Leak detection in insulated pipe for nuclear pressure boundary monitoring using optical fiber distributed temperature sensor

Early leak detection and localization in insulated pipe for nuclear power plant (NPP) pressure boundary were demonstrated using optical fiber distributed temperature sensor on a small-scale NPP test-bed. The results indicated that high-temperature vapor leaks in insulated pipe can be rapidly detected by real-time monitoring of temperature variations along the fiber, which is wrapped in a helical pattern around the pipeline within the insulation material.