On Tuesday, the people running the experimental fusion reactor ITER announced that a combination of delays and changed priorities means its first-of-its-kind hardware won’t see plasma until 2036, with full-energy deuterium-tritium fusion pushed back. until 2039. This represents a four-year delay compared to the previous plan. While the former is also delayed, this is partly due to a change in priorities.
COVID and construction delays
ITER is an attempt to build a fusion reactor capable of sustaining a plasma that will allow it to operate far beyond the break-even point, where the energy released by fusion reactions far exceeds the energy needed to create the conditions that allow those reactions to occur. The goal is to achieve this milestone by extending a well-understood design called a tokamak.
But the issue has been plagued by delays and cost overruns almost from the start. In the early stages, many of these came from changes in designs that required a better and better understanding of plasmas maintained at extreme pressures and temperatures through better modeling capabilities and a better understanding of plasma behavior in smaller reactions.
The latest delays have more prosaic reasons. One of them is a product of an international nature of cooperation, where individual components are built by various partner organizations before assembly at the reactor site in France. Unsurprisingly, the pandemic severely disrupted the production of many of these components, and the structure of the project meant that alternative suppliers could not be used (assuming there were alternative suppliers of the unique hardware in the first place).
The second problem concerns the location of the reactor in France. The nuclear safety regulator there was concerned about the assembly of some components and stopped construction of the reactor.
High energy from the start
During the reassessment of the schedule that these delays would require, the organization that manages ITER has reassessed some of its priorities. In the previous plan, the priority would have been to get the plasma into the machine, as the relatively low-energy hydrogen plasma was put into the machine before all the final hardware was completed. This would require a longer shutdown after the initial experiments before the reactor could be used at progressively higher energies, using stronger deuterium and deuterium/tritium plasmas.
In the previous plan, low-energy plasma containing only hydrogen would have begun testing in 2025, a target date that made the delay completely unrealistic. Instead, they will now occur in 2034. However, rather than a set of short demonstrations, these experiments will continue for more than two years and reach much higher energies. So while the plasma in the machine will be delayed by almost a decade, the system’s magnets will reach power only three years later than expected under the previous plan.
Full-power operation using a deuterium/tritium fuel mixture will be delayed by four years. Even if this new plan is followed, it won’t be until 2039.
So we are looking at 15 years even if there is no further delay. However, the potential for said delays is likely to have increased as the announcement suggests that ITER will switch to a different material (from beryllium to tungsten) for the construction of the inner wall that faces the plasma. This will become more relevant as many other projects, including commercial fusion startups, plan to use tungsten. However, it may still add a new set of technical and production delays.
But the risk for ITER is that all these delays will cause some of the nations that support the project to back out. Or, if some of the commercial fusion startups they’ve launched have, they’re creating the risk that by the time ITER is ready to go, fusion will already be here.