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	<id>https://externalhazards.epri.com/index.php?action=history&amp;feed=atom&amp;title=Hazards</id>
	<title>Hazards - Revision history</title>
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	<updated>2026-07-02T01:35:34Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
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	<entry>
		<id>https://externalhazards.epri.com/index.php?title=Hazards&amp;diff=130&amp;oldid=prev</id>
		<title>Admin at 18:31, 18 June 2026</title>
		<link rel="alternate" type="text/html" href="https://externalhazards.epri.com/index.php?title=Hazards&amp;diff=130&amp;oldid=prev"/>
		<updated>2026-06-18T18:31:10Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 18:31, 18 June 2026&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l8&quot;&gt;Line 8:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 8:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;status: published&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;status: published&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;summary: Parent catalog page listing all external hazard classes with representative examples and plant impacts.&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;summary: Parent catalog page listing all external hazard classes with representative examples and plant impacts.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
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&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;span style=&amp;quot;background:#5B8DB8; color:#FFF; padding:3px 14px; border-radius:12px; font-size:80%; font-weight:bold; letter-spacing:1px;&amp;quot;&amp;gt;HAZARD CATALOG&amp;lt;/span&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;span style=&amp;quot;background:#5B8DB8; color:#FFF; padding:3px 14px; border-radius:12px; font-size:80%; font-weight:bold; letter-spacing:1px;&amp;quot;&amp;gt;HAZARD CATALOG&amp;lt;/span&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
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&lt;/table&gt;</summary>
		<author><name>Admin</name></author>
	</entry>
	<entry>
		<id>https://externalhazards.epri.com/index.php?title=Hazards&amp;diff=60&amp;oldid=prev</id>
		<title>Admin: 1 revision imported</title>
		<link rel="alternate" type="text/html" href="https://externalhazards.epri.com/index.php?title=Hazards&amp;diff=60&amp;oldid=prev"/>
		<updated>2026-06-09T22:29:35Z</updated>

		<summary type="html">&lt;p&gt;1 revision imported&lt;/p&gt;
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				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 22:29, 9 June 2026&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-notice&quot; lang=&quot;en&quot;&gt;&lt;div class=&quot;mw-diff-empty&quot;&gt;(No difference)&lt;/div&gt;
&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;</summary>
		<author><name>Admin</name></author>
	</entry>
	<entry>
		<id>https://externalhazards.epri.com/index.php?title=Hazards&amp;diff=59&amp;oldid=prev</id>
		<title>10.1.236.167 at 14:23, 2 June 2026</title>
		<link rel="alternate" type="text/html" href="https://externalhazards.epri.com/index.php?title=Hazards&amp;diff=59&amp;oldid=prev"/>
		<updated>2026-06-02T14:23:36Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;&amp;lt;!-- PAGE METADATA&lt;br /&gt;
page_type: landing_page&lt;br /&gt;
page_id: HAZARD_CATALOG&lt;br /&gt;
canonical_hazard_id: N/A&lt;br /&gt;
related_hazard_ids: EH-HYD, EH-ATM, EH-GEO, EH-BIO, EH-ANT, EH-ELE, EH-CMB&lt;br /&gt;
authoritative: true&lt;br /&gt;
revision_date: 2026-03-12&lt;br /&gt;
status: published&lt;br /&gt;
summary: Parent catalog page listing all external hazard classes with representative examples and plant impacts.&lt;br /&gt;
--&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;div style=&amp;quot;border-left: 4px solid #5B8DB8; padding-left: 16px;&amp;quot;&amp;gt;&lt;br /&gt;
&amp;lt;span style=&amp;quot;background:#5B8DB8; color:#FFF; padding:3px 14px; border-radius:12px; font-size:80%; font-weight:bold; letter-spacing:1px;&amp;quot;&amp;gt;HAZARD CATALOG&amp;lt;/span&amp;gt;&lt;br /&gt;
&lt;br /&gt;
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.&lt;br /&gt;
&lt;br /&gt;
== Hazard Catalog ==&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Natural Hazards&amp;#039;&amp;#039;&amp;#039;  &lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
! Hazard !! Typical plant impacts&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;[[Hazards/High Winds|High winds (tornadoes, hurricanes, straight‑line winds)]]&amp;#039;&amp;#039;&amp;#039; || 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.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;[[Hazards/Extreme Temperature|Extreme temperatures (heat waves, extreme cold)]]&amp;#039;&amp;#039;&amp;#039; || 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.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;[[Hazards/External Flooding|External flooding (riverine, coastal, storm‑surge)]]&amp;#039;&amp;#039;&amp;#039; || Inundation can breach flood barriers, causing various challenges; hydrostatic and buoyancy loads can damage structures; extended flooding can lead to prolonged outage.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Intense precipitation (short‑duration extreme rain)&amp;#039;&amp;#039;&amp;#039;&amp;lt;br&amp;gt;&amp;lt;small&amp;gt;&amp;#039;&amp;#039;(a type of external flooding)&amp;#039;&amp;#039;&amp;lt;/small&amp;gt; || 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.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;[[Hazards/External Flooding|Sea‑level rise (coastal sites)]]&amp;#039;&amp;#039;&amp;#039;&amp;lt;br&amp;gt;&amp;lt;small&amp;gt;&amp;#039;&amp;#039;(a type of external flooding)&amp;#039;&amp;#039;&amp;lt;/small&amp;gt; || Raises baseline water level, reducing freeboard and increasing the probability of flood‑barrier breach during storm events; amplifies wave energy reaching coastal structures.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Geological hazards ([[Hazards/Seismic|earthquake/seismic]], landslide, volcanic activity)&amp;#039;&amp;#039;&amp;#039; || Ground motion can damage structures, pipelines, and support systems; switchyard damage can cause LOOP; rupture of water‑intake lines can cause LUHS.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;[[Hazards/Wildfire|Wildfire]]&amp;#039;&amp;#039;&amp;#039; || 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.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;[[Hazards/Lightning|Lightning]]&amp;#039;&amp;#039;&amp;#039; || Transient overvoltages can damage switchgear, transformers, and instrumentation, causing LOOP; induced surges can impair control and protection circuits.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;[[Hazards/Geomagnetic Disturbance|Geomagnetic Disturbances (GMD)]]&amp;#039;&amp;#039;&amp;#039; || Geomagnetically induced currents (GIC) can saturate high‑voltage transformers, causing reactive power absorption and voltage instability; widespread grid disturbance can lead to LOOP.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Man‑Made Hazards&amp;#039;&amp;#039;&amp;#039;  &lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
! Hazard !! Typical plant impacts&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Aircraft impact&amp;#039;&amp;#039;&amp;#039; || 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.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Industrial accidents&amp;#039;&amp;#039;&amp;#039;&amp;lt;br&amp;gt;(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.&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Cyber‑physical threats&amp;#039;&amp;#039;&amp;#039; || Disruption of safety‑related control logic can cause premature reactor trip, loss of offsite power, or impairment of cooling systems.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;[[Hazards/Compound and Cascading Hazards|Combined &amp;amp; Cascading Hazards]]&amp;#039;&amp;#039;&amp;#039; — 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 [[Hazards/Compound and Cascading Hazards|combined and cascading hazards]] page.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/div&amp;gt;&lt;br /&gt;
&lt;br /&gt;
----&lt;br /&gt;
&amp;#039;&amp;#039;EPRI technical point of contact: Chris Rochon ([mailto:CRochon@epri.com CRochon@epri.com])&amp;#039;&amp;#039;&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;Date last reviewed: 2026-05-21&amp;#039;&amp;#039;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;!-- V1.0 PLACEHOLDERS — Reviewed summary text for placeholder export.&lt;br /&gt;
Do not modify without updating the corresponding subpage content.&lt;br /&gt;
&lt;br /&gt;
@@PLACEHOLDER: Hazards/High_Winds&lt;br /&gt;
High-wind external hazards (tornadoes, hurricanes, straight-line winds, and severe thunderstorms) can subject nuclear plant structures to extreme lateral pressures, launch debris at high velocities, and create rapid atmospheric-pressure differentials. These forces interact with several levels of defense, from the containment shell and auxiliary buildings down to switchyard components and offsite transmission infrastructure. Because high-wind events span a wide spectrum of intensities, durations, and geographic reach, their assessment requires hazard-specific climatological data, detailed structural fragility modeling, and close integration with the probabilistic risk framework.&lt;br /&gt;
@@END&lt;br /&gt;
&lt;br /&gt;
@@PLACEHOLDER: Hazards/External_Flooding&lt;br /&gt;
External flooding encompasses all water-related natural or human-influenced hazards that can inundate a nuclear power plant site or degrade plant structures, systems, and components. Flood mechanisms range from riverine flooding and local intense precipitation to coastal storm surge, tsunami, dam or levee failure, ice-induced flooding, sea level rise, groundwater ingress, and wind-driven rain intrusion. The severity of a flood event depends on the rate of rise, peak water level, duration, flow velocity, debris loading, and whether concurrent hazards accompany the flood.&lt;br /&gt;
@@END&lt;br /&gt;
&lt;br /&gt;
@@PLACEHOLDER: Hazards/Wildfire&lt;br /&gt;
Wildfire refers to uncontrolled fires that spread through vegetative fuels such as forests, grasslands, and brush. When wildfires occur near nuclear power plant sites, they can threaten electrical grid infrastructure, degrade air quality, restrict site access, and in extreme cases pose direct thermal hazards to site structures. Electrical disruptions are the most commonly observed wildfire impact on nuclear power plants, with wildfires capable of physically damaging transmission infrastructure or triggering protective de-energization of lines. EPRI [https://www.epri.com/research/products/000000003002032022 3002032022] provides a four-step Wildfire Vulnerability Assessment (WVA) framework and includes a review of 23 wildfire events affecting nuclear plants globally (1990–2025).&lt;br /&gt;
@@END&lt;br /&gt;
&lt;br /&gt;
@@PLACEHOLDER: Hazards/Extreme_Temperature&lt;br /&gt;
Extreme temperature events encompass both extreme heat and extreme cold conditions that can challenge nuclear power plants. Extreme heat can degrade the performance of cooling systems, HVAC equipment, and heat exchangers by reducing thermal margins and raising ultimate heat sink temperatures. Extreme cold can cause freezing of instrument lines, intake icing (including frazil ice formation), and impairment of water supply systems.&lt;br /&gt;
@@END&lt;br /&gt;
&lt;br /&gt;
@@PLACEHOLDER: Hazards/Lightning&lt;br /&gt;
Lightning is a natural atmospheric electrical discharge that can produce direct physical damage, high transient voltages, electromagnetic interference, and ground potential rise at nuclear power plant sites. Lightning strikes can affect plant electrical systems, instrumentation and control equipment, grounding infrastructure, and offsite power connections, potentially initiating reactor trips and challenging important systems. Lightning activity has been observed to increase in some historically low-risk zones, and digital equipment may be more susceptible to lightning-induced transient voltages than older analog counterparts.&lt;br /&gt;
@@END&lt;br /&gt;
&lt;br /&gt;
@@PLACEHOLDER: Hazards/Geomagnetic_Disturbance&lt;br /&gt;
Geomagnetic disturbances are variations in the Earth&amp;#039;s magnetic field caused by solar activity, primarily coronal mass ejections. These disturbances induce electric fields at the Earth&amp;#039;s surface that drive quasi-dc geomagnetically induced currents through grounded conductors, including transmission lines and transformer neutrals. GIC-driven transformer saturation can cause widespread reactive power absorption, voltage instability, and cascading grid disturbances that threaten offsite power availability to nuclear plants.&lt;br /&gt;
@@END&lt;br /&gt;
&lt;br /&gt;
@@PLACEHOLDER: Hazards/Compound_and_Cascading_Hazards&lt;br /&gt;
Compound and cascading hazards arise when two or more external events affect a nuclear power plant simultaneously, sequentially, or through causal linkage. Industry practice distinguishes three categories: consequential hazards (one event triggers another), correlated hazards (a common cause produces simultaneous effects), and coincidental hazards (unrelated events overlap in time). Combined events can simultaneously challenge multiple plant functions, producing consequences qualitatively different from and more severe than any single event. The 2011 Fukushima Daiichi accident demonstrated the catastrophic potential of cascading hazards.&lt;br /&gt;
@@END&lt;br /&gt;
--&amp;gt;&lt;/div&gt;</summary>
		<author><name>10.1.236.167</name></author>
	</entry>
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