Because the concept of a light water PWR plutonium burner has been examined for several decades, significant research into the neutronics and thermal hydraulics of possible designs has been performed. Whereas those designs covered mostly reactor grade plutonium in conventional UO_2 host material and zirconium alloy cladding, this paper examines PWR cores utilizing weapons-grade plutonium with a ThO_2 host and silicon carbide cladding. This cladding is likely to be composed of a composite structure that will require a greater cladding thickness. An approach which allows the same cladding outer diameter (9.5 mm) as with zirconium, while decreasing fuel pellet diameter (8.19 mm compared to 7.91 mm) is evaluated here. The cores developed achieve a burnup of 492 EFPD with an average fresh fuel composition with 6.0 to 7.5 weight percent of Pu. To deal with this high initial reactivity, three options were examined: gadolinium mixed within the fuel pellet, an enriched integral fuel burnable absorber (IFBA) fuel pellet coating, and enriched boron within the coolant. The behavior of these PuTh cores with SiC cladding is compared against a PuTh core with Zircaloy cladding.
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