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

  • Gravity supports | More than just pedestals

    In the ITER Tokamak, components with the simplest of missions—like supporting a very heavy load—are pieces of highly sophisticated technology. Take the gravity [...]

    Read more

  • Plasma-facing units | China delivers last batch to WEST

    It will be very hot, next summer, on WEST plasma-facing components. Equipped with a full ITER-grade tungsten divertor, the CEA-operated tokamak will enter Phase [...]

    Read more

  • Image of the week | The welding of the feeder stubs

    Operating inside a plastic tent, this welder from MAN Energy Solutions is finalizing the connection between a feeder stub and the cryostat base. Feeder stubs ar [...]

    Read more

  • Fusion world | Technical University of Denmark wins fusion outreach grant

    A consequential grant from the Danish Novo Nordisk Foundation will permit two fusioneers from the Technical University of Denmark (DTU) to broaden their educati [...]

    Read more

  • IAEA Scientific Forum | Urgent need for a clean energy transition

    On 22-23 September the International Atomic Energy Agency held its annual Scientific Forum on the margins of its General Conference. This year's theme was 'N [...]

    Read more

Of Interest

See archived entries

Capturing the hydrogen-species gases

Lynne Degitz, US ITER

Robert Duckworth oversaw the testing of the 2.7-metre-tall ITER cryoviscous compress pump prototype at the Spallation Neutron Source cryogenic test facility. Photo: US ITER/ORNL (Click to view larger version...)
Robert Duckworth oversaw the testing of the 2.7-metre-tall ITER cryoviscous compress pump prototype at the Spallation Neutron Source cryogenic test facility. Photo: US ITER/ORNL
The cryogenic test facility at Oak Ridge National Laboratory's Spallation Neutron Source (SNS) provided a unique environment for testing the performance of a 2.7-metre-tall, tritium-compatible cryoviscous compressor pump prototype designed for the ITER Tokamak.

Initial testing, using deuterium to simulate tritium capture, occurred in late April. So far, the results show that a large portion of deuterium was successfully captured by the pump—a necessary part of the fuel recycling process in the ITER fusion reactor.

"This is the first use of the cryogenic test facility for projects outside SNS," said Sang-Ho Kim, group leader for superconducting LINAC systems in the research accelerator division at SNS. "Our group has been collaborating with the US ITER roughing pumps team for several years, planning for this testing and discussing related technical issues."

The SNS cryogenic test facility was commissioned in 2013 for superconducting radio-frequency cavity testing and can provide refrigeration down to 4.5 Kelvin, or about -273 °C, plus helium liquefaction at a flow rate of 240 litres per hour. These features contribute to an environment with temperatures, pressures and flow rates similar to the requirements of the ITER reactor.

Robert Duckworth, a researcher with the ORNL plasma technologies and applications group within the fusion materials and nuclear systems division, oversaw the cryoviscous compressor (or CVC) pump testing. "The SNS cryo facility worked great," Duckworth said.

A view of the test environment at the Spallation Neutron Source shows a white tank containing helium on the left, the prototype cryoviscous compressor pump in the middle, and the valve box, which monitors the flow rate to the pump, on the right. Photo: US ITER/ORNL (Click to view larger version...)
A view of the test environment at the Spallation Neutron Source shows a white tank containing helium on the left, the prototype cryoviscous compressor pump in the middle, and the valve box, which monitors the flow rate to the pump, on the right. Photo: US ITER/ORNL
"The SNS staff was very engaged and went above and beyond to assure that we had a positive test experience. The CVC performed well in its first full-scale test and was able to freeze deuterium with helium. We learned much that we can take and use for the final installation of the CVC at ITER."

Ultimately, six cryoviscous compressor pumps will be manufactured and installed on the ITER machine. The primary fusion fuels that will be used on ITER are deuterium and tritium. The CVC pumps will take turns evacuating a mix of deuterium, tritium and helium from the ITER Tokamak in order to send the mix on to the tokamak exhaust processing system for fuel recycling. The pumps are "tuned" to freeze out all of the hydrogen-species gases so that fuels can be captured and reused.

"The CVC pump is like a cryogenic filter. Condensation and temperature makes a difference for what material is collected and what passes through the pump," said Mike Hechler, US ITER team leader for the vacuum auxiliary system and roughing pumps. The CVC pump needs to be able to handle the pressure and flow rates of the large ITER machine; these demands are beyond the capabilities of standard industrial pumps. The CVC serves as a link between the vacuum system and the primary cryopumps, which are basic industrial pumps.

Next up for the roughing pump team is to complete testing analysis and determine what design adjustments are necessary to enhance performance of the CVC pump. Another round of testing at the SNS facility is anticipated. US ITER has already fabricated and delivered some roughing pump components to the ITER site, including two screw pumps and one roots pump. In addition, a wide range of vacuum testing equipment and electrical equipment, tokamak cooling water drain tanks, and toroidal field magnet system conductor have been fabricated and delivered by the US for the ITER facility.

Read the complete article on the US ITER website.



return to the latest published articles