Document: NUREG-0800
Document ID: 1dabf375-d973-4499-a224-cf6b3b2a0de9
Document Type: srp
Title: INTERNALLY GENERATED MISSILES (OUTSIDE CONTAINMENT)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070370569.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.1
CFR Part: 
CFR Title: 

Content:
statistical significance is determined by calculating the probability of missile occurrence. If this probability is less than 10-7 per year, the missile is not considered statistically significant. If the probability of occurrence is greater than 10-7 per year, the probability of impact on a significant target is determined. If the product of these two probabilities is less than 10-7 per year, the missile is not considered statistically significant. If the product is greater than 10-7 per year, the probability of significant damage is determined. If the combined probability (product of all three) is less than 10-7 per year, the missile is not considered statistically significant. If the combined probability is greater than 10-7 per year, missile protection of SSCs important to safety, and of nonsafety-related SSCs whose failure could affect an intended safety function of the safety related SSCs, should be provided by one or more of the six methods listed below. 2. Missile protection for SSCs important to safety is adequate if provided by one or more of the following methods: (1) locating the system or component in a missile-proof structure, (2) separating redundant systems or components for the missile path or range, (3) providing local shields and barriers for systems and components, (4) designing the equipment to withstand the impact of the most damaging missile, (5) providing design features to prevent the generation of missiles, or (6) orienting missile sources to prevent missiles from striking equipment important in safety. RG 1.117 provides guidance on the SSCs that should be protected. Where barriers are used as a method of protection of SSCs from internal missiles, the design of the barriers is acceptable if it meets the guidance of RG 1.115 position C.3. Components within one train of a system with redundant trains need not be protected from missiles originating from the same train. Technical Rationale The technical rationale for application of these