Hazards
HAZARD CATALOG
This page catalogs the external hazards considered in nuclear power plant design. Hazards are organized here by origin (natural or man‑made) with representative examples and typical plant impacts for each. Individual hazard pages provide detailed descriptions, analysis methods, and key references; links are provided where pages are available.
Hazard Catalog
Natural Hazards
| Hazard | Typical plant impacts |
|---|---|
| High winds (tornadoes, hurricanes, straight‑line winds) | Wind‑borne missiles can damage exposed SSCs such as piping, vent stacks, and tanks; transmission line and switchyard damage can cause LOOP; debris can clog cooling‑water intakes, leading to LUHS. |
| Extreme temperatures (heat waves, extreme cold) | Elevated water temperatures can reduce heat‑sink capacity; extreme cold can cause frazil‑ice buildup in intake structures and impair outdoor sensing equipment; either extreme can force reactor shutdown or power reduction. |
| External flooding (riverine, coastal, storm‑surge) | Inundation can breach flood barriers, causing various challenges; hydrostatic and buoyancy loads can damage structures; extended flooding can lead to prolonged outage. |
| Intense precipitation (short‑duration extreme rain) (a type of external flooding) |
Overland flow and flash flooding can inundate low‑lying equipment and impede personnel access; water ingress into electrical cabinets can cause short‑circuit failures and equipment damage. |
| Sea‑level rise (coastal sites) (a type of external flooding) |
Raises baseline water level, reducing freeboard and increasing the probability of flood‑barrier breach during storm events; amplifies wave energy reaching coastal structures. |
| Geological hazards (earthquake/seismic, landslide, volcanic activity) | Ground motion can damage structures, pipelines, and support systems; switchyard damage can cause LOOP; rupture of water‑intake lines can cause LUHS. |
| Wildfire | Direct flame and radiant heat can damage exterior equipment and fire‑protection systems; smoke and ash can foul air‑intake filters; fire damage to transmission corridors can cause LOOP. |
| Lightning | Transient overvoltages can damage switchgear, transformers, and instrumentation, causing LOOP; induced surges can impair control and protection circuits. |
| Geomagnetic Disturbances (GMD) | Geomagnetically induced currents (GIC) can saturate high‑voltage transformers, causing reactive power absorption and voltage instability; widespread grid disturbance can lead to LOOP. |
Man‑Made Hazards
| Hazard | Typical plant impacts |
|---|---|
| Aircraft impact | Direct kinetic impact can damage structures and containment; fuel‑fed fires can threaten safety‑related equipment and fire‑protection systems; severed power‑feed lines can cause various challenges. |
| Industrial accidents (offsite pipeline rupture, chemical release, explosion) |
Blast overpressure and explosion‑generated missiles can damage structures and SSCs; toxic or flammable releases may force plant shutdown and restrict site access. |
| Cyber‑physical threats | Disruption of safety‑related control logic can cause premature reactor trip, loss of offsite power, or impairment of cooling systems. |
Combined & Cascading Hazards — When two or more external events affect a plant simultaneously, sequentially, or through causal linkage. Representative hazard combinations and their typical plant impacts are cataloged on the combined and cascading hazards page.
EPRI technical point of contact: Chris Rochon (CRochon@epri.com)
Date last reviewed: 2026-05-21