A consortium led by Atkins as prime contractor, alongside Assystem, has been appointed by the UK Atomic Energy Authority (UKAEA) as Engineering Delivery Partner (EDP) to its Spherical Tokamak for Energy Production (STEP) programme.

A cutaway of the planned STEP building (Image: UKAEA)

The aim for the first phase of work on STEP is to produce a 'concept design' by 2024. The UK government is providing GBP220 million of funding for the first phase of STEP. The next phase of work will include detailed engineering design, while all relevant permissions and consents to build the prototype are sought. The final phase is construction, with operations targeted to begin around 2040. The aim is to have a fully evolved design and approval to build by 2032, enabling construction to begin.

Atkins - a member of the SNC-Lavalin Group - and Assystem have a long history of collaboration across nuclear and fusion energy projects, including their work as architect-engineer for the International Thermonuclear Experimental Reactor (ITER), through the Engage consortium.

The STEP EDP consortium includes: fusion in-vessel component materials technology and safety specialist Oxford Sigma; in-vessel components and tritium specialists Kyoto Fusioneering; and Ansaldo Nuclear. Combined, the consortium will bring more than 30 years' experience in fusion delivery from across JET (Joint European Torus), ITER, STEP and the Demonstration Fusion Power Reactor (DEMO).

The consortium members have an established relationship with UKAEA: Atkins was appointed Power Infrastructure Partner to STEP in May 2022, in addition to its roles as Commercial Pathways Partner, Site Selection and Development Partner, Cost Modelling Partner, and developing STEP's Integrated Plant Solution to define a conceptual mechanical handling and maintenance strategy. Assystem is currently delivering the STEP shielding design project, and has a wide range of in-vessel experience including pioneering the safe lithium breeder concept, and robotics and remote handling expertise under the LongOps programme. The consortium members have previously worked together to deliver wide-ranging projects released through UKAEA's Engineering Design Services and Embedded Engineering Resources frameworks, with both Atkins and Assystem holding Tier 1 positions.

"The commercialisation of fusion energy holds the key to unlocking an abundant source of safe, clean energy that will power a net-zero future, and the ambitious STEP programme positions the UK as a global leader in such highly complex projects," said Christophe Junillon, Managing Director of Nuclear & Power EMEA for Atkins. "A viable, investible concept design is central to UKAEA’s ambitions and Atkins is proud to extend our involvement in STEP’s development through this consortium."

Assystem UK Managing Director Simon Barber added: "The STEP project is a fantastic opportunity for the UK to continue its leading role in the global race to deliver a commercially viable fusion power plant. Assystem's role in this delivery partner consortium for STEP builds on a long-term commitment to the development of UK fusion capability, harnessing a blend of UK skills, decades of experience on international fusion projects such as ITER and collaborating with UK fusion specialist SMEs."

"Fusion has great potential to deliver safe, sustainable, low-carbon energy for generations to come, and STEP is leading the way," said Tristram Denton, Head of Commercial and Programme Development for STEP. "It's an ambitious programme operating at the forefront of science, technology and engineering. It's clear we must make significant changes to address the effects of climate change, and STEP's delivery partners will play a crucial role in our quest to making fusion a reality."

In December 2020, the government called on local communities across the country to put forward proposals to host the STEP plant. Communities had until the end of March to submit their nominations and were required to demonstrate that their local area has the right mix of social, commercial and technical conditions to host the new plant - such as adequate land conditions, grid connection and water supply. A total of 15 potential sites were subsequently long-listed.

The UKAEA - which carries out fusion energy research on behalf of the government - announced in October 2021 that, following an initial phase of assessment, five bids to host STEP had now been shortlisted. These are: Ardeer in North Ayrshire; Goole in East Riding of Yorkshire; Moorside in Cumbria; Ratcliffe-on-Soar in Nottinghamshire; and the so-called 'Severn Edge' bid from South Gloucestershire and Gloucestershire.

The site of the demonstration plant is expected to be announced at the end of this year.

Researched and written by World Nuclear News