New plasma experiment investigates wall material for ITER
Rijnhuizen creates fusion reactor conditions to design an ideal reactor wall
The new experiment Magnum-PSI of the FOM Institute for Plasma Physics Rijnhuizen produced its first magnetised plasma beam on 4 October. Magnum-PSI is the only facility that can expose materials to plasma (hot, ionised gas) under the same conditions as those in the future fusion reactor ITER. Research in Magnum-PSI will help to design wall materials that are more resilient to the hot, intense plasma in a fusion reactor.
Scientists want to use nuclear fusion, the energy source of the sun, as a clean and sustainable source of energy on earth. During fusion, light atomic nuclei join together to form heavier atomic nuclei, releasing large quantities of energy. The worldwide collaboration on fusion energy is now focused on constructing the advanced reactor ITER in the South of France. From 2019 onwards ITER must demonstrate the technical feasibility of fusion as a source of energy. ITER will have a generating power of 500 megawatt, ten times more than the machine needs itself and just as much as a small power plant.
Interaction between hot plasma and reactor wall
Magnum-PSI has been specially designed to investigate the interaction between the plasma and the reactor wall in ITER in detail. In a fusion reactor the reaction product helium is removed via a special component of the wall, the divertor. At that point the plasma has a temperature of tens of thousands of degrees and the rush of charged particles can damage the reactor wall. The extent to which this happens strongly depends upon the exact conditions present such as the temperature, energy of the particles, plasma density and the magnetic field.
Research questions
Using Magnum-PSI, Rijnhuizen wants to develop strategies to increase the lifespan of the ITER wall. For example, the institute will analyse damage to the wall material and the resultant contamination in the plasma. In another project Rijnhuizen will investigate ways of counteracting the undesired accumulation of the fusion fuel tritium in the wall. Rijnhuizen director Prof. Richard van de Sanden is proud of the new experimental set-up: "Nobody has ever seen what happens to a reactor wall under such intense conditions. Using Magnum-PSI we can investigate that in a laboratory for the first time."
Dr. Pedro Zeijlmans from Emmichoven is in charge of the PSI Operations team that designed and constructed Magnum-PSI and is now making it ready for operation. "The density, intensity, temperature, magnetic field – everything matches the regime in the ITER. We are breaking records here! The conditions that we can achieve here are more than 10 times as intense as in other laboratories."
One of the first plasma bundles in Magnum-PSI, a hydrogen plasma under a magnetic field of 1.4 Teslas. In the background the large roots vacuum pumps can be heard, which keep the ITER machine at a background pressure of less than 1 Pascal. See enclosure of watch http://www.youtube.com/watch?v=ZbbjdEOVb2M