Publications Details
International perspectives on technical data gaps associated with long term storage and transportation of used nuclear fuel
Various circumstances around the world have resulted in the potential need to store used nuclear fuel longer than times allowed by the regulations. While current storage of used fuel is safe and is likely to remain safe for extended periods of time, material degradation issues may arise that have not necessarily been considered when used fuel storage was licensed for relatively short periods of time. Material degradation issues associated with the fuel, cask internals, storage overpack, closure seals and bolts, and the storage pad all need to be assessed relative to long term performance. Key functional requirements for this long term performance include subcriticality, containment, shielding, thermal performance, and retrievability. A sufficient degree of understanding of the material degradation issues relative to the functional requirements for storage is necessary to develop the technical basis to ensure material performance over extended periods of time. An important initial step in addressing material degradation issues is to identify technical data gaps relative to existing understanding that are important over long storage periods. An effort has been under way since June 2010 to develop a list and prioritization of technical gaps from an international perspective. This effort is being conducted under the aegis of the U.S. Electric Power Research Institute (EPRI) Extended Storage Collaboration Program (ESCP). As part of this program, an International Subcommittee has been established to solicit the international community's input on storage system material degradation issues associated with long term storage and transportation. The first goal of this subcommittee is to develop a report on the technical data gaps from an international perspective. Since used fuel is stored in various configurations around the world, it is expected that different priorities will be identified relative to importance in maintaining the key performance functions. The second goal of the subcommittee is to identify areas for international collaboration for research on degradation issues in order to leverage existing program and facilities. The current status of the international data gap effort is a draft list of High, Medium, and Low priority issues that should be addressed to demonstrate sufficient understanding of material performance of storage system components over extended operational periods. Although there are differences in the identified gaps and associated priorities due to different regulations and storage and transportation systems, there are also areas of commonalities that are important to recognize. These are the areas that have the greatest potential for collaboration.