C56-40.W Optical Fiber Based Distributed Radiation Detection

Continued use of nuclear power is critical to meeting carbon emissions goals, and the safe operation of these facilities will require advanced sensors capable of operating in the harsh, high temperature irradiated environment of a reactor core. Power distribution is a critical reactor measurement, and the current approach of using Local Power Range Monitors (LPRMs) requires periodic calibration via a complex process of installing traversing in-core probes (TIPs) alongside the LPRMs. Installing a permanent system of sensors for LPRM calibration that do not degrade over time would eliminate the risk of releasing radioactive material caused by inserting and removing the TIPs and would also increase the safety and speed of the calibration process while reducing the cost and complexity of the process. Luna and The Ohio State University (OSU) propose to combine their expertise to develop an innovative Optical Fiber Based Distributed Radiation Sensor based on a Gamma Thermometer. Luna’s core technology lies in Optical Frequency Domain Reflectometry (OFDR), which enables precise measurement of temperature using Fiber Bragg Gratings (FBG’s) that are written at intervals along a section of radiation hardened optical fiber. By producing sensors where distributed fiber-optic temperature sensors are integrated into the core and shell of a coaxial tube where the core is a radiation sensitive material that heats upon exposure to radiation a difference in temperature between the two fibers can be measured to determine the radiation induced heating withing the core of the sensor, thus providing a distributed radiation probe. An array of sensors can be used to measure the power distribution in the reactor core. During the Phase I effort, Luna and OSU will investigate the feasibility of the approach through design and modeling of a new neutron flux sensor probe, fabrication of a gamma thermometer prototype, experimental validation to demonstrate the sensor’s ability to measure real-time radiation gamma-dose in an operational research reactor and determine a route towards construction of the distributed neutron flux probe in Phase II. Luna is teaming with Dr. Tom Blue from OSU, who will assist with design, modeling, and testing of the gamma thermometer in the Ohio State University Research Reactor (OSURR), a 500 kW Materials Testing Reactor. Luna will fabricate the radiation probes and conduct extensive modeling, temperature testing and calibration of the completed probes. In addition, Luna will provide sensors, electronics, data analysis and on-site personnel support for the testing at OSU. Luna has successfully transitioned fiber optic sensing technology from the laboratory to commercial products, and this innovation would be integrated with our existing product line. It is anticipated that the resulting product could have significant commercial potential in the nuclear reactor sensor market.