A consortium of nuclear fusion experts led by Atkins – a member of the SNC-Lavalin group – and Assystem, a specialist in energy transition, has been appointed by the UK Atomic Energy Authority (UKAEA) as a service delivery partner for engineering for its Spherical Tokamak for Energy Production (STEP) programme, which aims to demonstrate the commercial viability of generating energy using nuclear fusion.

Over the next two years the STEP EDP consortium will play a key role in the STEP programme, which aims to design and build a prototype of a commercial-scale fusion power plant by 2040.

The completion of the design of the concept is one of the two key Tranche 1 targets to be achieved by 2024, which will enable the UKAEA to progress to the next phases and achieve its objectives. The UK Government is providing GBP220 million ($267m) of funding for the first phase of STEP.

The consortium is led by Atkins as prime contractor, alongside international engineering and digital services company Assystem. Atkins and Assystem have a long history of successful collaboration on nuclear power and fusion projects, including as architect-engineer through the Engage consortium for the International Thermonuclear Experimental Reactor (ITER) under construction in southern France.

The consortium combines its expertise with the skills of these supply chain partners: Oxford Sigma, specialist in materials technology and safety of fusion components in vessels, Kyoto Fusioneering, specialist in components in tanks and tritium, and Ansaldo Nuclear. Together, the consortium will bring together more than 30 years of fusion experience including the Joint European Torus (JET), STEP, ITER and DEMO (the planned successor to ITER).

Christophe Junillon, Managing Director of Nuclear & Power EMEA for Atkins, said: " Commercialising fusion power is key to unlocking an abundant source of safe and clean energy, and the ambitious STEP programme positions the UK as a world leader in such complex projects. Simon Barber, Managing Director of Assystem in the UK, said: "Assystem's role in this consortium of delivery partners for STEP is underpinned by a long-term commitment to developing the UK's fusion capability, leveraging a mix of UK skills, decades of experience on international fusion projects such as ITER and working with fusion specialist UK SMEs.” Tristram Denton, Head of Business Development and Programmes for STEP, said: “It is clear that we need to make significant changes to address the effects of climate change, and STEP delivery partners will play a crucial role in our quest to make the merger a reality. ”

Consortium members have an established relationship with the UKAEA: Atkins was appointed as STEP's Power Infrastructure Partner in May 2022, in addition to its roles as Trade Lanes Partner, sites, partner for cost modelling, and development of STEP's integrated plant solution to define a conceptual mechanical handling and maintenance strategy. Assystem is currently carrying out the design project for the shielding of STEP and has extensive in-vessel experience, notably as a pioneer of the lithium breeder concept, as well as expertise in robotics and remote manipulation within the framework of the LongOps programme.

The Consortium members have previously worked together to deliver wide-ranging projects released through UKAEA's Engineering Design Services (EDS) and Embedded Engineering Resources (EER) frameworks, with both Atkins and Assystem holding Tier 1 positions.

Image: Cutaway of the planned STEP building (courtesy of UKAEA)