Windscale was historically a separate licensed site located on the Sellafield site. On 1 April 2008 the site licence for Windscale was transferred to Sellafield Ltd, integrating the Windscale and Sellafield sites. It comprises three reactors, two of which were shut down in 1957 and the third in 1981. Decommissioning activities began in the mid 1980s.
The Windscale Pile reactors were constructed to support the British Atomic programme. The Piles were the country’s first large scale nuclear reactors producing plutonium for the UK’s nuclear deterrent. Following a fire in Pile one in October 1957, both reactors were shut down. Phase 1 decommissioning started in the early 1980s and recent work has focused on carrying out intrusive survey work of the Pile 1 core and developing approaches to remove the fuel and isotopes from the fire damaged reactor.
In the late 1950s, Windscale was chosen as the setting for a new reactor which was to explore the potential of high pressure and temperature gas-cooled reactor fuel and components. The Windscale Advanced Gas-cooled Reactor (WAGR) was constructed between 1957 and 1961 and operated successfully. WAGR was built to study and prove in service the performance of gas-cooled fuel elements suitable for a commercial reactor. It also served as a test bed for the development of advanced fuel and other components and provided operational experience of power production. WAGR was the forerunner of a family of 14 reactors on seven sites built to generate cheaper and more efficient electricity in the UK.
WAGR has been a decommissioning demonstration project, showing that a full sized reactor can be decommissioned safely, cost-effectively and in an environmentally acceptable manner. The decommissioning of the reactor within WAGR was safely completed in May 2011, significantly reducing the hazard associated with the iconic ‘golf ball’ structure.