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Reprocessing

Discover how reprocessing can recover valuable materials from spent fuel and reduce highly active waste.

What is reprocessing?

In a closed fuel cycle, Reprocessing is used to extract fissile isotopes from the spent fuel.

This is possible because only ~ ¹/₃ of ²³⁵U is used and some ²³⁸U is converted to ²³⁹Pu; therefore the spent fuel can be reprocessed to extract fissile ²³⁵U and ²³⁹Pu, which can then be remanufactured into nuclear fuel rods.

How is reprocessing of spent nuclear fuel carried out?

Reprocessing is usually via the PUREX Process (Plutonium and Uranium Reduction EXtraction), the only method currently in commercial use around the world. Irrespective of the process chosen, the result is that the uranium (U, 96%), plutonium (Pu, 1%) and fission fragments (3%) are separated from one another.

Uranium-235

Uranium-235 is then processed at a conversion plant and can be used for uranium-based reactor fuel.

Plutonium-239 & Uranium-238

Plutonium-239 can be combined with Uranium-238 to generate Mixed Oxide Fuel (MOX) – used in PWRs outside the UK or in fast breeder reactors.

Fission Fragments

The fission fragments are High Level Waste (HLW, mostly Np, Am, Cm) and constitute circa 3% of the volume – these are interim stored, pending final disposal in a Geological Disposal Facility (GDF).

What is the PUREX Process?

PUREX is an acronym for Plutonium and Uranium Reduction EXtraction, a well-established chemical process for reprocessing of spent nuclear fuel.

The process involves first shearing fuel rod’s internals from its cladding, before dissolving the spent nuclear fuel in hot, concentrated nitric acid. Solvent extraction in Tributyl Phosphate (TBP) and Odourless Kerosene (OK) can then be used to separate the fission fragments (minor actinide species), uranium (U) and plutonium (Pu).

Where does reprocessing take place?

France, Russia and Japan are world-leaders in commercial reprocessing capacity. In total, of more than 400,000 tonnes of spent fuel generated worldwide, approximately 30% has been reprocessed.

However, as of 2022, the UK no longer reprocesses any spent nuclear fuel:

What happens in the UK?

Reprocessing previously took place in the UK at the Sellafield site (and Dounreay) but is no longer economically viable, due to the relatively low cost of uranium and lack of international custom, particularly following the Fukushima incident.

UK Nuclear Sites

Find out where nuclear sites are located around the UK.

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Is there a history of reprocessing in the UK?

First Generation Reprocessing Plant

Built to extract plutonium in support of the UK’s nuclear weapons programme, the First Generation Reprocessing Plant (at the Sellafield site) used the BUTEX process – a forerunner to the more efficient PUREX process. The plant operated between 1951 and 1964.

Mangox Reprocessing Plant

Magnox Reprocessing Plant, at the Sellafield site, closed on 17 July 2022; this coincided with the conclusion of the UK’s Magnox Operating Plan (MOP) – a six-decade plan for the operation and fuel cycle of the country’s first generation Magnox reactor fleet. Between 1964 and 2022, the plant successfully reprocessed the vast majority of spent Magnox fuel from the UK’s reactor fleet. The final two Magnox reactors to be defueled were Wylfa and Calder Hall.

THORP

ThORP (Thermal Oxide Reprocessing Plant), also at Sellafield, was commissioned in 1994 and closed in 2018. The facility reprocessed uranium dioxide fuel (UO₂) from the UK’s Advanced Gas-Cooled Reactors (AGRs), in addition to UO₂ and Mixed Oxide (MOx) fuel from international customers (predominantly Japan). Since 2018, spent AGR fuel is interim stored in ThORP Receipt & Storage (TR&S) at the Sellafield site, pending final disposal in a Geological Disposal Facility (GDF). This storage does not eliminate the option to reprocess this fuel in the future, should the political and economic climate change.

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Reprocessing

What is reprocessing?