UK Fusion Week: a UK-US statement, a supercomputer link and up to £3m

The Global Fusion Policy Summit at Mansion House in London on September 14, 2026 is the first entry on the Fusion Industry Association's event listing for UK Fusion Week, which it dates from September 14 to 17, and the week's first two days produced five documents worth reading: a UK-US joint statement issued with seven other governments in the room, a declaration of intent to explore linking the two countries' fusion supercomputers, an expanded Tennessee partnership, a Japanese company's investment in the UK, and a regulatory map for England and Wales.

A UK-US statement on regulatory harmonisation

The Department for Energy Security and Net Zero and the US Department of Energy issued a joint statement closing the summit, co-chaired by UK energy minister Michael Shanks and US Under Secretary for Science Dario Gil, with ministerial and high-level representatives from Canada, France, Germany, Italy, Japan, the Republic of Korea and Finland. The co-chairs commit to developing proportionate, risk-informed regulatory approaches for fusion power plants, to participating in international standards bodies so that fusion standards development proceeds at a pace aligned with technology readiness, and to encouraging collaboration through multilateral fora on harmonised regimes, codes and standards. Separately, they say they recognise the value of working with international partners including the International Atomic Energy Agency. The most concrete line is a position on where standards should start: the statement says fusion safety standards and guidance should be distinct from fission safety standards, and that radiological safety standards are a more appropriate starting point. No funding, timetable or new body is announced.

UKAEA and PPPL sign a declaration of intent to explore linking SUNRISE and STELLAR-AI

The UK Atomic Energy Authority (UKAEA) and the US Department of Energy's Princeton Plasma Physics Laboratory (PPPL) signed a Joint Declaration of Intent at the summit to explore linking UKAEA's SUNRISE supercomputer with PPPL's STELLAR-AI platform, under the name SUNRISE-STELLAR-AI Federation. Per the UKAEA release, SUNRISE is the UK's first AI supercomputer dedicated to fusion, backed by £45 million ($60.7 million at September 15 rates) of UK government money and the first phase of computing infrastructure underpinning the UK's first AI Growth Zone, established at UKAEA's Culham Campus, while STELLAR-AI is PPPL's AI and high-performance computing platform, operated with support from Princeton University. The release says the federation will mean both computers are used to train the same AI models, drawing on experiments at the two laboratories' compact spherical tokamaks, MAST Upgrade in Oxfordshire and NSTX-U in New Jersey, which it says are similar enough in design to suit joint training. The declaration builds on a memorandum of understanding the two laboratories signed in June 2026 and announced on June 25, which UKAEA said covers cooperation including reciprocal staff exchanges, access to major research facilities, joint projects, ITER diagnostics and advanced computing programs. Next steps the two sides have discussed, the release says, include digital twins of both machines and moving computing jobs between platforms that use different hardware; none of that is committed.

Tennessee, TVA and the UK expand their fusion partnership

The State of Tennessee, the Tennessee Valley Authority (TVA) and the UK government announced on September 14 a strengthened partnership on commercial fusion deployment, in a release datelined Nashville and London that Type One Energy republished from TVA. Under the partnership, the release says, the partners will explore cooperation in areas including fusion supply chains and advanced manufacturing; the fusion fuel cycle, including tritium handling, lithium enrichment and breeding blanket materials; scientific and technical exchange between Oak Ridge National Laboratory, UKAEA, universities, national laboratories and research institutions; engagement among utilities, developers, investors and industrial partners on siting, interconnection and offtake planning; workforce development, apprenticeships and talent exchange; coordination on fusion regulation, licensing and safety frameworks; and joint conferences, forums and activities that support global fusion sector growth. The release ties the work to Project Infinity in Tennessee and the UK Infinity Fusion Consortium, naming Type One Energy, TVA, Tokamak Energy, ORNL and UKAEA, and says Tennessee's fusion-specific licensing framework, enacted in June 2026, mirrors the UK's proportionate approach under the Energy Act 2023. Tennessee issued Type One Energy the first license under that framework on August 31, as The Duck Curve reported. The release carries no dollar figure and no signed agreement text. A DESNZ release previewing the summit, published September 14, says the UK "has signed a Letter of Intent with the State of Tennessee agreeing potential areas of collaboration including R&D, skills and workforce development, regulation, and access to supply chains"; the TVA release names no instrument.

Kyoto Fusioneering puts up to £3m into a breeder blanket experiment for STEP

Tokyo-based Kyoto Fusioneering announced on September 15, in a release datelined Culham, a strategic investment of up to £3 million (about $4.0 million at September 15 rates) in the UK fusion sector, to design and manufacture a lithium oxide solid breeder blanket experiment and begin irradiation testing with online tritium measurement. The company says the experiment is designed to deliver progress for the UK's STEP programme and that the funding will grow its Culham-based team; it places the investment under the Japan-UK Memorandum of Cooperation on Fusion signed in June 2025, and says the investment comes at the start of the inaugural UK Fusion Week. UKAEA's head of materials science and engineering, Amy Gandy, is quoted describing the tritium breeder blanket as one of the most challenging components of a future fusion power station and the project's aim as replicating and irradiating a complete breeder blanket module. The release gives no site, date or partner facility for the irradiation itself.

DESNZ maps the fusion regulatory landscape for England and Wales

The Department for Energy Security and Net Zero published a 23-page policy paper on September 14 that sets out the main regulators and approvals that may apply across a fusion project's lifecycle in England and Wales, including planning, health and safety and environmental permitting, and points developers to further guidance. It restates the UK position that fusion facilities are regulated by the Health and Safety Executive and the Environment Agency (or devolved equivalents), and that in 2023 the UK legislated to confirm that fusion energy facilities are not nuclear installations for the purposes of the Nuclear Installations Act 1965. The paper says the 2026 fusion strategy committed the government to publish a roadmap setting out regulatory processes for developers, and presents itself, published alongside the draft National Policy Statement for fusion energy, EN-8, as showing how the UK continues to deliver that strategy; it says it does not replace project-specific regulatory advice.