National Physical Laboratory

The UK's first decommissioned nuclear power plant

NPL contributed to the decommissioning of the Windscale Advanced Gas-cooled reactor (WAGR) by characterising waste so that it could be processed and disposed of accordingly.

The Windscale Advanced Gas-Cooled Reactor (Image courtesy of Sellafield Ltd)
The Windscale Advanced Gas-Cooled Reactor
(image courtesy of Sellafield Ltd)

The WAGR was built in the early 1960s and over its operational lifespan produced around 3,257,500 MWh of electricity.

The final stage in the decommissioning process finished at the end of May 2011 with the removal of the outer membrane from the reactor's bioshield - a concrete structure designed to keep radiation at safe levels for workers at the plant.

The United Kingdom Atomic Energy Authority (UKAEA) decided to decommission the reactor in 1981 in order to develop and demonstrate the knowledge, methodology and skills required to undertake such a task.

NPL scientists analysed concrete samples taken from various depths in the reactor shield wall so that the concrete could be properly assigned as either free release material, very low level waste, low level waste or intermediate level waste.

This work involved some novel measurements of nuclides that are normally not determined (59Ni and 93Mo) and led to the production of a standardised concrete reference material. This reference material will allow others to analyse their own samples and process radioactive waste accordingly in the future.

The project was originally instigated as a national demonstration exercise and NPL has developed new skills and materials that can be used in the future safe and sustainable decommissioning of the UK's ageing nuclear reactors.

Find out more about NPL's work on Radioactivity

Last Updated: 16 Jan 2019
Created: 26 Jul 2011


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