Tiger robots employed for Sellafield clean-up

04 October 2017

Two Saab Seaeye Tiger robotic vehicles are to work in the radioactive ponds at the Sellafield nuclear site in the north-west of England. Saab Seaeye, an underwater e-robotics company, said on 2 October the vehicles' "proven thruster reliability is vitally important in a highly corrosive environment where maintenance intervention is hazardous to humans".

Sellafield Ltd intends that the Tigers, which have a thruster working life of 10,000 hours, to work continuously for six months at a time between scheduled maintenance periods.

Tiger with under-slung manipulator skid - 250 (Saab Seaeye)
Tiger with under-slung manipulator skid (Image: Saab Seaeye)

"Reliability is key for the health of operators," Phil Toomey, technical manager at Sellafield Ltd, said. "They must wash down the Tigers during maintenance checks as exposure to radiation for operators is carefully limited, so unplanned downtime will quickly exhaust their safe working period in any one year," he added.

The Tigers will pick up and sort nuclear material, including radioactive fuel bars. Each fuel bar is around one metre long, weighs 15 kilograms and is gripped in the middle by each Tiger's under-slung manipulator. It is then monitored and identified, and transferred to a skip, which can be removed from the pond for safer storage in a more modern facility, Saab Seaeye said.

In addition to the under-slung manipulator skid, a four-function forward facing manipulator skid is available, together with an under-slung water-jet cleaning skid. Also on board the Tigers are a colour zoom camera and a down and rear-view camera.

Toomey said Sellafield Ltd liked the fact the Tiger's skid technology "makes it easy to swap skids".

Rob Smith, retrievals manager for Legacy Ponds, said the use of the Tigers is a "shift into a 'production line mentality' for waste retrievals". He added: "These machines will be at the nuclear coalface for longer than our existing fleet can manage. They will be our new workhorses for hazard and risk reduction."

Sellafield Ltd plans to have removed all bulk fuel and sludge from its legacy ponds by 2022.

Researched and written
by World Nuclear News