Vibrational measurements of line-mounted equipment on the LOFT feedwater system

As part of the NRC/EG and G Equipment Qualification Program, the vibration response of the Loss of Fluid Test (LOFT) feedwater system was monitored to determine spectral acceleration levels typical for line mounted equipment. Accelerometers were placed on the main feedwater pump, three valves, and one piping support. The response of the system was monitored using a two channel analyzer. Measurements were recorded at four power levels as reactor power was increased from the source range to 64% of full power. The resulting spectra show responses up to 3000 Hz. Observations concerning the data were made by computing and evaluating the Fourier transforms for the test. Maximum spectral amplitudes of 0.05 to 0.4 gs rms were recorded. No correlation of response level vs. feedwater flowrate was detected. Examples of Fourier spectra of the feedwater system components are included in the paper. These are considered typical of those which would be expected in a nuclear plant auxiliary feedwater system