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
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CFR Title: 

Content:
-prototype” after the inspection of the “prototype” reactor internals following initial startup testing. The applicant/licensee should follow the applicable guidance in this regulatory guide for “prototype,” “limited prototype,” and “non-prototype” reactor internals for the individual reactor units. DG-1323, Page 11 2. CVAP FOR PROTOTYPE REACTOR INTERNALS The CVAP for prototype reactor internals consists of a vibration and stress analysis, vibration measurement, inspection, and correlation of predicted and measured results to demonstrate the acceptable performance of reactor internals important to safety for the full range of flow, temperature, and pressure conditions associated with normal steady-state and anticipated transient operation of the nuclear power plant. As part of the CVAP, applicants designing or proposing to construct and operate a new nuclear power plant, licensees planning to request an EPU for an existing nuclear power plant, and licensees planning a major modification to an existing nuclear power plant should analyze the effects of potential vibration mechanisms that can affect the reactor internals. The following list comprises the main excitation mechanisms that need to be addressed: a. FIV and AR produced by fluid flow across or parallel to structural components. These mechanisms include vibration induced by flow turbulence (turbulent buffeting), acoustic resonance excitation by separated flow instabilities, vibration induced by vortex shedding excitation, and fluid-elastic instability (FEI) (Ref. 6). FIV occurs not only in the lift (or normal to the flow) direction, but also in the drag (or streamwise) direction. Up to this time, predictive analysis and testing of FIV of plant components caused by vortex shedding excitation and FEI focused primarily on structural vibration in the lift direction. However, experiences from nuclear power plants revealed thermowell failure because of streamwise vibration excited by vortex