ML17151A337
ML17151A337 | |
Person / Time | |
---|---|
Site: | Mcguire, McGuire ![]() |
Issue date: | 06/02/2017 |
From: | Rosenberg S NRC/NRR/DRA |
To: | Markley M Division of Operating Reactor Licensing |
Zeehung Gary, NRR/DRA 301-415-1686 | |
References | |
CAC MF9673, CAC MF9674 | |
Download: ML17151A337 (6) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 2, 2017
MEMORANDUM TO: Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
FROM: Stacey L. Rosenberg, Chief
/RA/ Probabilistic Risk Assessment Licensing Branch Division of Risk Assessment Office of Nuclear Reactor Regulation
SUBJECT:
RECOMMENDATION FOR NON-ACCEPTANCE WITH OPPORTUNITY TO SUPPLEMENT OF MCGUIRE NUCLEAR
STATION UNITS 1 AND 2 TECHNICAL SPECIFICATION COMPLETION TIME EXTENSION REQUEST FOR FAILURE TO
SUPPLY INFORMATION (CACs MF9673, MF9674)
By letter dated May 2, 2017 (Agencywide Documents Access and Management System
[ADAMS] Accession No. ML17122A116), Duke Energy Carolinas, LLC (Duke Energy) submitted a license amendment request (LAR) to revise Technical Specification (TS) 3.8.1, "AC Sources -
Operating," to revise the Required Actions (RA) and diesel generator Completion Time (CT)
extension for an inoperable diesel generator for Catawba Nuclear Station (CNS), Units 1 and 2
and McGuire Nuclear Station (MNS), Units 1 and 2.
Review of the proposed LAR is performed in accordance with Regulatory Guide (RG) 1.177, Revision 1, "An Approach for Plant-Specific, Risk-Informed Decision-making: Technical
Specifications," and RG 1.174, Revision 2, "An Approach for using Probabilistic Risk
Assessment in Risk-Informed Decisions on Plant Specific Changes to the Licensing Basis."
Review of the technical acceptability of the PRA is performed in accordance with RG 1.200, Revision 2, "An Approach for Determining the Technical Adequacy of Probabilistic Risk
Assessment Results for Risk-Informed Activities," issued in March 2009. Regulatory Issue
Summary 2007-06, "Regulatory Guide 1.200 Implementation," issued March 22, 2007, clarifies
how the NRC staff will incorporate successive revisions to RG 1.200 that might change the
process of, or the basis for, the NRC staff's review of the technical acceptability of a PRA.
CONTACT: Zeechung Gary Wang, NRR/DRA (301) 415-1686
Enclosure:
Basis for non-acceptance
The purpose of this letter is to provide the results of the NRC staff's acceptance review of this
amendment request. The purpose of the acceptance review is to determine if there is sufficient
technical information in scope and depth to allow the NRC staff to complete its detailed
technical review. In addition, the acceptance review is intended to identify whether the
application has any readily apparent information insufficiencies in its characterization of the
regulatory requirements or the licensing basis of the plant.
The Probabilistic Risk Assessment Licensing Branch (APLA) reviewed the proposed TS change
and has concluded that the information contained in the licensee's application is not sufficient
for review. The basis for the staff's decision is enclosed.
The NRC staff has included in the enclosure to this letter information it deems is necessary to
enable the staff to make an independent assessment regarding the acceptability of the
proposed amendment request in terms of regulatory requirements and the protection of public
health and safety and the environment.
ML17151A337 OFFICE NRR/DRA/APLB NRR/DRA/APLA NRR/DRA/APLA NAME GWang THilsmeier SRosenberg DATE 5/25/2017 5/31/2017 6/2/2017
ENCLOSURE RECOMMENDATION FOR NON-ACCEPTANCE WITH OPPORTUNITY TO SUPPLEMENT OF MCGUIRE NUCLEAR STATION UNITS 1 AND 2 TECHNICAL SPECIFICATION COMPLETION TIME EXTENSION REQUEST FOR FAILURE TO SUPPLY INFORMATION (CACs MF9673, MF9674)
As stated in Office Instruction LIC-109, "Acceptance Review Procedures", it is the policy of the Office of Nuclear Reactor Regulation (NRR) to review an application to amend a license for
completeness and acceptability for docketing. The quality of a requested licensing action (RLA)
has a significant impact on the amount of NRC staff's resources expended in the review
process. When an application lacks critical information necessary for the NRC staff to complete
its review, an excessive amount of NRC staff time is spent gathering this information. As a
result, time spent on RLAs that are unacceptable for review results in longer review periods for
the RLA and adversely impacts the resources and schedules of other acceptable RLAs. In
accordance with LIC-109, and in conjunction with Regulatory Guide (RG) 1.177, Revision 1, "An
Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications," and RG
1.174, Revision 2, "An Approach for using Probabilistic Risk Assessment in Risk-Informed
Decisions on Plant Specific Changes to the Licensing Basis," the Probabilistic Risk Assessment (PRA) Licensing Branch (APLA) has completed the acceptance review of the license
amendment request (LAR), and has concluded that the McGuire internal events risk analysis
that supports the requested change does not include sufficient information to enable the NRC
staff to make an independent assessment regarding PRA quality in a timely and efficient
manner.
When a licensee requests an amendment to its license that involves a risk-informed change to
technical specifications, RG 1.177 states that when the risk associated with a particular hazard
group or operating mode would affect the decision being made, it is the Commission's policy
that, if a staff-endorsed PRA standard exists for that hazard group or operating mode, then the
risk will be assessed using a PRA that meets that standard. Regulatory Guide 1.174 adds that
a qualitative treatment of the missing modes and hazard groups may be sufficient when the
licensee can demonstrate that those risk contributions will not affect the decision; that is, they
do not alter the results of the comparison with the acceptance guidelines. In March of 2009, the
NRC issued Revision 2 of RG 1.200, "An Approach for Determining the Technical Adequacy of
Probabilistic Risk Assessment Results for Risk-Informed Activities," which endorsed industry
standards for PRAs for internal events, internal floods, fires, and external events (i.e., seismic, external flooding, high winds, etc.). The NRC staff position provided in RIS 2007-06 allows one
year before revisions to RG 1.200 are expect ed to be implemented in a licensee's PRA model that is used as a basis for risk-informed LARs.
Regulatory Basis
Section 2.3.1, "Technical Adequacy of the PRA," of RG 1.177, Revision 1, states:
The technical adequacy of the PRA must be compatible with the safety
implications of the TS [technical specification] change being requested and the
role that the PRA plays in justifying that change.
2 ENCLOSURE That is, the more the potential change in risk or the greater the uncertainty in that risk from the requested TS change, or both, the more rigor that must go into
ensuring the technical adequacy of the PRA.
The licensee may address the technical adequacy of the PRA by conforming to the peer
review and self-assessment processes in RG 1.200, Revision 2. This regulatory guide
provides one approach acceptable to the NRC for determining the technical adequacy of
the PRA model. Regulatory Guide 1.200 endorses, with certain clarifications and
qualifications, Addendum A to the American Society of Mechanical Engineers/American
Nuclear Society (ASME/ANS) RA-Sa 2009, "Standard for Probabilistic Risk Assessment
for Nuclear Power Plant Applications" ("PRA Standard").
Section 4.2, "Licensee Submittal Documentation," of RG 1.200 states, in part, that the
application should discuss the resolution of the peer review facts and observations (F&Os) that
are applicable to the parts of the PRA required for the application. This should include: (1) a
discussion of how the PRA model has been changed, and (2) justification in the form of a
sensitivity study that demonstrates the accident sequences or contributors significant to the
application decision were not adversely impacted (remained the same) by the particular issue.
One acceptable approach for closing F&Os so that they need not be provided in submissions of
risk-informed licensing applications is to implement the process accepted by NRC's letter to
Nuclear Energy Institute dated May 3, 2017 (Agencywide Documents Access and Management System [ADAMS] Accession No. ML17079A427). Following this process will reinforce the NRC
staff's confidence in the F&O closure process and potentially obviate the need for a more in-
depth review.
Issue Discussion In Attachment 6, Section 6.1.3 of the LAR, "PRA Quality/Technical Adequacy," the licensee
indicates that most of the F&Os found during the June 2015 peer review of the internal events
PRA (excluding large early release frequency, LERF) were assessed by an independent review
team in January 2016 to be adequately resolved based on the updated internal events PRA.
Therefore, these F&Os were not submitted in the LAR. However, as discussed with the
licensee on May 17, 2017 concerning the submission of these F&Os for the McGuire LAR for
Integrated Leakage Rate Test, the close-out of these F&Os occurred well before the guidance
on this process was finalized and accepted by NRC letter dated May 3, 2017 (ADAMS
Accession No. ML17079A427). Therefore, it is uncertain whether the licensee closed these
F&Os consistent with NRC-accepted guidance, and that these F&Os should have been
submitted as part of the LAR.
3 ENCLOSURE Request for Supplemental Information The NRC staff finds that the part of the LAR pertaining to McGuire Nuclear Station, Units 1 and
2, does not meet the acceptability standards as outlined in LIC-109 and other guidelines. The
application lacks critical information in this area necessary for the NRC staff to complete its
review without an excessive amount of NRC staff time and resources. Therefore, the staff
concludes that to be consistent with Section 4.2 of RG 1.200, Revision 2, and to demonstrate
the technical adequacy of the McGuire internal events PRA (excluding LERF) against RG 1.200
at Capability Category II, the licensee provide (a) or (b) below for acceptability of this
application:
(a) Provide all F&Os characterized as findings from the June 2015 peer review of the internal events PRA (excluding LERF). For each F&O, include details of its disposition
or why not meeting the corresponding Capability Category II requirements has no impact
on the application.
(b) Alternatively, discuss the close out of the F&Os by the January 2016 independent review of the internal events PRA (excluding LERF), which evaluated the technical adequacy of
the additional analysis performed to address the F&Os from the 2015 peer review. This
discussion should be consistent with that of the "Final Report" developed in accordance with Section X.1.3, "Close Out F&Os by Independent Assessment," of the Nuclear
Energy Institute letter dated February 21, 2017 (ADAMS Accession No. ML17086A431).