Journal of Nuclear Fuel Cycle and Waste Technology

As the storage capacity of spent nuclear fuel pools at nuclear power plants approaches saturation, dry storage systems are gaining increasing attention as an interim solution. In particular, metallic canister-based systems have been widely adopted due to their operational efficiency and design flexibility. However, the global trend toward higher burnup fuels has emphasized the importance of managing the long-term integrity of internal structural components, which are subject to elevated temperatures and restricted inspection access. This study presents the current status of evaluation system development aimed at managing degradation in key structural materials—namely, 17-4 precipitation-hardened stainless steel and 6061-T651 aluminum alloy—used in dry storage systems. Building upon the framework outlined in the U.S. NRC’s NUREG-2214, aging management reviews have been performed to identify critical degradation mechanisms such as thermal aging and creep under both normal and off-normal conditions. To experimentally support these reviews, thermal aging and creep test systems have been constructed and validated. Testing is being carried out under simulated dry and wet-steam environments, with preliminary data being collected on mechanical property degradation and time-dependent creep behavior. Ongoing efforts include system reliability enhancement, oxide characterization and the refinement of technical bases for future application to aging management programs and time-limited aging analyses. These efforts are expected to support the establishment of a domestic AMP and TLAA for dry storage systems, and contribute to the design advancement and infrastructure development of future interim storage facilities in Korea.

Keywords

Dry storage system, Aging management review (AMR), Thermal aging, Creep, Structural materials degradation