What is one of the main uses of plutonium recovered from reprocessing spent fuel?

The primary use of plutonium recovered from the reprocessing of spent nuclear fuel is as mixed oxide (MOX) fuel. MOX fuel is a blend of plutonium and uranium oxides, which can be utilized in light water reactors and other types of nuclear reactors. This use not only helps in recycling plutonium but also reduces the amount of high-level waste that is generated from spent fuel. By incorporating plutonium into MOX fuel, nuclear power plants can utilize this material efficiently while providing a sustainable solution to managing nuclear waste.

The production and use of MOX fuel can help to decrease reliance on natural uranium resources and promote a more circular nuclear fuel cycle, where valuable materials are reused rather than discarded. The successful application of MOX fuel enhances the overall sustainability of nuclear power generation and aligns with efforts to minimize the environmental impact of nuclear waste.

Other options, such as storing plutonium indefinitely or converting it to high-level waste, do not contribute to resource recovery or utilization in a manner as effective as the use of MOX fuel. While plutonium can indeed be utilized in nuclear weapons, the context of the question focuses on its applications in civilian nuclear power.