CFD Analysis on Hydrogen Risk in Qinshan II NPP

The computational fluid dynamics code GASFLOW is applied to simulate the steam/hydrogen behavior inside the containment of Qinshan II NPP, installed with 22 Passive Automatic Recombiners （PAR）, during the first 7 000 seconds of a postulated surge line Large Break LOCA accident. The results imply that the structures remove large amount of heat from the containment atmosphere and that the pressure variation is controlled by the inventory of gas （mainly steam） and the temperature. Two typical flow patterns and hydro-gen strafication are found in the containment during the accident. The stable recombination capability of the given arrangement is about 20 g/s. The possibility of flame acceleration is indicated.