Amentum and Kyoto Fusioneering sign MoU on fusion plant engineering across UK, Japan and US

Amentum has signed a memorandum of understanding with Japanese fusion technology company Kyoto Fusioneering to pursue joint work on fusion energy programmes in the United Kingdom, Japan and the United States, the two companies said.

Amentum announced the agreement on 3 November from Oak Ridge, Tennessee. Kyoto Fusioneering (KF) published its own version of the announcement the following day.

According to the Nuclear Industry Association, which carried the release, the agreement sets up a framework for cooperation between the two firms and they intend to pursue joint opportunities across major public and private fusion programmes. No contract value, programme or timetable was given.

Mark Whitney, president of Amentum's Energy and Environment business, said: "By combining Amentum's capabilities with Kyoto Fusioneering's advanced fusion technologies, we can help address the engineering and delivery challenges required to move fusion from experimental systems towards commercially viable power plants."

What each side brings

Amentum said it would contribute technology-agnostic fusion engineering capability, covering systems engineering, plant integration, nuclear safety, digital engineering and programme delivery.

KF's contribution is its confinement-agnostic fuel cycle, breeding blanket and plasma heating systems, together with its experience of integrating them into fusion plant designs, the release said.

The partners also plan to explore combining fusion engineering with digital and AI-driven engineering and programme delivery tools. The companies said this could optimise design cycles and improve predictive performance.

Kiyoshi Seko, president and chief operating officer of Kyoto Fusioneering, said: "Amentum brings nuclear engineering and program delivery experience at the scale fusion programs will need as they move toward construction."

The UK connection

Both companies already work alongside the UK Atomic Energy Authority (UKAEA) at Culham.

Amentum said it provides engineering design services for UKAEA programmes and has staff embedded in client teams at UKAEA's Culham Campus. UKAEA is also funding Amentum research into the properties of lithium, a material relevant to breeding fusion fuel, and the company said it has taken part in UKAEA's Fusion Industry Programme since the programme began. Its heritage firms supported the Joint European Torus experiment.

KF said it established its UK presence in 2021 and has worked with UKAEA since then. In an October 2026 announcement the company said it is expanding its Culham-based team at its UK subsidiary, Kyoto Fusioneering UK, and framed its UK activity as falling under the Japan-UK Memorandum of Cooperation on Fusion signed in June 2025.

The UK and Japanese governments confirmed that partnership on 19 June 2025. According to the Department for Energy Security and Net Zero, the memorandum covers research and development, regulation, and skills and workforce, and the UK government said its international collaborations are intended to help commercialise fusion energy as quickly as possible.

The US footing

KF's US position rests on a public-private partnership with Oak Ridge National Laboratory (ORNL), which anchors a strategic partnership between the US Department of Energy and the company.

ORNL said the two organisations plan to develop experimental infrastructure for testing tritium breeding blanket systems, with the planned UNITY-3 breeding blanket test facility to be sited at the laboratory.

The companies said Japan's national fusion strategy and its growing investment in private-sector demonstration projects create new opportunities for the collaboration.

The companies

Kyoto Fusioneering was founded in 2019 as a spinout from Kyoto University and is based in Tokyo and Kyoto. Descriptions of its overseas footprint differ: Amentum's release lists subsidiaries in the United States, the United Kingdom and Germany, while ORNL describes subsidiaries in the US, the UK, the European Union and Canada.

Amentum is headquartered in Chantilly, Virginia, is listed on the New York Stock Exchange under the ticker AMTM, and has about 50,000 employees in more than 70 countries.