The UK Atomic Energy Authority (UKAEA) has awarded Tokamak Energy a contract to design, build, and operate a compact spherical tokamak divertor test platform, designated ST825. This device will inform the development of the prototype STEP fusion power plant. The 15-month, £15 million contract is part of Phase 2 of the STEP program, which aims to produce a concept design for a commercial-scale fusion plant by 2024. The work will focus on qualifying components and developing maintenance procedures for the challenging plasma exhaust, or divertor, system. This award follows a competitive tendering process involving other private fusion developers. Source: Nuclear Engineering International

The ST825 platform will be constructed at Tokamak Energy's headquarters in Milton Park, near the UKAEA's Culham campus. Its primary mission is to test divertor technologies under plasma conditions relevant to STEP, specifically targeting high heat fluxes. The compact, high-field nature of the spherical tokamak design, a core focus for both Tokamak Energy and the UK's national program, presents unique challenges for heat exhaust management. This collaboration allows UKAEA to leverage private sector agility and specialized high-temperature superconducting (HTS) magnet expertise to de-risk a critical path component for the STEP design. The contract represents a significant integration of the UK's public and private fusion ecosystems. Source: Nuclear Engineering International

The ST825 platform will be constructed at Tokamak Energy's headquarters in Milton Park, near the UKAEA's Culham campus.

This award is one of several recent UKAEA contracts aimed at accelerating the UK's fusion supply chain. In a parallel announcement, Canadian company General Fusion was awarded a contract to test its proprietary liquid metal wall technology, while First Light Fusion received funding to work on projectile-based inertial fusion target delivery systems. These contracts, alongside the one for Tokamak Energy, are part of a broader strategy to engage the rapidly growing private fusion industry to solve specific technical hurdles for the national program. By outsourcing these specialized R&D work packages, the STEP program aims to parallelize development streams and tap into diverse technological approaches. Source: Nuclear Engineering International

The contract positions Tokamak Energy as a key hardware supplier and technical partner for the national Spherical Tokamak for Energy Production (STEP) effort. The company's experience with its own ST40 device, which achieved a 100-million-degree Celsius ion temperature, provides a relevant foundation for the ST825 project. The focus on divertor solutions is critical, as managing the intense heat and particle flux at the plasma edge remains one of the most significant engineering challenges for any magnetic confinement fusion device aiming for commercial viability. Successful operation of the ST825 testbed will provide crucial data for the final STEP divertor design and its remote maintenance strategy. Source: Nuclear Engineering International