The removal of highly radioactive sludge from an ageing fuel storage pond at the Sellafield site in Cumbria started on 23 of March, says the UK’s Office for Nuclear Regulation (ONR).

The regulator said that the removal of waste from the First Generation Magnox Storage Pond is a further major development in ONR’s new long-term strategy to help drive improvements.

The reduction of hazard and risk, quickly and safely, at Sellafield is a key national priority and ONR’s number one regulatory priority, it said.

The FGMSP, which dates back to the 1950s, was built to store, cool and prepare used Magnox nuclear fuel for recycling into new fuel. Over the years it has been used to accumulate quantities of spent nuclear fuel, waste materials and fuel fragments. Sludges from corrosion of fuel cladding have also accumulated, and an estimated 1500 cubic metres of radioactive sludge is lying at the bottom of the pool.

Sellafield has now begun to remove and store the sludges from the pond in a newly built Sludge Packaging Plant 1. The plant was completed in June 2014, after a six year construction period. The main contrators were Doosan Babcock and Balfour Beatty.

"We’re making history at Sellafield by transferring the first sludge using a tried and tested pump to a new £240 million state-of-the-art sludge storage plant containing three enormous stainless steel buffer storage vessels, each of which is the same volume as seven double decker buses," said head of the FGMSP Martin Leafe.

ONR’s Director of the Sellafield Programme, Andy Lindley, said: "The first transfer of sludges is a further significant milestone in our long term aim to drive forward reduction of hazard and risk at Sellafield."

"This is a complex operation and a first of its kind at Sellafield. There will be challenges in removing this material and we acknowledge that there may be some setbacks. This is highly hazardous waste and its removal will take some years to complete. But the longer-term benefit is huge in terms of overall hazard and risk reduction."

Photo: First sludge removal (credit: Sellafield Ltd)