An analysis on the breeding capability and safety related parameters of advanced fast reactor fuels using recent cross-section set

This study focuses on the evaluation of breeding capability as well as safety related neutronic parameters of advanced fast reactor fuels which comprises of fissile–fertile combination of metal, oxide, carbide and nitride, using the recent neutron cross-section set ENDF/B-VI.7. Sodium cooled fast breeder reactor similar to prototype Fast Breeder Reactor (PFBR) is used to evaluate the performance of various fuel types involving fissile isotopes of 233U and Pu and fertile isotopes of Th and 238U. The analysis is restricted to a comparison of neutronic parameters of a fresh core and does not take into account the effects of burnup and fission products. The breeding potential of the fuels are also compared with European cross-section set JEFF-3.1. The breeding ratio of advanced fuels evaluated with ENDF/B-VI.7 and JEFF-3.1 was found to be in good agreement. From this study, it is found that Th–233U combination for almost all fuel types with the present geometry and composition gives a lower breeding ratio value. Safety neutronic parameters such as effective delayed neutron fraction, Doppler defect and sodium void reactivity were also computed. In terms of breeding potential and safety neutronic parameters, the performance of Th–Pu system especially the metal fuel type can be a better option for future large fast reactors. The large negative Doppler feedback along with a negative sodium void reactivity for metal and hybrid combinations of Th–233U system makes it an attractive fuel cycle option even though there is a penalty over its breeding capability.