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:
n forces like coolant recirculation pump frequencies and the flow path configuration should be evaluated. Any frequency coincidence between the pump blade passing frequency and the natural frequencies of the internal structures should be identified and supplemented with error and uncertainty analysis. (vi) Acceptance criteria should be established for allowable responses and for the location of vibration sensors. Such criteria relate to the code-allowable stresses, strains, and limits of deflection established to preclude loss of function of the reactor core structures and fuel assemblies. B. The forcing functions should account for the effects of transient flow conditions and the frequency content. Any potential amplification of a forcing function caused by self-excitation or “lock-in” of a flow instability with a structural or acoustic resonance should be clearly quantified (See RG 1.20, Section C.2.1.3 for more guidance on self-excited flow instabilities). Acceptable methods for formulating forcing functions for vibration prediction include the following: (i) Analytical method: based on standard hydrodynamic theory, the governing differential equations for vibratory motions should be developed and solutions obtained with appropriate boundary conditions and parameters. This method is acceptable where the geometry along the fluid flow paths is mathematically tractable. (ii) Test-analysis combination method: based on data obtained from plant or scale model tests (e.g., velocity or pressure distribution data), forcing functions should be formulated to include the effects of complex flow path configurations and wide variations of pressure distributions. The suitability of any approach used to define forcing functions should be assessed with expected bias errors and uncertainties of the selected approach. In addition to direct measurements in nuclear power plants, the following approaches may be used to formulate the forcing functions. (1) Scale Model Tests (SMTs):