Document: NUREG-0800
Document ID: 3b0de11f-324e-46dc-af64-d19d4acbef93
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12353A357.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.3
CFR Part: 
CFR Title: 

Content:
all of the criteria presented in NUREG-1061 related to the ISM method must be followed. In lieu of the response spectrum approach, time histories of support motions may be used as input excitations to the subsystems. The time history approach is considered to provide more realistic results as compared to the USM or ISM methods. 10. Use of Equivalent Vertical Static Factors. The acceptance criteria provided in SRP Section 3.7.2, subsection II.10, are applicable. 11. Torsional Effects of Eccentric Masses. For seismic Category I subsystems, when the torsional effect of an eccentric mass is judged to be significant, the eccentric mass and its eccentricity should be included in the mathematical model. The criteria for judging the significance will be reviewed on a case-by-case basis. 12. Seismic Category I Buried Piping, Conduits, and Tunnels. For seismic Category I buried piping, conduits, tunnels, and any other subsystems, the following items should be considered in the analysis: A. Two types of ground shaking-induced loadings must be considered for design. i. Relative deformations imposed by seismic waves traveling through the surrounding soil or by differential deformations between the soil and anchor points. ii. Lateral earth pressures and ground-water effects acting on structures.