MAIN STEAM LINE CONSTANT SUPPORT VIBRATION MONITORING

摘要

Palo Verde Nuclear Generating Station (PVNGS) experienced multiple failures of the constant supports attached to the main steam lines (MSLs) over a period of several years. The continued failures presented a need to instrument the MSL piping and supports, such that monitoring data could be collected in support of a cause determination and problem resolution effort. Extensive data acquisition was performed, including several revisions to the instrumentation configuration in different units at PVNGS by Arizona Public Service (APS) and Structural Integrity Associates, Inc. (SI). Ultimately, no single source of failure was identified, as several potential contributors were uncovered. Modifications were implemented to mitigate the issues, and the instrumentation was used to verify their effectiveness. No further failures have occurred for the modified configuration.