高速炉の炉停止失敗事象における炉容器内終息（IVR）に関する検討

(2) ULOF再配置／冷却過程における評価

抄録

The achievement of In-Vessel Retention (IVR) of the accident consequences in an unprotected loss of flow, which is one of the technically inconceivable events postulated beyond design basis, is effective and rational approach in enhancing the safety characteristics of sodium-cooled fast reactor. The objective of the present study is to show that the decay heat generated from the relocated fuels would be stably removed in the post-accident-material-relocation/post-accident-heat-removal phase, where the relocated fuels mean the fuel discharged from the core into the low-pressure plenum through control-rod guide tubes, and the fuel remnant in the disrupted core region (non-discharged fuel). As a result of the present assessments, it should be concluded that the stable cooling of the relocated fuels was confirmed and the prospect of IVR was obtained.