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Of Interest

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Fusion world

Public/private consortium is building the DTT tokamak

The Divertor Test Tokamak in Italy is creating a new model for engagement with industry in fusion research. ITER helped to pave the way.

The goal of DTT is to demonstrate innovative solutions for the divertor based either on advanced magnetic configurations or new materials such as liquid metals. Advanced magnetic configurations can spread the heat on a larger surface, so decreasing the local heat flux and help in achieving detached divertor conditions. Liquid metals are not prone to the problems associated with localized melting when solid materials are used. (Click to view larger version...)
The goal of DTT is to demonstrate innovative solutions for the divertor based either on advanced magnetic configurations or new materials such as liquid metals. Advanced magnetic configurations can spread the heat on a larger surface, so decreasing the local heat flux and help in achieving detached divertor conditions. Liquid metals are not prone to the problems associated with localized melting when solid materials are used.
The Divertor Test Tokamak (DTT) will be one of the most technically complex laboratories ever built. Under construction at the Frascati ENEA Research Center, DTT is designed to test divertor concepts that will have the capacity to withstand the thermal exhaust levels of a future demonstration (DEMO) fusion reactor. As the component that extracts helium ash from the tokamak plasma chamber, a divertor in a DEMO-like environment could need to withstand an astonishing 60 MW/m² of heat flux—that's three times what divertor technology can withstand on ITER. Developing a divertor that can survive heat fluxes only found on the surfaces of stars requires the development of a fusion test centre that will push the limits of modern science.

Why, then, does DTT President Francesco Romanelli say that the planned research centre will be just as much of a "sociological laboratory" as a fusion one?

The answer can be found in the annals of the first "fusion roadmap" published in 2012 by the European Fusion Development Agreement (EFDA), the forerunner to the EUROfusion organization. Romanelli, who was at that point running the EFDA, wrote that "defining, designing, building and operating DEMO requires the direct involvement of industry in the fusion programme that in the coming decades will move from being science-driven, laboratory-based towards an industry-driven and technology-driven venture."

At the time it was proposed, Romanelli says, "it was a bold change of direction for the fusion community." Today, the theory is very much in vogue. The IAEA recently announced the creation of the World Fusion Energy Group, an initiative aiming to "bring together not just scientists and engineers from laboratories and experimental centres, but also policy makers, financiers, regulators and private companies" to accelerate the path to commercial fusion energy production. Moreover, in November 2023, the ITER Council called for ITER's engagement with private sector fusion initiatives and, as one illustration, ITER is planning an initial fusion workshop with private sector companies this May. The theory, of course, makes sense. As with anything in fusion, though, such theories need to be tested to be accepted.

As a fusion "sociological laboratory," DTT is doing just that under Romanelli's leadership. The project is set up as a consortium, made up of 11 parties hailing from across the fusion spectrum. Members include ENEA (the institution that manages fusion research within Italy), Italian universities, and Eni—the largest energy company in Italy. The consortium has engaged a number of other private firms such as Ansaldo Nucleare that provides engineering support. Romanelli believes that DTT is "the most effective public/private partnership in the fusion community." Getting there has not necessarily been an easy task. "Academic researchers are looking for the perfect solution," Romanelli says. "Private industry wants to get there as fast as it can, with something that may not be perfect, but that works.

Handling issues like these is the essential role of the consortium. According to Romanelli, DTT acts as a facilitator between the parties to pool their sector-specific knowledge, as well as to allow them to specialize in areas in which they have a wealth of experience. Specifically, Romanelli notes that the combination of ENEA's experience in fusion oversight in Italy, the research capabilities of Italian university laboratories, and the project management expertise of Eni have kept DTT advancing towards its goal. "Put them together, and each of them will have something to learn. In the end, we are 'fusing' them towards a common goal under the umbrella of the consortium."

The involvement of Eni is a particularly compelling example of the contribution DTT is making towards harnessing fusion energy. As one of the world's largest multinational energy firms, Eni's involvement in a project like DTT is a key step in bringing in players with experience in energy distribution to the fusion market. In Romanelli's estimation, as the scientific community draws closer to net energy gain from fusion, it is "only with the spirit of the energy companies" that fusion energy will be harnessed for societal use. Such partnerships between the scientific community around fusion and multinational energy providers may be relied upon to ultimately scale fusion energy in the future.

DTT's partnerships with industry are not limited to the structure of the consortium. As of this writing, approximately one-third of the necessary contracts for DTT have been procured, while the rest of the tenders will be progressively rolled out over the course of construction. In the last year alone, ASG Superconductors Italy—also a supplier to ITER through contracts with the European Domestic Agency Fusion for Energy—has made significant advancements in the preparation of DTT's toroidal field coils, with the first two superconducting winding packs scheduled for completion by the end of this year. In addition, two major tenders for the construction of the DTT buildings and the DTT electrical system are imminent.

Romanelli credits ITER construction as having a direct impact on DTT's ability to procure components with trusted partners in industry, stating that "ITER'sEUR 1.8 billion worth of procurement contracts in Italy alone have developed the industrial capacity to produce the components necessary for DTT." Moreover, according to Romanelli, the manufacturing of superconducting materials for the ITER magnets has boosted the global market for superconducting strands, facilitating procurement at other ventures including DTT.

In complement, there are also areas where ITER is benefitting directly from supply chain advancements attributable to DTT. For example, DTT's gyrotron procurement from Thales AVS France, the testing of which set records for gyrotron performance in September 2023, led to the qualification of Thales through Fusion for Energy for ITER. Beyond procurement, as the DTT and ITER projects will be operating on a generally concurrent timescale, Romanelli says that DTT plans to play a role of support for the ITER project, particularly in materials questions related to ITER's actively cooled full tungsten wall.

Solving the critical question of divertor design is on the "critical path" to getting fusion on the grid as quickly as possible. However, according to Romanelli, "the converging of industry, academia, and public sector research institutions is the pathway to obtaining a fusion power plant sooner than expected." DTT's establishment of best practices for public-private partnerships and engagement with industry may well serve as a role model.

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