Ex-UKAEA fusion scientists go private

21 February 2011

Fusion research company Tokamak Solutions has secured £170,000 of equity investment from Sir Martin and Lady Audrey Wood, the Rainbow Seed Fund, Oxford Instruments plc and investor members of the Oxford Early Investments network.

The funding will enable Tokamak Solutions to complete the design of its novel fusion neutron source - a super compact tokamak. Applications for the new technology range from the clean-up of nuclear waste, which could make safe nuclear power a reality, to the production of medical isotopes used in the diagnosis and treatment of diseases such as cancer and, in the longer term, as part of a zero carbon method for large scale hydrogen production.

The company has also just been awarded a EUR 110,000 contract from ITER, the next generation international fusion energy research reactor, to advise on diagnostics for measuring neutron emission and fusion power.

Fusion scientists around the world are designing methods to harness fusion as an energy source that typically involve the construction of huge, multi-billion pound facilities. The Tokamak Solutions team located at Culham, Oxfordshire is focused on creating a super compact, but powerful, fusion neutron source and has already filed patent applications for the initial design of its tokamak.

The concept of ‘fusion for neutrons’, the basis of the company’s technology, is the brainchild of Dr Mikhail Gryaznevich and Alan Sykes, who have worked on fusion research at Culham for 20 years.

They realised the success they had achieved with colleagues at Culham in creating two ground-breaking spherical tokamaks held the key to unlocking the potential of fusion neutron sources. In late 2009, they co-founded Tokamak Solutions with Dr David Kingham, former managing director of Oxford Innovation, who helped them formulate a business strategy to commercialise the technology.

Alan Sykes, technical director at Tokamak Solutions, said: “The fusion process produces an abundance of neutrons and by using the spherical tokamak this can be done very efficiently. This means that a fusion neutron source, with a wide variety of applications, can be realised on a much smaller scale than a fusion energy source of the ITER type.”

Dr Kingham, now chief executive of Tokamak Solutions, said: “We are delighted to have secured the investment we need to progress the development of this bold new technology. Our initial focus is on the plasma physics and neutron research markets and our new group of investors has already provided significant added value in addition to their investment. For example, Oxford Instruments has advised on potential applications in relation to superconducting magnets while the Rainbow Seed Fund has assisted with introductions to potential users of neutrons.”

Beyond the initial development stage, Tokamak Solutions’ fusion neutron source offers a viable way to clean up nuclear waste. Neutron bombardment can potentially deal with all radioactive nuclear waste, but one of the most promising applications lies in using neutrons to destroy the ‘minor actinides’ that are particularly problematic for burial.

Dr Gryaznevich, chief scientific officer at Tokamak Solutions, explained: “Burying minor actinides is expensive and risky as they undergo fissile decay over thousands of years, releasing heat and radioactive fragments, making them difficult to contain. During the past 30 years, many scientific papers have been written about the potential transmutation of minor actinides, but our super compact fusion neutron source is the first system based on currently available technology with the potential to produce the neutrons required for this clean-up.”

Additional applications for fusion neutron sources include: production of medical isotopes - where there are currently worldwide shortages; scientific research - where there is significant unmet demand; and in the testing of materials components for future fission and fusion energy reactors - where international facilities currently fall short of requirements. In the longer term, fusion neutron sources may prove valuable as part of an efficient, zero carbon method for large scale hydrogen production and as the core of a fusion-fission hybrid (or sub-critical) reactor that will breed its own fuel and destroy its own waste.

About spherical tokamaks

A tokamak uses a magnetic field to confine a plasma in the shape of a torus (doughnut). Experimental research of tokamak systems began in 1956 in Kurchatov Institute, Moscow by a group of Soviet scientists led by Lev Artsimovich.

In order to obtain sufficient fusion energy to exceed the power input required to create the magnetic field and heat the plasma, conventional tokamaks have to be very large - JET (Joint European Torus) at Culham and ITER, under construction at Cadarache, France, are huge, impressive feats of engineering.

The spherical tokamak, introduced in the 1970s, is a low aspect ratio version of a conventional tokamak. The first demonstration of a spherical tokamak was provided by the START device which was operational at the Culham Laboratory from 1990 to 1998. START was a small tokamak that only had a diameter of only one metre but it achieved world record efficiency for the amount of plasma that can be held by a given magnetic field.

During the last ten years, research on more than 15 small and medium sized spherical tokamaks, built to a simple design, has yielded excellent results and high reliability. Tokamak Solutions has created an enhanced design that will enable the use of spherical tokamaks as powerful fusion neutron sources.

Existing designs for fusion neutron sources are expensive to build and operate and are unreliable. Tokamak Solutions has overcome these problems by designing a smaller super compact fusion neutron source with an overall diameter of two metres that can provide megawatt level neutron output while operating at modest plasma performance.

This breakthrough has been achieved by harnessing the effectiveness of beam-plasma fusion.

Instead of requiring a large, ultra-hot plasma to produce fusion neutrons, the super compact fusion neutron source designed by Tokamak Solutions generates neutrons by the simpler method of injecting a high energy beam into a ‘warm’ plasma of modest size.

A feature of the Tokamak Solutions design is that physics demands (such as energy confinement and plasma elongation) and engineering constraints (such as wall and divertor loads) are within those already established on spherical tokamaks or on the ITER design. The plasma current is relatively low at 1.5MA, although the toroidal field of 1.5Tesla is substantially higher than presently employed on spherical tokamaks - this factor providing a major improvement in performance.

The design features novel techniques of plasma initiation, a particular problem with spherical tokamaks, where the compact size prohibits shielding to protect a central current-inducing solenoid. These novel techniques are based on the unique experience of Tokamak Solutions technical experts gained from their work on the pioneering START and MAST spherical tokamaks at Culham Centre for Fusion Energy, Oxfordshire.

Modelling shows that modest Neutral Beam Injection (NBI) power of 6-8 mega watts at high energy can both sustain the plasma current and produce megawatt level neutron output dominated by beam-plasma fusion. The low values (compared to other neutron source designs) of NBI power, plasma current and field ensure that the super compact fusion neutron source designed by Tokamak Solutions has significantly lower construction and operating costs.

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