Magnox Reprocessing

The Magnox Reprocessing plant at Sellafield reprocesses spent nuclear fuel from Magnox nuclear power stations across the country – including Sellafield’s Calder Hall station.

Magnox Reprocessing
Magnox Reprocessing


There are two nuclear fuel reprocessing plants at Sellafield. The Thermal Oxide Reprocessing Plant (Thorp) deals with fuel from British Advanced Gas-cooled Reactors (AGR) and Light Water Reactors (LWR) from around the world. For more information please see the Thorp section of the Sellafield Plan.

The second deals with Magnox fuel from Britain’s early nuclear reactors, like the ones which were used at Calder Hall power station at Sellafield which ceased generation in March 2003.

Before it can be reprocessed, irradiated Magnox fuel must be stored for at least 180 days in ponds to allow short lived fission products to decay. Following transport to Sellafield and a period of further storage the cladding (magnesium alloy) is removed from the uranium bar.

This all happens in the Fuel Handling Plant. The fuel is then transferred to the Magnox Reprocessing Plant.

The main Magnox Reprocessing plant began operations in 1964. 

The reprocessing operation within Magnox Reprocessing entails the dissolution of the irradiated uranium rods in nitric acid. The solution is then subject to a series of solvent extraction processes in which the uranium, plutonium and fission products are separated into three different streams. 

These streams are directed to other plants at Sellafield where the uranium, in the form of uranium nitrate, is converted to solid uranium trioxide; the plutonium, in the form of plutonium nitrate, is converted to plutonium oxide, and the fission products, in the form of nitric liquor, are stored in Highly Active Storage Tanks before being vitrified. For more information on the vitrification process please see the HAL Workstream section of the Sellafield Plan.

The Magnox Reprocessing Plant at Sellafield is the only one of its kind in the UK. As such the plant has a vital role in supporting risk and hazard reduction operations across the Nuclear Decommissioning Authority’s estate by reprocessing fuel which is being retrieved from operating and closed Magnox power stations. This work is co-ordinated through the Magnox Operating Programme.

It will also support risk and hazard reduction at Sellafield by reprocessing the fuel which will be retrieved from the Calder Hall station on site.