Long-term safe storage of spent nuclear fuel (SNF) determines sustainability of the current light
water reactor (LWR) fleet. In the U.S., SNF is stored in stainless steel canister in dry cask storage
system (DCSS) after spending several years in wet pool storage system while there is no DSCC in
Republic of Korea. The SNF storage time in DSCC is expected to be multiple decades since no
permanent geological repositories are identified in both countries. One limiting factor for extended
storage of SNF in DSCC is chloride-induced stress corrosion cracking (CISCC) in the welded regions
of the stainless steel canisters. The propensity for the occurrence of CISCC has warranted the
development of the mitigation and repair technologies to ensure the safe and long-term storage for
both present and new canister although no CISCC failure was reported yet.
This study investigates cold spray deposition coatings of 304 L and 316 L stainless steels on
prototypical stainless steel canisters such as sensitized flat and C-ring samples. The cold spray
technology has been identified as the most promising approach by Extended Storage Collaboration
Program (ESCP) driven by Electric Power Research Institute (EPRI). The talk includes microstructural
characterization, adhesion strength measurement, residual stress evaluation, and corrosion behavior of
the coated materials in boiling MgCl2 solution and electrochemical corrosion tests in NaCl solution. In
addition, the capability of repair of cracks on the canister surface using the coating technology will be
presented.