Long-term R&D plan on LMFBR safety research; Reactor safety R&D plan

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A long-term program plan was explored by the members of Reactor Safety Section(RSS), O-arai Engineering Center, Power Reactor and Nuclear Fuel Development Corporation(PNC) for the future research and development(R&D) on the safety of liquid-metal fast breeder reactors(LMFBRs). The main objeetives of this program plan are to fulfill the requirements raised during the licensing of Monju, and to support the conceptual design and licensing of a future demonstration plant. The current program plan is restricted to R&D areas on the assessmpnt of reliability or integrity of the reactor primary system, which is the ultimate goal of PNC/RSS. Key issues are extracted based on the detailed review of the current status and understanding of the individual R&D areas. They are discussed in this report with emphasizing their needs and priorities. In summary, the future R&D in PNC/RSS should be directed toward: (1)Continuation of the developlment, improvement and verification of the large safety analysis codes such as SAS and SIMMER; (2)Continuation and initiation of out-of-pile and in-pile experimental studies to verify the above computer codes; (3)Continuation of international participation in the large code developments and in-pile experiments; (4)Initiation of an experimental study on the behavior of the molten core materials which is important in assessing the thermal consequences of an accident; (5)Method development for a mechanistic post-accident heat removal analysis; and (6)Scenario development on local-fault sequences to achieve the early detection and termination of the accidents.