1157.流れと温度分布を考慮した溶融塩炉の定常炉心特性

抄録

The Molten Salt Reactor (MSR) is a thermal neutron reactor with graphite moderation and operates on the thoriumuranium fuel cycle. The notable feature of the MSR is that fuel salt flows the inside of the reactor accompanying nuclear fission reaction. In the previous study, the authors had developed numerical model to simulate the effects of the fuel salt flow on reactor characteristics and estimated the basic effects in a simplified system. This paper applies the model to the steady state analysis of the MSR system and simulates the effects of not only fuel flow but also fuel salt inflow temperature and residence time in the 1^st loop system. The model consists of two group diffusion equations for fast and thermal neutron fluxes, balance equations for six-group delayed neutron precursors and energy conservation equations for fuel salt and graphite moderator. The following results are obtained: (1) the fuel salt flow affects the distributions of the delayed neutron precursors, especially long-lived one, and (2) the extension of residence time in the 1st loop system and the rise of fuel inflow temperature shows negative reactivity effects, decreasing neutron multiplication factor.