Issue 21: Vibration Qualification of Equipment

DESCRIPTION

This issue originated from NUREG-0572[1] where the ACRS identified vibration-induced equipment failures

resulting from various loading conditions; it was later included in the initial list[2] of new issues that were identified for prioritization. Since the identification of this issue, the staff has addressed vibration-induced equipment failures resulting from a number of sources, e.g., flow-induced vibration (Issue 7), dynamic water hammer loads (Issue A-1), safety relief valve loads (Issue A-8), asymmetric loads (Issue A-2), and seismic loads. These issues are discussed in Sections 2 and 3 of this report.

The seismic loads and their resulting vibration effects on equipment fragility and operability were addressed in the following issues: A-40, "Seismic Design Criteria"; A-41, "Long-Term Seismic Program"; A-46, "Seismic Qualification of Equipment in Operating Plants"; B-24, "Seismic Qualification of Electrical and Mechanical Components"; and B-52, "Fuel Assembly Seismic and LOCA Responses." Other issues that address potential vibration-induced problems include C-12, "Primary System Vibration Assessment," and B-73, "Monitoring for Excessive Vibration Inside the Reactor Pressure Vessel."

It is evident from the above issues that vibration-related problems can arise from many sources and no single, simple, overall solution is appropriate for the broad spectrum of problems. However, since the ACRS identified

this issue, the staff revised the vibration qualification guidance in SRP[3] Sections 3.9.2 and 3.10 (see Issue

B-24). In addition, the above issues addressed specific vibration problems that were handled by the staff on a case-by-case basis.

CONCLUSION

Based on the actions identified above, the original ACRS concerns were addressed by the SRP[4] revisions and the related issues that were resolved on a case-by-case basis. Thus, this issue was DROPPED as a separate issue.