STEP Fusion - Seeking a Cryogenics System Partner

Fusion energy is often referred to as the ultimate source of energy for mankind. Spherical Tokamak for Energy Production (STEP) Fusion is the UK’s flagship fusion power plant programme. UK Fusion Energy (Ltd), a subsidiary of UK Atomic Energy Authority, has been created with the purpose to deliver STEP Fusion.  Ultimately, UKFE's mission is to build a prototype fusion energy plant, targeting 2040, and develop a path to commercial viability of fusion.
STEP Fusion relies on a spherical tokamak at the very heart of the power plant. In this tokamak, a burning plasma enables fusion to occur via the collision of hydrogen isotopes. This plasma is confined using superconducting magnets. The very nature of the tokamak design and the management of the fusion specific fuel requires specific cryogenic temperatures and a significant amount of cryogens to enable operations. In turn this creates a distinct need for large and complex cryogenic infrastructure.
The STEP Fusion prototype power plant presents a cryogenic engineering challenge of exceptional scale and complexity. To support net electrical power generation, the cryogenic system must provide approximately 70 kW of equivalent refrigeration at 4.5 K to superconducting magnets, thermal shields, fuel-cycle equipment and other cryogenic users. The supply of cryogens is managed through a number of key sub systems, namely the cryogenic plant which is the ultimate source of the cryogens, and the cryo-distribution system, which will deliver the cryogens to the users.
The cryogenic plant[1] will be one of the largest globally, alongside CERN and ITER. The cryogenic plant will in itself, be more complex than other such large installations, as it must support large cryogenic loads at multiple temperatures.
The cryo-distribution[2] system must supply helium across multiple temperature levels, serve a large number of geographically distributed interfaces and accommodate transient loads associated with plasma operation, magnet ramping, and cryopump operations.
Controlling the resulting parasitic electrical demand of the cryogenic systems while maintaining availability, operational flexibility and equipment protection is fundamental to the technical and commercial viability of STEP Fusion.
To support the next phase of development, UKFE is seeking an industrial partner to contribute specialist cryogenic engineering and delivery capability. This partner would be responsible for the ultimate delivery of the cryogenic systems; from initial preliminary design to commissioning and operations handover. Initial funding is anticipated to support design development and technical risk-reduction activities through to 2029, and subject to future programme and funding approvals, the partnership would continue towards STEP Fusion operations around 2040.
 
ACKNOWLEDGEMENTS: This work has been funded by STEP Fusion, a major technology and infrastructure programme led by UK Fusion Energy Ltd (UKFE), which aims to deliver the UK’s prototype fusion power plant and a path to commercial viability of fusion.

[1] D.M. Aliaga et al 2025 IOP Conf. Ser.: Mater. Sci. Eng. 1327 012012
 
[2] D. M. Aliaga et al 2026 IOP Conf. Ser.: Mater. Sci. Eng. 1344 012094

Keywords
STEP|Fusion|Powerplant|Distribution|Refrigeration