Measurement of disruption forces in JET using fiber-optic sensors

C. Lescure, G. Fusiek, S. Hotchin, E. Ivings, M.F. Johnson, P. Niewczas, V. Riccardo, M. Walsh, A. West

Research output: Contribution to conferencePaper

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.
LanguageEnglish
Pages4
DOIs
Publication statusPublished - Jun 2009
EventProceedings - Symposium on Fusion Engineering -
Duration: 1 Jan 1900 → …

Conference

ConferenceProceedings - Symposium on Fusion Engineering
Period1/01/00 → …

Fingerprint

fiber optics
strain gages
sensors
Bragg gratings
fibers
transducers
connectors
rangefinding
cables
couplers
coils
optical fibers
broadband
vacuum

Keywords

  • Fiber-optic sensors
  • Fusion Energy
  • Electrical engineering
  • JET

Cite this

Lescure, C., Fusiek, G., Hotchin, S., Ivings, E., Johnson, M. F., Niewczas, P., ... West, A. (2009). Measurement of disruption forces in JET using fiber-optic sensors. 4. Paper presented at Proceedings - Symposium on Fusion Engineering, . https://doi.org/10.1109/FUSION.2009.5226470
Lescure, C. ; Fusiek, G. ; Hotchin, S. ; Ivings, E. ; Johnson, M.F. ; Niewczas, P. ; Riccardo, V. ; Walsh, M. ; West, A. / Measurement of disruption forces in JET using fiber-optic sensors. Paper presented at Proceedings - Symposium on Fusion Engineering, .
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abstract = "Monitoring the forces induced on the vacuum vesselwhen a disruption occurs is essential for the protection of themachine. Since divertor coils have been installed in JET, duringdisruptions a significant difference between the forces measuredon the top and the bottom of the machine has been observed. Inorder to investigate these further, optical fiber transducers FBGs(Fiber Bragg Gratings) were installed in addition to the currentlyused strain gauges. During VDE (Vertical Displacement Event)tests, these new transducers were used to measure different levelof disruptions ranging from 80T up to 230T vertical forces. Theresults were then compared with the strain gauges. The FBGmeasurement was carried out using a broadband light sourceilluminating an array of 4 FBGs through a combination ofdirectional couplers, connectors and fiber-optic cable. The forcesmeasured both by FBG and by the strain gauges are within thesame range, except for the initial swing where large randomdifferences are observed. The tests have demonstrated that theFBG-based force measurement system has adequate resolution(±1.52strain corresponding to a force of 4kN due to the geometryof the leg) and measurement range (50002strain or 13000kN) forthis application.",
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Lescure, C, Fusiek, G, Hotchin, S, Ivings, E, Johnson, MF, Niewczas, P, Riccardo, V, Walsh, M & West, A 2009, 'Measurement of disruption forces in JET using fiber-optic sensors' Paper presented at Proceedings - Symposium on Fusion Engineering, 1/01/00, pp. 4. https://doi.org/10.1109/FUSION.2009.5226470

Measurement of disruption forces in JET using fiber-optic sensors. / Lescure, C.; Fusiek, G.; Hotchin, S.; Ivings, E.; Johnson, M.F.; Niewczas, P.; Riccardo, V.; Walsh, M.; West, A.

2009. 4 Paper presented at Proceedings - Symposium on Fusion Engineering, .

Research output: Contribution to conferencePaper

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AU - Lescure, C.

AU - Fusiek, G.

AU - Hotchin, S.

AU - Ivings, E.

AU - Johnson, M.F.

AU - Niewczas, P.

AU - Riccardo, V.

AU - Walsh, M.

AU - West, A.

PY - 2009/6

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N2 - Monitoring the forces induced on the vacuum vesselwhen a disruption occurs is essential for the protection of themachine. Since divertor coils have been installed in JET, duringdisruptions a significant difference between the forces measuredon the top and the bottom of the machine has been observed. Inorder to investigate these further, optical fiber transducers FBGs(Fiber Bragg Gratings) were installed in addition to the currentlyused strain gauges. During VDE (Vertical Displacement Event)tests, these new transducers were used to measure different levelof disruptions ranging from 80T up to 230T vertical forces. Theresults were then compared with the strain gauges. The FBGmeasurement was carried out using a broadband light sourceilluminating an array of 4 FBGs through a combination ofdirectional couplers, connectors and fiber-optic cable. The forcesmeasured both by FBG and by the strain gauges are within thesame range, except for the initial swing where large randomdifferences are observed. The tests have demonstrated that theFBG-based force measurement system has adequate resolution(±1.52strain corresponding to a force of 4kN due to the geometryof the leg) and measurement range (50002strain or 13000kN) forthis application.

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Lescure C, Fusiek G, Hotchin S, Ivings E, Johnson MF, Niewczas P et al. Measurement of disruption forces in JET using fiber-optic sensors. 2009. Paper presented at Proceedings - Symposium on Fusion Engineering, . https://doi.org/10.1109/FUSION.2009.5226470