Fiber-optic Temperature Sensor Using a Silicone Oil and an OTDR

Abstract - In this study, we developed a fiber-optic temperature sensor (FOTS) based on a silicone oil and an optical time domain reflectometer (OTDR) to apply the measurement of a coolant leakage in the nuclear power plant. The sensing probe of the FOTS consists of a silicone oil, a stainless steel cap, a FC terminator, and a single mode optical fiber. Fresnel reflection arising at the interface between the silicone oil and the single mode optical fiber in the sensing probe is changed by varying the refractive index of the silicone oil according to the temperature. Therefore, we measured the optical power of the light signals reflected from the sensing probe. The measurable temperature range of the FOTS using a Cu-coated silica fiber is from 70℃ to 340℃ and the maximum operation temperature of the FOTS is sufficient for usage at the secondary system in the nuclear power plant.Key Words : Fiber-optic temperature sensor, Silicone oil, OTDR, Fresnel reflection, Coolant leakage †Corresponding Author : School of Biomedical Engineering,College of Biomedical & Health Science, BK21 Plus Research Institute of Biomedical Engineering, Konkuk University, KoreaE-mail : bslee@kku.ac.kr* School of Biomedical Engineering, College of Biomedical & Health Science, BK21 Plus Research Institute of Biomedical Engineering, Konkuk University, Korea** Department of Organic Materials & Fiber Engineering, College of Engineering, Soongsil University, KoreaReceived : August 11, 2015; Accepted : October 29, 2015