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ONR completes first ever full decommissioning of UK reactor site under modern regulatory controls

The Imperial College Reactor Centre (ICRC) has become the first reactor site to be fully decommissioned in UK nuclear history under modern regulatory controls.

The site was delicensed by the Office for Nuclear Regulation (ONR) following many years of work to defuel and then decommission the site in Ascot after the shutdown of the consort research reactor in 2012.

Part of Imperial College London, ICRC has now been assessed by ONR as posing no danger to the public, and no longer requires ONR regulatory controls.

It is the first UK reactor site to be completely delicensed under modern regulatory controls, in April 2022.

The Imperial centre is only the third UK reactor site in history to be fully decommissioned, and its land has now been returned for re-use.

ONR inspectors have studied the Silwood Park site’s final Environmental Management Plan in recent months and are content that the concluding decommissioning work, including asbestos surveillance and landscaping, has been completed.

As a result, ICRC is no longer subject to regulations under the Environmental Impact Assessment for Decommissioning Regulations (EIADR) 1999.

Ian Phillips, ONR’s Head of Safety Regulation for Decommissioning, Fuel and Waste sites, said: “This is a highly significant achievement and milestone in UK nuclear decommissioning history and testament to all the hard work that has been put in at the Imperial College Reactor Centre to reach this final end state.

“It represents the conclusion of a 65 year journey for the ICRC which can now be recognised as the country’s first ever fully decommissioned reactor site under modern regulatory controls - a fantastic accomplishment.

“Our regulatory oversight ensured that all necessary conditions involved in the defueling, decommissioning, demolition, and delicensing process were realised to meet the high standards we demand in order to maintain the ongoing safety of workers and the public.”

The ICRC was constructed in the early 1960s and the consort reactor achieved criticality in 1965.

It was a small research reactor (100 kW) which was moderated, cooled, reflected, and partially shielded by light water.

Following a significant decline in the volume of research conducted in the facility, the reactor started being shut down 13 years ago.

Defueling was completed in 2014 and 31 fuel elements were removed and transported to Sellafield in Cumbria for interim storage pending reprocessing.

Decommissioning of the reactor and surrounding bioshield was completed in February 2020, and the demolition of all building structures, removal of the base slab and below ground services finished in April 2021.

Trevor Chambers, former Head of the Imperial College Reactor Centre, said: “Imperial College London is indebted to the Reactor Centre team who provided deep technical and operational oversight throughout the project, as well as support contractors and the site Nuclear Safety Committee for their dedication.

“Releasing the site from regulatory control has created a recreational space at the heart of Imperial’s Silwood Park eco-campus, which may now be used without restriction by staff and students at the forefront of biodiversity science and policy.

“Imperial continues to look to the future, with our Centre for Nuclear Engineering providing research and study opportunities to meet the world’s growing energy needs while reducing carbon emissions.”

The Consort research reactor control desk, that still remains within the reception area.

Currently, ONR regulates 35 licensed nuclear sites in the UK.

You can find out more about how we regulate the decommissioning of sites and the Environmental Impact Assessment for Decommissioning Regulations (EIADR) 1999 on our website.