Document: NUREG-0800
Document ID: fbcd53f5-fb4a-436f-9443-ef89f47e42cc
Document Type: srp
Title: SEISMIC AND DYNAMIC QUALIFICATION OF MECHANICAL AND ELECTRICAL
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1422/ML14227A631.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.10
CFR Part: 
CFR Title: 

Content:
t is adequately represented by one mode, or in the case of structural integrity assurance, the input has enough intensity and duration to produce sufficiently high levels of stress for such assurance. Components that have been previously tested to IEEE Std 344-1971 should be reevaluated to justify the appropriateness of the input motion used and requalified if necessary. vi. For the seismic and dynamic portion of the loads, the test input motion should be applied to one vertical axis and one principal horizontal axis (or two orthogonal horizontal axes) simultaneously, unless it can be demonstrated that the equipment response in the vertical direction is not sensitive to the vibratory motion in the horizontal direction, and vice versa. The time phasing of the inputs in the vertical and horizontal directions must be such that a purely rectilinear resultant input is avoided. An acceptable alternative is to test with vertical and horizontal inputs in phase, and then repeat the test with inputs 180 degrees out of phase. In addition, the test must be repeated with the equipment rotated 90 degrees horizontally if this alternative is selected. Components that have been previously tested to IEEE Std. 344-1971 should be requalified using biaxial test input motions unless the applicant provides justification for using a single-axis test input motion. vii. Dynamic coupling between the equipment and related systems, if any, such as connected piping and other mechanical components, should be considered. 3.10-8 Draft Revision 4 – August 2015 viii. The fixture design should simulate the actual service mounting and should not cause any extraneous dynamic coupling to the test item. ix. For pumps and valves, the loads imposed by the attached piping should be considered. To ensure functionality under combined loadings, the stresses resulting from the applied test loads should envelop the specified service stress limit for the intended function of the component. Stresses in valve