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Journal Articles

Dynamic analysis of ITER tokamak using simplified model for support structure

Takeda, Nobukazu; Shibanuma, Kiyoshi

Purazuma, Kaku Yugo Gakkai-Shi, 80(11), p.988 - 990, 2004/11

http://ci.nii.ac.jp/naid/110003827652

The simplified analytical model of the support structure composed of complicated structures such as multiple flexible plates was proposed for the dynamic analysis of the ITER major components of VV and TF coil. The support structure composed of flexible plates and connection bolts was modeled as a spring model composed of only two spring elements including the effect of connection bolts. The stiffness of both spring models for VV and TF coil agree well with that of shell models simulating actual structures such as flexible plates and connection bolts. Using the proposed model, the dynamic analysis of the VV and TF coil for the ITER were performed to estimate the integrity under the design earthquake at Rokkasho, a candidate of ITER site. As a result, it is found that the maximum relative displacement of 8.6 mm between VV and TF coil is much less than 100 mm, so that the integrity of the major components are ensured for the expected earthquake event.

Journal Articles

Status on seismic design and verification for ITER in Japan

Takeda, Nobukazu; Nakahira, Masataka; Tada, Eisuke; Fujita, Satoshi*; Fujita, Takafumi*

Nihon Jishin Kogakkai Rombunshu (Internet), 4(3), p.298 - 304, 2004/04

https://doi.org/10.5610/jaee.4.3_298

ITER is a Tokamak-type international fusion experimental device composed of superconducting magnets, a vacuum vessel, and so on. These are operated at a quie wide temperature ranging from 4K to 200 degree C. For this, multiple plates have been chosen as the machine support so as to peovide flexibility in the radial direction while keeping high rigidity vertically. This results in a low natural frequency of around 4Hz in the horizontal direction. Since those structures are designed in accordance with the IAEA seismic acceleration of 0.2g as a reference, a seismic isolation is required if earthquake-proof larger than 0.2g is necessary. Considering these conditions, analytical and experimental studies have been conducted to characterize the ITER dynamic response in Japan. This paper outlines the latest status on seismic design for ITER in Japan and evaluation on tokamak dynamic response and verification tests using scaled tokamak model.

Journal Articles

Singular point analysis

Tokuda, Shinji

Purazuma, Kaku Yugo Gakkai-Shi, 78(9), p.913 - 924, 2002/09

https://doi.org/10.1585/jspf.78.913

An introductory review is given on recent developments in the methods for stability analysis of a toroidally confined plasma. Emphasis is put on the perturbation analysis of a magnetohydrodynamic system that has the marginally stable state as a terminal point of continuous spectra. We address ourselves to the asymptotic matching method pertinent to such a problem. The Newcomb equation and inner-layer equations are essential ingredients in the methods and the numerical methods for solving them are discussed.

Journal Articles