Assessment of radiation risks from spent nuclear fuel depending on composition of radionuclides and radiation dose distribution in organs

The article presents the method for assessing radiation risks from spent nuclear fuel depending on the radionuclides composition and radiation doses distribution in organs. The method can be used for optimizing management of spent fuel in view of lowering the fuel storage period in which the risk from spent nuclear fuel will equal that from natural uranium before its dumping. Coefficients of radiation-associated lifetime attributable risks of developing cancer (LAR´106/mSv) for men were calculated. Risks of developing cancer of different sites as a result of internal irradiation by radionuclides in BREST-300 (300 MWe) and WWER-1000 spent nuclear fuel were assessed. Table of risk coefficients was drawn up. Dynamics of changing relative radiation risks (in relation to the natural uranium) for different tumor sites as a result of exposure to radionuclides of BREST-300 and WWER-1000 spent nuclear fuel was calculated. Practical conclusion resulted from the study is as follows: for dumping spent nuclear fuel, when health risks from nuclear fuel equal risks from natural uranium. Plutonium isotopes should be separated from the fuel. The time of radiological equivalence, when above mentioned risks equal, may depend on uncertainties in calculating LARs, however to determine the time special simulated mathematical models should be developed.