High Radiation Fluence Tolerant Temperature Sensors for In-Core Use

The need for high stability measurement of temperature is essential for monitoring incore reactor use in planned Gen-IV reactor designs, especially the next generation nuclear plants (NGNP) such as the SFR (Sodium-cooled Fast Reactors). These reactors are planned to operate by means of fast neutron reactions with neutron fluence up to 1025cm-2. These operating conditions lead to material damage by displacement of the atoms which rapidly causes increased inaccuracy in temperature measurements using current technology. Accurate temperature measurements are needed to identify hot spots, control thermal cycles, to perform temperature compensation of other sensors, and is therefore critical to the safe and efficient operation of these reactors. A reactor monitoring system comprised of radiation tolerant fiber-optic based temperature solution and all purpose optical demodulation instrumentation is being proposed. The sensor will rely on measurement of material properties and optical response of stable materials to temperature in the presence of high radiation flux for extended periods of time. Commercial Applications and Other Benefits: Stabile temperature measurements and materials characterization will enable commercialization of Gen-IV reactor designs as well as increase safety in PWR (pressurized water reactors) and other Gen-III designs already in operation. Since the sensors will be radiation tolerant and high-fluence capable, they will also find application in space reactor applications, where long term reliability is essential