Document: NRC Regulatory Guide
Document ID: c7b1689b-ff17-4083-9fb1-f91b6965ea1a
Document Type: regulatory_guide
Title: Design Basis Floods for Nuclear Power Plants + HISTORY - HISTORY 02/2022 – DG-1290 , Proposed Revision 3 09/2014 – Periodic Review of Revision 2 – Revise 07/1980 – Errata to Revision 2 07/2024 – DG-1290 Revision 1 (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740388.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.59
CFR Part: 
CFR Title: 

Content:
profile along the traverse line was determined by roughly averaging the topography of cross sections perpendicular to the traverse line and extending a maximum of 5 nautical miles to either side. The 10-mile-wide cross sections were narrowed uniformly to zero at the selected site starting 10 nautical miles from shore. It was assumed that the peak of the PMS coincided with the 10% ex ceedance high spring tide' plus initial rise.' Slightly different procedures were used for postulating the traverse lines and profiles for the Crystal River and St. Lucie determinations. In each case the maximum water level resulted from use of the high translation speed for the hur ricane in combination with the large radius to max imum wind as defined in Reference 5. Detailed data for the computed PMS values are shown in Tables C.1 through C.20. Ocean-bed profile data for Pass Christian, Crystal River, St. Lucie, Chesapeake Bay Mouth, and Hampton Beach are shown in Table C.21. The water levels resulting from these computations are open-coast stillwater levels upon which waves and wave runup should be superimposed. C.3.2 Use of Data In Estimating PMS Estimates of the PMS stillwater level at open-coast sites other than those shown in Tables C.1 through C.21 and on Figures C.1 and C.2 may be obtained as follows: 'The 10% exceedance high spring tide is the predicted maximum monthly astronomical tide exceeded by 10%.of the predicted max imum monthly astronomical tides over a 21-year period. 'Initial rise (also called forerunner or sea level anomaly) is an anomalous departure of the tide level from the predicted axtronomical tide. 1.59-42 C.3.1 Methods Used I I I. Using topographic maps or maps showing soundings, such as the Nautical Charts, determine an ocean bed profile to a depth of 600 ft MLW, using the methods outlined above. Compare this profile with the profiles of the locations shown in Tables C.2 through C.21. With particular emphasis on shallow water depths, select the location or