Investigation of the Nuclear Inventories of High-Exposure PWR Mixed-Oxide Fuels with Multiple Recycling of Self-Generated Plutonium

Based on the use of the Joint Evaluated File (JEF-1) with the KARBUS burnup code system and subsequent KORIGEN code calculations, the characteristics of spent pressurized water reactor mixed-oxide (MOX) fuels are analyzed. Actinide masses, decay heat, radioactivities, and radiation are discussed for burnups of 40 to 55 GWd/tonne HM for MOX fuels based on natural uranium and on uranium tailings. Multiple plutonium recycling is considered at a burnup of 50 GWd/tonne HM. The results are compared with earlier data at a burnup of 33 GWd/tonne HM. The high-exposure MOX fuels are found to contain large amounts of the heat-releasing and radiating nuclides, ²³⁸Pu and ²⁴⁴Cm. The ²³⁸Pu in the plutonium, which is to be used for the fabrication of fuel elements from recycled MOX, requires special shielding or a change from glove box techniques to an automated treatment.