International Thermonuclear Experimental Reactor Project Research Articles

The ITER project: status and prospects

The International Thermonuclear Experimental Reactor (ITER) is a fusion energy cooperative programme among the European Atomic Energy Community, the Governments of Japan, the Russian Federation and the United States of America. The main objective of the ITER Project is to achieve a controlled ignited burn time of 1000 seconds. The nominal fusion power is to be 1500 MW. During the first 10 years of operation the Basic Performance Phase, the machine should achieve typically a total of a few thousand hours of burn, while during the second phase, the Enhanced Performance Phase, a more extensive burn time is expected for material tests, energy extraction and tritium breeding tests. The machine is a tokamak and has a toroidal geometry. The plasma, with major and minor radii of respectively 8.1 and 2.8 m, will carry a current of 21 MA. The plasma current is induced and controlled by a set of large superconducting coils with a diameter up to 30 m. The confining toroidal magnetic field will be produced by a set of 20 large superconducting magnets with a total magnetic stored energy of 100 GJ and a maximum field at the winding of 12.5 T. The plasma and nuclear engineering features of the project are also described.

From MTR to ITER

In 1950, A D Sakharov and I E Tamm put forward the fundamental idea of magnetic thermal confinement of high-temperature plasma, and proposed the magnetic thermonuclear reactor (MTR) concept. Studies in this direction initiated the mammoth 'Tokamak' programme. After many years of persistent scientific and engineering efforts in many countries worldwide, the realisation of the thermonuclear reaction has now become available. The International Thermonuclear Experimental Reactor (ITER) project is currently being developed jointly by the European Community (Euroatom), Russia, USA, and Japan. The aim of the ITER reactor is to demonstrate the scientific and technological feasibility of the peaceful use of nuclear fusion energy. The reactor is based on the Tokamak concept.

The ITER Project

Letters from: [ Paul H. Rutherford ][1] [ Charles C. Baker ][1] Thomas H. Stix et al . take issue with the present course of the International Thermonuclear Experimental Reactor (ITER) initiative (Letters, 16 Feb., p. 891). ITER is a fusion research facility based on the highly successful “tokamak” approach to plasma confinement, now being designed under an international agreement executed in 1992 by the European Union, Japan, the Russian Federation, and the United States. ITER seeks to achieve, for the first time ever in controlled fusion research, a self-heated “burning” deuterium-tritium plasma. Plasma burn has been widely endorsed as a critically important and appropriate next step for fusion. Stix et al . question combining this step with three other “giant steps”: large size, long pulse, and superconducting magnets. The size of the ITER plasma is dictated by the requirement to provide sufficient energy confinement to reach the burning state; this is determined from size-scaling relationships derived from experiments on tokamaks with plasma volumes spanning two orders of magnitude; the largest of these tokamaks already operate at plasma densities and temperatures similar to those expected in ITER. Confinement in a tokamak is determined primarily by the magnitude of the plasma current: ITER's plasma current is about four times larger than that in the Joint European Torus. The step in pulse length is derived from the additional physics requirement to sustain the burn over times long compared with those characteristic of the evolution of plasma profiles. The step from copper to superconducting magnets has been found to be the most practical way of achieving the required pulse lengths. Superconducting magnets have already been used in tokamaks, including one of the size of Princeton's successful Tokamak Fusion Test Reactor. The long pulse and the superconducting magnets are also essential for ITER to advance fusion engineering objectives. The engineering features of ITER are generic to any fusion reactor; in ITER, they can be tested together in an integrated facility, made possible only by international partnership. Stix et al . also question the capability of the ITER design to achieve its stated technical objectives. Recognizing the need for broad technical consensus, a Technical Advisory Committee (TAC) was formed which, on a continuing basis, reports to the ruling ITER Council on the adequacy of the ITER design and its physics basis. The TAC's 16 members are drawn equally from all four partners, but they serve as individuals, independent of both the design team and their respective governmental agencies. Last July, the TAC completed a review of the “Interim Design” and, with unanimity, concluded that the design can fully meet ITER's mission and technical objectives. # {#article-title-2} The letters from Stix et al ., Ernesto Mazzucato, and William E. Parkins (16 Feb., p. 891) have two common themes, namely, that we should postpone or even cancel the ITER project and that we do not know how to make an attractive fusion reactor. Stix et al . and Mazzucato correctly note the tremendous progress that has been made in fusion research and that we are in a period where our expectations of continued progress are high. This is used as an argument to suggest that a commitment to the construction of ITER be postponed. I would argue just the opposite. We need to build on our excellent progress and take advantage of the unique opportunity offered by participation in ITER to move forward with fusion science and energy development. Projects like ITER are always faced with the idealistic argument that we should wait for better results. Such logic would have postponed most major undertakings that have lead to significant scientific and technological progress. The letters raise valid technical issues (including improved plasma confinement, control of disruptions, and engineering and materials development). These issues have been clearly recognized by fusion researchers, in general, and ITER, in particular. They are being responsibly addressed in the ITER research and development and base program activities. [1]: /lookup/doi/10.1126/science.272.5259.179e

ITER: the first experimental fusion reactor

The International Thermonuclear Experimental Reactor (ITER) project is a multiphased project, at present proceeding under the auspices of the International Atomic Energy Agency according to the terms of a four-party agreement between the European Atomic Energy Community, the Government of Japan, the Government of the USA and the Government of Russia (“the parties”). The project is based on the tokamak, a Russian invention which has been brought to a high level of development and progress in all major fusion programs throughout the world. The objective of ITER is to demonstrate the scientific and technological feasibility of fusion energy for commercial energy production and to test technologies for a demonstration fusion power plant. During the extended performance phase of ITER, it will demonstrate the characteristics of a fusion power plant, producing more than 1500 MW of fusion power. The objective of the engineering design activity (EDA) phase is to produce a detailed, complete and fully integrated engineering design of ITER and all technical data necessary for the future decision on the construction of ITER. The ITER device will be a major step from present fusion experiments and will encompass all the major elements required for a fusion reactor. It will also require the development and the implementation of major new components and technologies. The inside surface of the plasma containment chamber will be designed to withstand temperature of up to 500 °C, although normal operating temperatures will be substantially lower. Materials will have to be carefully chosen to withstand these temperatures, and a high neutron flux. In addition, other components of the device will be composed of state-of-the-art metal alloys, ceramics and composites, many of which are now in the early stage of development of testing. The main systems of ITER are the superconducting magnet coils and their support, the vacuum vessel and the shield-blanket, the heating and fueling systems, the cryostat, the power supplies and the buildings. During operation the ITER device will sustain a controlled fusion burn for periods of more than 1000 s. Numerous components, experimental packages and test modules will have to be remotely installed and removed from the ITER device in order to test materials properties, component characteristics and material lifetimes. The status of the ITER design as of July 1994 is presented below.

ITER: the first experimental fusion reactor

The International Thermonuclear Experimental Reactor (ITER) Project is a multi-phased project, presently proceeding under the auspices of the International Atomic Energy Agency according to the terms of a four-party agreement between the European Atomic Energy Community, the Government of Japan, the Government of the United States, and the Government of the Russian Federation. The project is based on the tokamak, a Russian invention which has been brought to a high level of development and progress in all major fusion programs throughout the world. The objective of ITER is to demonstrate the scientific and technological feasibility of fusion energy for commercial energy production and to test the technologies for a demonstration fusion power plant. During extended performance operaton ITER will be capable of producing more than 1000 MW (electric) of fusion power, an amount of power that is comparable with one of today's electricity generating plants. The objective of the Engineering Design Activities (EDA) phase is to produce the detailed, complete, and fully integrated engineering design of the tokamak and all technical data necessary for the construction of ITER. The ITER project will be a major step from present fusion experiments and will progress towards a fusion reactor. It will also require the development and implementation of major new components and technologies. The inside surfaces of the plasma containment chamber will be designed to withstand temperatures of up to nearly 500°C, although normal operating temperatures will be substantially lower. Materials will have to be carefully chosen to withstand these temperatures and a high neutron flux. In addition, other components of the device will be composed of state-of-the-art metal alloys, ceramics and composites, many of which are now in the early stages of development and testing. The main systems of ITER are the superconducting magnet coils and their support, the vacuum vessel and the shield/blanket, the heating, fueling systems, the cryostat, the power source and the buildings. During operation the ITER device will sustain a controlled fusion burn for periods of greater than 1000 s. Numerous components, experimental packages, and test modules will have to be remotely installed and removed from the ITER device in order to test materials properties, component characteristics and material lifetimes. This paper reviews the present status of the ITER design, its components and technologies.

Neutron and thermal calculation of blanket for high power operating condition of fusion reactor

As the international thermonuclear experimental reactor (ITER) project has proceeded to the engineering design activity (EDA) phase, the design parameters of the reactor have been reconsidered from those in the conceptual design activity (CDA) phase. The fusion power is one of the parameters being reconsidered. In the primitive assessment, the possibility of a fusion power of 1.5−3.0 GW was indicated. With simultaneous enlargement of the reactor dimensions, the neutron wall loading would be 1.2−2.3 times as high as that in the CDA phase. A tritium breeding blanket with ceramic breeder pebbles, proposed by Japan in the CDA phase, has been investigated for the accommodation of these high fusion powers. For a layered pebble bed-type blanket, the breeder and neutron multiplier layer thicknesses have been adjusted to allow a power variation from 1.5 to 3.0 GW. The neutron and thermal performance of the blanket design have been evaluated, and the tritium inventory in the blanket has been estimated. It has been shown that the layered pebble bed blanket is basically applicable to the high power operating conditions.

Industrial roles in the international thermonuclear experimental reactor (ITER) project

The International Thermonuclear Experimental Reactor (ITER) represents a major step toward realizing the benefits of magnetic fusion energy. Four international parties, the European Communities, Japan, the Russian Federation and the United States are collaborating on the design of ITER and the development of the relevant technology. Because the long range goal is to construct a demonstration reactor, and ultimately to develop fusion power on a commercial basis, there is worldwide emphasis on enhancing industrial involvement throughout the Engineering Design Activities (EDA).

Engineering and materials issues in designing a cold-gas divertor

One of the key challenges facing the International Thermonuclear Experimental Reactor (ITER) Project is the development of plasma-facing components (PFCs) that can withstand the severe environmental conditions at the plasma edge. The most intensely loaded element of the PFCs is the divertor. The divertor must handle high fluxes of energetic plasma particles and electromagnetic radiation without excessive impurity buildup in the plasma core. The “cold-plasma-target” mode of divertor operation proposed for ITER expands the divertor design window to include several alternate heat sink and armor materials that were not available for the previous “high recycling divertor” approach. In particular, beryllium armor can now be considered with copper, niobium and vanadium heat sink materials; and helium or liquid metal coolants are feasible in addition to water. This paper presents material properties and compatability assessments for these materials and coolants along with parametric studies of thermal and mechanical performance. A viable design window is found for copper and niobium heat sinks with beryllium armor, but not for vanadium unless thin (∼ 1 mm) coolant structures can be accomodated mechanically.

Engineering design activities (EDA) of the international thermonuclear experimental reactor (ITER) project: January 1993 progress report

The task of selecting and assembling the Joint Central Team (JCT) is the authors top priority, and he has instructed the Deputy Directors and Division Heads to diligently pursue the selection of qualified team members. Several steps are involved in assembling the JCT: specification of posts, nomination of candidates, selection of team members, arrival and startup of work, and completion of secondment procedures. Only after these steps have been completed are staff able to take up their full responsibilities within the management structure of the JCT. Even then, a period of some months of acclimatization and adjustment may be required before the staff can be expected to work fully effectively.

The physics of magnetic fusion reactors

During the past two decades there have been substantial advances in magnetic fusion research. On the experimental front, progress has been led by the mainline tokamaks, which have achieved reactor-level values of temperature and plasma pressure. Comparable progress, when allowance is made for their smaller programs, has been made in complementary configurations such as the stellarator, reversed-field pinch and field-reversed configuration. In this paper, the status of understanding of the physics of toroidal plasmas is reviewed. It is shown how the physics performance, constrained by technological and economic realities, determines the form of reference toroidal reactors. A comparative study of example reactors is not made, because the level of confidence in projections of their performance varies widely, reflecting the vastly different levels of support which each has received. Success with the tokamak has led to the initiation of the International Thermonuclear Experimental Reactor project. It is designed to produce 1500 MW of fusion power from a deuterium-tritium plasma for pulses of 1000 s or longer and to demonstrate the integration of the plasma and nuclear technologies needed for a demonstration reactor.

Overview of International Thermonuclear Experimental Reactor (ITER) engineering design activities*

The International Thermonuclear Experimental Reactor (ITER) [International Thermonuclear Experimental Reactor (ITER) (International Atomic Energy Agency, Vienna, 1988), ITER Documentation Series, No. 1] project is a multiphased project, presently proceeding under the auspices of the International Atomic Energy Agency according to the terms of a four-party agreement among the European Atomic Energy Community (EC), the Government of Japan (JA), the Government of the Russian Federation (RF), and the Government of the United States (US), ‘‘the Parties.’’ The ITER project is based on the tokamak, a Russian invention, and has since been brought to a high level of development in all major fusion programs in the world. The objective of ITER is to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes. The ITER design is being developed, with support from the Parties’ four Home Teams and is in progress by the Joint Central Team. An overview of ITER Design activities is presented.