JET scientists melt tokamak for the sake of ITER

23 August 2013
By Tereza Pultarova
Mobile version
Share |
A drop of molten tungsten captured moving away from the area of hottest plasma during an experiment in the JET tokamak

A drop of molten tungsten captured moving away from the area of hottest plasma during an experiment in the JET tokamak

The team constructing the International Thermonuclear Experimental Reactor (ITER) requested their colleagues operating UK’s tokamak JET to expose the machine to extreme loads to find the best materials for ITER’s plasma facing wall.

“There was a slight worry we would see uncontrolled, firework-like splashes of molten metal and that might affect subsequent experiments,” said Dr Gilles Arnoux, one of the scientific coordinators of the experiment. “But it was a smooth melt; the plasma didn’t seem to notice. I was surprised at how little impact it had.”

The tests at JET involved subjecting a small area of a deliberately misaligned tungsten wall tile to regulated bursts of turbulent plasma.  During the experiment, the exposed tile was heated up to peak temperatures of 3422° C, to allow the researchers assessing what affect molten tungsten might have on the plasma.

The team’s biggest concern was the melt event could result in contamination of the hydrogen-based plasma with tungsten, which would cause disruption and uncontrolled energy dump of the plasma. Such situation would lead to further melting of the surface, which might become detrimental to the equipment's safety.

However, the molten material moved smoothly to one end of the tile during the experiment, forming a droplet that grew with each additional plasma pulse. Surprisingly, the droplet did not run downwards, but moved away from the hottest part of the plasma instead, due to magnetic forces inside the tokamak.

“It has been a great success and has achieved what it set out to do,” said Dr Richard Pitts, the leader of ITER’s Divertor and Plasma Wall Interactions section, who joined the JET team during the experiment.

“It seems that we can broadly understand what we have seen on the basis of complex computer simulations describing the melt dynamics and thus our confidence is increased in the extrapolations we make for the behaviour to expect on ITER,” he said, adding the results are extremely significant for the ITER team, currently considering the use of tungsten for the construction of ITER.

To achieve fusion inside a tokamak, gas needs to be heated to more than one hundred million ° C, at which temperature it turns into sun-like plasma. Of particular concern to researchers are bursts of turbulence on the edge of the plasma similar to solar flares, which can momentarily inflict heat loads far greater than a blow torch on small areas of the tokamak wall.

The experiments at JET, which is currently the world’s biggest operating tokamak, will continue until mid-2014.

Latest Issue

E&T cover image 1607

"As the dust settles after the referendum result, we consider what happens next. We also look forward to an international summer of sport."

E&T jobs

  • Chair in Integrated Sensor Technology

    The University of Edinburgh
    • Edinburgh, City of Edinburgh

    The University of Edinburgh is one of the world’s top 20 institutions of higher education.....

    • Recruiter: The University of Edinburgh

    Apply for this job

  • Principal Electrical Engineer - Power

    BAE Systems
    • Bristol, England / Cumbria, Barrow-In-Furness, England
    • Negotiable

    Principal Electrical Engineer - Power Join our Electrical Power team and help design the self-contained generation and distribution system for the Successor submarine - a new generation of submarine designed to carry the UK's independent nuclear deterrent

    • Recruiter: BAE Systems

    Apply for this job

  • Operations Supervisor (Mechanical/Electrical/Instrumentation)

    National Grid
    • England, Cambridgeshire
    • £33000 - £39000 per annum

    Operations Supervisor - (Mechanical/Electrical/Instrumentation) Salary: Circa £33k - 39k dependant on experience + vehicle and great additional benefits (share scheme, pension, potential bonus).Location: Wisbech - Cambridgeshire We currently have an excit

    • Recruiter: National Grid

    Apply for this job

  • Lead NDT Trainer

    BAE Systems
    • England, Lancashire
    • Competitive package

    Would you like to be involved with training UK and international teams in Non Destructive Inspection (NDI) to support the in service fleet (Typhoon Tornado, and Hawk)?

    • Recruiter: BAE Systems

    Apply for this job

  • Systems Design - Emerging Portfolio

    • Bristol
    • Competitive Salary & Benefits

    What?s the opportunity?   There are fantastic opportunities in Systems Design for engineers to work within Future Systems. These are highly visible, fast paced roles, in...

    • Recruiter: MBDA

    Apply for this job

  • Metering Engineer

    Department for Business, Innovation and Skills
    • Teddington, United Kingdom
    • £24,109 - £27,961 plus EO Electronics PE of £8,090.00

    We are now looking for a Metering Engineer to deliver RD’s In-Service Testing (IST) scheme for gas and electricity meters.

    • Recruiter: Department for Business, Innovation and Skills

    Apply for this job

  • Head of Operational Estates

    Premium job

    The Shrewsbury and Telford Hospital NHS Trust
    • Shrewsbury, Shropshire
    • £46,625 to £57,640 per annum

    As an experienced Estates Manager, you will play a key role in helping to shape the future of the Estates service.

    • Recruiter: The Shrewsbury and Telford Hospital NHS Trust

    Apply for this job

  • Assistant Professor (Tenure Track) of Smart Building Solutions

    Premium job

    ETH Zurich
    • Zurich, Canton of Zürich (CH)

    The successful candidate is expected to develop a strong and visible research programme in the area of control and diagnostics of building systems

    • Recruiter: ETH Zurich

    Apply for this job

  • Process Controls Leader

    Premium job

    Phillips 66
    • Humber Refinery, South Killingholme, North Lincolnshire DN40 3DW
    • £60k - 75k plus extensive Compensation and benefits package, dependent upon experience

    Experienced Process Control Leader providing leadership and technical support for Oil Refinery. Extensive Compensation and benefits package.

    • Recruiter: Phillips 66

    Apply for this job

  • Regional Technical Support Manager

    Premium job

    • Warwick, Warwickshire

    You will be required to lead the regional Customer Services strategy and resources to maximise Customer satisfaction.

    • Recruiter: Siemens

    Apply for this job

More jobs ▶


Choose the way you would like to access the latest news and developments in your field.

Subscribe to E&T