Document: NUREG-0800
Document ID: fce5c014-cdea-4bf2-83f9-535d051f0f3b
Document Type: srp
Title: MISSILES GENERATED BY NATURAL PHENOMENA
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070375.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.4
CFR Part: 
CFR Title: 

Content:
ppropriate and is conservative. Designing a nuclear power plant to withstand the design-basis maximum tornado wind speed ensures that SSC important to safety will be capable of performing their safety functions and that there will be no undue risk to the health and safety of the public in the event of tornado conditions. 2. GDC 4 establishes requirements regarding the ability of SSC important to safety to be protected from dynamic effects, including the effects of missiles, from events and conditions outside the nuclear unit. Natural phenomena such as tornados are dynamic events originating outside the nuclear unit, therefore, this criterion applies directly to the assessment of any missiles generated by such events. The selection of SSC to be protected is based upon the methods of Regulatory Guide 1.117 and maintaining offsite exposures below an appropriate fraction of the offsite dose guidelines of 10 CFR Part 100. Basing the limits upon an appropriate fraction ensures protection for those tornado events that are not as severe as the design-basis tornado but have a higher probability of occurrence. The application of Regulatory Guide 1.117 provides a method for defining those SSC that should be protected from the effects of a design-basis tornado without losing the capability to perform their safety functions. Protecting SSC important to safety from missiles generated by natural phenomena will ensure that they will be capable of performing their safety functions under severe dynamic conditions and ensuring there will be no undue risk to the health and safety of the public in the event of such conditions. III. REVIEW PROCEDURES The procedures below are used during the construction permit (CP) review to determine that the design criteria and bases and the preliminary design as set forth in the preliminary safety analysis report meet the acceptance criteria given in subsection II. For review of operating license (OL) applications, the procedures are utilized to