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ITER NEWSLINE 255
The European Fusion Development Agreement (EFDA) has published a roadmap which outlines how to supply fusion electricity to the grid by 2050. The roadmap to the realization of fusion energy breaks the quest for fusion energy down into eight missions. For each mission, it reviews the current status of research, identifies open issues, proposes a research and development program and estimates the required resources. It points out the needs to intensify industrial involvement and to seek all opportunities for collaboration outside Europe.
The goal of fusion research is to make the energy of the stars available on Earth by fusing hydrogen nuclei. Fusion energy is nearly unlimited as it draws on the abundant raw materials deuterium and lithium. It does not produce greenhouse gases or long-lived radioactive waste. It is intrinsically safe, as chain reactions are impossible.
So far, fusion scientists have succeeded in generating fusion power, but the required energy input was greater than the output. The international experiment ITER, which starts operating in 2020, will be the first device to produce a net surplus of fusion power, namely 500 megawatts from a 50 megawatt input.
Europe holds a leading position in fusion research and hosts ITER. The fact that the ITER Project is funded and run by six other nations besides Europe reflects the growing expectations on fusion energy. China, for instance, is launching an aggressive program aimed at fusion electricity well before 2050. "Europe can keep pace only if it focuses its effort and pursues a pragmatic approach to fusion energy" states Francesco Romanelli, EFDA Leader.
Focusing on the research and engineering activities needed to achieve fusion electricity, the roadmap shows that these can be carried out within a reasonable budget. The amount of resources proposed are of the same level as those originally recommended for the seventh European Research Framework Programme — outside the European investment in the ITER construction.
The roadmap covers three periods: The upcoming European Research Framework Programme, Horizon 2020, the years 2021-2030 and the time between 2031 and 2050.
ITER is the key facility of the roadmap as it is expected to achieve most of the important milestones on the path to fusion power. Thus, the vast majority of resources proposed for Horizon 2020 are dedicated to ITER and its accompanying experiments. The second period is focused on maximizing ITER exploitation and on preparing the construction of a demonstration power plant DEMO, which will for the first time supply fusion electricity to the grid. Building and operating DEMO is the subject of the last roadmap phase.
In the course of the roadmap implementation, the fusion program will move from being laboratory-based and science-driven towards an industry- and technology-driven venture. ITER construction already generates a turnover of about EUR 6 billion. The design, construction and operation of DEMO requires full involvement of industry to ensure that, after a successful DEMO operation, industry can take responsibility for commercial fusion power.
The roadmap document can be dowloaded here.
ITER's economic impact on neighbouring villages was felt with a certain intensity, on Wednesday 23 January, as representatives from France's electricity carrier RTE presented Mayor Roger Pizot of Saint-Paul-lez-Durance with a EUR 900,000 check.
The money was intended as "compensation" for the implantation, within city limits, of the 400kV power line that feeds the ITER switchyard. As required by French law, the compensation must represent 10 percent of the cost of the power line works (EUR 9 million)—quite a sum for a village whose annual budget does not exceed EUR 5 million.
However Mayor Pizot considered that, as neighbouring Vinon-sur-Verdon had also been impacted by the power line (at least visually), it was only fair to split the sum with his colleague Claude Cheilan, the Mayor of Vinon.
In both villages, the money was soundly invested. In Saint-Paul (pop. 992), the village council decided to modernize the village's street lighting in order to reduce the municipality's electricity bill, renew the equipment of Saint-Paul's public park, and also attribute EUR 50,000 to the local association that is in the process of renovating the 16th century pigeon tower located near the Château de Cadarache. The village of Vinon (pop. 4,100) will use the compensation money to create a much-needed pedestrian and bicycle passageway that will run along the present bridge over the Verdon River.
The official ceremony held last week in Saint-Paul's town hall was also the occasion for the sous-préfet of Aix-en-Provence, representing the French government, to insist on the importance of the ITER-induced economic benefits for the region. "Since the beginning of works on the ITER site," Yves Lucchesi reminded the audience, "more than EUR 620 million in contracts have been attributed to companies based in the Provence-Alpes-Côte d'Azur region."
Have you ever wanted to visualize what happens inside of a tokamak?
In a spectacular new video on ITER operation produced by the National Center of Computational Sciences (located at Oak Ridge National Laboratory, US), you can follow high-velocity deuterium particles as they are injected into the ITER plasma.
Against a backdrop of symphonic music played by the Czech National Symphony Orchestra, the particle density in the plasma begins to build, the injected particles start to collide with their lower-energy cousins, and their energy is transferred, heating the plasma and driving the plasma current. The conditions are ripe for fusion reactions, and a small Sun is created in the centre of the machine.
Produced from supercomputer simulations, the video will take you behind the walls and past the complex supporting systems for ITER, into the very heart of the fusion reaction.
Watch the video here.
"Fusion Energy Production by Deuterium Particle Injection" was funded in part by the US Department of Energy, Oak Ridge National Laboratory, and the National Center of Computational Sciences. (Visualization by Jamison Daniel.)
As the flagship program of the international fusion community and a new kind of international collaboration in science, the ITER Project has to demonstrate transparency and exemplarity in all of its activities. For questions of labour regulations on the ITER worksite—where some 3,000 workers will be active during the height of construction activities—the ITER Organization is working closely with the French authorities to protect against illegal labour practices among the contractors and sub-contractors.
In signing a partnership arrangement with the French social security agency URSSAF PACA on 1 February 2013, the ITER Organization has committed to facilitating that agency's mission of prevention—through information, education and inspection—of illegal labour practices on the ITER worksite.
The ITER Organization was established as a public international organization in France, with the benefit of privileges and immunities that ensure its independence. However, the ITER Agreement (Article 14) stipulates that the Organization shall observe Host state laws and regulations in a certain number of cases, including public and occupational health and safety, nuclear safety, and environmental protection.
As a result, the French labour code applies to all contractors and sub-contractors present on the ITER worksite, irrespective of their country of origin, or that of their workers.
According to the conditions of the convention signed last week, URSSAF PACA will organize information/training sessions on labour laws and regulations for all companies involved in ITER construction. Inspections will be carried out on a regular basis, and a report made to the ITER Organization in the case of violation of French laws by contractors or sub-contractors.
The periodicity of URSSAF visits and information sessions, inspection and follow-up procedures, and access formalities are all specified in the document.
The ITER Organization-URSSAF PACA convention is based on a similar partnership arrangement that was in effect from 2007 to 2010 between Agence Iter France (charged with site preparatory works) and URSSAF PACA. With the transfer of the ITER site from Agence Iter France to the ITER Organization in 2010, this convention had become null and void.
"The prevention of illegal labour practices and of their human, social and economic consequences is our common preoccupation," said ITER Director-General during the signature ceremony. "ITER was launched 25 years ago as a scientific program to benefit the whole of humanity. It follows that in our daily practices we must be irreproachable."
Dominique Clement, URSSAF PACA director, underlined the "exemplary" character of the collaboration undertaken with the ITER Organization: "The ITER Organization has sent out a strong signal today, one that will serve as an example for all of the large building projects in the region."
Muriel Gauthier, representing Regional Prefect Hugues Parant, reminded the audience that—in a context of generalized economic difficulties—the prevention of illegal labour practices is a priority for the French government.
The convention signed last week will be tacitly renewed every year.
After an intensive effort to improve the capability of ITER's central solenoid conductor, the ITER Organization has concluded that a technically reliable and economically viable solution has been found. This successful result was obtained through a concerted collaborative effort on the part of the ITER Organization, especially with the Domestic Agencies of Japan and the US, and the international superconductivity research community. The key element of the solution was designing the conductor using a "short twist pitch." The Japanese strands using this technology confirmed the excellent results obtained during a preceding R&D phase and even enabled the qualification of two additional Japanese strand suppliers for the central solenoid conductor production.
The ITER central solenoid is one of the most challenging superconducting magnets ever designed. It is made up of a stack of six, independently powered coil modules. The coil stack has a total height of 13.5 metres and an outer diameter of 4.1 metres. One particularity of the central solenoid is that it will be used to inductively drive 30,000 plasma pulses of 15 MA with a burn duration of 400 s.
During their life time, the central solenoid coil modules will have to sustain severe and repeated electromagnetic cycles to high current and field conditions. The most solicited modules are the middle modules in the stack, which will experience up to 60,000 cycles to a maximum peak field of 13 T. This is way beyond anything a large superconducting magnet of this kind has ever experienced. Another challenge is that the ITER central solenoid is a joint in-kind procurement: the US Domestic Agency is responsible for the central solenoid coil stack, while the Japanese Domestic Agency is responsible for the central solenoid conductor.
Like all other ITER magnets, the central solenoid relies on a Cable-in-Conduit Conductor (CICC) made up of a rope-type cable that is inserted into a stainless steel conduit where a forced flow of supercritical helium circulates. For the central solenoid, the cable relies on 576 superconducting strands mixed with 288 pure copper strands and assembled in five stages around a central cooling spiral. The conduit has a circle-in-square shape and relies on a special high manganese austenitic steel with excellent low fatigue crack growth rate properties at cryogenic temperatures. To achieve the required high field, the superconducting strands are made out of a special alloy made of niobium and tin (Nb3Sn), a material with good current transport properties but that, once formed, becomes brittle and strain-sensitive and which must be handled with care.
The first performance qualification samples of ITER central solenoid conductors that were tested in the SULTAN facility in Villigen, Switzerland, exhibited excessive degradation as a function of electromagnetic and thermal cycling and did not meet the performance criteria under the SULTAN configuration, which is defined for stable operation of the central solenoid during the life cycle of the ITER machine.
Following these unexpected results, the ITER Organization in early 2010 launched a comprehensive R&D program, with the support of the US ITER Domestic Agency and Oxford Superconducting Technology (US), to investigate alternative conductor configurations that could potentially achieve more stable performances. This EUR 1.1 million program was successfully completed in May 2012 and a clear solution emerged: among the four variants that were tested, the conductor with the so-called "short twist pitch" configuration behaved as required.
In the "short-twist pitch" set-up, the strands are mechanically better supported and have little room for deleterious bending resulting in almost non-existing degradation as a function of electromagnetic and thermal cycling. The test results even show a slight increase in performance, likely due to compressive strain relaxations that may not be representative of in-coil operation.
The results of the R&D demonstrated that cycling degradation was not inherent to Nb3Sn CICCs and that a technical and economically viable solution could be found to this challenging issue. It remained for the Japanese manufacturers to demonstrate that the short twist pitch configuration could result in the same performance on their strands. In order to do so, the Japanese Atomic Energy Agency (JAEA) prepared a number of samples that were meant to match or even surpass the performances of the ITER Organization samples. The first of these samples (referred to as CSJA3) was tested in November-December 2012. The tests in SULTAN confirmed the excellent results obtained with the short twist pitch sequence, which demonstrated the best performance. It also enabled the qualification of two additional Japanese strand suppliers for central solenoid conductor production.
The story of central solenoid conductor development is a good example of how scientific collaboration across many borders can lead to solutions for even the most extraordinary challenges of building the ITER machine—a device that pushes most technologies to their limits and calls for innovative solutions.
Special thanks to Arnaud Devred, ITER Superconductor Section Leader, for his contribution to this article.
The worldwide plasma physics community mourns Prof. Dr. Padma Kant Shukla who died from a heart attack in New Delhi, India on 26 January 2013. Shortly before, Prof. Shukla had travelled to India to receive the prestigious Hind Rattan Award from Prime Minister Dr. Manmohan Singh. The award from the NRI Welfare Society of India honours the outstanding contributions of Prof. Shukla to his research area.
A German citizen, Padma Shukla would have celebrated his 40th anniversary at Ruhr-Universität Bochum, where he was head of the International Chair since 2010.
Read his eulogy on the Ruhr-Universität Bochum website.