Document: NRC Regulatory Guide
Document ID: 0b3f08e9-b342-468d-a869-a00f19278ecb
Document Type: regulatory_guide
Title: Normal Water Level and Discharge at Nuclear Power Plants
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740143.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.135
CFR Part: 
CFR Title: 

Content:
U.S. NUCLEAR REGULATORY COMMISSION 4 REGULATORY GUIDE , OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 1.135 NORMAL WATER LEVEL AND DISCHARGE AT NUCLEAR POWER PLANTS A. INTRODUCTION General Design Criterion 2, "Design Bases for Protection Against Natural Phenomena," of Appen dix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50, "Licensing of Produc tion and Utilization Facilities," requires that struc tures, systems, and components important to safety be designed to withstand the effects of natural phenomena such as floods, tsunami, and seiches without loss of capability to perform their safety functions. Criterion 2 also requires that design bases for these structures, systems, and components reflect: 1. Appropriate consideration of the most severe of the natural phenomena that have been historically reported for the site and surrounding region, with sufficient margin for the limited accuracy and quan tity of the historical data and the period of time in which the data have been accumulated, 2. Appropriate combinations of the effects,,of n•6 mal and accident conditions with the effectsof the'. natural phenomena, and ... 3. The importance of the safety furfons i6 be per formed. Paragraph 100.1 r bftOCFR Part 100, "Reactor Site Criteria." requi t'• [k., ysical characteristics of the site, Inc] I ei lo&g' meteorology, geology, and hydro y, b k e-into account in determining the ac . ta 'ty o ',site for a nuclear power reactor. Th uide sets forth methods acceptable to the NRC f for determining normal ground and sur face wat r levels and surface water discharges for use in analyses of the. effect of design basis natural and accidental events on structures and systems at nuclear power plants. This guide also suggests data sources and acceptable methods for determining such water levels and discharges. B. DISCUSSION Some structures and systems .. 'Mnost nuclear power plants are continually suif o uctuating live loads that result from variions