[Federal Register Volume 78, Number 38 (Tuesday, February 26, 2013)]
[Notices]
[Pages 13097-13099]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-04396]
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NUCLEAR REGULATORY COMMISSION
[NRC-2013-0038]
Electric Power Research Institute; Seismic Evaluation Guidance
AGENCY: U.S. Nuclear Regulatory Commission.
ACTION: Endorsement letter; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an
endorsement letter with clarifications of Electric Power Research
Institute (EPRI)-1025287, ``Seismic Evaluation Guidance: Screening,
Prioritization and Implementation Details (SPID) for the Resolution of
Fukushima Near-Term Task Force Recommendation 2.1: Seismic,'' Revision
0, hereafter referred to as the SPID report. This SPID report provides
guidance and clarification of an acceptable approach to assist nuclear
power reactor licensees when responding to the NRC staff's request for
information dated March 12, 2012, Enclosure 1, ``Recommendation 2.1:
Seismic.'' The NRC staff's endorsement
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letter includes additional clarifications on the: (1) Use of the
Individual Plant Examination of External Events (IPEEE) submittals for
screening purposes; (2) development of foundation input response
spectra (FIRS) consistent with the site response used in the
development of the site-specific ground motion response spectrum
(GMRS); (3) updating the seismic source models; and (4) development of
the site response.
ADDRESSES: You may access information related to this document, which
the NRC possesses and is publicly available, by searching on http://www.regulations.gov under Docket ID NRC-2013-0038.
Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2013-0038. Address
questions about NRC dockets to Carol Gallagher; telephone: 301-492-
3668; email: [email protected].
NRC's Agencywide Documents Access and Management System
(ADAMS): You may access publicly-available documents online in the NRC
Library at http://www.nrc.gov/reading-rm/adams.html. To begin the
search, select ``ADAMS Public Documents'' and then 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]. The NRC staff's endorsement
letter is available under ADAMS Accession No. ML12319A074. The NRC
staff's request for information dated March 12, 2012, Enclosure 1,
``Recommendation 2.1: Seismic'' is available under ADAMS Accession No.
ML12053A340.
NRC's PDR: You may examine and purchase copies of public
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555
Rockville Pike, Rockville, MD 20852.
FOR FURTHER INFORMATION CONTACT: Mrs. Lisa M. Regner, Japan Lessons-
Learned Project Directorate, Office of Nuclear Reactor Regulation, U.S.
Nuclear Regulatory Commission, Washington, DC 20555-0001; telephone:
301-415-1906; email: [email protected].
SUPPLEMENTARY INFORMATION:
Background Information
The endorsement letter for the SPID report is being issued to the
public to describe guidance that is acceptable for responding to the
request to reevaluate seismic hazards at operating reactor sites, as
discussed in Enclosure 1 ``Recommendation 2.1: Seismic,'' of the NRC
staff's request for information (RFI), ``Request for Information
Pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Part
50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term
Task Force Review of Insights from the Fukushima Dai-ichi Accident,''
dated March 12, 2012.
The NRC issued the RFI following the NRC staff's evaluation of the
earthquake and tsunami, and resulting nuclear accident, at the
Fukushima Dai-ichi nuclear power plant in March 2011. Enclosure 1 to
the RFI requests licensees and holders of construction permits under 10
CFR Part 50, to reevaluate the seismic hazards at their sites using
present-day NRC requirements and guidance, and identify actions taken
or planned to address plant-specific vulnerabilities associated with
the updated seismic hazards. Based on this information, the NRC staff
will determine whether additional regulatory actions are necessary to
protect against the updated hazards. The principal purpose of the SPID
report is to provide guidance for responding to the RFI by describing
strategies for screening, prioritization, and potential interim
actions, as well as implementation guidance for the risk evaluation
that are acceptable to the NRC staff.
Basis for Endorsement
The NRC staff interacted with the stakeholders on development of
the SPID report with a focus on screening, prioritization, and
implementation details as they relate to performing a seismic
reevaluation. The SPID report is the product of significant interaction
between the NRC, Nuclear Energy Institute, EPRI, and other stakeholders
at over fifteen public meetings \1\ over a 9-month period. These
interactions and the insights gained from the meetings allowed for the
development of this document in a very short time frame. The meetings
helped develop the expectations for how licensees would perform plant
evaluations after having updated their seismic hazard information. At
each meeting, the NRC staff provided its comments on the current
version of the SPID report and discussed with stakeholders subsequent
proposed revisions to the document. This iterative process, over
several months, resulted in the final version of the document. The NRC
staff's endorsement of the SPID report, subject to the additional
guidance noted below, is based on this cumulative development process
resulting from the extensive interactions between stakeholders and the
NRC staff.
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\1\ Public meetings were held on March 1-2, April 2-3, May 15-
16, June 14, July 24-25, August 16 and 30, September 11 and 21,
October 9 and 18, November 5, 9, 14, 20, and 26, 2012.
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The NRC staff has reviewed the SPID report and confirmed that it
would provide licensees with the guidance necessary to perform seismic
reevaluations and report the results to the NRC in a manner that will
address the Requested Information items (1) through (9) in Enclosure 1
of the 50.54(f) letter. The SPID report is intended to provide
sufficient guidance for all sites, however, each site is unique and
requirements for analysis can vary. In cases where the SPID report may
not account for the unique characteristics of a site, prudent and sound
engineering judgment should be employed to assure all issues bearing on
the hazard and risk evaluations are adequately addressed. Instances
when unique site characteristics require such engineering judgment, or
require analysis that is not included in the SPID report, should be
clearly identified, along with the measures taken to assure the unique
site characteristics are appropriately addressed. Although the NRC
staff finds that the performance and reporting of the seismic
reevaluation in accordance with this document would be responsive to
the 50.54(f) letter, there are four further issues described below for
which the staff provides additional guidance. These issues are: (1) The
use of the IPEEE submittals for screening purposes; (2) development of
FIRS consistent with the site response used in the development of the
site-specific GMRS; (3) updating the seismic source models; and (4)
development of the site response.
Use of IPEEE for Screening
Section 3.3 of the EPRI guidance document provides the criteria
used to determine if the licensee's previous IPEEE submittal is
adequate to use for screening purposes. A seismic assessment performed
as part of the IPEEE program that demonstrates a plant capacity that is
higher than the new GMRS can be used to screen out plants, provided
they meet certain adequacy criteria.
Each licensee has the option of demonstrating the adequacy of its
previous IPEEE submittal for screening purposes as part of its response
to the 50.54(f) letter. The NRC staff will review each submittal and
determine whether the provided information demonstrates the adequacy of
the IPEEE analysis and risk insights. The licensee's description of
each of the adequacy criteria, described in Section 3.3 of the SPID
report, will be reviewed by the NRC staff in its integrated totality,
rather than using a pass/fail approach. As such,
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even if one or more of the criteria are not deemed to be adequate, the
NRC staff may still decide that the overall IPEEE analysis is adequate
to support its use for screening purposes. The NRC staff may conduct
site visits to view IPEEE documentation referenced in support of the
IPEEE adequacy submittal.
Development of FIRS
The SPID report does not discuss the development of FIRS used for
performing soil-structure interaction analyses. Consistent with
guidance described in DC/COL-ISG-017, ``Ensuring Hazard-Consistent
Seismic Input for Site Response and Soil Structure Interaction
Analyses,'' the FIRS should be derived in a manner consistent with the
site response used in the development of the site-specific GMRS. As
such, the FIRS should be derived as performance-based site-specific
response spectra at the foundation level in the free field. The
starting point for development of the FIRS should be the same hard rock
elevation used as the starting point for developing the GMRS. As the
engineering properties of soil are strain-dependent and can be highly
non-linear, the characterization of soil layers and their associated
properties used in the GMRS analysis should also be used for the
derivation of the site-specific FIRS at the foundation elevation. The
performance-based FIRS can be developed using either a full-column
outcrop motion that includes the effect of the soil above, or as a
geologic outcrop motion for which the soil layers above the foundation
elevation have been removed.
Updating the Central and Eastern United States (CEUS)-Seismic Source
Characterization (SSC) Model
Section 2.2 of the SPID report provides an overview of the CEUS-SSC
model and explains why it is appropriate to use without update for the
seismic reevaluations. Specifically, Section 2.2 states ``for site-
specific licensing applications or site-specific safety decisions,
these seismic sources would be reviewed on a site-specific basis to
determine if they need to be updated. Such evaluations would be
appropriate in a licensing application, where focus could be made on
site-specific applications. However, for a screening-level study of
multiple plants for the purpose of setting priorities, the use of these
seismic sources as published is appropriate.''
The NRC staff agrees that the CEUS-SSC model does not need to be
updated for the seismic reevaluations, but the staff's rationale is
different than that presented in the SPID report. Specifically, the
staff has determined that the CEUS-SSC model does not need to be
updated because the model is up-to-date and is sufficiently refined to
allow a site-specific source model to be developed. To adequately
respond to the 50.54(f) letter, a site-specific GMRS should be
calculated for each plant so that an informed decision can be made
regarding which plants will be required to complete a risk evaluation.
Further, the site-specific GMRS will also be used in the risk
evaluations.
Prior to issuing the CEUS-SSC model, the Technical Integration Team
considered potentially significant events (such as the 2011 Mineral, VA
earthquake) that had occurred after the model was developed, and
determined that those events did not change their interpretations of
seismic sources or earthquake recurrence rates. If a significant
earthquake in the CEUS were to occur or new information were to emerge
during the reevaluation period that could require an update of the
CEUS-SSC model, the staff expects licensees to evaluate the
significance of the new information to determine if the CEUS-SSC model
needs to be updated in order to appropriately respond to the 50.54(f)
request.
Site Response
Section 2.4.1 and Appendix B of the SPID report provides guidance
on how to develop the site response in cases where limited site
response data exists. As stated in Appendix B, the NRC staff expects
licensees to use available geologic, geotechnical, and geophysical data
collected during the initial licensing or subsequent activities at the
site to the extent practicable. Where limited site response data
exists, information from core borings and data collected from site and
regional evaluations should be used to develop the site response
amplification. Section 4 of the SPID report states that licensees
should provide the basis for the site responses used in the
reevaluations. The NRC staff expects site-specific geology,
geotechnical, and geophysical information to be a significant part of
the basis.
Non-Concurrence
An NRC staff member did not agree with some content of the SPID
report and submitted a non-concurrence on the SPID endorsement letter.
In accordance with the NRC's non-concurrence process, NRC management
and staff worked to address the staff member's concerns, and
documentation of the non-concurrence can be found in ADAMS at Accession
No. ML12324A195.
60-Day Response
In accordance with the 50.54(f) letter, each licensee is to submit
to the NRC its intention to follow the NRC-endorsed seismic
reevaluation guidance, or an alternative approach, 60 days after the
issuance of the NRC-endorsed guidance. For the purpose of meeting this
deadline, the 60-day response period commences on the date the
endorsement letter is published in the Federal Register.
Backfitting and Issue Finality
This endorsement letter does not constitute backfitting as defined
in 10 CFR 50.109 (the Backfit Rule) and is not otherwise inconsistent
with the issue finality provisions in Part 52, ``Licenses,
Certifications, and Approvals for Nuclear Power Plants,'' of 10 CFR.
This endorsement letter provides guidance on an acceptable method for
implementing the March 12, 2012, RFI. Applicants and licensees may
voluntarily use the guidance in the SPID report, as clarified by the
NRC staff in the endorsement letter, to comply with the RFI. Methods,
analyses, or solutions that differ from those described in the SPID
report may be deemed acceptable if they provide sufficient basis and
information for the NRC staff to verify that the proposed alternative
is acceptable.
Congressional Review Act
This endorsement letter is a rule as designated in the
Congressional Review Act (5 U.S.C. 801-808). The Office of Management
and Budget has found that this is a major rule in accordance with the
Congressional Review Act.
Dated at Rockville, Maryland, this 15th day of February 2013.
For the Nuclear Regulatory Commission.
David L. Skeen,
Director, Japan Lessons-Learned Project Directorate, Office of Nuclear
Reactor Regulation.
[FR Doc. 2013-04396 Filed 2-25-13; 8:45 am]
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