抄録
An analysis of JOYO MK-II natural circulation tests has been performed to evaluate the applicability of the fast reactor plant dynamics code super-COPD to natural circulation decay heat removal phenomena. In this analysis, it was found that natural circulation behavior is much influenced by the coolant mixing regime in the upper plenum of the reactor vessel. The predicted transient behaviors of the core outlet coolant temperature and the primary flow rate showed good agreement with the test results by using a variable mesh partitioning method and by setting appropriate mixing volume in the upper plenum region which can include the effect of thermal stratification phenomena on the natural circulation behavior.
