The first batch of waste has been removed from the Magnox Swarf Storage Silo (MSSS) at the Sellafield site in the UK. The facility was built in the 1960s to store waste from the UK's earliest nuclear reactors in water-filled chambers.

Workers begin removing fuel from the MSSS (Image: Sellafield Ltd)

The MSSS's 6-metre-deep silos were constructed to accommodate the magnesium swarf waste produced by the decanning of Magnox fuel prior to reprocessing. The swarf was stored underwater, and the first facility of six silos began operations in 1964. By 1983 a total of 22 silos had been built, but by the early 1990s wet storage of Magnox swarf was superseded by dry storage.

The MSSS closed in 2000 and has been prioritised for clean-up by the UK's Nuclear Decommissioning Authority (NDA). "Due to the age of the building, the contents held inside, and the fact that it was never built with decommissioning in mind, it is one of the most hazardous nuclear facilities on the Sellafield site and in the Nuclear Decommissioning Authority's estate," the NDA said.

Teams at Sellafield have now started removing the waste held inside the MSSS, putting it into purpose-built stainless steel waste containers and moving it to modern storage on the Sellafield site. Eventually these metal waste boxes will be held safely inside a new highly-engineered store currently being built on site. All of the waste will eventually be sent to a geological disposal facility when that becomes available.

"This is the culmination of decades of preparation by hundreds of people across our Sellafield Ltd and supply chain," said Head of Programme for MSSS, Chris Halliwell. "As well as maintaining the original concrete structure of the building, we have designed and are installing purpose-built retrieval machines.

"The first of our three retrievals machines has now started the job which will take another 20 or so years to complete. Our teams use this machine to reach down into the compartment of the silo, grab waste from inside, and put it inside containers that have been designed and manufactured for the job."

He added, "Once empty of waste, our attention will turn to decommissioning and ultimately knocking down the silo building."

Researched and written by World Nuclear News