ITER : the energy of tomorrow
Air Liquide and ITER, at the border between industry and scientific research
ITER will explore the possibility of using fusion as a source of energy. The contributions of Air Liquide to this ambitious project reaffirm its expertise in state-of-the-art cryogenics. More fundamentally, these contributions consolidate its position as a preferred partner for large-scale global scientific projects and for the development of the energy solutions of tomorrow.
ITER stands for International Thermonuclear Experimental Reactor. In Latin, the word ITER means path or way. Last but not least, ITER is one of the avenues chosen by scientists to try and respond to the challenge of supplying humanity with sustainable energy. Against a backdrop of steadily rising energy needs, the exhaustion of non-renewable resources, and the likely indelibility of our negative environmental impact, ITER is exploring a sustainable, non-polluting solution to this challenge. The ITER program, carried by 7 members, where 35 states collaborate, is aimed to demonstrate the scientific and technological feasibility of fusion power for energy purposes. Nearly 30 years after the beginning of the international scientific collaboration, the reactor’s construction began in 2010, in Cadarache (France). The world’s biggest tokamak – with a plasma volume of 840 m3 – must still be assembled before the experiment actually launches, which is planned within the next ten years. The ITER program also integrates a Broader Approach, via complementary experimental projects outside of Cadarache, in order to make fusion a viable source of energy for humanity.
Cryogenics: expertise at the service of fusion
Extremely cold temperatures are required to create very strong electromagnetic fields, indispensable for the conditions of fusion. Air Liquide has substantial expertise in the area of very low temperatures. In addition, the company possesses recognized savoir-faire in the design, fabrication and installation of large capacity gas liquefaction and refrigeration systems. It has already completed impressive cryogenic installations, notably for the CERN’s Large Hadron Collider in Switzerland, which is the world’s largest liquid helium production unit, in Qatar, and the South Korean tokamak known as KSTAR. Thanks to the magnitude of these achievements and to the company’s earlier experiences in the field of fusion, the ITER project called on Air Liquide. First mission: provide ITER with a centralized helium cryogenic plant… the largest ever designed. Other requests followed, for cryogenic lines, or on behalf of the project’s Broader Approach. All in all, this adds up to an important acknowledgement of the industrial expertise of Air Liquide and the talents of its development teams.
"Cooling 10,000 tons of superconducting magnets that will control ITER’s plasma, is crucial to the success of this ambitious scientific challenge. Air Liquide will contribute to this success by providing some of the highly technical equipment."
The largest cryogenic plant
Cooling 10,000 tons of superconducting magnets that will confine the energy generating plasma is indispensable to the proper working of the ITER tokamak. The cryogenic factory dedicated to this end is a request from the ITER Organization and Fusion For Energy (F4E), the EU organization managing the European contribution to the ITER project. Its design, mobilizing more than 100 employees of Air Liquide, began in 2013 and is now in the fabrication phase. The Cadarache installation is scheduled for 2017. This impressive centralized cryogenic refrigeration system will be composed of helium (He) and nitrogen (N2) refrigeration units and dedicated storage, functioning in a closed loop. Helium, which is capable of reaching a temperature of close to absolute zero (-269°C, or 4.5K), will be used to cool magnets, vacuum pumps and certain diagnostic systems.
Nitrogen, whose temperature (-196°C, or 77K) is not quite as low, will contribute, among other things, to the cooling of the heat shield and the pre-cooling of the helium refrigeration unit and the helium loops. The site’s three helium units (LHe) will occupy 3,000 m2 of the 5,400 m2 set aside for the ITER cryogenic unit. LHe is composed of several compression stations and 3 large cold boxes, which weigh 135 tons each, measure 21 meters in length, and have a diameter of 4.2 meters.
On average, the helium refrigeration units will provide a global cooling capacity of 75kW to 4.5K, which translates into a maximum liquefaction rate of 12,300 liters/hour. They will be completed by two nitrogen units (LN2). The 11 helium and nitrogen gas storage units - with a total capacity of 3,700 m3 (of which 3,300 m3 for the helium) - will help to optimize the recovery of fluids in the various operational phases of the tokamak.
In nature, fusion is the energy source that fuels the stars. It results from collisions of hydrogen nuclei, which, under these extreme pressure and temperature conditions, free up a lot of energy. Under experimental conditions, fusion is carried out with hydrogen’s cousins, deuterium and tritium. The goal is to recover at least 10 times the energy consumed (Q 10). To do so, three conditions must be met: a temperature of around 150 M°C, great particle density, and long confinement of the energy. Fusion thus requires that gas be transformed into plasma. This is done inside a tokamak, where this hot plasma is confined and controlled by strong magnetic fields created by superconducting magnets. It is to ensure a temperature of close to absolute zero, indispensable for these superconductors, that ITER needs state-of-the-art cryogenics. About 80% of the energy released, carried by the neutron, is absorbed by the walls of the tokamak. This creates heat, which will produce steam, which in turn will be converted into electricity using turbines and alternators.
With high tech cryolines
Air Liquide’s experience on the CERN project led the ITER project to call on the company for another facet of the project. ITER-India, responsible for the successful execution of the project by India and responsible for the management of the corresponding equipment, asked Air Liquide to design and fabricate 19 cryogenic lines, which will complete the Cadarache cryogenic plant by distributing the cooling power needed for the ITER equipment to run. Dedicated to helium, this 1.6km long network will link the cryogenic plant to the tokamak between 2017 and 2019. Since some of the lines will need to function at temperatures close to absolute zero, the elaboration of a system like this requires a sophisticated design and the implementation of high tech fabrication processes.
State-of-the-art technology for state-of-the-art science
Projects of this scale demand innovations on the part of Air Liquide and its subsidiaries, both in terms of equipment design and in terms of their industrial production. Francois Darchis, member of the Air Liquide Executive Committee supervising Innovation, states: “The contribution of Air Liquide to the ITER program illustrates the level of confidence in the expertise and know-how of our teams in the area of very low temperatures, but also in the design and fabrication of large-capacity cryogenic units. The involvement of all the Group teams invested in ITER has already enabled us to pass the first milestones successfully.”
Head of Department Plant Engineering - ITER Organization
Could you explain in few words the ITER program?
ITER is the way to re-create the energy of the sun on the earth; this represents our major challenge. We are going to test the fusion reaction in order to produce approximately 500MW of power to attain an amplification factor of Q > = 10. This is a challenge that I am sure is achievable. It is for this reason that the plant has a complex configuration: nothing is usual, even the simplest things. Everything we do on ITER surpasses the current technological knowledge that we have collectively. We are achieving an important level of progress for humanity.
What is a tokamak? What is the cryogenics system interaction with the tokamak?
The tokamak is a Russian-origin technology using magnetic fields to confine fusion. The plasma reaction happens at 150 Millions°C, so the plasma reaction is confined in the center of the vacuum vessel. The ITER magnets will be cooled with helium at 4.5K (-269°C) in order to operate at the high magnetic fields necessary for the confinement of the plasma. They will be surrounded by a large cryostat and a thermal shield with a forced flow of helium at 80K (-193°C). A cryoplant on the ITER Platform will produce the required cooling power, and distribute it through a complex system of cryolines and cold boxes. All this is done by the cryogenics system.
Why have you selected Air Liquide as a supplier?
We were looking for a company that could assure, in the long term, the necessary assistance and capacity to manage such a complex system, ensuring the required flexibility – and that would also have an understanding of the variables that could change during the completion of the system design. We were also looking for a reliable partner in terms of financial solidity and technical knowledge and experience. Furthermore, the chosen company has to have the continuous flexibility to adapt to system changes and client’s requirements, as the cryogenic system is intended for the most important system of this plant being the magnets.
Could you talk about your partnership with Air Liquide?
Air Liquide is the major industrial partner that we have in ITER for the cryogenics system. Air Liquide’s team is fully involved in the design, procurement, installation and commissioning of the liquid helium system. It has been selected as an industrial partner also by Fusion For Energy for the nitrogen unit and auxiliary systems up to installation and commissioning. We are discussing the possibility of an integrated strategy for installation and how to manage properly the commissioning to assure proper operation of the system. For ITER, Air Liquide is an industrial partner and not just a supplier. We have succeeded in creating a very fruitful cooperation, which at the end we believe will bring solutions and positive results.
Air Liquide advanced Technologies contributes to the JT60SA, project, result of a collaboration between japan and Europe, on behalf of the CEA (the French Alternative Energies and Atomic Energy Commission) by supplying a helium refrigeration unit for the Japanese tokamak that should be done by the end of the year. Baptized JT-60SA, Japan Torus - Super Advanced, this tokamak is designed for the optimization of the performances, the control, and the duration of the plasma phases. It is paving the way for the pre-industrial reactor DEMO, the successor to ITER. The challenge is to satisfy Japanese standards pertaining to seismicity.
IFMIF (International Fusion Materials Irradiation Facility), currently in the EVEDA (Engineering Validation and Engineering Design Activities) phase, is one of the three pillars of the broader approach between Europe and Japan. This source of neutrons, located in Rokkasho (Japan), generated by an accelerator, was designed to test the materials under conditions simulating what actually happens inside a tokamak. Thus, it completes the ITER approach, preparing for the exploitation of fusion. Air Liquide provides the helium refrigerator that is indispensable to the success of this experiment.
AIR LIQUIDE AND ITER, AT THE BORDER BETWEEN INDUSTRY AND SCIENTIFIC RESEARCH
Tokamak: this Russian acronym means toroidal chamber with magnetic coils and designates an experimental machine designed to harness the energy produced through fusion. At the heart of the tokamak, a ring-shaped chamber houses the plasma, confined and controlled by very powerful magnetic fields, created by the extreme cooling of the superconductors.
Plasma: fourth state of matter, where the atoms of a gas separate into electrons and neutrons, achievable at very high temperatures.
Deuterium, Tritium: isotopes of hydrogen, each with one proton, but with one and two neutrons, respectively. Deuterium is widely available in nature. Naturally occurring tritium, which is radioactive, is relatively rare on Earth but is produced by reactions used in nuclear power plants. Its radioactivity only poses a danger if it is inhaled or ingested and, à priori, only to the cells that it penetrates.
Photos : L. Lelong, Air Liquide, ITER Organization, Zhangjiagang Furui Heavy Equipment CoBack to the homepage