In the summer of 2020, the leaders of the states involved in the project started the construction of the future reactor’s main element, a tokamak, a plasma confinement and heating system.
The World of Thermonuclear Energy
Thermonuclear reactions can release of tremendous energy, but the plasma where these reactions take place has a temperature of tens and hundreds of millions of degrees, while the most heat-resistant materials can withstand no more than 3-4,000 degrees.
The scientists explained that using thermonuclear energy is possible if the plasma is “torn off” from the reactor walls with strong magnetic fields. The best magnetic trap for thermonuclear plasma, the tokamak, was proposed by Soviet academicians Sakharov and Tamm in the early 1950s and was first created at the Kurchatov Institute.
In a thermonuclear reactor, unlike an atomic one, instead of nuclear fission, nuclear fusion takes place at a plasma density one hundred thousand times less than air density. The scientists stressed that this makes explosions impossible, making the reactor fundamentally safe. The products of such a reactor will be harmless helium and tritium, which is then used to support the reaction.
“The ITER is the gateway to thermonuclear energy which the world should pass through.” These are the words of Academician Evgeny Velikhov, the project’s initiator, Honorary President of the Kurchatov Institute. Born in the mid-1980s, the ITER is aimed at demonstrating the possibility of using fusion energy on an industrial scale.
There are currently seven participants in the project: the EU, India, China, the Republic of Korea, Russia, the US and Japan. The project’s headquarters is in Cadarache, France, close to the construction site.
According to scientists, apart from the fundamental conceptual and engineering contribution to the ITER project, Russian scientists have developed a number of key elements, including the most advanced superconducting cable and the world’s best gyrotrons, devices that heat plasma with ultrahigh-frequency electromagnetic radiation.
The Tritium Challenge
The ITER will use a mixture of hydrogen isotopes, deuterium and tritium, as fuel. Deuterium can be produced relatively easily from water, while tritium will be produced in the fusion reactor. As an experimental installation, the ITER won’t yet produce electricity, but according to scientists, one gramme of fuel from commercial fusion reactors will produce the same amount of energy as 10 to 20 tonnes of hydrocarbons.
One of the risks in the reactor’s operation will be the accumulation of radioactive tritium in the tokamak’s discharge chamber; therefore its amount is limited by safety standards. The chamber’s inner wall, made from tungsten and beryllium, doesn’t accumulate much tritium, however, as the scientists explained, regular remote monitoring of the tritium level is necessary for the reactor’s stable operation.
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