NPP Radwaste Activity Determination by the Correlation Method

A radwaste radiation-monitoring methodology based on correlations established between the activity of radionuclides and making it possible to determine the activity of hard-to-detect radionuclides (³H, ¹⁴C, ⁶³Ni, ⁹⁰Sr, ²³⁸U, ^{238, 239, 240}Pu, and others) in waste lots was investigated. An algorithm for compiling a list of radionuclides monitored during certification of the wastes, which is based on criteria for the wastes being radioactive and their classification, and requirements for the intermediate storage time and the half-life of radionuclides, and an algorithm for establishing the correlations between the specific activity of the reference and hard-to-detect radionuclides were developed in order to implement the methodology. The application of the criterion and algorithm to the wastes at the Novovoronezh NPP made it possible to compile a list of monitored radionuclides that agrees with the national operator in terms of handling radwastes and to establish the correlations between the activity of individual radionuclides and confirm the applicability of the methodology to radwaste from NPPs.