Document: NRC Regulatory Guide
Document ID: 8a2332d3-66ca-40af-84e1-507db8b26559
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:
normally high ambient temperatures resulting from weather phenomena or other causes. Secondary hazards resulting from high ambient temperatures include, but are not necessarily limited to, low lake or river water levels. Ice Reduced flow or blockage of water systems due to the accumulation of ice on or in (i.e., frazil ice) a body of water (e.g., lakes, rivers, ocean) or the water system itself. This hazard is also analyzed for the effects of static loading of SSCs due to ice accumulation. Low Winter Temperature Effects on SSC operation due to abnormally low ambient temperatures resulting from weather phenomena or other causes. Secondary hazards resulting from low ambient temperatures include, but are not necessarily limited to, frost, ice, and snow. RG 1.247, Appendix B, Page B-4 Hazard Hazard Group Direct or Secondary Impact of Hazard Ground Shifts Coastal Erosion Natural removal of earth from a shoreline of a body of water (e.g., river, lake, ocean) due to surface processes (e.g., wave action, tidal currents, wave currents, drainage, or winds and including river bed scouring) that may impact the structural integrity of SSCs. Landslide Rapid flow of a large mass of earth or other debris (e.g., mud) down a sloped surface resulting in dynamic loading of SSCs at or in the plant’s analyzed area causing functional failure or adverse impact on natural water supplies used for heat rejection. Sinkholes Ground movement effects on SSC structural integrity due to karst (i.e., topography formed by the dissolution of soluble rocks). Soil Shrink-Swell Dynamic forces on structures’ foundations due to the expansion (swelling) and contraction (shrinking) of soil resulting from changes in the soil moisture content. Heat Sink Effects Drought A shortage of surface water supplies due to a period of below-average precipitation in a given region, thereby depleting the water supply needed for the various water-cooling functions at the facility. Low Lake or River Water Level A