Concept of hydride fuel target subassemblies in a fast reactor core for effective transmutation of MA

U-Th-Zr alloys with four different compositions were hydrogenated and examined for their hydrogen holding capacities, microstructural and hardness changes with irradiation and thermal diffusivities. Considerably high hydrogen capacity was confirmed up to about 1173 K. A certain degree of irradiation stability was observed, and relatively high thermal diffusivity was ascertained for these hydrogenated ternary alloys. Based on these results, a new concept for effective transmutations of MA was proposed, where target assemblies containing Np and Am in hydrogenated form are loaded in a fast reactor core. This concept has a great potential to achieve the best transmutation of MA with improvement of safety characteristics in a fast reactor core. (C) 1998 Elsevier Science S.A.