Radiation safety assessment and development of environmental radiation monitoring technology

The Periodic Safety Review(PSR) of the existing nuclear power plants is required every ten years according to the recently revised atomic energy acts. The PSR of Kori unit 1 and Wolsong unit 1 that have been operating more than ten years is ongoing to comply the regulations. This research project started to develop the techniques necessary for the PSR. The project developed the following four techniques at the first stage for the environmental assessment of the existing plants. 1) Establishment of the assessment technology for contamination and accumulation trends of radionuclides, 2) alarm point setting of environmental radiation monitoring system, 3) Development of Radiation Safety Evaluation Factor for Korean NPP, and 4) the evaluation of radiation monitoring system performance and set-up of alarm/warn set point. A dynamic compartment model to derive a relationship between the release rates of gas phase radionuclides and the concentrations in the environmental samples. The model was validated by comparing the result with the samples. The results of the research will be used in the Periodic Safety Review of the nuclear power plants in operation.