Thorium-plutonium (Th,Pu) oxide fuels will provide an evolutionary way tosimultaneously reduce plutonium volumes and capture energy from this material. In this work wecompare the neutronic properties of Th,Pu-fuel and MOX fuel with different Pu isotope vectors.For these studies, burn-up simulations are performed for a regular MOX PWR fuel assembly andfor a thorium-plutonium PWR fuel assembly of the same geometry. The neutronic properties andperformance of the assemblies are investigated by lattice calculations using CASMO-5. Theplutonium content of the two fuel types is chosen so that the same total energy release per fuelassembly is achieved, which demanded a somewhat higher plutonium content in the thoriumplutoniumcase. The assemblies are then analyzed with regards to temperature coefficients,delayed neutron fractions, control rod and boron worths, coolant void reactivity (CVR) and decayheat. Overall, the results show that MOX and Th,Pu-fuel have fairly similar neutronic propertiesin existing PWRs. Th,Pu-fuel offers an advantage over MOX fuel with regards to CVR values andplutonium consumption. The conclusion is therefore that introducing Th,Pu-fuel would improvethese factors without imposing any major hurdles from a reactor physics point of view
