Document: NRC Regulatory Guide
Document ID: cde52d5a-adf9-49be-9d1f-59449dfca895
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
G 1.247, Appendix B, Page B-6 Hazard Hazard Group Direct or Secondary Impact of Hazard Snow Cover The accumulation of snow could result in transportation accidents or directly cause dynamic loading or freezing conditions as a result of snow cover. Site-Generated Missiles Turbine-Generated Missiles Damage to SSCs from a missile generated internal or external to the plant PRA boundary from rotating turbines. Damage may result from a falling missile or a missile ejected directly toward SSCs (i.e., low-trajectory missiles). Missiles Generated from Other Sources Damage to SSCs due to a missile generated from sources other than a turbine, such as high- pressure gas cylinders. Transportation Accidents Aircraft Impact An aircraft (either a portion of or the entire aircraft) that collides either directly or indirectly (i.e., skidding impact) with one or more SSCs at or in the plant’s analyzed area causing functional failure. Secondary hazards resulting from an aircraft impact include, but are not necessarily limited to, fire. Fog Low-lying water vapor in the form of a cloud or obscuring haze of atmospheric dust or smoke resulting in impeded visibility that could result in, for example, a transportation accident. Frost A thin layer of ice crystals that forms on the ground or on the surface of an earth-bound object when the temperature of the ground or surface of the object falls below freezing. This hazard could result in a transportation accident. Railcar Impact Effects of an onsite railcar impact with one or more SSCs. Ship Impacts Effects of a waterborne vessel impact with a water intake or outlet SSC. Vehicle Impacts Effects of an onsite vehicle impact with one or more SSCs. Transportation Vehicle Explosion Offsite accidents involving transportation resulting in a release of hazardous materials or combustion products, an explosion, or the generation of missiles causing functional failure of SSCs or preventing operator actions. Hazards that could potentially result in