Abstract
The loss of coolant accident (LOCA) is an important design basis accidents (DBA) for the nuclear power plants, because it may challenge the containment structure integrity and let the fission products released to the environment. This thesis has investigated the main steam line break and the pump suction rupture of the cold leg for the Maanshan nuclear power plant in which the large dry containments are utilized. The containment must withstand the peak pressure and temperature caused by the LOCA. Containment is one of the major barriers against the release of radioactive substances to the environment. Therefore, it’s integrality during the LOCA must be ensured. The analyses performed in this study are the main steam line breaks with 102% and 25% rated thermal power, and the pump suction rupture of the cold leg of Maanshan plant. Sensitivity studies are also presented. GOTHIC is used for the containment analyses, and the blowdown mass and energy release data provided by the final safety analysis report (FSAR) of Maanshan plant are used as the boundary conditions. Short-term analyses for the pressure and temperature responses of the Maanshan’s large dry containment are performed in this study. In conclusions, the calculated results of the GOTHIC analyses are consistent with the FSAR results. The peak values of pressure and temperature are lower than the design values during the DBA LOCAs. The containment integrity during LOCA can be maintained.