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![]() The ITER-Monaco Fellows. At the Post-Doctoral Seminar on 23 July, the Fellows were invited by ITER Director-General Kaname Ikeda, and ITER Principal Deputy Director-General Norbert Holtkamp to present the state of their work. "You have been at ITER since the beginning of the year," said Director-General Ikeda in his opening remarks. "Many of us — at ITER and also on the outside — would like to know how you are enjoying your stay, and how your work is progressing." American Matthew Jewell focuses his research on the quality analysis and control of niobium-tin (Nb3Sn) superconducting strands. 500 tons of these strands will be procured for ITER through nine suppliers on three continents. Using a database to keep track of the properties of each unit length of strand — from raw materials right up to the finished product — is an important part of Matt's work at ITER. ![]() Matthew Jewell and Sophie Carpentier. Inside the ITER Tokamak, where plasma at millions of degrees Celsius will be only centimetres from material surfaces, some of the tritium fuel will be 'captured' by the first wall during operation. Sophie Carpentier, from France, uses physics modelling to provide estimates for this quantity of retained tritium - an important part of meeting nuclear regulations that stipulate the maximum amount of tritium allowable in the vacuum chamber at any one time. Sophie and her colleagues are refining rather crude previous estimates, using and improving upon existing modelling tools. "We aim to develop a picture of the global erosion/redeposition pattern on each blanket shield module within the vacuum vessel in order to provide the best estimates of expected tritium retention before deuterium-tritium operation." ![]() Axel Winter, Junghee Kim and Evgeny Veshchev. Like Sophie, Junghee Kim from Korea is interested in tritium retention, as well as in erosion of divertor surfaces and the creation of 'dust' during operation. He is studying the best diagnostic tools for the measurement of these parameters, which will require close monitoring during ITER operation for safety and optimum plasma performance. Measurement requirements have been established for the different systems and candidate diagnostic tools have been identified; Junghee is participating in their evaluation. "By studying competitive techniques, monitoring experimental and theoretical activities and evaluating potential hazards, we are on our way to identifying the most promising diagnostics for ITER to monitor divertor erosion, dust production and tritium retention arising from plasma operation," explains Junghee. "Once chosen, we will integrate the diagnostic system into the design of ITER in the most optimum way." The physics of energetic plasma ions is the research focus for Evgeny Veshchev from the Russian Federation. It is an important field of study since effective plasma heating and good fast ion confinement are essential for ignition. When fusion-born alpha particles escape from the plasma, they are responsible for energy loss and can also cause first wall damage within the Tokamak. Evgeny is working with theoretical predictions as well as simulation results for this phenomenon in order to identify new diagnostic techniques and alternative candidates for lost alpha measurements. "Fusion alpha particles should transfer their energy to the plasma," explains Evgeny, "however some losses are foreseen. Our research work will contribute to the optimization of plasma discharge scenarios and the protection of the machine." << return to Newsline #92 |
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