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Takayanagi, Tomohiro; Sugita, Moe; Ueno, Tomoaki*; Horino, Koki*; Ono, Ayato; Yamamoto, Kazami; Kinsho, Michikazu
IEEE Transactions on Applied Superconductivity, 32(6), p.4101405_1 - 4101405_5, 2022/09
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)In order to design a pulsed electromagnet, it is necessary to consider eddy currents that depend on the pattern shape of the pulse excitation, and to design the structure and set the operating parameters considering the fluctuation of the magnetic field distribution and its effect on heat generation. Evaluation tests of a new bump magnet for the J-PARC RCS showed that the magnetic field distributions at the rising edge of the trapezoidal pattern and at the flat top are different from each other. This was also confirmed by the 3D dynamic magnetic field analysis of OPERA-3d. Since the skin-depth due to eddy currents depends on the time variation of the waveform, the effect is the same as changing the shape of the coil. The measurement of the magnetic field distribution fluctuation was verified and evaluated using a flux meter, search coil, and Hall probe with different measurement principles.
Yamamoto, Kazami; Yamakawa, Emi*; Takayanagi, Tomohiro; Miki, Nobuharu*; Kamiya, Junichiro; Saha, P. K.; Yoshimoto, Masahiro; Yanagibashi, Toru*; Horino, Koki*; Nakanoya, Takamitsu; et al.
ANS RPSD 2018; 20th Topical Meeting of the Radiation Protection and Shielding Division of ANS (CD-ROM), 9 Pages, 2018/08
The existing beam power of the J-PARC Rapid Cycling Synchrotron is up to 500 kW, and higher radiation doses are concentrated in the injection area. These activations are caused by the interaction between the foil and the beam. To reduce dose exposure to workers near the injection point, we study a new design of the injection scheme. Experience has shown that eddy currents are generated in the metal flange near the magnet owing to the pulsed magnetic field, and the temperature exceeds 100 degrees C. The shield installed in the new injection system needs to have a layer structure, in which an insulator is inserted between iron shields to reduce the eddy current. From the results of the shielding calculation, even if 1 mm of polyethylene was inserted between two 9-mm-thick SUS 316 plates, which serve as shielding material, the shielding performance was reduced only about 5%, and we confirmed that it would function well.
Kurihara, Kenichi; Kawamata, Yoichi; Sueoka, Michiharu; Hosoyama, Hiroki*; Yonekawa, Izuru; Suzuki, Takahiro; Oikawa, Toshihiro; Ide, Shunsuke; JT-60 Team
Fusion Engineering and Design, 74(1-4), p.527 - 536, 2005/11
Times Cited Count：11 Percentile：59.86(Nuclear Science & Technology)Since tokamak magnetic fusion research has just made a step forward to an international collaborative project ITER, the existing tokamaks including JT-60 are expected to explore more advanced operation scenarios. To test those scenarios in the JT-60 experiment, the basic methods for understanding of plasma equilibrium have been developed. Some of them have been accomplished, and the other are being conducted as follows: (1) A complete plasma shape is precisely reproduced in real time. (2) Eddy current effects are considered for shape reproduction. (3) A plasma current profile in the poloidal cross-section is reproduced in real. (4) For long-pulse DT operation, a method is developed to correct the drifted signal of the integrator for a pick-up coil by employing distant sensor signals. In the symposium, those methods will be explained in detail with the experimental results at JT-60. On the basis of such discussion, we would like to envisage a future of plasma equilibrium control toward ITER and a fusion power plant.
Urata, Kazuhiro*; Suzuki, Yutaka*; Kudo, F.*; Kimura, Haruyuki; Miura, Yukitoshi; Yamamoto, Masahiro
Fusion Engineering and Design, 56-57, p.849 - 853, 2001/10
Times Cited Count：4 Percentile：33.39(Nuclear Science & Technology)no abstracts in English
Senda, Ikuo; Shoji, Teruaki; Araki, Masanori; ITER Japan Home Team; ITER Joint Central Team
International Journal of Applied Electromagnetics and Mechanics, 13(1-4), p.349 - 357, 2001/00
no abstracts in English
JNC TN9400 2000-021, 104 Pages, 2000/03
JNC-TN9400-2000-021.pdf:5.21MB
ln this report, research works performed in the Structura1 Safety Engineering Group of OEC/JNC are summarized as the final report of the doctoral fellowship. The main objective of this study is for the enhancement of the nondestructive evaluation techniques for structural components of both magnetic and nonmagnetic material. Studies in three topics have been carried out aiming at the quantitative evaluation of crack with the eddy current testing and the validation of a natural magnetic field based NDE method for detecting mechanical damages in a paramagnetic material. ln the first part of the study, an approach to the reconstruction of the natural crack was proposed and implemented with an idealized crack model for its validation. ln the second part, the correlation of the natural magnetization and the mechanical damages in the SUS304 stainless steel was investigated by using an experimental approach. ln part 3, an inverse method of the measured magnetic fields is proposed for the reconstruction of magnetic charges in the inspected material by using an optimization method and wavalet. As the first work, an approach to the reconstruction of an idealized natural crack of non-vanishing conductivity is proposed with use of signals of eddy current testing. Two numerical models are introduced at first for modeling the natural crack in order to represented it with a set of crack parameters. A method for the rapid prediction of the eddy current testing signals coming from these idealized cracks is given then by extending a knowledge based fast forward solver to the case of a non-vanishing conductivity. Based on this fast forward solver, the inverse algorithm of conjugate gradient method is updated to identify the crack parameters. Several examples are presented finally as a validation of the proposed strategy. The results show that both the two numerical models can give reasonable reconstruction results for signal of low noise. The model concerning the touch of ...
-collape-induced VDE and its underlying mechanism in the TVC tokamakNakamura, Yukiharu; J.B.Lister*; F.Hofmann*; Y.R.Martin*; J.-M.Moret*; P.Vyas*
Europhysics Conference Abstracts (CD-ROM), 23J, p.417 - 420, 1999/00
no abstracts in English
JNC TN9400 99-009, 39 Pages, 1998/12
In this paper, an approach to the reconstruction of an idealized natural crack of non-vanishing conductivity is proposed with use of signals of eddy current testing. Two numerical models are introduced at first for modeling a Stress Corrosion Crack (SCC) in order it possibly to be represented by a set of crack parameters. A method for rapid prediction of the eddy current testing signals arisen from these idealized cracks is given then by extending a knowledge based fast forward solver developed by authors to the case of a non-vanishing conductivity. On the other hand, the inverse algorithm of conjugate gradient method is improved to reconstruct the crack parameters and is implemented with the pick-up signals and gradients calculated by using the rapid forward solver. Several examples are presented finally for validating the proposed strategy. The results verified that both of the models can give reasonable reconstruction results in case of a low noise level. The model concerning the touch of crack surfaces with a conducting band region surrounded by the crack edge, however, is proved more efficient than the model using a conductivity distribution from the point of view of both reconstruction speed and accuracy.
Senda, Ikuo*; Shoji, Teruaki; Tsunematsu, Toshihide; *; Fujieda, Hirobumi*
Fusion Engineering and Design, 42, p.395 - 399, 1998/00
Times Cited Count：3 Percentile：31.81(Nuclear Science & Technology)no abstracts in English
Takase, Haruhiko; Senda, Ikuo; Araki, Masanori; Shoji, Teruaki; Tsunematsu, Toshihide
IAEA-CN-69/FTP/28, 4 Pages, 1998/00
no abstracts in English
; ;
PNC TN9410 97-087, 142 Pages, 1997/07
Computer data analysis is planned as an essential process to facilitate and speed up the ISI of MONJU steam generator tubes using the ECT technique. This process compares the phase and amplitude of the signal in a vector window in order to identify and categories defects. The categorization of the inspection signal requires a high level of precision. The analysis test was carried out taking the best operational conditions for reference. From this, the most accurate classification conditions were established. The MONJU PSI signal data was used to check the effectiveness of the process. The results are as follows. (A) Verification of the set parameter for off line processing. Automatic classification is possible for almost all the support plate signals. Classification of all the weld and bend signals was not possible. Therefore, the set parameter was selected for the category in which there were the largest number of signals was established. (B) Verification of the analysis processing conditions. The established analysis conditions allow automatic classification for about 80 to 85% of the signal comparison factor cases. Furthermore, it is possible to classify all the signals by additional operator intervention. In this way it is possible to analysis and evaluate all the MONJU steam generator tube ISI data. (C) Improvement of the data base. Evaluation of MONJU PSI flaw detection data was carried out by set parameter analysis. FOllowing these results the necessary data base for ISI signal evaluation was created.
; *; Ara, Katsuyuki
Electromagnetic Nondestructive Evalution, 0, p.223 - 230, 1997/00
no abstracts in English
Senda, Ikuo*; Shoji, Teruaki; Tsunematsu, Toshihide; *; Fujieda, Hirobumi*
Nuclear Fusion, 37(8), p.1129 - 1145, 1997/00
Times Cited Count：9 Percentile：33.74(Physics, Fluids & Plasmas)no abstracts in English
Senda, Ikuo*; Shoji, Teruaki; *; Fujieda, Hirobumi*; Tsunematsu, Toshihide
JAERI-Tech 96-016, 23 Pages, 1996/03
no abstracts in English
Ara, Katsuyuki
MSJ-94-1, 0, p.1 - 8, 1996/03
no abstracts in English
; *; Ara, Katsuyuki
First US-Japan Symp. on Advances in NDT, 0, p.98 - 103, 1996/00
no abstracts in English
; *; Ara, Katsuyuki
MAG-96-73, 0, p.73 - 82, 1996/00
no abstracts in English
; *; Ara, Katsuyuki
Nihon Oyo Jiki Gakkai-Shi, 20, p.633 - 636, 1996/00
no abstracts in English
; *; Ara, Katsuyuki
Denki Gakkai Rombunshi, A, 115(10), p.999 - 1006, 1995/10
no abstracts in English
Senda, Ikuo*; Shoji, Teruaki; Nishio, Satoshi; Tsunematsu, Toshihide; *; Fujieda, Hirobumi*
JAERI-Data/Code 95-010, 32 Pages, 1995/08
JAERI-Data-Code-95-010.pdf:1.02MB
no abstracts in English
