Document: NUREG-0800
Document ID: ed40908c-6d5d-42a3-bb9e-fcf4f68dd278
Document Type: srp
Title: FLOODING PROTECTION REQUIREMENTS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340554.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.10
CFR Part: 
CFR Title: 

Content:
n. For OL reviews the findings will indicate the flood protection measures. provided for safety-related facilities, and will indicate the type of technical specifica- tions required to assure that the protection will be in place. If Regulatory Guide 1.59, Position 2, is elected by the applicant, a statement describing lesser design bases will be included in the findings with the staff's conclusion of adequacy. A sample CP-stage statement follows: The staff concludes that the flood protection design of the plant is acceptable and meets'the requirements of 10 CFR.Part 50, §50.55a, GOC 2, and 10 CFR Part 100. This conclusion is based upon the following evaluation: The probable maximum surge produces a maximum calculated stillwater level that is 3.9 feet above the plant grade elevation (583.0 feet). Wave runup associated with the coincident wind wave activity results in calculated flooding levels at safety-related structures that are higher than the stillwater level. Subsequent to our review of the Preliminary Safety Analysis Report, theapplicant proposed'a break- water fronting the plant to attenuate the effects of the probable maximum meteorological event on plant structures. The breakwater will be a rubble mound structure using an armor cover of stone. The toe of the structure will be at 572.0 feet and the crest will be at 583.0 feet. The front (lakeward) slope will.be 2 horizontal to 1 vertical. To determine the design wave for the breakwater, the toe was conservatively assumed to scour 3 feet to elevation 569.0 feet. The maximum significant breaking wave was estimated' to be 12.2 feet during the probable maximum surge. Based on these conditions, the armor layer was designed to be 7.5 feet thick using 3.3-ton to 5-ton stone. Underlayers were'specified as follows: the secondary layer will be 3.5 feet thick with 600-pound to 1000-pound stone; and the filter layer will'be 1.5 feet thick with 30-pound to 50-pound stone. The staff independently evaluated the.proposed