Temperature Distribution Inside Fresh Fuel Pins of Pressure Tube Supercritical Water Cooled Reactor

Abstract

The radial temperature profile for ThO2PuO2 freshfuel pins of the pressuretube supercriticalwatercooled reactor (PTSCWR) is simulated for two different radial distributions of the ThO2 and PuO2, one whereby the ThO2 and PuO2 are mixed together in a single, homogeneous region, and another one whereby ThO2 and PuO2 occupy separate radial regions inside the pin with the ThO2 occupying the inner region. The radial power density in each fuel pin is calculated from a latticelevel transport calculation using the lattice code DRAGON and is used together with the temperaturedependent fuel thermal conductivity to analytically solve the heat conduction equation and thus calculate the temperature profile inside the fuel pin. Results indicate that, for fresh fuel, the centerline temperature is much lower for a tworegion pin than for a singleregion pin, and thus, the risk of fuel melting is greatly reduced for the tworegion fuel compared to the singleregion fuel.