They may be small, but they have a big role to play in ITER. Pencil-sized micro fission chambers will be located close to the plasma to "count" neutrons during ITER operation—by measuring the neutron flux from the plasma, these highly precise devices will help diagnosticians calculate fusion power output. Each deuterium-tritium reaction in the ITER machine will produce one energetic helium nucleus and an even more energetic neutron. While the charged helium nucleus, also known as the alpha-particle, is immediately captured by the magnetic field and kept in the plasma, the neutron—with its absence of charge—will escape toward the wall of the plasma chamber. The energy of the alpha-particle is used to self-sustain the burning plasma; that of the neutron is ultimately the main output of the reactor.   Diagnostic physicists in ITER are interested in measuring neutron fluxes as they define the total fusion power. By measuring neutron emissivity, diagnosticians can provide important information to operators on reactor performance and operational profiles.   A number of neutron flux monitors will be positioned around the machine in diagnostic ports and both inside and outside the vacuum vessel to measure total neutron emissivity, expected to range from 10^14 n/s (neutrons per second) in pure deuterium (DD) plasmas and up to 10^21 n/s in deuterium-tritium (DT) plasmas.   Robin Barnsley (ITER ex-vessel diagnostics section leader), Luciano Bertalot (ITER neutron diagnostics physicist), Masao Ishikawa (micro fission chamber design developer, ITER Japan), and Vitaly Krasilnikov (ITER neutron diagnostics engineer-physicist) collaborate on the pencil-sized detectors that will have a big role to play in ITER. The most robust detectors for neutron flux measurements are the fission chambers. A fission chamber is an argon-gas-filled container, whose walls are coated with a thin layer of fissile material such as uranium 235 (U235) or uranium 238 (U238). When a neutron hits a uranium atom, the latter splits and a large amount of energy is released. As the energetic debris travels through the gas-filled volume of the chamber the gas is ionized, and high voltage applied to the electrodes inside the fission chamber results in a current that can be measured. In a later step, the value of this current is calculated into the fusion power of ITER.   In 2012 the ITER Organization signed a Procurement Arrangement with the Japanese Domestic Agency for the design, manufacture and supply of a diagnostic called micro fission chambers. Four units—containing three micro fission chambers each—will be fitted into the gap between the blanket shield modules and the vacuum vessel.   The neutron fluxes in the areas chosen for the micro fission chambers are extremely high, allowing for the detector modules to be extremely small, with low uranium content (hence the "micro" of their name).   Placing the micro fission chambers close to the plasma also helps to diminish the "scattering effect" and to measure the most direct neutron fluxes. When a neutron travels through material it can "scatter," losing part of its energy. The sensitivity of neutron detectors is energy-dependent; those that are installed far from the plasma are exposed to broad spectra of neutron energies, causing measurement accuracy degradation and making sophisticated neutronic calculations necessary for the interpretation of the data.   Given their location on the inner wall of the vacuum vessel, the front-end components of the detectors will have to be available on site in time for ITER's first assembly campaign when the vessel segments are welded together. It is vital that the installation of these components goes flawlessly, because once the blankets are installed there will be no access to the micro fission chambers for many years. R&D and prototype development are currently underway in Japan to ensure the reliability of all component parts.   Recently, the manufacturing of the mineral-insulated cables that will carry the signal from the detectors to the preamplifiers outside of the vessel was completed. These cables were exposed to 360°C temperature tests for many cycles, followed by vibration, bending, and helium leak tests. All the tests were passed with flying colours. Kiyoshi Itami, the responsible officer of Japanese diagnostic systems, concludes: "We are happy to have achieved this R&D milestone on time and plan to keep the same momentum up to the final delivery of the micro fission chamber system."   The micro fission chambers from Japan will be among the first diagnostics installed on ITER.

The scene is now familiar. It is a few hours before sunrise and a long procession of motorcycles, trucks and trailers slowly progresses towards the ITER gates. Everything is bathed is multi-coloured light ─ the pulsating blue of the Gendarmerie vans and motorcycles, the gyrating orange of the technical vehicles, and the blinding white of the headlights...   Familiar, but never routine. Every transport convoy—every "Highly Exceptional Load"—is an event in itself. After all, 300-ton loads (twice the weight of an Airbus A300) are not that frequent on the roads of Provence.   On Friday 10 June, at 3:30 a.m., the first of a series of three transformers arrived for ITER's pulsed power electrical network (PPEN)—the network that will feed power to the heating and control systems during plasma pulses.   Procured by the Chinese Domestic Agency, the three units are massive structures that will weigh approximately 460 tonnes each when completely filled with insulating oil and fitted out with the proper "bushings."

ITER will require significant fuelling capability to operate at high density for long durations. Pellet injection provides efficient core and edge fuelling of deuterium or a deuterium/tritium mixture; the system will also deliver deuterium pellets to the plasma edge to mitigate edge localized mode instabilities (ELMs).   The US ITER pellet injection team based at Oak Ridge National Laboratory (ORNL) has designed and fabricated a new dual nozzle test article that will support both fuelling pellets and ELM pacing pellets in the ITER Tokamak.   The article was manufactured by Apollo Corporation in Wartburg, Tennessee. The component features shut-off nozzles which permit the selection of 5 mm fuelling pellets or 3 mm ELM pacing pellets; it is also possible to adjust the pellet length in order to tailor the amount of fuel or ELM pacing material delivered to the plasma.   A test stand at the ORNL Pellet Lab is being prepared and testing of the component will occur later this year. In the ITER machine, the pellets cut from the dual nozzle assembly will travel through the pellet selector to the pellet guide tubes, which direct fuelling and ELM pellets to specific areas of the plasma.

With transparent skies and 300 days of sunshine a year, the tiny Alpine village of Saint-Véran (alt: 2,042 metres) offers a unique viewpoint on our own familiar fusion furnace. In the 1970s professional astronomers from the Observatoire de Paris used it to observe the Sun's corona with instruments they eventually donated to the village. Walking in the scientists' footsteps, the local population soon developed a passion for solar astronomy—an amateur club was created, more instruments were acquired through donations and the municipality soon decided to capitalize on its privileged relationship with the Sun. La Maison du Soleil was inaugurated on Thursday 9 June in the presence of French Vice-Minister for Higher Education and Research, Thierry Mandon, and of ITER Director-General Bernard Bigot. Designed for the general public, La Maison du Soleil will organize exhibits, conferences and solar observations. Nuclear fusion and ITER are of course part of the permanent exhibit, with posters, panels ... and even a conductor sample provided by the ITER Magnets Division. Saint-Véran is located in the heart of the Queyras Regional Park, two-and-a-half hours north of ITER.

The third edition of Introduction to Plasma Physics and Controlled Fusion by author Francis F. Chen is now available from Springer (follow this link). In addition to updates in all chapters, the 2016 release includes new chapters on special plasmas and plasma applications. A recent Chinese version of the 1973 edition of the book is also available here.

While the fusion community continues its quest to harness fusion for energy needs, numerous spin-off benefits are resulting from the research carried out all over the world. Given its complex, multidisciplinary nature, it should be no surprise that fusion research has driven advances in disciplines ranging from medical technology and environment to astrophysics and material sciences. EUROfusion, the European Consortium for the Development of Fusion Energy, has identified some of these spin-offs and put together a non-exhaustive list that demonstrates the short-term benefits of fusion research on the way to fusion electricity. Read more about them on the EUROfusion website or download an infographic.

Two types of cameras will be needed inside of the ITER vacuum vessel to support inspection and maintenance operations—oversight cameras that give engineers a broad view inside the vacuum vessel, and cameras embedded on tooling or robotics for a view inside tightly confined spaces. The European Domestic Agency for ITER is working with industry to develop purpose-built equipment small enough to fit into tight space constraints and capable of withstanding the harsh conditions close to the plasma. In a project called FURHIS (for FUsion for Energy Radiation Hard Imaging System), Europe is collaborating with Oxford Technologies (UK) to produce mockups of sub-systems that will soon be tested in a radiation environment. Working with French laboratories ISAE (image sensors), CEA (LED illumination system), and Université Jean Monnet (optic system), a 15 mm mockup—small enough to fit inside a one euro coin—has been developed. The FURHIS sub-systems will now be tested at the Belgian Nuclear Research Centre SCK•CEN. Read the original story on the European Domestic Agency website.