Europe to test steel for future fusion reactors

ITER will be the first fusion device to test tritium breeding—an essential technology for the fusion reactors of the future. While the fusion fuel deuterium can be distilled from all forms of water, tritium occurs only in trace quantities in nature.

Scientists know that tritium can be produced during the fusion reaction through contact with lithium: tritium is produced, or "bred," when neutrons escaping the plasma interact with lithium contained in the blanket wall of the tokamak.

Six tritium breeding concepts will be tested during the deuterium-tritium phase of ITER operation. Of these, the European Domestic Agency is responsible for two.

Europe is considering the use of EUROFER97 as the candidate steel material for its tritium breeding modules. Among its many advantages, this steel responds well to neutron activation and offers good resistance to neutron irradiation. It is compatible with liquid metal and ceramic breeders and its properties seem to respond well at high temperatures.

Through a contract signed with Studsvik (Sweden), a series of tests will be performed to learn more about the physical and mechanical properties of EUROFER97. Studsvik and NRG, its subcontractor, were awarded a contract in October by Europe for a detailed technical analysis. The tests are expected to last five years.

NRG will irradiate specimens in the High Flux Reactor in Petten (The Netherlands) under controlled conditions similar to those in ITER. After irradiation, the material samples will be transported to Studsvik for post-irradiation examination and characterization. The tests and examination will quantify the level at which neutron irradiation affects fatigue properties or fracture toughness, causes deformation, and/or influences the mechanical properties of this potential structural material for the blankets of future fusion reactors.