ITER

International Thermonuclear Experimental Reactor
ITER's member states - the EU, India, Russia, China, South Korea, Japan and the United States.
Formation	1985
Headquarters	Cadarache, France
Website	iter.org

ITER (originally an acronym of International Thermonuclear Experimental Reactor) is an international nuclear fusion research and engineering project, which is currently building the world's largest and most advanced experimental tokamak nuclear fusion reactor at Cadarache in the south of France. The ITER project aims to make the long-awaited transition from experimental studies of plasma physics to full-scale electricity-producing fusion power plants. The project is funded and run by seven member entities - the European Union (EU), India, Japan, the People's Republic of China, Russia, South Korea and the United States. The EU, as host party for the ITER complex, is contributing 45% of the cost, with the other six parties contributing 9% each.

The ITER fusion reactor itself has been designed to produce 500 megawatts of output power for 50 megawatts 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 the first plasma is expected in 2019. When ITER becomes operational, it will become the largest magnetic confinement plasma physics experiment in use, surpassing the Joint European Torus. The first commercial demonstration fusion power plant, named DEMO, is proposed to follow on from the ITER project to bring fusion energy to the commercial market.

Background

As carbon-based fuels grow increasingly scarce in the face of ever-growing demand, new and more sustainable sources of energy will be necessary to meet global energy needs. 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, could possibly be created using neutrons produced in the fusion reaction itself. Furthermore, a fusion reactor would produce virtually no CO₂ or other atmospheric pollutants, and its other waste products would be very short-lived compared to those produced by conventional nuclear reactors.

On 21 November 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 eventually dropped due to the negative popular connotations of the word "thermonuclear", especially when used 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.

Organization history

ITER began in 1985 as a collaboration between the then Soviet Union, the European Union (through EURATOM), the USA, and Japan. Conceptual and engineering design phases 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. These parties (with the Russian Federation replacing the Soviet Union and with the USA opting out of the project in 1999 and returning in 2003) were joined in negotiations on the future construction, operation and decommissioning of ITER by Canada (who then terminated their participation at the end of 2003), the People's Republic of China and the Republic of Korea. India officially became part of ITER on 6 December 2005.

On 28 June 2005, it was officially announced that ITER will 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.

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 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. Specifically, the project aims:

• To momentarily produce ten times more thermal energy from fusion heating than is supplied by auxiliary heating (a Q value of 10).
• To produce a steady-state plasma with a Q value greater than 5.
• To maintain a fusion pulse for up to 480 seconds.
• To ignite a 'burning' (self-sustaining) plasma.
• To develop technologies and processes needed for a fusion power plant — including superconducting magnets and remote handling (maintenance by robot).
• To verify tritium breeding concepts.
• To refine neutron shield/heat conversion technology (most of energy in the D+T fusion reaction is released in the form of fast neutrons).

Timeline and current status

In 1978, the EC, Japan, USA 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. At the Geneva summit meeting in 1985, Secretary Gorbachev suggested to President 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. The history of the INTOR Workshop is documented in "Quest for a Fusion Energy Reactor: An Insider's Account of the INTOR Workshop", Oxford University Press (2010).

Launched in 1985, the ITER project was formally agreed to and funded in 2006 with a cost estimate of $12.8 billion (10 billion Euro) projecting the start of construction in 2008 and completion a decade later.

Timeline

Date	Event
2006-11-21	Seven participants formally agreed to fund the creation of a nuclear fusion reactor.
2008	Site preparation start, ITER itinerary start.
2009	Site preparation completion.
2010	Tokamak complex excavation start.
2011	Tokamak complex construction start.
2015	Predicted: Tokamak assembly start.
2018	Predicted: Tokamak assembly completion, start torus pumpdown.
November 2019	Predicted: Achievement of first plasma.
2026	Predicted: Start of deuterium-tritium operation.
2038	Predicted: End of project.

Reactor overview

See also: Nuclear fusion

When deuterium and tritium fuse, two nuclei come together to form a helium nucleus (an alpha particle), and a high-energy neutron.

2
1D + 3
1T → 4
2He + 1
0n + 17.6 MeV

While nearly all stable isotopes lighter on the periodic table than iron-56 and nickel-62, which have the highest binding energy per nucleon, will fuse with some other isotope and release energy, deuterium and tritium are by far the most attractive for energy generation as they require the lowest activation energy (thus lowest temperature) to do so, while producing among the most energy per unit weight.

All proto- and mid-life stars radiate enormous amounts of energy generated by fusion processes. Mass for mass, the deuterium-tritium fusion process releases roughly three times as much energy as uranium 235 fission, and millions of times more energy than a chemical reaction such as the burning of coal. It is the goal of a fusion power plant to harness this energy to produce electricity.

The activation energy for fusion is so high because the protons in each nucleus will tend to strongly repel one another, as they each have the same positive charge. A heuristic for estimating reaction rates is that nuclei must be able to get within 100 femtometer (1 × 10⁻¹³ meter) of each other, where the nuclei are increasingly likely to undergo quantum tunneling past the electrostatic barrier and the turning point where the strong nuclear force and the electrostatic force are equally balanced, allowing them to fuse. In ITER, this distance of approach is made possible by high temperatures and magnetic confinement. High temperatures give the nuclei enough energy to overcome their electrostatic repulsion (see Maxwell-Boltzmann distribution). For deuterium and tritium, the optimal reaction rates occur at temperatures on the order of 100,000,000 K. The plasma is heated to a high temperature by ohmic heating (running a current through the plasma). Additional heating is applied using neutral beam injection (which cross magnetic field lines without a net deflection and will not cause a large electromagnetic disruption) and radio frequency (RF) or microwave heating.

At such high temperatures, particles have a vast kinetic energy, and hence velocity. If unconfined, the particles will rapidly escape, taking the energy with them, cooling the plasma to the point where net energy is no longer produced. A successful reactor would need to contain the particles in a small enough volume for a long enough time for much of the plasma to fuse. In ITER and many other magnetic confinement reactors, the plasma, a gas of charged particles, is confined using magnetic fields. A charged particle moving through a magnetic field experiences a force perpendicular to the direction of travel, resulting in centripetal acceleration, thereby confining it to move in a circle.

A solid confinement vessel is also needed, both to shield the magnets and other equipment from high temperatures and energetic photons and particles, and to maintain a near-vacuum for the plasma to populate. The containment vessel is subjected to a barrage of very energetic particles, where electrons, ions, photons, alpha particles, and neutrons constantly bombard it and degrade the structure. The material must be designed to endure this environment so that a powerplant would be economical. Tests of such materials will be carried out both at ITER and at IFMIF (International Fusion Materials Irradiation Facility).

Once fusion has begun, high energy neutrons will radiate from the reactive regions of the plasma, crossing magnetic field lines easily due to charge neutrality (see neutron flux). Since it is the neutrons that receive the majority of the energy, they will be ITER's primary source of energy output. Ideally, alpha particles will expend their energy in the plasma, further heating it.

Beyond the inner wall of the containment vessel one of several test blanket modules will be placed. These are designed to slow and absorb neutrons in a reliable and efficient manner, limiting damage to the rest of the structure, and breeding tritium for fuel from lithium and the incoming neutrons. Energy absorbed from the fast neutrons is extracted and passed into the primary coolant. This heat energy would then be used to power an electricity-generating turbine in a real power plant; in ITER this generating system is not of scientific interest, so instead the heat will be extracted and disposed of.

Technical design

The central solenoid coil will use superconducting niobium-tin to carry 46 kA and produce a field of 13.5 teslas. The 18 toroidal field coils will also use niobium-tin. At their maximum field strength of 11.8 teslas, they will be able to store 41 gigajoules. They have been tested at a record 80 kA. Other lower field ITER magnets (PF and CC) will use niobium-titanium for their conducting elements.

Cooling systems

The ITER tokamak will use three interconnected cooling systems. Most of the heat will be removed by a primary water cooling loop, itself cooled by water through a heat exchanger within the tokamak building's secondary confinement. The secondary cooling loop will be cooled by a larger complex, comprising a cooling tower, a 5 km pipeline supplying water from Canal de Provence, and basins that allow cooling water to be cooled and tested for chemical contamination and tritium before being released into the Durance River. This system will need to dissipate an average power of 450 MW during the tokamak's operation. A liquid nitrogen system will provide a further 1300 kW of cooling to 80 Kelvin, and a liquid helium system will provide 65 kW of cooling to 4.5 Kelvin.

Location

Location of Cadarache in France, EU

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 to construct ITER at 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 2015.

Fusion for Energy, the EU agency in charge of the European contribution to the project, is located in Barcelona, Spain. Fusion for Energy (F4E) is the European Union’s Joint Undertaking for ITER and the Development of Fusion Energy. According to the agency's website:

"F4E is responsible for providing Europe’s contribution to ITER, the world’s largest scientific partnership that aims to demonstrate fusion as a viable and sustainable source of energy. [...] F4E also supports fusion research and development initiatives [...]"

Participants

All ITER partners (Cadarache and France highlighted)

Currently there are seven parties participating in the ITER program: the European Union (through the legally distinct organisation EURATOM), India, Japan, People's Republic of China, Russia, South Korea, and the United States of America (USA). Canada was previously a full member, but has since pulled out due to a lack of funding from the federal government. The lack of funding also resulted in Canada withdrawing from its bid for the ITER site in 2003. The host member of the ITER project, and hence the member contributing most of the costs, is the EU.

In 2007, it was announced that participants in the ITER will consider Kazakhstan's offer to join the program.

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.

Funding

As of 13 July 2010 (2010 -07-13), the total price of constructing the experiment is expected to be in excess of € 15 billion, an increase of € 5 billion from the 2009 estimate. Prior to that, the proposed costs for ITER were € 5 billion for the construction and € 5 billion for maintenance and the research connected with it during its 35 year lifetime. At the June 2005 conference in Moscow the participating members of the ITER cooperation agreed on the following division of funding contributions: 45% by the hosting member, the European Union, and the rest split between the non-hosting members – China, India, Japan, South Korea, the Russian Federation and the USA. During the operation and deactivation phases, Euratom will contribute to 34% of the total costs.

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 2/11ths of the research staff at Cadarache and be awarded 2/11ths of the construction contracts, while the European Union's staff and construction components contributions will be cut from 5/11ths to 4/11ths.

It was reported in December 2010 that the European Parliament had 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. The closure of the 2010 budget required this financing plan to be revised, and the European Commission (EC) was forced to put forward an ITER budgetary resolution proposal in 2011.

Criticism

The ITER project confronts numerous technically challenging issues. French Nobel laureate in physics, Pierre-Gilles de Gennes, said, "We say that we will put the sun into a box. The idea is pretty. The problem is, we don't know how to make the box."

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).

In 2005, Greenpeace International issued a press statement criticizing government funding of the ITER, believing the money should have been diverted to renewable and existing energy sources, like wind energy.

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."

Response to criticism

Proponents believe that much of the ITER criticism is misleading and inaccurate, in particular the allegations of the experiment's "inherent danger." The stated goals for a commercial fusion power station design are that the amount of radioactive waste produced be hundreds of times less than that of a fission reactor, that it produces no long-lived radioactive waste, and that it is impossible for any fusion reactor to undergo a large-scale runaway chain reaction. This is because direct contact with the walls of the reactor would contaminate the plasma, cooling it down immediately and stopping the fusion process. Besides which, the amount of fuel planned to be contained in a fusion reactor chamber (one half gram of deuterium/tritium fuel) is only enough to sustain the reaction for an hour at maximum, whereas a fission reactor usually contains several years' worth of fuel. In case of accident (or intentional act of terrorism) a fusion reactor releases far less radioactive pollution than an ordinary fission nuclear plant. Proponents note that large-scale fusion power — if it works — will be able to produce reliable electricity on demand and with virtually zero pollution (no gaseous CO₂ / SO₂ / NO_x by-products are produced).

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.^{[citation needed]} 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.

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, and both facilities will be of vital importance to the effort due to the differences in neutron power spectra between a real D-T burning plasma and the spectrum to be produced by 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.^{[citation needed]} 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.

Assessment of the vacuum vessel

ITER has decided to ask AIB-Vinçotte International (an inspection organization located in Belgium and accredited by the French Nuclear Authorities ASN) to assess the confinement (vacuum) vessel, the heart of the project, following the French Nuclear Regulatory requirements.

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 19.4 metres (64 ft), the internal 6.5 metres (21 ft). Once assembled, the whole structure will be 11.3 metres (37 ft) 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 60 millimetres (2.4 in) 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.

Similar projects

Other designs of fusion reactor are DEMO, Wendelstein 7-X, NIF, HiPER, JET (precursor to ITER), and MAST.

See also

• Megaproject
• Fusion for Energy, the EU Agency in charge of the ITER project
• Nuclear power in France
• IFMIF

External links

• Fusion for Energy, the EU Agency in charge of the ITER project
• ITER home page, includes pictures and diagrams available to use for educational purposes

• Beyond ITER The timescale to a commercial fusion power plant by 2050.
• ITER Technical Objectives

• ITER Organization Contacts directory for ITER staff and agencies.
• French Government ITER page
• ITER website in Belgium
• CEA ITER page
• Commission particulière du débat public Projet ITER (French site)
• EFDA home page
• IFMIF home page.
• U.S. ITER Project Office home page
• FIRE home page, with current news on ITER and other burning plasma developments
• Princeton Plasma Physics Laboratory
• The Fast Track To Fusion Power by Chris Llewellyn Smith of the UK Atomic Energy Authority
• ITER-NL Netherlands ITER industry portal (in Dutch)
• Climate Change Chronicles article about France winning the ITER contract
• ITER and ORNL
• Fusion reactors explained by HowStuffWorks
• Unofficial ITER fan club
• IPR Institute for Plasma Research
• What is a megaproject?
• European Commission Fusion Research