UKAEA robotic snake shows laser-welding capabilities in pipework

A new laser-welding ‘robotic snake’ developed by the UK Atomic Energy Authority has shown it can operate inside of fusion energy powerplant pipework.

The DEMO snake will be deployed and operated remotely inside a hazardous environment without being touched by humans
The DEMO snake will be deployed and operated remotely inside a hazardous environment without being touched by humans - UKAEA

The £2.7m, seven-year project by UKAEA’s RACE (Remote Applications in Challenging Environments) was delivered as part of EUROfusion’s DEMO programme, the successor to ITER.

Deployed and operated remotely, the DEMO snake can be put to work in 80mm diameter pipes that are packed together with little space for access. 

Tristan Tremethick, lead mechanical design engineer, UKAEA, explained that the pipes are cooling pipes for fusion machines which extract the fusion energy to generate electricity.

“They are high pressure, high temperature pipes which are key to the operation of plants such as STEP (Spherical Tokamak for Energy Production) the UK’s first prototype fusion powerplant, or Europe’s DEMO.”

The project involved creating an ultrasonic sensor-system to move the snake up and down the pipe to identify each precise working location. Tremethick explained that the robot senses distance travelled and thickness of the pipes. This information is used in combination to work out where the robot is in the pipe to verify its location.

“The weld will need to be very high quality as integrity is important,” he said. “UKAEA has designed the robot/welding head to be very accurate when positioning against the weld site. This will build quality into the weld.”

He added: “There will also be a separate set of non-destructive testing sensors deployed to verify the integrity of the weld. As we develop it further, the robot will go through a rigorous development process to ensure that reliability and weld quality is as high as possible.”

The proof-of-concept snake – currently at TRL 3 to 4 - has undergone trials at Culham Science Centre and is patented technology.  

Tremethick said the patent relates to the operating head at the front of the snake.

“There wasn’t a solution to this aspect which combined the laser processing with the capabilities needed in this part of the robot, so we created our own solution,” he said. “The patent was sought to demonstrate origin of this work in the UK. Now that we have shown this concept works, UKAEA will be looking to make use of skills from companies working in this field to progress our ideas and develop the complete solution for fusion and adjacent sectors.”

RACE has also developed a laser cutting tool operating on the same principles as the snake and both can potentially be used for other industry applications.   

EUROfusion consortium consists of experts, students and staff from across Europe collaborating to realise fusion energy, co-funded by the European Commission.  ITER is a fusion research mega-project, based in the south of France, to demonstrate the scientific and technological feasibility of fusion energy.