While the International Thermonuclear Experimental Reactor (ITER) achieved a major machine assembly milestone in May 2022 with the first sub-section of the ITER plasma chamber being lifted out of tooling and lowered into the machine well, the ITER organisation is currently having to revise the timelines for the world’s largest nuclear fusion project owing to the COVID-19 pandemic.
The ITER machine, the assembly of which began in July 2020 in France, is a first-of-its-kind project designed to replicate the fusion power of the sun to enable generation of clean unlimited energy. When light atomic nuclei fuse together to form heavier ones, a large amount of energy is released, which fusion reaction is to be housed in the ITER plasma chamber.
ITER expects to generate its first ultra-hot plasma in late 2025, but the pandemic is going to result in a postponement of this target date. According to an ITER spokesperson, given the scale of the project and its unique technical specifications, delays to the schedule are widely expected.
“Multiple factories making ITER components shut down – some for months – and when they restarted in some instances, it was not with the same workforce or expertise”, the spokesperson said.
ITER is a 35-nation partnership composed of the European Union, the UK, Switzerland, China, India, Japan, South Korea, Russia and the US. Each partner contributes in-kind hardware to support their share of project construction while sharing all of the science and technology.The world’s largest science project is intended to demonstrate that fusion power can be generated on a commercial scale.
“ITER’s First Plasma is scheduled for December 2025. This important milestone will mark the end of the construction phase and the transition to operation. The date of this milestone is subject to change. Due to the impact Covid-19 has had on ITER manufacturing, the project is in the process of re-evaluating some technical milestones. Changes to ITER’s Baseline schedule can only be made by the ITER Council”, an ITER notification said.
“Project re-baselining is underway, aiming at approval of an Updated Baseline in 2023, taking into account the effects of technical challenges and the pandemic”, an ITER statement said last month.
ITER’s plasma chamber, or vacuum vessel, will be formed from nine wedge-shaped steel sectors that measure over 14 metres in height and weigh 440 tonnes. The section of the ITER machine that was lowered into the machine well in May this year represents one-ninth of the toroidal plasma chamber.
The “tokamak” (derived from the Russian words for “toroidal magnetic confinement”) machine, which will produce thermonuclear fusion power, relies on magnets to propel and shape its plasma stream. It initiates plasma current, as well as drives and shapes the plasma during operation.
“ITER’s tallest electromagnet—the 18-metre-tall central solenoid—will be the last major component to be installed in the machine before the cryostat is closed up. Installation activities will begin in late 2023 (fourth quarter 2023)”, ITER said, adding that “the date of this milestone is subject to change due to the impact Covid-19 has had on ITER manufacturing”.
World Nuclear News (WNN) reports that a proposed new timetable has been presented last month to the ITER Council, which has, however, launched the search for a new Director General (DG) of ITER, following the death of Bernard Bigot in May. According to WNN, a new project schedule is unlikely to be unveiled prior to the second quarter of 2023.
The French nuclear regulator, Autorité de Sûreté Nucléaire (ASN), which supervises the ITER project said in a statement: “The year 2021 was marked in particular by the preparation of the first sector of the vacuum chamber, with the installation of its equipment and thermal protection in the assembly hall, in order to be able to transfer it to the shaft of the Tokamak building at a later date. A second sector has arrived on site and must also be equipped.”
“Work on the site and the manufacture of equipment are continuing. The revision of the schedule, integrating the assessment of the impact of the COVID-19 pandemic, is still awaited”, it added.
The ITER vacuum vessel, with an interior volume of 1,400 cubic metres, is unique — it can contain 840 cubic metres of plasma, which is ten times larger than that of the largest tokamak currently operating in the world. Once assembled, the ITER vacuum vessel will have an outer diameter of 19.4 metres, a height of 11.4 metres, and weigh approximately 5,200 tonnes. With the subsequent installation of in-vessel components such as the blanket and the divertor, the vacuum vessel will weigh 8,500 tonnes.
ITER’s realisation of a self-heating plasma is expected to generate 10 times more heat than is put in. Fusion provides clean, reliable energy without carbon emissions, with minute amounts of fuel and no physical possibility of an accident with meltdown. The fuel for fusion is found in seawater and lithium, while it is abundant enough to supply the world for millions of years. A football-sized amount of this fuel is equivalent to around 10,000 tons of coal.
