MOX fuel mixed with graphite as a fuel for use in Generation IV nuclear reactor using the Monte Carlo method

A new nuclear fuel formed of 50% of MOX and 50% of graphite (carbon) is proposed to be used in Generation IV nuclear reactors (in particular the ALLEGRO reactor) with the best neutronic and thermal-hydraulic characteristics. The neutronic calculations are made using the MALBRN computer system. Calculations are made for ALLEGRO with 400/850°C inlet/outlet coolant temperatures. The fuel is shown to be superior to the other carbide and nitride fuels that are other candidates to be used in this type of reactors. The temperature drops on the fuel reach about 16°C for the new fuel in comparison with 188°C, 18.1°C, 22.6°C for the pure MOX, the nitride and carbide fuels, respectively. The thermodynamic efficiency for the coolant thermodynamic cycle that can be reached with this fuel can potentially exceed 64% for an outlet coolant temperature of about 1500°C.