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 1605

"We visit Barcelona, one of the smartest cities in the world, to find out what makes it so special. What does it look like and what is the future?"

E&T jobs

  • Senior Development Engineer, Electronics

    Premium job

    Helmet Integrated Systems / Gentex Corporation
    • Letchworth Garden City, Hertfordshire
    • Competitive

    We are an innovative, robust and fast growing business, whose main focus is to deliver continues improvement to existing products and offer new sol..

    • Recruiter: Helmet Integrated Systems / Gentex Corporation

    Apply for this job

  • Smart Grid Research Engineer

    Premium job

    University of Strathclyde
    • Cumbernauld, Glasgow
    • Grade: 6/7* £26,537 - £37,768*

    Work as part of a growing dynamic team on a wide range of technical projects with particular emphasis on experimental validation and testing

    • Recruiter: University of Strathclyde

    Apply for this job

  • Electrical Asset Specialist

    Affinity Water
    • Hatfield, Hertfordshire

    Responsible for updating and writing electrical engineering standards, approved codes of practice and safe systems of work

    • Recruiter: Affinity Water

    Apply for this job

  • Senior Electronics Engineer

    York Instruments
    • York, North Yorkshire

    Senior electronics engineer to work as part of a team developing an MEG imaging system; working with the engineering team and external contractors.

    • Recruiter: York Instruments

    Apply for this job

  • Manufacturing Engineer - Circuit Card Assembly

    MBDA
    • Lostock Junction
    • Competitive Salary & Benefits

    What’s the opportunity?   Manufacturing UK is an integral part of the Operations Directorate whose principal mission is to ensure that MBDA’s deliverable commitments are met...

    • Recruiter: MBDA

    Apply for this job

  • High Voltage Engineer

    Premium job

    Essex X-Ray & Medical Equipment
    • Great Dunmow, Essex

    This High Voltage Engineer will provide design leadership for high voltage cable assemblies up to one megavolt.

    • Recruiter: Essex X-Ray & Medical Equipment

    Apply for this job

  • Team Leader - Flank Arrays

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

    Team Leader - Flank Arrays Would you like to work in a unique role within the construction of the Astute Class submarines? We currently have a vacancy for a Team Leader - Flank Arrays at our site in Barrow-in-Furness. As a Team Leader - Flank Arrays, you

    • Recruiter: BAE Systems

    Apply for this job

  • Electronics and Software Engineer

    Copley Scientific Ltd
    • Nottingham
    • circa £35,000 per annum + bonus

    Develop new test equipment for the pharmaceutical industry. Good opportunities to grow and develop. Successful family-owned and managed business.

    • Recruiter: Copley Scientific Ltd

    Apply for this job

  • Bridge Test Facility Manager

    BAE Systems
    • Shropshire, Telford, England
    • Negotiable

    Bridge Test Facility ManagerWe currently have a vacancy for a Bridge Test Facility Manager at our site in Telford with our Land UK business.As the Bridge Test Facility Manager, you will be part of our Test & Trials team, working closely with the Mili

    • Recruiter: BAE Systems

    Apply for this job

  • Intelligent Transport Systems Engineer - Highways Technology

    Premium job

    Mott MacDonald
    • Birmingham, West Midlands

    Our transport technology team in Birmingham is currently growing a highly skilled and customer-focused team to...

    • Recruiter: Mott MacDonald

    Apply for this job

More jobs ▶

Subscribe

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

Subscribe to E&T