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Federal Register / Vol. 86, No. 174 / Monday, September 13, 2021 / Notices which restricts with limited exceptions assistance for the central government unless the Secretary makes certain certifications regarding actions taken by the Government of Sri Lanka and reports to the Committees on Appropriations.
Countries identified above as candidate countries, as well as countries that would be considered candidate countries but for the applicability of legal provisions that prohibit U.S.
economic assistance, may be the subject of future statutory restrictions or determinations, or changed country circumstances, that affect their legal eligibility for assistance under part I of the Foreign Assistance Act by reason of application of the Foreign Assistance Act or any other provision of law for FY
2022.
FR Doc. 202119694 Filed 91021; 8:45 am BILLING CODE 921103P

NUCLEAR REGULATORY
COMMISSION
NRC20200237

Considerations for Estimating SiteSpecific Probable Maximum Precipitation at Nuclear Power Plants in the United States of America Nuclear Regulatory Commission.
ACTION: NUREG; issuance.
AGENCY:

The U.S. Nuclear Regulatory Commission NRC is issuing a knowledge management NUREG, NUREG/KM0015, Considerations for Estimating Site-Specific Probable Maximum Precipitation at Nuclear Power Plants in the United States of America. The NRC staff and Oak Ridge National Laboratory have prepared a reference document summarizing recent lessons-learned in connection with a review of the site-specific probable maximum precipitation SSPMP
estimates used by some nuclear power plant owners and operators in connection with a recent re-evaluation of external flooding at their respective project sites.
DATES: NUREG/KM0015 is available on September 13, 2021.
ADDRESSES: Please refer to Docket ID
NRC20200237 when contacting the NRC about the availability of information regarding this document.
You may obtain publicly available information related to this document using any of the following methods:
Federal Rulemaking Website: Go to https www.regulations.gov and search for Docket ID NRC20200237. Address
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questions about Docket IDs in Regulations.gov to Stacy Schumann;
telephone: 3014150624; email:
Stacy.Schumann@nrc.gov. For technical questions, contact the individual listed in the FOR FURTHER INFORMATION
CONTACT section of this document.
NRCs Agencywide Documents Access and Management System ADAMS: You may obtain publicly available documents online in the ADAMS Public Documents collection at https www.nrc.gov/reading-rm/
adams.html. To begin the search, select Begin Web-based ADAMS Search. For problems with ADAMS, please contact the NRCs Public Document Room PDR
reference staff at 18003974209, 301
4154737, or by email to pdr.resource@
nrc.gov. NUREG/KM0015, Considerations for Estimating SiteSpecific Probable Maximum Precipitation at Nuclear Power Plants in the United States of America is available in ADAMS under Accession No. ML21245A418.
Attention: The PDR, where you may examine, and order copies of public documents, is currently closed. You may submit your request to the PDR via email at pdr.resource@nrc.gov or call 18003974209 or 3014154737, between 8:00 a.m. and 4:00 p.m. ET, Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT:
Kevin Quinlan, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 205550001; telephone: 301415
6809, email: Kevin.Quinlan@nrc.gov.
SUPPLEMENTARY INFORMATION:
I. Background By letter dated March 12, 2012, the NRC issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status licensees to reevaluate seismic and external flooding for their sites against current Commission requirements and guidance. This request was made consistent with paragraph 50.54f of title of the Code of Federal Regulations 10 CFR, Conditions of licenses. The request was issued in connection with implementing lessons-learned identified by the staff, and described in their NearTerm Task Force Report, following the 2011 accident at the Fukushima Dai-ichi nuclear power plant. In connection with this request, owners and operators were to re-evaluate flood hazards at their respective sites using present-day methods and regulatory guidance used by the NRC staff when reviewing 10
CFR part 52 applications for Early Site
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Permits and Combined Operating Licenses.
In response to the staffs 2012
50.54f information request, owners and licensees submitted about 60
external flood hazard re-evaluation reports FHRRs corresponding to the operating fleet of power reactors. In the matter of the probable maximum precipitation PMP value used for some of the flood-hazard re-evaluations primarily the estimation of local intense precipitation and riverine-based floods, current NRC guidance documents recommend the use of the PMP estimation methods described in a series of Hydrometeorological Reports HMRs developed by the National Oceanographic and Atmospheric Administration NOAA. The PMP event itself is generally defined as the greatest depth of precipitation for a given duration meteorologically possible for a design watershed or a given storm area at a particular time of year. The estimated PMP over a particular watershed or basin results in a flood magnitude for which there is virtually no risk of exceeding. The challenge, however, is that HMR-derived PMP
estimates are based on methodologies and data which have not been updated with rainfall and storm events which have occurred in the decades since the HMRs were last published.
Upon review of the FHRRs, the staff found that about 26 project sites responding to the 50.54f information request submitted PMP estimates that were not based on NOAA HMRs but were developed by a commercial interest. As part of the FHRR process, the staff conducted an audit of the commercial vendor who developed the site-specific PMP estimates to betterunderstand the technical basis underlying the approach. In all cases, these SSPMP estimates were less than those obtained from the applicable HMR. Although the development and estimation of the SSPMP studies reviewed by the staff generally followed processes similar to those described in the existing guidance, several different methods, data sources, assumptions, and procedures were used to obtain site specific results other than those found using the HMR methodology.
Based on the staffs 50.54f review experience and in anticipation of its continued use, this NUREG summarizes the lessons-learned concerning the review and application of a SSPMP. To that end, this NUREG addresses the following topics:
Storm Selection Storm Reconstruction Storm Transposition
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