For three days last week, the ITER building was brimming with energy, inspiration and enthusiasm. One hundred and thirty-five young fusion aficionados took over the ground floor to exchange with one another and with ITER experts about their common passion: the realization of fusion energy. For the sixth time, PhD students specializing in fusion energy got together under the umbrella of FuseNet, the association that coordinates European fusion education activities. This year, the event was hosted with the support of the ITER Organization and the French Alternative Energies and Atomic Energy Commission (CEA).   "This great challenge of fusion is what we need you for," said Roger Jaspers of the Eindhoven University of Technology, and the FuseNet program leader, at the outset of the three-day meeting. He advised the students to take full advantage of the gathering—to form networks ("Maybe the future director of DEMO is sitting next to you now!"), broaden their horizons, and see with their own eyes all around that fusion is becoming a reality.   A jam-packed program offered the students insights into some of the more challenging aspects of ITER: plasma-wall interactions, plasma disruptions, the use of beryllium, and tritium breeding. Students also heard about the challenges of the ITER Research Plan and learned about recent developments at Wendelstein 7-X and WEST.   For ITER Director-General Bernard Bigot—a former educator—it was a special treat to stand in front of a big crowd of young scientists and engineers "who have decided to dedicate their career to the quest for fusion energy." Telling the students about recent progress, Bigot said the ITER Project had met the 58 percent completion mark (to First Plasma) in September. "The second half will be very challenging and we will not enjoy the benefit of overtime."   Nearly every speaker referred to the tremendous task the 135 young fusion specialists will face in their professional lives to make fusion energy a reality. For co-organizer Roddy Vann of York University, the added value of the FuseNet event is that the students meeting today will be the people running the ITER control room in 20 years. Guido Lange, co-organizer and researcher from Eindhoven University of Technology, picked up on this theme in his remarks about socio-economic aspects of a future fusion industry. "Breakthroughs to make future fusion devices cheap, fast and tailored need to come out of your hands," he said.   The students did not just soak up information; they also shared their own work either as a poster presentation or in the challenging format of a Pecha Kucha talk.   It seems that some of the students are already contributing to the ITER Project: during the quieter intervals, quite a few ITER experts could be seen studying the posters.   Scroll through the gallery below for impressions from the event.  

Earlier this year, the Wendelstein 7-X stellarator fusion project reported record achievements from its most recent experimental campaign. Newsline spoke with the project's Scientific Director Thomas Klinger about the work behind the recent achievements, the preparations for the next experiments and the future of the stellarator. Earlier this year, in June, the Max Planck Institute for Plasma Physics (IPP) announced that it had achieved record results in producing a plasma. What led to this success?   The Wendelstein stellarator project is following a step-wise approach to full operation, much like ITER will. We have conducted two experimental campaigns and are now preparing for the third. We started the first experimental campaign in 2015 with somewhat of a "naked machine"—the machine was constructed, successfully commissioned and had created first plasma, but at that time, it was not yet equipped with proper plasma-facing wall components or a divertor. Instead, it just had a limiter and a metal wall.   Over the following 14 months, we worked on the divertor, the machine's exhaust system for extracting heat and particles, which enables us to control the density and the purity of the plasma. In addition, we installed graphite tiles in the areas of the vacuum vessel with higher heat loads.   The divertor and the in-vessel cladding were real gate-openers. We saw a whole new world. We could increase the heating power and achieve much longer plasma discharges, but we still had problems with obtaining high plasma densities. We identified the problem—oxygen impurities emanating from water released by the graphite tiles were strongly emitting light. We solved the problem by conducting wall conditioning by boronization (oxygen is "pumped out" by boron). All of a sudden we had clean plasmas, the oxygen light emission dropped by a factor of ten, and we were able to ramp up plasma densities to much higher values.   Consequently, in our most recent campaign in 2018, we could extend the pulse duration, achieving higher plasma temperatures and densities. With an input heating energy of 200 MJ we achieved a 30-second plasma at 6 MW, and at reduced power we achieved a 100-second plasma at 2 MW. These are among the best results achieved so far by any stellarator.   This CAD model shows all the intricate details of Wendelstein 7-X's future water cooling system. Image: IPP What are the next steps for the Wendelstein project?   These results were promising but have also shown limits. An input heating energy of 200 MJ is the maximum we can allow without causing damage to the wall components. The formula is simple: the heat generated by the injected energy has to go somewhere. So far, this happens by inertial cooling.   The next step is the installation of components in the vacuum vessel that are actively water-cooled. We will replace the current divertor with actively cooled divertor modules and will connect all wall elements to the water cooling system, which is a complex spider web of water pipes permeating the entire device (see image at right).   To prepare for these optimizations we are now in a two-year shutdown phase until the end of 2020, during which we will finalize the installation of the actively water-cooled system and start commissioning.   Tokamak vs stellarator: both projects will continue to be pursued in parallel ...   It's not a competition—we need to develop fusion as a clean, safe and reliable source of energy for the future. Both projects have their place in this ambitious endeavor and both systems have advantages and disadvantages.   The tokamak achieves better plasma performance in terms of temperature, density and confinement, but disruptions—now a major research topic in tokamak physics—can be a challenge. Stellarators on the other hand are disruption-free machines, however you pay the price by having to build a device with a challenging geometry. In the past, the performance of the stellarator could never match that of the tokamak, but it is now catching up and with upcoming optimizations some of the performance-related disadvantages can be overcome. This week you presented the Wendelstein 7-X project at the 6th FuseNet PhD meeting at ITER Headquarters. What did you take away from that meeting?   Fusion always has been, is and always will be a generation-spanning project. Fusion is a challenge too big to be solved within a lifetime. Therefore, we need to have handover from one generation to the next. In fact, it's already a very smooth process; there is a permanent transfer of knowledge to the younger generation of fusion experts. It was good to see that the students are looking at both fusion device options. There is a completely natural mix of study topics related to tokamaks and stellarators.   Read more about Wendelstein 7-X here.

Inside of the Tokamak Complex, a network of 2,000 small "fiducial target nests" will provide the reference datum for the dimensional control and alignment of machine components and plant systems. In the same way that the primary survey network established in 2010 on site provided a global coordinate system for civil engineering works and the positioning of the buildings, the ITER metrology team has now developed a vast matrix of reference "targets," or fixed points, inside the Tokamak Complex for use in measuring and aligning tokamak components and systems. These points are "materialized" by small magnetic discs called fiducial nests installed by European contractors inside the buildings. The nests are used to receive spherically mounted reflectors (SMRs), which are surveyed with laser trackers to establish their coordinate values and confirm their compliance with the simulation used during the network design process. This in-building network of reference points will represent the physical realization of the Tokamak Global Coordinate System (TGCS). "From any location in the Tokamak Complex, this coordinate system can be accessed by measuring a small number of reference points local to the measurement task. This is a powerful—and absolutely essential—tool for our installation contractors," says Lionel Poncet, metrology engineer within the Tokamak Assembly Division. Giacomo Calchi from the Fusion for Energy metrology team, shows us the size of a fiducial target nest—one of 2,000 to be installed inside of the Tokamak Complex. © F4E Starting from detailed CAD (computer-aided design) data for the buildings, the team used specialized software* to design and simulate the in-building matrix, establishing the exact location of each instrument station and plotting fiducial nests with clear lines of sight. A large number of stations and nests were planned as a way to reduce the uncertainty in the calculations. "We are using advanced software tools that allow the many lines of sight from the collection of instruments to be 'bundled' and 'weighted'—an analytic capability that actually permits us to optimize measurement geometries and minimize uncertainty to design values," says Poncet. The accuracy of the network has been measured within a global uncertainty range of 0.2 to 0.4 mm, allowing installation contractors to align components to sub-millimetre accuracy. European contractors are using data from the ITER Organization to install the fiducial nests progressively, beginning with the lower levels of the Tokamak Complex and moving up. The consistency, with the design, of the targets installed to date—approximately 1,000 out of 2,000—has been confirmed and their measured coordinates are about to be released for use by contractors. "This collaboration between the European Domestic Agency (Fusion for Energy) and the ITER Organization has proven extremely efficient and cost effective, ensuring continuity of the dimensional control process and providing independent qualification by the two metrology teams," says Dave Wilson, Metrology Group Leader for ITER. Currently the network is providing the reference frame for surveys of the as-built position of approximately 100,000 embedded plates by European contractors. Later this month, it will be used by an ITER contractor for the installation of the first machine component (a feeder segment) in the Tokamak assembly pit. *SpatialAnalyzer, from New River Kinematics. Inc. (US) Read a report from Fusion for Energy on the installation of the fiducial targets.

In the third week of November, the ITER Organization will be installing the first component of the machine in the basement of the Tokamak Building. The 10-metre, 6-tonne metal component is one segment of the magnet feeder that will relay electrical power, cryogenic fluids and instrumentation cables from outside of the machine in to poloidal field coil #4. The specific section to be installed, called a "feedthrough," will cross through the bioshield and cryostat at the lowest (B2) level of the building.   Delivered by the Chinese Domestic Agency to ITER last year, the component has undergone testing at the MIFI workshop (Magnet Infrastructure Facilities for ITER), which is operated jointly by a team from ITER and the French Alternative Energies and Atomic Energy Commission (CEA).   Most recently, the lifting operation was tested at MIFI using a specially designed tool delivered by the Korean Domestic Agency (picture). Next week the component will be transferred by truck to a staging area, and then lifted up into the circular assembly area and lowered down 30 metres to the floor.   Stay tuned for a report in the 26 November issue of the ITER Newsline on the first act of the machine installation phase.

The UK government has pledged to provide an additional £20m in 2019-20 to the UK Atomic Energy Agency (UKAEA), the public body responsible for research into nuclear fusion and the management of the country's largest fusion research laboratory, the Culham Centre for Fusion Energy (CCFE). "We think fusion has a big role to play," said UKAEA CEO Professor Ian Chapman. "The fuels are abundant around the globe, it doesn't release greenhouse gases and it doesn't produce long-lived radioactive waste like the nuclear fission power we have today." The 2018 Budget reaffirms the government's commitment to nuclear energy following an absence of new investments into the sector in the 2017 Budget. According to the World Nuclear Association, nuclear power accounted for 21% of UK electricity in September this year, however "almost half" of the country's 15 reactors are expected to be decommissioned by 2025. Read the full article  in "Power Technology" here. Photo: The Culham Centre for Fusion Energy (CCFE).

Thirty-seven seconds might seem like a very short duration—but not for a plasma, and even less for a plasma produced by a machine that is just commencing operations. The 37-second plasma that WEST obtained on 31 October exceeds by 7 seconds the first of five milestones ("Key Project Indicators") that were assigned to the machine on its way to final commissioning. The good news did not come alone—the final ITER-like, actively-cooled full tungsten divertor has just been ordered. It will replace the present non-actively cooled divertor made of tungsten-covered graphite blocks and only a few actively cooled test plasma-facing units. When this new divertor is installed, WEST will be able to produce ITER-relevant plasmas of up to 1,000 seconds.

At the Troitsk Institute for Innovative and Fusion Research (Moscow region), specialists have established a unique remote control panel that enables participation on leading fusion devices around the world. Based on the facility's lab complex for neutron and spectroscopy diagnostics, the panel will facilitate the creation and calibration of diagnostic systems for ITER under Russian procurement scope. The first cooperation line has been established with Europe's JET tokamak, based in Culham, UK.