Document: NUREG-0800
Document ID: 81a2e18b-7311-4c4e-822e-8dfe1b0ba7aa
Document Type: srp
Title: REACTOR PRESSURE VESSEL INTERNALS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0702/ML070230009.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.5
CFR Part: 
CFR Title: 

Content:
operating nuclear power plant proposing a power uprate license amendment or a major plant modification (e.g., a PWR steam generator replacement) is expected to determine the pressure fluctuations and vibration in the applicable plant systems under flow conditions up to and including the full operating power level. The pressure fluctuations and vibration can come from various excitation mechanisms like instabilities of separated flows, FIVs, and flow-excited acoustic resonances under the plant system fluid flow conditions. The applicant/licensee is expected to justify the method for determining pressure fluctuations and vibration in plant systems. Experience indicates that computational fluid dynamics (CFD) analyses might not provide sufficient quantitative information about unsteady pressure loading without supplemental analyses. Scale model testing and analysis can evaluate potential adverse flow effects, including hydrodynamic and acoustic pressure loading, and verify the pressure loading results from CFD analyses and the supplemental analyses where the bias error and random uncertainties are properly addressed. Subsections II.3 and II.4 of SRP Section 3.9.2 state specific acceptance criteria and review procedures for methods for evaluating applicable plant systems and components, including dynamic analysis methodology, CFD simulations, scale model testing, and plant startup testing. The applicant/licensee is expected to address possible flow-excited acoustic resonances and FIVs with the potential to damage plant piping and components (like the steam dryer) by modifications, if necessary, to reduce 3.9.5-13 Revision 3 - March 2007 the amplitudes of the acoustic resonances and vibrations. Licensees of operating nuclear power plants are expected to obtain plant-specific data to confirm the scale model testing, structural and acoustic analysis, and CFD results (as applicable) for pressure fluctuations and vibration prior to submitting a power uprate request or