KUKA robot assists with decommissioning of nuclear plant

It is the largest nuclear site in Europe: Sellafield, formerly Windscale, on the northwest coast of England. The plant was opened in 1947 as part of the British nuclear programme, and the world's first commercial nuclear power plant was built there in the early 1950s. In addition, fuel elements from Great Britain, Europe and Japan were reprocessed at Sellafield.

After decades of nuclear activity, the site is now being decommissioned. Its decommissioning is an enormous challenge for which technology is being used and new techniques are being developed.

Decades-old waste transferred safely

The so-called Pile Fuel Cladding Silo is an old, 18-metre-high silo on the Sellafield site that was built in the 1950s and filled with waste over the following decades, including aluminium fuel cladding, or Magnox swarf, from the days of the first commercial nuclear reactors. For decades, the waste sat in the silo, which was not designed to be safely emptied later. Today, the silo has been described by officials as one of the most hazardous buildings in Western Europe.

The interior of the silo is purged with Argon gas, this prevents the waste from igniting. If the waste were to come into contact with oxygen in the atmosphere it would ignite possibly causing radiation issues.

The Cavendish Nuclear joint venture was contracted to supply plant and equipment to remove this old waste from the silo to allow it to be placed into safe storage. For Cavendish Nuclear, KUKA developed and built a robotic system that assists in the transfer of waste into safe containers.

Automation minimises risks

The robotic cell removes bolts from the lid of the empty waste container. The lid is removed in a separate shielded room and the container is filled with waste. The lid is then replaced and returned to the robotic cell. The robot replaces the bolts to a specified torque and wipes the container with a swab. This swab is analysed to ensure there is no contamination present. If clean the container can be safely exported from the plant and laced into storage.

Operators are removed from the process area removing the potential of them being exposed to harmful radiation. "We worked closely with Cavendish Nuclear on the design and delivery of the robot system, and for the past four years the robotic cell has successfully supported the decommissioning of the plant," says KUKA nuclear expert Dave Burns.