Process for the Ongoing Assessment of Natural Hazard Information (POANHI)

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POANHI Background

Subsequent to the events at Fukushima Dai-ichi, the NRC implemented the process for the ongoing assessment of natural hazards information (POANHI) in accordance with the staff requirements memorandum (SRM), SRM-SECY-16-0144, “Proposed Resolution of Remaining Tier 2 and 3 Recommendations Resulting from the Fukushima Dai-ichi Accident,” dated May 3, 2017 (ADAMS Accession No. ML16039A175). This SRM approved the staff’s recommendations for the development of the process enhancements described in SECY-16-0144, dated December 29, 2016 (ADAMS Accession No. ML16286A586), for ongoing assessment of natural hazards information. NRR Office Instruction (OI) LIC-208, “Process for the Ongoing Assessment of Natural Hazard Information,” (ADAMS Accession No. ML19210C288) institutionalizes a defined structure and procedures to implement the POANHI framework.

The POANHI framework has the following three attributes:

  • Enhances safety,
  • Efficiently integrates with existing processes, and
  • Provides stability and predictability


The primary responsibility for executing the POANHI framework resides with the External Hazards Center of Expertise (EHCOE) in NRR. EHCOE is staffed by technical experts capable of assessing potential climatology-driven hazards (snow loads, tornado and hurricane wind loads, etc.), atmospheric dispersion of radionuclides, local intense precipitation and associated site drainage, all potential flood-related hazards (rivers, streams, dam failure, etc.), evaluation of the safety-related water supply, all potential coastal hazards (storm surge, tsunami, etc.), groundwater flow and radionuclide transport, potential for geologic hazards (e.g., faulting, karst, and subsidence), potential for ground shaking (i.e., seismology and geophysics), and stability of subsurface materials, foundations, and slopes (geotechnical engineering). The natural hazards considered under POANHI include:

POANHI Activities

There are three primary components to address new natural hazard information:

  • Knowledge base activities
  • Active technical engagement and coordination
  • Assessment activities

Process for the Ongoing Assessment of Natural Hazard Information

The figure above illustrates POANHI activities, beginning with the identification of new information followed by an assessment of potential safety impacts at the screening stage. At the screening stage, the NRC staff will assess the potential safety impact of the new information. This assessment may be considered generically across an entire class of licensed facilities or more specific to individual facilities, depending on the hazard and scope of information. Finally, the staff will decide to either take no further action or to pursue a regulatory action. If no action is needed, the NRC staff will document the results of the assessment and share applicable information publicly. If regulatory action is needed, the staff will identify the appropriate framework, such as initiation of additional research, referral to the generic issues program, or engagement with licensees to request additional site-specific information. Stakeholder interactions may occur at any step in the process and the level of stakeholder engagement will depend on the scope of the information being considered.

The NRC produces an annual report of POANHI activities. The reports are available in the Agencywide Documents Access and Management System (ADAMS) and through the links below.


The NRC considers several flood-causing mechanisms in its assessment of hydrologic hazards. These flood-causing mechanisms of interest include riverine based flood and upstream dam failure, local intense precipitation (LIP), tsunami, storm surge, seiche, ice dams and jams, channel migration, and groundwater. These mechanisms are consistent with the natural hazards described in Chapter 2.4 of NUREG-0800, the Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition.


Within the field of meteorology, the NRC considers regional climatology and local meteorology, onsite meteorological monitoring and atmospheric dispersion estimates as described in Chapter 2.3 of NUREG-0800.

Geology and Seismology

Within the fields of geology and seismology, the NRC considers regional and local geologic and seismological hazards as well as onsite geologic and seismic hazards. The consideration of these hazards is described in more detail in Chapter 2.5 of NUREG-0800.

Frequently Asked Questions

What is POANHI?

POANHI is a framework for the NRC staff to systematically monitor and assess new and updated natural hazards information to determine the safety significance of the new information. The POANHI activities are led by a cross-agency team from the Office of Nuclear Reactor Regulation and the Office of Nuclear Regulatory Research. The POANHI framework integrates with existing regulatory activities (e.g., collects information from research and oversight activities as well as from operating experience), uses NRC’s risk-informed regulatory framework, supports coordination between relevant regulatory offices, and facilitates transfer of issues to the appropriate regulatory program. In addition, the proposed framework better integrates NRC processes with the broader natural hazards technical community.

Will the staff engage with external experts to collect new hazard information?

The NRC staff will leverage periodic interactions with internal and external organizations (e.g., Federal agencies, industry, and international counterparts) as well as academia and other technical and scientific organizations to facilitate identification of new data, models, and methods. These technical coordination activities and partnerships may include the following groups:

  • federal partner agencies (e.g., Department of Energy; United States Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), United States Army Corps of Engineers, Federal Energy Regulatory Commission, United States Bureau of Reclamation, Department of Homeland Security/Federal Emergency Management Agency, and the National Institute of Standards and Technology);
  • industry stakeholders (e.g., Nuclear Energy Institute, Electric Power Research Institute);
  • professional societies and consensus standards organizations (e.g., ANSI/American Nuclear Society; American Society of Civil Engineers; American Society of Heating, Refrigerating, and Air-Conditioning Engineers); and
  • international counterparts (e.g., Canadian Nuclear Safety Commission, Organisation for Economic Co-operation and Development/Nuclear Energy Agency, International Atomic Energy Agency).

How will the staff assess the potential significance of new hazard information?

The staff will aggregate the new information with previously collected information to assess the new information for potential significance in the context of accumulated hazard information, rather than in isolation. This assessment will evaluate the change in the hazard represented by the aggregated information and consider available risk insights to determine whether the change in the hazard has a potentially significant effect on plant safety. The assessment will be performed by NRC subject matter experts. Assessment activities are intended to require limited resources and use information contained within the knowledge base to perform a limited scope quantitative or qualitative initial screening to determine if the change in hazard is potentially significant.

Does POAHNI include man-made hazards?

No. The staff concluded that it is not necessary to include man-made hazards in the proposed framework because of fundamental differences in the types of changes that arise due to natural and man-made hazards. Specifically, changes related to natural hazards generally arise due to a gradual evolution in the fundamental state of knowledge regarding natural phenomena and available assessment tools. Conversely, changes in man-made hazards arise due to discrete, well-defined, and site-specific events (e.g., construction of a new facility or pipeline in the vicinity of a plant) and existing regulatory processes have been shown to be sufficient without the need for enhancements.

What action will staff take when the POANHI screening identifies a potentially significant new hazard?

If the staff finds that the new hazard information has a potentially significant effect on plant safety, it will refer the issue to the appropriate NRC regulatory program for detailed assessment and further action. Regulatory programs for these referrals include:

  • transfer of an issue to the relevant program office for resolution (e.g., via plant-specific assessment and regulatory action),
  • transfer of the issue to the Generic Issues Program, if the new information could potentially affect safety at multiple plants and the issue meets other Generic Issues Program screening criteria, or
  • identification of the need for further research if a better understanding of the new information could improve the staff’s understanding of the hazard and the resulting potential effects on plant safety.

Members of the public and external stakeholders can submit any comments or feedback to the staff by emailing