Robots at Sellafield have started to remove radioactive sludge from the most hazardous place at the site.

The sub-section of the First Generation Magnox Storage Pond, known as D-bay, was used to deposit radioactive sludge, which started to accumulate in the plant in the 1970s.

The sludge is now being removed using robotic arms, following 10 years of planning with supply chain partners ACKtiv joint venture and Jacobs.

Dorothy Gradden, head of legacy ponds for Sellafield Ltd, said: “D-bay has always been one of our biggest headaches at Sellafield.

“It is a concentration of a problem in our most complicated and hazardous legacy facility.

“After years of designing, making and installing the necessary equipment, we are now delighted to be safely reducing the hazard day-by-day.

“The dedication and innovative thinking of more than 800 people at Sellafield and in our supply chain that has ensured that we safely arrived at this ‘man on the moon’ moment for this plant. I’d like to thank and congratulate them all.”

D-bay holds the equivalent of 35 concrete mixer trucks full of radioactive sludge, which is a by-product formed from decaying nuclear fuel and other debris.

It has been a no-go area for around 40 years, because the sludge is close to the surface of the water and due to the volume of radioactive material.

The work has been done remotely using Brokk manipulator robots, operated by people who control them from behind a shielded wall.

The robotic arms are attached to an overhead travelling crane and various tools can be attached to the arm for different tasks.

A suction device is used to up the sludge, while other tools allow the arm to pick up larger waste items and chop them into smaller pieces, so that the sludge can be accessed more easily.

The material is being transferred to a plant for safe storage.

Now 66 years old, the pond was originally used to store, cool and prepare Magnox fuel for reprocessing.

Work is ongoing to remove waste from the main pond, which is due to be emptied by 2031.