Residual carbon content in the initial ITER-Like Wall experiments at JET
2013 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 438, no Suppl., S303-S308 p.Article in journal (Refereed) Published
The residual carbon content and carbon edge flux in JET have been assessed by three independent diagnostic techniques after start of plasma operation with the ITER-Like Wall (ILW) with beryllium first wall and tungsten divertor: (i) in-situ measurements with optical spectroscopy on low ionisation stages of carbon, (ii) charge-exchange recombination spectroscopy, and (iii) residual gas composition analysis in dedicated global gas balance experiments. Direct comparison experiments in L-mode discharges were carried out between references from the previously installed material configuration with plasma-facing components made of carbon-fibre composite (JET-CFC) and the JET-ILW. The temporal evolution of the C divertor flux since installation of the ILW has been studied in the ohmic phase of dedicated monitoring discharges which have been executed regularly throughout the experimental exploitation so far (60000 plasma seconds). The C flux behaviour in the divertor can be divided in three phases: initial fast drop, moderate reduction phase, and a long lasting phase with almost constant C flux. The Be flux in both divertor legs mirrors the behaviour of C. All experiments and diagnostic techniques demonstrate a strong reduction in C fluxes and C content of more than one order of magnitude with respect to JET-CFC which is in line with the reduction in long-term fuel retention due to co-deposition. There is no evidence of an increase in residual carbon in time, thus no indication that a damage of the thin tungsten coatings on CFC substrate in the divertor occurred.
Place, publisher, year, edition, pages
2013. Vol. 438, no Suppl., S303-S308 p.
Carbon-fibre composite, Charge-exchange recombination spectroscopies, Diagnostic techniques, In-situ measurement, Material configurations, Optical spectroscopy, Plasma-facing components, Residual gas composition, Electric discharges, Experiments, Plasmas, Tokamak devices, Tungsten, Carbon
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-140091DOI: 10.1016/j.jnucmat.2013.01.122ISI: 000330795300056ScopusID: 2-s2.0-84885468188OAI: oai:DiVA.org:kth-140091DiVA: diva2:689058
20th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI), Forschungszentrum Julich, Aachen, Germany, May 21-25, 2012
QC 201401202014-01-202014-01-172014-03-06Bibliographically approved