Document: NUREG-0800
Document ID: 5269bfff-df41-4f7b-9872-4f4ce819a504
Document Type: srp
Title: PROBABLE MAXIMUM TSUNAMI FLOODING
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340543.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.6
CFR Part: 
CFR Title: 

Content:
ty of specific design bases, and the acceptability of design provisions. A sample statement for a CP review follows: The staff concludes that the plant design is acceptable with respect to its ability to withstand the effects of tsunami. It therefore meets the tsunami design requirements of GDC 2, 10 CFR Part 100, and 10 CFR Part 100, Appendix A. This conclusion is based on the follow- ing analysis. Analyses of tsunamic effects from local and distant generators were performed by the applicant at the staff's direction. The design tsunami results from a magnitude 8.7 earthquake in the Aleutian Trench. A finite difference numerical model was used to analyze tsunami generation and propagation to the continental shelf. Results of this computation were used in a nearshore model to calculate tsunami runup and drawdown. Including the effects of high and low tides of annual occurrence, the maximum tsunami runup and drawdown are esti- mated as +24.5 feet MLLW and -13.4 feet MLLW, respectively. Wind waves of annual severity were assumed coincident with the tsunami. Plant grade at elevation +55 MLLW is well above the tsunami flood level. The maximum wave runup, at the intake pumphouse, was esti- mated as +31.2 feet MLLW which is 3.8 feet below the design flood level of +35 feet MLLW. The maximum drawdown, at the location of the inshore intake, was estimated as -21.3 feet MLLW. The intake is designed to be able to draw water down to -30 feet MLLW and will therefore not be affected by low water due to tsunami drawdown. V. IMPLEMENTATION The following is intended to provide guidance to applicants and licensees regard- ing the NRC staff's plans for using this SRP section. Except in those cases in which the applicant proposes an acceptable alternative method for complying with specified portions of the Commission's regulations, the method described herein will be used by the staff in its evaluation of con- formance with Commission regulations. Implementation schedules for