ICONE23-2177 SEVERE ACCIDENT ANALYSIS OF LWR EQUIPPED WITH ISOLATION CONDENSERS EMPLOYING RETRAN/MOD4

Since we experienced the nuclear disaster at Fukushima Daiichi Nuclear Power Station, we can see increasing interest in safety of a nuclear power plant. Such severe accidents tell us importance of passive safety system. In these cases, natural circulation is one of the best solution to make LWR-safety improve. So, we analyzed BWR and PWR equipped with Isolation Condensers (ICs) using the RETRAN/MOD4 code, which is the reactor transient analysis code developed at the Electric Power Research Institute (EPRI) and approved by the US Nuclear Regulatory Commission. We considered that BWR and PWR succeeded in SCRAM and at the same time fell into the Station Blackout (SBO). We put stress on the behaviors of core temperatures, pressures, and water levels of BWR, ABWR, and the PWR Steam Generator (SG). In BWR and ABWR cases, the reactor water levels were kept enough high to cool down the reactor core. In PWR cases, we demonstrated the effects of the Isolation Condenser (IC) to the SG secondary side on the reactor core cooling.