ºÚÁÏÉçapp

At the northeast end of the ºÚÁÏÉçapp site, in a zone not far from the Tokamak Complex and Assembly Hall, workers are busy installing rebar reinforcement, pouring concrete and erecting walls and columns. The 6,000 m² area will be home to the final link in one of ºÚÁÏÉçapp's most widely distributed plant systems—the cooling water system, whose kilometres of piping, closed and open loops, and heat exchangers will collect and reject the heat generated by the Tokamak's plasma pulses and the operation of its auxiliary systems.The cooling water zone on the ºÚÁÏÉçapp platform will accommodate cold and hot basins with a total volume of 20,000 m³ as well as an induced-draft cooling tower (made of 10 independent cells) located above the cold basin. The cooling water zone is the final link of the ºÚÁÏÉçapp cooling water system—the ºÚÁÏÉçapp plant system responsible for collecting and rejecting the heat generated by the machine and auxiliary systems. With the exception of the civil works, which are under Europe's responsibility, the cooling water systems in this zone are part of India's procurement to ºÚÁÏÉçapp and will be installed by the ºÚÁÏÉçapp.The heat that needs to be evacuated from the ºÚÁÏÉçapp Tokamak and auxiliary systems is considerable, reaching 1100 MW during the plasma burn phase. If ºÚÁÏÉçapp were an industrial plant, the better part of that heat would be used to produce pressurized steam and (by way of turbines and generators) electricity. Only residual heat would need to be dissipated. But as an experimental installation, operating in pulses, ºÚÁÏÉçapp wasn't designed to produce electricity. All the power the fusion reaction generates will thus need to be extracted and rejected to the atmosphere. The cooling tower is made of 10 individual cells, each filled with a very thin plastic material. Water pumped to the top of the cells sprinkles through the filler. Large 12-metre fans at the top cells pull air through the filler to accelerate evaporation. And where an industrial power plant would deliver constant power output, the typical ºÚÁÏÉçapp operation cycle will consist of a succession of 500-second plasma pulses, each followed by 1300-second "dwell" period."The pulsed nature of ºÚÁÏÉçapp operation make it more challenging to make efficient use of the cooling tower," explains ºÚÁÏÉçapp Cooling Water Responsible Officer Steve Ployhar. "Among other things, it explains the need for two basins—hot water will be accumulated in the hot basin during the pulses and released to the cooling tower and cold basin during dwells." As civil works progress on the cooling water zone, fabrication of the 20-metre-high cooling tower is about to begin in India. Erection of the first two cooling tower cells is scheduled for completion in May 2018. 

Beryllium-tiled "fingers" from China—part of a semi-prototype of the ºÚÁÏÉçapp blanket first wall—have performed successfully under high heat flux testing at a dedicated facility in Russia. The test results confirm that the joining technique chosen for beryllium to copper bonding (i.e., hot isostatic pressing) has been shown to meet all ºÚÁÏÉçapp requirements. In ºÚÁÏÉçapp, 440 blanket modules will completely cover the inner walls of the vacuum vessel to shield its steel structure and protect other components from thermal and high-energy particle fluxes. Front-facing elements, called first wall panels, will take the brunt of the heat. Two different first wall panel designs are being pursued based on the incident heat flux—a normal heat flux first wall panel option (designed for 2 MW/m2) and an enhanced heat flux first wall panel option (designed for 4.7 MW/m2). A stainless steel beam (not shown in the picture) provides the structural base of each panel, upon which are attached plasma facing fingers. These fingers consist of 8-to-10-millimetre-thick beryllium armour tiles, bonded to a copper alloy heat sink, and attached to a stainless steel structural element.   China and Russia are sharing the procurement of the enhanced heat flux panels, while Europe is procuring the normal heat flux panels.   As part of the semi-prototype qualification program in China for its share of the enhanced heat flux first wall panels, pairs of "fingers" have undergone testing at the dedicated high heat flux test facility at the Efremov Institute in Saint Petersburg, Russia. They performed successfully at up to 4.7 MW/m2 for 7500 cycles and 5.9 MW/m2 for 1500 cycles. Neither unacceptable overheating nor temperature jump was observed during the test, and the appearance of the first wall fingers showed no significant alteration.    As per ºÚÁÏÉçapp technical requirements, the high heat flux testing was performed on actively cooled mockups of semi-prototypes. A screening test was carried out on three finger pairs at the start of the tests, during which the thermal load on the first wall surface was increased from 1 MW/m2 to 4.7 MW/m2 with steps of 1 MW/m2. Each increase in thermal load was made only after the finger pairs had reached temperature equilibrium. No anomaly was observed during the screening test.   A thermal fatigue test was then performed on two of these finger pairs over 7500 cycles at 4.7 MW/m2 and 1500 cycles at 5.9 MW/m2, each cycle consisting of 15 seconds of heating and 15 seconds of cooling. No unacceptable overheating of the two finger pairs was observed. Subsequent ultrasonic test results did not show defects on the beryllium to copper bonding, and there was no impact on the function and lifetime of the finger pairs. For the 5.9 MW/m2 test, a couple of hot spots were found that were within the boundaries of acceptability.   The Chinese Domestic Agency began its R&D effort on ºÚÁÏÉçapp enhanced heat flux first wall panels in 2004. The work (performed by the Southwestern Institute of Physics, SWIP) has progressed successfully as illustrated by the following achieved milestones: manufacture of high-purity beryllium, 2011; manufacture of small enhanced heat flux first wall mockups that passed high heat flux testing, 2013; optimization of mockups (including increasing the thickness of the beryllium tiles from 6 mm to 8 mm and successful thermal fatigue testing at 4.7MW/m2 over 16,000 cycles), July 2014.   These successful results open the way for the signature of the Procurement Arrangement, which is the precursor to series manufacturing.

Thirty-five metres long, five metres wide and five metres high, the two quench tanks that were unloaded last week at Fos harbour range among the largest components ever delivered to ºÚÁÏÉçapp. Manufactured in the Czech Republic under contract  with Air Liquide (the European Domestic Agency's supplier for the ºÚÁÏÉçapp liquid nitrogen plant and auxiliary systems), the twin tanks will be part of the ºÚÁÏÉçapp cryoplant. In case of a "quench"—the sudden loss of coil superconductivity—they will collect and store the helium that is expelled from the tokamak's magnetic system.   The tanks will leave Fos in the coming days and be ferried one at a time across the inland sea Etang de Berre by specially designed barge. They will travel along the ºÚÁÏÉçapp Itinerary as one convoy over three nights and are expected to reach the ºÚÁÏÉçapp site in the early hours of Thursday 24 November.

On 4-7 November, Director-General Bigot led a small ºÚÁÏÉçapp team to the Islamic Republic of Iran. The visit, conducted in response to Iran's formal request to be considered for participation in the ºÚÁÏÉçapp Project as an "Associate Member," was prepared with the full authorization of the existing ºÚÁÏÉçapp Members and was designed to improve ºÚÁÏÉçapp's understanding of Iran's fusion-related programs and related capacities. The agenda was densely packed. The ºÚÁÏÉçapp team visited each of Iran's small tokamak facilities and associated laboratories — at the Plasma Physics Research Center of Islamic Azad University, at the Atomic Energy Organization of Iran (AEOI), and at Amirkabir University of Technology — as well as a fifth small tokamak under construction. Particular attention was given to Iran's work on tokamak diagnostics, as a possible area of future collaboration.Understanding scientific and technological capacity also means understanding the humans involved: the fusion scientists, engineers, graduate and PhD students and post-docs who form the core of Iran's program. The ºÚÁÏÉçapp team presented the current status of the ºÚÁÏÉçapp Project, as well as selected ºÚÁÏÉçapp technologies, and listened to presentations by Iranian experts at all levels on their fusion-related research, experimentation, and technology development. This led to extensive Q&A sessions and animated sidebar discussions. Iran's keen interest in ºÚÁÏÉçapp was also evident in the participation of high-level government officials, whose commitment will be critical to any collaboration. Two members of the President's Cabinet — Vice President Ali Akbar Salehi, head of AEOI, and Vice President Sorena Sattari, who oversees science and technology — spent significant time with the group. Two documents also were signed, a Non-Disclosure Understanding and a Minutes of Meeting, to ensure mutual understanding of the purpose and conditions of the visit, and to signal the mutual intent of the ºÚÁÏÉçapp and the Islamic Republic of Iran to work in good faith toward a possible Cooperation Agreement. Iranian fusion experts from the Plasma Physics Research Center of Islamic Azad University explain the functioning and research program of the IR-T1 Tokamak. In many ways this was a historic moment. The ºÚÁÏÉçapp Agreement is open to any country that has the scientific, technological and financial commitment to contribute meaningfully to the project, towards the peaceful use of fusion technology in compliance with the Agreement. But such occasions have so far been rare in ºÚÁÏÉçapp's history.The next step will be for Director-General Bigot to discuss the results of his visit with the ºÚÁÏÉçapp Council. Ultimately, any decision related to a prospective new member or collaborator is strictly subject to the Council's unanimous approval. And any cooperation will need to be tightly woven into the already complex ºÚÁÏÉçapp schedule, in a way that promises mutual benefit for both Iran and ºÚÁÏÉçapp as the project builds toward the future. 

Less than one year ago, last December, the ºÚÁÏÉçapp signed a large supply contract with W. Schulz GmbH in Germany for the procurement of piping materials. The scope covers up to 65 km (1,800 tonnes) of pipes and 43,000 units (250 tonnes) of fittings.  The first shipment of pipes and fittings under this contract was delivered late October to the ºÚÁÏÉçapp worksite. It was the inaugural delivery of a broad ºÚÁÏÉçapp-Domestic Agency program for the centralized procurement of piping materials for the component (CCWS), chilled (CHWS), and tokamak cooling water systems, expected to play out over five years. Thirty-three tonnes of material were delivered, including 450 metres of stainless steel seamless pipes and 350 stainless steel fittings such as tees, elbows and reducers. The material will be stored in ºÚÁÏÉçapp's largest warehouse on site until needed for installation.  

Some of the most detailed images ever of a hot plasma inside a tokamak have been captured at MAST, the spherical tokamak device at the Culham Centre for Fusion Energy (CCFE) in the UK. At 100,000 frames per second, the movies from the MAST device give a vivid illustration of how tokamaks keep fusion fuel trapped in a magnetic cage, with particles moving around magnetic field lines and resembling a large spinning ball of wool. If only it were that simple; in reality, a magnetically-confined plasma is a highly complex system, and predicting how it behaves is key to making nuclear fusion a viable energy source. In particular, knowing how the hot fuel affects the cold walls of the machine is integral to ensuring that future reactors survive. Turbulence in the magnetic field throws out wispy bunches of particles—known as filaments—from the plasma in a seemingly random fashion, ejecting fuel which touches the surfaces of the tokamak. Researchers are now working to unravel meaning within this randomness to understand this complex interaction with the machine walls, and videos such as these can give them pointers to what is happening. Nick Walkden of CCFE's Theory & Modelling Department, who produced the videos, explains: "We believe that filaments are a vital part of the 'exhaust process' within a tokamak—how particles are expelled from the plasma. Seeing the MAST plasma at this unprecedented level of detail enables us to image individual filaments and measure their size, velocity and position within the plasma. It tells us a lot about their physics so we can find out how to predict their motion and, in future experiments, possibly learn to control them." Read the full article at CCFE. 

Physicist Richard Hawryluk of the Princeton Plasma Physics Laboratory (PPPL) has been named chair of the board of editors of Nuclear Fusion. Current head of the ºÚÁÏÉçapp and Tokamaks Department at PPPL and former Deputy Director-General of Administration at ºÚÁÏÉçapp, Hawryluk has been a member of the editorial board at Nuclear Fusion since 2009. In his new role as chair he will provide policy oversight and support to the journal's editor. From 1991 to 1997 he headed the Tokamak Fusion Test Reactor (TFTR) project, the only magnetic confinement fusion experiment in the US to have operated on a high-power mix of deuterium and tritium. He was also deputy director of PPPL lab from 1997 to 2009, before taking over the running of the ºÚÁÏÉçapp and Tokamaks Department.