Optical Fiber Temperature Sensor Performance Test in a Metallic Capillary Tube at High Temperatures

Accurately measuring temperature at elevated temperature ranges is crucial for many industrial purposes. With the deployment of several advanced nuclear reactors on the horizon, the ability to instrument in these harsher environments at high temperatures and get accurate readings is needed. One potential solution is optical fiber temperature sensors. These sensors are capable of measuring temperatures with great spatial and temporal resolution up to around 600 °C. For use in instrumenting next generation reactors the performance up to 1000 °C is of interest. This work presents tests on fiber optic temperature sensors operating on the Rayleigh backscatter principle with cross validation from thermocouples. The results of each measurement technique were compared at high temperature to determine the accuracy of each instrument and to determine if optical fiber temperature sensors can be used beyond their typical operating range, targeting advanced reactor conditions.