IAEA/AL/088 XA0103394 RAPID INSTRUMENTAL AND SEPARATION METHODS FOR MONITORING RADIONUCLiDES IN FOOD AND ENVIRONMENTAL SAMPLES Final Report on an IAEA Co-ordinated Research Programme Vienna, Austria, 1995 -.1 RAPID INSTRUMENTAL AND SEPARATION METHODS FOR MONITORING RADIONUCLIDES IN FOOD AND ENVIRONMENTAL SAMPLES Final Report on an IAEA Co-ordinated Research Programme Vienna, Austria, 1995 IAEA/AL/088, Vienna (1995) A report prepared by the IAEA's Physics, Chemistry and Instrumentation Laboratory Agency's Laboratories, Seibersdorf Division of Research and Isotopes P.O. Box 100, A-1400 Vienna, Austria TABLE OF CONTENTS Summary Report i-vii Rapid separation and liquid scintillation spectroscopic determination of Sr-89, Sr-90. and transuranium elements of interest. K. Buchtela, F. Schonhofer, F. Grass 1 Rapid methods for strontium determination in environmental samples K. Buchtela 8 137Cs Pre-Concentration from water samples using Prussian blue impregnated ion-exchanger. J.M. Godoy, J.R.D. Guimaraes and Z. L. Carvalho 15 Quantitative analysis of ^-emitting fission products E.I. Vapirev, A. V. Hristowa, P.A. Grosev, L T. Tsankov 21 Rapid correlation assessment of Sr in fallout by gamma-spectroscopy F.I. Vapirev, A.V. Hristova 36 Development of rapid analytical methods for Sr-89/90, Pu-239/40 and Pu-238 activity concentrations in fallout, surface water, plants and aerosol filters based on modified routine used analytical procedures H. -U. Siebert, J. Thiele, M. Lonnig, M. Kunert, H. Kranl 53 Rapid in situ gamma spectrometric determination of fallout radioactivity in the environment P. Zombori 69 A new method for the determination of radionuclide distribution in the soil by in situ gamma-ray spectrometry P. Zombori, A. Andrasi, I. Nemeth 83 Live monitoring of cattle, reindeer and sheep P. Strand 116 Quick estimation of separate radionuclides activity concentration in spectrometrically measured samples A. Pietruszewski 120 Rapid determination of strontium-89 and strontium-90 in food and environmental samples by Cerenkov counting J. Me/in, J. Suomela 151 Rapid instrumentation and separation methods for monitoring radionuclides in food and environmental samples MM. Beach 160 Rapid methods for measuring radionuclides in food and environmental samples R.W. Perkins 172 Determination of Sr-89/90 B. Smodis, Z. Planisek, P. Stegnar 186 Development of rapid analytical methods for Am-241 A.R. Byrne, A. Komosa, M. Dermelj, P. Stegnar 193 Rapid determination of 90Sr by TBP extraction S. Zhu, S. Long, Z. Xiao 200 Rapid determination of plutonium by extraction and grid ionization chamber S. Zhu 212 An instrument based on an insertion probe for monitoring radionuclides in bulk foodstuffs EL. Cooper, R.J. Cornett, P. Wong, K.W. Seo 217 Guidelines for planning and design of mobile radiological units R. Schelenz 230 Determination of radiostrontium in soil samples using a crown ether N. Vajda, A. Ghods-Esphahani, P.R. Danes'i 267 Rapid instrumental and separation methods for monitoring radionuclides in food and environmental samples AS. Bhat, V.K. Shukla, A.N. Singh, C.K.G. Nair, S.B. Hingoranir N.N. Dey, S.K. Jha, D.D. Rao 297 SUMMARY REPORT 1. INTRODUCTION The Co-ordinated Research Programme (CRP) on Rapid Instrumental and Separation Methods for Monitoring Radionuciides in Food and Environmental Samples was established by the Agency following a Consultants' Meeting on the same topic, which was held 5-9 September 1988 in Vienna [1 ]. It was completed in 1992. At various times during its course it encompassed 15 participants from 14 countries. The scope of work and objectives of the CRP were established at the Consultants' Meeting [1]. It was agreed that the CRP should focus on the development of rapid methods for the determination of radionuciides in food zind environmental samples during the intermediate and late post-accident phases. The rapid methods developed during the course of the CRP were intended to permit a timely and accurate determination of radionuciides at concentrations at least one order of magnitude below those specified for Derived Intervention Levels (DILs) for food by the WHO/FAO [2] and the IAEA [3]. Research Co-ordination meetings were held in Warsaw, Poland in September 1989 [4] and in Vienna, Austria in 1991 [5]. Reports of the meetings are available from the Agency on Request. This document comprises copies of final reports from the participants and selected contributions presented by the participants at the meetings. The contributions were selected on the basis of being able to stand alone, without further explanation. Where there was an overlap in the information presented by a participant at both meetings, the most complete contribution was selected. 2. SUMMARY OF MAIN ACHIEVEMENTS The main achievements of the CRP included both instrumental methods and chemical separations. Instrumental Methods A significant number of advances in instrumental methods were made during the course of the CRP. These advances are outlined below: a. An efficiency calibration method for a gamma spectrometry system, consisting of a germanium detector and multichannel analyser, has been developed. This method was designed to provide very rapid quantitative results for samples of different sizes and densities in an emergency situation . A computer program and detailed information on detector type are required. A procedure was also proposed for the rapid interpolation of detector efficiency at precise energies for any sample with a density within a range of sample densities. b. A rapid method has been developed for estimating the upper limit of 89Sr and 90Sr in thin deposition samples (eg. air filters and hot particles). It combined measurements of the ^'Cs/^Sr ratio by beta spectrometry in 1987 and 1991 with a measurement of the 14OBa/137Cs ratio from a gamma spectrum taken in 1986 to obtain the Ba/Sr ratio in the reactor core. This ratio can be used to estimate the radiostrontium activity level in samples. c. A rapid method has been developed for separate determination of 89Sr, 90Sr and ^ by beta-spectrometry in air filters, fallout and chemically treated samples. d. A method has been developed for the rapid estimation of gamma-emitting radionuclides (e.g. 137Cs) in near surface soil core profiles, using measurements by gamma spectrometry and exponential depth profile calculations. This procedure is a significant improvement over conventional core profile assessments, in that lengthy sampling and analysis are avoided. e. A method was described for the in-vivo assessment of 137Cs in animals using a Nal detector. At a 95% confidence level, it was shown that the uncertainty in measuring the activity level in muscle tissue was 11 % for cattle, 8% for sheep and 7% for reindeer. f. The applicability of using a "radwaste drum assayer" for the direct measurement of radionuclides in bulk food was assessed. This instrument can detect gamma emitters at 3.7 to 37 mBq/g levels and transuranic radionuclides at approximately 37 Bq/g. It can also detect 90Sr, based on measurement of bremsstrahlung radiation from 90Y, but not with the required sensitivity to meet the DIL. g. The applicability of using solid state detectors for the determination of 241Am by gamma spectrometry was demonstrated and methods both with and without chemical separation were developed. h. The utility of inductively coupled plasma/mass spectrometry (ICP/MS) for the rapid, nearly complete isotopic analysis of any form of sample was described. Currently ICP/MS can detect 108 to 109 atoms of plutonium, uranium, and other radionuclides. Ongoing and future development, including efficient sample introduction techniques, single ion counting, and high resolution mass spectrometry may ultimately increase the sensitivity to 107 atoms, for radionuclides with a half-life of more than one year. i. The feasibility of designing a thin probe (2.5 cm diameter with a 1.25 cm diameter x 5 cm long Nal(TI) detector) for monitoring 137Cs in bulk food was described. Measurements with this detector are rapid and sufficiently sensitive to determine 137Cs at levels in food which are below WHO limits. j. Simple, but specially designed spectrometric instrumentation for the rapid monitoring of gamma-emitters in food and environmental samples was described. k. A parallel grid ionization chamber was shown to be useful for determining a- emitters in water, ashed grass, soil and air filters, without the need for prior chemical work-up. One of the highlights of the second CRP meeting, was a presentation on designing a state-of-the-art mobile laboratory that can respond immediately after a nuclear accident. The primary purpose of this mobile radiological unit is to limit the radiation exposure to the general public by monitoring environmental samples and foodstuffs. Chemical Separations Rapid methods for radiochemical separation have now reached the state where results can be obtained within one working day. Some of the achievements related to rapid radiochemical separations are outlined below: a. A simple pre-concentration procedure for the rapid determination of 241Am with greater sensitivity by gamma spectrometry was developed. This procedure has been applied to the analysis of Chernobyl soil samples. b. Several methods, utilizing either TBP or HDEHP, for the liquid extraction of 90Y, have been developed to determine radiostrontium levels in a variety of sample matrices. Results for both 89Sr and 90Sr activity levels can be obtained during one working day. These methods have already been applied routinely to Chernobyl samples. c. It has been demonstrated that the application of crown ethers for radiostrontium determination is successfully competing with the more highly developed rapid liquid extraction procedures for 90Y. Currently, the separation and determination of radiostrontium in soil can be carried out in about 8 hours. It is expected that radionuclide isolation using crown ethers may become a routine technique in the near future. d. An assembly has been constructed for the in-situ preconcentration of radionuclides from water. When the assembly contains Prussian blue impregnated ion-exchange resin, it can successfully pre-concentrate 137Cs from volumes up to 10 liters at flow rates of 2 L/min.