Sellafield robot technology for nuclear decommissioning

Sellafield Ltd has carried out a technically challenging piece of work in a high radiation environment in order to pave the way for decommissioning one of the high hazard plants at Sellafield.

Bespoke robotic technology has been developed in order to safely remove a significant hazard associated with the 60-year-old First Generation Magnox Storage Pond (FGMSP), so meeting the Nuclear Decommissioning Authority’s (NDA) focus of delivering progress in tackling the nuclear legacy.

The scope of the work involved using a unique Powered Remote Manipulator Arm (PRM) to firstly isolate and remove redundant pipework in a high radiation area, and secondly to clean and seal a contaminated pond wall. The redundant pipework posed a significant risk and has been isolated with special sealants, before its remote removal. The robotic arm then scabbled the pond wall and applied a specialist coating to seal the concrete.

Paul Farran, Head of Projects, FGMSP said: “The operation demanded surgical precision in an industrial context and the completion of this vital piece of work helps us get on with the job of retrieving nuclear wastes from the pond.

“We’ve worked with specialist contractors SA Robotics to develop a robot that could work in a high radiation area, where obviously we couldn’t send our workforce. We’ve also drawn on space age technology by using software originally developed by NASA, to control our robot. In addition new resins and foams had to be developed in conjunction with AMEC to both key and seal the pond wall, and to coat and isolate the pipework under extreme conditions.”

The successful completion of this work will now allow Sellafield Ltd to move forward with emptying of the pond and the eventual decommissioning of the building.

The FGMSP was not built with decommissioning in mind, unlike modern nuclear facilities. Also, the standards of construction were different in the 1950s and would not meet today’s exacting requirements. Moreover, due to the age of the plant and that it has been open to the elements, the building has deteriorated. These factors meant that significant improvements have had to be made to bring the building to a state that it can be safely decommissioned.

Jim French, Nuclear Management Partners’ (NMP) Executive Decommissioning Director said: “We are committed to accelerated decommissioning and addressing the intolerable conditions that exist in some of our aging legacy facilities as soon as possible. NMP has brought their expertise to Sellafield specifically to drive through decommissioning projects that really will make a difference. Completion of this remediation work is a significant achievement towards decommissioning the First Generation Magnox Storage Pond (FGMSP) safely.”

Mark Steele, (NDA) Head of Programme for Sellafield said: “Sellafield faces a complex set of decommissioning challenges in dealing with the legacy facilities on the site. Often innovative approaches and techniques are needed to overcome them and applying the expertise that exists on the site is key to successful delivery. Continuing this approach will help in our drive to accelerate progress on risk and high hazard reduction.”

Significant preparation work had to be carried out before work could start on the job. This included the construction of a full scale mock up of the facility in Whitehaven, to prove the equipment, method and safety of the procedure, along with providing a low risk environment in which to train the operatives.

Paul Farran, Head of Projects, FGMSP added: “The full operation was practised again and again in the test facility for 80,000 operating hours. Through the intense practice, we were able to satisfy ourselves and our regulators that the job could be flawlessly executed and that every eventuality has been considered and prepared for. At all times safety was the over-riding priority and although the job was high risk, it was a job that was long overdue.”