Terrestrial Energy has signed an expanded manufacturing and supply contract with Springfields Fuels, a Westinghouse subsidiary. The agreement is for an Integral Molten Salt Reactor fuel pilot plant in the United Kingdom.
This agreement covers design, deconversion, fabrication, packaging, and transportation services, with construction scheduled to begin in 2026 at the Springfields site near Preston.
The pilot is intended to underpin future commercial fuel production for a prospective fleet of IMSR plants in the 2030s. The company framed the move as a supply chain milestone that aligns with its deployment pathway. The contract builds on earlier work at the same site.
Scope and fuel strategy
The new scope brings more of the IMSR fuel value chain under a single programme at Springfields, using existing industrial assets to shorten timelines and reduce capital intensity. Terrestrial Energy’s IMSR design is fuelled with standard assay low enriched uranium below 5 percent, which enables reliance on established transport and regulatory frameworks rather than scarce HALEU supply.
The pilot facility is intended to scale into commercial production once processes are proven and qualified. The expanded contract, which follows a 2023 engagement at Springfields, is presented as a practical route to early market entry using current fuel logistics.
“This expanded partnership with Westinghouse at Springfields represents a strategic milestone in Terrestrial Energy’s Western supply chain strategy,” said Simon Irish.
Terrestrial Energy’s announcement outlines the pilot scope and the 2026 start for construction at Springfields in Lancashire, and describes the SALEU strategy as central to commercialisation.
UK site readiness and oversight
Springfields is the United Kingdom’s licensed nuclear fuel manufacturing site, operated by Westinghouse’s Springfields Fuels Limited on a long lease from the Nuclear Decommissioning Authority.
The Office for Nuclear Regulation lists Springfields as a fuel manufacturing site with routine safety attention and enhanced security attention, reflecting its operating profile and regulatory status. Locating the IMSR pilot there leverages an experienced workforce, existing conversion and fabrication infrastructure, and access to transport links that have served export markets for decades. The site’s regulatory environment includes ongoing public dose monitoring reported through government programmes.
“We are delighted to continue our partnership with Terrestrial Energy to develop a next-generation nuclear fuel at Springfields,” said Tarik Choho, Westinghouse President of Nuclear Fuel. Additional detail on Springfields’ license, ownership and operating remit is available from the Office for Nuclear Regulation.
Commercial timeline
The expanded contract builds on a planning and initial design agreement announced in August 2023, which established the Springfields pilot as the centrepiece of Terrestrial Energy’s fuel strategy. The company’s latest update also references selection to US Department of Energy programmes supporting advanced reactor pilots and fuel supply, aligning technology development with fuel readiness.
The project’s sequencing, pilot first then scale, is consistent with staged qualification in nuclear manufacturing and should inform procurement planning for utilities and process heat users. Corporate momentum also matters, as Terrestrial Energy recently completed a business combination and listed on Nasdaq, which the company says will accelerate commercial deployment plans.
Details of the expanded Springfields contract and the earlier groundwork are set out in the company’s November 5, 2025 announcement and its August 3, 2023 release, while the listing details are in the October 28, 2025 notice.