Exxon Nuclear Company, Inc.

Dan L Robinson

Harry R Deveraux

Dan C Worlton, Deceased

Dan L Worlton, Deceased

Richard K Welty

Nuclear reactor fuel rod leakage is determined by measurement of vibrational characteristics of a resilient, flexible means sealed within the upper end caps of the fuel elements. The flexible means, which is preferably a metallic diaphragm, is set into motion by the impact of an internal metal rod which is operated by an external magnetic field, thereby permitting an indication of the pressure inside a fuel element without disturbing the welded assembly. The metal rod is activated and the vibration measurements are made through the use of a special tool which fits near the end cap of the fuel element to be tested.

Detection of fuel rod leakage

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. A pressure transducer is connected with the pressure chamber for monitoring the status of the pressure in the chamber and providing an output signal which is proportional thereto. The acoustic and pressure signals are processed through appropriate electronic circuitry and recorded in analog and/or digital fashion for providing a comparative indication as to the status of when the necessary steps and activities for pressurization of the fuel rod have been accomplished.

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Richland, WA, United States of America

Dan L Robinson