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:
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, plating thicknesses, and other design parameters, when changed, will affect the vibration and alternating stress response of a structure. Such changes need to be captured in updated vibration and alternating stress calculations, and checked against acceptance limits. To ensure optimal choice of sensor locations and orientations when instrumenting reactor internals or other structures for monitoring during pre-operational and start-up tests, the instrument locations need to be based on the results of structural modeling and vibration analysis using as-built specifications. To minimize measurement uncertainty, accelerometers need to be placed at or near predicted peak response locations, and strain gages need to be placed at or near locations with predicted minimum gradients in strain. Coherence needs to be maximized between sensor and critical response locations, such as welds and other stress concentration locations. The anticipated structural or hydro-acoustic vibratory response that is appropriate to each of the sensor locations for steady-state and anticipated transient preoperational and startup test conditions needs to be determined. 2.2 Vibration and Stress Measurement Program The applicant or licensee should develop and implement a vibration measurement program to verify the structural integrity of reactor internals, determine the margin of safety associated with DG-1323, Page 28 steady-state and anticipated transient conditions for normal operation, and confirm the results of the vibration analysis. For SSCs with no prior history of adverse effects because of FIV, AR, AIV, or MIV; and which have been shown by analysis (using acceptable methods from Section C.2.1) to have an acceptable margin of safety against such effects, no instrumentation on the SSC or