Document: NUREG-0800
Document ID: 73747cf4-ff95-449b-b6b0-53dc0755b9e0
Document Type: srp
Title: OTHER SEISMIC CATEGORY I STRUCTURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12353A382.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.4
CFR Part: 
CFR Title: 

Content:
zed 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 Draft Revision 4 – December 2012 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 safe shutdown earthquake (SSE). As indicated in Appendix D to SRP Section 3.8.4, the acceptance criteria related to the design of spent fuel racks requires, in part, that the structural integrity of the spent fuel contained within the racks be maintained during a seismic event. The spent fuel racks are designed as seismic Category I to protect the contained spent fuel assemblies. In addition, it is necessary to evaluate the spent fuel assemblies to ensure that when subject to ASME Service Level D loads,