Evaluation on decay heat removal capability of isolation condenser in Fukushima Daiichi Nuclear Plant Unit 1

In this study, we aimed to quantitatively evaluate cooling capacity of isolation condenser (IC) for core cooling in Fukushima Daiichi Nuclear Plant Unit 1. In order to evaluate cooling capacity, we calculated decay heat which was emitted from core. We used the data of nuclear fuel and rated thermal power which is released by TEPCO. Analysis was conducted with TRAC code. We made an experiment in order to check input data for IC. Because analysis data was close to experimental data, we made sure of validity of input data. We analyzed IC under conditions which were recorded when IC started up and tsunami rushed toward plant. As a result of analysis, we confirmed that cooling capacity exceed decay heat under both conditions. In conclusion, IC had a capacity to prevent core meltdown accident in Fukushima Daiichi Nuclear Plant Unit 1. (author)