Contaminated equipment recovered from nuclear fuel storage pond

Paul Boughton

Sellafield Ltd removes 100 tonnes of contaminated equipment from world’s biggest open-air nuclear store.

Nuclear experts at Sellafield in the UK have successfully removed one hundred tonnes of contaminated redundant equipment from the oldest fuel storage pond at Europe’s oldest and most complex nuclear site.

The 60-year-old pond, known as the Pile Fuel Storage Pond (PFSP), has to be emptied carefully as part of a plan to clean-up and decommission the oldest nuclear facilities in the UK.

The metal waste retrieved from the ageing facility is the equivalent in weight of a blue whale or a Boeing 757 aeroplane.  Although there remains a further 650 tonnes of contaminated metal to be retrieved from the pond,  removal of the first 100 tonnes demonstrates great progress on the programme to successfully decommission the facility.

The pond was initially constructed to store fuel from the Windscale Pile reactors, whose primary focus was producing plutonium for the UK’s nuclear deterrent.

The storage pond stopped receiving fuel in the 1970s, but to this day the PFSP remains the largest open air nuclear storage pond in the world, at 100 metres long.

Dorothy Gradden, head of programme delivery in the Pile Fuel Storage Pond, said: “Our nuclear forefathers developed a technology that helped the UK secure a seat at the global power table in the aftermath of the Second World War. The oldest plants at Sellafield were built in a time before computers existed and with little thought given to how they would be decommissioned. The challenge for this generation of nuclear pioneers is to safely decommission those earliest facilities as cost effectively as we can.

“When you are decommissioning a facility as old as this, issues can and do arise which mean that carefully laid plans and schedules need to be changed – and this happened frequently for us and the operations team has developed additional skills to meet all new challenges."

Derek Carlisle, PFSP head of projects said: “Sometimes it’s difficult to appreciate the decommissioning progress being made, because by the very nature of what we are doing things can take a long time and seem to cost a lot of money.

“However, when you think about 100 tonnes of equipment – the size of a whale or a Boeing 757 – it really does give you some scale as to the difficulty in removing that much mass from the biggest, and one of the oldest, nuclear storage ponds in the world.”

The PFSP was the very first nuclear fuel storage pond constructed at Sellafield. Construction started in 1948 and the pond was commissioned and started to receive fuel in 1952.

Originally nuclear fuel from the Windscale piles – constructed specifically to make plutonium for the UK’s nuclear deterrent – was received, de-canned and cooled in the facility.

Later in the 1950s the pond was adapted to receive fuel from Magnox power stations, the first of which in the world, Calder Hall, was opened at Sellafield in 1956.

Following the closure of the Windscale Pile reactors and the commissioning of the new First Generation Magnox Fuel Storage Pond, operations in PFSP were scaled down.  When decanning in the plant stopped in 1962 the pond continued to be used as storage for fuel, contaminated items, and operational waste.

Derek added: “The 100 tonnes of contaminated metal we have removed so far has been cleaned up for disposal in the national Low Level Waste Repository near Drigg.”

Highlights in the retrievals programme to date include:

* Removal of the very last remaining pile fuel decanner, weighing in at over one tonne;  

* Recovery of two tall tools or masts – similar in height to an average two-storey house - lifted from the pond and size reduced in situ;

* Eight of the 30 waste and transport flasks recovered each weighing 2-3 tonnes;

* Stripping out and export of redundant metal structures above and below the water line in the pond bays.

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