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Visit marks Rawwater's development of unique metal seals for TEPCO and Sellafield decommissioning activities

7 April 2022 – UK-based seal and defect repair specialist Rawwater Applied Technology Ltd, today welcomed delegates from National Nuclear Laboratory Ltd (NNL) and Tokyo Electric Power Company (TEPCO) to its Warrington facility.

The visit was held to mark the next stage of a collaborative project, which also involves Sellafield Ltd and aims to adopt Rawwater’s in-service alloy seals to support various challenges during nuclear decommissioning activities.

TEPCO visitRawwater is developing M3 Molten Metal Manipulation: a range of low-melting-point, reversible alloy seals and application techniques for the rapid recovery of leaks and cracks in civil structures, seals, joints, flanges and pipelines, as well as planned preventive maintenance.

Working in association with NNL on different aspects of the technology, TEPCO and Sellafield Ltd first began exploring the use of Rawwater’s M3 Molten Metal Manipulation for decommissioning in 2019 and achieved extremely encouraging results. Since then, Rawwater has further developed M3 to include M3Spray – a kinetic molten alloy spray, and M3CollarCast – a process that uses specially designed casting collars for the application of rapidly curing molten alloy seals around pipes, joints and flanges.

“It was a pleasure to welcome guests from NNL and TEPCO to our facility,” comments Kat Lennox, managing director of Rawwater Applied Technology Ltd. “It was especially rewarding to meet Mr Kohei Sohda, our key TEPCO project contact.”

Rawwater’s work for Sellafield Ltd is focused around its M3Spray, which is available with a range of hose lengths for manual or remote application. Rawwater’s work with TEPCO surrounds M3CollarCast and the creation of application-specific alloy seals. As both technologies are fully reversible, they do not foreclose future decommissioning options. They can also be applied against flowing leaks, without the need to drain systems or shut down processes. Reapplication is straightforward and recovered alloys can be reused.

Rawwater made the transition into the nuclear sector through Sellafield's Game Changers programme. Game Changers is an innovation programme designed to identify and develop technologies that can offer significant, pioneering advances in the decommissioning of Sellafield. The programme is delivered by NNL and FIS360, specialists in supporting innovative technologies from concept to commercial production.

As an indication of the considerable opportunities offered by M3 Molten Metal Manipulation, the UK’s National Grid is also exploring the use of the technology to seal harmful SF6 greenhouse gas leaks from small-bore pipework.