Methods for determining the amount of fissile materials in containers with liquid radioactive waste have been developed. The concentration of the sum of fissile materials (uranium-235 and plutonium-239) was determined by the method of plastic track detectors. This method is adapted to highly saline waters and bottom sediments. The contribution of plutonium-239 to the sum of fissile materials was determined by the radiochemical method. The methods were used to solve nuclear safety problems during decommissioning of NPPs.
The radiochemical procedures of the extraction of the nuclides U, Pu, Am and Cm and the alpha - spectrometric method of their registration have been developed to analyze actinides in the liquid radioactive waste with a high content of salts and organic impurities. The plastic track detector method has been developed to determine micro concentrations of the fissile materials U-235 and Pu-239. The above methods have been adapted to be applicable for the liquid radioactive waste analysis.