This report summarizes the results of EPRI’s multi-year research effort to assess cladding
performance under normal and hypothetical accident conditions of spent nuclear fuel
transportation.

Due to the delayed opening of a final geological repository for spent nuclear fuel, the lifespan of dry cask storage systems may be increased to 120 years or longer. To ensure safety over this extended period of interim storage, degradation mechanisms that have the potential to cause penetration of the canister confinement boundary must be evaluated and understood.

The Used Fuel Disposition (UFD) Transportation Task commenced in October 2010. As its first task, Pacific Northwest National Laboratory (PNNL) compiled a list of structures, systems, and components (SSCs) of transportation systems and their possible degradation mechanisms during extended storage. The list of SSCs and the associated degradation mechanisms [known as features, events, and processes (FEPs)] were based on the list of used nuclear fuel (UNF) storage system SSCs and degradation mechanisms developed by the UFD Storage Task (Hanson et al. 2011).