Investigation of fuel retention via gas balance on HT-7

Cao, Bin; Li, J.G.; Hu, Jiansheng; Chen, Q.; Yu, Yaowei; Li, J.H.; Wu, Guopeng; Chen, Y.; Zuo, Guizhong

doi:10.1016/j.vacuum.2011.01.026

Cited by 3 publications

(8 citation statements)

References 10 publications

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“…Lithium has a strong capability of gaining a hydrogen isotope, and after wall conditioning with lithium, the amount of retained particles increases. This phenomenon was found on HT-7 [24]. The influence of lithium coating on wall retention is investigated in this paper.…”

Section: Introductionmentioning

confidence: 76%

“…It was observed that during the long pulse the fuel retention had three phases: a fast decrease, steady and zero retention. Zero retention means 100% recycling, which was not found in Tore Supra [3,13] or HT-7 [24], but was found in DIII-D [29] and JT-60U [30]. The H-mode discharges had a slightly lower retention than the L-mode discharges.…”

Section: Discussionmentioning

confidence: 91%

“…The total amount of retained particles during this phase was about 0.1×10 21 D. As shown in figure 5(c), the electron density decreased a little at the beginning of phase 3, because the gas puffing had stopped at this time, but was still controlled and remained steady until the end of the discharge. Near zero retention means almost 100% recycling, which was not found in Tore Supra [3] or HT-7 [24], but was found in DIII-D [29] and JT-60U [30]. Normally at the end of the discharge, the retention increases a little, because a lot of the particles from the plasma hit the wall and are temporarily absorbed by it.…”

Section: Retention Evolution During a Dischargementioning

confidence: 97%

“…In KSTAR with full graphite, the deuterium retention is increased with the amount of injected particles and the retention fraction is about 21% [22]. In HT-7 with carbon as a first wall, the retention fraction is about 40% [23,24], with Mo as the first wall, the retention fraction is about 10% [25], and after a lithium coating on the first wall the retention fraction is increased [24,25].…”

Section: Introductionmentioning

confidence: 98%

“…They both introduce a lot of hydrogen into the wall, which leads to high recycling because of isotopic exchange. In HT-7 after siliconization the retention fraction and H/(H+D) ratio increased after boronization [24]. Lithium coating is another useful wall conditioning method which has been explored since 2009 on EAST and has led to significant progress.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

The first results of deuterium retention on EAST with a full graphite wall via particle balance

Cao¹,

LI²,

Hu³

et al. 2017

Plasma Sci. Technol.

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This paper introduces the first results of deuterium retention on the Experimental Advanced Superconducting Tokamak (EAST) using particle balance. In the fall 2010 EAST experiments with a full graphite wall, the average deuterium retention fraction was about 19% (including disruptive shots) and 38% (not including disruptive shots). Fuel retention for the short-and longpulse discharge was different. The H-mode discharges had a slightly lower fuel retention than the L-mode discharges. However, it was observed that disruptions introduced outgassing from the wall. Wall conditioning, such as lithium coating, increases retention.

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Section: Introductionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 91%

Section: Retention Evolution During a Dischargementioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The first results of deuterium retention on EAST with a full graphite wall via particle balance

Cao¹,

LI²,

Hu³

et al. 2017

Plasma Sci. Technol.

View full text Add to dashboard Cite

show abstract

Comparison between gas puffing and supersonic molecular beam injection in plasma density feedback experiments in EAST

Zheng¹,

Li²,

Hu³

et al. 2013

Plasma Phys. Control. Fusion

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To achieve desirable plasma density control, a supersonic molecular beam injection (SMBI) feedback control system has been developed recently for the EAST tokamak. The performance of the SMBI and gas puffing (GP) feedback systems were used and compared. The performance of pulse width mode is better than that of pulse amplitude mode when GP was used for density feedback control. During one-day experiments, the variation of gas input and wall retention can be clarified into two stages. In the first stage the retention ratio is as high as 80-90%, and the gas input is about an order of 10 22 D 2 . However, in the second stage, the retention ratio is at a range of 50-70%. The gas input of a single discharge is small and the net wall retention grows slowly. The results of the SMBI feedback control experiment was analyzed. The shorter delay time of SMBI makes it faster at feeding back control the plasma density. The result showed that, compared with GP, the gas input of SMBI was decreased ∼30% and the wall retention was reduced ∼40%. This shows SMBI's advantage for the long pulse high density discharges in EAST.

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Deuterium retention characteristics in Li film by coating and during flowing liquid Li limiter operation in experimental advanced superconducting tokamak

Zuo

Maingi

et al. 2020

Plasma Phys. Control. Fusion

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Lithium (Li) is a promising low-Z material for particle recycling and impurity control to improve plasma performance in fusion devices. In the experimental advanced superconducting tokamak (EAST), Li coating has become a routine method for wall conditioning, and a flowing liquid Li (FLiLi) limiter has been successfully tested several times. Deuterium retention characteristics in the Li film coated on the international thermonuclear experimental reactor-like tungsten divertor and FLiLi during plasma discharges, which is important for the utilization of Li in future fusion devices, were investigated in EAST. It is found that the absorption of the fuel particles by Li coatings decreases gradually, and recycling gradually increases over a series of discharges. The maximum net amount of deuterium retained reached ∼0.8 g, corresponding to 12% deuterium in the Li. This corresponds to a whole day’s worth of shots with a total of 87 plasma discharges and a total of ∼640s plasma time after 11.75 g Li was deposited. Compared to the Li coating, it is shown that FLiLi continuously traps fuel particles and achieves a higher deuterium retention ratio over both the short- and long-term, leading to lower recycling. Meanwhile, it is also observed that the fuel particle retention ratio increases when FLiLi is closer to the plasma. This result is likely due to higher plasma heating power and limiter temperature, which cause an increased Li efflux from FLiLi due to a higher limiter temperature, which then redeposits on the other plasma-facing surfaces and increases fuel particle absorption. It is estimated that ⩾80% of the retained D particles are captured by the continual renewal of the Li redeposition film during the FLiLi operation. This investigation would also be useful for D/T retention in future fusion devices if Li is used as a plasma-facing component.

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Investigation of fuel retention via gas balance on HT-7

Cited by 3 publications

References 10 publications

The first results of deuterium retention on EAST with a full graphite wall via particle balance

The first results of deuterium retention on EAST with a full graphite wall via particle balance

Comparison between gas puffing and supersonic molecular beam injection in plasma density feedback experiments in EAST

Deuterium retention characteristics in Li film by coating and during flowing liquid Li limiter operation in experimental advanced superconducting tokamak

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