Novello, L.*; Cara, P.*; Coletti, A.*; Gaio, E.*; Maistrello, A.*; Matsukawa, Makoto; Philipps, G.*; Tomarchio, V.*; Yamauchi, Kunihito
IEEE Transactions on Applied Superconductivity, 26(2), p.4700507_1 - 4700507_7, 2016/03
Loarte, A.*; Lipschultz, B.*; Kukushkin, A. S.*; Matthews, G. F.*; Stangeby, P. C.*; Asakura, Nobuyuki; Counsell, G. F.*; Federici, G.*; Kallenbach, A.*; Krieger, K.*; et al.
Nuclear Fusion, 47(6), p.S203 - S263, 2007/06
Progress, since the ITER Physics Basis publication (1999), in understanding the processes that will determine the properties of the plasma edge and its interaction with material elements in ITER is described. Significant progress in experiment area: energy and particle transport, the interaction of plasmas with the main chamber material elements, ELM energy deposition on material elements and the transport mechanism, the physics of plasma detachment and neutral dynamics, the erosion of low and high Z materials, their transport to the core plasma and their migration at the plasma edge, retention of tritium in fusion devices and removal methods. This progress has been accompanied by the development of modelling tools for the physical processes at the edge plasma and plasma-materials interaction. The implications for the expected performance in ITER and the lifetime of the plasma facing materials are discussed.
Lipschultz, B.*; Asakura, Nobuyuki; Bonnin, X.*; Coster, D. P.*; Counsell, G.*; Doerner, R.*; Dux, R.*; Federici, G.*; Fenstermacher, M. E.*; Fundamenski, W.*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
The work of the ITPA SOL/divertor group is reviewed. The high-n nature of ELMs has been elucidated and new measurements have determined that they carry 10-20% of the ELM energy to the far SOL with implications for ITER limiters and the upper divertor. Analysis of ELM measurements imply that the ELM continuously loses energy as it travels across the SOL. The prediction of ITER divertor disruption power loads have been reduced as a result of finding that the divertor footprint broadens during the thermal quench and that the plasma can lose up to 80% of its thermal energy before the thermal quench (not for VDEs or ITBs). Disruption mitigation through massive gas puffing has been successful at reducing divertor heat loads but estimates of the effect on the main chamber walls indicate 10s of kG of Be would be melted/mitigation. Long-pulse studies have shown that the fraction of injected gas that can be recovered after a discharge decreases with discharge length. The use of mixed materials gives rise to a number of potential processes.
Roth, J.*; Kirschner, A.*; Bohmeyer, W.*; Brezinsek, S.*; Cambe, A.*; Casarotto, E.*; Doerner, R.*; Gauthier, E.*; Federici, G.*; Higashijima, Satoru; et al.
Journal of Nuclear Materials, 337-339, p.970 - 974, 2005/03
In the frame work of the EU Task Force on Plasma-Wall Interaction and the International Tokamak Physics Activity an attempt was made to establish a possible dependence of the chemical erosion yield of carbon on the ion flux, , involving ion beam experiments, plasma simulators, and fusion devices. After data normalization a fit using Bayesian probability analysis was performed yielding a decrease of the erosion yield with at high ion fluxes. With this dependence on ion flux a comprehensive description is available for chemical erosion as function of energy, temperature and ion flux. Using this dependence the erosion and redeposition of carbon in the ITER divertor can be calculated using the ERO code and the steady-state plasma scenario given by the ITER team. The resulting gross and net erosion rates are compared to previous estimates using a constant erosion yield of 1.5%. The use of the complete parameter dependence results in an order of magnitude lower erosion, most strongly determined by the temperature dependence and the reduction at the highest fluxes.
Roth, J.*; Preuss, R.*; Bohmeyer, W.*; Brezinsek, S.*; Cambe, A.*; Casarotto, E.*; Doerner, R.*; Gauthier, E.*; Federici, G.*; Higashijima, Satoru; et al.
Nuclear Fusion, 44(11), p.L21 - L25, 2004/11
Chemical erosion of carbon has been studied in ion beam experiments, and the yield values are available as a function of ion energy and surface temperature. ITER divertor condition, however, cannot be simulated by ion beam. For extrapolating to ITER, the erosion must be investigated in plasma simulators and in SOL or divertors of present fusion devices. In the past, erosion values were reported, but the values showed a wide scatter as a function of ion flux, . Therefore, a joint attempt was made through the EU Task Force on Plasma-Wall Interaction and the International Tokamak Physics Activity (ITPA) to clarify the flux dependence. For each data point the local plasma conditions were normalized to impact energy of 30 eV, the data were selected for a surface temperature close to the maximum yield or to room temperature, and the diagnostic was calibrated in-situ. Through this procedure, the previous large scatter could be drastically reduced. A fit using Bayesian probability analysis was performed yielding a decrease of the erosion yield with at high ion fluxes.
Asakura, Nobuyuki; Loarte, A.*; Porter, G.*; Philipps, V.*; Lipschultz, B.*; Kallenbach, A.*; Matthews, G.*; Federici, G.*; Kukushkin, A.*; Mahdavi, A.*; et al.
IAEA-CN-94/CT/P-01, 5 Pages, 2002/00
Three important physics issues for the ITER divertor design and operation are summarized based on the experimental and numerical work from multi-machine database (JET, JT-60U, ASDEX Upgrade, DIII-D, Alcator C-Mod and TEXTOR). (i) The energy load associated with Type-I ELMs is of great concern for the lifetime of the ITER divertor target. In order to understand the physics base of the scaling models, the ELM heat and particle transport to the divertor is investigated. Convective transport during ELMs plays an important role in heat transport to the divertor. (ii) Determination of the SOL flow pattern and the driving mechanism has progressed experimentally and numerically. Influences of the drift effects on the SOL and divertor plasma transport were discussed. (iii) Characteristics of chemical yield at two different deposited carbon surfaces, i.e. erosion- and redeposition-dominated areas, have been studied. Progress of understanding the chemical erosion is reviewed.
Kasugai, Atsushi; Bazin, N.*; Cara, P.*; Chel, S.*; Gex, D.*; Heidinger, R.*; Yoshida, Kiyoshi; Ihara, Akira; Knaster, J.*; Kondo, Keitaro; et al.
no journal, ,
The International Fusion Materials Irradiation Facility (IFMIF) aims to provide an accelerator-based, D-Li neutron source to produce high energy neutrons at sufficient intensity and irradiation volume for DEMO reactor materials qualification. The IFMIF/EVEDA project, which is part of the Broader Approach (BA) agreement between Japan and EU, has the mission to work on the engineering design of IFMIF and to validate the main technological challenges. The prototype accelerator being developed in the IFMIF-EVEDA project consists of an injector, a RFQ accelerator, and a part of superconducting Linac. The design of the cryoplant for SRF-linac has been already completed and it will be started to install to the facility from coming September after the licensing. This article describes the cryoplant for the IFMIF/EVEDA prototype accelerator facility.