Thermoacoustic engines as self-powered sensors within a nuclear reactor

Abstract

The core of a nuclear reactor is a particularly harsh environment when functioning properly. When there is an “incident,” possibly with the loss of electrical service that accompanied the earthquake and tsunami that struck the Fukushimi Daiichi reactors on 11 March 2011, the term “harsh” seems too tame. We review the development and testing of very simple standing-wave thermoacoustic engines that can be configured as nuclear fuel rods to exploit the temperature differences within that environment rather than try to shield the sensor from “harshness” [U.S. Pat. Appl. Serial No. 13/968,936 (Aug. 16, 2013)]. Those engines produce high amplitude sound that couples to the surrounding heat-transfer fluid to telemeter the information (as frequency and amplitude) to the exterior of the reactor vessel, again without requiring external electrical power. Laboratory results will demonstrate measurement of coolant temperature, identify evolved gases, and provide information about changes in porosity of solids. Thermoacoustic resonances are maintained without use of either an explicit physical hot or cold heat exchanger—a ceramic “stack” is the only required component. We suggest extensions of this approach to other processes that generate substantial temperature gradients, such as industrial crucibles for melting glasses and metals. [Work supported by the U.S. Department of Energy.]