Tokamak Energy’s pre-concept design for a fusion power plant: an overview of ST-E1
7 affiliations
- 1Tokamak Energy Ltd
- 2Princeton Plasma Physics Laboratory
- 3Oak Ridge National Laboratory (ORNL)
- 4Idaho National Laboratory (INL)
- 5Savannah River National Laboratory (SRNL)
- 6Columbia University
- 7Tokamak Energy Inc
Abstract
Climate change and rapidly rising energy demand, driven in part by artificial intelligence and data-centre growth, create an urgent need for stable, low-carbon, and abundant power. Fusion is a promising long-term solution, yet its commercialisation faces a fundamental paradox in today’s investment environment: pilot plants are essential to de-risk physics, engineering, and operations, but their limited lifetime energy output and high upfront costs make them difficult to finance. This paper presents Tokamak Energy’s response: ST-E1, a pre-concept design for a low-aspect-ratio tokamak power plant engineered specifically to overcome this challenge. ST-E1 is designed from the outset for phased operation—pilot and commercial phases, with an upgrade phase in between—with emphasis on commercial viability, maintainability, nuclear engineering, modularity, and upgradability. A key design principle is the deliberate separation of long-lived assets, such as the magnet cage and vacuum vessel, from replaceable in-vessel systems. This provides an attractive and credible investment approach to generate operational data and de-risk key technologies while preserving most capital-intensive assets for later commercial phases. The architecture supports continuous optimisation toward high net electric power (targeting 800–1000 MW net electric), a normalised capital expenditure of $ 12–14k/kW of net electric power, and high availability (targeting > 80 % ). A tokamak core with a 5 m major radius, aspect ratio of 2.3, and on-plasma axis toroidal field of 5.25 T was selected to meet these objectives. This paper summarises the ST-E1 design philosophy, principal features, and development methodology. It introduces a Focus Collection of 11 papers detailing the pre-concept design of the entire tokamak and corresponding plant.
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BibTeX
@article{willis2026tokamak,
title = {{Tokamak Energy’s pre-concept design for a fusion power plant: an overview of ST-E1}},
author = {J. Willis and Steven McNamara and E.N.J. Maartensson and Jack O. Astbury and Emrah Yıldırım and N. Hinton and C.L. Wilson and X. Zhang and J.W. Berkery and L. R. Baylor and Masashi Shimada and H. Flynn and Andrew Oakleigh Nelson and S. Abouelazayem and А. И. Алиева and T. Anderson and J. Benayas and L. Black and Marcus Borscz and Matthew Bristow and S. Brown and Patrick Bunting and Alasdair Burchill and K. Chandrasekhar and P. Cheema and O. Danisworo and A. Yu. Dnestrovskij and A V Dudkovskaia and J. England and J. Fowler and V. Godhani and E. Guise and Sandeep Irukuvarghula and D. James and Filip Janky and G.S. Kamal and Jisung Kang and M. Kruip and Abhishek Kumar and Vivian Y.S. Lee and Samara M. Levine and J. Lima and Nicolas Lopez and I. Loughran and F. Malinowski and Chris Marsden and L. Mateescu and A.F.P. McAdam and Sergei Yu. Medvedev and M. Michalopoulou and Mohamed Khalid Elsharif Mohamed and Jonathan David Naish and G. Naylor and Daniel O’Dea and J.R. Pickles and R. Pocock and Matthew Robinson and M. Romanelli and S. Romanelli and A. Scarabosio},
journal = {Nuclear Fusion},
year = {2026},
month = jul,
doi = {10.1088/1741-4326/ae5545},
url = {https://doi.org/10.1088/1741-4326/ae5545},
note = {CC BY},
}
RIS
TY - JOUR
TI - Tokamak Energy’s pre-concept design for a fusion power plant: an overview of ST-E1
AU - J. Willis
AU - Steven McNamara
AU - E.N.J. Maartensson
AU - Jack O. Astbury
AU - Emrah Yıldırım
AU - N. Hinton
AU - C.L. Wilson
AU - X. Zhang
AU - J.W. Berkery
AU - L. R. Baylor
AU - Masashi Shimada
AU - H. Flynn
AU - Andrew Oakleigh Nelson
AU - S. Abouelazayem
AU - А. И. Алиева
AU - T. Anderson
AU - J. Benayas
AU - L. Black
AU - Marcus Borscz
AU - Matthew Bristow
AU - S. Brown
AU - Patrick Bunting
AU - Alasdair Burchill
AU - K. Chandrasekhar
AU - P. Cheema
AU - O. Danisworo
AU - A. Yu. Dnestrovskij
AU - A V Dudkovskaia
AU - J. England
AU - J. Fowler
AU - V. Godhani
AU - E. Guise
AU - Sandeep Irukuvarghula
AU - D. James
AU - Filip Janky
AU - G.S. Kamal
AU - Jisung Kang
AU - M. Kruip
AU - Abhishek Kumar
AU - Vivian Y.S. Lee
AU - Samara M. Levine
AU - J. Lima
AU - Nicolas Lopez
AU - I. Loughran
AU - F. Malinowski
AU - Chris Marsden
AU - L. Mateescu
AU - A.F.P. McAdam
AU - Sergei Yu. Medvedev
AU - M. Michalopoulou
AU - Mohamed Khalid Elsharif Mohamed
AU - Jonathan David Naish
AU - G. Naylor
AU - Daniel O’Dea
AU - J.R. Pickles
AU - R. Pocock
AU - Matthew Robinson
AU - M. Romanelli
AU - S. Romanelli
AU - A. Scarabosio
PY - 2026
DA - 2026/07/10
JO - Nuclear Fusion
DO - 10.1088/1741-4326/ae5545
UR - https://doi.org/10.1088/1741-4326/ae5545
AB - Climate change and rapidly rising energy demand, driven in part by artificial intelligence and data-centre growth, create an urgent need for stable, low-carbon, and abundant power. Fusion is a promising long-term solution, yet its commercialisation faces a fundamental paradox in today’s investment environment: pilot plants are essential to de-risk physics, engineering, and operations, but their limited lifetime energy output and high upfront costs make them difficult to finance. This paper presents Tokamak Energy’s response: ST-E1, a pre-concept design for a low-aspect-ratio tokamak power plant engineered specifically to overcome this challenge. ST-E1 is designed from the outset for phased operation—pilot and commercial phases, with an upgrade phase in between—with emphasis on commercial viability, maintainability, nuclear engineering, modularity, and upgradability. A key design principle is the deliberate separation of long-lived assets, such as the magnet cage and vacuum vessel, from replaceable in-vessel systems. This provides an attractive and credible investment approach to generate operational data and de-risk key technologies while preserving most capital-intensive assets for later commercial phases. The architecture supports continuous optimisation toward high net electric power (targeting 800–1000 MW net electric), a normalised capital expenditure of $ 12–14k/kW of net electric power, and high availability (targeting > 80 % ). A tokamak core with a 5 m major radius, aspect ratio of 2.3, and on-plasma axis toroidal field of 5.25 T was selected to meet these objectives. This paper summarises the ST-E1 design philosophy, principal features, and development methodology. It introduces a Focus Collection of 11 papers detailing the pre-concept design of the entire tokamak and corresponding plant.
SN - 0029-5515
SN - 1741-4326
ER -