The European EUROfusion consortium, following the verification and validation of the scientific data obtained in the deuterium and tritium (DT3) experiments at the end of 2023, announced today that on 3 October 2023 69 megajoules (MJ) of energy were obtained with 0.2 milligrams of fuel during a single pulse over 5 seconds, surpassing the previous world record of 59 MJ from 2022. This is equivalent to the energy released from burning 2 kilograms of coal.
69 megajoules in 5 seconds
The DT3 experimental campaign confirmed the ability to replicate and improve the results of the high-energy fusion experiments already obtained and demonstrated the reliability of JET’s operational methodologies, essential for the success of the international ITER experimental reactor currently under construction. More than 300 scientists from all European fusion laboratories participated in the experiments, carried out on the European facility located at the UKAEA (United Kingdom), with a strong Italian participation in key scientific and organizational leadership roles.
The Joint European Torus (JET) thus concluded its experimental life. It was the largest European fusion plant, the only one capable of operating with a fuel mixture composed of deuterium and tritium, the same high-performance mixture that will be used in future fusion power plants that will try to reproduce the same on Earth mechanism that ‘turns on’ the stars to obtain renewable and inexhaustible energy.
But how does nuclear fusion happen?
To date, to reproduce the mechanism that lights up the stars, scientific research uses a machine called Tokamak, with a toroidal shape, characterized by a hollow casing, with a special ‘reaction chamber’ inside covered by a mantle made up of containers of lithium. The fusion reaction is reproduced inside the Tokamak using the lithium present in the coating, deuterium, a form of hydrogen which sea water is rich in (30 g/m3) and tritium, generated directly inside the Tokamak, in a closed loop. Deuterium and tritium are introduced into the reaction chamber and brought to temperatures of 200 million degrees, more than ten times the interior of the Sun, transforming into a compound of separate charged particles, nuclei and electrons, or plasma.
To achieve this result, highly sophisticated systems are used, based on the use of electromagnetic waves or beams of neutral particles. To prevent the plasma particles from moving disorderly, hitting and damaging the walls, losing precious energy and, consequently , by inhibiting the fusion reaction, large magnets are placed around the reaction chamber inside the Tokamak which have the task of producing magnetic fields capable of ‘confining’ the plasma”.
The transition from the fusion reaction to the production of electrical energy occurs “through the neutrons generated by the union between deuterium and tritium: the energy of the neutrons is deposited inside the shell of the reaction chamber where it is transformed into steam which powers a gigantic turbine to produce electricity. The helium that remains in the various steps of the process is disposed of without problems. The characteristic of fusion is the ability to self-sustain thanks to the energy produced in the fusion itself; however, the process must be constantly fueled by injecting gas of deuterium and tritium into the reaction chamber and removing the helium produced.In fact, if the injection stops, the reaction shuts down immediately.
“JET has operated as close to power station conditions as possible with today’s facilities, and its legacy will be pervasive in all future power stations. It has a vital role in bringing us closer to a safe and sustainable future,” explains Sir Ian Chapman, CEO of the UKAEA.
The one recorded by the Jet reactor was “a swan song”, the last great success of the experimental reactor which went into retirement at the end of December 2023, after 40 years of activity. But for the new nuclear fusion program the British government has committed 650 million pounds to invest in research and new infrastructure.