Document: NUREG-0800
Document ID: a0558f18-a0e8-4971-b9bc-5909d213124e
Document Type: srp
Title: (Hydrosphere) requires identification of the hydrologic characteristics of streams, lakes
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070238.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.1.2
CFR Part: 
CFR Title: 

Content:
f natural phenomena such as earthquake, tornado, hurricane, flood, tsunami, and seiche without loss of capability to perform their safety functions. The GDC further specifies that the design bases for these structures, systems, and components shall reflect the following: a. Appropriate consideration of the most severe of the natural phenomena that have been historically reported for the site and surrounding area, with sufficient margin for the limited accuracy, quantity, and time period in which the historical data have been accumulated; b. Appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena; and c. The importance of the safety functions to be performed. The first specification was adopted in recognition of the relatively short history available for severe natural phenomena on the North American continent and, as a result, the potential for underestimating the severity of such events, based on probabilistic considerations only. This problem can be avoided by using a deterministic approach to assess design basis events. Such an approach will account for the practical physical limitations of natural phenomena to contribute to the severity of a given event. This criterion is applicable to SRP Section 2.4.1 in that it specifies the hydrologic phenomena that must be described in the section. In general terms, it also specifies the level of conservatism that must be used to assess the severity of these phenomena when determining the appropriate design bases for structures, systems, and components important to safety. The latter controls the degree of completeness required in the hydrologic description of the site and region. Meeting the requirements of this criterion provides a level of assurance that structures, systems, and components important to safety have been designed to withstand the most severe natural phenomena likely to occur.7 2. Section 100.10(c) of 10 CFR Part 100 requires that physical