Tokamak Energy and Oxford Sigma collaborate on the first American Society of Mechanical Engineers fusion power plant construction code and standards 

06 Sep 2023 | News

Tokamak Energy and Oxford Sigma joined forces to make key contributions to the first American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) for fusion energy power plant construction standards.  

This first publication of the ASME BPVC Section III (Rules for Construction of Nuclear Facility Components) Division 4 (Fusion Energy Devices) sets the framework and path to delivering commercial fusion energy. 

Tokamak Energy Inc, the West Virginia-based U.S. subsidiary of British company Tokamak Energy Ltd, was recently selected by the U.S. Department of Energy (DOE) for an award as part of its bold decadal vision for delivering commercial fusion. 

The DOE’s multimillion-dollar Milestone-Based Fusion Development Program was established to support private companies in bringing fusion energy toward technical and commercial viability. The new Division 4 within the Section III code published this summer is an important resource for fusion companies to design and construct future power plants. 

Tokamak Energy and Oxford Sigma, a fusion technology company, have contributed on the draft of the first volume of Division 4 since 2021. The collaboration supported Dr Thomas Davis, Oxford Sigma’s co-founder and CTO, to form and chair the Division 4 subcommittee titled ‘Special Working Group for Fusion Stakeholders’. The Group provides a platform to present the needs of the fusion stakeholder community in order to guide the development of the code. 

‘This big step forward will help future fusion energy power plants meet consistent industry standards. Importantly, it will reduce design risk and boost the supply chain on our mission towards delivering clean, secure and affordable fusion power in the 2030s. We are delighted to have contributed to this effort by working alongside Oxford Sigma to bring together key stakeholders across the U.S. fusion industrial community, and to kickstart the conversation about good practice in fusion power plant engineering, design and construction.’ 

~ Jack Astbury, Fusion Technology Manager, Tokamak Energy

‘It is great to see the publication of the first volume of Fusion Energy Devices construction code and standards after collaborating with Tokamak Energy for the past two years on defining the foundations for materials qualification routes and best practices in engineering design. This type of development in standards within fusion is the bedrock of enabling commercialisation of the ultimate energy source.’

~ Dr Thomas Davis, Chief Technology Officer, Oxford Sigma

The ASME BPVC provides the design and construction rules of boilers and pressure vessels worldwide, covering both nuclear and non-nuclear devices. The documents are written and maintained by chosen volunteers based on their technical expertise. Section III Division 4 is new to 2023, providing requirements for the construction of fusion energy devices.  

These requirements cover fusion energy-related components such as vacuum vessels, cryostats, superconducting magnet structures, and the interactions of these components. Related support structures, including metallic and non-metallic materials, containment or confinement structures, and in-vessel components, such as fusion-system piping, vessels, valves, pumps, and supports, are also covered. Additionally, the rules contain requirements for materials, design, fabrication, testing, examination, inspection, certification, and stamping. 

In connection to the newly published volume, Dr Davis presented its implications at the 23rd Symposium on Fusion Engineering Conference on “Fusion Codes & Standards ASME BPVC Section III Division 4” in Oxford in July. Dr Davis also authored a peer-reviewed paper titled “The need for codes and standards in nuclear fusion energy” in the special collection, “The emergence of Private Fusion Enterprises” in the Journal of Fusion Energy in May 2023. The article is available open access here

About Tokamak Energy  
Tokamak Energy is a leading global commercial fusion energy company based near Oxford, UK. We have an unrivalled track record designing and operating spherical tokamaks; the optimal route to commercial fusion energy.  

In addition to fusion energy, Tokamak Energy is recognised as the leader in High Temperature Superconductor (HTS) magnet design, numerical modelling, and prototyping. Our dedicated HTS magnet team, in collaboration with key manufacturing partners, is focussed on becoming the leading supplier of HTS magnets to multiple markets.   

The company, founded in 2009 as a spin-off from UK Atomic Energy Authority, currently employs a growing team of over 250 people with experts from the UK and around the world. It combines world leading scientific, engineering, industrial and commercial capabilities. The company has 70 families of patent applications and has raised $250 million, comprising $200m from private investors and $50m from the UK and US governments. Our US subsidiary, Tokamak Energy Inc, was established in 2019. Visit for more information. 

About Oxford Sigma 
Oxford Sigma is a Fusion Technology company with a vision to tackle energy security and climate change by accelerating the commercialisation of fusion energy. Our mission is to deliver materials technology, materials solutions, and fusion design services. Oxford Sigma aims to produce advanced materials technologies, agnostic to fusion approach, for the materials ecosystem. Our fusion core materials are engineered to enable longer term operations for fusion pilot plants, with the aim of roll out to the first-of-a-kind commercial power stations. Oxford Sigma is internationally recognised as a key fusion materials and technological leader. The company operates in the United States, United Kingdom, European Union, Canada, and Japan, with offices in the UK and USA. Our roots and headquarters are in Oxford, UK.

Get in touch at [email protected]