The International Thermonuclear Experimental Reactor (ITER) is the effort of 35 countries to produce electricity from nuclear fusion, announcedto postpone the start of operation for at least eight years.
A tokamak is a generally torus-shaped device capable of storing gases transformed into plasma, exposed to extreme heat and pressure, in the magnetic field created by electromagnets placed in a circle. The hot plasma is kept away from the chamber walls by powerful magnets, and the heat is used to boil water into steam, which drives turbines to generate electricity. ITER has built the world’s largest tokamak and hopes to create a deuterium-tritium plasma in which fusion conditions are maintained mainly by internal fusion heating, without the need for constant input of energy. The project aims to produce 500 MW of fusion power from 50 MW of input energy, as a demonstration that points the way for commercial exploitation.
Pietro Barabaschi, Director General of ITER, outlined the project new baseline, which replaces the one used since 2016. This older document predicted the “first plasma” by 2025 – but only as a “short, low-energy machine experiment with relatively minimal scientific value”. The planned series of experiments would have continued until 2033. The organization has been aware since 2020 that the 2025 deadline cannot be met, so these changes are not unexpected. COVID-19 has complicated the already difficult effort to build the tokamak, which has been plagued by quality problems and overly optimistic assumptions about the production of parts. The operation of ITER requires 6,000 tons of magnets capable of storing 41 gigajoules of energy. This can’t be easy to build!
“We could have kept the 2016 schedule, but that would have been illogical – based on the availability of additional key components to build a more complete machine,” admitted Barabaschi. The new baseline prioritizes the start of exploration operations, which are now expected to begin in 2033. Barabaschi explained that the delay gives ITER the opportunity to carry out further tests on some of the tokamak elements, meaning a “more complete machine” will be available by 2033. ITER wants the deuterium-tritium operational phase to begin in 2039 – four years later than originally planned.
One of the big changes compared to the basic design is that tungsten is used instead of beryllium for the front wall of the tokamak – the part facing the plasma. ITER experts decided that tungsten was “more relevant for future use and possible commercial fusion equipment”. An additional 5 billion euros will be needed to implement the plan. ITER members are considering this requirement. ITER’s statement announcing the new baseline notes that “costs have traditionally been difficult to accurately estimate, as most of the financial contributions are provided by ITER members in kind, in the form of components, the actual costs of most of which are not required to be published by the governments of the member countries”. So let’s take the 5 billion euro number with a big pinch of reservation.
Fusion experiments have shown that the technology is promising as a clean energy source, which is why governments are pouring money into it. So far, however, no experiment has come close to ITER’s intended performance – or even reliable operation.
Source: sg.hu
