Subscribe options

Select your newsletters:

Please enter your email address:

@

Your email address will only be used for the purpose of sending you the ITER Organization publication(s) that you have requested. ITER Organization will not transfer your email address or other personal data to any other party or use it for commercial purposes.

If you change your mind, you can easily unsubscribe by clicking the unsubscribe option at the bottom of an email you've received from ITER Organization.

For more information, see our Privacy policy.

News & Media

Latest ITER Newsline

  • Vacuum vessel repair | A portfolio

    Whether standing vertically in the Assembly Hall or lying horizontally in the former Cryostat Workshop now assigned to component repair operations, the non-conf [...]

    Read more

  • European Physical Society | ITER presents its new plans

    The new ITER baseline and its associated research plan were presented last week at the 50th annual conference of the European Physical Society Plasma Physics Di [...]

    Read more

  • Image of the week | The platform's quasi-final appearance

    Since preparation work began in 2007 on the stretch of land that was to host the 42-hectare ITER platform, regular photographic surveys have been organized to d [...]

    Read more

  • Cryopumps | Preparing for the cold tests

    Before being delivered to ITER, the torus and cryostat cryopumps are submitted to a  comprehensive series of factory acceptance tests. This is not sufficie [...]

    Read more

  • Fusion technologies | Closing a fusion schism

    Historically, inertial confinement and magnetic confinement approaches to fusion have been parallel, separate processes. The ITER Private Sector Fusion Workshop [...]

    Read more

Of Interest

See archived entries

Engineering

US to deliver "tough" electronics to ITER

ITER, a machine that will imitate the sun, will also mimic the sun's extreme environment: intense heat, strong magnetic fields and radiation. A team at US ITER has been toughening up critical components of ITER's vacuum system so they can withstand those harsh conditions.

The team involved in the development of radiation hardened electronics for US ITER includes (left to right): Frank Ivester, Shane Frank, Claudell Harvey, Nance Ericson and Kurt Vetter. Credit: ORNL (Click to view larger version...)
The team involved in the development of radiation hardened electronics for US ITER includes (left to right): Frank Ivester, Shane Frank, Claudell Harvey, Nance Ericson and Kurt Vetter. Credit: ORNL
Neutrons, an energetic by-product of the fusion reactions in the ITER device, will not travel in docile single file as they leave the plasma. When running at full power, ITER's plasma is projected to generate billions and billions of neutrons*, each one with 14.1 MeV (mega-electron-volts) of energy. Shielding reduces the neutron flux, but neutrons are sub-atomic in size and can scatter and slip between the atoms in concrete. The shielding reduces the number of neutrons to about a million per second per square centimetre outside the protective bioshield.

"Five hundred megawatts of plasma power will be a sustained radiation environment that the fusion community hasn't experienced before," says US ITER's Kurt Vetter. Vetter leads the teams for electron cyclotron and ion cyclotron heating transmission lines and for instrumentation and controls.

Vetter's group has been designing and building the radiation hardened ("rad hard," for short) electronics supporting ITER's vacuum auxiliary system. The electronics will be mounted at 68 locations just outside a protective bioshield to monitor the vacuum system for leaks and other potential issues.

US ITER engineers are not the first to face this problem. Aviation and aerospace engineers need to design around the effects of cosmic radiation in the upper atmosphere and space. On Earth, numerous smaller fusion devices have contended with neutron-yielding plasmas. But radiation from those experiments is orders of magnitude smaller than what ITER will generate.  

Neutrons, while short-lived, are a source of both direct and indirect radiation immediately around the tokamak. ITER will restrict access to this area and further protects staff and instrumentation with a 3.2-metre-thick concrete bioshield. But some of these neutrons, and the gamma rays they spawn when interacting with the cooling water around the tokamak, can still threaten nearby equipment.

Consequently, sensitive components need to be rad hard—designed and built with years of radiation exposure in mind. That includes the vacuum auxiliary system components being delivered by US ITER.

Their precise amount has been calculated. It is in excess of 1.77 multiplied by 10 followed by 27 zeros...

Continue reading the article on the US ITER website.



return to the latest published articles