Magnox decommissioning milestones

Several milestones have been reached in the decommissioning of the UK's fleet of Magnox nuclear power plants, including the completion of defuelling at Chapelcross and the removal of a transformer from the Oldbury site.

Several milestones have been reached in the decommissioning of the UK's fleet of Magnox nuclear power plants, including the completion of defuelling at Chapelcross and the removal of a transformer from the Oldbury site.

The last shipment of used fuel leaves Chapelcross (Image: Magnox)

The final shipment of used fuel from the UK's Chapelcross nuclear power plant has been sent for reprocessing at Sellafield, marking the end of a four-year operation to remove all fuel from the site.

Chapelcross in Scotland was one of the world's earliest nuclear power plants, with four 49 MWe Magnox units operating from 1959 and 1960 until 2004. Magnox Ltd, which manages the Chapelcross site on behalf of the Nuclear Decommissioning Authority, received approval from the Office of Nuclear Regulation in July 2008 to start defueling the Chapelcross site.

The first shipment of fuel to Sellafield left Chapelcross in April 2009. Magnox announced that the final flask containing used fuel from Chapelcross left the site on 26 February. This landmark was reached four months ahead of the original target to remove all the used fuel from the site by June 2013 and six weeks ahead of a challenge later set by the NDA to complete fuel removal by March.

Asbestos removal

Magnox Ltd has also completed a ten-year project to remove over 2100 tonnes of asbestos from the Hinkley Point A site in Somerset. The turbine hall alone contained almost 400 tonnes of asbestos.

Magnox described the asbestos as "the largest non-radiological hazard on the site."

Site director Lee Talbot said, "It's been a huge task to methodically clear the site of this historic hazard but we are extremely pleased to have reached a safe conclusion to this milestone project."

In total 38,075 fuel elements have been transported from Chapelcross to Sellafield in 257 flask shipments over the past four years. This, Magnox said, has removed 99% of the radioactivity from the site. It noted that following verification work over the next few months, the Chapelcross site will be declared completely free of nuclear fuel for the first time in more than 50 years.

NDA chief operating officer Mark Lesinski commented, "This is a huge achievement for Chapelcross and for the decommissioning and clean-up program in the UK."

Although all the fuel has only just been removed from the site, various decommissioning work has already been conducted at Chapelcross since the plant stopped operating. This includes the demolition of the plant's cooling towers in May 2007.

Once verified as being clear of fuel, Chapelcross will move to a "new post-defuelling structure," scheduled to begin in September 2013, as work continues to prepare the site for entering into interim care and maintenance in 2017. Final site clearance is expected by 2095.

Oldbury transformer

The Oldbury generator transformer is moved offsite (Image: Magnox)

Meanwhile, Magnox reported that the generator transformer has been removed from the site of the Oldbury nuclear power plant in Gloucestershire.

The transformer - measuring over four metres high, four metres wide and nine metes long - weighs over 170 tonnes. It contains more than 30 tonnes of copper and some 120 tonnes of steel.

It has been transferred to Sharpness Docks on a specialist low-loader truck where it will be sent for recycling. Income from recycling the scrap metal will help pay for the UK nuclear decommissioning program.

Built in the 1960s and among the first generation of UK reactors, both of the Magnox reactors at Oldbury were originally scheduled to shut down at the end of 2008. However, the NDA requested permission from the regulator to operate beyond that date, earning revenue to help pay for decommissioning. Unit 2 was eventually shut down in June 2011, while unit 1 shut down in February 2012.

Researched and written
by World Nuclear News