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:
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 i ound water levels, discharges -ld a Is isn'treams, or water levels in lakes anid uctures that ex tend below grousd surfac~nto the local ground water aquifer•-(o1ý` 1 # A ifers must withstand the resulting hydftaticýressti'e. Structures that are af fected b1:.zurfhceý*atetdischarges and levels include damss, 6•-.,•a; aters, canals, and intake and dis cl*4e s•c•.cids. In considering the effects of design bas eientsiuch as earthquakes, tornadoes, and hur ricwsnt&;and the effects of design basis accidental e•ffVw, 'ts such as plane crashes, transportation acci "."dents, explosions, fires, and loss-of-coolant accidents (LOCAs), the designer must include in his calcula tions the loads caused by the water level (or dis charge), as well as the load on the structure or system caused by the design basis event being considered. This water level (or discharge) is referred to in this guide as the normal water level (or discharge). Since the design basis events have a very low probability of occurrence, the water level (or dis charge) used in combination with the design basis event need not represent a condition with low Design basis events are those natural events that there is virtually no risk of exceeding, such as the Probable Maximum Hurricane, Safe Shutdown Earthquake, and other natural events of similar low probability of occurrence, and accidental events, such as ex plosions, plane crashes, and fires. USNRC REGULATORY GUIDES Comments should be sent to the Secretary of the Commission. US. Nuclear Regu Regulatory Guides are issued to describe and make available to the public methods latory Commission, Washington. D.C. 20555, Attention. Docketing and Service acceptable to the NRC staff of implementing specific parts of the Commission's Branch. regulations, to