Document: NUREG-0800
Document ID: cefc1d6c-e171-41f0-bdf3-b5d7ef6a7f43
Document Type: srp
Title: MISSILES GENERATED BY TORNADOES AND EXTREME WINDS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070380174.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.4
CFR Part: 
CFR Title: 

Content:
e effects of missiles, from events and conditions outside the nuclear unit. Tornadoes are dynamic events originating outside the nuclear unit; therefore, this criterion is applicable to the assessment of any missiles generated by tornadoes. For safety considerations, nuclear power plant design must consider the impact of direct action of tornado wind and the moving ambient pressure field, as well as the impact of tornado-generated missiles. Protection from a spectrum of missiles exemplified by missiles with critical characteristics provides assurance that the necessary SSCs will be available to mitigate the potential effects of a tornado on plant safety. III. REVIEW PROCEDURES The reviewer will select material from the procedures described below, as may be appropriate for a particular case. These review procedures are based on the identified SRP acceptance criteria. For deviations from these acceptance criteria, the staff should review the applicant’s evaluation of how the proposed alternatives provide an acceptable method of complying with the relevant NRC requirements identified in Subsection II. 1. The SAR is reviewed for the identification of the design-basis natural phenomena that could possibly generate missiles. Postulated missiles are reviewed for proper characterization. 2. RG 1.76 provides guidance on the definition and characterization of the design-basis tornado as discussed in Subsection II. 3. The design-basis natural phenomena for the site are reviewed with respect to the potential for missile generation. For phenomena with greater potential for missile generation than the design-basis tornado (i.e., the probability per year of damage to the total of all SSCs important to safety is 10-7 per year or greater), appropriate design-basis missiles are proposed. 4. All plants are required to be designed to protect safety-related equipment against damage from missiles which might be generated by the design-basis tornado for that plant. The reviewer verifies