The Nuclear Decommissioning Authority

 

Construction of Sellafield's iconic 'golf ball' in the 1960s paved the way for the UK's second generation of nuclear power stations which today provide around 15% of our electricity. Now, the safe decommissioning of this industrial-sized reactor, recently completed, marks a different kind of milestone as the NDA makes major inroads on its mission to clean up the nation's nuclear legacy.

More than 20 years of work, much of it carried out remotely in an atmosphere too radioactive for human access, reached a conclusion recently, when the final section of the Outer Ventilation Membrane was removed from the concrete radiation shield of the Windscale Advanced Gas Cooled Reactor known as WAGR.

Made safe, the outer sphere will remain in place as attention turns to higher-hazard projects, reflecting the NDA's commitment to prioritise spending on the most urgent issues across the estate. Monitoring and maintenance will be carried out until it is finally demolished.

Chris Halliwell, Head of Programme Delivery, Sellafield Remediation and Decommissioning Projects, said:

"This is a fantastic achievement and the culmination of many years work. It is a true demonstration of the UK's ability to fully decommission nuclear power stations in a safe, cost-effective manner."

The decision was taken, when WAGR closed in 1981, to use the reactor as a national demonstration project for the decommissioning that would be required in future years.

Early years were spent developing the strategy and techniques, designing components, modifying the structure and installing the equipment. In 1999, dismantling of the reactor core and pressure vessel was started. By then, the project team had completed all testing of the principal methods to be used – namely robots, or remotely operated equipment - for dismantling of the components, overcoming numerous challenges and working closely with the supply chain along the way. Innovative thinking was key and the team has built up a vast wealth of skills and experience that are already being deployed in other high-hazard projects, both at Sellafield and across the wider decommissioning estate.

 

Each step of the journey also had to be safe and compliant, meeting all the stringent requirements of legislation and the regulators. 

Peter Law, Windscale Senior Project Manager, said:

"The WAGR team should be immensely proud of their achievements. Completion of the reactor dismantling has required a great deal of technical ingenuity and persistence."

The Low Level Waste (LLW) has been packaged and consigned to the national Low Level Waste Repository near Drigg in Cumbria, while Intermediate Level Waste (ILW) has been encapsulated in purpose-built shielded concrete boxes which are held in nearby storage until a permanent disposal solution is available.

WAGR represented one of the major hazards at Sellafield, however, it is just one part of the complex decommissioning jigsaw at the site and the priority now is to focus on other facilities which also date from the early days of nuclear development in the UK.

Dr Ian Hudson, the NDA's Head of Programme for Sellafield, said:

"As we progress the clean-up mission, it is important that major milestones such as the successful completion of this phase of the overall decommissioning of WAGR are achieved as soon as possible.

"That's why I'm particularly pleased that the site has successfully concluded the decommissioning of the reactor itself."