Development of heat and mass transfer model for analysis of material relocation phase in fast reactors

高速炉の物質再配置過程解析のための熱及び質量移行モデルの開発

守田 幸路*; 山野 秀将   ; 飛田 吉春

Morita, Koji*; Yamano, Hidemasa; Tobita, Yoshiharu

A new computer code, SIMMER-LT, is under development to simulate long-term behavior of disrupted core materials with reactivity insertion. Although it is based on the framework of the transition-phase analysis code, SIMMER-III, improvement of computational efficiency is necessary for simulations of longer transients. Therefore, equilibrium vaporization/ condensation (V/C) models were newly developed for SIMMER-LT to reduce computational load in multi-component heat and mass transfer calculations. The developed model was validated through numerical simulations of a sodium boiling experiment in pin-bundle geometry under a loss-of-flow condition. SIMMER-LT reproduces characteristics of sodium boiling observed in the experiment reasonably with no essential difference from results obtained by SIMMER-III. The present results demonstrate that SIMMER-LT using the equilibrium V/C models is applicable to slowly transient phenomena of heat and mass transfer expected in material relocation phase.