Radioactive sludge removed from UK’s Pile Fuel Storage Pond

22 December 2016

Radioactive sludge has been transferred out of the world's oldest nuclear fuel pond for the first time, the UK's Nuclear Decommissioning Authority (NDA) and Sellafield Ltd announced yesterday. The project is being delivered ten years ahead of schedule and for half the expected cost, they said in a joint statement.

Sludge - formed from decaying nuclear fuel, natural growing algae and other debris - has accumulated in the water of the Pile Fuel Storage Pond (PFSP) at Sellafield during its 65-year lifespan. It must be removed so the facility can be safely decommissioned. The PFSP is one of the four ageing facilities at Sellafield which the NDA has prioritised for clean-up.

The project is being delivered for half the predicted £200 million ($246 million) cost. A ten-year project to dewater the pond will start in 2019, while sludge is still being removed.

John Clarke, NDA chief executive, said: "This pond was not designed with decommissioning in mind, and therefore we welcome this work by Sellafield Ltd to begin safe removal of sludge, which is a key step in making the site safer. The removal of the sludge contributes to achieving our overall goal of risk reduction by placing radioactive material and substances under more modern storage arrangements until it is ultimately moved to a Geological Disposal Facility." He added that sludge accounts for one-third of the pond's remaining radioactive content, after 70% was removed earlier this year with the completion of fuel exports.

The first 500-litre drum containing the mud-like substance was moved to an encapsulation plant last week. It is then grouted - rendering the waste passively safe - and processed into a storage state, ready for final disposal in a geological disposal facility. The initial sludge removal involves pumping the material into a purpose-built treatment plant next to the pond, before transfer to the drum filling plant. It will take several years to remove all of the sludge in the pond, according to the statement.

Dorothy Gradden, head of legacy ponds for Sellafield Ltd, said that with the start earlier this year of bulk fuel and sludge removal from our other legacy pond, the company is now "firing on all cylinders" in reducing the hazard and risk in these legacy facilities.

The 100-metre long pond was originally used to store nuclear fuel used to make atomic weapons. All the bulk stocks of fuel have now been removed, leaving sludge as the biggest remaining radioactive hazard.

Researched and written
by World Nuclear News