981).

410 15. JANGHORBAN , MERRILM. I L J.C., STEINKE F.H., YOUNG V.R. Feasibilitf o y intrinsic labelling of poultry meat with stable isotope of Selenium n humai e n( us 7metaboli*Se r fo ) c studies . NutrJ . . 111(5) 817-822 (1981).

16. KENNELLY J.J., APPS M.J. Routine measurement f selecteo s d digestive markers using their short lived neutron activation productsh 6t . Modern Trends in Activation Analysis Conference 1981.

17. DRABAE . I KAnalysi d timan s e stabilit f activablo y e hydrospheric tracers . RadioanalJ . . Chem. 75_(1-2) 97-106 (1982).

18. FAIRWEATHER-TAIT S.J., MINSKI M.J., RICHARDSON D.P. Iron absorption fro a maltem d cocoa drink fortified with ferric orthophosphate usina g stabl n extrinsia e s isotopa e c "F elabel . B.J. Nutr 51-6_ 50 . 0 (1983).

19. FAIRWEATHER-TAIT S.J., MINSKI M.J e effecTh . f iron-loadino t n o g subsequent iron absorption. B.J. Nutr. (in press).

. DOBSO20 N C.M., MINSKI M.J., MATTHEWS G.A. Neutron activation analysis using dysprosium as a tracer to measure spray drift. Crop Protection 2(3) 3^5-352 (1983).

411 LIS PARTICIPANTF TO S

. 10 J-M. Baugnet J.A. Izatt SCK/CEN Scottish Universities Research Boeretan0 20 g and Reactor Centre B-2400 Mol East Kilbride BELGIUM Glasgow, G75 OQU SCOTLAND P. Hiismaki Otakaari 3 A 11. E. Kenney SF-02150 Espoo Pennsylvania State University FINLAND College of Engineering University Park A ,1680P 2 J-M. Cerles USA Servic s Pilede e s CEN Saclay 12. V. Dimic B.P. No. 2 Institut Jozef Stefan 91191 Gif/Yvette Cedex P.O. Box 100 FRANCE 6111 Ljubljana YUGOSLAVIA J. Garcin CEN/Grenoble 13. Z. Szatmäry Servic s Pilede e s Central Research Institut B.P. No. 85X for Physics F-38041 Grenoble Cedex 9 4 P.Ox Bo . FRANCE 1525 Budapest 114 HUNGARY W. Krull GKSS Forschungszentru. 14 m G. Keomley Reaktorstrasse 7 Central Research Institut D-2054 Geesthacht-Tesperhude for Physics FEDERAL REPUBLI GERMANF CO Y 9 4 P.Ox Bo . 1525 Budapes4 11 t . ZiegenbeiD n HUNGARY Central Institute for Nuclear . 15 Research S. Elo Rossendorf Nuclear Training Reactor GERMAN DEMOCRATIC REPUBLIC Technical University Myegyetem rkp.9/11 C.L. Thaper I BudapesX t Nuclear Physics Division HUNGARY Bhabha Atomic Research Centre Trombay, Bombay 16. F. Levai INDIA Nuclear Training Reactor Technical University J. Koziel Myegyetem rkp.9/11 ORIPI-IEA XI Budapest Institute of Atomic Energy HUNGARY 05-400 Otwock-Swierk POLAND

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