Nuclear fusion has been under research for decades. The majority of research worldwide focusses on so-called deuterium-tritium fusion (D-T fusion) based on magnetic confinement fusion. In other words, nuclear fusion is to be achieved by means of a magnetic field.

There are a handful of experimental facilities around the world that endeavour to generate energy by means of nuclear fusion. To date, however, not a single experimental facility exists anywhere in the world that uses nuclear fusion to produce more energy than it needs to operate, or that might even be able to generate electricity.
‘ITER’ is the most advanced prototype of a fusion reactor under construction worldwide: ‘ITER’ is intended to prove the technical feasibility of a nuclear fusion power plant, without any plans to generate electricity. A great deal of research and development is still needed before the ‘ITER’ fusion reactor prototype can become an electricity-generating experimental reactor.

Recently published advances in the field of nuclear fusion, for example in the USA, relate to basic research findings regarding nuclear fusion based on laser fusion. This involves the use of high-energy lasers rather than a magnetic field to achieve fusion. It is currently impossible to predict whether or when the first commercial fusion power plant for generating electricity might be built.

The following are examples of nuclear fusion research projects and their envisaged time horizons:

• The ‘ITER’ experimental reactor has been under construction by an international consortium (China, EU, India, Japan, Korea, Russia and USA) in Cadarache, France, since 2010. The experimental reactor is intended to prove the basic feasibility of a fusion power plant based on magnetic confinement fusion. This means that nuclear fusion is to be achieved technically by means of a magnetic field. The aim is to generate 500 megawatts of fusion power for longer than 300 seconds (5 minutes). The original plan was to achieve this goal by 2035-2040, but the project is facing considerable delays and cost increases. A new timetable is to be announced in 2024. 'ITER' is purely about fusion power and not about generating electricity.
• In addition to the ‘ITER’ test reactor, the EUROfusion consortium is pushing ahead with the development of the ‘DEMO’ (magnetic confinement fusion) fusion reactor prototype. Such a prototype is planned for Europe from 2050, and is expected to produce around 500 megawatts of electricity per year (in comparison: nuclear power plants approx. 1400 MW). The EUROfusion consortium was founded in 2014. It is made up of state research institutions from EU member states (including several German ones) and Switzerland. With the ‘DEMO’ project, EUROfusion is researching a possible commercial utilisation of nuclear fusion.
• The Wendelstein 7-X, the world's largest experimental facility of the stellarator type, is operated in Greifswald. Its task is to investigate the suitability of this special type of construction for a fusion power plant. The main assembly of Wendelstein 7-X was completed in 2014 and the first plasma was generated on 10 December 2015. Wendelstein 7-X is purely an experimental facility for researching nuclear fusion. The facility is still a long way from being a prototype power plant.
• Numerous private companies around the world are currently pursuing the topic of nuclear fusion. Many of them intend to build experimental reactors by 2030-2035. Such claims are mostly mere declarations of intent and cannot be independently verified.

Information:

• The IAEA has published the ‘IAEA World Fusion Outlook’.
• In Germany, the promotion of nuclear fusion falls within the remit of the Ministry of Education and Research (BMBF). The BMBF published a ‘Position Paper on Fusion Research’ on 23 June 2023 (in German).
  

What are the characteristics of nuclear fusion?

• A fusion process would generate significantly lower activity inventories than nuclear fission (nuclear power plant). According to the classification of the International Atomic Energy Agency (IAEA), no high- level radioactive waste would be produced.
• The radioactive fuel tritium (half-life 12.3 years) would become embedded in materials. Furthermore, the neutron radiation that occurs during nuclear fusion would activate components of the reactor (material-independent half-lives). This would result in the continued production of radionuclides, resulting in low- and intermediate- level radioactive residues, initially in the form of components of the fusion reactor. In the case of nuclear fusion, large quantities of low- and intermediate- level radioactive residues are to be expected. They would have to be further processed, stored temporarily and, in some cases, permanently disposed of safely.
• The fusion plasma will self-extinguish as soon as the energy supply is interrupted and, in contrast to a nuclear power plant, there is no significant production of residual heat. A catastrophic reactor accident with the same consequences as with a nuclear power plant is, therefore, practically impossible.
• A major radiological risk of nuclear fusion would be the use of the radioactive fuel tritium (half-life 12.3 years). And, as radioactive substances would be produced during nuclear fusion, there would be a basic radiological risk during the operation, maintenance and dismantling of plants, as well as in the event of possible incidents and accidents.
• Nuclear fusion is expected to consume a small three-digit kilogramme quantity of each fuel (deuterium and tritium) per year and gigawatt of electrical power plant output; however, this is only an assumption so far. (Source: ‘DEMO’ project, Gianfranco Federici from EUROfusion; FEC 2023; 16-21 October 2023, London, UK). By comparison, nuclear power plants require around 170 tonnes of uranium per year (= around 80,000 tonnes of rock).
• Nuclear fusion would reduce dependence on raw materials, as tritium fuel could be produced from small quantities of lithium in the fusion power plant itself. However, many questions remain unanswered regarding the breeding of tritium.