Methods and instrumentation for measurement of radioactive waste

Full text: According to nuclear legislation of Ukraine radioactive waste (RAW) by acceptance for disposal (storage), data about radioisotope contents of waste, specific and total activity of each important radionuclide have to be noted into Raw index card for the purpose of its certification. New requirements stimulate the elaboration of methods and spectrometric devices for certification of RAW, which can ensure reliability and necessary accuracy of the values being measured. The report represents a survey of methods for determination of radionuclide contents and specific activity of RAW. The methods are based on measurement of exposure rate on the surface of RAW container or package and on analysis of gamma spectra from volumetric sources. A method of calibration of gamma-spectrometers for determination of specific activity of RAW developed by the authors is offered. The method is suitable for scintillation and semiconductor detectors. Calibration coefficients are got in laboratory conditions using point standard sources, which are later used for software calculation of specific activity of radionuclides in RAW. Material and density of RAW matter, dimensions and material of container or package are also taken into account by calculation. The method is tested in real conditions on Rivnenska NPP. A problem of application of spectrometry equipment for RAW certification is considered, as well as software, which is used for acquisition and analysis of gamma-spectra. (author)