High Quality Content by WIKIPEDIA articles! The Thermal Oxide Reprocessing Plant, or THORP, is a nuclear fuel reprocessing plant at Sellafield in Cumbria, England. THORP is owned by the Nuclear Decommissioning Authority and operated by Sellafield Ltd (which is the site licensee company). Spent nuclear fuel from nuclear reactors is reprocessed to separate the 96% uranium and the 1% plutonium, which can be reused in mixed oxide fuel, from the 3% radioactive wastes, which are treated and stored at the plant. The uranium is then made available for customers to be manufactured into new fuel.