Burnup extension of the Fixed Bed Nuclear Reactor using alternative fuels

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 UO2/Reactor grade-PuO2; UO2/weapon grade-PuO2 and of UO2/MAO2 that would result in the similar initial value of keff as that of UO2, the original fuel of FBNR. Fuel component has been varied from 1% to 100%. The fuel compositions have been obtained with UO2: ① 35% RG-Pu O2; ② 19% WG-Pu O2; ③ 50% MAO2. After that, keff, burnup and operation time values of the fuels were compared. The temporal variation of the criticality keff 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-PuO2/UO2; weapon grade-PuO2/UO2 and MAO2/UO2 starts by keff = 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 MW D/T, respectively. On that way, the hazardous nuclear waste product can be transmuted as well as utilized as fuel.