The Development of an Acoustical Thermometer for a Graphite Matrix Nuclear Fuel Element

The development of an acoustical thermometer for use in graphite matrix nuclear fuel elements is described. Test results indicate that this thermometer accomplished the objective of automatically, accurately, and reliably recording temperatures of a number of sensors. The acoustical thermometer system offers a wider choice of signal transmission line and sensor materials than conventional thermometer systems, since it does not require the use of electrical insulators or the conductors in them. This advantage was the main reason for choosing the acoustical thermometer for use in the particular environment of interest. While the development of the thermometer was directly aimed at the solution of problems associated with a nuclear and carbonaceous environment, a number of observations are presented that should be pertinent to acoustical thermometer design in general.