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:
ed in Regulatory Guide 1.117), due to 22 a specific design basis natural phenomena capable of generating missiles is estimated. If this probability is greater than the acceptable probability stated in Regulatory Guide 1.117, then specific design provisions must be provided to reduce the estimate of damage probability to an allowable level.23 3. If this probability is greater than the acceptable probability stated in Regulatory Guide 1.117, then specific design provisions must be provided to reduce the estimate of damage probability to an allowable level. 5. For new applications, the statistical significance of an identified missile due to the design basis natural phenomena can be evaluated utilizing a probability analysis. Once a potential missile is identified, its statistical significance is determined by calculating the probability of missile occurrence. If this probability is less than 10 per year, the missile -7 is not considered significant. If the probability of occurrence is greater than 10 per -7 year, then the probability that it will impact a significant target is determined. If the product of these two probabilities is less than 10 per year, the missile is not considered -7 significant. If the above product is greater than 10 per year, the probability of -7 significant damage is determined. If the combined probability (product of all three) is less than 10 per year, the missile is not considered significant. If the combined -7 probability is greater than 10 per year missile protection of SSC important to safety -7 should be provided.24 64. All plants are required to be designed to protect safety-related equipment against damage 25 from missiles which might be generated by the design basis tornado for that plant. The reviewer verifies that the applicant has postulated missiles that include at least three objects: a massive high kinetic energy missile which deforms on impact, a rigid missile to test penetration resistance, and a small rigid missile of a