Document: NRC Regulatory Guide
Document ID: 22ccfd5e-c5d8-4615-a02c-32369aa9f533
Document Type: regulatory_guide
Title: Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1930/ML19308B636.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.200
CFR Part: 
CFR Title: 

Content:
� Fire DG-1362, Appendix D, Page D-4 Hazard Group/ Hazard Direct or Secondary Impact of Hazard Note 1 Seismic activity and volcanic activity are hazards in the tectonic activity hazard group. However, historically, seismic activity has been evaluated as a hazard group (Part 5 of this standard). Although seismic events due to volcanic activity may be evaluated as part of the seismic hazard group, other potential impacts of volcanic activity may need to be analyzed separately. External Fire: Direct (e.g., thermal effects) and indirect effects (e.g., generation of combustion products, transport of firebrand) of a fire outside the plant boundary that causes functional failure of plant SSCs. Hazards that could potentially result in external fire include Wildfire, forest fire, grass fire The different causes of fire that can occur outside the site boundary. Extreme Temperature An occurrence of extreme heat or cold temperatures causing SSC functional failure. Hazards that could potentially result in extreme temperature include High Ambient Temperature Effects on SSCs operation due to abnormally high ambient temperatures resulting from weather phenomena. Secondary hazards resulting from high ambient temperatures, include, but are not necessarily limited to: • Low Lake or River Water Level Low Ambient Temperature Effects on SSC operation due to abnormally low ambient temperatures resulting from weather phenomena. Secondary hazards resulting from low ambient temperatures, include, but are not necessarily limited to: • Frost • Ice cover • Snow Ground Shifts Surface movement of the ground (not associated with tectonic activity) causing SSC functional failure. Hazards that could potentially result in ground shifts include Avalanche Rapid flow of a large mass of accumulated frozen precipitation and other debris down a sloped surface resulting in dynamic loading of SSCs at or in the plant analyzed area causing functional failure, or adverse impact on natural water supplies