Particle balance under global wall saturation in long-pulse discharges of JT-60U

Nakano, T.; Asakura, N.; Takenaga, H.; Kubo, H.; Shimizu, Kazuya; Kawashima, H.

doi:10.1016/j.jnucmat.2007.01.221

Cited by 14 publications

(18 citation statements)

References 11 publications

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“…In the long-term retention processes, the possible saturation of the retention, the so called 'wall saturation' has been extensively investigated in JT-60U [35][36][37][38][39] for long discharge operations (>25-30 s). Some experiments were also reported for a series of long discharges in TS before the CIEL upgrade [40] when 'only' 80% of the PFCs were actively-cooled and also in TRIAM-1 M for the discharge lasting more than 5h00 [41].…”

Section: Short and Long-term Retentionmentioning

confidence: 99%

Fuel retention in tokamaks

Loarer

2009

Journal of Nuclear Materials

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Section: Short and Long-term Retentionmentioning

confidence: 99%

Fuel retention in tokamaks

Loarer

2009

Journal of Nuclear Materials

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“…2) [9,30]. In JT60U, improving divertor pumping by optimizing the plasma position was demonstrated to efficiently reduce the density increase rate [2,31]. However, the wall inventory is estimated to be a much larger particle reservoir than the plasma content, and very sensitive to T surf variations.…”

Section: Density Controlmentioning

confidence: 99%

Key plasma wall interaction issues towards steady state operation

Tsitrone

2007

Journal of Nuclear Materials

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“…Hydrogen recycling in long duration discharges has been studied using global particle balance analysis [6,9,[21][22][23][24]. The global particle balance in the main chamber can be written as:…”

Section: Global Particle Balancementioning

confidence: 99%

Plasma-Wall Interaction Study towards the Steady State Operation

Sakamoto

Higashizono

Zushi

et al. 2010

Plasma and Fusion Research

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Various phenomena of plasma-wall interactions during long duration discharges in TRIAM-1M are investigated from macroscopic and microscopic viewpoints. It is found that the density dependence of the hydrogen neutral flux decay length is not very sensitive to the density (i.e.n −0.2 e ). Neutral transport through the scrape-off layer is important for structural formation of hydrogen recycling. The hydrogen retention in the co-deposited layer, which was obtained using a material probe during long duration discharges, is consistent with the global wall pumping rate estimated from particle balance analysis. The wall temperature and co-deposition play important roles on hydrogen re-emission and hydrogen absorption, respectively. Oxygen impurities should affect the erosion and deposition properties of the plasma-facing wall as well as the hydrogen retention property of the co-deposited layer. The co-deposition of hydrogen with molybdenum and the oxygen impurities both play important roles in the hydrogen recycling. c 2010 The Japan Society of Plasma Science and Nuclear Fusion ResearchKeywords: plasma-wall interaction, steady state operation, tokamak, hydrogen recycling, co-deposition DOI: 10.1585/pfr.5.S2009 InroductionPlasma-wall interaction (PWI) issues are strongly related to plasma performance and stable operation, and are especially critical for a steady state operation (SSO) of fusion plasma [1][2][3]. PWI phenomena contain processes over a wide range of time and length scales. The time scale characteristics of PWI extend from 10 ps (radiation damage) to ≤ ms (hydrogen diffusion in material), order of 10's seconds (recycling variation) and order of 10 2 -10 3 seconds (wall saturation) up to order of 10 6 (life time of plasmafacing components). On the other hand, the characteristics of the PWI length scale range from the nm order (microstructure) to tens of m order (global particle balance) with μm (dust) and cm (hot spot) orders in between. Therefore, PWI phenomena must be comprehensively investigated from multiscale viewpoints because the scale length phenomena are interrelated.In TRIAM-1M, which has SSO capability, plasmawall interaction experiments have been carried out extensively from microscopic and macroscopic viewpoints [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In this paper, various phenomena of PWI are investigated focusing on their length scales, which are classified according to the length from the order of a diameter of the torus to that of the microstructure of the deposits on author's e-mail: sakamoto@triam.kyushu-u.ac.jp the wall. Experimental SetupTRIAM-1M is a superconducting tokamak. Sixteen superconducting toroidal field coils composed of Nb 3 Sn were installed. The toroidal magnetic field was up to 8 T and in the steady state. The poloidal field coils of Cu were mounted on a vacuum vessel with a D-shaped cross-section, a horizontal length of 0.26 m, and the vertical length of 0.38 m. The major radius of the center of the vacuum vessel was 0.84 m. The entire machine was installed in...

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Particle balance under global wall saturation in long-pulse discharges of JT-60U

Cited by 14 publications

References 11 publications

Fuel retention in tokamaks

Fuel retention in tokamaks

Key plasma wall interaction issues towards steady state operation

Plasma-Wall Interaction Study towards the Steady State Operation

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