ITER breeding blanket and tritium plant plans advance

ITER has announced progress on its tritium breeding and processing efforts, including the success of a summit bringing together the teams that are developing its tritium plant and the selection of four breeding blanket systems that will be tested at ITER.

Tritium plant summit: Last week, 70 participants from the ITER Organization and its partners gathered for a summit to discuss ITER's tritium plant, which will receive, store, and process tritium; separate it from other gases; and recycle it through the fusion fuel cycle.

"Tritium handling, processing, recovery, and recycling are some of the big technical issues for fusion development, and this summit is an opportunity to bring everyone across the project together to make progress on these topics," said Ian Bonnett, tritium plant project leader. "This year's event was particularly important because we have reached a level of maturity at which contracts are being placed. Suppliers attended the summit to share experiences and discuss common challenges, allowing us to break new ground and solve problems together."

According to ITER, the tritium plant's systems all have reached final design status. Fabrication and installation of the first components, such as water tanks and piping networks, is continuing.

The plant has six subsystems that process tokamak exhaust through multiple stages, including isotope separation, atmospheric detritiation, and water detritiation.

During the summit, ITER Domestic Agencies reported progress on major procurement activities, while engineering partners presented work on design maturation, prototyping, and qualification of key technologies.

Bonnett said he was encouraged by the progress made at the summit. "I am confident that, by continuing to work together as one team, we can successfully meet these challenges and deliver the tritium plant safely and efficiently."

Selected concepts: ITER announced that four breeding blanket concepts have passed preliminary design reviews and will be tested and validated through its Test Blanket Module (TBM) program during ITER's first deuterium-tritium operation phase.

The concepts include water-cooled lead-lithium technology (developed by Europe), water-cooled ceramic breeder technology (developed by Japan), helium-cooled ceramic breeder technology (developed by China), and helium-cooled ceramic pebble technology (developed jointly by Korea and Europe).

The TBM program was established in 2008 to carry out one of ITER's core missions: testing concepts for achieving self-sufficiency in tritium supply for future fusion power plants.

According to the ITER press release, scientists and engineers conducted extensive reviews of the engineering assessments for each blanket system configuration, ensuring the designs demonstrated preliminary readiness for integration, safety, and operation on ITER as well as suitability for tritium breeding in next-phase DEMO devices (DEMO is a proposed demonstration fusion power plant that is intended to follow ITER).

Each blanket technology is supported by detailed engineering analyses and technical documents including models; electromagnetic analyses; thermal-hydraulic and mechanical verifications; nuclear and safety assessments; manufacturing feasibility plans; and finally plans for installation, commissioning, operations, maintenance, and decommissioning.

"The awesome challenge of the ITER members is to develop the test blanket system technologies that can be tested in ITER then incorporated as breeding blanket solution[s] for the DEMO reactor, or other future fusion reactors after ITER," said Rossella Rotella, project leader of the tritium blanket breeding section. "Passing the preliminary design reviews represents a breakthrough landmark for the TBM program and for fusion technology development. It also testifies to the outstanding multidisciplinary and international cooperation among the ITER members and the ITER Organization."

Each test blanket system will be independently integrated and operated on ITER. Each will have a module near the plasma containing a tritium breeder and neutron multiplier together with its primary coolant, which is designed for heat removal at the level needed in a power production facility.

The selected blanket technologies are now considered ready for the final engineering phase.

Mu-young Ahn, who heads the development of TBM and breeding blanket technologies at the Korea Institute of Fusion Energy, noted that the helium-cooled ceramic pebble system that was selected is closely linked to the development of the breeding blankets for Korea's Compact Pilot Device, and the execution of the system at ITER will provide a foundation for that work.

"This return on experience from ITER will serve as a practical bridge to our new device while helping us address the remaining challenges in tritium management, materials, and integrated blanket engineering," said Ahn.