Methodology of delayed hydride cracking assessment of spent fuel cladding

During dry storage, the spent fuel claddings could degrade through hydrogen-related degradation mechanisms. DHC (Delayed Hydride Cracking), which is a time dependent crack growth process resulting from stress assisted hydrogen diffusion to the crack tip, is considered as a main concern. In this regard, NRC, DOE, and EPRI also recognized that DHC is a potential cladding breach mechanism after⁓100 years of dry storage, but relevant test data are limited. In this regard, DHC assessment procedures using threshold stress intensity factor (KIH) are proposed and applied to PWR spent fuel cladding. DHC is considered as a most potential cladding breach mechanism for spent fuel cladding. The assessment procedures of that using threshold stress intensity factor (KIH) are proposed and applied to PWR spent fuel cladding.