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ITER (originally the International Thermonuclear Experimental Reactor), pronounced eat-er, is an international research and engineering project which is currently building the world's largest and most advanced experimental tokamak nuclear fusion reactor and will be constructed in Europe, at Cadarache in the south of France. The ITER tokamak aims to make the long awaited transition from today's studies of plasma physics to full scale electricity-producing fusion power plants. The project's members are the European Union, India, Japan, People's Republic of China, Russia, South Korea and the United States. The EU as host party for ITER will contribute 45% of the cost, with the other parties contributing 9% each. The fusion reactor itself has been designed to produce 500 MW of output power for 50 MW of input power, or ten times the amount of energy put in. The machine is expected to demonstrate the principle of getting more energy out of the fusion process than is used to initiate it, something that has not been achieved with previous fusion reactors. Construction of the facility began in 2007 and first plasma is expected in 2019. When ITER becomes operational it will surpass the Joint European Torus which is the current largest magnetic confinement plasma physics experiment in use. The first commercial demonstration fusion power plant named DEMO is proposed to follow on the research of ITER to bring fusion energy to the commercial markets.
Fusion has many potential attractions:
On November 21, 2006, the seven participants formally agreed to fund the creation of a nuclear fusion reactor. The program is anticipated to last for 30 years – 10 for construction, and 20 of operation. ITER was originally expected to cost approximately €5billion, but the rising price of raw materials and changes to the initial design have seen that amount more than triple to €16billion. The reactor is expected to take 10 years to build with completion scheduled for 2019. Site preparation has begun in Cadarache, France and procurement of large components has started.
ITER is designed to produce approximately 500 MW of fusion power sustained for up to 1,000 seconds (compared to JET's peak 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. Although ITER is expected to produce (in the form of heat) 10 times more energy than the amount consumed to heat up the plasma to fusion temperatures, the generated heat will not be used to generate any electricity.
ITER was originally an acronym for International Thermonuclear Experimental Reactor, but that title was dropped due to the negative popular connotation of "thermonuclear", especially when in conjunction with "experimental". "Iter" also means "journey", "direction" or "way" in Latin, reflecting ITER's potential role in harnessing nuclear fusion as a peaceful power source.
On 21 November 2006, an international consortium signed a formal agreement to build the reactor.
On 24 September 2007, the People's Republic of China became the seventh party who had deposited the ITER Agreement to the IAEA.
On 24 October 2007, the ITER Agreement entered into force and the ITER Organization legally came into existence.
The process of selecting a location for ITER was long and drawn out. The most likely sites were Cadarache in Provence-Alpes-Côte-d'Azur, France and Rokkasho, Aomori, Japan. Additionally, Canada announced a bid for the site in Clarington in May 2001, but withdrew from the race in 2003. Spain also offered a site at Vandellòs on 17 April 2002, but the EU decided to concentrate its support solely behind the French site in late November 2003. From this point on, the choice was between France and Japan.
On 3 May 2005, the EU and Japan agreed to a process which would settle their dispute by July.
At the final meeting in Moscow on 28 June 2005, the participating parties agreed on the site in Cadarache in Provence-Alpes-Côte-d'Azur, France.
Construction of the ITER complex began in 2007, while assembly of the tokamak itself is scheduled to begin in the year 2015.
ITER's work is supervised by ITER Council, which has the authority to appoint senior staff, amend regulations, decide on budgeting issues, and allow additional states or organizations to participate in ITER. ITER Council's chairman is Evgeny Velikhov, initiator of ITER project.
Although Japan's financial contribution as a non-hosting member is 1/11th of the total, the EU agreed to grant it a special status so that Japan will provide for 2/11th of the research staff at Cadarache and be awarded 2/11th of the construction contracts, while the European Union's staff and construction components contributions will be cut from 5/11th to 4/11th.
It was reported in December 2010 that the European Parliament has refused to approve a plan by Member states to reallocate 1.4bn euros from the budget to cover a shortfall in ITER building costs in 2012-13. Closure of the 2010 budget means this financing plan will have to be revised and the European Commission (EC) will put forward an ITER budgetary resolution proposal next year.
A technical concern is that the 14 MeV neutrons produced by the fusion reactions will damage the materials from which the reactor is built. Research is in progress to determine how and/or if reactor walls can be designed to last long enough to make a commercial power plant economically viable in the presence of the intense neutron bombardment. The damage is primarily caused by high energy neutrons knocking atoms out of their normal position in the crystal lattice. A related problem for a future commercial fusion power plant is that the neutron bombardment will induce radioactivity in the reactor itself. Maintaining and decommissioning a commercial reactor may thus be difficult and expensive. Another problem is that superconducting magnets are damaged by neutron fluxes. A new special research facility is planned for this activity, IFMIF.
A number of fusion researchers working on non-tokamak systems, such as Robert Bussard and Eric Lerner, have been critical of ITER for diverting funding that they believe could be used for their potentially more reasonable and/or cost effective fusion power plant designs. Criticisms levied often revolve around claims of the unwillingness by ITER researchers to face up to potential problems (both technical and economic) due to the dependence of their jobs on the continuation of tokamak research.
A French association including about 700 anti-nuclear groups, Sortir du nucléaire (Get Out of Nuclear Energy), claimed that ITER was a hazard because scientists did not yet know how to manipulate the high-energy deuterium and tritium hydrogen isotopes used in the fusion process.
Rebecca Harms, Green/EFA member of the European Parliament's Committee on Industry, Research and Energy, said: "In the next 50 years nuclear fusion will neither tackle climate change nor guarantee the security of our energy supply." Arguing that the EU's energy research should be focused elsewhere, she said: "The Green/EFA group demands that these funds be spent instead on energy research that is relevant to the future. A major focus should now be put on renewable sources of energy." French Green party lawmaker Noël Mamère claims that more concrete efforts to fight present-day global warming will be neglected as a result of ITER: "This is not good news for the fight against the greenhouse effect because we're going to put ten billion euros towards a project that has a term of 30-50 years when we're not even sure it will be effective."
According to researchers at a demonstration reactor in Japan, a fusion generator should be feasible in the 2030s and no later than the 2050s. Japan is pursuing its own research program with several operational facilities exploring different aspects of practicability.
In the United States alone, electricity accounts for US$210 billion in annual sales. Asia's electricity sector attracted US$93 billion in private investment between 1990 and 1999. These figures take into account only current prices. With petroleum prices widely expected to rise, political pressure on carbon production, and steadily increasing demand, these figures will undoubtedly also rise as known oil reserves are depleted (see Peak oil). Proponents contend that an investment in research now should be viewed as an attempt to earn a far greater future return for the economy. Also, worldwide investment of less than US$1 billion per year into ITER is not incompatible with concurrent research into other methods of power generation, which in 2007 totaled US$16.9 billion.
Contrary to criticism, proponents of ITER assert that there are significant employment benefits associated with the project. ITER will provide employment for hundreds of physicists, engineers, material scientists, construction workers and technicians in the short term, and if successful, will lead to a global industry of fusion-based power generation.
Supporters of ITER emphasize that the only way to convincingly prove ideas for withstanding the intense neutron flux is to experimentally subject materials to that flux — one of the primary missions of ITER and the IFMIF, The purpose of ITER is to explore the scientific and engineering questions surrounding fusion power plants, such that it may be possible to build one intelligently in the future. It is nearly impossible to get satisfactory theoretical results regarding the properties of materials under an intense energetic neutron flux, and burning plasmas are expected to have quite different properties from externally heated plasmas. The point has been reached, according to supporters, where answering these questions about fusion reactors by experiment (via ITER) is an economical research investment, given the monumental potential benefit.
Furthermore the main line of research—the tokamak—has been developed to the point that it is now possible to undertake the penultimate step in magnetic confinement plasma physics research—the investigation of ‘burning’ plasmas in which the vast majority of the heating is provided by the fusion event itself. A detailed engineering design has been developed for a tokamak experiment which would explore burning plasma physics and integrate reactor relevant technology. In the tokamak research program, recent advances in controlling the internal configuration of the plasma have led to the achievement of substantially improved energy and pressure confinement in tokamaks—the so-called ‘advanced tokamak’ modes—which reduces the projected cost of electricity from tokamak reactors by a factor of two to a value only about 50% more than the projected cost of electricity from advanced light-water reactors. In parallel, progress in the development of advanced, low activation structural materials supports the promise of environmentally benign fusion reactors, and research into alternate confinement concepts is yielding promise of future improvements in confinement. Finally, supporters point out that other potential replacements to the current use of fossil fuel sources have environmental issues of their own. Solar, wind, and hydroelectric power all have a relatively low power output per square kilometer compared to ITER's successor DEMO which, at 2000 MW, should have an energy density that exceeds even large fission power plants.
The vacuum vessel is the central part of the ITER machine: a double walled steel container in which the plasma is contained by means of magnetic fields.
The ITER vacuum vessel will be the biggest fusion furnace ever built. It will be twice as large and 16 times as heavy as any previously manufactured fusion vessel: each of the nine torus shaped sectors will weigh between 390 and 430 tonnes. When all the shielding and port structures are included, this adds up to a total of 5,116 tonnes. Its external diameter will measure , the internal . Once assembled, the whole structure will be high.
The primary function of the vacuum vessel is to provide a hermetically sealed plasma container. Its main components are the main vessel, the port structures and the supporting system. The main vessel is a double walled structure with poloidal and toroidal stiffening ribs between thick shells to reinforce the vessel structure. These ribs also form the flow passages for the cooling water. The space between the double walls will be filled with shield structures made of stainless steel which is corrosion resistant and does not conduct heat well. The inner surfaces of the vessel will be covered with blanket modules. These modules will provide shielding from the high-energy neutrons produced by the fusion reactions and some will also be used for tritium breeding concepts.
The vacuum vessel has 18 upper, 17 equatorial and 9 lower ports that will be used for remote handling operations, diagnostic systems, neutral beam injections and vacuum pumping.
Category:Nuclear research centers Category:Fusion power Category:Fusion reactors Category:Research projects Category:Orphan initialisms Category:Tokamaks
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