The measure on mitigating hydrogen risk during LOCA accident in nuclear power plant

Abstract Since there is a large empty space in PWR containment which has strong pressure bearing capability, it’s generally considered that there is no overall risk of hydrogen. However, the complex internal structure makes hydrogen easy to accumulate, burn or even explode in local compartment. Therefore, when LB-LOCA with gravity injection failure happens, there may be a more serious risk of local hydrogen. GASFLOW, a three-dimensional computational fluid dynamics code, is used to study the measure on mitigating hydrogen risk. During the simulation, a steam injection device is arranged in the PZR compartment. When the accident occurs, steam is injected into the PZR compartment during the pre-set stages. By comparing the hydrogen risks in different situations, it could be found that steam injection in local space can reduce the hydrogen risk locally. The method combining steam injection device with PARs is an effective measure to mitigate the risk of hydrogen.