A statistical evaluation of the liquid effluent release from NPP based on analytical methods with low detection limits

Eight liquid effluent samples from nuclear power plants (NPP) were analyzed for 63 Ni, 131 I, and gamma radionuclides using methods with low detection limits. The sum of the radionuclides activity concentrations of the effluent samples from NPPs A and B were closely lower than the operator’s results with a maximum of decreasing to 29%, while from NPP C were much lower with a maximum of decreasing to 5%. The unlisted radionuclides account for 5.0–889%. It was indicated that the statistics method of the discharge amount could be established based on a regular investigation of the radionuclide characteristics based on analytical methods with low limits of detection.