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:
d on the most recent data acquired. Also, corresponding estimates of full-power levels need to be continuously updated using trending analysis. The trending needs to be based on a reasonable number of data points over variable power levels. In the event that a flow, mechanically, or acoustically coupled resonance appears, the trending needs to apply conservative functions to ensure worst-case response at higher power levels is adequately bounded. When using a polynomial trending, a minimum of a squared power law with respect to power should be used. Coupled resonance polynomial orders should be higher than a squared power. If a projected limit is exceeded, more detailed analyses will need to be conducted. (8) End-to-end bias and uncertainties for the overall BWR steam dryer analysis procedure are updated by comparing predicted and measured strains or accelerations at each power level to confirm the conservatism of the predicted stress and vibration. Predicted responses need to be updated using the frequency- dependent end-to-end bias errors and uncertainty values. If the measured sensor data exceed the adjusted predictions, then the bias errors, uncertainty values, and limit curves need to be adjusted to ensure measured sensor responses do not exceed the adjusted predictions. d. Guidance on test duration: The applicant or licensee should specify the planned duration of all testing in normal operating modes to ensure that the testing will subject each critical component to at least 106 cycles of vibration (i.e., computed at the lowest frequency for which the component has a significant structural response) before the final inspection of the reactor internals. e. Guidance on disposition of fuel assemblies: The applicant or licensee should address the disposition of fuel assemblies. Preoperational testing should be performed with the reactor internals important to safety and the fuel assemblies (or dummy assemblies that provide equivalent dynamic mass and flow