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ITER NEWSLINE 244
On Wednesday 31 October ITER Director-General Osamu Motojima and Jean-Marc Filhol, acting head of the European Domestic Agency's ITER Department, signed the Procurement Agreement for the Divertor Remote Handling System (DRHS).
The DRHS provides the means for remote replacement of the ITER divertor system. The divertor handling concept relies on the use of heavy remote handling transporters known as "cassette movers" and dexterous, man-in-the-loop tele-manipulators. The former are required to achieve high-accuracy transport of the 8-12 tonne in-vessel components from their entry point to their operational position in the vacuum vessel. The latter are required to precisely deploy a variety of mobile tools for pipe maintenance, (un)locking of the cassettes from the toroidal rails, (dis)connection of diagnostic cabling, etc.
The DRHS makes use of the remote handling transfer casks to allow safe transport of contaminated/radioactive in-vessel components to and from the Hot Cell Facility.
Due to severe space constraints within the vacuum vessel remote handling port and the lower part of the plasma chamber, it is necessary that cassettes be handled in a cantilevered way. This generates extremely challenging design requirements on the divertor remote handling equipment, both in terms of high mechanical loads and payload position accuracy. The gaps between cassette and vacuum vessel structure may be as small as 12 mm top and bottom at certain points during the transport trajectory.
After operations, the DRHS will be decontaminated, maintained and stored in the ITER Hot Cell. Re-qualification/commissioning of the system will take place on full-scale mockups within the Remote Handling Test Facility (RHTF), also to be located in the Hot Cell building.
The ITER team and a number of European institutions have been working on the development of the ITER divertor maintenance concept for more than 15 years. The most challenging steps within the process have been demonstrated at full scale, first within the DTP (Divertor Test Platform) constructed in Brasimone, Italy (ITER 1998 design), and more recently within the DTP2 located in Tampere, Finland (ITER 2001 design). This long concept preparation period is now over and with the signing of the Procurement Arrangement and the engagement of an industrial supplier in the next few months, the task of establishing a fully comprehensive, industrialized set of equipment for the remote exchange of the ITER divertor begins.
At the Belgian Nuclear Research Center SCK•CEN in Mol, engineers and scientists are developing a system that should enable ITER to measure plasma current in a new fashion. In contrast to the present-day inductive system, the measuring principle developed by the Belgian researchers is ideal for very long shots or even steady state current measurements without the need of signal integration with time.
The measurement is based on a fully optical principle: polarized light is launched in an optical fibre. Following Faraday's law, the light polarization plane is rotated if a magnetic field is applied along the light path. By surrounding the vacuum chamber with a fibre loop, the current of the plasma is completely enclosed. It follows from the Ampere law that the total rotation angle is directly proportional to the enclosed current.
Up until now such systems were only applied for much lower currents and in environments less harsh than that of the ITER Tokamak where radiation, temperature, vacuum, vibrations etc., make existing designs unusable.
The SCK•CEN, with a long experience in radiation-resistant fibre optics, with the support of the ITER European Domestic Agency F4E, is pursuing a sensor design based on fibres with limited sensitivity to radiation. As, due to the environment, it can't be ruled out that the optical fibre may be compromised (i.e., a darkening of the fibre due to irradiation), the sensing fibre could be replaced by a simple intervention from outside of the cryostat: the fibre, installed in a stainless steel tube, could be replaced using a pressurized-air fibre blowing technique. If so, ITER would have the benefit of a measurement system that is easily replaceable.
In practice, however, designing a suitable fibre blowing system in compliance with ITER geometry is a serious engineering challenge. To test the design on a real scale the SCK•CEN installed a 12-metre-high x 7-metre-wide cross-sectional drawing of ITER and positioned the stainless steel tube that will guide the fibre optics along its path around the vessel. The first tests showed that the principle is realistic and will allow for easy replacement of the fibre. The Fiber Optics Current Sensor (FOCS) principle demonstration also comprises ongoing tests at Tore Supra and Textor.
If successful, these efforts will result in the installation of three such measuring fibres around the ITER vacuum vessel. The engineering challenges are being addressed in a collaboration between SCK•CEN and the IRFM (Institut de Recherche sur la Fusion Magnétique) in Cadarache.
While plasma current measurements are a traditional diagnostic technique, the SCK•CEN researchers are investigating whether further information can be gleaned from the light signal travelling along the fibre. Detailed analysis of the return signal may result in information on the distributed magnetic field and temperature variations. Possibilities that are still under development ...
The 2012 Synergy Conference was held in the Indigo2 Arena in southeast London on 1 November. The event was sponsored by the UK Chapter of the Project Management Institute (PMI) and was attended by project management professionals from the UK and Europe. Her Royal Highness Princess Anne was a special guest in support of project management as a discipline. Speakers included members of the British Parliament and industry and focused on a variety of project management topics, including lessons learned from the 2012 London Summer Olympics.
As part of the program, Joe Onstott from ITER's Finance & Budget Division was invited to present ITER as an ongoing project of global interest. The talk presented the overall case for fusion energy; the ITER project; some of the challenges ITER faces; and a brief update of construction activities in France and manufacturing activities for ITER around the world.
Chinese noodles, Russian borscht, Japanese sushi, Indian curries, Italian pizza, Korean kimchi or American hot dogs: you name it, the ITER canteen cooks it. Last week, with the opening of the brand new canteen in the new ITER Headquarters Building, another milestone in the moving process of all ITER staff onto the ITER site was reached.
The large restaurant area, with dining space for close to 500 people, offers an exceptional view of the Durance Valley. But that is not the only exceptional feature of the new canteen. One of the key characteristics is the diversity of its offer: international food to reflect the diversity in nationalities and cultures of the ITER staff.
The expression "international cuisine" takes on a completely new definition in the ITER canteen where one can find an Asian, vegetarian, Western, pizza, salad and grill counter to please the taste buds of staff from each ITER Member state.