Document: NUREG-0800
Document ID: 7c104096-d040-463a-a94b-a0af08ab3478
Document Type: srp
Title: DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, STRUCTURES, AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0702/ML070230008.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.2
CFR Part: 
CFR Title: 

Content:
of vibration and stress calculations. The calculated vibration and stress levels in reactor internal structures and in main steam line (MSL) valves are reviewed with their safety margins. The results for structures and components with a history of failures from adverse flow effects (like steam dryers and safety relief valves excited by flow instabilities over the openings of valve standoff pipes) are given greater scrutiny. The dynamic properties of internal structures, including natural frequencies, mode shapes relevant to the vibration and stress response, damping factors, and frequency response functions (FRFs) are reviewed. Any potential adverse flow conditions which lead to self-excited response (where structural and/or acoustic vibration couples to the forcing function, increasing its amplitude) are reviewed with greater scrutiny, particularly for conditions which have led to failures in the past. B. Transient and steady-state flow-induced forcing functions. Forcing functions within the reactor vessel and within the feedwater and steam systems (e.g., those induced by flow around the sampling probes in the feedwater piping and over the standoff pipes of valves in the MSLs are reviewed along with the method(s) for specifying the forcing functions (analytic or numerical tools like computational flow dynamics (CFD) models, test-analysis combination methods like Scale Model Testing, and response deduction methods). Any forcing functions caused by such adverse flow effects as flow instabilities over standoff pipe openings are reviewed with greater scrutiny. C. Methods for obtaining vibration and stress predictions. The procedures for combining the vibration and stress response models (Item 3.A above) with the forcing functions (Item 3.B above) to compute overall vibration and stress response are reviewed. 3.9.2-6 Revision 3 - March 2007 D. Verification of predictions by comparison to test results. The comparisons of predictions and test results are reviewed along