Abstract: Noble gas is a kind of radioactive material produced in nuclear fission processes of a nuclear power unit. Nevertheless such radiation source term and its exposure risk to workers of nuclear power plants during specific conditions has been neglected, due to its physical form and charachteristics as well as the difficulties of exposure dose measurement technology. This paper calls for attention to the professional radiation staffs of nuclear power plants to make further efforts to identify those specific radiation risks existed inside the nuclear power plant and then to control and reduce the source terms and their exposure risks.

Key words: radioactive noble gases, reactor building, source term identification, specific unit condition, source term control