In the upcoming year, two events will signal a significant change from the public to the private sector in the long-running effort to produce plentiful and affordable power from nuclear fusion. The first will be the launch of a machine named SPARC by a private company by the end of 2025. With a potential output of around 140 megawatts (MW), this will be the first fusion reactor—public or private—designed to run at a nearly commercial size. The second will be the failure to open ITER, the multinational fusion collaboration’s flagship project, which was supposed to be completed by 2025. That date was delayed in a hasty statement in July.
Commonwealth Fusion, a Massachusetts Institute of Technology spin-off, is developing SPARC. It’s a tokamak in terms of design. Powerful electromagnets round the machine’s toroidal (doughnut-shaped) reaction vessel, which confines and heats the fuel. That fuel is a plasma of tritium and deuterium, two unusual forms of hydrogen. These conduct a fusion process that releases helium, neutrons, and a significant amount of energy when properly heated and contained.
ITER, which has a 500MW power output target, is also a tokamak. Regretfully, the 35-country partnership constructing it in France will not have it completed by 2025. In actuality, it will not be turned on until 2034, nine years behind schedule. In early 2026, Commonwealth Fusion aims to achieve “q>1,” the point at which a reactor emits more energy than it takes in. According to its revised timeline, ITER won’t get there until 2039.
ITER will most likely come to an end if SPARC is successful and gives the Commonwealth the information it needs to construct a full-scale power plant, which is planned for the early 2030s. Additionally, the Commonwealth is not alone in its attempt to merge with private funds, even if things do not work out as planned.
In contrast to tokamaks, which have up to now been the tried-and-true design for fusion research, several of these companies are investigating more unusual strategies. A Canadian company called General Fusion intends to use liquid-metal chambers to compress and heat a deuterium-tritium plasma. In 2025, a test reactor with a solid compressing metal should be turned on.
Helion, located in Washington state, suggests an alternative fuel consisting of a blend of deuterium and a peculiar helium isotope. In 2025, Polaris, its most recent test-bed, should also be operational. Another Washington-based company, Zap Energy, is bringing back the z-pinch, an outdated method. ENN, based in China’s Hebei province, intends to combine boron and hydrogen. In other words, a lot of other companies are lining up immediately behind Commonwealth Fusion if it doesn’t deliver.
Source: Economist
