Development of a Temperature Distributed Monitoring System Based On Raman Scattering in Harsh Environment

Abstract

International audienceRaman Distributed Temperature Sensors (RDTSs) offer exceptional advantages to monitor the envisioned French deep geological repository for nuclear wastes, called Cigéo. Both γ-ray and hydrogen release from nuclear wastes can strongly affect the temperature measurements made with RDTS. We present experimental studies on how the performances of RDTS evolve in harsh environments like those associated with γ-rays or combined radiations and H2 release. The response of two standard and one radiation tolerant multimode fibers (MMFs) are investigated. In all fibers the differential induced attenuation between Stokes and anti-Stokes signal, (αAS - αS) causes a temperature errors, up to 30° C with standard multimode fibers (100 m) irradiated at 10 MGy dose. This degradation mechanism that is more detrimental than the radiation induced attenuation (RIA) limiting only the sensing range. The attenuation in the [800-1600 nm] spectral range at room temperature is explored for the three fibers γ-irradiated and/or hydrogen loaded to understand the origin of the differential RIA. We show that by adapting the characteristics of the used fiber for the sensing, we could limit its degradation but that additional hardening by system procedure is necessary to correct the T error in view of the integration of our RDTS technology in Cigéo. The current version of our correction technique allows today to limit the temperature error to ~ 2° C for 10 MGy irradiated samples

Effects of gamma radiation on perfluorinated polymer optical fibers

“…Fiber-based systems have been exploited for strain [2], temperature [3] or humidity [4] sensing in radiation environments. Various fiber sensing schemes are being investigated, including distributed Rayleigh [3,5], Raman [6] or Brillouin [7] scattering techniques and fiber Bragg gratings or interferometric sensors [8,9]. Moreover, number of optical fiberbased systems has been developed for direct radiation sensing and monitoring [10e12].…”

Radiation Characterization of Optical Frequency Domain Reflectometry Fiber-Based Distributed Sensors

“…Among the different optical fiber sensing techniques, those based on light scattering are the most investigated: from Fiber Bragg Gratings (FBGs) for discrete measurements [4] to Brillouin [5], Raman [6] [7] and Rayleigh [8] for distributed measurements. The choice of one technique with respect to the others depends on the characteristics and the sensor profile of use.…”

Research on Noise Reduction Approach of Raman-Based Distributed Temperature Sensor Based on Nonlinear Filter

“…Raman-based distributed temperature sensor is widely used in power grid monitoring [1], mine safety monitoring [2], nuclear environmental safety monitoring [3] and other fields due to its strong resistance to electromagnetic and radiative interference and excellent distributed measurement capability.…”