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ITER NEWSLINE 101
The design of the in-vessel coils is closely coupled to vacuum vessel procurement, and vessel interfaces must be clearly defined to allow this critical procurement to move ahead. The US Domestic Agency, specifically a team at Princeton Plasma Physics Laboratory, is leading this design activity in close cooperation with the ITER Organization. This is a very challenging activity because of the severe working environment of the coils and the very close interfaces the coils have with the vacuum vessel, the port structures, the blanket and the blanket manifolds. Important initial comments at the meeting indicated that we can move forward to the preliminary design phase, with the provision that the system requirements document is updated as soon as possible. More detailed comments will be provided with the final report in the coming weeks.
The final design review for the central solenoid conductor was completed on 17 September. Comments and recommendations from this review are being resolved with the expectation that the Procurement Arrangement with Japan can be signed in late October. This large Procurement Arrangement is worth about EUR 139 million; it will be the ninth conductor Procurement Arrangement signed between the ITER Organization and the Domestic Agencies. Conductors are an area where there is much activity going on at the Domestic Agencies, including the manufacture of ITER strand. Some of these activities are discussed in related articles in this issue.
Then, only a few hours ago we concluded the conceptual design review for the central solenoid magnet. This was a critical step in the process that will lead to a Procurement Arrangement with the US in the coming months. Much effort went to developing and finalizing the requirements for the central solenoid magnet, in addition to reviewing the baseline design and design alternatives.
Many more reviews of critical systems are planned in the coming months and this is a very good indication of design progress. This ultimately leads to Procurement Arrangements and the construction of ITER components, which is what the project is all about!
All the strands will be produced at the facilities of the Chepetsky Plant in Glasov. Cabling will be done at the All-Russian Scientific Research and Development Cable Institute (VNIIKP), using their innovative cabling technology.
The jacket and jacketing of the conductor will be done by a European supplier as an in-kind exchange with the European Domestic Agency—"an excellent example of collaboration between two Domestic Agencies and of optimization of procurement," ITER Director-General Kaname Ikeda said in his address prior to signing the contract. "Today's signature means that all but one Procurement Arrangement for ITER's poloidal field coils have been completed. The only Procurement Arrangement left to be implemented for the poloidal field coils is the one for the winding of coil number one. This signature is planned to happen by the end of this year."
In its second meeting, the committee discussed the implementation of the TBM Program into the ITER Research Plan, the planned ITER staff assignments for the TBM Program over the next ten years and the implementation of the TBM Program into the ITER Organization's working structure, including the creation of three port management groups. The plan is to set up one such group per equatorial port which will hold the TBMs. These groups are expected to be the main technical link between ITER Organization and the TBM teams.
During the discussion, we defined the target delivery dates for the Test Blanket Systems to the ITER site. Five out of six TBM are planned for delivery at the end of 2019, the sixth one is expected to arrive by 2022.
The TBM Program Committee further agreed on the revised roles of port masters as requested by the ITER Council. In the new proposal they were limited to technical roles related to integration aspects. The responsibility for the timely delivery and associated commitment has now been transferred to the TBM Leaders: there are two European leaders for the Helium-cooled Lithium Lead TBM and the He-cooled Pebble Beds (Ceramic/Beryllium) TBM; Japan is TBM Leader for the Water-cooled Ceramic Breeder (+Beryllium) TBM; China is the TBM Leader for the He-cooled Ceramic Breeder (+Beryllium) TBM; India is TBM Leader for the Lithium-Lead Ceramic Breeder TBM (LiPb & He, Dual-Coolant type); and the last TBM is not yet committed, but the US, with the help of Korea, is expected to provide all relevant information based on the Dual Coolant (PbLi & He) Lithium-Lead TBM.
Finally, the TBM Program Committee agreed on the ITER Organization proposal to organize a workshop in spring 2010 in order to decide on the need and the possible implementation of countermeasures for reducing the TBM ferromagnetic impacts on the plasma performances. Impacts might occur due to the reduced-activation ferritic/martensitic steel structural material used for all TBMs, which is ferromagnetic. Therefore, there is a TBM-induced magnetic field that creates some ripples in the main ITER magnetic field. As it is not clear what the level of acceptable ripples will be without degrading plasma confinement performances, experiments in existing tokamaks with ITER-relevant plasma scenarios are needed. DIII-D in San Diego is one of these machines and they have accepted to run experiments in mid-November 2009.
After the successful test of the fourth European sample EUTF4 in June 2009, the European Domestic Agency signed a first contract for the supply of more than 58 tonnes of niobium-tin (Nb3Sn) strand for the toroidal field conductors with Oxford Superconducting Technology this August. The quantity is equivalent to about 60 percent of the total European Nb3Sn contribution, and with a volume of approximately EUR 40 million, this contract represents one of the largest the European agency has placed so far for the ITER Project.
And there is more good news. This week, the EUTF5 sample made of Nb3Sn strand produced by Bruker EAS in Germany completed 1,000 load cycles with a final current sharing temperature (Tcs) above 6 K, thus meeting ITER's toroidal field conductor design criteria of 5.7 K.
"Because they are very conductive metals, silver or more realistically copper would have been the ideal choice," says Inho Song, an engineer with the Coil Power Supply System Division. "But of course, we had to consider cost. So we settled for aluminium, which is three times cheaper than copper and still offers relatively little resistance."
The biggest busbars—the ones that feed the 19 toroidal field coils in the machine—will carry close to 70 kiloamps of current, which is 7,000 times more than, say, a washing machine power cable. In these conditions, the aluminium's resistance to the electrical flow will generate heat, just like in a light bulb or an electrical heater,and the busbars will have to be cooled by a pressurized water system.
DC busbars are part of Russian procurement, and a real-scale prototype has just been produced at the Efremov Institute in Saint Petersburg. It is destined for the poloidal field coil system and will carry "only" 55 kiloamps. "We have design values for various parameters like current density, insulation, cooling requirements and temperature," says Inho. "We will test them all on the prototype in the coming months."
Project Manager Ned Sauthoff and ORNL Director Thom Mason were among those who paid tribute to Carl and his work, which included terms as Deputy Project Manager and Deputy Director at ORNL's Spallation Neutron Source, a $1.4 billion project that was completed ahead of schedule and within budget.
"Wherever Carl has served, he has combined a no-nonsense, take-charge style with thoughtful, caring leadership for his people," Ned said.
Other praise for Carl came from Federal Project Director Bill Cahill of the US Department of Energy's (DOE) Oak Ridge Office, who cited his "unique blend of both persistence and patience, particularly related to managing US ITER Project issues."
US ITER Program Manager Jeff Hoy of DOE sent a note thanking Carl for his "pivotal role" in building the SNS and launching US ITER efforts.
Gary Johnson, ITER Tokamak Department Head, sent a movie of ITER staff in which he called Carl's management style very direct and reasonable and always moving forward. "What I liked most about working with him was that I knew he would help if he could," Gary said. "He always did."
Carl is retiring after 11 years at ORNL. A graduate of the US Naval Academy, he also received a master's in mechanical engineering and naval architecture from MIT. He completed 25 years with the US Navy, retiring as a Captain after serving in numerous engineering assignments on ships, aircraft carriers, and nuclear submarines and in line industrial leadership positions.
All who know Carl and Linda, his wife of nearly 38 years, wish them much happiness as they embark on a new phase of their life from their home base in Maine.
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In-wall shielding consists of about 9,000 blocks made out of borated steel and ferromagnetic steel. The blocks will fill the space between the double walls of the ITER vacuum vessel and will perform the dual role of absorbing the neutrons generated by the fusion reaction within the plasma and reducing the toroidal field ripple, a periodic variation of the toroidal field from its nominal value.
Alan Kaye, former Chief Engineer at JET and now Chairman of the design review panel, indicates that the challenges of ITER's cooling water system lie not only in its sheer size—with a volume of 20,000 cubic metres, the cooling water basin will have the volume of about eight Olympic-size swimming pools—but also in its heat removing capacity. "During a Tokamak plasma pulse of 500 seconds duration, the water temperature in the basin could rise by 5 degrees Celsius," Kaye explains. "We have to remove a peak power 1200 MW of heat energy during one pulse," explains Kaye. "That is very near to the number you deal with in a commercial power plant."
The conceptual design review for the cooling water systems is the first step of a three-step process that will define the specifications and requirements enabling the issue of the Procurement Arrangement for the in-kind procurement of the system's components. The incorporation of design improvements identified during the conceptual design review and approval of their implementation by the ITER management will permit proceeding to the next step, the preliminary design, and will also permit the Indian Domestic Agency to issue contracts for their in-kind procurement equipment and components. The final step will then be the final design review giving all the necessary details to start with manufacturing.
But back to step number one—during the two-day meeting a number of design problems referred to as "chits" were raised which now have to be solved before the ITER Cooling Water Section moves to step number two scheduled for next year.
Like fusion science, the job Zahra held at AREVA TA in Aix involved a lot of electromagnetic equations. The transition from fluid circulation in nuclear reactors' rotating pumps to the physics of confined plasmas was made naturally. In the fall of 2008, Zahra found herself sitting on a hard bench in an auditorium at Saint-Jérôme campus, next to much younger students. "It was a great experience. Of course you worry about the performance in a learning context, but in fact, neurons work very well and experience compensates for flexibility ..."
The program that Zahra joined at the Université de Provence is the recently established two-year course in Plasma Physics. Students can choose between three majors: Magnetic Plasma Confinement, Inertial Plasma Confinement or Plasma Physics and Technology (PPF). Considering her experience, Zahra was granted a dispensation and did the PPF course in one year. "I still feel a bit frustrated though. So I've just registered as a free auditor in the Magnetic Plasma Confinement course ..."
Obtaining her Master's degree—27 years after getting her engineering degree!—led to an internship at the ITER Magnets Division, the Holy Grail Zahra had been pursuing since she decided to get an education leave from her job at AREVA. "ITER is like another world," she says. "There is diversity even in the ways people from different cultures address scientific issues. And there's understanding and tolerance."
In Building 507, Zahra got to work for six months on "theoretical formulations to characterize the critical surface in niobium-tin strands"—something that the PPF course touched on briefly. "It's about devising theoretical models that will reduce the amount of measurement points in the characterization process," she explains.
Reducing the number of those measurement points without altering the quality of the overall results means saving a lot on time and cost. "For the first time, we've done it," says Zahra. "I found that there was a new direction to explore, a solution that achieves this by way of mathematical tools. We brought down the amount of measurement points from more than 500 to less than 30."
Not bad for an intern. But now comes another challenge: "Joining ITER or a similar installation like CERN ... But first, I need a couple of days of vacation to take care of my house, my husband and my cats."
The completion of a dummy length is a key achievement, and a necessary step before cabling superconducting wires as part of the cabling procedure qualification. The toroidal field cable consists of more than 1,400 strands arranged in five, multi-twisted stages. The cabling is carried out in five stages on various types of cabling machines, the most impressive being the big planetary machine used to assemble the fifth stage. Takahaki Isono from the Japanese Domestic Agency and Denis Bessette from the ITER Organization attended this critical step at the Hikata worksite on 21—22 September.
The dummy cable was fabricated at a rate of approximately 1 metre per minute; the cabling work started at 5 p.m. on 21 September and ended at 4 a.m. on 22 September. Big cabling machines operate 24 hours a day! The cabling went very smoothly thanks to the preparatory work of Ishibashi-san from Hitachi-Cable and the skilled operators of JPS who managed to complete the unit length without damaging a single strand. After clearing the cabling procedure hold point, the Japanese Domestic Agency can now prepare for the next challenge: the cabling of a 100-metre toroidal field conductor unit length with superconducting wires for qualification.
In inertial confinement fusion (ICF), the fusion fuels are contained in tiny pellets that are compressed by an array of powerful lasers. On impact of the laser beams, the plasma instantly reaches very high density and temperature, fusion reactions occur and, as in magnetic fusion, energy is liberated.
The National Ignition Facility at Lawrence Livermore National Laboratory in Livermore, California, which was completed earlier this year, and the Laser Mégajoule in Bordeaux, France, to be operational by 2016, will demonstrate the production of energy from laser fusion. These facilities have been built in support of the requirements of the nuclear test ban treaty.
The installation to follow these has energy production as its focus. Now half way through its preparation phase, HiPER (the High Power laser Energy Research facility) has a goal to "open a credible route to inertial fusion energy for commercial purposes." HiPER's Executive Board held its fourth meeting last week at the Château de Cadarache.
"I'm convinced that both approaches, magnetic and inertial, will be realized," says Mike Dunne, Director of the UK Central Laser Facility at Rutherford Laboratory and Project Coordinator for HiPER. "Considering the energy challenge, we need as many solutions as we can deliver."
The HiPER project, which was launched in 2005, is now "halfway through preparation phase" and construction could begin in the early years of the coming decade. "For the moment, it's a UK-coordinated, European project. We have 26 institutions from ten different countries in the consortium. The real internationalization is the next phase ..."
One of the challenges HiPER will address is the "high repetition technology"—that is, aligning the nanosecond laser shots and the 1 millimetre diameter pellets five times per second. Something "relatively simple," says Mike Dunne, which should be achieved in the five to seven years to come.
Other challenges are not so different from those of magnetic fusion. "There is a huge amount of overlap with ITER. Because the physics of magnetic and inertial fusion were different, the two communities were separated. Now, they're coming together and we have a lot to gain from collaboration."
At the HiPER meeting last Friday at the Château, the Executive Board included Carlos Alejaldre from ITER, Francis Kovacs from CEA and several personalities from the world of nuclear science. "They are people from outside our field but with an experience with large projects. Their job is to steer us in the right direction to convince the world of the benefits of fusion."
On 25 September, a press conference given by Catherine Cesarsky, Haut-Commissaire à l'Energie Atomique, Kaname Ikeda (ITER), Colin Miège (Mission ITER), François Gauché (AIF) and Jean-Paul Clément, Director of the International School, kicked off the special "ITER Day." A series of presentations followed covering different aspects of ITER progress. The conference room was packed out during all the different talks—concrete proof of the great interest in ITER in the region.
The Foire de Marseille is open until Monday night, so take the opportunity to experience this exceptional local event and visit the ITER stand. Many thanks to all who worked hard to make ITER at the Foire de Marseille such a success.