The Nuclear Decommissioning Authority

15 December 2010

Berkeley nuclear site has today become the first commercial power station in the UK to seal up its reactors in a major decommissioning milestone.The two Magnox reactor buildings will be placed in a passive state, known as Safestore, and monitored and maintained until the site, near Bristol, is completely cleared in about 65 years' time.

NDA owns the site, which is currently being decommissioned by Magnox South Ltd, a company owned by EnergySolutions.    

Berkeley Power Station was the first built in the UK to produce electricity commercially and its two natural uranium-fuelled reactors came into service in 1962. The two reactors supplied four turbo generators with a total output of 276 megawatts (MW) of electricity, until reactor two was shut down in October 1988 and reactor one in March 1989.  The total power supplied over the operating life of the plant was 40 terawatt hours (Twh).       

Following its closure 20 years ago, Berkeley site has led the way as the first nuclear power station in the UK to undergo extensive decommissioning, sharing innovation and best practice across a range of projects.   

To progress both reactors into Safestore is yet another first for Berkeley, as well as a first for the NDA and a first for the UK nuclear industry.  

Sara Johnston, the NDA's Head of Programme, said:

"This is a hugely significant achievement, not just for the site but for the UK nuclear industry as a whole, demonstrating the progress being made in decommissioning. Reaching Safestore at Berkeley will also provide valuable knowledge and expertise that will assist with taking the remaining Magnox reactors into Care and Maintenance."  

Reaching Safestore is a huge milestone in the preparations needed to get to the final long-term Care and Maintenance phase. This is when all major decommissioning work is complete, leaving only a waste store and the reactors on site to be monitored until final dismantling planned to start in 2074, when the deep geological disposal facility (GDF) is expected to be operational.    

Preparations for Care and Maintenance began following the defuelling of the 84,877 fuel elements between 1989 -1992, which resulted in 99 per cent of the radioactivity being removed from the site.  

The main focus of work for the Safestore project has been to streamline the reactors leaving only the reactor vessel and core, where radioactivity demands storage within the Safestore phase of their lifetime.  The programme of extensive work first began in 1993 with the decommissioning of both reactors' eight primary gas circuits.   

Tackling the complex legacy intermediate level waste in Berkeley's vaults, generated during its history as a power station and as a research laboratory, is the next and final challenge on the journey into Care and Maintenance.