Experience in the Management of Radioactive Wastes After Nuclear Accidents: a Basis for Preplanning
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IAEA NUCLEAR ENERGY SERIES NW-T-1.31 Experience in the Management of Radioactive Wastes After Nuclear Accidents: A Basis for Preplanning Please note: This is a final draft version made available as a preprint advance publishing copy for reference only. This version may contain errors and is not the official IAEA publication. Consistent with the relevant terms of use, the IAEA does not make any warranties or representations as to the accuracy or completeness of this version. To cite this preprint please include ‘preprint’ in the full reference. Any quotations or other information taken from this copy may change in the final publication so please always check the official published version. When it is released a link will appear in the preprint record and will be available on the IAEA publications website. The terms of use of this preprint are the same as those for the IAEA publications – free to read but preprints may not be translated. 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Enquiries should be addressed to the IAEA Publishing Section at: Marketing and Sales Unit, Publishing Section International Atomic Energy Agency Vienna International Centre PO Box 100 1400 Vienna, Austria fax: +43 1 2600 29302 tel.: +43 1 2600 22417 email: [email protected] http://www.iaea.org/books For further information on this publication, please contact: Nuclear Power Technology Development Section International Atomic Energy Agency Vienna International Centre PO Box 100 1400 Vienna, Austria Email: [email protected] © IAEA, 2021 IAEA Library Cataloguing in Publication Data FOREWORD Major accidents at a nuclear power plant or fuel cycle facility are rare but can produce large quantities of radioactive waste with widely varying characteristics that can be difficult to manage. This is illustrated by the challenges faced at the Three Mile Island Unit 2 accident in 1979 and the continuing challenges following accidents at the Windscale Pile in 1957, Chornobyl nuclear power plant in 1986 and the Fukushima Daiichi Nuclear Power Station in 2011 (see Appendices I–IV). Large volumes of radioactive waste can also be generated by accidents at military installations or by mishandling high-activity sealed radiation sources (see Appendix V). The need to manage equivalent, large volumes of wastes from the cleanup of some legacy nuclear sites can also provide valuable experience for handling accident wastes (see Appendix VI). Implementing safe, cost effective management of waste from a major nuclear accident has proven to be a complex, resource intensive undertaking. Substantial challenges can also arise in the case of smaller accidents. Decisions need to be made on the designs and technologies to be employed to treat and dispose of a diverse mix of waste constituents, and on the selection of sites to be used for predisposal waste management and for the disposal facilities themselves. In the case of a major accident, radioactive waste volumes can quickly overwhelm existing national management and disposal infrastructure. Appropriate disposal facilities might not be available to match the amounts or characteristics of the wastes. Under such circumstances, inappropriate response actions taken in the early aftermath of an accident can limit the range of future management and disposal options, substantially increase costs and result in significant worker exposures and increased risk of public exposures. It will help to avoid such situations if precautionary accident response preplanning has been undertaken, even where the likelihood of serious accidents is considered to be extremely low. Exercises involving potential accident scenario identification and analysis, linked to response planning carried out at both national and facility level, are recommended. Such exercises can increase the likelihood that the processes used and decisions made in the event of an accident will be effective and broadly understood and accepted. Expanded knowledge from addressing wastes resulting from the Chornobyl and Fukushima Daiichi accidents, as well as experience with legacy nuclear fuel cycle and nuclear weapons facilities, non-nuclear accidents and radiological incident waste estimation tools offer valuable lessons for proactive, preplanning and strategy development. The potential for serious events at small facilities with radiologically significant material inventories has been demonstrated by historical events such as the SL-1 and Fermi 1 reactor events in the USA Both these events involved core damage and extensive generation of radioactive waste. Substantial experience has also been gained in many Member States in managing significant legacy radioactive waste in a suitably protective, cost effective manner using different approaches (see Appendix VI). This has led to improved operational approaches and provided experience in applying exemption and clearance principles. Although the nature and scale of any future nuclear accident that results in contamination of the environment are not predictable, a number of aspects can be anticipated and incorporated into advance planning and preparation, improving response and recovery capability. Given the diverse nature of wastes produced by major accidents, a graded approach to their management is recommended based on the potential characteristics of the waste involved. In the case of major accidents, multiple waste management facilities employing different designs can provide versatile options while controlling costs, without compromising safety or environmental protection standards. Waste management challenges depend on the scope and severity of an accident, as well as on the stage of the incident. The early emergency response stages may pose particular challenges when decisions need to be made quickly, limited personnel and facility availability, and when the priority of the moment will be focused on controlling the emergency itself. Challenges can result from the collection and storage of small amounts of wastes in containers without special treatment; the need to create full scale conditioning systems to capture and stabilize radionuclides and damaged fuel; the requirement to manage a wide range of wastes; working in harsh physical and radiological conditions; etc. Choosing and/or creating a waste management system is dependent upon many factors, such as the amount of waste and its geographical distribution, levels of contamination, physical and chemical properties, techniques and resources available, and storage and disposal requirements and capabilities. Waste management can be a constraint to remediation if appropriate waste management facilities, logistics, and staff support are not available in a timely manner. Integration of the remediation programme and the waste management programme is important. Through robust preparedness planning, Member States can minimize the amount of waste requiring disposal, provide for separation of wastes by type and radioactivity level, process or otherwise prepare stored waste for disposal and then dispose of it, all in a safe, efficient and cost effective manner. Achievement of these interrelated objectives is always conducted in a manner that is protective of workers, the general public and the environment in accordance with accepted standards. The experiences from past major accidents that are summarized in this report are intended to support such preparedness planning. The IAEA officers responsible for this publication were G.H. Nieder-Westermann and F.N. Dragolici of the Division of Nuclear Fuel Cycle and Waste Technology. CONTENTS 1 INTRODUCTION ......................................................................................................................................... 1 1.1