Today, many countries are participating in thermonuclear research. The leaders are the European Union, the USA, Russia and Japan, while the programs of China, Brazil, Canada and Korea are growing rapidly. Initially, fusion reactors in the United States and the USSR were associated with the development of nuclear weapons and remained classified until the Atoms for Peace conference held in Geneva in 1958. After the creation of the Soviet tokamak, nuclear fusion research in the 1970s became a "big science". But the cost and complexity of the devices increased to the point where international cooperation was the only way forward.
Fusion reactors in the world
Since the 1970s, commercial use of fusion energy has consistently been pushed back by 40 years. However, much has happened in recent years that could shorten this period.
Several tokamaks have been built, including the European JET, the British MAST and the experimental fusion reactor TFTR in Princeton, USA. The international ITER project is currently under construction in Cadarache, France. It will become the largesttokamak when it starts operating in 2020. In 2030, CFETR will be built in China, which will surpass ITER. Meanwhile, the PRC is conducting research on the EAST experimental superconducting tokamak.
Fusion reactors of another type - stellators - are also popular with researchers. One of the largest, LHD, began work at Japan's National Fusion Institute in 1998. It is used to find the best magnetic plasma confinement configuration. The German Max Planck Institute carried out research on the Wendelstein 7-AS reactor in Garching between 1988 and 2002, and currently on the Wendelstein 7-X, which has been under construction for more than 19 years. Another TJII stellarator is in operation in Madrid, Spain. In the US, the Princeton Plasma Physics Laboratory (PPPL), where the first fusion reactor of this type was built in 1951, h alted construction of the NCSX in 2008 due to cost overruns and lack of funding.
In addition, significant progress has been made in the research of inertial thermonuclear fusion. Construction of the $7 billion National Ignition Facility (NIF) at Livermore National Laboratory (LLNL), funded by the National Nuclear Security Administration, was completed in March 2009. The French Laser Mégajoule (LMJ) began operations in October 2014. Fusion reactors use about 2 million joules of light energy delivered by lasers in a few billionths of a second to a target a few millimeters in size to start a nuclear fusion reaction. The main task of NIF and LMJare studies to support national military nuclear programs.
ITER
In 1985, the Soviet Union proposed to build the next generation tokamak together with Europe, Japan and the US. The work was carried out under the auspices of the IAEA. Between 1988 and 1990, the first designs for the International Thermonuclear Experimental Reactor, ITER, which also means "way" or "journey" in Latin, were created to prove that fusion could produce more energy than it could absorb. Canada and Kazakhstan also participated through the mediation of Euratom and Russia respectively.
After 6 years, the ITER Board approved the first integrated reactor project based on established physics and technology, worth $6 billion. Then the US withdrew from the consortium, which forced them to halve costs and change the project. The result was ITER-FEAT, costing $3 billion but allowing for self-sustaining response and positive power balance.
In 2003, the US rejoined the consortium, and China announced its desire to participate. As a result, in mid-2005, the partners agreed to build ITER in Cadarache in southern France. The EU and France contributed half of the €12.8 billion, while Japan, China, South Korea, the US and Russia contributed 10% each. Japan provided high-tech components, hosted the €1 billion IFMIF facility for materials testing, and had the right to build the next test reactor. The total cost of ITER includes half of the cost of a 10-yearconstruction and half - for 20 years of operation. India became the seventh member of ITER at the end of 2005
Experiments should start in 2018 using hydrogen to avoid magnet activation. D-T plasma usage not expected before 2026
ITER's goal is to generate 500 MW (at least for 400 s) using less than 50 MW of input power without generating electricity.
The 2-gigawatt demo power plant Demo will produce large-scale power generation on an ongoing basis. The concept design for the Demo will be completed by 2017, with construction to begin in 2024. The launch will take place in 2033.
JET
In 1978, the EU (Euratom, Sweden and Switzerland) started a joint European JET project in the UK. JET is the largest operating tokamak in the world today. A similar JT-60 reactor operates at Japan's National Fusion Fusion Institute, but only JET can use deuterium-tritium fuel.
The reactor was launched in 1983, and became the first experiment, which resulted in controlled thermonuclear fusion with a power of up to 16 MW for one second and 5 MW of stable power on deuterium-tritium plasma in November 1991. Many experiments have been carried out in order to study various heating schemes and other techniques.
Further improvements to the JET are to increase its power. The MAST compact reactor is being developed together with JET and is part of the ITER project.
K-STAR
K-STAR is a Korean superconducting tokamak from the National Fusion Research Institute (NFRI) in Daejeon, which produced its first plasma in mid-2008. This is a pilot project of ITER, which is the result of international cooperation. The 1.8 m radius tokamak is the first reactor to use superconducting Nb3Sn magnets, the same ones that are planned to be used in ITER. During the first stage, completed by 2012, K-STAR had to prove the viability of the basic technologies and achieve plasma pulses with a duration of up to 20 s. At the second stage (2013–2017), it is being upgraded to study long pulses up to 300 s in the H mode and transition to the high-performance AT mode. The goal of the third phase (2018-2023) is to achieve high performance and efficiency in the continuous pulse mode. At the 4th stage (2023-2025), DEMO technologies will be tested. The device is not tritium capable and does not use D-T fuel.
K-DEMO
Developed in collaboration with the US Department of Energy's Princeton Plasma Physics Laboratory (PPPL) and South Korea's NFRI, K-DEMO is set to be the next step in commercial reactor development after ITER, and will be the first power plant capable of generating power in electrical network, namely 1 million kW within a few weeks. Its diameter will be 6.65 m and it will have a reproduction zone module being created within the framework of the DEMO project. Korean Ministry of Education, Science and Technologyplans to invest about 1 trillion won ($941 million) in it.
EAST
The Chinese Experimental Advanced Superconducting Tokamak (EAST) at the Chinese Institute of Physics in Hefei created hydrogen plasma at 50 million °C and held it for 102 seconds.
TFTR
In the American laboratory PPPL, the experimental thermonuclear reactor TFTR operated from 1982 to 1997. In December 1993, TFTR became the first magnetic tokamak to carry out extensive experiments with deuterium-tritium plasma. The following year, the reactor produced a then-record 10.7 MW of controllable power, and in 1995, an ionized gas temperature record of 510 million °C was reached. However, the facility did not achieve the goal of break-even fusion energy, but successfully met the hardware design goals, making a significant contribution to the development of ITER.
LHD
The LHD at Japan's National Fusion Fusion Institute in Toki, Gifu Prefecture was the largest stellarator in the world. The fusion reactor was launched in 1998 and has demonstrated plasma confinement qualities comparable to other large facilities. An ion temperature of 13.5 keV (about 160 million °C) and an energy of 1.44 MJ was reached.
Wendelstein 7-X
After a year of testing that began at the end of 2015, the helium temperature briefly reached 1 million °C. In 2016, a fusion reactor with hydrogenplasma, using 2 MW of power, reached a temperature of 80 million ° C within a quarter of a second. W7-X is the largest stellarator in the world and is planned to operate continuously for 30 minutes. The cost of the reactor amounted to 1 billion €.
NIF
The National Ignition Facility (NIF) at Livermore National Laboratory (LLNL) was completed in March 2009. Using its 192 laser beams, NIF is able to concentrate 60 times more energy than any previous laser system.
Cold fusion
In March 1989, two researchers, American Stanley Pons and British Martin Fleischman, announced that they had launched a simple desktop cold fusion reactor operating at room temperature. The process consisted in the electrolysis of heavy water using palladium electrodes, on which deuterium nuclei were concentrated at a high density. The researchers claim that heat was produced that could only be explained in terms of nuclear processes, and there were fusion by-products including helium, tritium and neutrons. However, other experimenters failed to repeat this experience. Most of the scientific community does not believe that cold fusion reactors are real.
Low-energy nuclear reactions
Initiated by claims of "cold fusion", research has continued into the field of low-energy nuclear reactions, with some empirical support, butnot a generally accepted scientific explanation. Apparently, weak nuclear interactions are used to create and capture neutrons (rather than a powerful force, as in nuclear fission or fusion). Experiments include permeation of hydrogen or deuterium through a catalytic bed and reaction with a metal. The researchers report an observed release of energy. The main practical example is the interaction of hydrogen with nickel powder with the release of heat, the amount of which is greater than any chemical reaction can give.
