Releases of Radionuclides to Surface Waters at Krasnoyarsk-26 and Tomsk-7 Robert D. Waters Keith L. Compton Vladimir Novikov Frank L. Parker RR-99-3 May 1999 International Institute for Applied Systems Analysis, Laxenburg, Austria Tel: +43 2236 807 Fax: +43 2236 71313 E-mail: [email protected] Web: www.iiasa.ac.at International Standard Book Number 3-7045-0133-6 Research Reports, which record research conducted at IIASA, are independently reviewed before publication. Views or opinions expressed herein do not necessarily represent those of the Institute, its National Member Organizations, or other organizations supporting the work. Copyright c 1999 International Institute for Applied Systems Analysis All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage or retrieval system, without permission in writing from the copyright holder. 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Contents Acknowledgments iv Abstract v 1 Introduction 1 2 Background 4 2.1 Krasnoyarsk Region ......................... 4 2.2TomskRegion............................ 24 3 Sediment Transport and Dose Calculation Methodology 41 3.1GeneralScenarios.......................... 41 3.2 Radionuclides for Evaluation . ................... 42 3.3 Modeling Radionuclide Transport by River Sediment ....... 45 3.4 Exposure: Dose Analysis . ................... 49 4 The Mining and Chemical Combine and the Yenisei River 54 4.1Site-specificScenarios....................... 54 4.2DataandDataAnalysis....................... 55 4.3Results................................ 64 5 The Siberian Chemical Combine and the Tom River 77 5.1Site-specificScenarios....................... 77 5.2DataandDataAnalysis....................... 78 5.3Results................................ 86 6 Conclusions 99 Color Plates 103 Appendix I 106 Appendix II 113 References 115 iii Acknowledgments This work could not have been accomplished without the help and cooperation of Minatom, including the Mining and Chemical Combine (MCC), the Siberian Chemical Combine (SCC), the regional administrations of the Tomsk Oblast and the Krasnoyarsk Krai, the Kurchatov Institute, and the Russian Academy of Sci- ences, including the Institute of Geology of Ore Deposits, Petrography, Mineral- ogy, and Geochemistry (IGEM). Among those participating were Nicolai Egorov, deputy minister of Minatom; Vasili Zhidkov and Alexei Shishlov of the MCC; Georgii Zubkov of the SCC; Leonid Rikhvanov and Yuri Zubkov of the Tomsk regional administration; Nicolai Abramov and Yuri Maltsev of the regional ad- ministration of the Krasnoyarsk Krai; Yuri Gorlinskii and Vladimir Georgievskii of the Kurchatov Institute and Yuri Lapschin and Alla Dvorzhak of the Ukranian Academy of Sciences; and Vasili Velitchkin of IGEM. The joint study with our Russian colleagues, primarily the team led by Vladimir Georgievskii, was undertaken with the intention of using common input data and different mathematical models to determine likely future radioactive material de- position and resultant doses. All Western mathematical models were made avail- able to our Russian colleagues. Although we were able to reach agreement on the substance and text of the conclusions and recommendations of the study, different models, philosophic points of view, and methods of handling experimental data prevented us from reaching complete agreement on the final text. We would like to thank the US Department of Energy for funding this study under Grant No. DE-FG 02-96 EW 13112 and Mr. David Huizenga, acting deputy assistant secretary, Office of Nuclear Material and Facility Stabilization, for his sponsorship of the work. We would also like to thank Gordon MacDonald, director of the International Institute for Applied Systems Analysis (IIASA), for his inter- est in the work and Academician Nicolai Laverov, vice president of the Russian Academy of Sciences, Academician Eugeny Velikhov, president of the Kurchatov Institute, and Deputy Minister Nicolai Egorov of Minatom for their help in improv- ing access to data. iv Abstract During the Cold War, production and testing of nuclear weapons in the United States and the Soviet Union led to major releases of radioactive materials to the environment. Although large studies have begun to clarify the magnitude and im- pact of releases in the United States, only since Perestroika has information become available to begin an evaluation of the significance of releases to the environment in the former Soviet Union (FSU). The Radiation Safety of the Biosphere (RAD) Project at the International Institute for Applied Systems Analysis (IIASA), begun in 1995, is currently evaluating the radiation legacy of the nuclear weapons complex in the FSU. Because the three sites of Chelyabinsk-65 (Mayak Production Asso- ciation – MPA), Tomsk-7 (Siberian Chemical Combine – SCC), and Krasnoyarsk- 26 (Mining and Chemical Combine – MCC) account for the vast majority of the radioactive materials released to the environment in the FSU, these sites are the focus of RAD’s studies. Contamination of such sites has resulted from normal and emergency atmospheric releases (such as the 1993 tank explosion at Tomsk-7), dis- charge of radioactively contaminated waste and cooling waters into rivers, spills and leaks, and deep-well injection disposal of liquid radioactive waste. This study is limited to the impact of past discharges of radioactive materials to the Yenisei River at the MCC and the Tom River at the SCC. Future studies are planned to assess the significance of deep-well injection of wastes at the MCC. This report draws on data ranging from published reports by Western scientists to unpublished data from the sites and affected regions to compile an initial pic- ture of the currently most contaminated portions of these two rivers and to make a preliminary estimate of the potential doses. The report also considers two hy- pothetical scenarios. The first scenario examines the potential for redistribution of existing contamination by a major flood and the significance of the dose resulting from such an event. The second scenario considers a release of radioactively con- taminated sediments from the surface storage basins into the adjacent river with an estimate of the resultant doses. This movement of the contaminated particles is based on an original, unvalidated model. Thus the results, based on incomplete data, provide insight into the magnitude of the problems that might occur but should not be used to determine regulatory compliance or degree of cleanup required. The results of the study indicate that some areas of the Yenisei River flood- plain and island system are significantly contaminated. Conservative estimates of the maximum potential annual dose along the Yenisei are in the range of 5–15 millisieverts (mSv) per year. However, conservative estimates of the potential v vi doses along much of the river are near or below the commonly accepted annual dose limit of 1 mSv per year. Contamination is mainly limited to relatively small areas, particularly in deposition zones around islands and depressions in flood- plains that trap contaminated sediments during floods. Contamination is lower in the Tom River; only within the first few kilometers of the discharge point is there a significant potential for exceeding the 1 mSv annual dose limit. Doses along most of the river are substantially below this level. In addition, data on contami- nation of fish were available for the Tom River: based on conservative estimates, annual doses from fish consumption of up to 3 mSv are possible. This dose is pri- marily due to short-lived activity released from the control systems of the reactor at the SCC. At both sites, the discharge of radioactive material into the adjacent river has been significantly reduced by the shutdown of the single-pass reactors; at the MCC, additional reductions have resulted from reduced processing rates at the site’s reprocessing plant. Based on the results of the hypothetical scenarios, there is no significant poten- tial for extensive contamination downstream from the plants from existing contam- ination along the floodplains and islands. The resulting contamination would be well below background levels and would be essentially undetectable. The increase in the annual dose resulting from such an event is likely to be less than 100 micro- sieverts in the Yenisei River, and substantially less in the Tom River. During a flood, the majority of contaminated sediments resuspended by the higher flows would re- main in suspension for long distances, resulting in a more uniform distribution of radioactive material farther downstream. However, release of highly contaminated sediments from the surface storage basins could result in high contamination levels, particularly near the release point. Because accurate data on the characterization of a hypothetical release were not available, the authors assumed unit releases of a relatively small fraction of the contamination in these ponds. However, even these relatively limited releases resulted in high levels of contamination. Higher releases would likely result in higher levels of contamination, and a large-scale pulse re- lease could result in annual doses exceeding 1 sievert for tens of kilometers along the river if emergency responses were not carried out. It is important to note that discharges into the rivers are not the only pathways for radiological contamination at these