Materials requirements for liquid metal fast breeder reactors

Materials requirements for Liquid Metal Fast Breeder Reactors (LMFBRs) are quite varied with requisite applications ranging from ex-reactor components such as piping, pumps, steam generators and heat exchangers to in-reactor components such as heavy section reactor vessels, core structurais, fuel pin cladding and subassembly flow ducts. Requirements for ex-reactor component materials include: good high temperature ten-sile, creep and fatigue properties; compatibility with high temperature flowing sodium; resistance to wear, stress corrosion cracking, and crack propagation; and good welda-bility. Requirements for in-reactor components include most of those cited above for ex-reactor components as supplemented by the following: resistance to radiation embrittle-ment, swelling and radiation enhanced creep; good neutronics; compatibility with fuel and fission product materials; and resistance to mass transfervia flowing sodium. Extensive programs are currently in place in a number of national laboratories and industrial con-tractors to address the materials requirements for LMFBRs. These programs are fo-cused on meeting the near term requirements of early LMFBRs such as the Fast Flux Test Facility and the Clinch River Breeder Reactor as well as the longer term require-ments of larger near-commercial and fully-commercial reactors.