FANUC robots key in nuclear decommissioning
ARC Mate 120iC and M-900iB/360 robots from FANUC have played a starring role in a pioneering waste size reduction project as part of Sellafield’s ongoing decommissioning process. In a first-of-its-kind autonomous application designed and delivered by integrator Cyan Tec, the skip sorting and laser cutting cell has reduced the amount of space needed to store radioactive waste to a third of its original footprint.
The cell has also slashed the time it takes to dismantle and repack radioactive skips from months to minutes, whilst eliminating human involvement in this hazardous operation.
Background: a major pond cleanup operation
Cleaning and decommissioning First Generation Magnox Storage Ponds (FGMSP) has become a major part of Sellafield’s ongoing nuclear cleanup efforts. To facilitate this, the skips that are stored in the ponds need to be removed. However, the limited availability of storage space for the skips once they have been extracted presents a challenge. With a track record in building turnkey automation, laser and robotics solutions for the nuclear industry, Cyan Tec was called upon to devise a solution for a localised size reduction process that would minimise the storage footprint of the removed skips.
“Our idea was to cut up the skips so they would occupy less space – in this way, three skips could effectively be reduced to one,” explained Tony Jones, Managing Director of Cyan Tec.
Previously, this type of work had always been performed manually, on the mistaken assumption that it was not possible to automate such a task. Operators wearing hazmat suits would use angle grinders to cut storage containers into pieces, but to limit exposure to radiation, they could only work for very short intervals. This meant that it would have taken approximately one month to break down each skip.
Fraught with challenges
Automating this operation was no easy task, for a number of reasons. Firstly, the cell needed to fit into a very small area and, once operational, be completely autonomous, requiring no human intervention. Secondly, whilst the skips were all welded fabrications, their dimensions and their construction varied, and Cyan Tec had no visibility on the range of these dimensional differences. And thirdly, because of the considerations around safety and radioactivity, there were limited opportunities for commissioning and testing the system prior to installation.
Cyan Tec designed and installed a full turnkey laser cutting and handling system to operate autonomously within a nuclear bunker. The entire cell is operated remotely, from a control room 100 metres away.
The system was built at Cyan Tec’s Leicester facility and then installed at Sellafield and tested on non-radioactive skips before being put into action on contaminated skips under the supervision of project partner TKE Nuclear.
At the heart of the system are two six-axis FANUC robots: a compact ARC Mate 120iC for cutting, and a heavy duty M-900iB/360 equipped with two interchangeable end-effectors: a scanning head and an electromagnet for handling the panels. When in scanning mode, the M-900iB builds a 3D image of the skip within the machine’s control system. MeshLab software compares the scanned skip with a reference skip, enabling the control system to adjust the parameters of the ARC Mate 120iC robot (equipped with a laser cutting head) and determine the optimum cutting pattern.
The robots were selected above all else for their world-renowned reliability, which has been proven in accelerated life tests and is underpinned by an eight-year zero maintenance promise.
“The cell had to be 100% reliable, as there was no opportunity for going in and fixing it if anything went wrong. That was why we chose technology that had already been proven in demanding industries. FANUC’s robots have a strong track record of working in demanding automotive plants with very high uptime figures, and demonstrate the highest reliability of any robot manufacturer,” said Tony.
FANUC’s robots also aligned with Cyan Tec’s strategy of using commercially available technology wherever possible, as this was a test case for a COTS (Commercial Off The Shelf) project in an industry where an expensive bespoke approach has traditionally been the norm.
Results: from one month to one hour
The robotic cell was originally designed to size-reduce 50 skips of nuclear waste. It was so successful that it has since been used to process further skips of waste in a fraction of the time and with none of the health and safety implications of a manual operation.
“This system has revolutionised the handling and size reduction of skips and demonstrated that a COTS approach can work in the nuclear industry,” said Tony.
“It is incredible to think that by automating this task, we have been able to reduce the time it takes to cut down and repack a skip of waste from approximately one month to just 60 minutes. FANUC’s technology has been pivotal in achieving this outcome and our confidence in the solution we have delivered is rooted in our confidence in FANUC’s reliability and support.”
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