Using the sounds of nuclear power

Abstract

The generation of sound by heat has been documented as an “acoustical curiosity” since a Buddhist monk reported the loud tone generated by a ceremonial rice-cooker in 1568. Over the last four decades, significant progress has been made in understanding “thermoacoustic processes,” enabling the design of thermoacoustic engines and refrigerators. We have developed and tested a thermoacoustic engine that exploits the energy-rich conditions in the core of a nuclear reactor. The heat engine is self-powered and can wirelessly transmit the temperature and reactor power by generation of a pure tone which can be detected outside the reactor. We report here the first use of a fission-powered thermoacoustic engine capable of serving as a performance and safety sensor in the core of a research reactor and present data from two hydrophones in the coolant (far from the core) and an accelerometer attached to a structure outside the reactor. These measurements confirmed that the frequency of the sound produced indicates the reactor’s coolant temperature and that the amplitude (above an onset threshold) is related to the reactor’s operating power level. These signals can be detected even in the presence of substantial background noise generated by the reactor’s fluid pumps. [Work supported by Idaho National Laboratory and Westinghouse Electric Co.]