Fuel element reliability is still a priority in the modern nuclear power industry. The manufacturers have programs for achieving defect-free operation of fuel. The quality control programs provide for, as a rule, quality control of the finished product at the factory and detailed examination of irradiated fuel assemblies for the purpose of revealing unsealed jackets. In the present paper, we analyze the possibility of using the method of acoustic spectroscopy for investigating the parameters of the gaseous medium in reactor fuel elements. The acoustic method was developed in an earlier work by the authors, and tests suggested the possibility of using an acoustic thermometer in a thermophysical method for investigating the parameters of the gas in reactor fuel elements. The results of this investigation demonstrated that the combination of acoustic spectroscopy and the thermophysical method described herein is adequate for measuring the gas pressure in fuel elements when monitoring the purity of helium during the manufacturing process or for investigations of the composition of the gaseous fission products in irradiated fuel elements.