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ITER (originally the International Thermonuclear Experimental Reactor[1]) is an international nuclear fusion research and engineering megaproject, which will be the world's largest magnetic confinement plasma physics experiment. It is an experimental tokamak nuclear fusion reactor that is being built next to the Cadarache facility in Saint-Paul-lès-Durance, in Provence, southern France.[2]
The ITER thermonuclear fusion reactor has been designed to produce a fusion plasma of 500 megawatts (MW) for around twenty minutes while 50 megawatts of thermal power are injected into the tokamak, resulting in a ten-fold gain of plasma heating power.[3] Thereby the machine aims to demonstrate the principle of producing more thermal power from the fusion process than is used to heat the plasma, something that has not yet been achieved in any fusion reactor. The total electricity consumed by the reactor and facilities will range from 110 MW up to 620 MW peak for 30-second periods during plasma operation.[4] Thermal-to-electric conversion is not included in the design because ITER will not produce sufficient power for net electrical production. The emitted heat from the fusion reaction will be vented to the atmosphere.[5][6]
The project is funded and run by seven member entities—the European Union, India, Japan, China, Russia, South Korea and the United States. The EU, as host party for the ITER complex, is contributing about 45 percent of the cost, with the other six parties contributing approximately 9 percent each.[7][8][9] In 2016 the ITER organization signed a technical cooperation agreement with the national nuclear fusion agency of Australia, granting this country access to research results of ITER in exchange for construction of selected parts of the ITER machine.[10]
Construction of the ITER Tokamak complex started in 2013[11] and the building costs were over US$14 billion by June 2015.[12] The construction of the facility is expected to be completed in 2025 when commissioning of the reactor can commence. Initial plasma experiments are scheduled to begin in 2025, with full deuterium–tritium fusion experiments starting in 2035.[13][14] If ITER becomes operational, it will become the largest magnetic confinement plasma physics experiment in use with a plasma volume of 840 cubic meters,[15] surpassing the Joint European Torus by almost a factor of 10.
The goal of ITER is to demonstrate the scientific and technological feasibility of fusion energy for peaceful use.[16] It is the largest of more than 100 fusion reactors built since the 1950s.[16] ITER's planned successor, DEMO, is expected to be the first fusion reactor to produce electricity in an experimental environment. DEMO's anticipated success is expected to lead to full-scale electricity-producing fusion power stations and future commercial reactors.[17]
Contents
1 Background
2 Organization history
3 Objectives
4 Timeline and status
5 Reactor overview
6 Technical design
6.1 Vacuum vessel
6.2 Breeder blanket
6.3 Magnet system
6.4 Additional heating
6.5 Cryostat
6.6 Cooling systems
7 Location
8 Participants
9 Funding
10 Criticism
10.1 Responses to criticism
11 Similar projects
12 See also
13 References
14 External links
Background
ITER will produce energy by fusing deuterium and tritium to helium.
Fusion power has the potential to provide sufficient energy to satisfy mounting demand, and to do so sustainably, with a relatively small impact on the environment.
Nuclear fusion has many potential attractions. Firstly, its hydrogen isotope fuels are relatively abundant – one of the necessary isotopes, deuterium, can be extracted from seawater, while the other fuel, tritium, would be bred from a lithium blanket using neutrons produced in the fusion reaction itself.[18] Furthermore, a fusion reactor would produce virtually no CO2 or atmospheric pollutants, and its radioactive waste products would mostly be very short-lived compared to those produced by conventional nuclear reactors (fission reactors).
On 21 November 2006, the seven participants formally agreed to fund the creation of a nuclear fusion reactor.[19] The program is anticipated to last for 30 years – 10 for construction, and 20 of operation. ITER was originally expected to cost approximately €5 billion, but the rising price of raw materials and changes to the initial design have seen that amount almost triple to €13 billion.[12] The reactor is expected to take 10 years to build with completion originally scheduled for 2019, but construction has continued into 2020.[20] Site preparation has begun in Cadarache, France, and procurement of large components has started.[21]
When supplied with 300 MW of electrical power, ITER is expected to produce the equivalent of 500 MW of thermal power sustained for up to 1,000 seconds.[22] This compares to JET's consumption of 700 MW of electrical power and peak thermal output of 16 MW for less than a second) by the fusion of about 0.5 g of deuterium/tritium mixture in its approximately 840 m3 reactor chamber. The heat produced in ITER will not be used to generate any electricity because after accounting for losses and the 300 MW minimum power input, the output will be equivalent to a zero (net) power reactor.[5]
Organization history
Ronald Reagan and Mikhail Gorbachev at the Geneva Summit in 1985
ITER began in 1985 as a Reagan–Gorbachev[23][24] initiative[24][25] with the equal participation of the Soviet Union, the European Atomic Energy Community, the United States, and Japan through the 1988–1998 initial design phases. Preparations for the first Gorbachev-Reagan Summit showed that there were no tangible agreements in the works for the summit.
One energy research project, however, was being considered quietly by two physicists, Alvin Trivelpiece and Evgeny Velikhov. The project involved collaboration on the next phase of magnetic fusion research — the construction of a demonstration model. At the time, magnetic fusion research was ongoing in Japan, Europe, the Soviet Union and the US. Velikhov and Trivelpiece believed that taking the next step in fusion research would be beyond the budget of any of the key nations and that collaboration would be useful internationally.
A major bureaucratic fight erupted in the US government over the project. One argument against collaboration was that the Soviets would use it to steal US technology and know-how. A second was symbolic — the Soviet physicist Andrei Sakharov was in internal exile and the US was pushing the Soviet Union on its human rights record. The United States National Security Council convened a meeting under the direction of William Flynn Martin that resulted in a consensus that the US should go forward with the project.
Martin and Velikhov concluded the agreement that was agreed at the summit and announced in the last paragraph of this historic summit meeting, "... The two leaders emphasized the potential importance of the work aimed at utilizing controlled thermonuclear fusion for peaceful purposes and, in this connection, advocated the widest practicable development of international cooperation in obtaining this source of energy, which is essentially inexhaustible, for the benefit for all mankind."[26]
Conceptual and engineering design phases carried out under the auspices of the IAEA led to an acceptable, detailed design in 2001, underpinned by US$650 million worth of research and development by the "ITER Parties" to establish its practical feasibility.[citation needed] These parties, namely EU, Japan, Russian Federation (replacing the Soviet Union), and United States (which opted out of the project in 1999 and returned in 2003), were joined in negotiations by China, South Korea, and Canada (who then terminated its participation at the end of 2003). India officially became part of ITER in December 2005.
On 28 June 2005, it was officially announced that ITER would be built in the European Union in Southern France. The negotiations that led to the decision ended in a compromise between the EU and Japan, in that Japan was promised 20% of the research staff on the French location of ITER, as well as the head of the administrative body of ITER. In addition, another research facility for the project will be built in Japan, and the European Union has agreed to contribute about 50% of the costs of this institution.[27]
On 21 November 2006, an international consortium signed a formal agreement to build the reactor.[28] On 24 September 2007, the People's Republic of China became the seventh party to deposit the ITER Agreement to the IAEA. Finally, on 24 October 2007, the ITER Agreement entered into force and the ITER Organization legally came into existence.
Objectives
ITER's mission is to demonstrate the feasibility of fusion power, and prove that it can work without negative impact.[29] Specifically, the project aims to:
Momentarily produce a fusion plasma with thermal power ten times greater than the injected thermal power (a Q value of 10).
Produce a steady-state plasma with a Q value greater than 5. (Q = 1 is scientific breakeven.)
Maintain a fusion pulse for up to 8 minutes.
Develop technologies and processes needed for a fusion power station — including superconducting magnets and remote handling (maintenance by robot).
Verify tritium breeding concepts.
Refine neutron shield/heat conversion technology (most of the energy in the D+T fusion reaction is released in the form of fast neutrons).
Timeline and status
Aerial view of the ITER site in 2018
ITER construction status in 2018
In 1978, the European Commission, Japan, United States, and USSR joined in the International Tokamak Reactor (INTOR) Workshop, under the auspices of the International Atomic Energy Agency (IAEA), to assess the readiness of magnetic fusion to move forward to the experimental power reactor (EPR) stage, to identify the additional R&D that must be undertaken, and to define the characteristics of such an EPR by means of a conceptual design. Hundreds of fusion scientists and engineers in each participating country took part in a detailed assessment of the then present status of the tokamak confinement concept vis-a-vis the requirements of an EPR, identified the required R&D by early 1980, and produced a conceptual design by mid-1981.
In 1985, at the Geneva summit meeting in 1985, Mikhail Gorbachev suggested to Ronald Reagan that the two countries jointly undertake the construction of a tokamak EPR as proposed by the INTOR Workshop. The ITER project was initiated in 1988.[30][31] |