The effects of alternative ceramic fuels on the US-APWR nuclear power plant operational time

The Burn-Up enlargement is one of the most important issues in the nuclear reactor core fuel management. In this regards in recent years some reactor design companies have focused on the reactor cycle length enlargement. An enlarged core cycle length, results an increased fuel burn up which directly leads to low electricity costs and more efficiency. One of the promising issues is to change the chemical state of fuel that is on the agenda of the Mitsubishi Company as US-APWR nuclear reactor designer. In the present study, the effects of other commercial ceramic fuels such as UN, UC, and UN¹⁵ instead of conventional UO₂ fuel, on the light water reactor core has been studied. In this regard, a US-APWR fuel assembly is modeled using MCNPX2.6 by considering the periodic boundary condition. It was found that the use of UC and UN¹⁵ instead of UO₂ has a deep influence on cycle length such that the power plant operational time increased by a factor of 1.5 that is quite economically beneficial. On the other hand since the thermal conductivity of these alternative fuels are six times greater than UO₂, the thermal-hydraulic analysis of candidate fuels leads to outstanding results.