The insertion of reprocessed fuel spiked with thorium in a typical PWR fuel element considering (TRU-Th) cycle was simulated using different fissile materials that varied from 5.5% to 7.0%. The reprocessed fuels were obtained using the ORIGEN 2.1 code from a burned PWR standard fuel (33,000 MWd/tHM burned), with 3.1% of initial enrichment, which was remained in the cooling pool for five years and then reprocessed using UREX+ technique. The kinf, hardening spectrum and the fuel evolution during the burnup were evaluated. This study was performed using the SCALE 6.0
