Main chamber wall plasma loads in JET-ITER-like wall at high radiated fraction

Guillemaut, C.; Drewelow, P.; Matthews, G. F.; Kukushkin, A.S.; Pitts, R.A.; Abreu, P.; Brezinsek, S.; Brix, M.; Carman, P.; Coelho, R.; Devaux, S.; Flanagan, J.; Giroud, C.; Harting, D.; Lowry, C.; Maggi, C. F.; Militello, F.; Thun, C. Perez von; Solano, E.R.; Widdowson, A.; Wiesen, S.; Wischmeier, M.; Wood, David; Contributors, Jet

doi:10.1016/j.nme.2017.02.010

Cited by 7 publications

(9 citation statements)

References 20 publications

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“…The low maximum value of f rad even under completely detached conditions indicates a discrepancy in the power balance at JET which is currently under investigation [17,18]. In the zoomed part of Fig.…”

Section: Characterisation Of Neon Seeded Jet Dischargesmentioning

confidence: 94%

“…With a maximum radiative power fraction of f rad,max,Ne = 0.66 the discharges remained slightly below the JET maximum of f rad,max,JET = 0.75, which has been achieved with nitrogen seeding under completely detached conditions [10]. The low maximum value of f rad even under completely detached conditions indicates a discrepancy in the power balance at JET which is currently under investigation [17,18]. In the zoomed part of figure 2 the poloidal positions of the divertor Langmuir probes (LPs, red) are shown.…”

Section: Characterisation Of Neon Seeded Jet Dischargesmentioning

confidence: 98%

“…By increasing the neon puff, only minor increases in radiation can be achieved. The low f rad even with completely detached targets are yet to determine [17,18].…”

Section: Influence Of the Neon Puff On The L-h Transitionmentioning

confidence: 99%

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Characterisation of highly radiating neon seeded plasmas in JET-ILW

et al. 2019

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To study the impact of strong impurity radiation on the energy confinement and the discharge stability, at JET-ILW dedicated high-density, highly heated experiments with neon seeding have been performed. In these experiments an increase of radiation in the core and especially the pedestal region and a characteristic strong X-point radiator inside the confined region have been observed. The increased radiation inside the separatrix had no impact on the energy confinement. Only at the highest neon puff rates and highest heating powers (29 MW) a weak H-mode without back-transitions to L-mode (M-mode) could be achieved, while at lower heating powers or seeding levels L-modes and oscillations between H-mode and L-mode could be observed. In H-mode, at highest neon seeding levels the targets are in complete detachment. A degradation of the pedestal density profile was observed when neon was seeded. A correlation between this density pedestal degradation, the appearance of an X-point radiator and the detachment of the targets was found in neon seeded H-mode pulses.In ASTRA-TGLF core transport simulations it could be shown that the increase of the electron temperature in the core with neon seeding is attributed to a partial stabilisation of ITG modes.

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Section: Characterisation Of Neon Seeded Jet Dischargesmentioning

confidence: 94%

Section: Characterisation Of Neon Seeded Jet Dischargesmentioning

confidence: 98%

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Characterisation of highly radiating neon seeded plasmas in JET-ILW

et al. 2019

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“…The temperatures of the plasma facing surfaces are monitored by IR imaging [15] (more recent pub?) and subsurface thermocouples [16].…”

Section: Experiments Strategymentioning

confidence: 99%

Isotope removal experiment in JET-ILW in view of T-removal after the 2nd DT campaign at JET

Wauters¹,

Matveev²,

Douai³

et al. 2022

Phys. Scr.

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A sequence of fuel recovery methods was tested in JET, equipped with the ITER-like beryllium main chamber wall and tungsten divertor, to reduce the plasma deuterium concentration to less than 1% in preparation for operation with tritium. This was also a key activity with regard to refining the clean-up strategy to be implemented at the end of the 2nd DT campaign in JET (DTE2) and to assess the tools that are envisaged to mitigate the tritium inventory build-up in ITER. The sequence began with 4 days of main chamber baking at 320ºC, followed by a further 4 days in which Ion Cyclotron Wall Conditioning (ICWC) and Glow Discharge Conditioning (GDC) were applied with hydrogen fuelling, still at 320ºC, followed by more ICWC while the vessel cooled gradually from 320ºC to 225ºC on the 4th day. While baking alone is very efficient at recovering fuel from the main chamber, the ICWC and GDC sessions at 320ºC still removed slightly higher amounts of fuel than found previously in isotopic changeover experiments at 200ºC in JET. Finally, GDC and ICWC are found to have similar removal efficiency per unit of discharge energy. Raising the inner divertor strike point up to the uppermost accessible point allowed local heating of the surfaces to at least 800ºC for the duration of this discharge configuration (typically 18 s), according to infra-red thermography measurements. In laboratory thermal desorption measurements, maintaining this temperature level for several minutes depletes thick co-deposit samples of fuel. The fuel removal by 14 diverted plasma discharges is analysed, of which 9, for 160 s in total, with raised inner strike point. The initial D content in these discharges started at the low value of 3-5%, due to the preceding baking and conditioning sequence, and reduced further to 1%, depending on the applied configuration, thus meeting the experimental target.

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“…Therefore, the first objective of the present work is to find an experimental answer to the general question 'how much energy do filaments transport?'. Also, since particle transport towards the first wall is substantially enhanced with shoulder formation [4,24], it is only natural to wonder if it has a similar impact on the heat fluxes. Therefore, as a second objective we also set out to answer the question 'Is the particle transport increase observed during the shoulder formation followed by an equivalent increase of energy transport?…”

Section: Introductionmentioning

confidence: 99%