A thermal analysis was made of a storage concept for a reference intact spent fuel assembly encapsulated in a metal matrix in a cylindrical canister. Maximum temperatures within the canister, as well as the canister surface temperatures, were estimated for interim storage of canisters in environments of a water basin, an air basin, and a vertical sealed storage cask. Comparisons of the thermal analyses of the metal-encapsulated concepts were made with a canister with an air filler (i.e., no metal encapsulation). A similar analysis was also made for a concept employing sheared spent fuel segments rather than an intact fuel assembly.