SAFETY OF INTERIM STORAGE SOLUTIONS OF USED NUCLEAR FUEL DURING EXTENDED TERM

摘要

For the sustainability of nuclear energy, three important principles related to interim used nuclear fuel (UNF) management apply: 1. First and foremost, security and safety of the material must be provided at all times. 2. Second, UNF should be managed in such a way that will not impose undue burdens to future generations and there should be an end point to the interim storage. 3. Third, retrievability is a key parameter for safe management of UNF. Numerous countries are still assessing and implementing durable UNF management solutions. As implementation of UNF recycling is not yet decided and since final disposition of UNF has not yet been resolved in many countries, wet and dry storage solutions have had to be deployed to support continued plant operations. Intermediate storage of UNF under dry and wet conditions has been performed safely and reliably as shown by industrial feedback and operational records, but storage durations are constrained by regulatory limits. These limits are typically 20 to 40 years. Wet storage has been implemented for more than 40 years and dry storage has now reached 35 years in a few countries. With the need to extend the interim storage durations for UNF in numerous countries, additional technical evaluations are needed to better understand the optimum duration of such solutions. This paper will provide an overview of the status of wet and dry storage conditions in countries with long histories of UNF storage and will also include information on industrial experience with alternative interim solutions. In conclusion, a description of the progress that needs to be made through research and development (R&D) investigations that will support safety over the longer term and allow for retrieval of UNF when more durable solutions are implemented (e.g., recycling and/or deep geological repository).