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:
er uprate license amendment request) or planned major plant modifications (e.g., replacement of a steam generator at a PWR nuclear power plant). The staff reviews the program established by applicants and licensees for analyzing potential adverse flow effects on plant components and the flow-induced vibration (FIV) startup test program, including monitoring of plant data, conducting walkdowns, and inspecting components during power ascension and operation at full licensed power conditions to verify that adverse flow effects do not occur. As adverse flow effects in nuclear power plants caused by flow-excited acoustic and structural resonances are sensitive to minor changes in arrangement, design, size, and operating conditions, even applications submitted for minor modifications in non-prototype plants must include rigorous assessments of the potential for such adverse effects. A nuclear power plant nearly identical to another can experience significant such adverse flow effects as valve and steam dryer failures while the other does not. Small changes in operating condition can magnify a small adverse flow effect substantially, leading to structural failures. Regulatory Guide (RG) 1.20 offers specific guidance for these assessments from both analyses and measurements. The following is a summary of the approach to be used by the staff in reviewing the consideration by applicants and licensees of potential adverse flow effects on nuclear power plant systems and components depending on the applicable BWR or PWR design. Additional details of the evaluation procedure and acceptance criteria are outlined in SRP Section 3.9.2 and RG 1.20. 1. Pressure Fluctuations and Vibration in Plant Systems. An applicant to construct and operate a nuclear power plant and a licensee of an 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