Two scientists from the Massachusetts Institute of Technology, Yijun Lin and John Rice, claim to have demonstrated an efficient method for using radio-frequency waves to make the plasma rotate inside a tokamak. Rotation would not only help to prevent it from losing heat to the walls but also prevent internal turbulence that could reduce the efficiency of fusion reactions. The results of the experiments are detailed in the 5 December issue of the journal Physical Review Letters.
But just how this method exactly works is yet unclear—so far there seems to be no satisfying theoretical foundation for why it works as it does. "This is a very interesting experimental observation," says Wayne Houlberg, Head of the Integrated Modelling Group within the ITER Organization. "It could be relevant to ITER's interest in controlling plasma rotation, which we know has a strong influence on plasma transport and stability. However, the result is very new and complex—its applicability to the deuterium-tritium (D-T) plasma conditions we expect in ITER will take time to evaluate."
The fuelling experts from the ITER Organization and external advisors recently met in Cadarache to discuss still open issues of the ITER fuelling systems. One of the most important and urgent topics the workshop addressed was disruption mitigation.
Disruptions can cause significant electro-magnetic and thermal loads on the machine and its structure. They can also trigger runaway electrons which are lethal for most in-vessel components. A reliable disruption mitigation system for ITER is thus essential.
One mitigation system envisaged is the introduction of massive amounts (~500 g) of particles, helium or neon for example, into the plasma within 10 msec. "This is quite an engineering challenge," says So Mruyama, Leader of the ITER Fuelling Section. There are three possible candidates to achieve this, namely gas injection, pellet injection and beryllium injection, but all have to be massive! "These are all well known techniques, but none of them has yet been demonstrated on the ITER scale and environment!"
ITER will be the biggest fusion furnace ever built. Its fuelling system basically consists of a combination of two techniques: a gas injection system and a pellet injector. The gas injection system releases hydrogenic and impurity gases into the vacuum chamber allowing the plasma control during operation. At the divertor level of the ITER machine, gas injections will enhance radiative heat transfer in the divertor region by introducing impurity gases such as neon and argon into the plasma. Gas injection will also help to control plasma detachment resulting in significant heat loads to the divertor. "We have to avoid high peak heat loads to the targets," says So. "What we strive for is to prevent plasma re-attachment to divertor, otherwise the its heat load will be lethal for the divertor material."
The second fuelling system, the pellet injector, is mainly an ice maker—though one with a very high efficiency. An extruder punches out several-millimeter sized deuterium-tritium ice pellets within that are propelled by a gas gun up to 3600 km/h, fast enough to penetrate deep into the plasma core. The Oak Ridge National Laboratory, which is responsible of the procurement of ITER pellet injector, has developed a twin pellet extruder demo and successfully demonstrated continuous deuterium ice production in March 2008.
Pellet injection is the main tool to control the plasma density and it also seems to be a viable option to control edge localized modes (ELM), highly energetic outbursts in the plasma. Only, to shoot the frozen fuel to where it is needed, for example into the high energetic zone next to the inner wall of the vacuum chamber, the pellets have to fly around the plasma following a bended pipe. The "flight tube experiment" set up in Oak Ridge tries to find out the best ratio of maximum speed to mass loss. A R&D program is set up to further develop a pellet injector prototype, which consists of the extruder, a pneumatic gas gun accelerator, a propellant gas recirculation and a fuel recovery circuit.
"Think IPT" it said on the power point slide that Ivone Benfatto, Head of the Electrical Engineering Division and Leader of the pilot Integrated Product Team (IPT) on power supplies, presented. Rather than the ITER Organization and the Domestic Agencies acting as two bodies—the one responsible for the Baseline documentation and the other one for placing the contracts with the manufacturers—the Management Advisory Committee to ITER (MAC) had charged both parties to collaborate more closely, to join forces and to think as one team: Think IPT!
The ITER Council had agreed in its last meeting in November to proceed with three pilot IPTs for the vacuum vessel, the blanket and the power supplies. Experts from the ITER Organization and the Domestic Agencies responsible for the power supply to ITER met last week for a first kick-off IPT meeting. In this first meeting the ground was paved for the future cooperation by identifying six key tasks that will have to be addressed soon in order to meet both schedule and scope.
One of the key tasks discussed was the standardization of components for the AC/DC power distribution. "In order to meet the projected target date for signing the Procurement Arrangement for this package in June 2009, we have to optimize the design and to standardize the components," said Ivone Benfatto. "By doing so we will also reduce the cost." The design of the AC/DC converter basic units is another task which was discussed in detail at the meeting and will be carried out by the IPT to optimize cost and performances of the power converters.
Many people buy cut evergreen trees during the holiday season. Well-watered trees are quite safe; however, a tree that is allowed to dry out in your home becomes a serious fire hazard. A dry tree is easily set on fire and can become a blazing torch within seconds.
To determine if a tree is too dry, grasp a tree branch with a reasonably firm pressure and pull your hand towards you, allowing the branch to slip through your grasp. If the needles fall off readily, the tree is not safe and should be removed from the house immediately. To prevent this from happening, keep the tree well watered.
Here are four tips for ensuring your cut tree remains fire safe:
• Keep the tree moist: After purchase, place it in water ensuring the cut is fresh. The container should be capable of holding at least four litres. Trees can be very thirsty; check the water at least once a day.
• Be careful where you put the tree: Hot air quickly dries it out. Keep the tree at least three feet away from heaters and open heating vents. Also, place the tree well away from any main exit paths out of your house.
• Use safe wiring: Approximately half of all Christmas tree fires are caused by an electrical malfunction. Make sure any electrical wiring in or below the tree is listed by a recognized testing laboratory and is in good working order.
• Keep a four-week limit: Don't keep the tree beyond about four weeks, as even a well-watered tree will begin to dry out significantly at this point.
Have a safe and happy holiday season!
The roadworks necessary for bringing the extra large ITER components to the site from the coast are in full swing. Work started at the beginning of 2008 and the aim is to finish it all before the end of next year, when the first convoys are expected.
Halfway through this large-scale project, work has started on the construction site in all the sixteen communes affected and some work, such as the adaptation of the roundabouts, has already been completed.
Organizing all this is a huge challenge. "Most of the work is being carried out on roads with traffic. Working on so many different construction sites simultaneously, ensuring the safety of both the workers and road-users and disturbing those living nearby, calls for real professionalism," says Alain Budillon, Director of the PACA Region team in charge of this project on behalf of the French Government.
If you would like to know more, you can look on the internet site: www.paca.equipement.gouv.fr under the heading "sites grands projets" where you will find "l'Itineraire ITER".
The construction of the rotogate that will connect the new ITER Headquarters with the ITER offices on the CEA site is progressing. But it will take another month until we can use the "hole" in the fence instead of driving all the way around Cadarache for a meeting. Once the gate itself is set up, access development work will commence followed by various tests and controls. The rotogate is scheduled to be fully operational from Monday, 19 January 2009.
The Fusion Power Associates (FPA) Annual Meeting and Symposium, "Fusion Energy: Countdown to Ignition and Gain," was held on the 3-4 December in Livermore, California (US), in honour of Lawrence Livermore National Laboratory (LLNL) fusion pioneers Richard F. Post and John H. Nuckolls.
At the meeting, the FPA Board of Directors presented them with FPA Special Awards for their "pioneering contributions to fusion energy development." Post and Nuckolls have been active fusion researchers since the 1950s and both have made seminal contributions to the fields of magnetic and inertial fusion, respectively. The meeting also hosted a 90th birthday celebration reception for Post. Families of both Post and Nuckolls took part.
At the symposium, Post and Nuckolls were asked to present their thoughts on fusion energy development to the audience.
Post said, "We have the basic scientific understanding, the computational horsepower, and the technology to take a new, broader look at the problem. And we certainly have the financial wherewithal. For example, we are spending $700 billion a year to import oil. One week of that rate of expenditure—$11 billion—is equal to the entire US magnetic fusion funding over its 56 plus years of existence. A four-tenths percent tax on that oil could pay for a fusion budget that is a factor of ten larger than the present budget."
Post and Nuckolls presentations are posted, along with other papers from the symposium, at
http://fusionpower.org and click on Annual Meetings and Symposiums,
or directly at: http://fire.pppl.gov.
A complete list of FPA Award winners is posted at http://fusionpower.org and click on Awards.
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On 1 September this year, Jean-Paul Clément became the new Director of the ITER International School in Manosque. With more than 200 children from 21 nations, and 65 teachers from ten countries, his charge as Director is not strictly academic. "What we need here is a cross-cultural approach to education in which we respect and celebrate the diversities of this multicultural community instead of its differences."
But for someone like Jean-Paul Clément, who has seen a good share of the world and who has worked in such exotic places as Madagascar and Australia, diversity is the spice of life: "So far, my professional career has been a learning journey."
Recently graduated from university, Jean-Paul Clément went to Berlin, Germany, where he stayed for one year teaching German to primary and junior high school children. After that he took a short side-step into administration at the Conseil d'éducation. "Then, at the age of 31, I decided to become a school principal." And he did! First as a deputy in Brignoles, then as the principal of a school in Nice. "This was not officially an International School," Clément says, "but it was very multi-cultural. In order to be able to communicate with the pupils we had to employ a mediator."
From Nice his "learning journey" led him to Madagascar where he worked in the Ministry for Foreign Affairs for four years steering the education cooperation between France and Madagascar. "My job was to implement a sense of responsibility in both students and teachers in order to empower themselves." In 2006, Clément moved Down Under, to Canberra, Australia, where he stayed for two years before coming back to France to take over responsibility for the International School.
After his first three months on the job he is still thrilled, unfazed by the complexity of the project. "With this school we are writing a new page in international education. We are setting new standards."
The development of the International School has reached another important milestone with the construction of the new building now well underway.
The school, currently with 212 students and 80 teachers and administrative personnel, is still hosted by the Lycée des Iscles, but that will change at the beginning of the new school year, when part of the new school will be completed.
The construction site, about 8 hectares in total, is located in the "Chanteprunier" district of Manosque, at walking distance from the Lycée des Iscles.
The first stone was laid in September 2008 and the first buildings will be ready by September 2009. At that time the primary school, administration, and the canteen will move to the new buildings. In January 2010, the nursery school will follow and in September 2010, ready for the new school year, both the junior high school and high school will also join, and all International School students will finally be under the same roof.
It all started with an American president meeting a Soviet Secretary-General and agreeing that cooperating in the field of fusion science was a promising way of easing tensions between their two countries.
The year was not November 1985 but June 1973; the place Washington D.C. and not Geneva, and the characters in the plot not Ronald Reagan and Mikhail Gorbatchev but Richard Nixon and Leonid Brezhnev.
This meeting, more than 35 years ago, was to lead to the first truly international effort to develop a large experimental fusion reactor. On 23 November 1978, the "Steering Committee of the INTOR Workshop" convened in Vienna for the first time and for the following decade, hundreds of scientists and engineers in the US, the USSR, Japan and Europe were to tackle such issues as tritium breeding blanket modules, divertor heat load and niobium-titanium coil winding.
INTOR—INternational TOkamak Reactor—was very close to ITER in its concept, and very different in its organization. "The INTOR Steering Group would gather two to four times a year at IAEA in Vienna," remembers Masayoshi Sugihara, then a young physicist at JAERI, the Japan Atomic Energy Research Institute. "They would dispatch what we called 'homework' to each of the national teams, which all had a specific area of expertise."
Each "national team" also had a large national project to devote their energy to: TFTR for the US, JET for Europe JT-60 for Japan, T-15 for the USSR. Nevertheless, each country started to grope for the next step to these large projects. "Everyone recognized that the next step to these machines was going to be very costly and no one was absolutely confident in their financial capacity to build them. So in a way, INTOR was a kind of safety net."
Andrei Kukushkin, who worked at the Kurchatov in 1978, says he "really believed in INTOR as a machine," but that three years into the project "things started cycling" and he felt his faith faltering.
For want of strong governmental determination, the INTOR Workshop never reached the design phase, and was eventually folded into the new ITER Project in the autumn of 1987. "ITER's figures today are not that different from those of INTOR," says Kukushkin. "But in ITER, there was a will to involve the people who actually do the work in the definition and design processes. INTOR's organization didn't allow that. And of course, the international collaboration today cannot be compared to what it was then ... even if, for me, INTOR was like a big window opened on the outside world."
Stefano Chiocchio is Head of the Technical Integration Division within the Project Office. Heading a team of 20 people, his task is to establish procedures to make sure the ITER design is conducted in an orderly way, controlled and verified at all stages, to manage the many interfaces and establish and control the project configuration as changes occur.
In other words, he sees his role as ensuring that ITER does not turn into the Tower of Babel in Breughel's famous picture, where one side is more or less complete and the rest is in chaos. "Communication is most important," he stresses. "There has to be a culture of integration instilled in the whole project," and by this he means both the ITER Organization and the Domestic Agencies. One example of the many activities undertaken by his team is work on design integration itself, concerning changes in configuration and design layout. Close collaboration with the design office is obviously essential.
A major objective for his Division is to streamline communications by making sure that access to the latest information/documentation can be given in a controlled and efficient fashion.
A nuclear engineer by training, Stefano worked on experimental fission reactors at ENEA in his native Italy before working in the nuclear industry. He moved to fusion research in 1988, working on ITER in all its different phases at Garching in Germany, before arriving at Cadarache in summer 2006. He lives near Luynes with his wife and two sons.
Two centuries ago, in 1794, an edict of the Convention, one of the political bodies born out of the French Revolution, expressly forbade public expressions of faith. Churches were closed and participating in a live Nativity scene, a Christmas tradition dating back to the early Middle Ages, became liable for punishment.
For several centuries, in churches and on the stage, simple folk had dressed as Joseph, Mary, the Angel, the Three Kings, and re-enacted the birth of the infant Jesus warmed by the breath of the ox and donkey in the Bethlehem manger. Now people had no choice but to respect the tradition in hiding, in the privacy of their homes.
Of course, there was much less room in a house than in a church and the live Nativity scenes, especially in Provence, were progressively abandoned and replaced with miniature "cribs" and "crèches" with wood or clay characters. This was how the "santon" came to be. These are the "little saints" that play such an important role in this region's Christmas traditions.
But then in the mid-19th century, a far-reaching movement developed in Provence, both political and literary, aimed at reviving the local language and culture. One of its leaders, Frédéric Mistral (who was to win the Nobel Prize for Literature in 1904), considered provençal as "the first literary language of civilized Europe."
Christmas traditions were a big part of this revival. Soon, new clay characters, typical of rural life in Provence, appeared in the crèche: the baker and the well digger, the knife grinder, the country priest, the Gypsy, the "Ravi"—a village idiot—and an Announcing Angel bearing the provençal name "Boufareù," meaning "the one who blows" (the trumpet).
These characters have become an integral part of the Nativity scene that every family, whether religious or not, places at the foot of the Christmas tree. One can meet them all, in various sizes and styles, at the santon fairs that are organized throughout Provence in the last weeks of December. Marseille's "Foire aux Santons"—the largest and most famous of all—has been held every single Christmas season since 1803.
The Joint European Torus (JET) is the machine whose parameters are the closest to those of ITER by virtue of its large size (~100 m³ plasma volume), ITER-like geometry and large plasma current (up to 5 Mega Ampere).
The JET design, which was started in 1973, introduced bold new concepts such as D-shaped plasmas in large tokamaks, a closed-loop tritium plant, and the use of beryllium as a first-wall material. It implied increasing by two orders of magnitude the plasma volume and the heating power compared to the standard at the time. One of the most striking novelties was that the machine was conceived from the beginning as a nuclear machine, allowing for tritium operation with full remote handling capability. The basic principles guiding the design of JET were simplicity and sturdiness. This philosophy was expressed in the JET founding document as follows: "First we must construct a simple apparatus with a very high reliability. Second, it must be possible to dismantle the apparatus from the outside using remote handling techniques."
Situated in Culham, UK, JET was built from 1979 to 1983 (First Plasma was achieved on 25 June 1983) with the essential objective to obtain and study plasmas in conditions and dimensions approaching those needed in a thermonuclear reactor. The studies were aimed at defining the parameters, the size and the working conditions of a tokamak reactor. The realization of these objectives involves four main areas of work:
(i) The scaling of plasma behaviour as parameters approach the reactor range;
(ii) The plasma-wall interaction in these conditions;
(iii) The study of plasma heating;
(iv) And the study of alpha-particle production, confinement and consequent plasma heating.
Throughout the years of JET exploitation, most of the design parameters were exceeded and after achieving all its initial objectives, JET was upgraded and modified to investigate the most promising regimes of operations and to perform comprehensive studies of heat exhaust techniques and plasma-wall interaction. JET holds all records in fusion power (16 MW) and energy (22 Mega Joule) and has allowed a unique experience in deuterium-tritium operation to be gained. The basic layout of ITER follows closely the one ultimately implemented on JET, and JET contributed the data points closest to ITER in the scaling laws used for its dimensioning.
JET today remains the only tokamak of its class that can use tritium and beryllium. On the basis of these assets, it is being prepared to make further essential contributions to ITER with regard to the aforementioned four main areas, i.e., qualifying ITER scenarios, consolidating the ITER design choice for plasma-facing components and heating systems, developing control tools and techniques, and providing a basic understanding of plasma dynamics.
Within the JET program in support of ITER, a set of enhancements of the JET facilities is underway with completion foreseen for mid-2010. An ITER-like wall and divertor will be inserted with the combination of metallic plasma-facing materials foreseen for ITER: beryllium wall and tungsten divertor. Experiments with the ITER-like wall and divertor should deliver answers to urgent plasma surface interaction questions for ITER, such as tritium retention, and provide operational experience in steady and transient conditions with ITER wall materials under relevant geometry and relevant plasma conditions. A high-frequency pellet injector system to mitigate the impact of transient power loads on first-wall components and divertor and to enable deep plasma fuelling was already installed in 2007. This system is currently being tested in JET experiments and the JET results and experience will give confidence to the foreseen use of such a system on ITER.
Also for ITER, JET is currently testing new matching tools for radio-frequency plasma heating in the ion cyclotron range with, for instance, an ITER-like antenna that has been designed to feature resilience to varying loads at the plasma edge due to transient instability events (edge-localized modes). Furthermore, the neutral beam power will be upgraded to ~ 35 MW and the pulse-length capability to 20 s. This will help progressing operating scenarios for ITER, in particular, the hybrid scenario and the advanced scenarios, which require full or partial current profile control, thereby making use of new dedicated diagnostics. After the testing of the ITER-like wall, a deuterium-tritium experiment is envisaged to allow extrapolation of the scenarios to ITER-relevant conditions. JET can bring its performance closer to breakeven (Q= fusion power/input power = 1) in stationary conditions, and such an achievement could be the best starting point for successful development of ITER operations.
In the coming years, until the upgrade of JT60-U into JT60-SA is completed, JET will be the largest tokamak of its class in operation; this would make it the ideal machine where scientists collaborating on ITER could start working together to develop a common strategy on ITER scenarios, where natural leaderships could emerge, and where researchers could be trained to operate a multi-Mega Ampere device. With these goals in mind, JET is being further opened up to the participation of all the other ITER Members.
On Monday, 15 December, members from the US Domestic Agency's Magnet Division visited the ITER construction site: Tom Mann, central solenoid project engineer; John R. Millwer, magnet system team leader; Nicolai Martovetsky, magnet systems; Charles Lyraud and Arnaud Foussat, both from the central solenoid magnet division within the ITER Organization (left to right).
On Friday, 12 December, Shinichi Ishida, leader of the JT60-SA project at JAEA came to visit ITER and had a look around the platform where the scientific facilities will be hosted.
On Wednesday, 10 December, members of the Korean National Assembly visited the ITER construction site. Jean-Michel Botterau, the technical Head of Agence Iter France, explained the progress of the works to Ahn Tae-Hun, Kim Hyun Jung, Yoon Sungshik, Seokbae Cheong, and Chang Ho Choi, member of the ITER Tokamak Department.
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