International Thermonuclear Experimental Reactor Construction Research Articles

Controlled Fusion: Magnetic and Inertial, Promises and Pitfalls

As with biomass, hydro, solar and wind power, fusion power can also generate clean energy, using deuterium, an isotope of hydrogen, abundantly available in our oceans. Our sun uses hydrogen in a fusion process to generate power. It has been demonstrated that fusion power can be generated on earth, under carefully controlled conditions using deuterium and tritium instead of hydrogen. There are two fundamental approaches to controlled fusion: magnetic confinement fusion (MCF) first proposed at Princeton University in 1951, and inertial confinement fusion (ICF) that followed shortly thereafter, first proposed at the Lawrence Livermore Laboratories in 1970. Progress made on magnetic fusion led to the planning and construction of ITER (International Thermonuclear Experimental Reactor), expected to be completed in 2035. In this article, we explain the processes necessary to generate fusion power through MCF and ICF. Unlike nuclear power, as a practical means to generate electricity, controlled fusion has presented the technical/scientific community with a plethora of very difficult challenges. It is only recently, after decades of intense research in many laboratories worldwide, that we have begun to see devices being built on a fusion reactor scale and hence the design of ITER. The challenges are many but require patience and perseverance.

Synchronized fusion development considering physics, materials and heat transfer

Significant achievements have been made in the last 60 years in the development of fusion energy with the tokamak configuration. Based on the accumulated knowledge, the world is embarking on the construction and operation of ITER (International Thermonuclear Experimental Reactor) with a production of 500 MWf fusion power and the demonstration of physics Q = 10. ITER will demonstrate D–T burn physics for a duration of a few hundred seconds to prepare for the next long-burn or steady state nuclear testing tokamak operating at much higher neutron fluence. With the evolution into a steady state nuclear device, such as the China Fusion Engineering Test Reactor (CFETR), it is necessary to examine the boundary conditions imposed by the combined development of tokamak physics, fusion materials and fusion technology for a reactor. The development of ferritic steel alloys as the structural material suitable for use at high neutron fluence leads to the use of helium as the most likely reactor coolant. This points to the fundamental technology limitation on the removal of chamber wall maximum heat flux at around 1 MW m−2 and an average heat flux of 0.1 MW m−2 for the next test reactor. Future reactor performance will then depend on the control of spatial and temporal edge heat flux peaking in order to increase the average heat flux to the chamber wall. With these severe material and technological limitations, system studies were used to scope out a few robust steady state synchronized fusion reactor (SFR) designs. As an example, a low fusion power design at 131.6 MWf, which can satisfy steady state design requirements, would have a major radius of 5.5 m and minor radius of 1.6 m. Such a design with even more advanced structural materials like Wf/W composite could allow higher performance and provide a net electrical production of 62 MWe. These can be incorporated into the CFETR program.

ITER on the road to fusion energy

On 21 November 2006, the government representatives of China, the European Union, India, Japan, Korea, Russia and the United States firmly committed to building the International Thermonuclear Experimental Reactor (ITER) [1] by signing the ITER Agreement. The ITER Organization, which was formally established on 24 October 2007 after ratification of the ITER Agreement in each Member country, is the outcome of a two-decade-long collaborative effort aimed at demonstrating the scientific and technical feasibility of fusion energy.Each ITER partner has established a Domestic Agency (DA) for the construction of ITER, and the ITER Organization, based in Cadarache, in Southern France, is growing at a steady pace. The total number of staff reached 398 people from more than 20 nations by the end of September 2009. ITER will be built largely (90%) through in-kind contribution by the seven Members. On site, the levelling of the 40 ha platform has been completed. The roadworks necessary for delivering the ITER components from Fos harbour, close to Marseille, to the site are in the final stage of completion. With the aim of obtaining First Plasma in 2018, a new reference schedule has been developed by the ITER Organization and the DAs. Rapid attainment of the ITER goals is critical to accelerate fusion development—a crucial issue today in a world of increasing competition for scarce resources.

Hydrogen implantation effect in copper alloys selected for ITER investigated by positron annihilation spectroscopy

Defects in the form of vacancies (loops, voids, etc) created by hydrogen implantation into selected Cu alloys foreseen for the International Thermonuclear Experimental Reactor (ITER) first wall cladding were studied using positron annihilation spectroscopy. The pulsed low-energy positron system, which enables depth profiling of the positron lifetime spectra in the near-surface region (20–460 nm) of hydrogen-implanted copper alloys, was applied, and its results were compared with TRIM calculations and transmission electron microscopy studies. The selected specimens were implanted in the Ion Beam Laboratory of FEI STU Bratislava. The energy of implantation was EH = 2 × 95 keV for the molecular ion beam. The temperature during this process was lower than 90°C. Two implantation doses were chosen for both the alloys: 1.3 × 1019 ions cm−2 (1.1 C cm−2) and 5 × 1018 ions cm−2 (0.4 C cm−2). Although the influences of neutrons with energy 14 MeV and protons with energy 95 keV are not the same (differences in energy and existence of proton charge), experimental simulation of radiation damage of ITER construction materials was successfully performed. The results are discussed in terms of microstructural changes of the studied materials upon irradiation. The CuAl25 alloy seems to be more resistant to proton bombardment than CuCrZr.

ITER site selection studies in Spain

The studies carried out to evaluate and select a candidate site for International Thermonuclear Experimental Reactor (ITER) construction in Spain are presented in this paper. The ITER design, completed in July 2001, considered a number of technical requirements that must be fulfilled by the selected site. Several assumptions concerning the ITER site were made in order to carry on the design before final site selection. In the studies undertaken for ITER site selection in Spain, the referred technical requirements and assumptions were applied across the whole of Spain and two areas were identified as being preferential. These areas are on the Mediterranean coast and are situated in the Catalan and Valencian regions. A comparative evaluation based on technical characteristics for the concrete plots, proposed within the preferential areas, has been done. The result of these studies was the selection of a site that was deemed to be the most competitive—Vandellós (Tarragona)—and it was proposed to the European Commission for detailed studies in order to be considered as a possible European site for ITER construction. Another key factor for hosting ITER in Spain, is the licensing process. The present status is summarised in this paper.

Status of fabrication development for plasma facing components in the EU

This paper summarises the European R&D efforts for the manufacture of shield modules and divertor cassettes for the International Thermonuclear Experimental Reactor (ITER), including their plasma facing components. The various development steps are described as they had to be taken to resolve the fabrication issues, and to keep track with the evolving design requirements and solutions. For all components, the manufacturing feasibility has been demonstrated on prototype scale which puts Europe in the position to start the procurement as soon as the decision about ITER construction is taken. The time period remaining until then is used to optimise the fabrication processes and to develop more cost effective alternatives.

Nuclear performance of the D–D phase of ITER

Deuterium plasma will be used during the early phase of the International Thermonuclear Experimental Reactor (ITER) operation. For a typical reduced cost ITER the D–D-neutron yield ∼3.5×10 18 n s −1 will be accompanied by a considerable tritium production and a D–T (14.1-MeV)-neutron yield of ∼0.7–3.5×10 18 n s −1. This paper describes the nuclear performance for the two-component neutron source experienced in the proposed advanced H-mode D–D regimes. The calculated nuclear energy release and residual activity estimates can be important from the radiation safety, maintenance and staged ITER construction standpoints.

Recommendations on the Nature and Level of U.S. Participation in the International Thermonuclear Experimental Reactor (ITER) Extension of the Engineering Design Activities

The Department of Energy (DOE) Office of Energy Research chartered through the Fusion Energy Sciences Advisory Committee (FESAC) a panel to “address the topic of U.S. participation in an ITER construction phase, assuming the ITER Parties decide to proceed with construction”. Given that there is expected to be a transition period of 3 to 5 years between the conclusion of the Engineering Design Activities (EDA) and the possible construction start, the DOE Office of Energy Research expanded the charge to “include the U.S. role in an interim period between the EDA and construction”.

Special Issue on Robotics and Mechatronics for Fusion Experimental Reactor (ITER)

Engineering design activities (EDA) demonstrating the science and technology for the International Thermonuclear Experimental Reactor (ITER), are being conducted based on the four-party international collaboration of Japan (JA), the U.S.A (US), Europe (EU), and Russia (RF). EDA basically concerns engineering design required for ITER construction and technical development confirming design feasibility. In engineering R&D design, the central role is being played by an International Joint Design Team (JCT) consisting of scientists and engineers from the four parties, conducting work on detailed component design, buildings and plant facilities design, safety analysis and evaluation, and comprehensive overall system design. In engineering R&D, whose final objective is to demonstrate engineering technology necessary for ITER construction, a wide variety of technical development ranging from data acquisition on material characteristics to verification of system performance is being conducted through equal participation of the four parties. Because of the importance of principal ITER components, such as superconducting coils, vacuum vessel, in-vessel components such as diverters and blankets, and remote maintenance equipment, a large-scale project has been set up for manufacturing prototypes, including full-scale models, and for demonstrating performance. In-vessel components such as blankets and divertors are exposed radioactivity of 14 MeV neutrons due to DT operation, and therefore must be maintained or replaced remotely. Plansbased on stage-by-stage ITER operation call for shielding blankets to be replaced by blankets for breeding tritium. Diverters require scheduled maintenance and replacement because they are subjected to severe plasma heat and particle loads. For in-vessel components that undergo scheduled maintenance, remote maintenance is an important technical issue that may affect the performance of ITER, so component structures and layout consistent with remote handling receive top priority and will be subjected to remote maintenance demonstration-testing of using full-scale models. Remote ITER maintenance focuses on technologies involving radiation-hard devices designed for a gamma radiation environment, remote operation and metrology and control for precisely handling heavy in-vessel payloads, and welding and cutting and inspection in narrow confines. Thus, use must be made of robot technologies in Japan and a design concept conceived that meets unique ITER needs. Because device handling precision, the working environment, and other factors surpass conventional technical levels, technical data on large-scale tokamaks, experience in handling heavy payloads in industry, and nuclear field environmental resistance must be studied and system development, including technical demonstrations, conducted on a full engineering scale. This is the backer of ITER device design and development. Good prospects exist for developing a large number of remote maintenance equipment satisfying ITER specifications through the development of a new remote maintenance concept that calls for the handling of heavy payloads with high precision, the acquisition of technical data confirming concept feasibility, the development of components having 2 to 3 times higher resistance to radiation than anything available previously, and the development of remote maintenance based tools that cut, weld, and inspect in narrow confines. In final development, steady progress is being made in fabricating, testing, and demonstrating full-scale remote maintenance. This Special Issue summarizes these achievements and provides an overview of the remote maintenance design on in-vessel components, introducing current status and plans on remote maintenance technology in which the Japan Home Teams is engaged in. Topics covered include the following: 1. Remote Maintenance Development for ITER 2. Blanket Remote Maintenance Development 3. Diverter Remote Maintenance Development 4. In-Vessel Metrology and Viewing Development 5. Pipe Welding and Cutting Tool Development 6. Pipe Inspection Tool Development 7. Thick-Plate Welding and Cutting Tool Development 8. Radiation-Hard Component Development 9. Standard Component Development 10. Data Acquisition and Control

ＩＴＥＲ用ガス冷却型５０ｋＡ電流リードの開発と実験結果

JAERI has developed 50kA current leads for the International Thermonuclear Experimental Reactor (ITER). The Center Solenoid (CS) Model Coil program is under way by means of international collaboration in ITER-EDA. The CS model coil is being developed for ITER CS coil and is for demonstration for ITER construction. The performance test of the CS model coil will be carried out at the JAERI ITER common test facility (CTF). The current lead consists of the vertical lead and the connection lead. The vertical lead is a vapor-cooled type and has a cable-in-conduit geometry. The vertical lead was designed with a heat leak of 1.2W/kA at a helium flow rate of 0.06g/(s·kA). The measured heat leak satisfied the designed value. The connection lead was made from copper pipe soldered with NbTi supreconducting wires. The pipe was stabilized by the supreconducting wires and a cooling channel. The current lead was operated up to 60kA. The design and the performance test results of 50kA current leads are reported. The results meet the specifications for the CS model coil test and for the ITER real machine.

Economic impacts on the united states of siting decisions for the International Thermonuclear Experimental Reactor

This paper presents the results of a study that examines and compares the probable short-term economic impacts of the International Thermonuclear Experimental Reactor (ITER) on the United States (U.S.) if (1) ITER were to be sited in the U.S., or (2) ITER were to be sited in one of the other countries that, along with the U.S., is currently participating in the ITER program. Life-cycle costs associated with ITER construction, operation, and decommissioning are analyzed to assess their economic impact. A number of possible U.S. host and U.S. non-host technology and cost-sharing arrangements with the other ITER Parties are examined, although cost-sharing arrangements and the process by which the Parties will select a host country and an ITER site remain open issues. Both national and local/regional economic impacts, as measured by gross domestic product, regional output, employment, net exports, and income, are considered. These impacts represent a portion of the complex, interrelated set of economic considerations that characterize U.S. host and U.S. non-host participation in ITER. A number of other potentially important economic and noneconomic considerations are discussed qualitatively.

The ITER project

ITER (the International Thermonuclear Experimental Reactor) is an international collaborative project aimed at demonstrating the scientific and technological feasibility of fusion energy for peaceful purposes. It is the next step for the magnetic fusion development programs of the four participants-the European Union, Japan, Russia, and the United States. This paper reports progress of the engineering design activities (EDA) for ITER. ITER's position in the four parties' fusion programs is outlined, the main elements of the design are introduced, and progress is summarized in physics and technology R&D that support the design activities. The outlook for the future is reviewed, particularly the desirability of making timely progress toward construction of ITER.

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.

Approaches to safety, environment and regulatory approval for ITER

International Thermonuclear Experimental Reactor (ITER) Engineering Design Activities (EDA) in safety and environment are approaching the point where conceptual safety design, topic studies and research will give way to project oriented engineering design activities. The Joint Central Team (JCT) is promoting safety design and analysis necessary for siting and regulatory approval. Scoping studies are underway at the general level, in terms of laying out the safety and environmental design framework for ITER. ITER must follow the nuclear regulations of the host country as the future construction site of ITER. That is, regulatory approval is required before construction of ITER. Thus, during the EDA, some preparations are necessary for the future application for regulatory approval. Notwithstanding the future host country's jurisdictional framework of nuclear regulations, the primary responsibility for safety and reliability of ITER rests with the legally responsible body which will operate ITER. Since scientific utilization of ITER and protection of the large investment depends on safe and reliable operation of ITER, we are highly motivated to achieve maximum levels of operability, maintainability, and safety. ITER will be the first fusion facility in which overall ‘nuclear safety’ provisions need to be integrated into the facility. For example, it will be the first fusion facility with significant decay heat and structural radiational damage. Since ITER is an experimental facility, it is also important that necessary experiments can be performed within some safety design limits without requiring extensive regulatory procedures. ITER will be designed with such a robust safety envelope compatible with the fusion power and the energy inventories. The basic approach to safety will be realized by ‘defense-in-depth’. The first priority will be in the prevention of accidents through the intrinsic features of the facility, quality assurance throughout, in design, construction, operation and maintenance, and appropriate provisions for human factors. Nevertheless, the plant will be designed to be ready for anomalous events. In addition, public will be protected with appropriate mitigative features, even for extremely unlikely and unforeseen hypothetical accidents to add safety margins as appropriate. Current safety design approaches are introduced in this paper, including a global methodology, off-normal plasma termination, decay heat removal, and containment and confinement strategies.

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.