The Nuclear Decommissioning Authority

Hinkley Recycling Initiative is a UK First

06 October 2008

 

Decommissioning and cleaning up the cooling ponds at nuclear power stations often sets a major challenge for staff.

At Hinkley Point A, they not only rose to the challenge posed by the problem of how to deal with contaminated skips but also devised a unique means of recycling the valuable metals.

For the first time in the UK, following publication of the Government’s Long Term Management of Solid Low Level Radioactive Waste Policy, the Environment Agency authorised the transfrontier shipment of up to 235 tonnes of contaminated steel from Hinkley Point A to be transported to the US between September 2007 and August 2010.

The shipments go to the Energy Solutions Bear Creek facility and are smelted for re-use in the nuclear industry.

It was estimated there were 1,725 redundant skips – used to hold fuel rods from the reactor - in the ponds and dry skip store at Hinkley. Around 96% of those kept underwater would be deemed Intermediate Level Waste unless they were decontaminated.

It was decided to set up a decontamination plant at the site and the former laundry building was chosen to house it. To achieve this, a new clean and effluent waste water handling system, HEPA air handling system, roller conveyor system, a sub-change room, electrics and a self-contained, robotically operated, ultra high pressure water jetting system were installed. The re-vamped building was renamed the Aqueous Decontamination Facility.

 

Between July 2005 and January 2007 the project team retrieved 564 skips from behind the shield wall of the dry skip store. Of these almost half have been processed for the metal smelting project; the rest are in temporary storage awaiting decontamination.

The skip retrieval project also involved removing more than 110 tonnes of rubble and debris from the dry skip store. This was loaded into over 500 drums and transferred for disposal as Low Level Waste.

Originally skips from the Reactor 2 pond and the dry skip store were placed in ISO containers, but they could only house 18 skips. However a plan was introduced to reduce the size of the skips and as a result 102 could be packaged in the containers.

The programme for skip removal and processing of all Reactor 2 pond skips was completed ahead of schedule and operations work moved to the Reactor 1 pond.

 

The site took advantage of this and for the first time in operational history the main pond was declassified to clean conditions. Local stakeholders were invited in to see the work.

The site also took advantage of the opportunity to de-sludge the ponds using a standard swimming pool cleaner.

Throughout the project, numerous innovative radiological controls and dose reducing techniques have been developed. Staff have used numerous types of powered hand tools to reduce the size of the skips and spent thousands of man-hours working in very restricted radiological conditions. In this time only two minor injuries occurred and there were no contamination or radiological incidents.