Mechanical and thermo-physical characterization of three-directional carbon fiber composites for W-7X and ITER

Pintsuk, G.; Compan, J.; Koppitz, T.; Linke, J.; Peacock, Alan T.; Pitzer, D.; Rödig, M.; Wikman, Stefan

doi:10.1016/j.fusengdes.2008.11.062

Cited by 12 publications

(5 citation statements)

References 13 publications

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“…By combining with the ablation rates of the different layers measured in section 5.2, for the first time, the absolute erosion/deposition amount patterns of C and Mo for the centre scan line (figure 12(e)) at the vertical target element TM2v2 in OP1.2A were mapped in figure 15 by ps-LIBS technique. In these calculations, the used densities of C and Mo are 1.8 g cm −3 [35,36] As shown in figure 15(a), only very little deposition of C and Mo are observed from s = 2 mm to about s = 52 mm in the poloidal direction in remote areas due to the little plasma impact. A relatively wide net erosion zone with a poloidal extension from s = 75 mm to s = 270 mm was observed.…”

Section: Quantitative Analysis Of Erosion/deposition Patternsmentioning

confidence: 99%

Quantification of erosion pattern using picosecond-LIBS on a vertical divertor target element exposed in W7-X

De-you¹,

Yi²,

Eksaeva³

et al. 2020

Nucl. Fusion

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A set of dedicated marker samples consisting of fine-grain graphite as substrate, an interlayer of 0.2–0.4 μm molybdenum (Mo) employed as marker, and a 5–10 μm thick carbon (C) marker layer on top were installed in Wendelstein 7-X (W7-X) to investigate locally the C erosion and deposition. In this study, a set of five individual marker tiles, installed in a vertical divertor element of the test divertor unit in half-module 50, and exposed to about 40 min of plasma predominant in the standard magnetic divertor configuration in the first year of divertor operation in W7-X (OP1.2A), were retrieved from the vessel for post-mortem analysis. Picosecond laser induced breakdown spectroscopy (ps-LIBS) was applied on these marker tiles in order to determine the local erosion/deposition pattern caused by plasma impact. The general erosion/deposition pattern on the vertical target element was studied with the aid of depth-profiling by Mo line emission due to ps-LIBS with the number of applied laser pulses (355 nm, 2.3 J cm−2, 35 ps) at one probing location. Several potential asymmetry factors which avoid a perfect layer-by-layer ablation process in the laser ablations are proposed and discussed when a rough layered structure sample with a rough surface is analysed by the ps-LIBS technique. Thereby, a simulation model was developed to correct the measurement error of the ps-LIBS method caused by the non-perfect rectangle profile of the applied laser beam. The depth resolution of the applied ps-LIBS system was determined by quantification of the laser ablation rates of the different layers and the C substrate which were measured utilising profilometry and cross comparison with the thicknesses of the C and Mo marker layers determined by a combined focused ion beam and scanning electron microscopy technique. For the first time, the erosion/deposition pattern on the vertical target was mapped and quantified by ps-LIBS technique. A relatively wide net erosion zone with a poloidal extend of about 200 mm was identified which can be correlated to the main particle interaction zone at the magnetic strike-line of the dominantly applied standard magnetic divertor configuration. At the position of peak erosion, not only 7.6 × 1019 C atoms/cm2 but also 2 × 1018 Mo atoms/cm2 which results can be extrapolated to total 15 × 1019 C atoms/cm2, were eroded due to plasma fuel particle (H, He) and impurity (O, C) ion impact.

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Section: Quantitative Analysis Of Erosion/deposition Patternsmentioning

confidence: 99%

Quantification of erosion pattern using picosecond-LIBS on a vertical divertor target element exposed in W7-X

De-you¹,

Yi²,

Eksaeva³

et al. 2020

Nucl. Fusion

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“…Active Metal Casting, was selected and to improve its reliability, the CFC N11 used for Tore Supra was replaced by the CFC NB31, which has better mechanical properties. Developed during EFDA R&D activities, this grade was the reference material for the ITER divertor at that time, presently replaced by CFC NB41 [8]. This decision was also supported by the results of the different high heat flux testing of prototypes validating the compatibility of this material with the AMC technology [9].…”

Section: Summary Of Randd Activitiesmentioning

confidence: 96%

Summary of Research and Development Activities for the Production of the Divertor Target Elements of Wendelstein 7-X

Boscary

Peacock

Smirnow

et al. 2014

IEEE Trans. Plasma Sci.

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Abstract-The realization of the high heat flux divertor of the stellarator Wendelstein 7-X requires the production of 890 target elements. Since the divertor has to operate for 30 minutes with an input cw plasma power of 10 MW, the target elements need to be actively water-cooled. A target element is made of a CuCrZr copper alloy heat sink armored with CFC NB31 tiles. It is designed to remove a stationary heat flux of 10 MW/m² on its main area and 5 MW/m² at the end adjacent to the pumping gap. R&D activities proved to be essential for the preparation and the support of the on-going serial fabrication. The most critical issue is the stable production of the bonding between the CFC tiles and the heat sink as the divertor surface consists of about 16,000 tiles. The fast unexpected failure of one tile may reduce the whole divertor performance and, consequently, restrict the stationary machine operation. Two main R&D phases allow the design improvements of the target elements compatible with industrial and economic constrains of the series production as well as the development of quality controls such as a visual inspection system able to easily detect and fast record cracks at the interface between CFC tiles and heat sink.

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“…7), whilst z-axis turns out to be out-of-plane. For the fiber reinforced ceramic phase, parameters governing the elastic-plastic anisotropic response at low strains (see Table 1) are derived from the comprehensive handbook on ITER Materials [22] and adapted to the present formulation, when required integrated by literature data [23,24]. As well-known, the remaining ratios appearing in the compliance matrix Eq.…”

Section: Heterogeneous Model Of the Joined Samplementioning

confidence: 99%

Characterization of innovative CFC/Cu joints by full-field measurements and finite elements

Fedele

Ciani

Galantucci

et al. 2014

Materials Science and Engineering: A

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Mechanical and thermo-physical characterization of three-directional carbon fiber composites for W-7X and ITER

Cited by 12 publications

References 13 publications

Quantification of erosion pattern using picosecond-LIBS on a vertical divertor target element exposed in W7-X

Quantification of erosion pattern using picosecond-LIBS on a vertical divertor target element exposed in W7-X

Summary of Research and Development Activities for the Production of the Divertor Target Elements of Wendelstein 7-X

Characterization of innovative CFC/Cu joints by full-field measurements and finite elements

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