Document: NUREG-0800
Document ID: 8b98402f-b225-4b85-948c-c6f2a4cb5e09
Document Type: srp
Title: POTENTIAL DAM FAILURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070242.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.4
CFR Part: 
CFR Title: 

Content:
ews of cases for which detailed potential dam failure analyses were made during the CP or early site permit review, the CP-stage earlier conclusions will be referenced. In addition, any further review done to reaffirm the 19 maximum or minimum water levels based on any new information will be described and the results and conclusions stated. Sample statements for reviews follow: The staff concludes that the plant design flood elevation, at plant grade of 50 feet 15 m (50 ft) above mean sea level (MSL), is acceptable and meets the requirements of 20 General Design Criterion 2; 10 CFR Part 100; and 10 CFR Part 100, Appendix A, with respect to potential hazards due to dam failure floods. This conclusion is based on the following evaluation. The distance (more than 300 miles 480 km (300 mi)) to upstream reservoirs of 21 appreciable size is such that the staff assessment leads to the conclusion that their arbitrarily assumed failure, under postulated combinations of floods and earthquakes of the severity discussed in Regulatory Guide 1.59, would not constitute a threat to the plant. Dam failure-caused "worst case" floods were evaluated by the applicant based upon failures with consideration of only the location and sizes of upstream impoundments, and not on inherent capability of such structures to resist earthquakes, volcanic activity, and severe landslide-induced floods. The most severe flood of this kind was estimated based upon an assumed catastrophic failure of Dam A some 420 miles 680 km (420 mi)22 upstream. The peak flow at the site from such a flood was estimated to be 3,000,000 cfs 85,000 m /s (3,000,000 cfs). This flow is estimated to occur about 2 days after the dam 3 23 failure and reach elevation 41 feet 12-m (41-ft) MSL, 9 feet 3 m (9 ft) below plant 24 25 grade. A volcanically induced flood was assumed to cause a domino-type failure of the three dams on the tributary B River from a volcanic eruption of Mt. D. The evaluation indicated such an event could