Document: NUREG-0800
Document ID: 6b7eddf4-f7ce-4821-9f11-e37070221e57
Document Type: srp
Title: DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, STRUCTURES, AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1613/ML16133A418.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.2
CFR Part: 
CFR Title: 

Content:
g (SMT), and response deduction methods) should be assessed. Any forcing function estimates caused by such adverse flow effects as flow instabilities over standoff pipe openings are reviewed to ensure they are adequate and bounding. (i) If SMT is used to support the dynamic analysis, the review process should include the following: (1) Any deviations between the model and the plant parameters should be assessed in detail. Such parameters include Reynolds number, acoustic attenuation, fluid-elastic parameter and small details of the model geometry. 3.9.2-7 Revision 4 – March 2017 (2) The effects of transient test conditions on the speed of sound and the accuracy of pressure and flow velocity measurements. (3) The procedure used to determine the amplitudes of acoustic and mechanical resonances and their expected amplification with power level (sometimes referred to as a bump-up factor [BUF]). This includes validation of the SMT results which are used to develop the forcing functions. (ii) If CFD models are used to develop unsteady forcing functions, or compute the distribution of flow velocity which is used to develop the forcing functions, the following items should be reviewed as applicable: (1) The procedure for validating the CFD code used to estimate the forcing functions. (2) The model grid size and the computation time step. (3) The appropriateness of the simulated flow conditions. (4) All parameters and simplifying assumptions that might affect the CFD results and the computed forcing functions, including fluid properties, correlation length and phase of fluid forces, fluid- acoustic or fluid-structure interaction, and accuracy of the fluid domain model. (iii) In recent BWR extended power uprate (EPU) requests, licensees have employed inverse methods to estimate the forcing functions on steam dryers. This approach is aided by measurements of fluctuating pressures either (a) on dryer surfaces, or (b) within the MSLs connected to the RPV and/or (c) surface