Research by the UK National Laboratory suggests that the small modular reactor (SMR) designed by NuScale Nuclear has the capability of using mixed uranium-plutonium oxide (MOX) fuel in addition to conventional light water reactor fuel. According to Oregon-based NuScale, this supports the suitability of its SMR technology for the effective disposition of plutonium.

The UK study evaluated scenarios with partial and full-core loading of (MOX) fuel and concluded that MOX could be used in the NuScale core with minimal effect on the reactor’s design and operation. The study also demonstrated that a 12-module NuScale plant with 100% MOX cores could consume a 100-metric-ton stockpile of discharged plutonium in roughly 40 years. During that stretch it also would generate approximately 200 million megawatt-hours of carbon-free electricity.

Plutonium reprocessing into MOX fuel for civil nuclear reactors has been realized in several countries, including France, Japan, Belgium, Switzerland and Germany. The primary advantage of using MOX fuel is to use the energy content of plutonium and degrade its isotopic composition making it less attractive from a proliferation viewpoint. The process also helps to improve fuel resource use by reducing the demand for enriched uranium.

The UK holds one of the world's largest stockpiles of civil plutonium material, with more than 100 metric tons managed at Sellafield in North West England. However, the UK Government has said that this stockpile needs to be addressed either through re-use or disposal.