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	This wiki provides a structured and accessible overview of external hazards as they pertain to the risk assessment, hazard characterization, and operational resilience of nuclear power plants (NPPs). External hazards such as high winds, flooding, wildfires, extreme precipitation, and extreme heat events can potentially pose significant risks to NPPs. Understanding and mitigating these risks is essential for ensuring operational continuity, regulatory compliance, and public safety.		This wiki provides a structured and accessible overview of external hazards as they pertain to the risk assessment, hazard characterization, and operational resilience of nuclear power plants (NPPs). External hazards such as high winds, flooding, wildfires, extreme precipitation, and extreme heat events can potentially pose significant risks to NPPs. Understanding and mitigating these risks is essential for ensuring operational continuity, regulatory compliance, and public safety.

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Site Map

New page

__NOTOC__
This wiki provides a structured and accessible overview of external hazards as they pertain to the risk assessment, hazard characterization, and operational resilience of nuclear power plants (NPPs). External hazards such as high winds, flooding, wildfires, extreme precipitation, and extreme heat events can potentially pose significant risks to NPPs. Understanding and mitigating these risks is essential for ensuring operational continuity, regulatory compliance, and public safety.

This wiki is designed for engineers, analysts, and technical professionals who are either new to the domain or seeking to apply industry guidance and methodologies in their work. It serves as both an educational resource and a practical reference, mapping out the landscape of external hazard assessment in the nuclear sector.

=How External Hazards Are Managed=
The nuclear industry addresses external hazards through a process that begins with identifying site-specific hazards and proceeds through hazard characterization, exposure assessment, and vulnerability assessment. Deterministic evaluation forms the foundation of this process, confirming that safety-related structures, systems, and components can withstand design basis hazard levels with adequate margins. Where additional insights are needed, probabilistic risk assessment and related analyses complement the deterministic evaluation by assessing risk across a broader range of scenarios. Mitigation, adaptation, and periodic reassessment can feed updated information back into the process, ensuring that the evaluations remain current as new data, methods, and operating experience become available.

[[File:hazard_management_lifecycle.png|center|950px|link=|External Hazard Management Lifecycle]]

The major sections of this wiki map directly to stages in this process. The [[Foundations]] and [[Hazards|Catalog of Hazards]] pages address hazard identification and characterization. [[Methods and Tools]] covers the analytical approaches used for exposure assessment, vulnerability assessment, deterministic evaluation, and risk quantification. [[Industry Experience]] draws on operating experience to inform mitigation strategies.

=Start Here=
Choose a path based on what you need:

<div class="container" id="wikidiv">

<div class="fixed">
<div style="text-align:center;">[[Image:compass.png|x60px|link=Foundations]]</div>
<p class="wikilabel">
'''I'm New to External Hazards'''</p>
*'''[[Foundations]]''' — What external hazards are and why they matter
*'''[[How External Hazards Are Addressed in Nuclear Plants|How External Hazards Are Addressed]]''' — The big picture
*'''[[Terms and Definitions]]''' — Key terminology
*'''[[Historical Context and Evolution|Historical Context]]''' — How the field evolved
<div style="height:1.2em;"></div>
<p class="readmore" style="margin-top:8px;">
[[Foundations|Start with Foundations]]
</p>
</div>

<div class="fixed">
<div style="text-align:center;">[[Image:weather.png|x60px|link=Hazards]]</div>
<p class="wikilabel">
'''I Need Information on a Specific Hazard'''</p>
*Overview pages for each hazard type
*Mechanisms, effects, and assessment approaches
*Hazard-specific references and guidance
<div style="height:1.2em;"></div>
<p class="readmore">
[[Hazards|Browse the Catalog of Hazards]]
</p>
</div>

<div class="fixed">
<div style="text-align:center;">[[Image:info.png|x60px|link=Frequently Asked Questions]]</div>
<p class="wikilabel">
'''I Have a Quick Question'''</p>
*Common questions about external hazards
*Clarifications on terminology and scope
<div style="height:1.2em;"></div>
<p class="readmore">
[[Frequently Asked Questions|View the FAQ]]
</p>
</div>

</div>

=Site Map=
The map below shows all pages in this wiki. '''Bold''' links are active pages with full content; ''italic'' links are under development and currently contain summary placeholders.

* '''[[Foundations]]'''
** '''[[How External Hazards Are Addressed in Nuclear Plants]]'''
** '''[[Terms and Definitions]]'''
** '''[[Historical Context and Evolution]]'''
* '''[[Hazards|Catalog of Hazards]]'''
** '''[[Hazards/High Winds|High Winds]]'''
** '''[[Hazards/External Flooding|External Flooding]]'''
** ''[[Hazards/Seismic|Seismic]]''
** ''[[Hazards/Wildfire|Wildfire]]''
** ''[[Hazards/Extreme Temperature|Extreme Temperature]]''
** ''[[Hazards/Lightning|Lightning]]''
** ''[[Hazards/Geomagnetic Disturbance|Geomagnetic Disturbance]]''
** ''[[Hazards/Compound and Cascading Hazards|Compound and Cascading Hazards]]''
* '''[[Methods and Tools]]'''
<div class="mw-collapsible mw-collapsed" style="border:1px solid #ccc; padding:4px 12px; margin:4px 0 8px 18px; background:#f9f9f9; border-radius:4px;">
<div style="font-weight:bold; font-size:90%;">''Sub-pages (under development — click to expand)''</div>
<div class="mw-collapsible-content">
** '''[[Methods/Screening and Prioritization|Screening and Prioritization]]'''
** ''[[Methods/Deterministic Approaches|Deterministic Approaches]]''
** ''[[Methods/Beyond Design Basis|Beyond Design Basis]]''
** ''[[Methods/Probabilistic Risk Assessment|Probabilistic Risk Assessment]]''
** ''[[Methods/Walkdowns and Field Verification|Walkdowns and Field Verification]]''
** ''[[Methods/Tornado Missile Risk Evaluator|Tornado Missile Risk Evaluator (TMRE)]]''
** ''[[Methods/Tornado Missile Strike Calculator|Tornado Missile Strike Calculator (TMSC)]]''
** ''[[Methods/PFHA Tools|Probabilistic Flood Hazard Assessment (PFHA) Tools]]''
** ''[[Methods/Joint Probability Method|Joint Probability Method (JPM)]]''
** ''[[Methods/Climate Vulnerability Assessment|Climate Vulnerability Assessment (CVA)]]''
** ''[[Methods/CHIP Climate Projections|CHIP Climate Projections]]''
</div>
</div>
* '''[[Industry Experience]]'''
<div class="mw-collapsible mw-collapsed" style="border:1px solid #ccc; padding:4px 12px; margin:4px 0 8px 18px; background:#f9f9f9; border-radius:4px;">
<div style="font-weight:bold; font-size:90%;">''Sub-pages (under development — click to expand)''</div>
<div class="mw-collapsible-content">
** ''[[Industry Experience/High Winds|High Winds — Industry Experience]]''
** ''[[Industry Experience/External Flooding|External Flooding — Industry Experience]]''
** ''[[Industry Experience/Seismic|Seismic — Industry Experience]]''
** ''[[Industry Experience/Wildfire|Wildfire — Industry Experience]]''
** ''[[Industry Experience/Extreme Temperature|Extreme Temperature — Industry Experience]]''
** ''[[Industry Experience/Compound and Cascading Hazards|Compound and Cascading Hazards — Industry Experience]]''
</div>
</div>
* '''[[Frequently Asked Questions]]'''

;Related Resources
* [https://pra-info.epri.com/index.php?title=PRA_Information PRA Info landing page] ''(parent program)''

=Intended Audience=
This wiki is tailored for professionals working in nuclear safety, risk management, and plant operations:
*New engineers and analysts seeking to gain an overall understanding of external hazards.
*Experienced engineers and analysts seeking:
**Industry references, or
**Context for a specific type of assessment

----
''EPRI technical point of contact: Chris Rochon ([mailto:CRochon@epri.com CRochon@epri.com])''

''Date last reviewed: 2026-06-02''

External Hazards Home Page - Revision history

Admin at 18:30, 18 June 2026

Admin: 1 revision imported

10.1.237.113: /* Site Map */