Mobile robots help clean up legacy

In September, four-legged "spot" robots, developed by US-based Boston Dynamics, were used to negotiate pitch-black conditions to map an evaporator cell in the fuel cycle area of the Dounreay site in Scotland. Dounreay was the UK’s former fast reactor test facility, which operated from 1955 to 1994. It is now being decommissioned and ongoing clean-up and dismantling work is continuing.

Spot’s task was to map out the four-storey cell, collecting important radiological data for the team to use when planning the decommissioning of the facility; and to gain useful experience on how the robot and survey equipment should be used.

A team of 12 supported the robot trials. This includes Dounreay staff led by Project Manager Bernie Jones, as well as staff from Createc, the systems integrator for Spot, who are working with Dounreay on a series of seven use cases for the robot to be carried out over the next few months.

The site joiners constructed a wooden mock-up of the evaporator cell entrance and temporary containment in a clean area to test the abilities of the robot and train its operators before the work moved into the actual evaporator cell itself.

Once inside the evaporator cell a Spot robot, covered in a protective suit, collected data to give the team a complete 3-dimensional map of the area. It also collected the data needed to create a full dosimetry map showing areas of higher radioactivity, which will enable the team to develop a radiological fingerprint.

“By doing the initial groundwork, Spot has shown us the hazards that might affect workers who are tasked with the decommissioning, said Bernie Jones. “We will use the data to ensure that we mitigate those hazards and keep our people safe. This work also has the potential to save money on our decommissioning investigation.”

Createc’s Energy MD, Will Newsom, said: “Over the course of five days, we deployed two Spots in multiple entries to the cell. The environment we were exploring was complex as it had not been accessed in over 20 years, so the team didn’t know what to expect: that’s what made the deployment so challenging.” He added: “Using our innovative NV-Explore sensor, the team captured 3D radiation maps. At the same time, one Spot with a robotic arm was used to take several physical samples for lab analysis.”

Professor Melanie Brownridge, Technology & Innovation Director for the UK Nuclear Decommissioning Authority (NDA) noted that the work had shown the potential applicability of the technology across the NDA group. “Shared learning and collaboration across our group is essential to the successful delivery of our mission. We have many common challenges and the potential to learn and share the impact, benefitting from innovative approaches such as this is truly significant.”

Dounreay now plans to validate the suitability of several different types of sensors, combined with Spot, to support the digitalisation of existing on-site processes. It is hoped this will demonstrate the multi-tasking value of the quadruped for nuclear sites, and its ability to carry out practical work for multiple teams.

In 2022, Dounreay also used another robot – named Lyra – to inspect a ventilation duct in redundant nuclear laboratories and map radioactive materials. Lyra traversed 140 metres of duct from a single entry point and provided operators with detailed radiological characterisation information to help plan safe and efficient decommissioning of the laboratories. Human access to this area is currently impossible due to both the size of the duct and radiological risks.

Lyra was developed by researchers at The University of Manchester, working within the Robotics and Artificial Intelligence for Nuclear (RAIN) Hub and with considerable guidance from technical and operations staff at Dounreay Site Remediation Ltd (DSRL). Lyra was designed from the start as a low-cost robot, featuring five radiation detectors, a laser scanner for positioning, two cameras, lights and a manipulator arm that was used to take swab samples of the radioactive contamination from the walls or floor of the duct.

Lyra was fitted with tracks and given a relatively high ground clearance to enable it to clear the considerable amounts of rubble that lay in the duct. The radiation sensing package was designed to be able to measure beta, gamma, x-ray, and neutron radiation.

Cameras were attached to the end of the manipulator arm which allowed for detailed inspection of any areas of interest that were identified during the survey. Lyra is controlled via a joypad, which is used for driving, and a compliant manipulator arm whose motion is copied by the arm on the robot.

The radiation sensing package coupled with the LIDAR and live camera footage enabled a 3D, time stamped video to be developed with the radiation readings as measured overlayed onto the video such that any point of interest or high radiation measurement could be pin pointed within the duct.

Barry Lennox, RAIN Director said: “We wanted to demonstrate that the robot could be used successfully in active areas. We added fail safe devices, including a remote “reboot” switch, and a winch to enable us to physically retrieve the robot if it got stuck on the debris in the duct. The survey has demonstrated Lyra’s reliability in active areas.”

Lyra was untethered, but the winch retrieval mechanism, could be used to drag it back to an access point or to shift it off rubble if it became beached. An independent, wireless reset device rwas also incorporated that enabled Lyra to perform a ‘hard reset’ if necessary.

The deployment of Lyra was completed in partnership with the operations team at DSRL. It was supported by innovation and technology transfer specialists FIS360. Their Managing Director, Frank Allison said: “The development and deployment of Lyra highlights the benefits that robotics technology offers the nuclear industry and the importance of academia, end-users and businesses in the supply chain working together. It is only through collaborative working, like this, that solutions can be developed for complex challenges, such as surveying the Dounreay duct.”

Although the Spot robots for the latest trials were delivered to Dounreay in June, previously Spot had been deployed at other NDA sites most notably at Sellafield. There they had become a mascot for the range of robotic tools and innovations that are transforming work there. Sellafield is one of the world’s most complex legacy clean up sites with numerous facilities including reactors that were part of the UK’s post-war atomic weapons programme.

Sellafield’s remediation teams are leading Spot’s deployment for Sellafield Ltd, working with Createc, the UK Atomic Energy Authority (UKAEA) and manufacturer Boston Dynamics. Spot made its debut on the Sellafield site in October 2021 when it undertook three days of successful trials at Calder Hall, the former nuclear power station which is now being decommissioned. Calder Hall’s former turbine hall provided the perfect tricky terrain to test Spot’s agility.

Valuable information was collected through laser scanning and gamma radiation imaging using a system provided by Createc.

The robot worked wearing a suit specially designed and manufactured by the UKAEA which protected it from radioactive contamination. This was provided via the National Nuclear User Facility for Hot Robotics (NNUF-HR). Chris Hope, remediation capability development manager, Sellafield Ltd said it was a really challenging task. ”We deployed Spot into a complex, cluttered, highly contaminated area with a mission to capture information. The quality of the data we captured is fantastic and will help us with our decommissioning and waste planning.” This type of survey previously depended on operators manually deploying equipment in hazardous environments wearing full protective equipment. Spot’s protective
suit also proved effective. The robot was monitored and cleared by the health physics team, and was thus able to subsequently leave the Sellafield site. This is an important consideration for more widespread robotic deployments.

Charlotte Brew, sub project manager, Sellafield Ltd, said: “We started with demonstrations of its potential and six months later, we’re using it to accelerate high hazard reduction. This work wasn’t meant to start happening until the late 2020s but identifying Spot like this has brought it forward. Just one robot dog is making a massive difference.

Sellafield Ltd operator, Paul Lupton said: “Before we would have two operators go in, and this would need up to seven other people, taking up to four hours to prepare for an hour’s work. With Spot we do an hour, the battery runs out and we re-charge. Even just an entry to take a photograph would be a major job. Now we just use the dog. It’s all there inside the cell waiting for you.”

Melanie Brownridge, NDA Technology & Innovation Director said: “This is a great example of taking innovation all the way through to deployment and being able to actually see the benefits being realised on our sites. This exciting technology is helping move our people away from harm, reducing our costs significantly and could help us deliver our mission years earlier than planned.” She added: “We are also seeing the benefits across the NDA group as we share our experiences to overcome common challenges across multiple sites. Well done to the team for not only embracing innovation but making it business as usual.”