Flying over the ITER site in the early autumn light, a drone captures both the unique setting of ITER in the Provencal landscape and the spectacular progress in construction.

Tremendous forces will be exerted on the ITER machine when plasmas begin pulsating inside the vacuum vessel. As a consequence, the machine's support system needs to be both extremely robust, with a strong connection to the Tokamak Complex basemat, and yet also accommodating to the wobbling, expansion and occasional displacement of 23,000 tonnes of mass (tokamak plus cryostat). A massive pedestal—connected to walls that are radially anchored into the three-metre-thick bioshield—will allow for the even distribution of loads and efforts; a set of 18 spherical bearings acting like ball-and-socket joints will allow for the smooth transfer of horizontal, vertical and rotational forces, whether stemming from normal operations, a vertical displacement event or an earthquake.   Spherical bearings (semi-spherical actually) are commonly used when large structures, such as bridges, need a small allowance of movement.   But while mechanical constraints can be compared, a tokamak's environment is quite different from that of a bridge: radiations and extreme temperature gradients (from 35° C down to minus 100) require specific materials and techniques.   At a facility near Milan, Italy, two full-size bearing prototypes have entered the qualification phase at Nuvia—the ITER contractor that also designed and installed the anti-seismic bearings of the Tokamak Complex.   Made of high-resistance steel, the 18 cryostat bearings play an essential part in accommodating the wobbling, expansion and occasional displacement of the 23,000 tonnes that represent the combined mass of the Tokamak and cryostat. In order to simulate the vertical compression forces that the bearings may be subject to a powerful hydraulic press, capable of delivering up to 7,000 tonnes (1) of vertical pressure, was purpose-built. Equipped with additional jacks, the press also simulates the cryostat's lateral and rotational loads.   An important factor in the behaviour of the bearings during both normal and incidental conditions is temperature. Because it can get as cold as minus 100 °C close to the bottom of the cryostat a small cryoplant has been added to the hydraulic press in order to inject liquid nitrogen into the test apparatus.   The latest qualification tests mark the last step before launching the fabrication in late November. Further tests will be carried out during the manufacturing stage on the actual production bearings.   (1) 7,000 tonnes represents about two times the force that could actually be exerted on each of the 18 individual bearings including safety provisions.

Nobody said it would be easy, holding up the fusion flag on a stage still dominated by the mighty oil and gas industry. But at the 23rd World Energy Congress (WEC) taking place in the city of Istanbul, Turkey, fusion was present.   Thomas Klinger, project director of the Wendelstein 7-X stellarator at Max-Planck-Institute for Plasmaphysics in Germany, took up the challenge and participated in a session titled "Technology Innovation Frontiers," where he made the C.A.S.E. for fusion, introducing fusion energy as a potential baseload energy option and explaining why fusion energy—in contrast to many other options—is clean, abundant, safe and economic.   The video-screen background of the vast stage in the Istanbul Congress Centre gave a stark reminder of what is at stake when discussing the future of energy: planet Earth, enveloped by its oh-so-fragile atmosphere. "Today we meet at a critical time," said the co-chair of the conference, Younghoon David Kim during his opening address, reminding participants that the global demand for energy is predicted to double by 2060. "Limiting global warming to no more than 2 °C will require exceptional and enduring efforts. We are moving from peak oil to peak demand; leadership at all levels is critical."

On Friday, 30 September, scientists and engineers at MIT's Plasma Science and Fusion Center (PSFC) made a leap forward in the pursuit of clean energy by setting a new world record for plasma pressure on the Alcator C-Mod tokamak. The results will be presented to the international fusion community by senior research scientist Earl Marmar at the IAEA Fusion Energy Conference that opens today in Kyoto, Japan.   Plasma pressure is one of the key ingredients to producing energy from nuclear fusion, which demands that the product of three factors (the so-called "triple product"—a plasma's particle density, its confinement time, and its temperature) reaches a certain value. Above this value the energy released in a reactor exceeds the energy required to keep the reaction going.   A time map of all pressures achieved since the start of operation. The record-setting plasmas and the recent high-performance campaign are apparent on the very top right of the graph. Source: PSFC Pressure, which is the product of density and temperature, accounts for about two-thirds of the challenge. The amount of power produced increases with the square of the pressure, so doubling the pressure leads to a fourfold increase in energy production.   In the plasma pulse run on 30 September, MIT and guest scientists were able to achieve 2.05 atmospheres of pressure, passing the previous world record of 1.77 atmospheres that had been achieved in 2005 on the same device. This result—an improvement of 15 percent—was achieved in a 35-million-degree plasma that lasted two seconds.   This pressure record is likely to stand until the operation of ITER, which is expected to reach 2.6 atmospheres when in full operation.   In the plasma pulse run on 30 September, scientists were able to achieve 2.05 atmospheres of pressure in a 35-million-degree plasma that lasted two seconds. The graph above shows some of the shot's properties. Source: PSFC Three different strategies for breaching the pressure record were tried by the engineers, technicians, scientists and students present in the control room. Two came very close to reproducing the previous mark, and the third set the ultimate record. Two of the approaches, including the record-setting one, were led by scientists from other laboratories in the US, including the Princeton Plasma Physics Laboratory, the Oak Ridge National Laboratory, and General Atomics in San Diego. Each approach was thoroughly planned before hand and attempted sequentially throughout the day.   "This is a remarkable achievement that highlights the highly successful Alcator C-Mod program at MIT," said Dale Meade, former deputy director at the Princeton Plasma Physics Laboratory. "The record plasma pressure validates the high-magnetic-field approach as an attractive path to practical fusion energy."   Alcator C-Mod is the world's only compact, high-magnetic-field fusion reactor of the tokamak variety. The device's high-intensity magnetic field—up to 8 tesla, or 160,000 times the Earth's magnetic field—allows the device to create the dense, hot plasmas and keep them stable at more than 80 million degrees. Its magnetic field is more than double what is typically used in other designs, which quadruples its ability to contain the plasma pressure.   C-Mod is third in the line of high-magnetic-field tokamaks to be built and operated at MIT. The result was achieved on Alcator C-Mod's last day of planned operation. The facility officially closed in September after 23 years of operation and approximately 33,000 plasmas.   Read the original report of the world record on the PSFC and MIT websites. 

The 26th IAEA Fusion Energy Conference kicked off today in Kyoto, Japan. The biennial rendezvous for fusion researchers from over 40 countries, the conference aims to highlight worldwide advances in fusion theory, experimental results, technology, engineering, safety and socio-economics. ITER Director-General Bernard Bigot spoke on the first day, presenting the progress in ITER construction, manufacturing and R&D to an audience of scientists, engineers, policy makers, and representatives of industry. Over 1,000 visitors are expected during the six-day event, hosted this year by the Government of Japan and organized by the International Atomic Energy Agency in cooperation with the Japanese National Institute for Fusion Science (NIFS). At the ITER stand, visitors will have the occasion to experience a virtual reality tour of the ITER construction site (Oculus Rift) and admire a Lego tokamak designed and built by students from Kyoto University. IAEA Director General Yukiya Amano (here with ITER's Julie Marcillat) was one of the first visitors to the ITER stand on Monday 17 October.

The Mega Amp Spherical Tokamak (MAST) facility at Culham Centre for Fusion Energy (CCFE) in the UK is undergoing a major upgrade that, once completed, will allow it to add to the knowledge base for ITER and experiment with candidate technological solutions for future fusion power reactors. The upgrade will permit longer pulse lengths, improved neutral beam heating, and new features to improve plasma profile control and the study of plasma instabilities. Recently, progress on the largest sub-system—neutral beam heating—was made as the internal components were installed into two neutral beam injector vacuum vessels. The team is now on schedule to have both beamlines finished by the end of the year. More information here: CCFE

At a specialized laboratory in Germany, electrical tests have been successfully performed on a 1/15th scale mockup of the high voltage deck planned for MITICA, the ITER-sized neutral beam injector that will be tested in advance of installation on ITER at the PRIMA neutral beam test facility in Italy. Positioned on four large gas-insulated columns at six metres above the floor, the 4 x 4 x 4 metre mockup was subjected to high voltage testing in order to validate the design choices of the European Domestic Agency supplier SIEMENS AG. In a 24-hour period, the mockup passed one long-duration test (5 hours at 1.2 million volts DC) and several short-duration tests (impulses of 50 micro-seconds at 2.1 million volts). The tests were designed to verify that the deck will sustain the different voltage levels that are expected during MITICA operation. Read more about the high voltage tests on the European Domestic Agency website. For more on PRIMA, click here.