ºÚÁÏÉçapp

A new series of aerial photographs, taken in the early hours of a bright August morning, reveals the spectacular progress accomplished on the ºÚÁÏÉçapp worksite over the last five years. Nested in the Cadarache forest, the ºÚÁÏÉçapp platform (pictured here looking southwest) is now teeming with activity: the roof structure for the Assembly Hall (in white) is being readied for installation in the first week of September, walls are rising in the Tokamak Pit; and groundwork has begun in the area of the cooling towers, the Control Building, the Radio Frequency Heating Building and the cryogenic plant. On the left side of the image, a 10,000 m² warehouse for the storage of ºÚÁÏÉçapp components is almost completed. Nested in the forest. © Matthieu Colin - http://www.matthieucolin.com/

One of the three "cold boxes" destined for ºÚÁÏÉçapp's liquid helium plant will bear, inscribed on its wall, an unexpected signature: that of François Hollande, President of the French Republic.   Manufactured by the Italian firm SIMIC, the cylindrical vessels (21 metres long, 4.2 metres in diameter) are currently being equipped with internal components such as heat exchangers, cryogenic adsorbers, liquid helium and liquid nitrogen phase separators at the Air Liquide factory in Sassenage, near Grenoble, France.   And it's the Air Liquide factory that the French President had chosen, last Thursday 20 August, to showcase his environmental policy in advance of the United Nations COP 21 climate conference to be held in Paris from 30 November to 11 December 2015.   ºÚÁÏÉçapp Director-General Bernard Bigot greets President Hollande upon his arrival at the Air Liquide Sassenage plant. © Le Dauphiné Libéré "What we're about to see in this factory are some particularly enlightening demonstrations on potential new energy sources, or energy savings," said the French President. Prominent among these "new energy sources" was fusion, in the form of the three giant tanks in different stages of completion in the great hall of the Air Liquide factory.   After a presentation by the Air Liquide management of the company's involvement in the ºÚÁÏÉçapp Project, the President, in the presence of ºÚÁÏÉçapp Director-General Bernard Bigot, decided to leave a souvenir of his visit. With a large black marker he signed his name on the steel wall of cold box number two ...

High Temperature Superconductor (HTS) current leads are key components of the ºÚÁÏÉçapp magnet system, transferring the large currents from room-temperature power supplies to very low-temperature superconducting coils at a minimal heat load to the cryogenic system. The HTS current leads for the ºÚÁÏÉçapp Tokamak are procured by the Chinese Domestic Agency through the Institute of Plasma Physics (ASIPP) in Hefei, China.   Following the signature of the ºÚÁÏÉçapp coil feeder Procurement Arrangement in January 2011, ASIPP launched a string of activities to prepare for series production, which began with the qualification of critical manufacturing technologies through targeted trials in mockups and which will conclude with the manufacturing and testing of several pairs of current lead prototypes this year.   In March, success was reported in tests on a pair of correction coil 10 kA current lead prototypes. More recently, and according to schedule, it was the turn of the toroidal-field-type prototypes. Tested at their design current of 68 kA, the technical challenges were significantly greater than during the previous test. In fact, it was the moment of truth for the ºÚÁÏÉçapp HTS current lead designs and for ASIPP's manufacturing team. Once installed in ºÚÁÏÉçapp, these leads—each weighing about 1.5 tonnes—will be the largest HTS current leads ever operated.   At ASIPP, the prototype toroidal field coil HTS current leads are installed in a prototype coil termination box. Also visible are the aluminium bars connecting the test station to the power supply. There was indeed reason to celebrate when, at the second attempt, the steady state operation test at 68 kA was successfully completed in early July. Following these tests, a further test program (specified by the ºÚÁÏÉçapp) was executed, often late into the night, which included operation at up to 75 kA and so-called LOFA runs in which the response of the lead to an interruption of the cryo supply is tested.   A LOFA time of more than seven minutes was measured for both prototypes under full current. Since the temperature rises in the current leads (as a result of the imbalance between Joule heating by the current and cooling—switched off during the test—in the resistive sections), this process also leads to a quench of the HTS tapes. After quenching (a break-down of superconductivity), the full current could still be flowed in the leads for almost 10 seconds before reaching the defined hot spot temperature of 150 K. All of the above testifies to a robust design with a healthy operating margin in the superconductor as well as sufficient stabilization during a quench.     The turn-key control system delivered by the ºÚÁÏÉçapp for the previous test campaign was also used in this test, including critical quench detection and interlock functions. ºÚÁÏÉçapp's Coil Power Supply Section also contributed by delivering a set of toroidal-field-type flexible copper busbars. ºÚÁÏÉçapp representatives participated in the test, remotely as well as on site.   The next and final step of the HTS current lead qualification will be the testing of poloidal field/central solenoid prototype leads (which use a common design). The tests are scheduled for the end of 2015.

The cryogenic test facility at Oak Ridge National Laboratory's Spallation Neutron Source (SNS) provided a unique environment for testing the performance of a 2.7-metre-tall, tritium-compatible cryoviscous compressor pump prototype designed for the ºÚÁÏÉçapp Tokamak. Initial testing, using deuterium to simulate tritium capture, occurred in late April. So far, the results show that a large portion of deuterium was successfully captured by the pump—a necessary part of the fuel recycling process in the ºÚÁÏÉçapp fusion reactor. "This is the first use of the cryogenic test facility for projects outside SNS," said Sang-Ho Kim, group leader for superconducting LINAC systems in the research accelerator division at SNS. "Our group has been collaborating with the US ºÚÁÏÉçapp roughing pumps team for several years, planning for this testing and discussing related technical issues." The SNS cryogenic test facility was commissioned in 2013 for superconducting radio-frequency cavity testing and can provide refrigeration down to 4.5 Kelvin, or about -273 °C, plus helium liquefaction at a flow rate of 240 litres per hour. These features contribute to an environment with temperatures, pressures and flow rates similar to the requirements of the ºÚÁÏÉçapp reactor. Robert Duckworth, a researcher with the ORNL plasma technologies and applications group within the fusion materials and nuclear systems division, oversaw the cryoviscous compressor (or CVC) pump testing. "The SNS cryo facility worked great," Duckworth said. A view of the test environment at the Spallation Neutron Source shows a white tank containing helium on the left, the prototype cryoviscous compressor pump in the middle, and the valve box, which monitors the flow rate to the pump, on the right. Photo: US ºÚÁÏÉçapp/ORNL "The SNS staff was very engaged and went above and beyond to assure that we had a positive test experience. The CVC performed well in its first full-scale test and was able to freeze deuterium with helium. We learned much that we can take and use for the final installation of the CVC at ºÚÁÏÉçapp." Ultimately, six cryoviscous compressor pumps will be manufactured and installed on the ºÚÁÏÉçapp machine. The primary fusion fuels that will be used on ºÚÁÏÉçapp are deuterium and tritium. The CVC pumps will take turns evacuating a mix of deuterium, tritium and helium from the ºÚÁÏÉçapp Tokamak in order to send the mix on to the tokamak exhaust processing system for fuel recycling. The pumps are "tuned" to freeze out all of the hydrogen-species gases so that fuels can be captured and reused."The CVC pump is like a cryogenic filter. Condensation and temperature makes a difference for what material is collected and what passes through the pump," said Mike Hechler, US ºÚÁÏÉçapp team leader for the vacuum auxiliary system and roughing pumps. The CVC pump needs to be able to handle the pressure and flow rates of the large ºÚÁÏÉçapp machine; these demands are beyond the capabilities of standard industrial pumps. The CVC serves as a link between the vacuum system and the primary cryopumps, which are basic industrial pumps.Next up for the roughing pump team is to complete testing analysis and determine what design adjustments are necessary to enhance performance of the CVC pump. Another round of testing at the SNS facility is anticipated. US ºÚÁÏÉçapp has already fabricated and delivered some roughing pump components to the ºÚÁÏÉçapp site, including two screw pumps and one roots pump. In addition, a wide range of vacuum testing equipment and electrical equipment, tokamak cooling water drain tanks, and toroidal field magnet system conductor have been fabricated and delivered by the US for the ºÚÁÏÉçapp facility.

​The European Domestic Agency for ºÚÁÏÉçapp is responsible for delivering four remote handling systems to ºÚÁÏÉçapp: the divertor remote handling system, the neutral beam remote handling system, the in-vessel viewing and metrology system, and the cask transfer system for activated components—in all, about EUR 250 million of investment. In July, the European agency announced that it had signed the fourth and final Procurement Arrangement for remote handling systems with the ºÚÁÏÉçapp—the Cask and Plug Remote Handling System. Responsible for confining and transporting the machine's activated in-vessel components, this complex system will interface with more than 50 different ºÚÁÏÉçapp systems and comply with the strictest nuclear safety requirements. The casks, which are automated, mobile containers weighing approximately 50 tons, will move equipment such as divertor cassettes and heating plugs between the Tokamak Building and the Hot Cell Building in order for them to be repaired, tested or disposed of. These transfer devices will need to be able to lift components weighing up to 45 tons and operate with high accuracy within a tightly confined space within the buildings. The procurement contract for a fleet of 14 units is expected to be awarded in 2016. Read the full article on the European Domestic Agency website.

​Registration is open through 1 October 2015 for the fifth FuseNet PhD event, which will take in Prague, Czech Republic from 15 to 18 November. The aim of the event is to enable students to disseminate their research, develop a network of contacts and learn from each other's experiences. Organized by the Faculty of Nuclear Sciences and Physical Engineering of the Czech Technical University under the umbrella of the FuseNet Association and with financial support by EUROfusion, the PhD Event 2015 brings together PhD students working in the field of fusion science and engineering. The PhD Event is open to all PhD students whose topic is associated with nuclear fusion research and registered at a European university, or at a FuseNet member university. Financial support for attending students is available, granted by EUROfusion through FuseNet, at the FuseNet website. More details will be posted on the registration form.   Registration is open online through 1 October 2015.