Abstract: Hydrogen containing gaseous waste from primary loop consists of hydrogen and radionuclides. Radionuclides include ⁸⁵Kr, ^85mKr, ⁸⁸Kr, ¹³³Xe, and ¹³⁵Xe, as well as small amount of ¹³¹I, ¹³²I, ¹³³I, ¹³⁵I, ¹³²Te etc. Due to shortage of decay box capacity, the purge operation of the reactor coolant system and the overhaul process are affected and hydrogen leakage risk is also created. Pressurized storage decay treatment process which has been widely used to treat hydrogenous gaseous radioactive waste in M310 NPPs needs to be modified and optimized. In this paper, based on hydrogen sources, through the investigation of various normal operating conditions, operating specifications and standards, the gas emission quantity and components ratio were analyzed. We concluded that the key factors are the purge operation of volume control tank and the reactor coolant system. Peak gas flow and total volume, and the volume ratio of hydrogen are shown through the Calculation. Reasonable capacities of different processes are proposed at last, avoiding economic waste caused by excessive redundancy.

Key words: NPP, hydrogen-containing gas, capacity analysis, optimization of process