Assessment of the environmental effects on the ITER FOCS operating in reflective scheme with Faraday mirror

Willem Leysen; Andrei Goussarov; Patrice Mégret; Marc Wuilpart

doi:10.1016/j.fusengdes.2019.01.086

Assessment of the environmental effects on the ITER FOCS operating in reflective scheme with Faraday mirror

Willem Leysen, Andrei Goussarov, Patrice Mégret, Marc Wuilpart

Nuclear Engineering Office

Research output › peer-review

Abstract

Plasma current measurements will play an important role in ITER to provide real-time plasma control and machine protection. Performance of standard electromagnetic sensors may be not sufficient to fulfill this task due to a combined effect of steady-state operation and the presence of strong nuclear radiation. The Fiber Optics Current Sensor (FOCS) is a back-up system included in the ITER design. Faraday mirror (FM) can be a part of the FOCS, which allows to improve the system performance. It is required that the polarization rotation angle is equal to 90° with acceptable deviations below 0.3°. We have experimentally investigated the effect of thermal perturbations and gamma-radiation on the rotation angle of commercial FMs. The FM rotation thermal sensitivity was found to be in a range 0.105 – 0.124°/°C. Gamma-irradiation resulted in a 1.2° change, saturated after a 12.5 kGy dose. Based on these results we conclude that the cubical area is the preferable location for the FM
despite that implies placing additional link fibers to reach the ITER vacuum Vessel.

Original language	English
Pages (from-to)	805-808
Number of pages	4
Journal	Fusion Engineering & Design
Volume	146
Issue number	A
DOIs	https://doi.org/10.1016/j.fusengdes.2019.01.086
State	Published - 1 Sep 2019
Event	2018 - SOFT: 30th edition of the Symposium on Fusion Technology - Giardini Naxos, Messina, Sicily Duration: 16 Sep 2018 → 21 Sep 2018

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Cite this

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title = "Assessment of the environmental effects on the ITER FOCS operating in reflective scheme with Faraday mirror",

abstract = "Plasma current measurements will play an important role in ITER to provide real-time plasma control and machine protection. Performance of standard electromagnetic sensors may be not sufficient to fulfill this task due to a combined effect of steady-state operation and the presence of strong nuclear radiation. The Fiber Optics Current Sensor (FOCS) is a back-up system included in the ITER design. Faraday mirror (FM) can be a part of the FOCS, which allows to improve the system performance. It is required that the polarization rotation angle is equal to 90° with acceptable deviations below 0.3°. We have experimentally investigated the effect of thermal perturbations and gamma-radiation on the rotation angle of commercial FMs. The FM rotation thermal sensitivity was found to be in a range 0.105 – 0.124°/°C. Gamma-irradiation resulted in a 1.2° change, saturated after a 12.5 kGy dose. Based on these results we conclude that the cubical area is the preferable location for the FMdespite that implies placing additional link fibers to reach the ITER vacuum Vessel.",

keywords = "ITER, Radiation effects, Magnetic diagnostics, Plasma current measurements, Fiber optics current sensor, Faraday mirror",

author = "Willem Leysen and Andrei Goussarov and Patrice M{\'e}gret and Marc Wuilpart",

note = "Score=10; 2018 - SOFT : 30th edition of the Symposium on Fusion Technology ; Conference date: 16-09-2018 Through 21-09-2018",

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T1 - Assessment of the environmental effects on the ITER FOCS operating in reflective scheme with Faraday mirror

AU - Leysen, Willem

AU - Goussarov, Andrei

AU - Mégret, Patrice

AU - Wuilpart, Marc

N1 - Score=10

PY - 2019/9/1

Y1 - 2019/9/1

N2 - Plasma current measurements will play an important role in ITER to provide real-time plasma control and machine protection. Performance of standard electromagnetic sensors may be not sufficient to fulfill this task due to a combined effect of steady-state operation and the presence of strong nuclear radiation. The Fiber Optics Current Sensor (FOCS) is a back-up system included in the ITER design. Faraday mirror (FM) can be a part of the FOCS, which allows to improve the system performance. It is required that the polarization rotation angle is equal to 90° with acceptable deviations below 0.3°. We have experimentally investigated the effect of thermal perturbations and gamma-radiation on the rotation angle of commercial FMs. The FM rotation thermal sensitivity was found to be in a range 0.105 – 0.124°/°C. Gamma-irradiation resulted in a 1.2° change, saturated after a 12.5 kGy dose. Based on these results we conclude that the cubical area is the preferable location for the FMdespite that implies placing additional link fibers to reach the ITER vacuum Vessel.

AB - Plasma current measurements will play an important role in ITER to provide real-time plasma control and machine protection. Performance of standard electromagnetic sensors may be not sufficient to fulfill this task due to a combined effect of steady-state operation and the presence of strong nuclear radiation. The Fiber Optics Current Sensor (FOCS) is a back-up system included in the ITER design. Faraday mirror (FM) can be a part of the FOCS, which allows to improve the system performance. It is required that the polarization rotation angle is equal to 90° with acceptable deviations below 0.3°. We have experimentally investigated the effect of thermal perturbations and gamma-radiation on the rotation angle of commercial FMs. The FM rotation thermal sensitivity was found to be in a range 0.105 – 0.124°/°C. Gamma-irradiation resulted in a 1.2° change, saturated after a 12.5 kGy dose. Based on these results we conclude that the cubical area is the preferable location for the FMdespite that implies placing additional link fibers to reach the ITER vacuum Vessel.

KW - ITER

KW - Radiation effects

KW - Magnetic diagnostics

KW - Plasma current measurements

KW - Fiber optics current sensor

KW - Faraday mirror

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