ITER is an international
nuclear fusionNuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...
research and engineering project, which is currently building the world's largest and most advanced experimental
tokamakA tokamak is a device using a magnetic field to confine a plasma in the shape of a torus . Achieving a stable plasma equilibrium requires magnetic field lines that move around the torus in a helical shape...
nuclear fusion reactor at
CadaracheThe CEA Cadarache facility is a French scientific research centre which specialises in nuclear energy research. It is located in the commune of Saint-Paul-lès-Durance, Bouches-du-Rhône, in the southern region of Provence-Alpes-Côte-d'Azur...
in the south of
FranceThe French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. The ITER project aims to make the long-awaited transition from experimental studies of
plasmaIn physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
physics to full-scale electricity-producing
fusion powerFusion power is the power generated by nuclear fusion processes. In fusion reactions two light atomic nuclei fuse together to form a heavier nucleus . In doing so they release a comparatively large amount of energy arising from the binding energy due to the strong nuclear force which is manifested...
plants. The project is funded and run by seven member entities - the
European UnionThe European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
(EU),
IndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
,
JapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, the
People's Republic of ChinaChina , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
,
RussiaRussia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
,
South KoreaThe Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
and the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
. 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 confinementMagnetic confinement fusion is an approach to generating fusion power that uses magnetic fields to confine the hot fusion fuel in the form of a plasma. Magnetic confinement is one of two major branches of fusion energy research, the other being inertial confinement fusion. The magnetic approach is...
plasma physics experiment in use, surpassing the
Joint European TorusJET, the Joint European Torus, is the largest magnetic confinement plasma physics experiment worldwide currently in operation. Its main purpose is to open the way to future nuclear fusion experimental tokamak reactors such as ITER and :DEMO....
. The first commercial demonstration fusion power plant, named
DEMODEMO is a proposed nuclear fusion power plant that is intended to build upon the expected success of the ITER experimental nuclear fusion reactor. Whereas ITER's goal is to produce 500 megawatts of fusion power for at least 500 seconds, the goal of DEMO will be to produce at least four times that...
, is proposed to follow on from the ITER project to bring fusion energy to the commercial market.
Background
As
carbon-based fuelsFossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
grow
increasingly scarcePeak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline. This concept is based on the observed production rates of individual oil wells, projected reserves and the combined production rate of a field...
in the face of ever-growing demand, new and
more sustainableRenewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...
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,
deuteriumDeuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...
, can be extracted from
seawaterSeawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
, while the other fuel,
tritiumTritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...
, could possibly be created using neutrons produced in the fusion reaction itself. Furthermore, a fusion reactor would produce virtually no
CO2Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
or other atmospheric pollutants, and its other waste products would be very short-lived compared to those produced by conventional nuclear reactors.
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
CadaracheThe CEA Cadarache facility is a French scientific research centre which specialises in nuclear energy research. It is located in the commune of Saint-Paul-lès-Durance, Bouches-du-Rhône, in the southern region of Provence-Alpes-Côte-d'Azur...
,
FranceThe French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan 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
JETJET, the Joint European Torus, is the largest magnetic confinement plasma physics experiment worldwide currently in operation. Its main purpose is to open the way to future nuclear fusion experimental tokamak reactors such as ITER and :DEMO....
's peak of 16 MW for less than a second) by the fusion of about 0.5 g of
deuteriumDeuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...
/
tritiumTritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...
mixture in its approximately 840 m
3 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 "
experimentAn experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
al". "Iter" also means "journey", "direction" or "way" in
LatinLatin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
, reflecting ITER's potential role in harnessing
nuclear fusionNuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...
as a peaceful power source.
Organization history
ITER began in 1985 as a collaboration between the then
Soviet UnionThe Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
, the
European UnionThe European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
(through EURATOM), the
USAThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and
JapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. 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
CanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
(who then terminated their participation at the end of 2003), the
People's Republic of ChinaChina , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
and the Republic of Korea.
IndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
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 UnionThe European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
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:
- To momentarily produce ten times more thermal energy
Thermal energy is the part of the total internal energy of a thermodynamic system or sample of matter that results in the system's temperature....
from fusion heating than is supplied by auxiliary heating (a Q valueThe fusion energy gain factor, usually expressed with the symbol Q, is the ratio of fusion power produced in a nuclear fusion reactor to the power required to maintain the plasma in steady state. The condition of Q = 1 is referred to as breakeven.In a fusion power reactor a plasma must be...
of 10).
- To produce a steady-state plasma with a Q value
The fusion energy gain factor, usually expressed with the symbol Q, is the ratio of fusion power produced in a nuclear fusion reactor to the power required to maintain the plasma in steady state. The condition of Q = 1 is referred to as breakeven.In a fusion power reactor a plasma must be...
greater than 5.
- To maintain a fusion pulse for up to 480 seconds.
- To ignite a 'burning' (self-sustaining) plasma
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
.
- To develop technologies and processes needed for a fusion power plant — including superconducting magnet
A superconducting magnet is an electromagnet made from coils of superconducting wire. They must be cooled to cryogenic temperatures during operation. In its superconducting state the wire can conduct much larger electric currents than ordinary wire, creating intense magnetic fields...
s and remote handlingRemote handling is the synergistic combination of technology and engineering management systems to enable operators to safely, reliably and repeatedly perform manipulation of items without being in personal contact with those items.-Overview:...
(maintenance by robot).
- To verify tritium
Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...
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 |
| |
Seven participants formally agreed to fund the creation of a nuclear fusion reactor. |
| |
Site preparation start, ITER itinerary start. |
| |
Site preparation completion. |
| |
TokamakA tokamak is a device using a magnetic field to confine a plasma in the shape of a torus . Achieving a stable plasma equilibrium requires magnetic field lines that move around the torus in a helical shape...
complex excavation start. |
| |
Tokamak complex construction start. |
| |
Predicted: Tokamak assembly start. |
| |
Predicted: Tokamak assembly completion, start torusIn geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with the circle...
pumpdown. |
| |
Predicted: Achievement of first plasmaIn physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
. |
| |
Predicted: Start of deuterium-tritium operation. |
| |
Predicted: End of project. |
Reactor overview
When deuterium and tritium fuse, two
nucleiThe nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...
come together to form a
heliumHelium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
nucleus (an
alpha particleAlpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is classically produced in the process of alpha decay, but may be produced also in other ways and given the same name...
), and a high-energy
neutronThe neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
.
- + → + +
While nearly all stable isotopes lighter on the
periodic tableThe periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
than
iron-56Iron-56 is the most common isotope of iron. About 91.754% of all iron is iron-56.Of all isotopes, iron-56 has the lowest mass per nucleon. With 8.8 MeV binding energy per nucleon, iron-56 is one of the most tightly bound nuclei....
and
nickel-62Nickel-62 is an isotope of nickel having 28 protons and 34 neutrons.It is a stable isotope, with the highest binding energy per nucleon of any known nuclide . It is often stated that 56Fe is the "most stable nucleus", but actually 56Fe has the lowest mass per nucleon of all nuclides...
, which have the highest
binding energy per nucleonNuclear binding energy is the energy required to split a nucleus of an atom into its component parts. The component parts are neutrons and protons, which are collectively called nucleons...
, 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
protonThe proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
s in each nucleus will tend to strongly repel one another, as they each have the same positive
chargeThe elementary charge, usually denoted as e, is the electric charge carried by a single proton, or equivalently, the absolute value of the electric charge carried by a single electron. This elementary charge is a fundamental physical constant. To avoid confusion over its sign, e is sometimes called...
. A
heuristicHeuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...
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 forceThe nuclear force is the force between two or more nucleons. It is responsible for binding of protons and neutrons into atomic nuclei. The energy released causes the masses of nuclei to be less than the total mass of the protons and neutrons which form them...
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
KThe kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
. The plasma is heated to a high temperature by ohmic heating (running a current through the plasma). Additional heating is applied using
neutral beam injectionTo initiate a sustained fusion reaction, it is usually necessary to use many methods to heat the plasma, including RF heating, electron cyclotron resonance heating , ion cyclotron resonance heating , and neutral beam injection....
(which cross magnetic field lines without a net deflection and will not cause a large electromagnetic disruption) and
radio frequencyRadio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
(RF) or
microwaveMicrowaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
heating.
At such high temperatures, particles have a vast
kinetic energyThe kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
, 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 fieldA magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
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
energyIn physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
neutrons will radiate from the reactive regions of the plasma, crossing magnetic field lines easily due to charge neutrality (see
neutron fluxThe neutron flux is a quantity used in reactor physics corresponding to the total length travelled by all neutrons per unit time and volume . The neutron fluence is defined as the neutron flux integrated over a certain time period....
). 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
solenoidA solenoid is a coil wound into a tightly packed helix. In physics, the term solenoid refers to a long, thin loop of wire, often wrapped around a metallic core, which produces a magnetic field when an electric current is passed through it. Solenoids are important because they can create...
coil will use superconducting
niobium-tinNiobium-tin or triniobium-tin is a metallic chemical compound of niobium and tin , used industrially as a type II superconductor. This intermetallic compoundis a A15 phases superconductor...
to carry 46
kAThe ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...
and produce a field of 13.5
teslasThe tesla is the SI derived unit of magnetic field B . One tesla is equal to one weber per square meter, and it was defined in 1960 in honour of the inventor, physicist, and electrical engineer Nikola Tesla...
.
The 18
toroidalIn mathematics, a toroid is a doughnut-shaped object, such as an O-ring. Its annular shape is generated by revolving a plane geometrical figure about an axis external to that figure which is parallel to the plane of the figure and does not intersect the figure...
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-titaniumNiobium-titanium is an alloy of niobium and titanium, used industrially as a type II superconductor wire for superconducting magnets...
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 5km pipeline supplying water from Canal de Provence, and basins that allow cooling water to be cooled and tested for chemical contamination and
tritiumTritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...
before being released into the Durance River. This system will need to dissipate an average power of 450MW during the tokamak's operation. A
liquid nitrogenLiquid nitrogen is nitrogen in a liquid state at a very low temperature. It is produced industrially by fractional distillation of liquid air. Liquid nitrogen is a colourless clear liquid with density of 0.807 g/mL at its boiling point and a dielectric constant of 1.4...
system will provide a further 1300KW of cooling to 80 degrees Kelvin, and a
liquid heliumHelium exists in liquid form only at extremely low temperatures. The boiling point and critical point depend on the isotope of the helium; see the table below for values. The density of liquid helium-4 at its boiling point and 1 atmosphere is approximately 0.125 g/mL Helium-4 was first liquefied...
system will provide 65KW of cooling to 4.5 degrees Kelvin.
Location
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
Rokkashois a village located in the Kamikita District of northeastern Aomori Prefecture in the Tōhoku region of Japan. As of 2009, the village had an estimated population of 10,890 and a density of 43 persons per km². Its total area was 253.01 km².-Geography:...
,
Aomoriis a prefecture of Japan located in the Tōhoku Region. The capital is the city of Aomori.- History :Until the Meiji Restoration, the area of Aomori prefecture was known as Mutsu Province....
, Japan. Additionally,
CanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
announced a bid for the site in Clarington in May 2001, but withdrew from the race in 2003.
SpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
also offered a site at
Vandellòs*Vandellòs town*Vandellòs i l'Hospitalet de l'Infant municipality*Vandellòs Nuclear Power Plant...
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
MoscowMoscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...
on 28 June 2005, the participating parties agreed to construct ITER at
CadaracheThe CEA Cadarache facility is a French scientific research centre which specialises in nuclear energy research. It is located in the commune of Saint-Paul-lès-Durance, Bouches-du-Rhône, in the southern region of Provence-Alpes-Côte-d'Azur...
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 EnergyThe European Union's Joint Undertaking for ITER and the Development of Fusion Energy or Fusion for Energy is a European Union organisation known as a Joint Undertaking created under the Euratom Treaty by decision of the Council of the European Union...
, the EU agency in charge of the European contribution to the project, is located in
BarcelonaBarcelona is the second largest city in Spain after Madrid, and the capital of Catalonia, with a population of 1,621,537 within its administrative limits on a land area of...
, 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
Currently there are seven parties participating in the ITER program: the
European UnionThe European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
(through the legally distinct organisation EURATOM),
IndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
,
JapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
,
People's Republic of ChinaChina , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
,
RussiaRussia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
,
South KoreaThe Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
, and the United States of America (USA).
CanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
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
KazakhstanKazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...
'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 VelikhovEvgeny Pavlovich Velikhov is a physicist and scientific leader in the Russian Federation. His scientific interests include plasma physics, lasers, controlled nuclear fusion, power engineering and magnetohydrodynamics...
, initiator of ITER project.
Funding
, 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
MoscowMoscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...
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 LernerEric J. Lerner is an American popular science writer, independent plasma researcher, and serves as the president of Lawrenceville Plasma Physics, Inc...
, 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 nucléaireSortir du nucléaire is a French federation of about 800 anti-nuclear groups.Founded in 1997 as a result of the success of the struggle against the Superphénix, the organisation regularly campaigns against the use of nuclear power in France and in the world.In September 2007, 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
hydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
isotopes used in the fusion process.
Rebecca HarmsRebecca Harms is a German politician and Member of the European Parliament for Alliance '90/The Greens, part of the European Greens. In July 2009 she was elected as co-president of the The Greens–European Free Alliance group in the European parliament.Harms began her career as an apprentice...
, Green/EFA member of the
European ParliamentThe European Parliament is the directly elected parliamentary institution of the European Union . Together with the Council of the European Union and the Commission, it exercises the legislative function of the EU and it has been described as one of the most powerful legislatures in the world...
'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 MamèreNoël Mamère is a French singer, cyclist and politician.He rose to fame in the 1980s as a TV entertainer, in particular on Antenne 2....
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 wasteRadioactive wastes are wastes that contain radioactive material. Radioactive wastes are usually by-products of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine...
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 reactionNuclear meltdown is an informal term for a severe nuclear reactor accident that results in core damage from overheating. The term is not officially defined by the International Atomic Energy Agency or by the U.S. Nuclear Regulatory Commission...
. 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 CO
2 / SO
2 / 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 oilPeak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline. This concept is based on the observed production rates of individual oil wells, projected reserves and the combined production rate of a field...
). 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.
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. 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
tokamakA tokamak is a device using a magnetic field to confine a plasma in the shape of a torus . Achieving a stable plasma equilibrium requires magnetic field lines that move around the torus in a helical shape...
—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
tokamakA tokamak is a device using a magnetic field to confine a plasma in the shape of a torus . Achieving a stable plasma equilibrium requires magnetic field lines that move around the torus in a helical shape...
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.
SolarSolar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...
,
windWind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships....
, and
hydroelectricHydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
power all have a relatively low power output per square kilometer compared to ITER's successor
DEMODEMO is a proposed nuclear fusion power plant that is intended to build upon the expected success of the ITER experimental nuclear fusion reactor. Whereas ITER's goal is to produce 500 megawatts of fusion power for at least 500 seconds, the goal of DEMO will be to produce at least four times that...
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-VinçotteVinçotte is a Belgian accredited inspection and certification organisation, that controlled 75% of the Belgian safety, reliability market in 2004...
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 shapedIn geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with the circle...
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 (63.6 ft), the internal 6.5 metres (21.3 ft). Once assembled, the whole structure will be 11.3 metres (37.1 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
DEMODEMO is a proposed nuclear fusion power plant that is intended to build upon the expected success of the ITER experimental nuclear fusion reactor. Whereas ITER's goal is to produce 500 megawatts of fusion power for at least 500 seconds, the goal of DEMO will be to produce at least four times that...
,
Wendelstein 7-XWendelstein 7-X is an experimental stellarator currently being built in Greifswald, Germany by the Max-Planck-Institut für Plasmaphysik , which will be completed by 2015. It is a further development of Wendelstein 7-AS...
,
NIFThe National Ignition Facility, or NIF is a large, laser-based inertial confinement fusion research device located at the Lawrence Livermore National Laboratory in Livermore, California. NIF uses powerful lasers to heat and compress a small amount of hydrogen fuel to the point where nuclear fusion...
,
HiPERThe High Power laser Energy Research facility , is an experimental laser-driven inertial confinement fusion device undergoing preliminary design for possible construction in the European Union starting around 2010...
,
JETJET, the Joint European Torus, is the largest magnetic confinement plasma physics experiment worldwide currently in operation. Its main purpose is to open the way to future nuclear fusion experimental tokamak reactors such as ITER and :DEMO....
(precursor to ITER), and
MASTThe Mega Ampere Spherical Tokamak, or MAST experiment is a nuclear fusion experiment in operation at Culham, Oxfordshire, England since December 1999. It follows the highly successful START experiment...
.
See also
- Megaproject
A megaproject is an extremely large-scale investment project. Megaprojects are typically defined as costing more than US$1 billion and attracting a lot of public attention because of substantial impacts on communities, environment, and budgets. Megaprojects can also be defined as "initiatives that...
- Fusion for Energy
The European Union's Joint Undertaking for ITER and the Development of Fusion Energy or Fusion for Energy is a European Union organisation known as a Joint Undertaking created under the Euratom Treaty by decision of the Council of the European Union...
, the EU Agency in charge of the ITER project
- Nuclear power in France
Nuclear power is the primary source of electric power in France. In 2004, 425.8 TWh out of the country's total production of 540.6 TWh of electricity was from nuclear power , the highest percentage in the world....
- IFMIF
The International Fusion Material Irradiation Facility, also known as IFMIF, is an international scientific research program designed to test materials for suitability for use in a fusion reactor...
External links