ML16189A328

NRC Plan for the Audit of Exelon Generation'S Mitigation Strategies Assessment Submittals Relating to Order EA-12-049 for Braidwood Station, Dresden Nuclear Power Station, Peach Bottom Units 2 and 3, and Three Mile Island, Unit 1

ML16189A328
Person / Time
Site:	Dresden, Peach Bottom, Three Mile Island, Braidwood
Issue date:	07/12/2016
From:	Tekia Govan Japan Lessons-Learned Division
To:	Bryan Hanson Exelon Generation Co
References
CAC MF7898, CAC MF7899, CAC MF7921, CAC MF7922, CAC MF7958, CAC MF7959, CAC MF7984
Download: ML16189A328 (6)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C . 20555-0001 July 12, 2016 Mr. Bryan C. Hanson President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville , IL 60555

SUBJECT:

NUCLEAR REGULA TORY COMMISSION PLAN FOR THE AUDIT OF EXELON GENERATION COMPANY, LLC'S MITIGATION STRATEGIES ASSESSMENT SUBMITTALS RELATING TO ORDER EA-12-049, "ORDER TO MODIFY LICENSES WITH REGARD TO REQUIREMENTS FOR MITIGATION STRATEGIES FOR BEYOND-DESIGN-BASIS EXTERNAL EVENTS ," FOR BRAIDWOOD STATION, UNITS 1 AND 2 (CAC NOS . MF7898 AND MF7899) ;

DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 (CAC NOS. MF7921 AND MF7922) ; PEACH BOTTOM ATOMIC POWER STATION , UNITS 2 AND 3 (CAC NOS. MF7958 AND MF7959) ; AND THREE MILE ISLAND NUCLEAR STATION , UNIT 1 (CAC NO. MF7984) .

Dear Mr. Hanson:

This letter documents the U.S. Nuclear Regulatory Commission (NRC) staff's plan to perform regulatory audits of Exelon Generation Company, LLC's (the licensee) Mitigation Strategies Assessment (MSA) submittals related to Order EA-12-049, "Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events,"

(Agencywide Documents Access and Management System (ADAMS) Accession No. ML12054A735) for the following plants:

• Braidwood Station, Units 1 and 2 (Braidwood)

• Dresden Nuclear Power Station, Units 2 and 3 (Dresden)

• Peach Bottom Atomic Power Station, Units 2 and 3 (Peach Bottom)

• Three Mile Island Nuclear Station , Unit 1 (Three Mile Island).

These technical audits will be performed consistent with NRC Office of Nuclear Reactor Regulation Office Instruction LIC-111 , "Regulatory Audits ," dated December 29, 2008 (ADAMS Accession No. ML082900195) . The audits will be conducted over multiple sessions, as needed, and the NRC staff will develop an audit summary report to document its observations and conclusions within 90 days of the final audit session.

The audits will provide the NRC staff with a better understanding of the MSAs. Specifically, the audits will be used to confirm that the MSA submitted by the licensee has adequately addressed the reevaluated hazards within its mitigation strategies for beyond-design-basis external events.

B. Hanson The enclosed audit plan outlines the process that will allow the NRC staff to identify additional information potentially necessary for licensees to supplement their MSAs, and resolve any potential technical concerns . The details of this audit have been discussed with Mr. Dave Distel of your staff.

If you have any questions, please contact me at (301) 415-6197 or by e-mail at Tekia.Govan@nrc.gov.

Sincerely, Juu °'- \[~{0-----

Tekia V. Govan, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. :

Braidwood: STN 50-456 and STN 50-457 Dresden : 50-237 and 50-249 Peach Bottom : 50-277 and 50-278 Three Mile Island : 50-289

Enclosure:

Audit Plan cc w/encl : Distribution via Listserv

NRC PLAN FOR THE AUDIT OF EXELON GENERATION COMPANY, LLC'S MITIGATION STRATEGIES ASSESSMENT SUBMITTALS RELATING TO ORDER EA-12-049 FOR MULTIPLE PLANTS BACKGROUND AND AUDIT BASIS:

By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No ML12053A340), the NRC issued a request for information pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The 50.54(f) letter was issued as part of the lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 2 to the 50.54(f) letter requested that licensees reevaluate flood-causing mechanisms using present-day methodologies and guidance. Concurrent with the reevaluation of flood hazards, licensees were required to develop and implement mitigating strategies using the most recent external hazard information in accordance with NRC Order EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML12054A735). That order requires holders of operating reactor licenses and construction permits issued under 10 CFR Part 50 to modify the plants to provide additional capabilities and defense-in-depth for responding to beyond-design-basis external events, and to submit to the NRC for review a final integrated plan that describes how compliance with the requirements of Attachment 2 of the order was achieved. In order to proceed with implementation of Order EA-12-049, licensees used the current licensing basis flood hazard or the most recent flood hazard information, which may not be based on present day-methodologies and guidance, in the development of their mitigating strategies.

The NRC staff and industry recognized the difficulty in developing and implementing mitigating strategies before completing the reevaluation of flood hazards. The NRC staff described this issue and provided recommendations to the Commission on integrating these related activities in COMSECY-14-0037 , "Integration of Mitigating Strategies for Beyond-Design-Basis External Events and the Reevaluation of Flood Hazards," dated November 21 , 2014 (ADAMS Accession No. ML14309A256). The Commission issued a staff requirements memorandum on March 30, 2015 (ADAMS Accession No. ML15089A236), affirming that the Commission expects licensees for operating nuclear power plants to address the reevaluated flood hazards, which are considered beyond-design-basis external events, within their mitigating strategies.

Exelon Generation Company, LLC (Exelon , the licensee) submitted its Mitigation Strategies Assessment (MSA) for the following plants:

Braidwood Station , Units 1 and 2, by letter dated June 30, 2016 (ADAMS Accession No ML16182A378)

Dresden Nuclear Power Station , Units 2 and 3, by letter dated June 30, 2016 (ADAMS Accession No. ML16182A388)

Peach Bottom Atomic Power Station, Units 2 and 3, by letter dated June 30, 2016 (ADAMS Accession No. ML16182A009)

Three Mile Island Nuclear Station, Unit 1, by letter dated June 29, 2016 (ADAMS Accession No. ML16181A202)

Enclosure

The NRC staff has begun its review of the aforementioned submittals and plans to conduct regulatory audits of Exelon to aid in its review of the licensee's MSAs.

REGULA TORY AUDIT SCOPE AND METHODOLOGY Nuclear Energy Institute (NEI) 12-06, Revision 2, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide" (ADAMS Accession No. ML16005A625), has been endorsed by the NRC as an appropriate methodology for licensees to perform assessments of the mitigating strategies against the reevaluated flood hazards developed in response to the March 12, 2012, 50.54(f) letter. The guidance in NEI 12-06, Revision 2, and Appendix G in particular, supports the proposed Mitigation of Beyond-Design-Basis Events rulemaking. The endorsement, including exceptions, clarifications, and additions, is described in NRC Japan Lessons-Learned Division (JLD) interim staff guidance (ISG) JLD-ISG-2012-01, Revision 1, "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML15357A163).

Therefore, Appendix G of NEI 12-06, Revision 2, describes acceptable methods for demonstrating that the reevaluated flooding hazard is addressed within the assessments of mitigating strategies for beyond-design-basis external events.

INFORMATION AND OTHER MATERIAL NECESSARY FOR THE REGULATORY AUDIT:

The areas of focus for the regulatory audit is the information contained in the MSA submittals, and all associated and relevant supporting documentation used in the development of the aforementioned document including, but not limited to, methodology, process information, calculations , computer models, etc.

NRC AUDIT TEAM:

Title Team Member Affiliation Team Leader, NRR/JLD Tekia Govan NRC Branch Chief, NRR/JLD/JHMB Gregory Bowman NRC Branch Chief, NRR/JLD/JOMB Mandy Halter NRC Branch Chief, NRR/JLD/JERB Stewart Bailey NRC Branch Chief, NRR/JLD/JCBB Jessie Quichocho NRC Technical Staff, NRR/JLD Various Staff Members NRC LOGISTICS:

The audit meetings will be coordinated with Exelon staff.

DELIVERABLES:

The NRC team will develop an audit summary report to convey the audit results. The report will be placed in ADAMS within 90 days of the completion of the final audit session, and will be publicly available.

B. Hanson The information discussed in the audit may be included , fully or in part, in the development of the NRC staff's evaluation of the MSA review.

B. Hanson The enclosed audit plan outlines the process that will allow the NRC staff to identify additional information potentially necessary for licensees to supplement their MSAs, and resolve any potential technical concerns . The details of this audit have been discussed with Mr. Dave Distel of your staff.

If you have any questions, please contact me at (301) 415-6197 or by e-mail at Tekia.Govan@nrc.gov.

Sincerely, IRA/

Tekia V. Govan, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos.:

Braidwood: STN 50-456 and STN 50-457 Dresden: 50-237 and 50-249 Peach Bottom: 50-277 and 50-278 Three Mile Island : 50-289

Enclosure:

Audit Plan cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC JLD R/F RidsNRRJLD Resource GBowman , NRR MShams, NRR MHalter, NRR TGovan , NRR SBailey, NRR JQuichocho, NRR RidsNrrDorlLPL 1-2 RidsNrrDorlLPL3-2 RidsNrrPMBraidwoodResource RidsNrrPMDresdenResource RidsNrrPMPeachBottomResource RidsN rrPMThreeMilelslandResource ADAMS Accession No.: ML16189A328 *via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/JHMB/LA NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME TGovan Slent GBowman TGovan DATE 07/08/2016 07/08/2016 07/10/2016 07/12/2016 OFFICAL RECORD COPY