Document: NUREG-0800
Document ID: ce3522a1-5c42-492a-95d7-9087534cf63c
Document Type: srp
Title: STABILITY OF SLOPES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070270.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.5
CFR Part: 
CFR Title: 

Content:
clusion in the SER states that the investigations performed for slope stability studies and dam and dike analyses are adequate to justify the soil and rock characteristics used in the design, and that the design analyses contain margins of safety which adequately demonstrate that natural and manmade slopes will remain stable under SSE conditions and that safety-related earthwork will function reliably. The staff's conclusions regarding the stability of slopes are summarized in the safety evaluation report (SER) or in a supplement to the SER. The following is an example: 44 Both natural and manmade slopes exist at the site. At the plant site, which is located several hundred meters (feet) from the Green Valley and about 85 meters (280 feet) 45 46 above the level of Jones Pond, the slope is relatively gentle for about 75 meters (250 feet) west of the westernmost Category I structures, then steepens, attaining an 47 angle of more than 45 near the bottom of the valley wall. Major structural trends, schistosity, and one of the predominant joint trends are nearly perpendicular to the slope. A second predominant joint set is nearly parallel to the river and dips to the southwest, but no slope movements have apparently affected the valley walls in the vicinity of the site. Seven other joint trends were detected by the applicant. These joint sets are reported to be moderately spaced and discontinuous. The applicant has drilled several exploratory holes and cored others to assess the natural slope characteristics and groundwater regime. Even though the natural slopes are some distance from safety-related plant facilities and slope failures are not obvious safety hazards, the applicant has performed stability analyses of these slopes under safe shutdown earthquake (SSE) conditions. The minimum computed safety factor was 1.6 using conservative slope and material parameters. Manmade earth slopes related to the safety of the plant include excavation cuts for the ultimate heat