Burnup extension of the Fixed Bed Nuclear Reactor using alternative fuels

摘要

Time evolution of criticality and burn up grades of the Fixed Bed Nuclear Reactor (FBNR) are investigated using alternative fuels. Neutron transport calculations are performed by using XSDRNPM/SCALE 5 codes. Firstly, the calculations were performed to search the optimum compositions of UO_2/Reactorgrade-PuO_2; UO_2/weapon grade-PuO_2 and of UO_2/MAO_2 that would result in the similar initial value of k_(eff) as that of UO_2, the original fuel of FBNR. Fuel component has been varied from 1% to 100%. The fuel compositions have been obtained with UO_2: ① 35% RG-Pu O_2; ②19% WG-Pu O_2; ③ 50% MAO_2. After that, k_(eff), burnup and operation time values of the fuels were compared. The temporal variation of the criticality k_(eff) and the burn-up values of the reactor have been calculated by full power operation for a period of 18 years. The criticality in compositions of Reactor grade-PuO_2/UO_2; weapon grade-PuO_2/UO_2 and MAO_2/UO_2 starts by k_(eff)= 1.2742, 1.2726 and 1.2783 for the fuels compositions, respectively. These mixed fuels would allow full power reactor operation for ≥ 14 years and burn up grade can reach ~ 104,646, ~101,990 and ~80,798 MWD/T, respectively. On that way, the hazardous nuclear waste product can be transmuted as well as utilized as fuel.