Considerations for Estimating Site-Specific Probable Maximum Precipitation at Nuclear Power Plants in the United States of America, 50913-50914 [2021-19636]

Download as PDF 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. 2021–19694 Filed 9–10–21; 8:45 am] BILLING CODE 9211–03–P NUCLEAR REGULATORY COMMISSION [NRC–2020–0237] 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/KM–0015, ‘‘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/KM–0015 is available on September 13, 2021. ADDRESSES: Please refer to Docket ID NRC–2020–0237 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 NRC–2020–0237. Address lotter on DSK11XQN23PROD with NOTICES1 SUMMARY: VerDate Sep<11>2014 17:39 Sep 10, 2021 Jkt 253001 questions about Docket IDs in Regulations.gov to Stacy Schumann; telephone: 301–415–0624; email: Stacy.Schumann@nrc.gov. For technical questions, contact the individual listed in the FOR FURTHER INFORMATION CONTACT section of this document. • NRC’s 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 NRC’s Public Document Room (PDR) reference staff at 1–800–397–4209, 301– 415–4737, or by email to pdr.resource@ nrc.gov. NUREG/KM–0015, ‘‘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 1–800–397–4209 or 301–415–4737, 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 20555–0001; telephone: 301–415– 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 50.54(f) 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 PO 00000 Frm 00043 Fmt 4703 Sfmt 4703 50913 Permits and Combined Operating Licenses. In response to the staff’s 2012 § 50.54(f) 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 § 50.54(f) 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 staff’s § 50.54(f) 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 E:\FR\FM\13SEN1.SGM 13SEN1 50914 Federal Register / Vol. 86, No. 174 / Monday, September 13, 2021 / Notices lotter on DSK11XQN23PROD with NOTICES1 • Storm Representative Dew Point Selection • Precipitable Water Estimation • Dew Point Climatology, Moisture Maximization, and Moisture Transposition • Terrain Adjustment • Envelopment and Probable Maximum Precipitation Determination • Spatial and Temporal Distributions for SSPMP Applications This reference document describes the technical theory, data sources, and analysis methodology that could be used to derive a SSPMP estimate. Certain new terms are also introduced and defined. This reference document also identifies key technical (meteorological) considerations when reviewing a SSPMP estimate. To date, there is no clear NRC guidance on this topic or a commonly agreed-to approach on the estimation of SSPMP. As the staff may be reviewing additional SSPMP estimates in the future in connection with its regulatory responsibilities, it was decided to elicit stakeholder views on the matters and approaches discussed in this draft document. This document contains no regulatory guidance or regulatory positions. A request for comments on draft NUREG/KM–0015, (ADAMS Accession No. ML20356A293) was published in the Federal Register on December 29, 2020 (85 FR 85683), with a 60-day comment period ending on March 1, 2021. Comments received on NUREG/ KM–0015 can be found on the Federal Rulemaking website (https:// www.regulations.gov) under Docket ID NRC–2020–0237. II. Knowledge Management Since its inception, the Atomic Energy Commission and its successor, the NRC, have focused on preserving the (explicit) documentary record of its decision-making in the form of NUREGs, SECY Papers, Regulatory Guides, and other documents. However, in 2006, the agency recognized that there was a need to engage in a moreformal program of knowledge management that also reflects the lesstangible (implicit) human capital aspect of the agencies’ knowledge base. This feature was particularly important as the agency enters its fifth decade of operation—a period characterized by an increasing number of retirements among long-serving staff involved in many of the agencies’ early regulatory programs and associated licensing actions. Staff efforts thus far in preserving this legacy of experience that describe important historical events, facts, and research that were instrumental in shaping NRC’s VerDate Sep<11>2014 17:39 Sep 10, 2021 Jkt 253001 regulatory programs, can be found at https://www.nrc.gov/reading-rm/doccollections/nuregs/knowledge/. The purpose of this knowledge management NUREG (or NUREG/KM) is intended to satisfy an NRC goal of maintaining and preserving knowledge concerning the lessons-learned from the recent flood hazard re-evaluations at current and planned nuclear power plant sites performed most recently in connection with the staff 2012 § 50.54(f) reviews. Dated: September 8, 2021. For the Nuclear Regulatory Commission. Luissette Candelario-Quintana, Project Manager, External Hazards Branch, Division of Engineering and External Hazards, Office of Nuclear Reactor Regulation. [FR Doc. 2021–19636 Filed 9–10–21; 8:45 am] BILLING CODE 7590–01–P NUCLEAR REGULATORY COMMISSION [NRC–2021–0038] Safety-Related Steel Structures and Steel-Plate Composite Walls for Other Than Reactor Vessels and Containments Nuclear Regulatory Commission. ACTION: Regulatory guide; issuance; correction. AGENCY: The U.S. Nuclear Regulatory Commission (NRC) is correcting a notice that was published in the Federal Register (FR) on September 7, 2021, regarding the issuance of Regulatory Guide (RG) 1.243, ‘‘Safety-Related Steel Structures and Steel-Plate Composite Walls for other than Reactor Vessels and Containments.’’ This action is necessary to correct the NRC Docket ID in the notice title and the ADDRESSES section and to correct a date in the Additional Information section. DATES: The correction takes effect on September 13, 2021. ADDRESSES: Please refer to Docket ID NRC–2021–0038 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 NRC–2021–0038. Address questions about Docket IDs in Regulations.gov to Stacy Schumann; telephone: 301–415–0624; email: Stacy.Schumann@nrc.gov. For technical questions, contact the individuals listed SUMMARY: PO 00000 Frm 00044 Fmt 4703 Sfmt 9990 in the FOR FURTHER INFORMATION CONTACT section of this document. • NRC’s 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 NRC’s Public Document Room (PDR) reference staff at 1–800–397–4209, 301– 415–4737, or by email to pdr.resource@ nrc.gov. The ADAMS accession number for each document referenced (if it is available in ADAMS) is provided the first time that it is mentioned in this document. • 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 1– 800–397–4209 or 301–415–4737, between 8:00 a.m. and 4:00 p.m. (ET), Monday through Friday, except Federal holidays. RG 1.243 and the regulatory analysis may be found in ADAMS under Accession Nos. ML21089A032 and ML20339A559, respectively. Regulatory guides are not copyrighted, and NRC approval is not required to reproduce them. FOR FURTHER INFORMATION CONTACT: Edward O’Donnell, telephone: 301–415– 3317, email: Edward.ODonnell@nrc.gov and Marcos Rolon Acevedo, telephone: 301–415–2208, email: Marcos.RolonAcevedo@nrc.gov. Both are staff of the Office of Nuclear Regulatory Research at the U.S. Nuclear Regulatory Commission, Washington, DC 20555–0001. SUPPLEMENTARY INFORMATION: In the FR on September 7, 2021, in FR Doc. 2021– 19178, on page 50190, in the notice title after agency name correct ‘‘NRC–2020– 0038’’ to read ‘‘NRC–2021–0038.’’ In the ADDRESSES section, first sentence correct NRC Docket ID ‘‘NRC–2020–0038’’ to read ‘‘NRC–2021–0038’’ and in the first bullet of the ADDRESSES section, first sentence, correct ‘‘NRC–2020–0038’’ to read ‘‘NRC–2021–0038.’’ In the Additional Information section, correct ‘‘March 29, 2020’’ to read ‘‘March 29, 2021.’’ Dated: September 7, 2021. For the Nuclear Regulatory Commission. Meraj Rahimi, Branch Chief, Regulatory Guide and Programs Management Branch, Division of Engineering, Office of Nuclear Regulatory Research. [FR Doc. 2021–19621 Filed 9–10–21; 8:45 am] BILLING CODE 7590–01–P E:\FR\FM\13SEN1.SGM 13SEN1

Agencies

[Federal Register Volume 86, Number 174 (Monday, September 13, 2021)]
[Notices]
[Pages 50913-50914]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-19636]


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NUCLEAR REGULATORY COMMISSION

[NRC-2020-0237]


Considerations for Estimating Site-Specific Probable Maximum 
Precipitation at Nuclear Power Plants in the United States of America

AGENCY: Nuclear Regulatory Commission.

ACTION: NUREG; issuance.

-----------------------------------------------------------------------

SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing a 
knowledge management NUREG, NUREG/KM-0015, ``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/KM-0015 is available on September 13, 2021.

ADDRESSES: Please refer to Docket ID NRC-2020-0237 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 NRC-2020-0237. Address 
questions about Docket IDs in Regulations.gov to Stacy Schumann; 
telephone: 301-415-0624; email: [email protected]. For technical 
questions, contact the individual listed in the FOR FURTHER INFORMATION 
CONTACT section of this document.
     NRC's 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 NRC's Public 
Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or 
by email to [email protected]. NUREG/KM-0015, ``Considerations for 
Estimating Site-Specific 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 [email protected] or call 1-800-397-
4209 or 301-415-4737, 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 
20555-0001; telephone: 301-415-6809, email: [email protected].

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 50.54(f) 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 Near-Term 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 Permits and Combined Operating Licenses.
    In response to the staff's 2012 Sec.  50.54(f) 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 Sec.  50.54(f) 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 better-understand 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 staff's Sec.  50.54(f) 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

[[Page 50914]]

 Storm Representative Dew Point Selection
 Precipitable Water Estimation
 Dew Point Climatology, Moisture Maximization, and Moisture 
Transposition
 Terrain Adjustment
 Envelopment and Probable Maximum Precipitation Determination
 Spatial and Temporal Distributions for SSPMP Applications

    This reference document describes the technical theory, data 
sources, and analysis methodology that could be used to derive a SSPMP 
estimate. Certain new terms are also introduced and defined. This 
reference document also identifies key technical (meteorological) 
considerations when reviewing a SSPMP estimate.
    To date, there is no clear NRC guidance on this topic or a commonly 
agreed-to approach on the estimation of SSPMP. As the staff may be 
reviewing additional SSPMP estimates in the future in connection with 
its regulatory responsibilities, it was decided to elicit stakeholder 
views on the matters and approaches discussed in this draft document.
    This document contains no regulatory guidance or regulatory 
positions.
    A request for comments on draft NUREG/KM-0015, (ADAMS Accession No. 
ML20356A293) was published in the Federal Register on December 29, 2020 
(85 FR 85683), with a 60-day comment period ending on March 1, 2021. 
Comments received on NUREG/KM-0015 can be found on the Federal 
Rulemaking website (https://www.regulations.gov) under Docket ID NRC-
2020-0237.

II. Knowledge Management

    Since its inception, the Atomic Energy Commission and its 
successor, the NRC, have focused on preserving the (explicit) 
documentary record of its decision-making in the form of NUREGs, SECY 
Papers, Regulatory Guides, and other documents. However, in 2006, the 
agency recognized that there was a need to engage in a more-formal 
program of knowledge management that also reflects the less-tangible 
(implicit) human capital aspect of the agencies' knowledge base. This 
feature was particularly important as the agency enters its fifth 
decade of operation--a period characterized by an increasing number of 
retirements among long-serving staff involved in many of the agencies' 
early regulatory programs and associated licensing actions. Staff 
efforts thus far in preserving this legacy of experience that describe 
important historical events, facts, and research that were instrumental 
in shaping NRC's regulatory programs, can be found at https://www.nrc.gov/reading-rm/doc-collections/nuregs/knowledge/.
    The purpose of this knowledge management NUREG (or NUREG/KM) is 
intended to satisfy an NRC goal of maintaining and preserving knowledge 
concerning the lessons-learned from the recent flood hazard re-
evaluations at current and planned nuclear power plant sites performed 
most recently in connection with the staff 2012 Sec.  50.54(f) reviews.

    Dated: September 8, 2021.

    For the Nuclear Regulatory Commission.
Luissette Candelario-Quintana,
Project Manager, External Hazards Branch, Division of Engineering and 
External Hazards, Office of Nuclear Reactor Regulation.
[FR Doc. 2021-19636 Filed 9-10-21; 8:45 am]
BILLING CODE 7590-01-P