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ITER NEWSLINE 246
Experts at Culham Centre for Fusion Energy (CCFE) have carried out the first-ever integrated assessment of the life expectancy of materials in a full-scale fusion power plant design.
The study focused on the effects caused by the build-up of helium in fusion materials. When neutrons from fusion reactions hit the materials in reactor components, they trigger nuclear reactions that cause transmutation (the changing of elements to form new ones). Helium is one of the gases produced by such reactions. The accumulation of helium causes swelling and embrittlement of materials—leading to fracture—and is one of the factors expected to limit the lifetime of components in a fusion power plant.
Materials modellers Mark Gilbert and Sergei Dudarev, working with CCFE specialists in nuclear data and neutron transport (Lee Packer, Jean-Christophe Sublet, and Shanliang Zheng) have conducted a pioneering study in which a fusion power plant design was explored and assessed using an integrated computational model that gives a detailed prediction of the lifetime of components under helium embrittlement.
The results will help guide the choice of materials for the design of DEMO, the prototype power plant that will follow the ITER experiment.
"We found wide variations between the behaviour of different materials," said Mark Gilbert. "The good news is that tungsten (the likely material for the 'divertor' plasma exhaust system in DEMO as well as ITER) shows low susceptibility to helium accumulation and embrittlement. However, in the iron of steels, for example, there is higher helium production in components bearing the brunt of neutrons from fusion reactions. The study highlights the need to develop materials with special microstructure, such as oxide dispersion strengthened steels that can resist the effects of helium accumulation without becoming brittle."
"We think the integrated approach we have adopted has worked well, and it will now help advance the EFDA materials program as a result."
The results of the work are published in Nuclear Fusion 52 (2012) 083019.
It all started on Lake Geneva with a promise. During the dinner cruise marking the grand finale of this year's Energy Security Congress, representatives of the ITER Project and the solar energy project Desertec shared a table. Two ambitious endeavours set up to secure the world's future energy supply through the power of the sun—one, by mimicking the process that powers the sun and other stars; the other by generating electricity from sun-drenched desert regions.
By the end of the evening, Oliver Steinmetz, one of the co-founders of Desertec who had (together with some 25 like-minded citizens) committed considerable private funds to start the Desertec Foundation, promised that one day he would come to Cadarache to see the ITER Project with his own eyes.
And so he did last week. After a crash course in fusion and ITER followed by a tour of the construction site, Oliver Steinmetz gave the first Inside ITER seminar in the new ITER amphitheatre.
The Desertec Foundation is an international non-profit collaboration of scientists, concerned individuals, and alternative-energy companies that believe that a combination of solar power from the world's deserts and othwer renewable power sources can provide all the electricity humanity needs. The idea is driven by a simple equation: Within six hours, the world's deserts receive more energy from the Sun that humankind consumes within one year.
"In order to meet today's global power demand (18,000 TWh/year), it would suffice to equip about three thousandths of the world's deserts with solar collectors," Steinmetz maintains. That's about 130,000 square kilometres of desert, shown as a small red square on Desertec's map of the Sahara desert—the same red square that has become the Desertec logo.
But the Sun's energy is not the only target of Desertec. Their concept calls for the utilization of all sorts of renewable energies wherever they are most abundant (e.g., coastal areas for wind).
Combined with sophisticated heat-storage technology, the power supplied by solar-thermal power plants can be made available day and night, complementing fluctuating renewable energy sources such as wind power and photovoltaics. A low-loss, high-voltage direct current transmission grid would connect—across great distances—the production location with the centres of consumption. These technologies are installed and running in the U.S., Spain, and China.
For the EU-MENA region (Europe-Middle East-North Africa), the Desertec concept assumes, given the political will, that by 2050 a substantial portion of the electricity needs of the local markets and around 17 percent of European energy needs could be covered by power stations in the desert. This would entail estimated investments on the order of EUR 400 billion. " This sounds like a lot, but that's roughly equivalent to Europe's annual oil import bill", the speaker stressed.
Before large-scale solar power plants and wind farms in North Africa and the Middle East with transmission grids reaching across to Europe become a reality, the political course needs to be set, and the first reference plants in the deserts initiated. This is why the Desertec Foundatio started its Industrial Initiative (Dii GmbH) in October 2009 in order to study and, where necessary create the framework conditions to enable international trading in climate-friendly electricity as well as suitable investment incentives. Among the 13 founding members were Deutsche Bank, Siemens, German energy giants RWE and EON, and the world's largest re-insurer, MunichRe.
The involvement of academic and research institutions in the EU-MENA region has since been promoted through the Desertec University Network (DUN) established in October 2010, which reunites universities and research facilities from Morocco, Algeria, Tunisia, Libya, Egypt and Jordan. Its aim: to contribute to the implementation of the Desertec concept.
At the end of his talk Oliver Steinmetz answered many questions on the maintenance of technology and the security of supply. "Delivering energy across borders—sometimes changing borders—is a matter of international cooperation and trust," he concluded. Words that were not unfamiliar to the assembled ITER staff ...
For more on the Desertec Foundation, see the project's FAQ section or download information material at http://www.desertec.org/en/concept/literature/
Click here to download the pdf of the presentation.
This kunzite crystal is not only beautiful, but it contains lithium, a raw material for fusion. In future fusion power stations lithium will be converted into one of the potent fusion fuels, tritium, by neutron bombardment.
Kunzite is a silicate that contains lithium and also aluminium. It also comes in shades of yellow and also a green variety, which is known as hiddenite. Hiddenite crystals can grow to huge sizes—the biggest ever found being over 14 metres long.
There are other lithium-containing minerals: rose or yellow coloured lepidolite, which contains potassium and fluorine, or red-brown lithiophylite, which is lithium manganese phosphate. These are all types of granite, an igneous rock formed by cooling volcanic magma or lava.
The total lithium content in the Earth's crust is estimated at between 20 and 70 parts per million (compared with the content in water of deuterium—fusion's other fuel—which is 35 parts per million). However the economically viable reserves are estimated to be a modest 13 million tonnes.
For comparison, the estimated viable uranium deposits amount to 35 million tonnes—but fusion gives four times more energy per kilogram than uranium. Even the vast coal deposits of the world, estimated at 860 billion tonnes, seem less extensive when you factor in that, per kilogram of fuel, fusion is four million times more efficient than coal at producing energy.
There is much speculation about how long the terrestrial deposits of these fuels might last, but it is perhaps irrelevant. The value of lithium as a potent fusion fuel will doubtless inspire new processing techniques which will enable extraction of lithium from sea water which will end the discussion. The estimated reserves of lithium in the ocean is 230 billion tonnes, several million years' supply.
This story was originally published on the EFDA website.
After Bratislava, Vienna and Liège, the Fusion Expo has moved into the centre of Aix-en-Provence, France, receiving hundreds of curious visitors during its first week.
With accessible explanations on fusion science, ITER, and the next category of fusion device—the fusion power plant—the Fusion Expo is designed for the general public. The Expo is staffed by members of the ITER Organization, the Cadarache-based Institute for Magnetic Fusion Research (IRFM), and Agence Iter France.
"With the ITER project under construction only 40 kilometres away, there has been great interest in the Fusion Expo," observed Michel Claessens, head of ITER Communication. "It has been a terrific opportunity to reach out to the local public and to communicate the importance of the world-scale energy project that is happening in their backyard."
Four roundtable discussions have been programmed to address specific aspects of the project. At last Saturday's session on "The Energy Challenge and Fusion," Michel Chatelier, former head of fusion research at CEA; Jean-Marc Ané, a CEA physicist at Tore Supra; and Richard Pitts, senior scientific officer in the ITER Plasma Wall Interactions Section, spoke to a full house, presenting their vision of the future and how they saw fusion fitting into it.
Combined with the exhibition, such roundtables provide the public with an opportunity to voice their questions and concerns directly to the actors involved. In this respect, Saturday's discussion was a great success.
The Fusion Expo is a travelling European exhibition funded by EFDA and the European Commission that has been operating since 2008 under the responsibility of the Slovenian Fusion Association.
You can visit the Fusion Expo through 28 November at the Office de Tourisme in Aix-en-Provence. Roundtable discussions (in French) are programmed on Tuesday 21 November, 4:00 p.m. ("Provence, A Magnet for Scientific Excellence") and Saturday 24 November, 4:00 p.m. ("Fusion and ITER: Scientific and Technological Stakes").See also "The power of the Director-General" on the EFDA website.
World experts on vacuum and fusion safety gathered last week at the ITER Headquarters for the Conceptual Design Review of the Vacuum Auxiliary Systems main delivery. "This is our most diverse Procurement Arrangement, covering 10 systems and including approximately 400 vacuum pumps situated all over the Tokamak Complex," explained Vacuum Section Leader, Robert Pearce.
The design of the systems was presented in 60 presentations over 3 long days. Liam Worth, review coordinator, expounds, "The review concludes many man-years of work by members of the ITER Vacuum team; preparations have been particularly intense over the last few months." Such work led to a successful review and Review Chair Alastair Bell commended the Vacuum team on its high level of preparation.
Passing this Review will now allow the Vacuum teams to progress to issuing the Procurement Arrangement for the systems, which should be ready to be signed between ITER Organization and the US Domestic Agency (US-DA) early next year. "Excellent," stated US-DA vacuum team leader Michael Hechler who attended the review with four other team members.