Spent-fuel performance during dry storage

Dry storage of spent fuel is a technically viable storage mode. Major factors in assuring adequate spent fuel performance during storage are: (1) the condition of the fuel, (2) the storage temperature, and (3) the atmosphere. These are important for design, licensability and operation of the four dry storage modes normally considered. Laboratory investigation and experience are needed for establishing the appropriate trade-off ranges and design limits. The cost of dry storage can be minimized by investigating spent fuel performance. Once we have a clear understanding of spent fuel behavior, then numerous trade-offs can be considered in system design. For instance: (1) degree of surveillance versus canisterization, (2) fuel storage temperature versus canisterization, and (3) gross breaches with canisters in air or no breaches with canisters in air. There are many more trade-off examples which can be evaluated once the performance of the spent fuel is known. Satisfactory fuel performance is essential to the design, licensing and acceptance of dry storage systems. The performance of the fuel can largely be considered independent of the particular storage mode, particularly during the actual storage period, in that performance is only affected by temperature and storage atmosphere. System design and handling processes thatmore » influence the temperature and storage atmosphere will naturally affect fuel performance. Specific factors which affect fuel performance that may be mode dependent include pre-storage induced damage to the fuel rods and potential off-normal responses of the storage system to loss of coolant system or containment. With these factors which affect fuel behavior kept in perspective, spent fuel performance during dry storage can be investigated from a generic viewpoint without regard for specific storage mode dependence.« less