Performance of JT-60 divertor plates

Ando, T.; Takatsu, H.; Nakamura, Hiroo; Yamamoto, Masahiro; Kodama, K.; Arai, Takashi; Shimizu, Masatsugu; Fukaya, K.; Eto, Minoru; Oku, Tatsuo

doi:10.1016/0022-3115(91)90095-o

Cited by 12 publications

(4 citation statements)

References 8 publications

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“…Furthermore, redeposition on plasma-facing materials may largely affect thermal response [2], as well as hydrogen trapping [3] and diffusion [4] properties. In the last decade, intensive morphological studies on redeposition layers were conducted using scanning electron microscopy (SEM) [5][6][7]. Meanwhile, few structural analyses were conducted by using transmission electron microscopy (TEM) [8].…”

Section: Introductionmentioning

confidence: 99%

Transmission electron microscopy of redeposition layers on graphite tiles used for open divertor armor of JT-60

Gotoh

Arai

Yagyu

et al. 2004

Journal of Nuclear Materials

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Section: Introductionmentioning

confidence: 99%

Transmission electron microscopy of redeposition layers on graphite tiles used for open divertor armor of JT-60

Gotoh

Arai

Yagyu

et al. 2004

Journal of Nuclear Materials

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“…Runaway electrons can be suppressed or terminated by a large plasma shift, as observed in many tokamaks (e.g., Refs [8,9]). However, this avoidance method with a large plasma shift is not ideal, because it will cause serious problems in tokamak fusion reactors due to (i) high local heat flux on the first wall components, such as that observed in the early JT-60 experiments [10,11], and (ii) large halo currents producing intense electromagnetic forces [12,13]. Thus, further investigations are required to clarify the conditions under which runaway electron generation can be avoided.…”

Section: Introductionmentioning

confidence: 99%

Generation and termination of runaway electrons at major disruptions in JT-60U

1999

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The operation conditions to avoid runaway electron generation at the major disruption have been investigated in JT-60U tokamak plasmas. It has been found that runaway electrons are not observed for low Bt of ⩽ 2.2 T or low plasma current quench rates (Iγ ≡ -(dIp/dt)/Ip) of <50 s-1. Furthermore, they are not observed for low effective safety factors defined at the plasma edge (qeff) of ⩽ 2.5 even for high Iγ of 300-400 s-1, which is the case for uncontrolled disruptions accompanied by large plasma displacements (e.g., vertical displacement events (VDEs)). On the other hand, in controlled disruptions with small plasma shifts, qeff easily increases above 8, and runaway electrons are observed even for low current quench rates of 50-100 s-1. Furthermore, it has been found that in these position controlled disruptions the runaway current tail can rapidly decay even for zero or weakly positive plasma surface voltages. These observations of the avoidance and termination of runaway electrons suggest an anomalous loss mechanism for runaway electrons.

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“…The main operation parameters are summarized in Table 1 [6][7][8]. After venting the vacuum chamber, several types of dust-like pieces were found in the vacuum vessel, flake-like dust, graphite, and metal pieces.…”

Section: Methodsmentioning

confidence: 99%