Document: NUREG-0800
Document ID: 91ccd6ba-6094-458e-842b-ff5e6b11f635
Document Type: srp
Title: INTERNALLY GENERATED MISSILES (OUTSIDE CONTAINMENT)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070370.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.1
CFR Part: 
CFR Title: 

Content:
missiles and to determine the SSC that require protection in order to maintain their safety-related functions. The reviewer may use failure mode and effect analyses and the results of reviews by other branches in evaluating specific SSC and the origin of possible missiles, in identifying the SSC that require protection from internally generated missiles and the adequacy of the protection provided. The protection provided is reviewed and is adequate if the SSC important to safety are afforded protection that meets the guidance of Regulatory Guide 1.115 position C.3. In addition, the Ccomponents within one train of a 25 system containing redundant trains need not be protected from missiles originating from the same train. 26 For new applications, the statistical significance of an identified missile 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 is not considered significant. If the probability of occurrence is greater -7 than 10 per year, the probability that it will impact a significant target is determined. If the -7 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 significant -7 damage is determined. If the combined probability (product of all three) is less than 10 per -7 year, the missile is not considered significant. If the combined probability is greater than 10-7 per year, missile protection of SSC important to safety should be provided by one or more of the methods listed above.27 The reviewer determines that non- safety-related SSC are protected from internally generated 28 missiles if their failure by a missile impact could prevent a required safety function of the SSC. The reviewer determines that procedures, analysis and design