AN ESTIMATE OF THE AMOUNTS OF 235U, 239PU AND THE MATERIAL ATTRACTIVENESS IN NAVAL IRRADIATED NUCLEAR FUEL FROM THE FIRST AND SECOND GENERATION OF RUSSIAN SUBMARINES

Calculations of the content of 235U, 239Pu, fission products and actinides in irradiated nuclear fuel from Russian submarines of first and second generation, show that from 1 to 5 kg of 239Pu have been produced in a fully burned reactor core. Such quantities of 239Pu in these small cores, with a possible total fuel volume less than 0.15 m3 and less than 10 kg of mass in one fuel assembly, do represent a proliferation risk. To evaluate if the spent fuel is selfprotective, the inventory of both fission products (137Cs and others), and build up actinides (241Am and others), have been calculated and considered. The results show that, after more than 30 years storage after decommissioning, the fuel assembly can not be regarded as being selfprotected. However, irradiated fuel from first and second generation Russian submarines is not a priority proliferation concern, because of the relatively low initial enrichment in 235U compared to other Russian naval fuel, and because the enrichment decreases substantially as the fuel is burned.