The United States and the Russian Federation have agreed to dispose of their excess weapons-grade plutonium, with consuming the material as nuclear fuel in light water reactors for electricity generation often discussed as the best option. Lightbridge Corporation has several thermal reactor fuel designs that offer very high burnups, in the range of 21 at. % or approximately 190 900 MWd/tonne of heavy metal, which make them well suited for consuming excess weapons-grade plutonium. MCNP6.2 computer simulations were performed to quantify the mass of plutonium consumed in a Lightbridge-designed fuel rod compared to traditional mixed-oxide (MOX) fuel, as well as the attractiveness of the plutonium in the used fuel for weapons purposes. The results of these simulations show that the Lightbridge plutonium disposition fuel variant consumes approximately 5.5 times more plutonium per fuel rod than MOX fuel and that the material attractiveness of the Lightbridge-used plutonium is noticeably less than that of MOX fuel.