CCFE’s Joining & Advanced Manufacturing team is working on novel techniques for performing safety checks on components at the ITER next-step fusion reactor.

ITER – the large international fusion machine being built in southern France – will have a network of many kilometres of pipes. When they need to be replaced, the pipes will be cut and welded in situ, using robotics or remote handling technology. There are many challenges that will need to be overcome, not least due to the levels of radiation and space constraints.

In areas of ITER where defects could be present in safety-critical, welded structures it will be crucial to use standardised methods to evaluate them. Visual and leak or pressure tests are available to assist in the validation, but comprehensive 100% inspection is required by the nuclear standards and regulators.

The ability to perform checks as part of the weld acceptance process is a priority across ITER and critical for the safety, reliability and viability of the facility when it begins operations in 2025. Radiography, the most mature and recognised technology, is not feasible without significant, application-specific, development. In addition, verifying the welds between pipe walls that are as thin as those that will be found in ITER (~3mm) is unproven using other applicable technologies and not covered by current standards.

IRTF (ITER Robotics Test Facility) is a collaborative program between the ITER Organization and UKAEA, focusing on ITER remote handling feasibility and risk reduction activities. Establishing a weld acceptance process for ITER is the 11th IRTF project, with the first phase of the work split into four work packages.

Joining & Advanced Manufacturing (JAM) specialists from CCFE are working with colleagues from UKAEA’s RACE robotics centre to investigate possible non-destructive evaluation methods that can check the integrity of the welds in the ITER pipes.

JAM has expertise in assessing the suitability of technologies and components for fusion environments. Heather Lewtas, JAM Programme Manager, said: “There is nothing on the market that fulfils ITER’s weld acceptance requirements. Whilst the JAM programme is relatively new, the experience of the people working here and the fantastic network of experts we have developed throughout academia and industry is unparalleled and I am confident in their ability solve this challenge.”

RACE has hosted the IRTF programme since 2017 and worked on projects that include remotely cutting and welding pipes that will be used in ITER. Chris Lamb, ITER Programme Lead at RACE, added: “We know from our experience with IRFT that it is vital that ITER can clarify the integrity of the pipe welds, in situ. Utilising RACE and JAM provides them with the combined expertise they require and is a great example of the breadth of capabilities that UKAEA can offer these projects.”

In addition to using in-house facilities, UKAEA will look to engage with industry and academia, once the first work package has been completed in Spring 2020.

(Image credit: ITER Organization)

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