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:
o be used to establish operational limits on monitoring instrumentation to be applied to the structure for in-plant testing (see Section C.2.2). Steam dryer vibration and alternating stress simulation calculations might need additional factors of safety on allowable limits. Additional factors are necessary when partial or no benchmarking of valid prototypes has been performed, or when remote assessment methods are used. An example is using circumferentially oriented strain gages on BWR MSLs to infer acoustic wave amplitudes within the MSLs. The wave amplitudes are commonly used to develop approximate fluctuating pressure loads on steam dryers. However, there might be additional localized forcing functions on a reactor internal which are not detectable at the remote monitoring locations. The additional factor of safety ensures that all loading mechanisms are bounded. There is no set value for this additional factor of safety, and it is assessed on a case-by-case basis depending on the breadth and quality of previously submitted information for similar structures. When on-dryer testing is used to benchmark the design analysis results or monitor vibration and stress, the additional factor of safety is no longer necessary, provided the measurements capture all key vibration and stress peaks. 2.1.4 Preoperational and Testing Analysis The applicant or licensee should summarize the calculated structural and hydro-acoustic responses for preoperational and startup testing conditions, compared to those for normal operation. This summary should address the adequacy of the test simulation to normal operating conditions. Also, the variability in reactor operating parameters can affect flow rates, working fluid mass density, pressures, and other quantities. The applicant/licensee should account for these variations and assess reactor internals and other safety-related components at worst-case operating conditions. As-built components often differ from original designs. Welds,