Deuterium inventory determination in beryllium and mixed beryllium-carbon layers doped with oxygen

Nemanič, Vincenc; Žumer, Marko; Poroşnicu, C.; Butoi, Bogdan; Alves, E.; Mateus, R.

doi:10.1016/j.fusengdes.2019.111365

Cited by 4 publications

(3 citation statements)

References 21 publications

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“…BeD 2 was observed in plasma-exposed samples using a surface technique, X-ray Photoelectron Spectroscopy (XPS) in 2009 [11] but, to our knowledge, there was no further direct observation since then, except when we reported on the growth of crystalline BeD 2 , coexisting with blisters, at an implantation fluence of about 1×10 21 D m −2 , close to the saturation value [12]. It should be noted that the presence of impurities most probably play a role in the shape of TDS spectra, especially in the case of JET samples [13,14].…”

Section: Introductionmentioning

confidence: 76%

D retention and material defects probed using Raman microscopy in JET limiter samples and beryllium-based synthesized samples

Pardanaud¹,

Kumar²,

Roubin³

et al. 2021

Phys. Scr.

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We report on the detection by means of Raman spectroscopy of amorphous beryllium deuteride, BeD2, in magnetron sputtered deposits synthesized in two different laboratories and containing about 20 at% of deuterium. In contrast, this signature has not been found for the JET limiter samples studied coming from the inner, outer or upper limiters, even when coming from a deposition zone of the limiters. We give a way to disentangle that BeD2 signature from other signatures falling in the same spectroscopic range and mainly related to other phenomena. We also analyze the Raman characteristics of the JET sample defects. These results could help in the interpretation of D thermal desorption spectra and in future analyses of JET thick Be deposit divertor tiles.

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Section: Introductionmentioning

confidence: 76%

D retention and material defects probed using Raman microscopy in JET limiter samples and beryllium-based synthesized samples

Pardanaud¹,

Kumar²,

Roubin³

et al. 2021

Phys. Scr.

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“…For tritium, main concerns associated with deposition layer formation are complicated desorption of tritium already accumulated. ITER bake-out temperature is planned to be 510 K, which might be enough for beryllium materials, but the desorbed deuterium and tritium might still be retained in the carbon deposit layer [41,42].…”

Section: Effects Of Deposition Layer On Tritium Retentionmentioning

confidence: 99%

Tritium in plasma-facing components of JET with the ITER-Like-Wall

et al. 2021

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The ITER-Like-Wall project has been carried out at the Joint European Torus (JET) to test plasma facing materials relevant to ITER. Materials being tested include both bulk metals (Be and W) and coatings. Tritium accumulation mechanisms and release properties depend both on the wall components, their location in the vacuum vessel, conditions of exposure to plasma and to the material itself. In this study, bulk beryllium limiter tiles, plasma-facing beryllium coated Inconel components from the main chamber, bulk tungsten and tungsten coated carbon fibre composite divertor tiles were analysed. A range of methods have been developed and applied in order to obtain a comprehensive overview on tritium retention and behaviour in different materials of plasma facing components (PFCs). Tritium content and chemical state were studied by the means of chemical or electrochemical dissolution methods and thermal desorption spectroscopy. Tritium distribution in the vacuum vessel and factors affecting its accumulation have been assessed and discussed.

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“…For the ultimate benchmarking of CF-LIBS application for ITER, Be-deposits themselves are indispensable, which are produced with D or He content included [9]. CF-LIBS measurements were carried out in the Be compatible facilities at the VTT Technical Research Centre of Finland.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of tritium and impurities in the first wall of fusion devices using a LIBS based diagnostic

Meiden¹,

Almaviva²,

Butikova³

et al. 2021

Nucl. Fusion

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Laser-induced breakdown spectroscopy (LIBS) is one of the most promising methods for quantitative in-situ determination of fuel retention in plasma-facing components (PFCs) of magnetically confined fusion devices like ITER and JET. In this article, the current state of understanding in LIBS development for fusion applications will be presented, based on a complete review of existing results and complemented with newly obtained data. The work has been performed as part of a research programme, set up in the EUROfusion Consortium, to address the main requirements for ITER: (a) quantification of fuel from relevant surfaces with high sensitivity, (b) the technical demonstration to perform LIBS with a remote handling system and (c) accurate detection of fuel at ambient pressures relevant for ITER. For the first goal, the elemental composition of ITER-like deposits and proxies to them, including deuterium (D) or helium (He) containing W–Be, W, W–Al and Be–O–C coatings, was successfully determined with a typical depth resolution ranging from 50 up to 250 nm per laser pulse. Deuterium was used as a substitute for tritium (T) and in the LIBS experiments deuterium surface densities below 1016 D/cm2 could be measured with an accuracy of ∼30%, confirming the required high sensitivity for fuel-retention investigations. The performance of different LIBS configurations was explored, comprising LIBS systems based on single pulse (pulse durations: ps–ns) and double pulse lasers with different pulse durations. For the second goal, a remote handling application was demonstrated inside the Frascati-Tokamak-Upgrade (FTU), where a compact, remotely controlled LIBS system was mounted on a multipurpose deployer providing an in-vessel retention monitor system. During a shutdown phase, LIBS was performed at atmospheric pressure, for measuring the composition and fuel content of different area of the stainless-steel FTU first wall, and the titanium zirconium molybdenum alloy tiles of the toroidal limiter. These achievements underline the capability of a LIBS-based retention monitor, which complies with the requirements for JET and ITER operating in DT with a beryllium wall and a tungsten divertor. Concerning the capabilities of LIBS at pressure conditions relevant for ITER, quantitative determination of the composition of PFC materials at ambient pressures up to 100 mbar of N2, the D content could be determined with an accuracy of 25%, while for atmospheric pressure conditions, an accuracy of about 50% was found when using single-pulse lasers. To improve the LIBS performance in atmospheric pressure conditions, a novel approach is proposed for quantitative determination of the retained T and the D/T ratio. This scenario is based on measuring the LIBS plume emission at two different time delays after each laser pulse. On virtue of application of a double pulse LIBS system, for LIBS application at N2 atmospheric pressure the distinguishability of the spectra from H isotopes could be significantly improved, but further systematic research is required.

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Deuterium inventory determination in beryllium and mixed beryllium-carbon layers doped with oxygen

Cited by 4 publications

References 21 publications

D retention and material defects probed using Raman microscopy in JET limiter samples and beryllium-based synthesized samples

D retention and material defects probed using Raman microscopy in JET limiter samples and beryllium-based synthesized samples

Tritium in plasma-facing components of JET with the ITER-Like-Wall

Monitoring of tritium and impurities in the first wall of fusion devices using a LIBS based diagnostic

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