Potential radionuclide release rates from marine reactors dumped in the Kara Sea

The largest inventory of radioactive materials dumped in the Kara Sea by the former Soviet Union comes from the spent nuclear fuel (SNF) of seven marine reactors, the 1994 inventory of which made a total of approximately 4.7 PBq. In progressing its work for the International Arctic Seas Assessment Project (IASAP), under the auspices of the International Atomic Energy Agency (IAEA), the IASAP Source Term Working Group has developed a number of simple computer models to predict the potential release patterns of radionuclides into the Kara Sea from the SNF and activated components dumped within the marine reactors. These models are based on the present and future conditions of the barrier materials and their configuration within the dumped objects. They account for progressive corrosion of the outer and inner steel barriers, breakdown of the organic fillers, and degradation and degradation and leaching from the SNFs. Annual release rates are predicted to beyond 5000 years into the future.