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Europe · UK · Founded 2009

Saturday, June 13, 2026

Tokamak Energy

Magnetic confinement — spherical tokamak

Strategic Analysis Compare this company
Confinement

Magnetic

Fuel Cycle

Deuterium-Tritium

Funding

≈ £250M cumulative

Timeline

Demonstration plant ~2030; commercial 2030s

Investor brief

Spherical tokamaks and the UK's de facto HTS magnet supplier

Executive Summary

Tokamak Energy is the UK's spherical-tokamak pioneer and the de facto HTS magnet supplier to the UK fusion programme. Its ST40 reached 100 million °C ion temperature in 2022; in 2024 it tested a 26.2 T HTS magnet at CERN — among the highest fields ever reached by an HTS demountable magnet. In 2025 it was named magnet systems partner for the UK STEP programme.

Strategic Thesis

Spherical geometry yields the highest β (plasma pressure / magnetic pressure) of any tokamak. Combined with HTS, this enables a much smaller, cheaper compact plant.

Technical & Economic Profile

Architecture class

Tokamak & Spherical Tokamak Vanguard

Read full class analysis

Most mature dataset in fusion. HTS REBCO magnets shrink reactor volume; D-T cycle exploits the highest nuclear cross-section at the lowest temperatures.

Reactor design

Magnetic / Spherical Tokamak (A ≈ 2.0)

Core tech focus

HTS REBCO magnets — 26.2 T tested at CERN (2024)

Key milestones

ST40 reached 100M °C ion temperature (2022). Demo plant ~2030.

How Tokamak Energy sits vs peers

Spherical-tokamak pioneer. ST geometry maximises β; combined with > 26 T HTS magnets, the architecture targets the highest power density in the class.

Class engineering bottlenecks

  • 14.1 MeV neutron flux degrades RAFM steel and tungsten armor above ~80 dpa, forcing periodic first-wall replacement.
  • Achieving a Tritium Breeding Ratio > 1.0 in compact geometry — especially on space-constrained spherical-tokamak center-posts — is unresolved.
  • REBCO tape suffers irreversible critical-current loss above 0.4% tensile strain; > 30 T fields generate GPa-class Lorentz forces requiring MP35N superalloy substrates and carbon-fiber cocoons.
  • Sudden plasma disruptions vaporise plasma-facing components — repair downtime is the single dominant LCOE variable per ARPA-E pyFECONs.

LCOE drivers

  • Disruption-driven capacity-factor losses (AI digital-twin control projected to cut NOAK LCOE 17–20%).
  • ⁶Li enrichment supply chain: ~100 t per plant at $5,000/kg can hit 80% of overnight capital cost.
  • Balance-of-plant (steam turbine, heat exchangers, cooling towers) dominates D-T capex.

Sourced from the 2026 Global Fusion Energy Comparison — triple-product thresholds, direct-energy-conversion architecture, materials limits, and the LCOE / Qecon framework.

Founding Team

Spun out from the UK's legendary Culham Centre for Fusion Energy, this elite trio pioneered the entire concept of the commercial spherical tokamak. Alan Sykes conducted the historical, foundational calculations showing that a cored-apple plasma shape dramatically increased efficiency, while Dr. Mikhail Gryaznevich managed world-class experimental operations. Complemented by Cambridge physicist and corporate strategist Dr. David Kingham, the founders proved that pairing spherical geometry with newly emerging High-Temperature Superconducting (HTS) magnets was the fastest, most compact path to a viable pilot plant in the United Kingdom.

Mikhail Gryaznevich

PhD in Plasma Physics, Ioffe Institute, Russia

Alan Sykes

MA in Physics, University of Oxford

David Kingham

PhD in Physics, University of Cambridge

View full founding team page

The Problem

Global electricity demand is entering an unprecedented growth phase driven by AI infrastructure, data centers, transport electrification, industrial decarbonization, water desalination, and advanced manufacturing. Solar suffers intermittency, wind capacity-factor variability, natural gas carbon emissions, conventional nuclear cost and deployment speed, and batteries energy-density and duration limits. The world requires a new source of clean, dispatchable baseload energy. Fusion represents the ultimate energy source — the challenge is making it commercially practical.

Compact Spherical Tokamak + HTS Magnets

Spherical tokamaks compress the donut into nearly a sphere, achieving the highest plasma β of any tokamak topology. Combined with HTS magnets, this enables a much smaller, cheaper compact plant.

ST40 — Plasma Performance Record

First privately-funded device to reach 100 million °C ion temperature.

ST80-HTS Demonstrator

Next-generation device validating HTS magnets in the spherical geometry.

HTS Magnet Business

Tokamak Energy's magnet division supplies the UK STEP programme and is positioning as a global HTS supplier.

Fuel Strategy

Deuterium-Tritium

Standard D-T fuel cycle.

Product Platform

ST40

Current research device with record plasma performance.

ST80-HTS

Next-generation HTS spherical tokamak demonstrator.

HTS Magnet Systems

Commercial HTS magnets for STEP and the broader fusion industry.

Energy Conversion

Category

Thermal (Rankine/Brayton)

Neutronicity

Neutronic (D-T)

Target efficiency

33–40% electrical

Deuterium-tritium fusion releases ~80% of its energy as 14.1 MeV neutrons, which deposit their kinetic energy in a surrounding blanket. The heat drives a conventional steam (Rankine) or supercritical-CO₂ (Brayton) turbine.

Conversion chain

  1. 1D-T plasma
  2. 214.1 MeV neutrons (80%) + 3.5 MeV alpha (20%)
  3. 3Neutrons → lithium-bearing blanket (heat + tritium breeding)
  4. 4Heat → steam/CO₂ turbine → electricity

The most thoroughly understood fusion fuel cycle, highest cross-section at achievable temperatures, and proven back-end engineering (steam turbines are 19th-century technology). Trade-offs: neutron-induced materials damage, tritium handling, ~33–40% Carnot-limited efficiency.

Economic Vision

Twin-track business model: a commercial HTS magnet business generating revenue today, while the spherical-tokamak power-plant program matures over the 2030s.

Vision

Spherical tokamaks as the most compact magnetic-confinement pathway to commercial fusion.

Mission

Deliver compact spherical-tokamak fusion power and supply the magnets the rest of the industry needs.

Engineering Bottlenecks

  • Inboard centre-post neutron shielding (no room for thick blanket)
  • Disruption mitigation in compact ST geometry

Milestone Timeline

  1. 2022

    ST40 reached 100M °C ion temperature

  2. 2024

    26.2 T HTS magnet test at CERN

  3. 2025

    Named magnet systems partner for UK STEP

The description above reflects Tokamak Energy's publicly stated technology goals, roadmap and architecture. Many elements — particularly net-energy gain at scale, advanced fuel cycles, and grid-relevant economics — remain ambitious objectives that have not yet been demonstrated commercially anywhere in the fusion industry. Forward-looking statements should be treated as engineering targets, not certainties.

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Citations & Sources

Academic & financial rigor
  1. [01]

    ST40 achieves 100 million °C

    Tokamak Energy · 2022

  2. [02]

    26.2T HTS magnet at CERN

    Tokamak Energy · 2024

  3. [03]

    The Global Fusion Industry in 2025

    Fusion Industry Association · Jul 2025

  4. [04]

    Company disclosures and press releases

    Tokamak Energy

  5. [05]

    Peer-reviewed plasma physics literature

    Journal of Plasma Physics / Nuclear Fusion