US and UK partner with Tokamak Energy on ST40 upgrade

The energy departments of the US and UK governments are to partner with Tokamak Energy for a USD52 million upgrade of the ST40 fusion facility, which will coat its inner wall with lithium.

The US Department of Energy, the UK's Department of Energy Security and Net Zero and Tokamak Energy will equally share the funding of the five-year programme which is intended to advance research and knowledge to help development of future fusion power plants.

Tokamak Energy says fusion requires conditions where particles have to be hot enough and dense enough and retain their heat for long enough to release net energy and "the goal of this work is to enable fusion conditions with good confinement that is compatible with sustainment for long durations in a future fusion pilot plant, by coating the inner wall of the ST40 device with the element lithium".

Last year the two energy departments agreed a fusion strategic partnership, with a key goal being to establish shared access to and development of facilities for fusion research and development. The new agreement will mean researchers at universities and national laboratories in both countries will be able to benefit from the research carried out at the ST40 tokamak (a tokamak is a machine that confines a plasma using magnetic fields in a doughnut shape) with the facility upgrade expected to be operational in 2027.

The ST40, which uses applied magnetic fields to confine plasma, is privately owned and valued at more than USD100 million, the US Department of Energy said. Tokamak Energy, in a previous partnership with the Princeton Plasma Physics Laboratory and Oak Ridge National Laboratory achieved temperatures in ST40 which were six times hotter than the sun, becoming the first private firm to reach a plasma temperature of 100 million degrees Celsius.

Both laboratories will be assisting in the ST40 upgrade with their expertise, Princeton on lithium coatings and Oak Ridge on deploying pellet fuelling capabilities.

Princeton Plasma Physics Laboratory Director Steven Cowley said: "PPPL pioneered the use of lithium coatings in fusion back in the 90s. We’ve since refined our understanding of the radical confinement improvements these coatings can enable, and we’re excited to see this expertise leveraged by and advanced in collaboration with the private fusion industry."

Warrick Matthews, CEO of Tokamak Energy, said: "Our high field spherical tokamak ST40 has achieved impressive results in recent years, and we are thrilled to commence ST40’s new mission through this strong public private partnership. This programme will advance fusion science and technology for spherical tokamaks and the industry more broadly, in pursuit of a common goal to deliver fusion power."

Jean Paul Allain, the Department of Energy Office of Science Associate Director for Fusion Energy Sciences, said: "We’re eager to see this new capability on ST40. What excites me most is the possibility of deploying our university and national lab scientists to leverage this new capability through our Private Facility Research programme. It’s these publicly supported scientists, collaborating with their colleagues at private facilities, who drive the major advances needed in this field to support a competitive US fusion power industry."

Geraldine Richmond, US Under Secretary for Science and Innovation, said: "These new investments will strengthen our partnerships with the private sector and our international allies. Each partner stands to gain significantly more than the funds committed."

Kerry McCarthy, UK Minister for Climate, said: "This strategic partnership is ... crucial to develop this new and exciting technology, and bring it into use quicker."

Background

Fusion has no carbon emissions and has abundant and widespread fuel resources. Fusion research aims to copy the process which powers the sun - when light atomic nuclei fuse together to form heavier ones, a large amount of energy is released. To do this, fuel is heated to extreme temperatures, at least 10 times hotter than the centre of the sun, forming a plasma in which fusion reactions take place. A commercial power station will use the energy produced by fusion reactions to generate electricity. The fundamental challenge, being addressed in a variety of ways, is to achieve a rate of heat emitted by a fusion plasma that exceeds the rate of energy injected into the plasma.

Tokamak Energy was spun out of the UK's Atomic Energy Authority in 2009. It announced in February last year it was to build a prototype spherical tokamak, the ST80-HTS, at the UKAEA's Culham Campus, near Oxford, England, by 2026 "to demonstrate the full potential of high temperature superconducting magnets" and to inform the design of its fusion pilot plant, to demonstrate the capability to deliver electricity into the grid in the 2030s, with the aim of globally deployable 500-megawatt commercial plants.

And in October it gave first details of a high-field spherical tokamak plant "capable of generating 800 MW of fusion power and 85 MW of net electricity" as part of the USA's Bold Decadal Vision for Commercial Fusion Energy programme. It said "initial designs are for the tokamak to have an aspect ratio of 2.0, plasma major radius of 4.25 metres and a magnetic field of 4.25 Tesla, as well as a liquid lithium tritium breeding blanket". It will include a new generation set of high temperature superconducting magnets "to confine and control the deuterium and tritium hydrogen fuel in a plasma many times hotter than the centre of the sun".