Monitoring of core support barrel motion in PWRs using excore detectors

Core Support Barrel (CSB) motion was quantified in a PWR using the following statistical descriptors: cross and auot power spectral density, coherence, and amplitude probability density. A scale factor was calculated for quantifying the CSB motion. We found it necessary to employ two-dimensional geometry complexity for the calculations of the scale factor. The statistical descriptors used for quantifying CSB motion had to be obtained from band-limited signals. The frequency range used for band-limiting was determined from the phase and the coherence between diametrically opposite excore power range monitors.