Effluent gases from nuclear power plants

Radioactive effluents from nuclear power plants derive from nuclear fission products of nuclear fuels and activated products of some materials in the reactor water due to neutron irradiation in the reactor cores. Effluent gases with radioactivity must be managed according to a strict regulation as gaseous wastes and the amount of released radioactivity shall be reduced as low as reasonably achievable with off-gas systems installed. Mechanism of production of radioactivity sources, release paths of gaseous wastes with off-gas systems, radiation monitoring of off-gases and stack, and holdup systems using activated carbons to reduce the amount of released radioactivity were introduced with operating results. (T. Tanaka)