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ITER NEWSLINE 225
The ion cyclotron resonance heating (ICRH) system, one out of three heating systems installed in ITER, will deliver 20 MW of radio frequency power to the plasma for up to one hour. The power will be injected at radio frequencies through what we call "antennas," however, ITER antennas have very little in common with the one attached to the standard radio in our kitchen. These components will measure 1.8 x 3.5 x 2.5 metres and weigh 45 tons (dry weight). And—who would have guessed—there is some very sophisticated technology hidden inside the beast.
It is Europe's responsibility to deliver two of these high-tech components to ITER. In 2010, the ITER Organization signed a Task Agreement with the European Domestic Agency which, in turn, signed a contract for the "build-to-print" design of these impressive antennas with the CYCLE consortium, made up of several European fusion associations with ICRH expertise: CCFE, UK; CEA, France; ERM, Belgium; IPP, Germany; and ENEA-Torino, Italy.
On 22-24 May, more than 50 people—including experts on ion cyclotron radio frequency design, engineering, and physics; representatives from the European, Indian, and US Domestic Agencies; technical representatives from interfacing ITER systems; and, of course, members of the CYCLE design team—met in Cadarache to review the preliminary design. The review panel was chaired by Jean Jacquinot, former director of JET and one of the pioneers of the ICRH technology.
The design of ITER's ICRH antennas will be the quintessence of technologies developed for machines like Alcator C-mod, JET, Asdex-Upgrade, TEXTOR and Tore Supra. "The challenge in designing such an apparatus for ITER is not only the power increase to 10 MW for each antenna and the associated large electric fields," explains Jacquinot, "but the fact that this is a plasma-facing component that has to withstand neutron bombardment and high heat fluxes from the plasma. In addition, these components will require permanent water cooling and they will have to squeeze into an equatorial port plug, allowing only very tight tolerances."
"We try to make use of available technology as much as we can," ITER's Ion Cyclotron Section Leader Bertrand Beaumont comments. "But of course some new developments are necessary, such as the Faraday screen—a sandwich-like structure made of beryllium, hardened copper alloy, and stainless steel that covers the front face of the antenna."
"One of the open questions that call for further study is the behaviour of the ceramic vacuum windows in a nuclear environment," adds Philippe Lamalle, technical responsible officer for the antennas.
"The design review was an excellent and in-depth review of the antenna system, showing us that we are on the right track," said Dharmendra Rathi, technical officer for the system, at the end of the meeting. With no showstoppers identified, the ICRH team will now prepare for the next mileston: the final design review scheduled for 2015.
With its layer of soft soil removed, the ITER Assembly Hall work site looks a lot like the surface of an alien world. Fine white dust and sharp debris cover the ground. Methodically boring holes deep into the substratum, a lone, insect-like drilling rig adds to the illusion. With a bit of red in the sky it would be easy to believe we were walking on Planet Mars ...
Located adjacent to the temporarily deserted Tokamak Seismic Pit, the Assembly Hall area is the site of the latest construction campaign on the platform. This 60 metre by 100 metre rectangle of earth will host the 57-metre-high edifice in which ITER components will be assembled prior to their installation in the Tokamak.
As a follow-up to the scrapers, excavators and dump trucks that removed some 10,000 m3 of soil in three weeks, the drilling rig is carrying out "soil investigation." Long drill bits are being pushed as deep as 7 metres below the surface in order to identify possible discontinuities or cavities created by water erosion (karsts).
The rig will drill a total of 500 holes, collecting and transmitting data to the Engage/Fusion for Energy/ITER Organization team that manages the project. Geologists will then assess the rock profile and determine what treatment should be applied.
A month from now, workers will begin to pour a layer of blinding concrete over the 6,000 m2 surface. Foundation work will then begin in earnest.
Although less spectacular than those of the Tokamak Pit (no seismic pads will be installed), the foundations of the Assembly Hall will carry their fair share of challenges. The basemat (2.2 metres thick at the perimeter and 1.2 metres thick in the centre) will have to accommodate openings, or "penetrations," for electrical galleries, drainage, piping, and tunnels to service the neighbouring Tokamak Complex.
"Due to the challenge of ITER itself, it was necessary to incorporate a lot of flexibility in the design of the penetrations," says Miguel Curtido, Fusion for Energy's technical project officer for the Assembly Hall. "Space has to be reserved for them early on, when we begin installing the iron rebars prior to pouring concrete. The same holds for the anchor plates for the assembly tooling, which have to be embedded in the concrete. Their definition can still evolve."
Coordinating action on the Assembly Hall foundations and on the nearby "TB-alpha" worksite (more galleries and tunnels) that will open two months from now will be another big constraint to work with. "This will be the first time we need to manage the interfaces between different contractors working in such close proximity, which can drastically impact execution methodology."
Progressively, the barren, Mars-like landscape will give way to one of the most spectacular construction projects on the platform—the dramatic antechamber to the Tokamak Building.
ITER, the world's largest international research project, is not only a technical and diplomatic challenge. For the employees from more than 27 countries who—together with their families—have moved to southern France, it is also a cultural experiment. How will their relatives settle in this foreign country? How will their children adopt to a new language, a new school system and, finally, a very different curriculum from what they are used to?
"As we are aware of the challenges of living abroad, we are pleased to hand over some 30 Korean school books that shall enable families to measure their children's scholastic achievements and to catch up with the curricula when they return to their home country one day," Head of the Korean Domestic Agency, Kijung Jung, said during the small handover ceremony that took place at Manosque's Provence-Alpes-Côte d'Azur International School last week.
More than 200 books had been donated last year and the next donation is already in the planning. At the request of some involved mothers, Kijung Jung is likely to have some books on cultural studies and liberal arts in his suitcase on his next trip to Cadarache.
While the ITER machine itself is still a few years away from its first plasma shot, ITER's CODAC system recently celebrated its contribution to the first plasma discharge at the Frascati Tokamak Upgrade (FTU) Project in Italy.
As with so many good things in life, the cooperation between the two projects came about by coincidence. During a meeting held in Aix-en-Provence in May 2010, the ITER CODAC team had presented its EPICS project, as well as the first hardware standards to be used in ITER plant control. It soon became apparent that these hardware standards were the same used by the control and data acquisition group in Frascati to upgrade the slow control of one of their major facilities, the Motor Flywheel Generator 1.
The idea to test the slow control architecture developed for ITER on a running device was soon born. The advantages of this collaboration were mutual: the ITER CODAC Section could benefit from a "real world" experiment to test its slow control software suite, while the FTU team would gain expertise on the CODAC software environment and EPICS-based frameworks, permitting a refurbishment of the legacy control system.
The Motor Flywheel Generator 1 is a motor flywheel generator powering the FTU's 8T toroidal magnet. To give a rough idea of the size of this plant, the plasma current induced by MFG1 is approximately 38 kA, equivalent to the current flowing in about 38,000 apartments. Its control logic can be reasonably isolated from FTU's supervising control system, making the Flywheel Generator the ideal candidate for this kind of test.
In order to prepare for the test, every component of the Flywheel Generator control system was replaced to comply with ITER CODAC standards, from the controller interfacing the plant—the so-called PLC — to the synoptic panels that operators use to issue commands and monitor the plant activity. Quite obviously, all this work was done in parallel to the already existing MFG1 control in order to avoid unwanted disturbances with FTU experiments. To complete the picture, a new software interface was developed to allow the new system to communicate, when necessary, with the existing FTU control system (typically, during the plasma experiments).
After the first test runs that helped to refine the details, two weeks ago the new MFG1 control system was put online. On 23 May, the ITER CODAC slow control architecture made its debut at FTU, contributing to producing the first ITER CODAC plasma discharge.
The ITER Organization, together with the University of Provence and the Institute for Plasmaphysics in Gandhinagar, India, are glad to announce the 6th ITER International School that will be held in India from 2-6 December 2012. The school aims to prepare young researchers to tackle the challenges of magnetic fusion devices and to spread the global knowledge required for a timely and competent exploitation of the ITER physics potential. This sixth issue of the ITER International School will focus on radiofrequency heating and current drive in plasmas.
"We are very happy and honoured to host the ITER International School in India this year and we aspire to keep the excellent academic standard set by previous schools in this series alive," says Abhijit Sena, the joint director of the ITER International School and the host of this year's event. "The theme of 'Radio Frequency Heating and Current Drive in Plasmas' is rich in content—both physics and technology—and should serve to provide an exciting learning experience for the young participants."
For more information on the 6th ITER International School click here.
* Topic: RF Heating & Current Drive in Plasmas
* Date: 2-6 December, 2012
* Location: Institute for Plasma Research, Gandhinagar, Gujarat, India.
* Website: www.iter-india.org/iis2012
* Contact: email@example.com