Document: NRC Regulatory Guide
Document ID: ad61f8a3-1cce-4446-9542-dcdda55c1ec6
Document Type: regulatory_guide
Title: Comprehensive Vibration Assessment Program for Reactor Internals During Preoperational and Initial Startup Testing + HISTORY - HISTORY 07/2015 – DG-1323 , Proposed Revision 4 03/2013 – Periodic Review of Revision 3 – No Issues Identified 11/2006 – DG-1163 , Proposed Revision 3 (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1508/ML15083A390.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.20
CFR Part: 
CFR Title: 

Content:
hat minor design or operating changes from the valid prototype might increase substantially the vibration and alternating stresses, not only for the components with modified design, but also for other components that might appear unrelated to the design modifications. As an example, a small increase in the length of the SRV standpipes can trigger acoustic resonance in the MSLs and thereby substantially increase the alternating loading on the steam dryer of BWRs. Change in the RRP speed is another example, where the VPF may shift to align with a resonance. If these issues exist, the applicant or licensee should address them in the CVAP. 3.2 Vibration Measurement Program The applicant or licensee should develop and perform a vibration measurement program for limited prototype reactor internals during preoperational and startup testing. Generally, the vibration measurements program would be confined to the limited prototype internals, but if the vibration analysis indicates possible initiation of vibration feedback excitation mechanisms because of design modifications of the limited prototypes, or if the applicable valid prototype is operating at conditions close to those at which vibration feedback excitation mechanisms can be initiated, the vibration measurement program needs to be expanded to include other reactor internals that might be adversely affected by any possible self-excited vibration mechanisms. Sufficient and appropriate instrumentation needs to be applied to verify that the vibratory response of the limited prototype reactor internals is consistent with the vibration analysis results, test acceptance criteria, and vibratory response observed in the valid prototype. The vibration measurement program for a limited prototype should follow the general guidelines for the vibration measurement program delineated in Section C.2.2 of this regulatory guide for prototype reactor internals. DG-1323, Page 38 If the measured responses are found to be significantly