Abstract: A method and system for fuel rod pressurization and for verifying when pressurization of a fuel rod containing nuclear fuel has taken place. One end of the loaded fuel rod is inserted into a pressure chamber in sealed relation thereto, whereupon the chamber is evacuated to remove the air present. Then the chamber is pressurized with an inert gas. The fuel rod then is drilled to provide an opening in the end of the fuel rod in the chamber, whereupon the rod is pressurized with the inert gas present in the chamber. Acoustic transducers are attached to the fuel rod at predetermined locations externally of the chamber for monitoring any noise which occurs during the pressurization process, which is transmitted through the metal walls of the rod to the transducers. The transducers generate electrical signals which are proportional to the amplitude of the noise sensed and by observing the signals a calibration of the activity going on can be maintained.