Abstract: A frequency measuring device measures a natural frequency of a reactor jet pump sensing line supported by a sensing line support bracket in a nuclear reactor. The frequency measuring device includes a base member, a sensing line clamp attached to the base member that attaches to the sensing line support bracket, and at least one actuator attached to the base member. The actuator is positioned relative to the sensing line when the sensing line clamp is attached to the sensing line so that the actuator can strike the sensing line. A proximity probe attached to the base member measures vibration of the sensing line and outputs a vibration signal. A processor receives and processes the vibration signal from the proximity probe to determine the natural frequency.

Abstract: A frequency measuring device measures a natural frequency of a reactor jet pump sensing line supported by a sensing line support bracket in a nuclear reactor. The frequency measuring device includes a base member, a sensing line clamp attached to the base member that attaches to the sensing line support bracket, and at least one actuator attached to the base member. The actuator is positioned relative to the sensing line when the sensing line clamp is attached to the sensing line so that the actuator can strike the sensing line. A proximity probe attached to the base member measures vibration of the sensing line and outputs a vibration signal. A processor receives and processes the vibration signal from the proximity probe to determine the natural frequency.

Abstract: In the test of a casing enclosed shaft and impeller for structural integrity against defects such as loose bolts or cracks, an apparatus and process is disclosed which enables in-situ testing to occur within a casing. A model of the shaft and impeller, such as a spare part, is suspended so as to simulate the in casing boundary conditions and is then vibrated. Vibration or "ringing" occurs through a normally exposed end of the shaft far removed from suspected defects. A cap can be used to suspend the shaft and impeller or rotor. Vibration is imparted to the remote end of the shaft, sometimes on the cap, with an instrumented hammer blow of specific duration and known energy. Measurement and resolution of the resultant vibrations and energy dissipating damping occurs by mounting accelerometers to the remote normally exposed shaft end and recording and playing back the vibrations from the mounted accelerometers through a spectrum analyzer.