Two Saab Seaeye Tiger robotic vehicles are to work in the radioactive ponds at the Sellafield nuclear site.
They were chosen because their proven thruster reliability is vitally important in a highly corrosive environment where maintenance intervention is hazardous to humans.
“Reliability is key for the health of operators,” explains Phil Toomey, Technical Manager at Sellafield Ltd. “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.”
Sellafield Ltd intends the Tigers to work continuously for six months at a time between scheduled maintenance periods.
The Tiger’s thruster working life of 10,000 hours was a major appeal. Phil Toomey describes how the Tiger’s role is to help clean up and empty the legacy storage ponds by picking up and sorting nuclear material, including radioactive fuel bars. The nuclear waste can often be buried in about 30 cms of sludge, which is also highly radioactive and hazardous.
Each fuel bar is around one metre long, weighs 15 kilos and is gripped in the middle by the Tiger’s under-slung manipulator, monitored and identified, then transferred to a skip which can be removed from the pond for safer storage in a more modern facility.