O. V. Mykhailov, V. O. Krasnov, V. M. Bezmylov
Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, 36a, Kirova str., Chornobyl, 07270, Ukraine
Brief review of the most well-known analytical and methodological materials devoted to the theory and practice in characterization of radioactive waste (RAW) generated at NPPs is presented. The basic principles of method for building scaling factors (SF) and the main features of SF application in technological chain of RAW management are disclosed. It was demonstrated that the basis that allows using the SF methodology is the availability of functional relationships between the activities of various radionuclides, which are simultaneously accumulated during reactor campaign and contamination of various materials. In the course of special investigation, it is needed as follows: to take a representative sample of waste from each stream of materials subject to radiation monitoring; in the laboratory to determine the content of all radionuclides to be certified; when using the methods of statistical data analysis, to identify the key nuclides (KN) and calculate the SF average values, which make it possible, based on the results of gamma-spectrometry of KN content, to estimate alpha and beta-emitting radionuclide activities in RAW packages, whose measurement demands high material costs and time (for DTM – difficult to measure radionuclides). An illustration of impact of different factors and mechanisms, which form DTM nuclides and KN content ratio in solid waste characteristic of RBMK-type reactors, is delivered. The basic requirements and procedures, which are to be reflected in the method to characterize solid RAW from Chornobyl NPP for DTM radionuclides certification using the SF, are determined.
Keywords: nuclear power plants, radioactive waste, characterization, scaling factors, key nuclides, difficult to measure radionuclide, correlation factor.
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