Document: NUREG-0800
Document ID: 9cdf4eb8-90c4-435e-84a4-d23c09056921
Document Type: srp
Title: STABILITY OF SUBSURFACE MATERIALS AND FOUNDATIONS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070268.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.4
CFR Part: 
CFR Title: 

Content:
/sec), respectively. Zone 1 60 61 ranges in thickness from less than 6 meters (20 feet) to more than 15 meters 62 (50 feet).63 (b) Zone 2 consists of moderately weathered slate and varies from 5 to 18 meters (15 to 60 feet) thick. P and S wave velocities generally exceed 2000 m/sec 64 (6500 ft/sec) and 800 m/sec (2500 ft/sec), respectively. 65 66 (c) Zone 3 contains slightly weathered to unweathered slate and is encountered at depths of 18 to 27 meters (60 to 90 ft) below ground surface. 67 The-site area will be leveled to about elevation +119 meters (+390 feet) msl, and 68 containments will be founded on a 3 meter (10 foot) thick, reinforced concrete mat on 69 slightly weathered slate or fill concrete over slightly weathered slate. The reactor service building between the reactors and the control building will be on mats at elevation +117 meters (+385 feet) msl on compacted structural fill resting on slightly to 70 moderately weathered rock. The turbine generators will be founded on compacted structural fill over moderately weathered rock at elevation +116 meters (+380 feet) msl. 71 The diesel generator building, reactor plant component air-cooled heat exchanger enclosures, and the CACS air-cooled heat exchanger will be founded on either individual concrete footings or continuous footings (grade beams) at +117 meters (+385 feet) msl, 72 on compacted structural fill over moderately weathered slate. Allowable bearing capacities from laboratory tests and field plate tests for Zone 1, Zone 2, and Zone 3 materials are 40, 100, and 240 metric tons per square meter (4, 10, and 25 tons per square foot), respectively. All piping will be entrenched and bedded in moderately to severely 73 weathered slate. Settlement and differential settlement of safety-related facilities has been estimated to be less than 2.5 centimeters (1 inch).74 The applicant states that severely weathered or soft zones of rock will be excavated and replaced with lean concrete. This procedure will also