Listen here to the eerie sound of a critical heat flux in a plasma-facing component mockup. The plasma-facing components of the ITER divertor will be exposed to a heat load of some 10 to 20 MW per square metre, ten times higher than that of a spacecraft re-entering Earth's atmosphere. But a spacecraft's re-entry only lasts a few minutes, whereas ITER aims to realize hour-long plasma shots.   Spacecrafts like the Space Shuttle are protected from the searing heat by a blanket of insulating tiles that evacuate the heat by radiation; in ITER, the heat will be evacuated by pressurized water circulating through the divertor at the rate of almost one cubic metre per second.   Water enters the complex cooling circuit of the divertor at forty times atmospheric pressure (4 MPa) and at a temperature of 70 °C. As it exits, temperature has risen to 120 °C and the heat is evacuated by way of a heat exchanger connected to the secondary circuit.   "Pressurized water has the capacity to evacuate the heat flux but it is essential that the water does not fully boil—once vapour becomes dominant we lose much of the heat exhaust capacity," explains Frédéric Escourbiac, head of the Tungsten Divertor Section at ITER.   There is, however, a particular regime that is welcome by engineers: it is a condition called "diphasic," where micro bubbles keep forming and collapsing in the water circuit. "We want this regime because it is very efficient in terms of heat exchange and keeps the temperature of the structure within the desired range."   The diphasic condition, however, is an unstable regime: under certain conditions, micro-bubbles grow and coalesce into a large, stable, resistive layer of vapour. This is an unwelcome situation because, when it happens, a large part of the heat exhaust capacity is lost. "In a few hundreds of milliseconds the component can be damaged," says Escourbiac.   This event is called "critical heat flux," "boiling crisis," or "burn-out." It is a thermal phenomenon that suddenly decreases the efficiency of heat transfer, causing the localized overheating of a component. It can be caused by the depressurization of the cooling system, the failure of a pump, or a sudden change in the plasma regime leading to a significantly higher heat load—a phenomenon known as "plasma reattachment."   Frédéric Escourbiac and his team, along with experts from the French CEA Fusion Research Institute (IRFM) have been at work since 2010 to develop an advance warning system that will detect the precursory noise of the micro-bubbles on the verge of coalescing. (Drawing courtesy of Xavier Courtois, IRFM) Out of approximately 10,000 plasma shots, some 300 plasma reattachments are expected to occur in ITER during the first deuterium-tritium campaign, leading to heat loads up to 20 MW/m² for up to 10 seconds.   Although this estimation was taken into consideration when designing the ITER divertor to withstand heat loads of up to 30 MW/m2, Escourbiac acknowledges that "at 20 MW/m2, we're approaching the risk zone. It's acceptable, but we do not wish to enter into these conditions."   Experts from ITER and the French CEA Fusion Research Institute (IRFM) have been at work since 2010 to develop an advance warning system—a way of detecting the precursory noise of the micro-bubbles on the verge of coalescing.   At Areva's Technical Research Centre in Le Creusot, France, Escourbiac and his colleagues Sergey Bender and Alain Durocher use an electron gun to simulate the heat load (up to critical heat flux) that divertor components might be exposed to. They listen to the noise in the cooling circuit of a mockup and record the different frequencies to identify the indicator that will tell them that micro-bubbles are about to collapse.   "We have identified the precursory noise and we know where to install the 50-odd sensors that will be needed to monitor all the plasma-facing components," says Escourbiac. "The listening devices will be an integral part of the operational instrumentation, along with magnetic sensors, strain and stress sensors, thermocouples, etc."   Identifying the precursory signal of critical heat flux will allow for a swift counter-reaction: either halting operation or modifying the plasma regime before irreversible damage is done to the components.   The stakes are high: a damaged plasma-facing component in the divertor would mean at the very least a two-month interruption in operations.   Listen here to the eerie sound of a critical heat flux in a plasma-facing component mockup.

The European Domestic Agency for ITER, Fusion for Energy, has held a Final Design Review for the electron cyclotron system—one of the heating systems that will help to bring the ITER plasma temperature to 150 million degrees Celsius.   Manufacturing can now begin on the power supplies for the electron cyclotron system under European procurement responsibility.   The electron cyclotron power supplies convert electricity from the grid to regulated direct current and voltage at 55kV nominal, from which the ITER gyrotrons will generate electromagnetic waves. Europe is in charge of procuring eight sets of electron cyclotron power supplies with a total rated power of 48 MW. Another four sets will be supplied by India and the ITER Organization.   While many of the ITER components are manufactured by the Domestic Agencies on the basis of ITER Organization final designs, in some cases, ITER provides the functional requirements only. This is the case for the electron cyclotron system, for which Europe is responsible for the design and therefore also for conducting the Final Design Review.   The Final Design Review of the electron cyclotron system was led by an official review panel chaired by Michel Huart, the former head of power supplies at JET. In addition to international technical experts, representatives from Fusion for Energy and the ITER Organization with expertise in the areas of safety, control, quality assurance, electrical systems, gyrotrons, cooling, and buildings also attended, as well as representatives from Ampegon (the supplier selected last year by Europe to design, manufacture, install and commission the electron cyclotron power supplies) and gyrotron developers from Russia and Europe.   No major issues were identified and it is expected that all open questions will be clarified in the following weeks. Manufacturing will begin in 2015 for the first set of electron cyclotron power supply systems.   Read the full article on the European Domestic Agency website.

From 9 to 11 December 2014, the Control System Division hosted the 1st Technical User Meeting on the ITER control system. Over 150 people attended, including experts from the ITER Organization and all seven Domestic Agencies.   The ITER control system is the functional integrator of the project, composed of more than 200 local systems supplied by the ITER Domestic Agencies in the context of 89 in-kind procurement packages.   The integration of the individual systems into a coherent integrated control system to operate ITER is one of the project's major challenges.   The objective of the Technical User Meeting was to bring together the people who are designing and manufacturing the instrumentation and control (I&C) of the ITER plant systems. More than 30 presentations were given over three days, covering the magnet systems, coil power supply, heating systems, diagnostics, cryogenics, cooling water, vacuum, buildings and port plug test facilities.   The meeting was a unique opportunity to share and align the I&C design approaches that are employed by Domestic Agencies and their suppliers, to communicate about implementation difficulties, and to discuss missing features. Such quality exchange was especially useful for procurement packages like electron cyclotron heating or magnet system power supplies, which have particular integration challenges because they are split and delivered by several ITER parties.   The Control System Division received valuable feedback in the application of the Plant Control Design Handbook and on the use of CODAC Core System, which will allow it to fine-tune the priorities for the coming releases of ITER control system software.   Participants left the meeting with greater awareness of development work going on for ITER instrumentation and control around the world. This awareness will aid in the design and manufacturing of individual plant systems and, even more importantly, the integration of the systems in the final control system that will operate ITER.  

The second annual ITER Recognition Ceremony was held on Friday 12 December as a way to thank the ITER workforce for all the hard work accomplished during the year.   Hosted by Director-General Osamu Motojima and Carlos Alejaldre, Deputy Director-General for Safety, Quality & Security, the celebration go off to a start with a video that retraced the year's progress in pictures and celebrated the work, effort and commitment showed at all levels of the ITER Project.    The winners of the Ideas Network award. To recognize specific improvement contributions made in 2013-2014 to the project, a total of 27 commendations were given in three categories: cross-functional teams, improvements through the Ideas Network, and nominations—a new category added following a suggestion from staff, in order to enable them to thank their colleagues.   Commendation awardees (people or teams) were selected in a transparent process aligned to project priorities, as agreed by the ITER Organization directors at the Organizational Efficiency Steering Committee (OESC) and approved by the Director-General.   From left to right: ITER Director-General Osamu Motojima and the winners in the Nominations catégory: Alexis Dammann, Virginie Beaudoin, Matthew Kempton and Wolfgang Werner. The Recognition Ceremony concluded with an end-of-the-year celebration in the lobby of the Headquarters building, where refreshments and holiday treats were offered.   The Recognition Ceremony concluded with an end-of-the-year celebration in the lobby of the Headquarters building.

​In November, the Massachusetts Institute of Technology (MIT) announced a new director for its Plasma Science and Fusion Center, home to the Alcator C-Mod tokamak. As of 1 January 2015, Dennis Whyte, professor of nuclear science and engineering, will replace Miklos Porkolab, who returns to teaching and research after nearly 20 years as head of the research centre. In the announcement, Maria Zuber, MIT's vice president for research, thanked Porkolab "for almost 20 years of distinguished leadership and contributions to MIT and the fusion energy community worldwide." Whyte is a recognized leader in the field of nuclear fusion, with his research addressing the boundary plasma-material interfaces in magnetic fusion. He received his PhD from the University of Québec's National Institute of Scientific Research in 1993 and joined the MIT faculty in 2006. His recent research has focused on the novel application of high-energy ion beams for real-time material interrogation in fusion environments, and the use of new high magnetic field superconductor materials for compact, robust fusion pilot plants for electricity production. He was recently recognized with the International Atomic Energy Agency's 2013 Nuclear Fusion Journal Prize, which was presented at the 25th biennial IAEA Fusion Energy Conference last month, for research carried out on Alcator C-Mod. Read the full story on the MIT website.

On 5 December 2014, Osamu Motojima, Director-General of the ITER Organization, opened a day-long international workshop on remuneration. Organized by ITER's Human Resources Division, the workshop gathered over 40 participants from international organizations. The ITER Organization has been part of a coordinated system network of international organizations since 2008 and was pleased to act as host on this important occasion. The network organizes regular workshops for human resource professionals and legal specialists in the fields of remuneration and pension, enabling international organizations to share their experience and forge valuable contacts. 

Inside of ITER's large D-shaped toroidal field coils, the stacked layers of conductor will be held in place by radial plates—large steel structures with grooves machined on either side.   In 2012, the European Domestic Agency awarded a EUR 160 million contract for the fabrication of 70 radial plates to a French-Italian consortium, CNIM (France)-SIMIC (Italy) and manufacturing is currently underway.   In this promotional video produced by CNIM, the camera takes us inside the 3,000 m2 factory in Toulon, France that was specially constructed for CNIM's share of the radial plate contract. One radial plate comes off of the manufacturing line per month, thanks to a team of 50 skilled employees organized in three shifts.   Three years of investment in R&D and industrial processes and the construction of a 9 x 36 metre machining centre were necessary to perfect the highly technological machining and welding of the ITER radial plates.   View the CNIM video here.

​The Mega Amp Spherical Tokamak (MAST) facility at Culham Centre for Fusion Energy (CCFE) is undergoing a major £30 million upgrade that will enhance the UK's role in international fusion research. When completed in 2015, MAST-Upgrade will enable scientists to: Make the case for a fusion Component Test Facility (CTF). A CTF would test reactor systems for the DEMO prototype fusion power plant, and a spherical tokamak is seen as an ideal design for the facility; Add to the knowledge base for ITER and help resolve key plasma physics issues to ensure its success; Test reactor systems. MAST-Upgrade will be the first tokamak to trial the innovative Super-X divertor — a high-power exhaust system that reduces power loads from particles leaving the plasma. If successful, Super-X could be used in DEMO and other future fusion devices. In December, the second of four poloidal field coils was installed as planned. All four coils should be in place early in the New Year. Read the story on the CCFE website.