Fiber Optic Sensor for Simultaneous Measurement of Temperature and Pressure

Continued use of nuclear power is critical to meeting carbon emission goals and ensuring national security. Nuclear power production will rely on both current generation (LWR and PWR) as well as next generation designs including very-high-temperature, molten-salt, supercritical- water-cooled, gas-cooled, sodium-cooled, and/or lead-cooled reactors. The development and deployment of these high temperature and harsh environment reactors will require advanced sensors capable of operating in these environments. Luna’s core technology lies in Optical Frequency Domain Reflectometry (OFDR) utilizing the Rayleigh backscatter and/or Fiber Bragg Gratings within optical fiber to make temperature measurements. By adding a structure to the end of the fiber creating a Fabry-Perot Interferometer pressure can be measured using the same data system. Materials would be selected such that they are compatible with the anticipated environment and packaged into a deployable unit that could be installed into research and commercial facilities. This technology will provide for enhanced methods of measuring temperature and pressure in the same fiber simultaneously. During the Phase I effort, Luna will investigate the feasibility of the approach through design and modeling of a new sensor system, fabrication of a small scale prototype, experimental validation to demonstrate the sensor’s ability to measure temperature and pressure simultaneously, and finally operation in a research reactor for a duration that provides a total fluence on the order of 1018n/cm2. As the entire unit is housed in a metal tube, with the exception of an exposed fiber tip, we expect a relative straight forward path toward packaging the material for molten salt deployment, and will work with our industry partners during Phase II towards final deployment packaging. Simultaneous temperature and pressure measurement instrumentation will enable safe operation of Gen-IV reactor designs and PWR (pressurized water reactors) and other Gen-III reactor designs already in operation with a reduction of pressure vessel feedthrough per sensor required. Since the developed sensors will be radiation tolerant and high-temperature capable, they will also find application in space probes, rocket engine monitoring, rocket engine development and in gas turbine health monitoring.