Isotopic inventories of the discharged T37 fuel bundles

The paper describes studies that have been undertaken to analyse the mass inventory of the thorium-uranium mixed oxide fuel removed from the standard CANDU 6 reactor. The analysed T37 fuel bundle configuration is based on thorium and low enriched uranium (LEU) oxide, considering the ThO₂ ratio of 100% in the central pin, 60% in the inner and intermediate rings and 80% in the outer ring. The ²³⁵U enrichment has been varied in the radial direction from 6% to 10%. The study focuses on identifying optimal thorium - uranium combination from the viewpoint of reducing the content of plutonium and highly radiotoxic minor actinides content the spent fuel accumulated in 30 years operating reactor. The lattice simulations have been performed using the Continuous-energy Monte Carlo Reactor Physics Burn-up Calculation Code - SERPENT 2, version 2.1.30. In order to perform the depletion calculations, the ACE format cross section library JEFF-3.1.1 have been used. (author).