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Uehara, Kazuya; Tsuzuki, Kazuhiro; Amemiya, Hiroshi*; Nagashima, Yoshihiko*; Hoshino, Katsumichi; Sadamoto, Yoshiro*
Japanese Journal of Applied Physics, Part 2, 45(24), p.L630 - L633, 2006/07
Times Cited Count：3 Percentile：12.93(Physics, Applied)Data for detecting the magnetic flux surfaces at the edge plasma in tokamak are presented. When the magnetic surfaces are moved by the plasma jog, it is observed that a current increment appears in the two set of double probe whose front surfaces are shifted by a small distance and that the difference of these two currents through the differential amplifier giving a signal of the arrival of the separatrix also appears, where we refer the separatrix point as a typical position of the magnetic flux surfaces. It is confirmed that magnetic flux surfaces are located by a few cm outward from that calculated by the eqfit-code (EQFIT) and the absolute value of its deviation is identified. This identification is supported by the result of observation of the correlation of the floating potential fluctuation between two different points using one probe pin of the same differential double probe. The ion temperature and the space potential are observed by the another use of the differential double probe are modified following the estimated real magnetic surfaces positions.
Amemiya, Hiroshi*; Uehara, Kazuya
Japanese Journal of Applied Physics, Part 1, 45(1A), p.247 - 249, 2006/01
Times Cited Count：4 Percentile：17.08(Physics, Applied)A method for detecting the separatrix surface in the edge plasma in Tokamak is presented. Two sets of double probes whose front surfaces are shifted by a small distance are mounted and the difference of the currents is measured using a differential amplifier. When the separatrix surface reaches the probes, a current increment appears in the differential amplifier, giving a signal of the arrival of the separatrix. Procedures of obtaining plasma parameters including the ion temperature are described.
Amemiya, Hiroshi*; Wada, Motoi*; Toyoda, Hirotaka*; Nakamura, Keiji*; Ando, Akira*; Uehara, Kazuya; Oyama, Koichiro*; Sakai, Osamu*; Tachibana, Kunihide*
Purazuma, Kaku Yugo Gakkai-Shi, 81(7), p.482 - 525, 2005/07
This article is asked to write by the Japan Society of Plasma Science and Nuclear Fusion Research. The probe diagnostics in fusion plasma is explaind for many readers of the Journal of Plasma and Fusion Research, who have much concerned on various aspects.In section one, the method to estimate the electron temperature and the density as well as the electron energy distribution function with the single probe is given. In section two, the method to estimate the ion temperature and the flow velocity with the double probe is given. The practical measurements are explained introducing the data obtained at JFT-2, JFT-2a and JFT-2M in JAERI tokamak.
*
JNC TJ8400 2003-005, 126 Pages, 2003/03
JNC-TJ8400-2003-005.pdf:7.13MB
The main objectives of future research and development of geological disposal are to confirm that previous investigation and assessment method which have been arranged for generic geological environment will apply to real geological disposal environment, and the margin of system performance, which was assessed under simple and conservative viewpoint in the past, with assessment and recognition long term behavior of realistic system. Under present condition, we organized clay science specialist committee in Nuclear Safety Research Association and considered following themes comprehensively. (1)To confirm the assessment methods for log term stability of the buffer in 'H12: Project to establish the scientific and technical basis for HLW disposal in Japan' and in other performance assessment reports, and to pick up subjects from them. (2)Review on the research for long term stability assessment in Japan Nuclear Cycle Development Institute and in other researchers.
Oba, Takanobu*
JNC TJ8400 2003-004, 53 Pages, 2003/03
JNC-TJ8400-2003-004.pdf:2.82MB
The stability of smectite under the bulk composition of high iron content is as follows:(1) and (2). (1)In early burial diagenesis, the chemical variations of chlorite and dioctahedral. smectite in Tertiary formations of Niigata prefecture (2)The experiment of the stability of smectite in iron - rich bulk composition under oxygen fugacity. In the present study, the results are as follows: (1)Samples were taken from the cores and cuttings of exploratory test well of Oguni. The trioctahedral smectite in tertiary formation decreases with a depth. Below 3800m, Si content of chlorite increases with a depth. In the study, corrensite at 2700m depth has higher Si content, as compared to chlorite at 3800m. Mg/(Mg+Fe) ratios of chlorite/smectite interstratified mineral increase with increasing Si content regardless of the depth. (2)Chlorite/smectite interstratified mineral forms at 250
C on the composition of the starting material of Mont:Mt=5:5. Chlorite did not crystallize by using of the starting material of Sap:Mt=5:5 at 250C. At 400C, montmorillonite did not decompose on the starting material composition with low iron content. The iron density is very important for the stability of smectite.
Oba, Takanobu*
JNC TJ8400 2001-054, 39 Pages, 2002/03
JNC-TJ8400-2001-054.pdf:2.98MB
The purpose of investigation is as follows :(1) and (2). (1) The observation of the occurrence of chlorite and illite in Tertiary formations of Niigata prefecture. (2) The preliminary experiment of the stability of smectite in iron-rich bulk composition under oxygen fugacity. In the present study, the results are as follows: Mg/(Mg+Fe) ratio and Si of chlorite in the Tertiary sediment increase with depth in the Oguni well of Japan National Oil Corporation. The chemical variation of chlorite suggests that chlorite is rich in iron, in early burial diagenesis. At 350C, montmolorillonite decomposed to quartz, on the other hand saponite break decomposed to a 1:1 regularly interstratified mineral, corrensite with 31.9
, mica/smectite interstratified mineral with 27.8 and quartz. As compared with montmolorillonite and saponite, saponite is unstable at low temperature.
*
JNC TJ8400 99-031, 100 Pages, 1999/04
In order to clarify the stability of smectite for long range, three thema following below were studied in this paper. (1)Mineralogical study on bentonite contacted with iron (2)Fe concentration in carbonate nodules of bentonite ore deposit (3)The alteration effect of smectite to illite or chlorite by Al, Ca, K and Fe concentrations. The results in each part were followed below. (1)Bentonite contacted with iron turned into brown from green in color. Constituent minerals; smectite were not changed in mineralogical properties. (2)In Tsukinuno bentonite mine, Ca, Mg, Fe and Mn were concentrated in the carbonate minerals ; Ca (Mg, Fe, Mn) (CO
)
.. Dolomite crystals of nodules has the zonal structure where Fe is poor in core and richi in rim. (3)Fe-chlorite was synthesized at 0.1 GPa and 450C by using the mixtures of Kpa-F or SWy-1, and magnetite. The interstratified I/S, which synthesized in the previous short run (20 days), disappear at 365 days. This experimental results suggest that chlorite appears at 350C in the longer run than the previous short run. At 125 C, K-concentration is more important for K-fixation in smectite layer than Ca content in K-concentration of 0.5 N(20000ppm). In the longe run than 763 days, Ca content in K-concentration of 0.05N (2000ppm) inhibits an active effect of K-fixation in smectite layer.
Uehara, Kazuya; Asakura, Nobuyuki; Sadamoto, Yoshiro*; Kawashima, Hisato; Kubo, Hirotaka; Nakano, Tomohide; Takenaga, Hidenobu; Fujimoto, Kayoko; Amemiya, Hiroshi*; Saito, Yoshifumi*
no journal, ,
The temperature and energy of electrons are important issues when energy and particle fluxes to the divertor are evaluated. To do this, we have analyzed the electron energy distribution function by differentiating the probe current with respect to the probe voltage numerically, where probe current has been measured in the divertor plasma of JT-60U. We have evaluated the electron temperature and the shape of the distribution function when the X point MARFE and the plasma detachment are formed.
