Monitoring of Spent Fuel Condition over Long-Term Storage

The Coordinated Research Projects (CRPs) of the International Atomic Energy Agency (IAEA) are a powerful tool for engaging multiple countries that operate spent fuel storage facilities to address important safety issues at a deep level of competence and expertise. One of the topics that needs thorough research is the behavior and condition assessment of spent fuel assemblies and fuel rods during long/very long-term storage in spent fuel storage facilities. Naturally, over an extended period, special attention is drawn to degradation mechanisms, aging effects and aging management programs that should be implemented to avoid and mitigate the impact of degradation mechanisms on spent fuel elements. Studying aging effects and predicting the condition of fuel assemblies is relevant under the conditions of limited access and need to introduce indirect monitoring means. At the first stage of the research, the Operating Experience on Degradation (Aging Effects) at the Dry Nuclear Fuel Storage Facilities was analyzed. This article describes the second step in implementing the IAEA CRP “T13019. Performance Assessment of Storage Systems for Extended Durations (PASSED)”, with contribution of the State Scientific and Technical Center for Nuclear and Radiation Safety (SSTC NRS), which conducts research regarding the Monitoring of Spent Fuel Condition over Long-Term Storage. As an example, the Dry Spent Fuel Storage Facility on the Chornobyl NPP site has been selected and studied. The overall objective of the research provided by the SSTC NRS is to strengthen technical knowledge, experience and understanding of the long-term behavior of dry spent fuel storage systems, as well as inspection and monitoring technologies currently in use.