Measurement of disruption forces in JET using fiber-optic sensors

Lescure, C. and Hotchin, S. and Ivings, E. and Johnson, M. F. and Riccardo, V. and Walsh, M. and West, A. and Fusiek, G. and Niewczas, P.; (2009) Measurement of disruption forces in JET using fiber-optic sensors. In: 2009 23rd IEEE/NPSS Symposium on Fusion Engineering. IEEE/NPSS Symposium on Fusion Engineering . IEEE, USA, pp. 1-4. ISBN 9781424426355 (https://doi.org/10.1109/FUSION.2009.5226470)

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Abstract

Monitoring the forces induced on the vacuum vessel when a disruption occurs is essential for the protection of the machine. Since divertor coils have been installed in JET, during disruptions a significant difference between the forces measured on the top and the bottom of the machine has been observed. In order to investigate these further, optical fiber transducers FBGs (Fiber Bragg Gratings) were installed in addition to the currently used strain gauges. During VDE (Vertical Displacement Event) tests, these new transducers were used to measure different level of disruptions ranging from 80T up to 230T vertical forces. The results were then compared with the strain gauges. The FBG measurement was carried out using a broadband light source illuminating an array of 4 FBGs through a combination of directional couplers, connectors and fiber-optic cable. The forces measured both by FBG and by the strain gauges are within the same range, except for the initial swing where large random differences are observed. The tests have demonstrated that the FBG-based force measurement system has adequate resolution (±1.52strain corresponding to a force of 4kN due to the geometry of the leg) and measurement range (50002strain or 13000kN) for this application.

  • Item type:Book Section
    ID code:14986
    Dates:
    Date
    Event
    28 August 2009
    Published
    5 June 2009
    Published Online
    Notes:© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
    Subjects:Technology > Electrical engineering. Electronics Nuclear engineering
    Department:Faculty of Engineering > Electronic and Electrical Engineering
    Depositing user: Strathprints Administrator
    Date deposited:12 May 2011 14:17
    Last modified:08 Apr 2024 14:07
    URI:https://strathprints.strath.ac.uk/id/eprint/14986
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