Deposition in the inner and outer corners of the JET divertor with carbon wall and metallic ITER-like wall

Beal, J.; Widdowson, A.; Heinola, K.; Baron-Wiechec, A.; Gibson, K.J.; Coad, J. P.; Alves, E.; Lipschultz, B.; Kirschner, A.; Esser, H. G.; Matthews, G. F.; Brezinsek, S.; Contributors, Jet

doi:10.1088/0031-8949/t167/1/014052

Cited by 14 publications

(7 citation statements)

References 18 publications

(20 reference statements)

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“…The 12C( 3 He,p0)14N and 12 C( 3 He,p1) 14 N reactions were used to measure the C content [15]. The 9 Be( 3 He,p0) 11 B and 9 Be( 3 He,p1) 11 B reactions were used to measure the Be content [16]. In both JET-ILW1 and JET-ILW2 for which data from tile 5 is available, the strongest erosion was observed there, in the areas close to the maximum duration of strike-point positioning.…”

Section: Ion Beam Analysismentioning

confidence: 99%

“…In 2010, the plasma-facing components of JET were changed from full carbon to the ITER-like wall (JET-ILW) configuration, comprising of Be tiles in the main chamber and carbon tiles coated with thick (~20 μm) W layers in the divertor [4] with a bulk W central divertor tile [5]. The JET-ILW was shown to affect the erosion-deposition patterns [6][7][8][9] and fuel retention [10] as compared to the previous full carbon device.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of erosion and deposition in JET divertor during the first three ITER-like wall campaigns

et al. 2020

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The manuscript presents an overview of the erosion and deposition data in the inner and outer JET divertor observed during the first three ITER-like wall campaigns (JET-ILW1, JET-ILW2, JET-ILW3). Erosion and deposition were studied using core samples cut out from divertor tiles. For the studied samples a similar general deposition pattern was observed in all three campaigns: More than 60% of the total deposition occurred in the upper region of the inner divertor on tiles 0 and 1, where Be was transported and deposited from the scrape-off layer (SOL). High erosion was observed only on tile 5. In JET-ILW2 and 3, erosion together with high power fluxes was observed in the outer divertor at the bottom of tile 7. Additionally, deposition peaks were observed on the sloping parts of tiles 4 and 6, which were more pronounced in JET-ILW2 and 3 due to placing the strike point more often on these tiles. The deposits consisted primarily of Be, with some additional D and C. Deposition rates were observed to decrease from campaign to campaign, with the C deposition rate decreasing the most, more than 2 times from JET-ILW1 to JET-ILW3. D retention up to levels of ~1 at. % was observed up to large depths in the W protective coatings in all campaigns.

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Section: Ion Beam Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of erosion and deposition in JET divertor during the first three ITER-like wall campaigns

et al. 2020

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“…The energy flux to the outer divertor corner is significantly greater than to the inner corner, and surface temperatures are probably higher as a result. The deposition monitor data shows a greater impurity flux to the outer corner [9], as do the rotating collectors [17]. As an indication of the extent of primary erosion of the incoming flux, the outer monitor indicated a flux of Be of 17.5 × 10 18 atoms cm -2 over the ILW1 campaign, yet the lower.…”

Section: Introductionmentioning

confidence: 92%

Impurity re-distribution in the corner regions of the JET divertor

et al. 2017

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The International Thermonuclear Experimental Reactor (ITER) will use a mixture of deuterium (D) and tritium (T) as the fuel to generate power. Since T is both radioactive and expensive the Joint European Torus (JET) has been at the forefront of research to discover how much T is used and where it may be retained within the main reaction chamber. Until the year 2010 the JET plasma facing components were constructed of carbon fibre composites (CFC). During the JET carbon (C) phases impurities accumulated at the corners of the divertor located towards the bottom of the chamber in regions shadowed from the plasma where they are very difficult to reach and remove. This build-up of C and the associated H-isotope (including T) retention were of particular concern for future fusion reactors therefore, in 2010 JET changed the wall protection to (mainly) Be and the divertor to tungsten (W)-the JET ITER-like Wall (ILW)-the choice of materials for ITER. This paper reveals that with the JET ILW impurities are still accumulating in the shadowed regions, with Be being the majority element, though the overall quantities are very much reduced from those in the C phases. The strike points for corner discharges are the principle source of the material transporting into the shadowed regions, but particles typically have about a 75% probability of reflection from lineof sight surfaces, and multiple reflection/scattering results in deposition over all surfaces.

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“…As a result, eroded Be atoms mostly remain in the area where they were first re-deposited from the SOL. However, despite that fact, some quantities of beryllium reach shadowed regions in the divertor, as detected in studies of wall probes located in the divertor: test mirrors and [129][130][131], spatial blocks [132], rotating collectors [133][134][135], louvre clips [136] and covers of quartz microbalance [121,132].…”

Section: Materials Migration and Fuel Retentionmentioning

confidence: 99%

Overview of JET results for optimising ITER operation

et al. 2022

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The JET 2019-2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major Neutral Beam Injection (NBI) upgrade providing record power in 2019-2020, and tested the technical & procedural preparation for safe operation with tritium. Research along three complementary axes yielded a wealth of new results. Firstly, the JET plasma programme delivered scenarios suitable for high fusion power and alpha particle physics in the coming D-T campaign (DTE2), with record sustained neutron rates, as well as plasmas for clarifying the impact of isotope mass on plasma core, edge and plasma-wall interactions, and for ITER pre-fusion power operation. The efficacy of the newly installed Shattered Pellet Injector for mitigating disruption forces and runaway electrons was demonstrated. Secondly, research on the consequences of long-term exposure to JET-ILW plasma was completed, with emphasis on wall damage and fuel retention, and with analyses of wall materials and dust particles that will help validate assumptions and codes for design & operation of ITER and DEMO. Thirdly, the nuclear technology programme aiming to deliver maximum technological return from operations in D, T and D-T benefited from the highest D-D neutron yield in years, securing results for validating radiation transport and activation codes, and nuclear data for ITER.

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Deposition in the inner and outer corners of the JET divertor with carbon wall and metallic ITER-like wall

Cited by 14 publications

References 18 publications

Comparison of erosion and deposition in JET divertor during the first three ITER-like wall campaigns

Comparison of erosion and deposition in JET divertor during the first three ITER-like wall campaigns

Impurity re-distribution in the corner regions of the JET divertor

Overview of JET results for optimising ITER operation

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