Integrating data and analysis capabilities for cask-specific safety evaluations

With used nuclear fuel (UNF) being stored at reactor sites for longer time intervals than originally foreseen, and the expanded use of high-burnup (>45 GWd/MTU) fuel, uncertainties related to meeting regulatory criteria during extended storage (ES) of UNF and subsequent transportation are increasing. Current thermal analysis methods in use typically overpredict the time-dependent temperature profiles by an unknown amount. This can hinder efforts to accurately predict confinement breaches due to low-temperature degradation phenomena and overpredict the number of fuel rods that may potentially fail during extended storage. Overly conservative analysis approximations could lead to prematurely invoking compensatory measures, such as repackaging bare fuel, canisterizing a significant fraction of UNF prior to storage, or requiring additional criticality control prior to transport and disposal (e.g., inserting disposal control rod assemblies). Computational power and tools have progressed to the point that accurate and efficient evaluation of safety margins for specific casks, with consideration of the actual loaded contents, is possible. To facilitate modeling and analysis capabilities for existing storage and transportation cask systems for used fuel management, a centralized, comprehensive, and integrated data and analysis tool system is being assembled-UNF Integrated Data, Experiments, and Analysis System (IDEAS).