°ÄÃÅÁùºÏ²Ê¸ßÊÖ

FAQs

Find answers to the most frequently asked questions about the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project.

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°ÄÃÅÁùºÏ²Ê¸ßÊÖ (the Latin word for "The Way") is a large-scale scientific experiment intended to prove the viability of fusion as an energy source. °ÄÃÅÁùºÏ²Ê¸ßÊÖ is currently under construction in the south of France. In an unprecedented international effort, seven partners—China, the European Union, India, Japan, Korea, Russia and the United States—have pooled their financial and scientific resources to build the biggest fusion reactor in history. °ÄÃÅÁùºÏ²Ê¸ßÊÖ will not produce electricity, but it will resolve critical scientific and technical issues in order to take fusion to the point where industrial applications can be designed. By producing 500 MW of fusion power from 50 MW of power injected in the systems that heat the plasma—a "gain factor" of 10—°ÄÃÅÁùºÏ²Ê¸ßÊÖ will open the way to the next step: a demonstration fusion power plant.

On-site construction of the scientific facility began in 2010. As the buildings rise at the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site in southern France, the fabrication of large-scale mockups and components is underway in the factories of the seven °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members. Component deliveries are accelerating and in May 2020, the first "piece" of the machine—the 1,250-tonne cryostat base—was introduced into the completed Tokamak pit. 

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is one of the most complex scientific and engineering projects in the world today. The complexity of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ design has already pushed a whole range of leading-edge technologies to new levels of performance. However, further science and technology are needed to bridge the gap to the commercialization of fusion energy.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is the experimental step between today's fusion machines, focused on plasma physics studies, and tomorrow's fusion power plants.

The plasma physics community will have access for the first time, in °ÄÃÅÁùºÏ²Ê¸ßÊÖ, to a burning plasma. In a burning plasma, the energy of the helium nuclei produced by the fusion reactions is enough to maintain the temperature of the plasma, thereby reducing or eliminating the need for external heating. Self-heating plasmas will be the key in the future to producing electricity from fusion energy, allowing for sustained, ongoing fusion reactions.

To be able to create plasmas with dominant self-heating, °ÄÃÅÁùºÏ²Ê¸ßÊÖ will be twice as large as the largest tokamak fusion experiment currently operating, (Europe/Japan), with six times the plasma volume. This unique experimental machine has been designed to:

  • Confine a deuterium-tritium plasma in which alpha-particle heating (self-heating) dominates
  • Generate 500 MW of fusion power in its plasma from 50 MW of heating input power (Q≥10) for long durations (400 to 600 seconds)
  • Contribute to the demonstration of the integrated operation of technologies for a fusion power plant
  • Test concepts for a tritium breeding module
  • Demonstrate the safety characteristics of a fusion device
  • Fusion is a promising option long-term for sustainable, global energy supply if the remaining technical challenges can be overcome.

In a project of this unprecedented scale, involving worldwide cooperation and billions of euros of expenditure, it would be naïve to believe that there could be unanimity in the scientific community on the aims and the scientific and technical basis of the project. A scientific consensus may be possible while discussions remain at the abstract level, but in a world of intense competition for research funding it is inevitable that scientists from various fields will criticize the decision to spend money on a large project, arguing that they would prefer to spend the money elsewhere.

What can be said about °ÄÃÅÁùºÏ²Ê¸ßÊÖ is that for the scientific community working in the energy field, this project is considered by a strong majority as a major step toward providing a future energy alternative for all humankind. The present political and scientific approach to this project has not suddenly appeared out of lobbying by a few influential individuals. It is the result of decades of painstaking, step-by-step research by fusion scientists all over the world as well as intense discussions in the scientific administrations of involved governments who debated the options, the costs and the risks before deciding that °ÄÃÅÁùºÏ²Ê¸ßÊÖ was a worthwhile investment in our common energy future. The proportion of papers directly concerned with °ÄÃÅÁùºÏ²Ê¸ßÊÖ presented at leading international scientific conferences on fusion as well as in fusion journals has been steadily increasing for a number of years. The fact that research aimed at °ÄÃÅÁùºÏ²Ê¸ßÊÖ is now such a dominant topic in these papers demonstrates how essential the project is to the advancement of fusion towards energy production.

While °ÄÃÅÁùºÏ²Ê¸ßÊÖ's future operation as a burning plasma device is clearly the core of °ÄÃÅÁùºÏ²Ê¸ßÊÖ's mission and the most anticipated outcome of the project, it is also important to point out the benefits realized so far during the design, construction, manufacturing and installation/assembly phases. Hundreds of engineering challenges associated with °ÄÃÅÁùºÏ²Ê¸ßÊÖ's many first-of-a-kind components have already been overcome, demanding innovation and engineering breakthroughs from some of the top laboratories and companies globally. In that sense, the global °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project is already a learning laboratory. Anecdotally, many within the global fusion R&D community report that the surge in private sector fusion projects, and the associated investment, has been driven by °ÄÃÅÁùºÏ²Ê¸ßÊÖ's success in these early phases.

Fusion research, and the role of °ÄÃÅÁùºÏ²Ê¸ßÊÖ, has been subject to serious scrutiny by panels of independent experts established by funding agencies in Europe and most of the other °ÄÃÅÁùºÏ²Ê¸ßÊÖ partners. The results of these investigations provide the most reliable measure of consensus in the scientific community. A few examples:

  • In 2004 during the early stages of °ÄÃÅÁùºÏ²Ê¸ßÊÖ negotiations, a high-level panel chaired by Sir David King (Chief Scientific Advisor to the UK government) concluded that the time was right to press ahead with °ÄÃÅÁùºÏ²Ê¸ßÊÖ and recommended funding a "fast track" approach to fusion energy. In 2013 the European Fusion Development Agreement (EFDA, now ) published The European Research Roadmap to the Realisation of Fusion Energy by 2050. The roadmap was in 2018. 
  • The French Academy of Sciences organized a detailed review of the state-of-the-art and the remaining challenges of fusion both by magnetic confinement (including °ÄÃÅÁùºÏ²Ê¸ßÊÖ) and using laser-driven systems. The review was in a book in 2007 which emphasized the arguments supporting the construction of °ÄÃÅÁùºÏ²Ê¸ßÊÖ.
  • The United States went through a long process to decide to re-enter the °ÄÃÅÁùºÏ²Ê¸ßÊÖ collaboration, after leaving it in the late 1990s. The US National Academy of Sciences convened a panel which included both fusion scientists and senior scientists from related fields such as nuclear fission power, high-energy physics and astrophysics. The non-fusion scientists were empowered to make the key recommendations. The panel strongly endorsed the renewed membership of the US in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project as the best path forward to fusion energy.
  • China announced in 2011 that it is planning to train 2,000 skilled experts over 10 years to carry out research and development in fusion. 
  • In May 2016, the US Department of Energy made a  to the US Congress in which it recommends that the US remain a partner in °ÄÃÅÁùºÏ²Ê¸ßÊÖ, through a re-assessment in 2018. Noting that "the management of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization and the performance of the project have improved substantially," the report concludes that despite accumulated delays, "°ÄÃÅÁùºÏ²Ê¸ßÊÖ remains the fastest path for the study of burning plasma."
  • In June 2017 the European Commission produced the 14-page document "" expressing confidence that the project was back on track.
  • In December 2017, the US National Academy of Sciences issued the first part of a two-phase study on the state and potential of magnetic fusion research in the US. In it, US policy makers were urged to continue to participate in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project and to develop a long-term strategy for fusion energy demonstration. (The report is available .)
  • In April 2018 the European Council of Ministers issued a statement mandating Commission to approve the new °ÄÃÅÁùºÏ²Ê¸ßÊÖ Baseline (cost, schedule, scope). One month later, the European Commission issued its 2021-2017 budget proposal with unequivocal support for the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project.
  • In 2019 the US National Academy of Sciences published its final report (available ), recommending not only that the US remain a partner in °ÄÃÅÁùºÏ²Ê¸ßÊÖ "as the most cost-effective way to gain experience with a burning plasma at the scale of a power plant," but also that it start a "national program of accompanying research and technology leading to the construction of a compact pilot plant."
  • In March 2020, hundreds of scientists across the United States—representing a broad range of national labs, universities, and private ventures—released A Community Plan for Fusion Energy and Discovery Plasma Sciences. It offers a consensus view of the bold steps to take nationally to deliver fusion energy and advance plasma science in the United States, including maintaining participation in °ÄÃÅÁùºÏ²Ê¸ßÊÖ. (Download the report .) The recommendations served as a basis for the final US Department of Energy, Fusion Energy Sciences Advisory Committee (FESAC) report , which was adopted in December 2020 and will now serve as advisory input to the DOE Office of Fusion Energy Sciences, which is responsible for all decisions and implementation.
  • At the request of the US Department of Energy (DOE), a committee of 12 scientists has written Bringing Fusion to the U.S. Grid, with the aim of providing guidance on the key goals and innovation needed to build an electricity-producing fusion power plant at lowest possible capital cost. The report, released in February 2021, calls for the construction of a 50-megawatt pilot fusion power plant. Download the full report . In December 2023, the DOE released .
  • The United Kingdom first set out a detailed strategy for fusion in 2021 and updated its strategy . The document is based on a two-pronged approach: building a prototype fusion power plant in the UK that delivers net energy (), and building up a world-leading fusion industry that supports different fusion technologies.
  • Recent publications make it clear that the governments of  (and also ),  (and also ),  (and also ), ,  (and also  and ),  (and ), and  are also actively pursuing long-term strategies for investment in fusion research. In early 2024, China the launch of a fusion consortium, Fusion Energy Inc, that aims to build an industrial prototype fusion reactor. In April 2024, Japan and the United States signed a  to accelerate fusion energy demonstration and commercialization.
  • Activity in the private sector is also accelerating, with at least 43 private fusion initiatives operating now in 12 countries, benefitting from more than USD 7 billion in private investment. (See resources below.)

See these general sources of information on global fusion energy initiatives: the , the IAEA Fusion Device Information System , the  (Fusion Industry Association) and (Fusion Industry Association).

 

The first small-size tokamaks (1950s-1970s) were basic devices without sophisticated control systems and technology, but they demonstrated that high temperature plasmas could be generated and that energy could be confined. New plasma phenomena such as anomalous transport, instabilities and disruptions were uncovered during these first experiments. Scaling laws indicated that energy confinement could be increased in larger devices with higher magnetic fields.

The second-generation, medium-sized devices in the 1980s introduced the extensive use of auxiliary heating techniques. The addition of the divertor demonstrated improved confinement; wall conditioning techniques were also introduced. The ASDEX Tokamak achieved high confinement mode for the first time in 1982.

A new generation of larger tokamaks—JET (Europe), JT-60 (Japan), TFTR (US), KSTAR (Korea) and T-15 (Soviet Union)—were built to study plasmas in conditions as close as possible to those of a fusion reactor, and regularly upgraded based on advances in fusion science. New features such as superconducting coils, deuterium-tritium operation, and remote handling were introduced. The experience accumulated on these machines contributed to the design of °ÄÃÅÁùºÏ²Ê¸ßÊÖ.

Today, fusion research is at the threshold of exploration of a "burning plasma" in which sufficient heat from the fusion reaction is retained within the plasma and sustains the reaction for a long duration. Such exploration is a necessary step toward the realization of a fusion energy source; it must be done to establish the confidence in proceeding with demonstrations of practical fusion energy. Construction of °ÄÃÅÁùºÏ²Ê¸ßÊÖ and implementation of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ research program would provide for such exploration.

Tokamaks around the world are helping to prepare for the construction and operation of °ÄÃÅÁùºÏ²Ê¸ßÊÖ. See more in International Tokamak Research.

Of the magnetic confinement concepts for fusion (mainly tokamaks and stellarators) the main advantage of °ÄÃÅÁùºÏ²Ê¸ßÊÖ and its tokamak technology is that, for the time being, the tokamak concept is by far the most advanced along the road to producing fusion energy. It is consequently pragmatism that dictated the choice of the tokamak concept for °ÄÃÅÁùºÏ²Ê¸ßÊÖ. Stellarators are inherently more complex than tokamaks (for example, optimized designs were not possible before the advent of supercomputers) but they may have advantages in reliability of operation. The Wendelstein 7-X stellarator, which celebrated its first plasma in 2015 in Greifswald, Germany, will allow good benchmarking against the performance of comparable tokamaks. These results will be incorporated in decisions about how DEMO, the next-generation fusion device after °ÄÃÅÁùºÏ²Ê¸ßÊÖ, will look.

The inertial fusion concepts are something quite different. These technologies have mainly been developed to simulate nuclear explosions and were not originally planned to produce fusion energy. The inertial fusion concept has not demonstrated so far that it offers a better or shorter path than magnetic confinement to energy production. However, interesting results were obtained in late 2022 in the National Ignition Facility (United States) when, for the first time, researchers successfully used 2.05 megajoules of laser energy to produce 3.15 megajoules of fusion energy, reaching a Q value of 1.5. (See more details here.) 

It should also be noted that in the last five years, a large number of private startups have entered the ring, raising an estimated USD 6 billion to develop alternative types of fusion reactors. Each one of these is contributing in some way to a shared goal: bringing fusion electricity to the grid.

 

The choice was made from the beginning to share the manufacturing of the most strategically important components among the seven °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members. This has considerably added to the complexity of the project, but the reasons for this decision were clear—by participating in °ÄÃÅÁùºÏ²Ê¸ßÊÖ, each Member is preparing its industrial infrastructure, its scientific base, and its physicists and engineers for the next step on the road to fusion power: the construction of a demonstration fusion power plant.

It seems clear that no one Member has the financial and technical resources to build °ÄÃÅÁùºÏ²Ê¸ßÊÖ alone. In this sense, by contributing only a portion of the project's costs, each Member benefits from the totality of the development program (where, already, there have been discoveries in technology, materials, science and even the first applications for patents) and, later, the totality of the 20-year experimental program. 

Collaboration and coordination between the different entities of the project is improving all of the time. What is remarkable about fusion research is that, for a very long time, it has been an international, collaborative venture where discoveries in one area of the world immediately benefit other research programs. This is true every day at °ÄÃÅÁùºÏ²Ê¸ßÊÖ, where the project benefits from the diverse experiences of its Members, including research underway on operational tokamaks in different parts of the world.

If °ÄÃÅÁùºÏ²Ê¸ßÊÖ were only a construction project, its model would certainly have been organized differently. But as the world's largest and most challenging energy research project, the collaboration between seven °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members—all with decades of experience in fusion—has been most profitable in terms of pooling resources to solve the difficult challenges that remain on the road to fusion.

In withdrawing from the European Union (EU) on 31 January 2020, the United Kingdom (UK) has also withdrawn from the European Atomic Energy Community (Euratom). Like all EU Member States, the UK had participated in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project through Euratom, which is the contracting party to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Agreement.

During the 11-month transition period through the end of the calendar year 2020, UK officials made clear that they wished to remain part of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project. 

On 30 December 2020, in parallel with the 1,246-page Trade and Cooperation Agreement signed by the United Kingdom and the European Union, a Nuclear Cooperation Agreement (NCA) was signed between the UK and Euratom (the European Atomic Energy Community), the legal entity through which Europe holds its membership in °ÄÃÅÁùºÏ²Ê¸ßÊÖ, that made clear the intent for the UK to remain a part of Fusion for Energy, the European Domestic Agency for °ÄÃÅÁùºÏ²Ê¸ßÊÖ. 

Negotiations came to an end in September 2023 when the United Kingdom announced that it would no longer pursue an association with Euratom, deciding instead "to pursue a domestic fusion energy strategy." The strategy includes the ambition to develop "close international collaboration," including with °ÄÃÅÁùºÏ²Ê¸ßÊÖ. Until the terms of possible association with °ÄÃÅÁùºÏ²Ê¸ßÊÖ are established, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project is in general no longer hiring UK citizens or contracting with UK companies; °ÄÃÅÁùºÏ²Ê¸ßÊÖ is however continuing to honour existing contracts.

Q—also called "fusion gain"—measures the ratio between the power produced by the fusion reactions, and the external heating power that must be injected in a tokamak to sustain the reactions.

Let's review how °ÄÃÅÁùºÏ²Ê¸ßÊÖ will create the conditions for fusion inside its vacuum chamber.

  • Fuel is injected in gaseous form into the vacuum vessel (the gas weighs only a few grams and fills the entire volume of the tokamak);
  • Electricity flowing through the electromagnets, particularly the central solenoid, produces a voltage across the gas;
  • This voltage rips electrons from the fuel atoms, turning them into charged particles (ions). This new state of matter is called a plasma;
  • The changing magnetic fields that are used to control the plasma produce a heating effect ("ohmic heating"). But in order to obtain the temperatures approaching 150,000,000 °C that are needed for deuterium-tritium fusion, three sources of external heating must be applied from outside of the tokamak;
  • The megawatts of heating power injected by these external systems is part of the ratio measured by Q, which compares input heating power to output fusion power.

In °ÄÃÅÁùºÏ²Ê¸ßÊÖ, the programmatic goal, Q≥10, signifies delivering ten times more thermal power (500 MW) than that which is delivered by the heating systems (50 MW).

Very. Breakeven, which corresponds to Q=1, is the moment when the total fusion power produced during a plasma pulse equals the power injected into the systems that heat the plasma. This has never been achieved in a magnetic confinement fusion device; the current record worldwide is held by the European tokamak JET (UK), which succeeded in generating a Q of 0.67 in the 1990s. °ÄÃÅÁùºÏ²Ê¸ßÊÖ is the machine that has been designed to do it, which explains the participation of so many nations—who run domestic fusion programs at home—in the international collaboration surrounding the project.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ's Q value of ≥10 makes it a first-of-kind machine and a unique scientific device. 

The fusion between the nuclei of the hydrogen isotopes deuterium (D) and tritium (T) produces one helium nucleus, also called an "alpha particle," and one neutron.

The helium nucleus, which carries 20 percent of the energy produced by the fusion reaction, is electrically charged and remains confined by the magnetic fields of the tokamak (whereas the neutron escapes). The heating provided by these alpha particles contributes to maintaining the temperature of the plasma and decreases the need for external heating. When heating by the helium nuclei ("alpha heating") is dominant (over 50 percent) the plasma is said to be a "burning plasma."

This is a state of matter that has never been produced in a controlled manner on Earth. Read more about it in this article.

Yes, it will, and there is a large worldwide consensus around the necessity of building such a device. Achieving a burning plasma in which at least 50 percent of the energy to drive the fusion reaction is generated internally through the alpha particles is an essential last step in the 70-year quest to control fusion reactions in a magnetic fusion device.

At Q = 5, approximately 50 percent of the plasma heating is contributed by the alpha particles. At Q = 10 (°ÄÃÅÁùºÏ²Ê¸ßÊÖ), this percentage rises to 66 percent. At Q=20 alpha heating represents 80 percent.

The primary motivation behind the design of °ÄÃÅÁùºÏ²Ê¸ßÊÖ is to provide Members' scientists with the opportunity to study, and better understand, a burning plasma. The knowledge acquired in °ÄÃÅÁùºÏ²Ê¸ßÊÖ will help scientists and engineers design the commercial fusion-generated electricity plants of the future. As a research device, °ÄÃÅÁùºÏ²Ê¸ßÊÖ will be equipped with far more diagnostics and other research components than the commercial facilities that will follow.

Accounting for the size of °ÄÃÅÁùºÏ²Ê¸ßÊÖ's vacuum vessel and the strength of the confining magnetic field (5.3 Tesla), the °ÄÃÅÁùºÏ²Ê¸ßÊÖ plasma (830 cubic metres) can carry a current of up to 15 megaamperes.

Under these conditions, an input thermal power of 50 megawatts is needed to bring the hydrogen plasma in the vessel to about 150 million degrees Celsius. This temperature in turn translates to a high enough velocity, among a sufficient population of hydrogen nuclei, to induce fusion at a rate that will produce at least 500 megawatts of thermal power output.

Why not design °ÄÃÅÁùºÏ²Ê¸ßÊÖ for a Q of 30, or 50? The answer is clear: expense. For tokamaks, size matters: if all other parameters are equal, larger size means greater Q. In simple terms, increasing Q would require an increase in the major radius or in the magnetic field strength. Either approach would have increased the cost of the device unnecessarily, whereas the achievement of Q ≥ 10 is sufficient to allow the primary scientific and technology goals of the project to be satisfied.

Plasma energy breakeven is the moment when the efficiency of the fusion reaction reaches Q = 1 (please see explanations on "Q" in the preceding paragraphs); that is, when the total fusion power produced during a plasma pulse equals the power injected into the systems that heat the plasma. This important scientific goal—never before achieved—is the "raison d'être" for the scale of °ÄÃÅÁùºÏ²Ê¸ßÊÖ and the design of many of its key technological systems (superconducting magnets, external heating, blanket, divertor, etc.).

Engineering breakeven would take into consideration all of the plants systems—and not just external heating systems—in the evaluation of the input/output power balance of an electricity-producing fusion power plant. Commercial fusion plants will be designed based on a power balance that accounts for the entire facility: the electricity output, sent to the industrial grid, compared to the electricity consumed by the facility itself—not only in tokamak heating, but also in secondary systems such as the electricity used to power the electromagnets, cool the cryogenics plant, and run diagnostics and control systems.

The main answer to this question comes from the nature of these two sciences and their technological applications. In terms of complexity (in both science and technology), there is more than one order of magnitude of difference between fusion and fission.

 

The core science of fusion is plasma physics, which is highly complex due to its non-linear and stochastic processes. The mastery of the physics is not yet sufficient to enable the construction of a fusion power plant, which requires cutting-edge technologies like superconductivity, high vacuum, and cryogenics. An important mission of °ÄÃÅÁùºÏ²Ê¸ßÊÖ is to prove once and for all that it is possible to integrate all these technologies into a single device. The technologies for fission, on the other hand, have evolved over generations of fission machines.

The next decades are crucially important to putting the world on a path towards much reduced greenhouse gas emissions. Current and near-term technologies should be deployed as soon as possible for this purpose. However world population will continue to grow and the proportion of populations living in cities is expected to continue to increase. Together with the need for a more equitable distribution of energy among the world's inhabitants, this means that even more large-scale, low-COâ‚‚ sustainable energy will be needed later in the century. 

The quest for fusion energy represents one of the most ambitious scientific and technological endeavours of our time. Fusion offers the promise of carbon-free, sustainable, large-scale energy, but realizing its potential requires overcoming significant scientific and engineering challenges. Among the most pressing are: the development of materials that are resistant to the harsh environment of a fusion reactor; the management of heat exhaust in the divertor region; the development of remote handling tools for maintenance and repair; the demonstration of large-scale tritium production and recycling; and the demonstration efficient heat removal for the production of electricity. (Read more about all these challenges on this page.)

°ÄÃÅÁùºÏ²Ê¸ßÊÖ will contribute to addressing each of them, in an integrated manner, but more R&D will be necessary for a demonstration reactor (usually called DEMO, for DEMOnstration fusion power plant). The presence of other publicly funded fusion research devices, combined with a surge in private sector projects, offers the opportunity to address some of these challenges in a complementary way, but only with enhanced transversal engagement. Continued R&D, international and multi-sector collaboration, and technological innovation will be crucial in overcoming the remaining challenges and to bringing fusion energy to fruition in the shortest time horizon possible.

The timescale to commercial fusion therefore depends strongly on the will to invest in this area of research. Lev Artsimovitch, the famous Russian academician and one of the major figures in fusion history, used to say: "Fusion will be ready when society needs it."
 

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is an essential bridge between today's smaller-scale experimental fusion devices and the demonstration fusion power plants of the future. Building on the knowledge and know-how acquired within °ÄÃÅÁùºÏ²Ê¸ßÊÖ, as well as research carried out in parallel on other fusion devices, the next-phase machines—industrial demonstrators generically referred to as DEMOnstration fusion reactors (DEMOs)—would demonstrate the large-scale production of electrical power and tritium fuel self-sufficiency. Several conceptual designs for such a machine are already on the table in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members; these designs will be refined as °ÄÃÅÁùºÏ²Ê¸ßÊÖ enters operations.

For more on the DEMO projects planned or underway, see this °ÄÃÅÁùºÏ²Ê¸ßÊÖ webpage.

Of course there are likely to be political and economic constraints that we cannot foresee. The final timescale to commercial fusion depends strongly on political and private sector will to invest in this area of research.
 

The power output of the kind of fusion power reactor that is envisaged for the second half of this century will be similar to that of a fission reactor, i.e., between 1 and 1.7 gigawatts. In theory, the larger the reactor, the more efficient it would be to operate and the more power it would produce, so it may be advantageous to go larger in the future. For the moment, it is envisaged that future fusion power plants would occupy buildings no bigger than those that presently house fission or coal-fired power stations.

The main goal of °ÄÃÅÁùºÏ²Ê¸ßÊÖ and future fusion reactor-based power plants is to develop a new source of clean and sustainable energy. The average cost per kilowatt of electricity can not yet be extrapolated, however, as this would require the operational experience which will only be available after °ÄÃÅÁùºÏ²Ê¸ßÊÖ has been operated for some years. As with many new technologies, costs will be more expensive at first, when the technology is new, and gradually less expensive as economies of scale bring the costs down.

In order to have a rapid market penetration, fusion will have to demonstrate the potential for competitive cost of electricity. Although this is not a primary goal for DEMO, the perspective of competitively priced electricity production from fusion has to be set as a target. One way to do this is to minimize DEMO capital costs (and that of fusion power plants). The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Tokamak is a first-of-a-kind experimental machine, built with a vast array of diagnostic systems (over 50!) to learn as much as possible about what is happening in the plasma. A fusion power plant on the other hand would be conceived in quite a different way.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ and future fusion devices will use the hydrogen isotopes deuterium and tritium to fuel the fusion reaction.

Deuterium can be distilled from all forms of water. It is a widely available, harmless, and virtually inexhaustible resource. In every cubic metre of seawater, for example, there are 33 grams of deuterium. Deuterium is routinely produced for scientific and industrial applications.

Tritium, however, is only present in nature in trace amounts. The only source of readily available tritium comes from heavy-water fission reactors such as the CANDU type (developed by Canada in the 1950-60s, and adopted since in Argentina, China, India, Pakistan, Romania, and South Korea). However, the tritium generated by these reactors is just a by-product and quantities remain relatively small. The accumulated stock of tritium produced from CANDU reactors worldwide does not exceed 20 kilos in any given year—just enough to fuel °ÄÃÅÁùºÏ²Ê¸ßÊÖ for the planned fifteen years of its deuterium-tritium operation phase.

Operating an industrial electricity-producing fusion plant, by contrast, will require an average of 70 kilos of tritium per gigawatt of thermal power (per year at full power). And if all goes well, there could be hundreds, if not thousands, of fusion plants operating in the early decades of the 22nd century. How then, will these reactors be fuelled?

Nature offers a solution that combines elegance and efficiency—if, successful, the fusion reaction itself will produce the tritium that, in turn, will continue to fuel the reaction. What's more, the process will take place within the vacuum vessel in a safe, continuous, closed cycle. The key to this process is isotope 6 of lithium (Li-6) which, when impacted by neutrons, generates tritium. °ÄÃÅÁùºÏ²Ê¸ßÊÖ will test different concepts of "tritium breeding modules," each one with a unique architecture and composition. Whether liquid or solid, compounds will consist of enriched lithium with a proportion of Li-6 in the 50 percent range (compared to the natural isotopic fraction of 7.5%).

Now we must ask: Will there be enough lithium to sustain tritium production for fusion?

Yes, enough for at least several thousand years. Let's look at the numbers. There are approximately 50 million tonnes of proven lithium reserves in the world (half in brine deposits, half in rocks), which means about 3 million tonnes of Li-6. Like most minerals, lithium is also present in seawater. At a concentration of 0.1 part per million, the mass of lithium contained in the oceans of the planet is estimated at 250 billion tonnes. However, a cost-effective method of recovering lithium from seawater does not yet exist.

It takes 140 kilos of Li-6 to obtain the 70 kilos of tritium necessary to producing one gigawatt of thermal power for one year. Assuming an availability of 80 percent and a conversion efficiency from thermal to electrical power of 30 percent, then the production of one gigawatt of electrical power (the estimated size of an average fusion reactor) will require approximately 500 kilos of Li-6 per year.

That brings the total requirement for 10,000 reactors to 5,000 tonnes of Li-6 annually.

Fusion will not be the only avid consumer of lithium. The ever-growing lithium-ion battery market for laptops, mobile phones, cordless power tools (and of course electrical vehicles) will claim its share. However lithium-ion batteries will not necessarily be in "competition" with fusion. At the scale of the global economy, one could imagine that the "waste" product of the lithium enrichment plants for fusion, namely Li-7, could well be used to produce lithium-ion batteries, thus maximizing the efficiency (and cost) of the overall lithium cycle.

Fusion specialists generally consider that, in a world where all energy would be produced by fusion, the quantity of lithium ore present in landmass would be sufficient to provide the required tritium for several thousand years. And as for the lithium present in oceans, it could last millions of years. As for the immediate needs of the tritium breeding module testing at °ÄÃÅÁùºÏ²Ê¸ßÊÖ, Li-6 enriched lithium will be supplied from existing lithium enrichment plants. The next fusion reactors such as DEMO will likely require new dedicated facilities to produce Li-6 enriched lithium in sufficient amounts.

Future fusion power plants will have to produce tritium; however, tritium self-sufficiency is not necessary in °ÄÃÅÁùºÏ²Ê¸ßÊÖ. Rather, one of the missions for the later stages of °ÄÃÅÁùºÏ²Ê¸ßÊÖ operation is to demonstrate the feasibility of several (4) concepts of tritium production through the Test Blanket Module (TBM) program. The TBM program will build on tritium breeding studies that have been carried out for a number of years, in particular by the European Union which has substantial expertise in this field. The accumulated knowledge permits a high level of confidence that results from °ÄÃÅÁùºÏ²Ê¸ßÊÖ will contribute to full tritium self-sufficiency in next-generation devices.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ and future fusion machines based on present superconductor technology would require only a fraction of the present total world helium production.

One of the major helium reserves is the US strategic helium storage reserve; this was released for sale and quantities will reduce in the coming years but will be compensated with new helium sources going into production around the world at the same time. There are also several other untapped helium reserves that ensure sufficient production for party balloons and MRI magnets (some of the main users of helium).

While it is uncertain what the price of helium will be in the coming decades (it will depend on supply and demand), there shouldn't be any significant shortage for fusion.

In the future, fusion machines will have the capability to breed not only their own fuel (tritium) but also helium to preserve natural reserves.

Fusion and fission are totally different scientific and technological concepts, although both involve nuclear reactions. The fuel assemblies in the core of a fission reactor contain several tons of radioactive fuel which generates energy by the splitting ("fissioning") of atomic nuclei in a chain reaction. Fusion is not a chain reaction. The entire system contains a few kilograms of the radioactive fuel component (tritium) with only a few grams reacting at any given time in the reaction chamber.

Three very unique safety features make fusion technology an attractive option to pursue for future large-scale electricity production.

First, fusion presents no risk of nuclear proliferation. Unlike the fissile materials such as uranium and plutonium used in fission reactors, tritium is neither a fissile nor a fissionable material. There are no enriched materials in a fusion reactor like °ÄÃÅÁùºÏ²Ê¸ßÊÖ that could be exploited to make nuclear weapons.

Second, nuclear fusion reactors would produce no high activity/long-life nuclear waste. The "burnt" fuel is helium, a non-radioactive gas. Radioactive substances in the system are the fuel (tritium) and materials activated while the machine is running. The goal of the ongoing R&D program is for fusion reactor material to be recyclable in less than 100 years.

Third, fusion reactions are intrinsically safe. A "runaway" reaction and the resulting uncontrolled production of energy is impossible with fusion. Fusion reactions cannot be maintained spontaneously: any disturbance or failure stops the reaction. This is why it is said that fusion has inherent safety aspects. Moreover, the loss of the cooling function due to an earthquake or flood would not affect the confinement barrier at all. Even in the case of the total failure of the water cooling system, °ÄÃÅÁùºÏ²Ê¸ßÊÖ's confinement barriers will remain intact. The temperatures of the vacuum vessel that provides the confinement barrier would under no circumstances reach the melting temperatures of the materials.

Nuclear risks associated with fusion relate to the use of tritium, which is a radioactive form (isotope) of hydrogen. However, the amount used is limited to a few grams of tritium for the reaction and a few kilograms on site. During operation, the radiological impact of the use of tritium on the most exposed population is much smaller than that due to natural background radiation. For °ÄÃÅÁùºÏ²Ê¸ßÊÖ, no accident scenario has been identified that would imply the need to take countermeasures to protect the surrounding population.

Along the road to the successful development of fusion, one of the major challenges will be to develop materials that can maintain their essential physical properties and not remain highly radioactive for extended periods of time after exposure to the harsh thermal and irradiation conditions inside a fusion reactor.

Fusion R&D has already successfully developed reduced-activation steels. Further developments are foreseen for steel as well as for other materials with more advanced features for fusion reactor applications.

EURATOM and Japan signed a Broader Approach agreement in 2007 that aims to complement the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project by carrying out R&D and developing some advanced technologies for future demonstration fusion power reactors (DEMO). Work is currently underway to complete the integrated engineering design of the International Fusion Materials Irradiation Facility (IFMIF) which will test and qualify advanced materials in an environment similar to that of a future fusion power plant.

The irradiated material will be transferred within a confinement cask to enclosed, shielded compartments ("hot cells"). Inside the hot cells, several operations will be performed such as cleaning and dust collection, detritiation, refurbishment, and disposal. The waste, which is classified as medium level, will be stored in the hot cells. All of these procedures are a part of °ÄÃÅÁùºÏ²Ê¸ßÊÖ operation as presented in the Preliminary Safety Report, and consequently are also submitted to examination of the French Nuclear Safety Authority.

Remote handling technologies have been developed for fusion applications, for example they have been extensively used in the recent upgrade of the Joint European Torus (JET) facility to ensure that workers are not exposed to radioactive components.

The fusion science community has an experience of more than twenty years operating large superconducting magnets, i.e., Large Helical Device (Japan), Tore-Supra (France).

 

Any loss of superconductivity is easily detected, and safety circuits place external resistors in series with the coils to absorb the stored energy. If the safety system and its backups were to fail the coils might suffer damage, but there is no possibility of threat to the integrity of the first confinement barrier.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is creating jobs, and not only locally.

First, consider the R&D and fabrication activities that are going on for °ÄÃÅÁùºÏ²Ê¸ßÊÖ around the world. In 2020, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Domestic Agencies estimated the number of contracts awarded related to the development and procurement of °ÄÃÅÁùºÏ²Ê¸ßÊÖ systems, components and infrastructure at over 3,200—the direct beneficiaries of these contracts are the laboratories, universities and industries in °ÄÃÅÁùºÏ²Ê¸ßÊÖ Member countries. (Contracts are also awarded directly by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization.) These contracts—many of which demand skilled contributions in engineering—are significantly more labour-intensive than conventional industrial manufacturing. An estimated EUR 4 billion are engaged in °ÄÃÅÁùºÏ²Ê¸ßÊÖ manufacturing around the world.

It is estimated that over three-fourths of the total European construction contribution to °ÄÃÅÁùºÏ²Ê¸ßÊÖ will be directed to industry, a proportion that is similar in other Members.

Over 1,000 people worked on the preparation of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site, the construction of the Provence-Alpes-Côte d'Azur International School, and the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Itinerary. A further 2,500 people were involved in °ÄÃÅÁùºÏ²Ê¸ßÊÖ construction for the period mid-2010 to 2014, and an average of 1,800 people for the period of 2014 to 2020. Today, approximately 6,500 people work for the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project in Saint Paul-lez-Durance (°ÄÃÅÁùºÏ²Ê¸ßÊÖ staff, contractors, temporary agents, European Domestic Agency staff and subcontractors, site workers); these employees contribute, with their families, to the economic life of the region.

Contracts totalling EUR 9.566 billion have been attributed since 2007 by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization, the European Domestic Agency for °ÄÃÅÁùºÏ²Ê¸ßÊÖ (responsible for the in-kind contribution of Europe to °ÄÃÅÁùºÏ²Ê¸ßÊÖ, including all buildings), and Agence Iter France. Within this total, companies in France have been awarded EUR 5.765 billion worth of contracts, of which 78% (worth EUR 4.516 billion) were attributed to companies based in the PACA region (statistics for the period ending 31 December 2023).

A carried out by the European Commission ("Follow up study on the economic benefits of °ÄÃÅÁùºÏ²Ê¸ßÊÖ and BA projects to EU industry", European Commission, 2021 confirmed that, for the period 2008 to 2019, the economic impact of °ÄÃÅÁùºÏ²Ê¸ßÊÖ on the EU economy has been positive. The incremental gross value added (i.e. the value of °ÄÃÅÁùºÏ²Ê¸ßÊÖ contributions less all inputs needed to produce them) equalled EUR 1.739 billion for the period considered. Cumulatively, the total number of full-time jobs directly or indirectly created by °ÄÃÅÁùºÏ²Ê¸ßÊÖ, in that period, reached nearly 29,500 in the EU. For every job that was directly created as a result of °ÄÃÅÁùºÏ²Ê¸ßÊÖ's activities, the study estimated that another job was indirectly created. Those indirect jobs typically emerged in the supply chains of °ÄÃÅÁùºÏ²Ê¸ßÊÖ, or as a result of °ÄÃÅÁùºÏ²Ê¸ßÊÖ-related wages being spent on other products and services.

 

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is under construction now in Saint Paul-lez-Durance, southern France. The buildings of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ scientific installation are mostly complete, and machine and plant assembly is underway

Under the previous Director-General, Bernard Bigot, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization and the Domestic Agencies conducted an eight-month, project-wide internal assessment in 2015 that scrutinized every detail of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ components and systems (from design, through manufacturing, delivery and assembly). The result—the best technically achievable project schedule and associated resource estimates—was presented to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council in November 2015 and subsequently reviewed by an independent group of Council-appointed experts.

In June 2016, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council endorsed the updated Resource-Loaded Integrated Schedule, through First Plasma; at its next meeting, in November 2016, it adopted the updated schedule through the start of Deuterium-Tritium Operation in 2035.

The Covid-19 pandemic has had a real effect on °ÄÃÅÁùºÏ²Ê¸ßÊÖ manufacturing (factory closures, personnel absences) and the transport of major components (international backlog), causing some delay against the Baseline 2016 schedule. Additionally, in November 2022, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization reported that it had discovered some technical defects in two critical tokamak components—the thermal shield, and the vacuum vessel sectors; since, extensive repairs have been undertaken. (See further detail here and here.) While these defects are repaired, vacuum vessel assembly is currently on hold. An updated °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project Baseline (scope, schedule and cost) was proposed to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council in June 2024 that takes into account recovery from Covid-induced delays, the repair of key components, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ licensing process, and an optimized plan for assembly and operation. (See this related article.)

Whereas the 2016 plan made a low-energy, low-current first plasma the first major milestone—to be immediately followed by a multiyear assembly period to install major in-vessel components—the delay offered the project a new way forward: starting operations with a more complete machine.

The new baseline has been designed to prioritize a robust start to scientific exploitation. With a divertor, blanket shield blocks and other key components and systems in place, °ÄÃÅÁùºÏ²Ê¸ßÊÖ's first operational phase, Start of Research Operation, will feature hydrogen and deuterium-deuterium plasmas that culminate in the operation of the machine in long pulses at full magnetic energy and plasma current.

The new baseline also includes more time for integrated commissioning, the testing of some magnet coils at 4 K (minus 269 ° C), additional heating, and the availability of disruption mitigation. The material for the plasma-facing blanket first wall is also changing from beryllium to tungsten. In the new plan, the achievement of full magnetic energy in 2036 represents a delay of three years relative to the 2016 reference, while the start of the deuterium-tritium operation phase in 2039 represents a delay of four years.

The new baseline proposal is under review by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council, which meets next in November 2024.

See more detail in this article in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Newsline.

The roads, bridges and roundabouts of the road Itinerary that leads to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site from the Mediterranean were modified by France to meet the needs of the exceptional convoys that will transport °ÄÃÅÁùºÏ²Ê¸ßÊÖ components arriving by sea.

The first Highly Exceptional Load (or HEL) travelled along the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Itinerary in January 2015; since then, approximately 150 HEL loads have been brought along the Itinerary to °ÄÃÅÁùºÏ²Ê¸ßÊÖ.

It is expected that, in total, that 250 exceptional convoys will have travelled along the Itinerary with their extra-large cargo by night, at reduced speeds, to deliver the components the project needs to complete machine assembly. The largest components transported to date are the 440-tonne vacuum vessel sectors, the 330-tonne toroidal field coils, the lowest poloidal field coil (PF6, nearly 400 tonnes), and some of the magnet feeders.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is being built collaboratively by the seven °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members.

During the construction phase of the project, Europe has responsibility for approximately 45.5 percent of construction costs, whereas China, India, Japan, Korea, the Russian Federation and the United States will contribute approximately 9.1 percent each. The lion's share (90 percent) of contributions are delivered "in-kind." That means that in the place of cash, the Members deliver components and buildings directly to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization.

The in-kind contributions of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members have been divided into approximately 140 Procurement Arrangements. These documents detail the technical specifications and management requirements for the procurement of plant systems, components or site construction. The value of each Procurement Arrangement is expressed in °ÄÃÅÁùºÏ²Ê¸ßÊÖ Units of Account (IUAs), a currency devised to measure the value of in-kind contributions to °ÄÃÅÁùºÏ²Ê¸ßÊÖ consistently over time.

Procurement allocations were assigned among the Members on the basis of valuations of components. Upon successful completion of a component, the corresponding credit value is credited to the Members' account. Contributing 9.1 percent of the project, therefore, becomes a matter of adding up the IUA value of the different contributions.

For the operation phase, the sharing of cost amongst the Members will be as follows: Europe 34 percent, Japan and the United States 13 percent, and China, India, Korea, and Russia 10 percent.

France contributes to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project as a member of the European Union. The country's commitment to °ÄÃÅÁùºÏ²Ê¸ßÊÖ "at the level of EUR 1.2 billion through to 2017" was confirmed by French Minister of Research and Higher Education Geneviève Fioraso on the occasion of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Headquarters inauguration (17 January 2013). Furthermore, France has contributed a number of in-kind contributions for a total of approximately EUR 260 million (°ÄÃÅÁùºÏ²Ê¸ßÊÖ site preparation, the International School in Manosque and the realization of the heavy haul Itinerary). The French financial and in-kind contributions originate from the French government as well as from the local governments of the Provence-Alpes-Côte d'Azur region where °ÄÃÅÁùºÏ²Ê¸ßÊÖ is located, who have pledged a total of EUR 467 million to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project over a period of 10 years.

This contribution is on par with the contracts and employment that have already been generated in the area by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project. (See section on Economic Benefits.)

For all Members, the potential benefits of participation are significant: by contributing a portion of the project's costs, Members benefit from 100 percent of the scientific results.

Based on the 2001 design, the original cost estimate of °ÄÃÅÁùºÏ²Ê¸ßÊÖ was EUR 5 billion for construction costs. This estimate, based on the best available information at the time, did not include some labour costs, escalation and contingency. It also did not properly estimate the time needed for the assembly and commissioning phases of the first-of-a-kind °ÄÃÅÁùºÏ²Ê¸ßÊÖ Tokamak, or include some later-term matters such as component storage.

In 2008, a detailed design review called for modifications to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ machine based on advancements in fusion science; these modifications, such as the addition of vertical stability and Edge Localization Mode (ELM) coils, were incorporated into the 2010 Baseline and added to overall cost. The fact that the number of °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members passed from four to seven also contributed to cost increases by creating a much larger number of interfaces (and hence, complexity) within the design. The third important element of the cost increase is that building construction costs have increased significantly since the 2001 estimate. Raw material costs have doubled (steel) or tripled (concrete).

In 2015, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization conducted an in-depth review and analysis of all aspects of manufacturing and assembly of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ systems, structures and components. The resulting updated schedule and overall cost estimate reflect a more advanced level of design maturity and a much-improved understanding of the scope, sequencing, risks, and costs of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project. The schedule exercise identifies December 2025 as the best technically achievable date for First Plasma and 2035 as the start of Deuterium-Tritium Operation. Both dates were set contingent on resources being available.

Since that time, technical challenges have been encountered in the manufacturing of °ÄÃÅÁùºÏ²Ê¸ßÊÖ's first-of-a-kind components. In many cases, those challenges have been resolved; in other cases, setbacks required repair. With the advent of the Covid-19 pandemic, it became clear that the 2016 Baseline could no longer be achieved. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization and the Domestic Agencies have now developed an updated baseline that they proposed to the 34th Meeting of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council in June 2024. The details of this proposal, including the increased cost and the schedule implications driven by this new approach, are under consideration by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is financed by seven Members: China, the European Union, India, Japan, Korea, Russia and the United States. In all, 35 countries are sharing the cost of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project.

Because multiple Members are collaborating to build °ÄÃÅÁùºÏ²Ê¸ßÊÖ, each with responsibility for the procurement of in-kind hardware in its own territory with its own currency, a direct conversion of the value estimate for °ÄÃÅÁùºÏ²Ê¸ßÊÖ construction into a single currency is not relevant.

Prior to the 2016 budget updating exercise, the European Union had estimated its global contribution to the costs of °ÄÃÅÁùºÏ²Ê¸ßÊÖ construction at EUR 6.6 billion, with other Domestic Agency contributions depending on the cost of industrial fabrication in those Member states, which can be higher or lower, and their percentage contribution to the construction of °ÄÃÅÁùºÏ²Ê¸ßÊÖ. Based on the European evaluation, the cost of °ÄÃÅÁùºÏ²Ê¸ßÊÖ construction for the seven Members had been evaluated in the past at approximately EUR 13 billion (if all the manufacturing was done in Europe). 

At the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council meeting in November 2016, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization proposed a complete updated project schedule through First Plasma (2025*) and on to Deuterium-Tritium Operation (2035). The overall project cost in line with the revised schedule added EUR 4 billion to the original estimate, a cost that was approved by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Members through their domestic budget processes. Following the challenges of the Covid pandemic, and taking into account additional technical setbacks announced in 2022, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization partners are now re-assessing the project’s schedule (and cost). This Updated Baseline will be reviewed by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Council in 2024.

For the other phases of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project the cost estimates have not changed. Operation of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ installation during its experimental lifetime (approximately 20 years) is estimated at 188 kIUA* per year. For the Deactivation (2037-2042) and Decommissioning phases, the costs have been established in euros at EUR 281 million and EUR 530 million respectively (EUR in 2001 values).

*The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Unit of Account was created as part of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Agreement to equitably allocate the value of in-kind hardware procurement to each Member. In 2023, 1 IUA = EUR 1,975.41

In a global context of rising oil and gas prices, decreased accessibility to low-cost fossil fuel sources, and an estimated three-fold increase in world energy demand by the end of this century, the energy question finds itself propelled to centre stage. How will it be possible to supply this new energy without adding to greenhouse gases?

Investing in renewables such as solar, wind and geothermal is important. Just like in fusion R&D ... with significant investment comes advancements in technology, and with advancements in technology comes a decrease in price. All calculations point to an increase in the importance of renewables in the decades to come.

The ideal future energy mix would hold a mixture of generation methods instead of a large reliance on one source. Fusion offers advantages that make it worth pursuing: carbon free, abundant energy that can operate in a baseload capacity, which is not easy for generation methods based on intermittent sources, such as wind or sun.

The fusion community doesn't see itself in competition with renewable forms of energy. Rather, in a world ever more dependent on energy, it is important to follow all of the promising options for our common future.

The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization manages its cost estimate and associated risk in the same way as any large project, using state-of-the-art software and industry-standard risk analysis. There is always a risk for a construction project managed over several years that certain "external" factors (labour, building materials) or "internal" factors (the complexity of increased interfaces in the design, design changes, nuclear safety authority requirements or inspections, manufacturing delays, technical setbacks, etc.) have an impact on the budget.

To track the risk of cost increase, each activity in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization cost estimate is assigned a level of uncertainty in accordance with a risk classification system. The values of the activities and their uncertainty classifications are then analyzed to predict confidence levels. These important tools allow management to identify and react to possible cost increases.

To compensate for the risk associated with the uncertainty in the cost estimate, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization at all times seeks cost savings to be able to offset potential cost increases. 

It took several years to achieve the licensing of °ÄÃÅÁùºÏ²Ê¸ßÊÖ as an "Installation Nucléaire de Base" under French law.

• The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization submitted a Preliminary Safety Report in March 2010 to the French Nuclear Safety Authority, which allowed the technical examination of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ safety files to begin;

• The French Environmental Authority, whose opinion on °ÄÃÅÁùºÏ²Ê¸ßÊÖ's nuclear licensing files is required in accordance with the EEC Directive 97/11/EC of 3 March 1997 on Environmental Assessments, delivered its opinion on 23 March 2011. The opinion was favourable and included several recommendations to be taken into account by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization;

• A Public Enquiry was held locally in the communes surrounding the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site from 15 June-4 August 2011. On 9 September 2011 the Public Enquiry Commission issued a favourable Advisory Opinion;

• The technical examination of the files by the Institute of Radioprotection and Nuclear Safety (IRSN), acting as the ASN's technical expert, began during the summer of 2010. In September 2011 the IRSN submitted a 300-page report—including 800 questions to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization—to a group of 30 experts appointed by ASN, the Groupe Permanent. The Groupe Permanent issued a favourable report at the end of 2011;

• The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization was informed in writing by the French safety authorities (ASN) on 20 June 2012 that, following an in-depth technical inspection, the operational conditions and the design of °ÄÃÅÁùºÏ²Ê¸ßÊÖ as described in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ safety files fulfilled expected safety requirements at this stage in the licensing process. Following this, the draft decree was communicated by the ASN to the French government for signature;

• On 10 November 2012, the French Prime Minister Jean-Marc Ayrault signed the that authorizes the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization as an "Installation Nucléaire de Base."

• In parallel, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization provided a nuclear safety stress report to the French safety authorities in late 2012, which had been requested from all nuclear power plants and research infrastructures in the country. The technical examination of the report was concluded in July 2013 by a standing session of the Groupe Permanent in France. This group of experts appointed by ASN communicated only one recommendation to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization: to study extreme climatic conditions such as tornado, hailstorms, etc. Taking into account the robustness of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ safety design, this stress test report did not lead to additional cost.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is the first nuclear installation in France to observe the stringent requirements of the 2006 French law on Nuclear Transparency and Security. It is also the first time in worldwide history that the safety characteristics of a fusion device have undergone the rigorous scrutiny of a Nuclear Regulator to obtain nuclear licensing. °ÄÃÅÁùºÏ²Ê¸ßÊÖ has achieved an important landmark in fusion history.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ was authorized in 2012 as a Basic Nuclear Installation in France (Installation Nucléaire de Base, INB) based on an in-depth technical examination of its design characteristics. Now, the project is going through similar regulatory steps to be authorized to assemble the machine.

In 2017 frequent exchanges took place with the French Nuclear Safety Authority (ASN) on the project's staged plan for assembly and operation between 2025 and 2035, an approach that was deemed compatible with the licensing procedure. An update of the preliminary safety report was undertaken to reflect all changes in the facility's design since the original report was submitted in 2010. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization also submitted a detailed safety file to respond to the ASN hold point for the authorization of machine assembly.

Two other important steps are part of the project's licensing roadmap: the request to French authorities (ASN) for an authorization to initiate First Plasma (and the subsequent hydrogen-helium plasmas of the non-nuclear phase), and a facility commissioning request in advance of the first use of tritium for the Deuterium-Tritium Operation phase. In both cases, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization will be required to update its Preliminary Safety Report and to prepare detailed safety files and other relevant safety-related reports.

See the updates in the next section.

Exchanges between the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization and ASN on °ÄÃÅÁùºÏ²Ê¸ßÊÖ's safety file for the authorization of machine assembly have been frequent since the file was accepted as admissible for further examination in May 2021. In January 2022, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization was informed by the ASN that the release of the machine assembly hold point—expected by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization in February 2022—would be delayed pending replies to ASN requests for further information. These exchanges have now been affected by the need for substantial repair on two types of machine components (vacuum vessel sector bevel joints and thermal shield cooling pipes).

Update October 2023. The redefinition of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Research Plan will imply both the update of the nuclear safety demonstration and the redefinition of the roadmap to licensing. Specific exchanges with the nuclear regulator in France, ASN, and its technical expert IRSN are underway. In the context of the development of a new °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project Baseline, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization is proposing to demonstrate nuclear safety with a stepwise approach to experiments. The proposed scenario foresees a robust Start of Research Operation followed by deuterium-tritium operation 1 (DT-1) with limited fluence, and finally a machine upgrade to enable a more extensive DT-2 phase with the target to complete all project goals including the Q=10 project specification. This approach would reduce risk by demonstrating full fusion power operation only after complete knowledge of system operation has been acquired in the earlier phases.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ is the first fusion device in the world to undergo nuclear licensing by state licensing authorities. °ÄÃÅÁùºÏ²Ê¸ßÊÖ is a precursor in this respect, and other fusion devices will benefit from the technical work accomplished by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization in every phase of licensing, from construction to operation to decommissioning. 

It's true that the nuclear fusion reaction in a tokamak is inherently safe. Achieving fusion requires very precise conditions. If a plasma is too cold or too hot, if there is too much fuel or not enough, if there are contaminants in the plasma, or if the magnetic fields are not optimal ... the reaction dies out.

However fusion processes do involve radioactive materials. °ÄÃÅÁùºÏ²Ê¸ßÊÖ, or the fusion power plants to follow, will have to manage the radiation produced through two mechanisms. One of the fusion fuels, tritium, is a radioactive form of hydrogen with a half-life of 12.3 years; the tritium absorbed by the infrastructure of the tokamak will give rise to some radioactivity. In addition, very fast neutrons produced by the fusion reaction will activate, over time, the material structures of the vessel.

The amount of tritium used during plasma pulses is very small—only a few grams at any one time. Careful procedures have been established for the handling and containment of tritium that have been well tried in other fusion facilities and through tritium applications in medicine and technology. An efficient static confinement barrier will be installed in the areas where tritium is handled and air pressure cascading in the buildings will inhibit the outward diffusion of tritium. Even if the containment were accidentally to be breached in the tokamak, the levels of radioactivity outside the °ÄÃÅÁùºÏ²Ê¸ßÊÖ enclosure would still be very low. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Preliminary Safety Report presents an analysis of risks that demonstrates that during normal operation, °ÄÃÅÁùºÏ²Ê¸ßÊÖ's radiological impact on the most exposed populations will be one thousand times less than natural background radiation. Even in "worst-case scenarios," such as fire in the Tritium Plant, evacuations or other countermeasures for the neighbouring populations would not be required.

Fusion reactors, unlike fission reactors, would produce no high activity/long life radioactive waste. The "burnt" fuel in a fusion reactor is helium, an inert gas. Activation produced in the material surfaces by the fast neutrons will produce waste that is classified as very low, low, or medium activity waste. All waste materials will be treated, packaged, and stored on site. Because the half-life of most radioisotopes contained in this waste is lower than ten years, within 100 years the radioactivity of the materials will have diminished in such a significant way that the materials can be recycled for use in other fusion plants, for example. This timetable of 100 years could possibly be reduced for future devices through the continued development of "low activation" materials, which is an important part of fusion research and development today.

The activation or contamination of in-vessel components, the vacuum vessel, the fuel circuit, the cooling system, the maintenance equipment, or buildings will produce an estimated 30,000 tons of decommissioning waste that will be removed from the °ÄÃÅÁùºÏ²Ê¸ßÊÖ facility and processed.

The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization was licensed as a nuclear operator in France in November 2012, following the in-depth technical inspection of its safety files. Because it is the first nuclear installation to be licensed in France since 2006, °ÄÃÅÁùºÏ²Ê¸ßÊÖ is the first one to observe the 2006 French law on Nuclear Transparency and Security and the first fusion device in history to have its safety characteristics undergo the rigorous scrutiny of a Nuclear Regulator to obtain nuclear licensing.

No! What happened in the fission reactors in northeastern Japan following the severe earthquake and subsequent tsunami in 2011 could not happen at °ÄÃÅÁùºÏ²Ê¸ßÊÖ. This is due to the fundamentally different physics and technologies used in fission and fusion reactors.

In a fusion reactor, there will only be a very limited amount of fuel inside the reactor at any time. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ fuel is a gaseous mixture, a plasma of deuterium and tritium. In order to maintain the fusion reaction we rely on the continuous supply of fuel. If the fuel supply is interrupted for any reason, the fusion process stops immediately. There is absolutely no danger of a nuclear meltdown or a runaway reaction.

Moreover, loss of the cooling function due to an earthquake would not affect the confinement barrier at all. Even in the case of the total failure of the water cooling system, °ÄÃÅÁùºÏ²Ê¸ßÊÖ's confinement barriers will remain intact. The temperatures of the vacuum vessel that provides the confinement barrier would under no circumstances reach the melting temperatures of the materials.

The maximum amount of tritium in the facility will be set by the French safety authorities, and will not exceed 4 kg. The actual amount in °ÄÃÅÁùºÏ²Ê¸ßÊÖ at any time will be determined by operational needs based on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Research Plan.

Tritium will be stored as metal hydride (i.e., chemically bound to a metal) in dedicated vessels, called metal hydride beds. Metal hydride beds are very efficient for tritium collection and provide a safe way of storing tritium. Only the amounts necessary for operation of the fuel cycle will be liberated from the beds. Their confinement performance will follow a very strict qualification program; losses from the storage beds will only be due to the natural radioactive decay of tritium (half the tritium decays into inert helium every 12.3 years).

°ÄÃÅÁùºÏ²Ê¸ßÊÖ has implemented not only state-of-the-art confinement methodologies but also above-and-beyond technologies to provide removal and recovery of tritium for the very unlikely event of tritium spilled into rooms. Control of stock is maintained is through a tritium tracking procedure and regular inventory measurements. Security measures will be in place to protect the tritium in stock.

The °ÄÃÅÁùºÏ²Ê¸ßÊÖ facility is designed to resist an earthquake of amplitude x40 and energy x250 higher than any earthquake for which we have historical or geological references in the area of Saint Paul-lez-Durance, France. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Tokamak Building will be made of specially reinforced concrete, and will rest upon bearing pads, or pillars, that are designed to withstand earthquakes (this technology is used to protect other civil engineering structures such as electrical power plants from the risk of earthquake). The risk of flooding, too, has been taken into account in °ÄÃÅÁùºÏ²Ê¸ßÊÖ's design and Preliminary Safety Report. In the most extreme hypothetical situation—that of a cascade of dam failures north of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site—more than 30 metres remains between the maximum height of the water and the first basemat of the nuclear buildings.

Following the natural disaster in Japan in March 2011, and the resulting tsunami and nuclear accident at Fukushima Daiichi, the French government requested that the French Nuclear Safety Authority (ASN) carry out complementary safety assessments. The decision was made to assess not only nuclear power plants, as requested at the European level, but also research infrastructures in order to examine the resistance of a facility in the face of a set of extreme situations leading to the sequential loss of lines of defence, such as very severe flooding, a severe earthquake beyond that postulated in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ safety case, or a combination of both.

The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization provided a nuclear safety stress report to the French safety authorities on 15 September 2012. The technical examination of the report was concluded in July 2013 by a standing session of the Groupe Permanent in France. This group of experts appointed by ASN communicated only one recommendation to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization: to study extreme climatic conditions such as tornado, hailstorms, etc.

In a tokamak fusion device, the quantity of fuel present in the vessel at any one time is sufficient for a few-seconds burn only. It is difficult to reach and maintain the precise conditions necessary for fusion; any disruption in these conditions and the plasma cools within seconds and the reaction stops, much in the same way that a gas burner is extinguished when the fuel tap is turned off. The fusion process is inherently safe; there is no danger of run-away reaction or explosion.
Although 100 million degrees Celsius is an extremely high temperature, the density of the plasma (atoms per cubic metre) is very low—about one million times less than air—and the total energy in the plasma is not very great. The very rapid release of the energy could cause superficial damage to some plasma-facing components (i.e., surface melting) but would not be sufficient to produce structural damage.
There are no fissile materials like plutonium or highly enriched uranium in a fusion reactor that could be exploited to make nuclear weapons. The use of tritium in °ÄÃÅÁùºÏ²Ê¸ßÊÖ will not open a new way for the production of mass destruction weapons. Tritium is already used commercially, in small quantities, for medical diagnostics and sign illumination.
The safety analyses presented in the Preliminary Safety Report of °ÄÃÅÁùºÏ²Ê¸ßÊÖ take the complete surroundings into account, including all installations, either nuclear or conventional, that could have an influence on °ÄÃÅÁùºÏ²Ê¸ßÊÖ. These studies show that °ÄÃÅÁùºÏ²Ê¸ßÊÖ safety will not be impacted by accidents occurring in surrounding installations.
The °ÄÃÅÁùºÏ²Ê¸ßÊÖ design takes into account external hazards in accordance with French regulation and practices. The Preliminary Safety Report submitted by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization to the French licensing authorities includes an in-depth analysis of external hazards, including man-made hazards. This includes the consequences of events such as aircraft crashes, and part of the Preliminary Safety Report is dedicated to providing evidence of °ÄÃÅÁùºÏ²Ê¸ßÊÖ safety even against malevolent acts.
It's true that continued cooling is required in a fission reactor because, even after shutdown, there is a substantial decay heat to be eliminated that is produced by the fission decay of the tons of nuclear fuel present in the vessel.   In °ÄÃÅÁùºÏ²Ê¸ßÊÖ or in future fusion power plants, this kind of scenario is impossible. The thermal power induced in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ vacuum vessel will be low. Even if no active cooling of the vacuum vessel is provided, as in the case of total failure of the cooling system, the resulting temperature would not threaten the integrity of the vacuum vessel.

At °ÄÃÅÁùºÏ²Ê¸ßÊÖ, an integrated safety management system will be put into place to address all potential hazards in compliance with industrial safety regulations. Potential hazards will be addressed specifically by department, and appropriate safety measures put into place. Non-radiological hazards taken into consideration at °ÄÃÅÁùºÏ²Ê¸ßÊÖ include fire, exposure to magnetic and electromagnetic fields, exposure to chemicals or cryogenic fluids, and high voltages. To protect workers, access to the Tokamak Building will be strictly forbidden during operation.

Only a small fraction of the tritium in the tokamak is actually consumed during a plasma burn. Tritium will be separated from the exhaust gases pumped from the tokamak vessel, purified, and stored for reuse. The effectiveness of tritium removal from the room atmosphere and from the liquid effluents and recovery during tritium plasma operation is independent of the fusion performance of the tokamak. The design is based on a scenario in which no tritium is burned but it is all returned from the tokamak vessel to the recovery system.   Many provisions are implemented into the design to avoid losses of tritium. An efficient static confinement barrier will be installed in the areas where tritium is handled and air pressure cascading in the buildings will inhibit the outward diffusion of tritium. The static and dynamic confinement systems as well as radiological and environmental monitoring will be available for several years before tritium is put in the machine (i.e., from the beginning of the deuterium-deuterium phase of operation). Even the small amounts of tritium generated during deuterium-deuterium operation will be removed and eventually recovered through fuel cycle processing systems.
The °ÄÃÅÁùºÏ²Ê¸ßÊÖ design is such that, even if the containment were accidentally to be breached in the tokamak, the levels of radioactivity outside the °ÄÃÅÁùºÏ²Ê¸ßÊÖ enclosure would still be very low. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Preliminary Safety Report presents an analysis of risks and events that may cause accidents in the facility.  During normal operation, °ÄÃÅÁùºÏ²Ê¸ßÊÖ's radiological impact on the most exposed populations will be one thousand times less than natural background radiation and in "worst-case scenarios" such as fire in the tritium plant, evacuations or other countermeasures for the neighbouring populations would not be required.

First, let's take a foray into the world of neutrons. Lone—or "free"—neutrons are created naturally by cosmic rays interacting with the upper layers of the atmosphere. At their initial speed, it's only a short trip to the Earth's surface. But on the way they have every chance of encountering the nitrogen, oxygen or carbon particles present in the air, getting absorbed and forming an isotope ... or bouncing off the surface of the particle nucleus and losing energy in the process.

As a result, only a few of these "space" neutrons ever reach the Earth's surface—approximately 100-300 neutrons per second per square metre. If they have retained enough energy, they may be absorbed by elements present in the soil such as iron, silicon, potassium, etc. Or they'll die a quick death, decaying into a proton, an electron and a neutrino.

Neutrons will also be generated by the fusion reaction inside of °ÄÃÅÁùºÏ²Ê¸ßÊÖ. At full power, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ machine will generate some one hundred billion billions of highly energetic neutrons per second. Instead of the thin air of outer space, however, fusion neutrons will face a succession of daunting physical obstacles, some exceptionally dense.

Thick shielding blankets; high-strength copper and stainless steel in the first wall of the vacuum vessel; ultra-dense neutron-hungry borated concrete in the bioshield—these materials will contribute to absorbing the neutron flux from the fusion reaction and keep radiation from escaping to the environment.

But given the proportion of void in even the densest materials, won't some neutrons pass all the obstacles unscathed? Yes, but not enough to worry about however—the survivors will be so few that they will be indistinguishable from the natural background "noise" of neutrons.

Physicists have been exploring the properties of plasmas within tokamak devices since the 1960s. It is well known that beyond certain operational boundary conditions—for example, when plasma current, pressure or density rises too high for a given magnetic field—the plasma can become unstable.

A disruption is an instability that may develop within the tokamak plasma. Disruptions lead to the degradation or loss of the magnetic confinement of the plasma, and because of the high amount of energy contained within the plasma, the loss of confinement during a disruption can cause a significant thermal loading of in-vessel components together with high mechanical strains on the in-vessel components, the vacuum vessel and the coils in the tokamak.

In some cases, because of the large electric fields created during the disruptions, a relativistic electron beam (containing "runaway electrons") forms that can penetrate several millimetres into the in-vessel components when it is eventually lost from the plasma.

 

Unless mitigating action is taken, plasma-facing components can suffer local damage due to the thermal loads and to the deposition of runaway electrons during disruptions. In addition, in extreme cases, the mechanical strains on the components during disruptions may cause some deformation.

Disruptions are not triggered randomly; they only occur when well-defined limits are exceeded. Disruptions have been observed, avoided and mitigated in most operating tokamaks. One of °ÄÃÅÁùºÏ²Ê¸ßÊÖ's objectives is to perfect a stable operating scenario through experimentation so that disruptions become a relatively rare event. During the first years of operation, °ÄÃÅÁùºÏ²Ê¸ßÊÖ operators will most likely deliberately provoke disruptive events. Their aim will be to analyze, and to learn to control, these events at reduced plasma parameters and low plasma energy so that disruptions cannot cause damage to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ components in experiments at the highest plasma current and energy. 

By "pushing" the machine toward disruptions at modest plasma parameters, °ÄÃÅÁùºÏ²Ê¸ßÊÖ operators will find its stability boundaries. Once these stability limits have been identified, there is no reason for plasmas in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Tokamak to become disruptive spontaneously as the plasma current and plasma energy is increased, provided that this is done within the stability region identified.

There is abundant literature on the subject of disruptions (see, in particular, Nuclear Fusion) and on the operational strategies to avoid disruptions and to mitigate their effects when they cannot be avoided.

Disruptions are an integral part of the official (and public) physics basis for °ÄÃÅÁùºÏ²Ê¸ßÊÖ, which has been extensively refereed by the scientific community ("°ÄÃÅÁùºÏ²Ê¸ßÊÖ Physics Basis," Nuclear Fusion, 47; 2007 complemented the initial 1999 report). Disruptions represent an active field of research in the fusion community in order to perfect the avoidance and mitigation schemes being developed for °ÄÃÅÁùºÏ²Ê¸ßÊÖ.

The European tokamak JET and the French tokamak Tore Supra, as well as many others in the world, have been operated in a completely safe and satisfactory manner since 1983 and 1988 respectively. When exploring new plasma regimes, or during dedicated experiments to study disruptions and their mitigation, disruptions can occur several times a day in these two machines and others, but they have never led to the destruction or rupture of their vacuum vessels.

Because disruptions are expected in °ÄÃÅÁùºÏ²Ê¸ßÊÖ, they have been planned for. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ vacuum vessel and in-vessel components have been designed to withstand the forces produced by about 3,000 disruptions at full plasma performance over the course of their lifetime. °ÄÃÅÁùºÏ²Ê¸ßÊÖ's resistance to disruptions is based on scaling laws ("engineering laws") that have determined the values chosen for °ÄÃÅÁùºÏ²Ê¸ßÊÖ; these values have been validated by experiments on other tokamaks.

It is important to understand that disruptions are not a safety-class issue for °ÄÃÅÁùºÏ²Ê¸ßÊÖ: there is absolutely no risk for the integrity of the vacuum vessel. But as the high energy loads during disruptions can, over time, damage the surface of plasma-facing components such as divertor targets and first wall panels, these components may need—and have been designed—to be replaced. This takes time and reduces the availability of °ÄÃÅÁùºÏ²Ê¸ßÊÖ for experiments. It is therefore important to develop disruption mitigation techniques that reduce the forces and the energy loads on °ÄÃÅÁùºÏ²Ê¸ßÊÖ's components so that the time between interventions to replace these components is as long as possible, thereby optimizing the scientific exploitation of °ÄÃÅÁùºÏ²Ê¸ßÊÖ.  

During the progressive commissioning of °ÄÃÅÁùºÏ²Ê¸ßÊÖ, the machine will be tested with plasma currents and plasma energies lower than the nominal values required for fusion energy production. In this way, the potential degradation of °ÄÃÅÁùºÏ²Ê¸ßÊÖ's components by disruptions during this initial learning phase will be minimized. We will begin with low current and low-energy plasmas to learn how to avoid and mitigate the effects of disruptions on °ÄÃÅÁùºÏ²Ê¸ßÊÖ before moving on to more advanced operational scenarios with higher currents and higher energies (thus larger forces and energy loads on components).

The °ÄÃÅÁùºÏ²Ê¸ßÊÖ strategy is not radically different from that already followed in the operation of the largest existing tokamak JET, which achieved plasma currents of 6-7 MA (as compared to the 15 MA nominal plasma current planned in °ÄÃÅÁùºÏ²Ê¸ßÊÖ).

In summary, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ engineering design allows for disruptions to occur in approximately 10 percent of plasma pulses. The early, low-energy/low-plasma-current phase of °ÄÃÅÁùºÏ²Ê¸ßÊÖ will permit physicists to characterize disruptions on °ÄÃÅÁùºÏ²Ê¸ßÊÖ without risks to the machine. Disruption mitigation is one of the specific scientific missions of °ÄÃÅÁùºÏ²Ê¸ßÊÖ, with direct relevance to the future development of fusion power plants based on the tokamak concept.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ's Disruption Mitigation System (DMS) is currently in its design phase. In determining the best method, or combination of methods, for disruption mitigation, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization is taking into account performance, reliability, flexibility, and cost.

Two promising methods are on the table that will be further refined in the coming months and years for °ÄÃÅÁùºÏ²Ê¸ßÊÖ scenarios. Following years of development work, shattered pellet injection—in which massive amounts (up to 500 g) of particles are introduced into the plasma within 10 milliseconds—has been chosen as the baseline technique to disperse the energy of a disruption before it can concentrate its load on the wall of the containment vessel. Develpment work on a second approach, massive gas injection, will continue as part of risk mitigation.

An R&D program in disruption mitigation for °ÄÃÅÁùºÏ²Ê¸ßÊÖ is currently underway. Experiments run on the ASDEX Upgrade (Germany), KSTAR, Tore Supra (France), DIII-D (US), and JET (EU), to cite a few of the tokamaks involved in this research, are contributing to the refinement of predictions for disruption mitigation in °ÄÃÅÁùºÏ²Ê¸ßÊÖ. The ever-increasing capability for numerical simulation of disruptions is also being applied in the elaboration of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ disruption mitigation strategy.

The Disruption Mitigation System in °ÄÃÅÁùºÏ²Ê¸ßÊÖ will function automatically, triggered as disruptions occur during plasma pulses by dedicated sensors and algorithms that can evaluate the likelihood of an impending disruption. With at least 10 pulses planned per day during operational phases, and disruptions expected in approximately 10 percent of these, it is accurate to say that the Disruption Mitigation System will operate routinely—probably daily—during operation, at least during the initial phases as the °ÄÃÅÁùºÏ²Ê¸ßÊÖ operational scenarios are being developed.

Fusion reactors, unlike fission reactors, produce no high activity/long-lived radioactive waste. The "burnt" fuel in a fusion reactor is helium, an inert gas. Activation produced in the material surfaces by the fast neutrons will produce waste that is classified as very low, low, or medium activity waste. All waste materials will be treated, packaged, and stored on site. Because the half-life of most radioisotopes contained in this waste is lower than ten years, within 100 years the radioactivity of the materials will have diminished in such a significant way that the materials can be recycled for use (in other fusion plants, for example). This timetable of 100 years could possibly be reduced for future devices through the continued development of "low activation" materials, which is an important part of fusion research and development today.

The activation or contamination of in-vessel components, the vacuum vessel, the fuel circuit, the cooling system, the maintenance equipment, or buildings will produce an estimated 30,000 tonnes of decommissioning waste that will be removed from the °ÄÃÅÁùºÏ²Ê¸ßÊÖ scientific facility and processed.

°ÄÃÅÁùºÏ²Ê¸ßÊÖ, as operator, will bear the financial responsibility for the temporary and final storage of operational radioactive waste. Host State France will be in charge of the dismantling phase and the management of the waste resulting from this dismantling; the cost for these activities will be provisioned by °ÄÃÅÁùºÏ²Ê¸ßÊÖ during the operation phase and shared by the Members. France will also be responsible for providing temporary storage for part of the operational waste, pending its final disposal; this will be financed through °ÄÃÅÁùºÏ²Ê¸ßÊÖ operation cost.

Electrical supply to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site will be assured by an existing network that feeds the Tore Supra Tokamak—part of the adjacent CEA Cadarache research facility. The French electricity provider RTE completed a 4-hectare switchyard on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ platform and the connection to the main network in June 2012. Operating the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Tokamak will require from 120 MW to up to 620 MW of electricity for peak periods of 30 seconds. No disruption to local users is expected.

Concerning water supply, approximately 3 million cubic metres of water will be necessary per year during the operational phase of °ÄÃÅÁùºÏ²Ê¸ßÊÖ. This water will be supplied by the nearby Canal de Provence, and transported by gravity through underground tunnels to the fusion installation. The volume of water needed for °ÄÃÅÁùºÏ²Ê¸ßÊÖ represents only 1 percent of the total water transported by the Canal de Provence. The combined effect of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ installation and the adjacent CEA facilities remains below 5 percent of the total volume of water transported by the Canal de Provence.

To minimize the risk of congestion in the vicinity of both the CEA-Cadarache and °ÄÃÅÁùºÏ²Ê¸ßÊÖ sites, the following measures will be important: strengthening the public transport network, carpooling, and staggering the arrival and departure times for °ÄÃÅÁùºÏ²Ê¸ßÊÖ site workers. Infrastructure modifications are also underway at the highway exit to facilitate traffic.

No, it's not. The workers on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ construction site are protected by French law, which provides that all companies operating in France, whatever their "nationality," are subjected to French labour regulations and more specifically the regulatory minimum salary.

In addition, in accordance with the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Agreement the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization observes applicable French laws and regulations concerning public and occupational health and safety (see the next question for more information on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization's legal status). On-site inspections by the competent authorities are regularly performed on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ worksite, just as they are for all large construction projects in France. 

Concerning the housing of workers who do not live locally, the construction companies operating on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site have a contractual obligation to provide it. The quality of all housing solutions must strictly comply with French regulations.

As explained in the preceding questions, French law protects the on-site construction workers. Irrespective of the nationality of the company that has been awarded a contract or the nationality of the workers, French labour regulations and collective agreements per branch ("conventions collectives") apply. In 2011, the French government drafted guidelines detailing the full set of obligations and responsibilities of a foreign construction company participating in the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project including, for example, pay scales per branch and per level of qualification. The application of these rules is strictly controlled by the French authorities. All subcontractors working on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site, whether for the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization or one of the Domestic Agencies, have a copy of these guidelines.

Staff employed directly by the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization (approximately 1,200 people) is hired under the specific regime of an international organization and benefits from the status of international civil servant. Other employees (contractors, temporary agents ...) who work in the office buildings fall under the regime of French work codes and regulations.

​As Host Member to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project, Europe has the responsibility to build nearly all of the 39 buildings and technical areas of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ platform. The Domestic Agency for Europe (Fusion for Energy) has thus been charged with managing the tender offers for the building projects entrusted to Europe and awarding the related contracts (principally to European companies).

Fusion for Energy has put into place a rigorous qualification process for companies. Companies must prove:

  • conformity with laws and regulations and contractual requirements at an administrative level (up-to-date insurance policies and social contributions);
  • conformity with laws and regulations and contractual requirements in terms of security (companies must submit valid security and occupational health policies);
  • technical conformity (the contractor must prove that it has the technical capacity to carry out the work demanded).

Meeting these conditions is a requirement for any company hoping to be awarded a construction contract with Fusion for Energy. Fusion for Energy can exercise its right of audit at any time during the execution of contractual works.

According to the European Domestic Agency construction contracts, a maximum of two tiers of subcontracting is permitted. As a result, no part of the contracted works may be subcontracted to a third tier unless otherwise approved by Fusion for Energy. Compliance with this clause is closely monitored and up to now this requirement has been complied with strictly.

The construction of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ facility is estimated at 18 million person hours. The number of workers involved in site construction peaked in 2017-2018 at approximately 2,000 people according to the European Domestic Agency, which is responsible for the construction of all buildings and technical infrastructure. 

In parallel, a large workforce is now contributing to machine and plant assembly and installation operations. An estimated 5,000 people are regularly present on the worksite, including management, engineering and supervisory teams from the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization, the European Domestic Agency, and their contractors. (Another 1,600 people are directly attached to the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization as staff, °ÄÃÅÁùºÏ²Ê¸ßÊÖ Project Associates or interim personnel.)

According to recent statistics (October 2022), some 90 countries are represented on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ worksite. Europe is heavily represented and, within Europe, France as host (3,885 people). Italians come second (421), followed by Spaniards (335), Indians (254), Chinese (214), Portuguese (165) and Romanians (119). (See a full breakdown in this recent article from the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Newsline.) In the coming years, personnel will also be required for test activities, preservation and maintenance, and systems operations.

Certainly not. As stated above, contractors and subcontractors on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site must comply with French law. All workers on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site are paid at least the French minimum wage. In case of infringement, the incriminated company would immediately be denied approval. For part time work, workers are paid a pro-rata percentage of the legal full-time wage, in accordance with the number of hours worked.

The modalities of collaboration between the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization and the French labour inspectorate were defined in the Headquarters Agreement signed between the French government and the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization, as well as in an additional protocol relating to on-site labour inspections concerning occupational health and safety. The French labour inspectorate can carry out unplanned inspections, as foreseen in Article 3 of the Headquarters Agreement and in the annual program of inspections. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization has provided the labour inspectorate with a permanent access badge.

In addition, on 1 February 2013 the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization signed a partnership arrangement with the French social security agency URSSAF PACA. By doing so, the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization has committed to facilitating that agency's mission of prevention—through information, education and inspection—of illegal labour practices on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ construction site. URSSAF PACA organizes information/training sessions on labour laws and regulations for all companies involved in °ÄÃÅÁùºÏ²Ê¸ßÊÖ construction and inspections will be carried out on a regular basis.

The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization is working in full collaboration with URSSAF in line with the access rules applicable on the °ÄÃÅÁùºÏ²Ê¸ßÊÖ site. The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization is informed in advance of planned URSSAF inspections to prepare the access but this does not mean that contractors are informed. It is in the interest of the °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization and of the project as a whole that the French authorities implement the necessary on-site control of working conditions.

European Domestic Agency construction contracts are based on FIDIC conditions—an international standards organization for the construction industry. Contractors are entitled to an advance payment in the range of 10% of the contract price. A schedule of payments is attached to the contract which specifies the further instalments to be paid to the contractor and the conditions for payment.

Each contractor submits its estimates monthly to the Engineer in charge of the management of the construction site. This estimate presents the detail of the amounts considered owed and supporting documents proving work progress. The Engineer certifies the amounts owed in relation to work performed and issues a payment certificate that is used by the contractor to submit its invoice to the European Domestic Agency (Fusion for Energy). The Engineer can withhold the payment certificate in a few cases only, each related to the breach of the contractor's specified obligations under the contract.

According to the terms of the contract, Fusion for Energy pays the stated amount after receipt of the contractor's invoice (usually within 45 days). In the event of delayed payment, the contractor is entitled to late payment interest. Furthermore, Fusion for Energy work contracts specify that the contractor shall be wholly responsible for paying any amounts properly due (and undisputed) to its subcontractors.