ITER in perspective

Radiation shielding for superconductive toroidal field coils around the neutral beam injector duct in the ITER design

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.

The major purpose of the International Thermonuclear Experimental Reactor (ITER) is to develop an experimental fusion reactor for the scientific and technological feasibility demonstration of fusion power. ITER Conceptual Design Activites (CDA) began in the spring of 1988 through the united efforts of the European Community, Japan, the Soviet Union and the United States and ended in December 1990. The objectives of this phase were to develop the design of ITER, to perform a safety and environemental analysis, and to define, the future research and development. This paper gives the design concepts developed for the ITER basic devices such as containment structures, remote handling tools, superconducting coils and plasma facing components.

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).

ITER breeding blanket design for the enhanced performance phase

Consecutive absorption/desorption cycles of the ZrCo–H2 system were studied to simulate the real International Thermonuclear Experimental Reactor (ITER) hydrogen getter system. A ZrCo getter was used in this paper instead of the depleted uranium (DU) getter material, which has been recently considered as the hydrogen getter in ITER. In a cyclic pressure-composition isotherm (PCI) measurement, the high-pressure Sievert apparatus seems impractical to describe the equilibrium state of the ZrCo–H2 system in detail, especially for the desorption stage. This high-pressure PCI apparatus, however, shows cause and effect well, from the previous getter state to the following state in presenting hydriding/dehydriding performance. In case of the ZrCo–H2 system or in case of the DU–H2 system having multiple getter bed battery, a similar affection by previous getter status might be related and a similar aspect could be shown to consider further ITER design; for example, a need for control logic from PCI measurements using a high-pressure Sievert apparatus.

Effect of pressure on the radiation induced electrical conductivity of NBI insulator gases

Since the start of the ITER (International Thermonuclear Experimental Reactor) design effort, safety experts have attempted to guide designers in developing a machine that will demonstrate the potential safety and environmental advantages of fusion. Offsite dose limits (based on regulatory requirements) have been translated into release rates or radiological inventories, which provide useful guidance to designers. The ITER team is attempting to protect the public, to the extent possible, against major accidents with passive means, that is, without relying on active systems. The concept of passive safety is developed by the US safety team for internal events and for external events that are within the envelope of design-basis accidents selected for the ITER. In addition to overall safety guidance, implications of passive safety for ITER systems (as envisioned by the US safety team) are discussed. An approach to implementing passive safety in the ITER with reference to the blanket, plasma-facing components, fuel-cycle systems, plasma shutdown, and magnet design is described. The need for a confinement building is addressed, and the role of such a building in the context of passive safety is also discussed. >

The effects of a quench within the toroidal-field coil (TF) based on current International Thermonuclear Experimental Reactor (ITER) design are examined in a preliminary analysis. The intent is to assist ITER designers while more accurate computer codes are being developed, and to provide a check against these more rigorous solutions. Rigorous solutions to the quench problem are very complex, involving three-dimensional heat transfer, extreme changes in heat capacities and copper resistivity, and varying flow dynamics within the conductors. This analysis addresses all these factors in an approximate way. The result is much less accurate than a rigorous analysis; in fact, an error margin of as much as 30 to 40% is possible. However, it is believed that this analysis can still be very useful to the coil designer. Coil pressures and temperatures vs. time into a quench are presented. Rate of helium vent, energy deposition in the coil, and depletion of magnetic stored energy are also presented. Peak pressures are high (about 43 MPa). This is due to the very long vent path length (446 m), small hydraulic diameters, and high current densities associated with ITER's cable-in-conduit design. >

Mechanical Properties and Defective Effects of 316LN Stainless Steel by First-Principles Simulations

Estimates of energy supply versus consumption indicate the middle of this century as the critical point when world energy supply will no longer keep pace with the demand. The demand grows inexorably because of both the world population growth as well as the growth of average per capita energy consumption. Technological and economic progress are closely correlated with per capita energy consumption. Hence the inadequacy of energy supplies will limit the progress of human civilization, stifling its soaring spirit. Conservationism, making incremental improvements in this situation, is completely inadequate. What is needed is a giant step—the development of a new, limitless, clean source of energy—nuclear fusion energy. Nuclear fusion technology, when perfected to fusion-burn only deuterium, will have a fuel supply lasting millions of year, even with continuing energy consumption growth as in the past. Intensive efforts in five decades of Tokamak research has advanced the fusion product up by 107 times, to the point when breakeven is only a step away. The next step necessarily involves international collaboration on an unprecedented scale in ITER—the International Thermonuclear Experimental Reactor, on which work has started in Cadarache France. ITER and later Demo are envisioned to bring online the first commercial nuclear fusion energy reactor by 2050. Using this as the starting point and the history of the uptake of nuclear fission reactors as a guide, a scenario is described here which depicts a not unreasonable rapid take up of nuclear fusion energy starting after the middle of this century. Just into the next century fusion energy should be able to take up the slack and allow Mankind to continue its progress and growth. Because the development of fusion energy is such a complex technological task it is probable that there will be several decades when the constraints of energy shortage will be severely felt as shown by the flattening of the energy consumption from around 2040 to 2100. Such a period of stagnation seems unavoidable even with the envisaged development and rapid adoption of fusion energy. On the other hand without nuclear fusion energy the scenario depicts a severe downturn unavoidably in the fortunes of Mankind with world population shrinking below 5 billion and eventually even lower.

Code validation activities have been promoted inside the European fusion development agreement (EFDA) to test the capability of codes in simulating accident phenomena in fusion facilities and, specifically, in the International thermonuclear experimental reactor (ITER). This work includes a comparison between three different computer codes (CONSEN, MAGS and MELCOR) and one analytical model (ITER Model) in simulating cryogenic helium releases into the vacuum vessel (VV) which contains hot structures. The scope was the evaluation of the transient pressure inside the VV. The results will be used to design a vent duct (equivalent diameter, length and roughness) to allow pressure relief for the protection of the VV, which has a maximum design pressure of 200 kPa. The model geometry is a simplified scheme preserving the main features of the ITER design. Based on the results of the simulations, a matrix of experiments was developed to validate the calculated results and to design the vent duct for the ITER VV. The experiments are planned to be performed in the EVITA test facility, located in the CEA Cadarache research centre (France).

Full power operation of the International Thermonuclear Experimental Reactor (ITER) has been delayed and will now begin in 2035. Delays to the ITER schedule may affect the availability of tritium for subsequent fusion devices, as the global CANDU-type fission reactor fleet begins to phase out over the coming decades. This study provides an up to date account of future tritium availability by incorporating recent uncertainties over the life extension of the global CANDU fleet, as well as considering the potential impact of tritium demand by other fusion efforts. Despite the delays, our projections suggest that CANDU tritium remains sufficient to support the full operation of ITER. However, whether there is tritium available for a DEMO reactor following ITER is largely uncertain, and is subject to numerous uncontrollable externalities. Further tritium demand may come from any number of private sector “compact fusion” start-ups which have emerged in recent years, all of which aim to accelerate the development of fusion energy. If the associated technical challenges can be overcome, compact fusion programmes have the opportunity to use tritium over the next two decades whilst it is readily available, and before full power DT operation on ITER starts in 2035. Assuming a similar level of performance is achievable, a compact fusion development programme, using smaller reactors operating at lower fusion power, would require smaller quantities of tritium than the ITER programme, leaving sufficient tritium available for multiple concepts to be developed concurrently. The development of concurrent fusion concepts increases the chances of success, as it spreads the risk of failure. Additionally, if full tritium breeding capability is not expected to be demonstrated in DEMO until after 2050, an opportunity exists for compact fusion programmes to incorporate tritium breeding technology in nearer-term devices. DD start-up, which avoids the need for external tritium for reactor start-up, is dependent upon full tritium breeding capability, and may be essential for large-scale commercial roll-out of fusion energy. As such, from the standpoint of availability and use of external tritium, a compact route to fusion energy may be more advantageous, as it avoids longer-term complications and uncertainties in the future supply of tritium.

There is a need for a real time, reliable density measurement compatible with the restricted access and radiation environment on International Thermonuclear Experimental Reactor (ITER). Due to the large plasma path length, high density and field, refraction, and Faraday rotation effects makes the use of contemporary long wavelength (≳50 μm) interferometers impractical. In this paper we consider the design of a short wavelength vibration compensated interferometer which allows operation without a prohibitively large vibration isolated structure and permits the optics to be conveniently mounted directly in or on the tokamak. A density interferometer design for ITER incorporating a 10.6 μm CO2 interferometer with vibration compensation provided by a 3.39 μm HeNe laser is discussed. The proposed interferometer design requires only a small intrusion into the ITER tokamak without a large support structure, refraction and Faraday rotation problems are avoided, and it provides a density resolution of at least 0.5%. Results are presented from an interferometer installed on the DIII-D tokamak incorporating essential elements of the proposed ITER design including 10.6 and 3.39 μm lasers, a retroreflector mounted on the vacuum wall of the DIII-D tokamak and real-time density feedback control. In this paper we consider a short wavelength interferometer design that incorporates vibration compensation for use on ITER. Our primary concern is to develop an interferometer design that will produce a reliable real time density monitor. We use the ITER conceptual design activity report as the basis of the design.

The International Thermonuclear Experimental Reactor (ITER) is an international project aimed to build a fusion reactor using a plasma magnetic confinement (Tokamak) in Cadarache, France, which will demonstrate that such a machine can produce at least 10 times more energy than the one spent to sustain the fusion reaction. The project involves 7 partners: China, European Union (EU), India, Japan (JA), South Korea, Russian Federation and United States of America, all of whom will provide “in-kind” contributions to the central ITER Organization (IO) in the form of components required to build the machine. Each of the seven partners is represented by a Domestic Agency (DA) in order to comply with their in-kind contributions. The European Joint Undertaking for ITER and the Development of Fusion Energy or 'Fusion for Energy' (F4E) is a type of European organization known as a Joint Undertaking created under the Euratom Treaty by a decision of the Council of the European Union and it is the ITER European DA . F4E has three main objectives: a) Providing European contributions to the ITER international fusion energy research project being built in Cadarache, France; b) Providing European contributions to a number of joint projects with Japan that aim to accelerate the development of fusion - the Broader Approach; c) Coordinating a program of activities to prepare for the first demonstration fusion reactors that can generate electricity. ITER superconducting magnet system, working at 4.5K, consists of 18 Toroidal Field (TF) coils, 6 Central Solenoid (CS) modules, 6 Poloidal Field (PF) coils and 18 Correction Coils (CC). F4E is responsible for the procurement of about 25% of the magnet system. In this paper we are reporting on the main challenges to be faced during the manufacturing processes in terms of weld and their inspection.