The Effect of burn-up state on ULOF accident progression of Sodium-cooled Fast Reactor

Onoda, Yuichi ; Ishida, Shinya  ; Yamano, Hidemasa   ; Kubota, Ryuzaburo*

The objective of this study is to investigate the effect of the burn-up state on the ULOF accident progression of ASTIRD type Sodium-Cooled Fast Reactor (SFR). The target core is ASTRID CFV-V3 core, which has MOX fueled axial heterogeneous core, sodium plenum just above the driver core fuel, and low void reactivity. Calculation of ULOF accident progression at the End of Equilibrium Cycle (EOEC) has been conducted using SIMMER code in the frame of the French-Japanese collaboration initiated at the beginning of 2020 on SFR R&D. The result was compared to that at the Beginning of Life (BOL) to see the effect of burn up. The whole core damage was predicted in BOL case, although the core is not damaged in EOEC case. The reason why the fuel pin failure and whole core melting occurred in BOL case is probably due to the combination of channel power level, axial power profile, and flow coast-down history.