Document: NUREG-0800
Document ID: 73dc4705-6dff-4f44-87ee-2a6f76cc6536
Document Type: srp
Title: OTHER SEISMIC CATEGORY I STRUCTURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1319/ML13198A258.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.4
CFR Part: 
CFR Title: 

Content:
/FEM analysis model. This is a general approach that is appropriate under the linear elastic or equivalent-linear elastic strain assumption and may address some of the issues discussed above. However, a careful review is still needed to ensure the validity of the modeling for this type of application. For example, the computed pressures may be overestimated in the upper soil layers near the surface. Also, the strain iterated soil profiles utilized in typical SSI analysis may not be consistent with the range of strains expected in the backfill soil adjacent to the walls. 3.8.4-41 Revision 4 – September 2013 Best estimate, lower bound, and upper bound soil properties should be considered in the second method if the SSI analysis performed in accordance with SRP Section 3.7.2 includes those soil cases. Hydrodynamic effects on dynamic soil pressures are difficult to estimate accurately but are generally not a concern except for backfill soils with high permeability. In most design situations where saturated conditions exist, it is sufficient to compute the effects of ground water on dynamic soil pressures on the basis of saturated unit soil weight. APPENDIX D 1. Revised Introduction section to include guidance on quality assurance and periodic condition monitoring. See item 3 below for the technical rationale for this change. 2. Revised Item 3, “Seismic and Impact Loads” to enhance guidance on seismic analysis of racks and fuel assemblies. See item 3 below for the technical rationale for this change. 3. Revised Item 4, “Loads and Load Combinations” to clarify the guidance for applicable design loads and the combinations for these loads. The technical rationale for this change is as follows. In accordance with Appendix D to SRP Section 3.8.4, the staff has requested information from DC and COL applicants regarding the ability of spent fuel assemblies to withstand the loads imparted on them during a SSE. As indicated in Appendix D to SRP Section 3.8.4, the