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 existing plants; However, it is not required for non-prototypes except that segments of an analysis (in particular, assessments of any potential adverse flow effects) may be necessary if there are deviations from the prototype internals design or operating conditions or if the non-prototype is based on a conditional prototype which has experienced problems from adverse flow effects. If the reactor internal structures are a non-prototype design, the applicant should refer to the results of tests and analyses for the prototype reactor and give a brief summary of the results. A more detailed summary of results of assessment of the potential of any adverse flow effects also should be given. A. The results of vibration and stress calculations should consist of the following: (i) Dynamic responses to operating transients at critical locations of the internal structures should be determined and, in particular, at the locations where vibration sensors will be mounted on the reactor internals. For each location, the maximum response, the modal contribution to the total response, (in case of cyclic or resonant behavior), and the response causing the maximum stress amplitude should be calculated. (ii) The damping factors for different modes should be properly selected and substantiated. In prior submissions, utilities have cited NRC damping guidance for very low frequency seismic analyses as justification for high damping factors for mid-to-high frequency analyses. RG 1.20 corrects this guidance and requires that damping factors used in structural dynamic modeling be based on mid- to high-frequency measurements or rigorous analyses conducted on structures typical of the reactor internal structure modeled. (iii) The dynamic properties of internal structures, including the natural frequencies and shapes of the dominant modes, should be characterized. In analyses of a component structural element basis, the presence of dynamic coupling among component structure elements