ML19140A447

Issuance of Amendments Revision to National Fire Protection Association (NFPA) Standard NFPA 805 Modifications

ML19140A447
Person / Time
Site:	Prairie Island
Issue date:	07/30/2019
From:	Robert Kuntz Plant Licensing Branch III
To:	Sharp S Northern States Power Company, Minnesota
Kuntz R 415-3733
References
EPID L-2018-LLA-0147
Download: ML19140A447 (28)

Text

July 30, 2019 Mr. Scott Sharp Site Vice President Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota 1717 Wakonade Drive East Welch, MN 55089

SUBJECT:

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 -

ISSUANCE OF AMENDMENTS NOS. 228 AND 216 RE: REVISION TO NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) STANDARD NFPA 805 MODIFICATIONS (EPID L-2018-LLA-0147)

Dear Mr. Sharp:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 228 to Renewed Facility Operating License No. DPR-42 and Amendment No. 216 to Renewed Facility Operating License No. DPR-60 for the Prairie Island Nuclear Generating Plant, Units 1 and 2 (PINGP), respectively. The amendments consist of changes to the licenses in response to your application dated May 18, 2018, as supplemented by letters dated July 10, 2018, December 6, 2018, and April 8, 2019.

The amendments revise the approved fire protection program (FPP). Specifically, the amendments deleted several modifications which are required as part of PINGPs implementation of its risk informed, performance-based fire protection program in accordance with paragraph 50.48(c) of Title 10 of the Code of Federal Regulations, National Fire Protection Association Standard 805.

A copy of our related safety evaluation is also enclosed. The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.

Sincerely,

/RA/

Robert F. Kuntz, Senior Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-282 and 50-306

Enclosures:

1. Amendment No. 228 to DPR-42

2. Amendment No. 216 to DPR-60

3. Safety Evaluation cc: Listserv

ML19140A447 *-memo dated **-via e-mai OFFICE DORL/LPL3/PM DORL/LPL3/LA DRA/APLB/BC NAME RKuntz SRohrer GCasto*

DATE 5/21/19 5/21/19 5/2/19 OGC NLO OFFICE DORL/LPL3/BC DORL/LPL3/PM w/comments NAME DRoth** LRegner (A) RKuntz DATE 6/24/19 7/11/19 7/30/19 NORTHERN STATES POWER COMPANY - MINNESOTA PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE DOCKET NO. 50-282 Amendment No. 228 License No. DPR-42

1. The U.S. Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by Northern States Power Company, a Minnesota Corporation (NSPM, the licensee), dated May 18, 2018, as supplemented by letters dated July 10, 2018, December 6, 2018, and April 8, 2019, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Renewed Facility Operating License No. DPR-42 is hereby amended to read as follows:

Enclosure 1

Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 228, are hereby incorporated in the renewed operating license.

NSPM shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of the date of its issuance and shall be implemented within 60 days.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Lisa M. Regner, Acting Branch Chief Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Renewed Facility Operating License Date of Issuance: July 30, 2019

NORTHERN STATES POWER COMPANY - MINNESOTA PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE DOCKET NO. 50-306 Amendment No. 216 License No. DPR-60

1. The U.S. Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by Northern States Power Company, a Minnesota Corporation (NSPM, the licensee), dated May 18, 2018, as supplemented by letters dated July 10, 2018, December 6, 2018, and April 8, 2019, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Renewed Facility Operating License No. DPR-60 is hereby amended to read as follows:

Enclosure 2

Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 216, are hereby incorporated in the renewed operating license.

NSPM shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of the date of its issuance and shall be implemented within 60 days.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Lisa M. Regner, Acting Branch Chief Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Renewed Facility Operating License Date of Issuance: July 30, 2019

ATTACHMENT TO LICENSE AMENDMENT NOS. 228 AND 216 RENEWED FACILITY OPERATING LICENSE NOS. DPR-42 AND DPR-60 PRAIRIE ISLAND NUCLEAR GENERATING PLANT DOCKET NOS. 50-282 AND 50-306 Replace the following pages of the Renewed Facility Operating License Nos. DPR-42 and DPR-60 with the attached revised pages. The changed areas are identified by a marginal line.

REMOVE INSERT Page 3 Page 3 Page 3 Page 3

(3) Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NSPM to receive, possess, and use at any time any byproduct, source and special nuclear material as sealed neutron sources for reactor startup, sealed sources for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required; (4) Pursuant to the Act and 10 CFR Parts 30, 40, and 70, NSPM to receive, possess and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument and equipment calibration or associated with radioactive apparatus or components; (5) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to possess but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility; (6) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to transfer byproduct materials from other job sites owned by NSPM for the purpose of volume reduction and decontamination.

C. This renewed operating license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR Chapter l:

Part 20, Section 30.34 of Part 30, Sections 50.54 and 50.59 of Part 50, and Section 70.32 of Part 70; is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level NSPM is authorized to operate the facility at steady state reactor core power levels not in excess of 1677 megawatts thermal.

(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 228, are hereby incorporated in the renewed operating license. NSPM shall operate the facility in accordance with the Technical Specifications.

(3) Physical Protection NSPM shall fully implement and maintain in effect all provisions of the Commission-approved physical security, guard training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.55 (51 FR 27817 and 27822) and to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The combined set of plans, which contains Renewed Operating License No. DPR-42 Amendment No. 228

(3) Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NSPM to receive, possess, and use at any time any byproduct, source and special nuclear material as sealed neutron sources for reactor startup, sealed sources for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required; (4) Pursuant to the Act and 10 CFR Parts 30, 40, and 70, NSPM to receive, possess and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument and equipment calibration or associated with radioactive apparatus or components; (5) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to possess but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility; (6) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to transfer byproduct materials from other job sites owned by NSPM for the purposes of volume reduction and decontamination.

C. This renewed operating license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR Chapter l:

Part 20, Section 30.34 of Part 30, Sections 50.54 and 50.59 of Part 50, and Section 70.32 of Part 70; is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level NSPM is authorized to operate the facility at steady state reactor core power levels not in excess of 1677 megawatts thermal.

(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 216, are hereby incorporated in the renewed operating license.

NSPM shall operate the facility in accordance with the Technical Specifications.

(3) Physical Protection NSPM shall fully implement and maintain in effect all provisions of the Commission-approved physical security, guard training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.55 (51 FR 27817 and 27822) and to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The combined set of plans, which contains Renewed Operating License No. DPR-60 Amendment No. 216

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 228 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-42 AND AMENDMENT NO. 216 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-60 NORTHERN STATES POWER COMPANY - MINNESOTA PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 DOCKET NOS. 50-282 AND 50-306

1.0 INTRODUCTION

By letter dated May 18, 2018 (Reference 1), as supplemented by letters dated July 10, 2018 (Reference 2), December 6, 2018 (Reference 3), and April 8, 2019 (Reference 4), Northern States Power Company - Minnesota, (NSPM, the licensee), submitted a license amendment request (LAR) regarding the Prairie Island Nuclear Generating Plant, Units 1 and 2 (PINGP).

Specifically, the licensee requested to delete several modifications which are required as part of PINGPs implementation of its risk-informed, performance-based, fire protection program (RI/PB FPP) in accordance with paragraph 50.48(c) of Title 10 of the Code of Federal Regulations (10 CFR) (National Fire Protection Association Standard 805 (NFPA 805)). The licensee included these modifications in Attachment S, Table S-2, which was submitted to the U.S.

Nuclear Regulatory Commission (NRC or Commission) in a letter dated December 14, 2016 (Reference 5).

The supplemental letters dated July 10, 2018, December 6, 2018, and April 8, 2019, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the NRC staffs original proposed no significant hazards consideration determination as published in the Federal Register (FR) on August 14, 2018 (83 FR 40350).

2.0 REGULATORY EVALUATION

2.1 Program Description In the 1990s, the NRC worked with the NFPA and industry to develop a RI/PB, consensus standard for fire protection. In 2001, the NFPA Standards Council issued NFPA 805, Performance-Based Standard for Fire Protection for Light Water Reactor [LWR] Electric Enclosure 3

Generating Plants (Reference 6), which describes a methodology for establishing fundamental FPP design requirements and elements, determining required fire protection systems and features, applying PB requirements, and administering fire protection for existing LWRs during operation, decommissioning, and permanent shutdown. It provides for the establishment of a minimum set of fire protection requirements but allows PB or deterministic approaches to be used to meet performance criteria. By letter dated August 9, 2017 (Reference 13) the NRC staff approved the adoption of NFPA-805 for PINGP.

2.2 Licensees Proposed Changes The LAR dated May 18, 2018, as supplemented by its letters dated July 10, 2018, December 6, 2018, and April 8, 2019, proposed to modify the PINGP NFPA 805 FPP by deleting modifications 15, 20, 27, 30, and 33 from Attachment S, Table S-2, of the December 14, 2016, letter which are required to be completed per Transition License Condition 2.C.(4)(c)2.

Modification item 15 requires installation of suction pressure protection for all the charging pumps to ensure adequate net positive suction head (NPSH) exists to prevent damage to the charging pumps. The modification item states that fire could damage cables causing multiple spurious operations resulting in damage to the charging pumps.

Modification item 20 requires installation of appropriate fuses and/or breakers to establish proper selective coordination for panels 136, 137, and 217. The modification item states that the current fire probabilistic risk assessment (FPRA) model assumes proper coordination exists for all credited power supplies and that per FPRA, credited power supplies lack selective coordination.

Modification item 27 requires installation of switches in the control room to isolate pressurizer power operated relief valves (PORVs), and pressurizer heaters. The licensee states that a fire in the control room (Fire Area 13) or the Relay and Cable Spreading Room (Fire Area 18) could cause spurious opening of valves that could lead to a loss of inventory.

Modification item 30 requires modification of risk significant cable (2DCA-10) from risk significant fire initiators in Fire Area 31. The modification item states that a fire in Fire Area 31 could damage cables that provide direct current (DC) power to vital auxiliaries which impacts risk.

Modification item 33 requires modification of cable 1DCB-18 from fire damage in Fire Area 32.

The modification item states that a fire in fire area 32 could damage the cable that provides DC control power to Panel 16 which supports instrumentation.

The licensee is also proposing a revision to its renewed facility operating license (RFOL),

paragraph 2.C(4)(c), Transition License Conditions, Item 2, which currently states:

The licensee shall implement the modifications to its facility as described in Attachment S, Table S-2, Plant Modifications Committed, in Northern States Power - Minnesota letter L-PI-16-090, dated December 14, 2016, to complete the transition to full compliance with 10 CFR 50.48(c), before the end of the second full operating cycle for each unit after approval of the LAR. The licensee shall maintain appropriate compensatory measures in place until completion of these modifications.

This LAR proposes revising the RFOL, paragraph 2.C(4)(c), Transition License Conditions, Item 2, to state (changes shown in bold):

The licensee shall implement the modifications to its facility as described in Attachment S, Table S-2, Plant Modifications Committed, in Northern States Power - Minnesota letter L-PI-18-005, dated May 18, 2018, to complete the transition to full compliance with 10 CFR 50.48(c), before the end of the second full operating cycle for each unit after approval of the NFPA 805 License Amendment dated August 8, 2017. The licensee shall maintain appropriate compensatory measures in place until completion of these modifications.

The change to the Transition License Conditions in RFOL, paragraph 2.C(4)(c), necessitates further changes in paragraph 2.C(4), Fire Protection. The current RFOL, paragraph 2.C(4), for each PINGP unit states:

NSPM shall implement and maintain in effect all provisions of the approved fire protection program that comply with 10 CFR 50.48(a) and 10 CFR 50.48(c), as specified in the licensee amendment request dated September 28, 2012 (and supplements dated November 8, 2012, December 18, 2012, May 3, 2013, October 17, 2013, April 30, 2014, May 28, 2015, June 19, 2015, October 6, 2015, October 22, 2015, January 20, 2016, May 24, 2016, August 17, 2016, December 14, 2016, and March 6, 2017), and as approved in the safety evaluation dated August 8, 2017. Except where NRC approval for changes or deviations is required by 10 CFR 50.48(c), and provided no other regulation, technical specification, license condition, or requirement would require prior NRC approval, the licensee may make changes to the fire protection program without prior approval of the Commission if those changes satisfy the provisions set forth in 10 CFR 50.48(a) and 10 CFR 50.48(c), the change does not require a change L-PI-18-005 NSPM to a technical specification or a license condition, and the criteria listed below are satisfied.

This LAR proposes revising the RFOL, paragraph 2.C(4), Fire Protection, to state (changes shown in bold):

NSPM shall implement and maintain in effect all provisions of the approved fire protection program that comply with 10 CFR 50.48(a) and 10 CFR 50.48(c), as specified in the licensee amendment requests dated September 28, 2012, and May 18, 2018 (and supplements dated November 8, 2012, December 18, 2012, May 3, 2013, October 17, 2013, April 30, 2014, May 28, 2015, June 19, 2015, October 6, 2015, October 22, 2015, January 20, 2016, May 24, 2016, August 17, 2016, December 14, 2016, March 6, 2017, July 10, 2018, December 6, 2018, and April 8, 2019), and as approved in the safety evaluations dated August 8, 2017, and [Safety Evaluation Date]. Except where NRC approval for changes or deviations is required by 10 CFR 50.48(c), and provided no other regulation, technical specification, license condition, or requirement would require prior NRC approval, the licensee may make changes to the fire protection program without prior approval of the Commission if those changes satisfy the provisions set forth in 10 CFR 50.48(a) and 10 CFR 50.48(c),

the change does not require a change to a technical specification or a license condition, and the criteria listed below are satisfied.

2.3 Regulatory Requirements The following regulations address fire protection:

10 CFR 50.48, Fire protection, provides the NRC requirements for nuclear power plant fire protection. The NRC regulations include specific requirements for requesting approval for a RI/PB FPP based on the provisions of NFPA 805.

Section 50.48(a)(1) of 10 CFR requires that each holder of an operating license have a FPP that satisfies General Design Criterion (GDC) 3, Fire Protection, of Appendix A to 10 CFR Part 50, General Design Criteria for Nuclear Power Plants.

Section 50.48(c) of 10 CFR incorporates NFPA 805 (2001 Edition) by reference, with certain exceptions, modifications, and supplementation. This regulation establishes the requirements for using an RI/PB FPP in conformance with NFPA 805 as an alternative to the requirements associated with 10 CFR 50.48(b) and Appendix R, Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979, to 10 CFR Part 50, or the specific plant fire protection license condition. The regulation also includes specific requirements for requesting approval for an RI/PB FPP based on the provisions of NFPA 805.

Paragraph 50.48(c)(3)(i) of 10 CFR states, that:

A licensee may maintain a fire protection program that complies with NFPA 805 as an alternative to complying with [10 CFR 50.48(b)] for plants licensed to operate before January 1, 1979, or the fire protection license conditions for plants licensed to operate after January 1, 1979.

The licensee shall submit a request to comply with NFPA 805 in the form of an application for license amendment under § 50.90. The application must identify any orders and license conditions that must be revised or superseded, and contain any necessary revisions to the plants technical specifications and the bases thereof. The Director of the Office of Nuclear Reactor Regulation, or a designee of the Director, may approve the application if the Director or designee determines that the licensee has identified orders, license conditions, and the technical specifications that must be revised or superseded, and that any necessary revisions are adequate. Any approval by the Director or the designee must be in the form of a license amendment approving the use of NFPA 805 together with any necessary revisions to the technical specifications.

Appendix A to 10 CFR Part 50, GDC 3, states, in part, that:

Structures, systems, and components important to safety shall be designed and located to minimize, consistent with other safety requirements, the probability and effect of fires and explosions.

Noncombustible and heat resistant materials shall be used wherever practical throughout the unit, particularly in locations such as the containment and control room.

Section 4.2.4.2 of NFPA 805 states that the [u]se of fire risk evaluation for the performance-based approach shall consist of an integrated assessment of the acceptability of risk, defense-in-depth [DID], and safety margins.

As a supplement to the definition of DID provided in NFPA 805, Section 1.2, the NRC-endorsed guidance in NEI [Nuclear Energy Institute] 04-02, Section 5.3.5.2, states, in part, that:

In general, the DID requirement is satisfied if the proposed change does not result in a substantial imbalance in:

Preventing fires from starting Detecting fires quickly and extinguishing those that do occur, thereby limiting fire damage Providing adequate level of fire protection for structures, systems and components important to safety, so that a fire that is not promptly extinguished will not prevent essential plant safety functions [from] being performed.

Appendix A, Section A.2.4.4.3, provides the following background related to the meaning of the term safety margins:

An example of maintaining sufficient safety margins occurs when the existing calculated margin between the analysis and the performance criteria compensates for the uncertainties associated with the analysis and data.

Another way that safety margins are maintained is through the application of codes and standards. Consensus codes and standards are typically designed to ensure such margins exist.

Section 5.3.5.3, Safety Margins, of NEI 04-02, Revision 2, lists two specific criteria that should be addressed when considering the impact of plant changes on safety margins:

Codes and standards or their alternatives accepted for use by the NRC are met, and, Safety analysis acceptance criteria in the licensing basis (e.g., FSAR [Final Safety Analysis Report], supporting analyses) are met, or provides sufficient margin to account for analysis and data uncertainty.

In addition, 10 CFR 50.32, Elimination of repetition, states, in part, that the applicant may incorporate by reference information contained in previous applications, statements or reports filed with the Commission: Provided, That such references are clear and specific.

2.4 Applicable Codes, Standards, and Regulatory Guides The 2001 edition of NFPA 805, Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants, specifies the minimum fire protection requirements for existing light water NPPs during all phases of plant operations, including shutdown, degraded conditions, and decommissioning. NFPA 805 was developed to provide a comprehensive RI/PB standard for fire protection. The

NFPA 805 Technical Committee on Nuclear Facilities is composed of nuclear plant licensees, the NRC, insurers, equipment manufacturers, and subject matter experts.

The scope of NFPA 805 includes goals related to nuclear safety, radioactive release, life safety, and plant damage/business interruption. The standard addresses fire protection requirements for nuclear plants during all plant operating modes and conditions, including shutdown and decommissioning, which had not been explicitly addressed by previous requirements and guidelines. NFPA 805 became effective on February 9, 2001.

Revision 1 of Regulatory Guide (RG) 1.205, Risk-Informed, Performance-Based Fire Protection for Existing Light Water Nuclear Power Plants, December 2009 (Reference 7), provides guidance for use in complying with the requirements that the NRC has promulgated for RI/PB FPPs that comply with 10 CFR 50.48 and the referenced 2001 Edition of the NFPA standard. Revision 1 of RG 1.205 sets forth regulatory positions; clarifies the requirements of 10 CFR 50.48(c) and NFPA 805, clarifies the guidance in Nuclear Energy Institute (NEI) 04-02, Revision 2, Guidance for Implementing a Risk-Informed, Performance-Based Fire Protection Program Under 10 CFR 50.48(c),

April 2008, and provides exceptions to the NEI 04-02 guidance.

Revision 3 of RG 1.174 (Reference 8), An Approach for Using Probabilistic Risk Assessment in Risk Informed Decisions on Plant-Specific Changes to the Licensing Basis, provides the NRC staffs recommendations for using risk information in support of licensee-initiated licensing basis changes to a nuclear power plant that require such review and approval.

NUREG/CR-6850, EPRI/NRC-RES Fire PRA [Probabilistic Risk Assessment]

Methodology for Nuclear Power Facilities, Volumes 1 and 2, and Supplement 1, September 2005 and September 2010 (Reference 9), (Reference 10), (Reference 11),

respectively, present a compendium of methods, data, and tools to perform an FPRA and develop associated insights.

NEI 04-02 (Reference 12), provides guidance for implementing the requirements of 10 CFR 50.48(c), and represents methods for implementing in whole or in part a RI/PB FPP. This implementing guidance for NFPA 805 has two primary purposes: (1) provide direction and clarification for adopting NFPA 805 as an acceptable approach to fire protection, consistent with 10 CFR 50.48(c); and (2) provide additional supplemental technical guidance and methods for using NFPA 805 and its appendices to demonstrate compliance with fire protection requirements. Although there is a significant amount of detail in NFPA 805 and its appendices, clarification and additional guidance for select issues help ensure consistency and effective utilization of the standard. The NEI 04-02 guidance focuses attention on the RI/ PB FPP fire protection goals, objectives, and performance criteria contained in NFPA 805 and the RI/PB tools considered acceptable for demonstrating compliance. Revision 2 of NEI 04-02 incorporates guidance from RG 1.205 and NRC issued Frequently Asked Questions (FAQs).

3.0 TECHNICAL EVALUATION

3.1 Discussion In accordance with 10 CFR 50.48(c)(3)(i), the licensee submitted an LAR to revise its fire protection License Condition 2.C.(4). The NRC staff reviewed the information provided in the LAR including discussions of the impact of the proposed changes on risk, DID, and safety margins, which are required by NFPA 805, Section 4.2.4.2.

The LAR dated May 18, 2018, as supplemented by letters dated July 10, 2018, December 6, 2018 and April 8, 2019, proposed to modify the NFPA 805 FPP by deleting Modifications 15, 20, 27, 30, and 33, and to also revise its FPP license condition.

The LAR included:

a summary of all changes to the modifications; a summary of all changes to the PRA models and explanations for each change; new, updated versions in their entirety include: the license condition (Attachment M), list of plant modifications (Attachment S), and the summarizing area wide change-in-risk result tables (Attachment W); and a statement that the DID and safety margin evaluations associated with the original LAR have been completed on the proposed changes.

The LAR stated that the plant modifications have been evaluated using the accepted FPRA methods and approaches as summarized in the final safety evaluation (SE) accompanying the license amendment dated August 8, 2017, approving transition to NFPA 805 (the NFPA 805 SE).

Based on the information provided in the LAR, as discussed below, the NRC staff determined that the licensee evaluated the proposed changes to the plant modifications using the accepted FPRA methods and approaches as summarized in the NFPA 805 SE, and incorporated several NUREGs containing acceptable approaches that were not previously incorporated into the FPRA (e.g. NUREG-2169, NUREG-2178, and NUREG-2180).

LAR Section 2.4, Attachment W Changes, describes many changes to the FPRA, some of which the NRC staff has determined do not have a direct relationship to the modifications presented in this LAR, but affect the PRA quantification. These changes to the FPRA are based on the NUREGs mentioned above, and expansions to the standard technical tasks performed in developing a FPRA. In particular, the licensee applied NUREG-2169, Nuclear Power Plant Fire Ignition Frequency and Non-Suppression Probability Estimation Using the Updated Fire Events Database, (Reference 14), and NUREG-2178, Refining And Characterizing Heat Release Rates from Electrical Enclosures During Fire (RACHELLE-FIRE), (Reference 15), which resulted in the use of new fire frequencies, new suppression values and new heat release rates (HRRs). The licensee applied NUREG-2180, Determining the Effectiveness, Limitations, and Operator Response for Very Early Warning Fire Detection Systems in Nuclear Facilities, (Delores-VEWFIRE), Final Report, (Reference 16), to model very early warning fire detection systems (VEWFDS), which replaces NFPA 805 FAQ 08-0046, Closure of National Fire Protection Association 805 Frequently Asked Question 08-0046: Incipient Fire Detection Systems, (Reference 17), that was used in the original NFPA 805 LAR. Additional work was done by the licensee to modify the standard PRA modeling tasks of equipment selection, fire

induced risk model, cable selection and detailed circuit failure analysis, circuit failure mode likelihood analysis, scoping and detailed fire modeling (FM), post-fire human reliability analysis, and fire risk quantification. Each of these cited PRA tasks were completed at various levels of detail as described in the original NFPA 805 LAR, and each change to those tasks cited in this LAR refines or improves the original analysis.

The licensee performed a focused scope peer review of the cable thermal response methodology it applied (Appendix H of NUREG/CR-6850) since use of this methodology was considered a PRA upgrade. The licensee indicated that no findings were identified during the peer review. The NFPA 805 SE cites this approach and finds it acceptable, and since the peer review made no findings, the NRC staff finds this approach acceptable for use in the PRA.

As permitted by 10 CFR 50.32, the LAR references methods and approaches used in support of PINGP Amendment Nos. 220 and 207, or other methods and approaches that the NRC staff considers acceptable. Additionally, because the NRC staff has found these methods and approaches acceptable for evaluating changes to the FPP as described in the NFPA 805 SE or in NRC guidance documents, the NRC staffs review in support of this proposed license amendment need not reevaluate the acceptable methods and approaches.

The LAR states that DID involves the following three echelons: (1) preventing fires from starting; (2) rapidly detecting, controlling and promptly extinguishing those fires that do occur, thereby, preventing fire damage; and (3) providing adequate level of fire protection for systems and structures so that a fire will not prevent essential safety functions from being performed.

The LAR states that safety margins are maintained in the fact that:

fire detection and fire suppression systems credited in NFPA 805, Chapter 4, have been evaluated to meet the requirements of NFPA 805, Chapter 3, and their associated codes of record for those systems or provided with acceptable alternatives using processes accepted for use by the NRC.

the RI/PB processes used are based upon NFPA 805, as endorsed by the NRC in 10 CFR 50.48(c).

the fire risk evaluation (FRE) process is in accordance with NEI 04-02 endorsed by RG 1.205 and clarified by Frequently Asked Question (FAQ) 07-0030, Establishing Recovery Actions, (Reference 19).

the FPRA was developed with guidance from NUREG/CR-6850 which was developed jointly between the NRC and the Electric Power Research Institute (EPRI).

the internal events PRA (IEPRA) and FPRA have received a formal industry peer review based on the NEI guidelines in order to ensure the FPRA meets the appropriate standards of American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS) Standard ASME/ANS RA-Sa-2009, Addenda to ASME/ANS RA-S-2008 Standard for Level 1/Large Early Release Frequency [LERF] Probabilistic Risk Assessment for Nuclear Power Applications (Reference 20).

the peer review of the FPRA model was conducted by a diverse group of PRA practitioners from other PWR [pressurized-water reactor] plants and industry.

FM performed in support of the transition has been performed within the FPRA utilizing codes and standards developed by industry and NRC staff which have been verified and validated in authoritative publications, such as NUREG-1824, Verification and Validation of Selected Fire Models for Nuclear Power Plant Applications (Reference 21).

In regard to safety margins, the NRC staff confirmed that the proposed changes continue to maintain adequate safety margins, because as discussed above, the changes do not impact any codes and standards, or their alternatives accepted for use by the NRC, and the changes do not impact any safety analysis acceptance criteria used in the licensing basis.

3.2 Delete Charging Pump Suction Pressure Protection Modification (modification 15)

The LAR dated September 28, 2012 (Reference 18), to adopt NFPA 805 includes modification 15 to install suction pressure protection for all the charging pumps to ensure adequate NPSH exists to prevent damage to the charging pumps.

The LAR dated May 18, 2018, proposed not to complete modification 15 because the modification to install suction pressure protection for charging pumps no longer provides significant risk benefit to warrant the modification because the FPRA model was updated to better reflect plant system response. The LAR further stated that the volume control tank (VCT) outlet motor operated valves will be de-energized to preclude spurious closure in the event of a fire.

3.2.1 Summary of Modification The LAR states that this proposed modification is to protect the charging pumps from inadequate NPSH and that the normal letdown flow path flows into the VCT is the normal source to the positive displacement charging pumps for the volume control system. The LAR further states that spurious isolation of the letdown flow path would stop the flow into the VCT and level would drop, and that if the charging pumps are not stopped and the refueling water storage tank (RWST) supply valve failed to open on low VCT level, the VCT water inventory would be depleted and the charging pumps would no longer function as intended. The LAR further states that the FPRA model includes an operator action to open the RWST supply to the charging pumps and that once the RWST supply valve is open, the elevation head of the RWST remains larger than the head of the VCT for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at charging pump flow rates, and therefore, closing the VCT outlet valve is not time critical. The LAR further states that the FPRA model was updated to remove credit for the modification by deleting the basic events and fault tree gates that were added to credit the modification, and that the results remain acceptable and are presented in the new Attachment W tables provided in Enclosure 6 of the LAR.

3.2.2 DID The LAR states that DID is maintained after the deletion of this modification for charging pump suction protection because it does not impact the ability to prevent fires from starting, nor does it impact the ability to rapidly detect, control, and extinguish fires that do occur. The LAR further states that an adequate level of fire protection is maintained because the opening of the VCT supply valve breaker will preclude spurious isolation of the VCT supply and that an operator action exists to open the RWST supply to the charging pumps, thus, closing the VCT outlet valve is not time critical. The LAR further states that the VCT outlet valves will be de-energized to preclude spurious closure in the event of a fire and the failure of the RWST supply valve to open is still modeled in the FPRA.

3.2.3 NRC Staff Evaluation The LAR indicated that methods and approaches were used as summarized in the NFPA 805 SE for the current evaluations. Besides the general changes in the PRA based on accepted approaches described in various NUREGs, and refinements and improvements to the overall FPRA quantification, the PRA was restructured for this modification to remove certain failures and better reflect operator actions and plant system response, which the NRC staff finds is an acceptable manipulation of a PRA model. Thus, the NRC staff finds that the methods and approaches used in this modification from the original NFPA 805 SE are acceptable for use in the integrated PRA assessment.

In regard to DID, the NRC staff confirmed the proposed changes have no impact on any of the DID echelons because not completing the modification has no impact on preventing fires from starting, or detecting or extinguishing fires, and because an adequate level of fire protection will continue to be provided so that a fire will not prevent essential safety functions from being performed. Because the DID echelons are unaffected, the NRC staff concludes that the balance between DID echelons is maintained.

3.3 Delete Panels 136, 137, and 217, Breaker Coordination Modification (Modification 20)

The LAR dated September 28, 2012, to adopt NFPA 805, includes Modification 20 to install the appropriate fuses and/or breakers to establish proper selective coordination for Panels 136, 137, and 217.

The LAR dated May 18, 2018, proposes not to complete Modification 20 because the FPRA model was updated to include failure of the un-coordinated load cables as causing a failure of the upstream uncoordinated supply breaker, which causes a loss of power for Panels 136 and 137 that lack selective fuse/breaker coordination. The LAR further states that the FPRA no longer credits a recovery action (RA) to transfer the source breaker for Panel 211 or Panel 213 to Panel 217 to restore power to these instrument buses due to a fire in Fire Area 31 and, therefore, electrical coordination between the main fuse and the upstream circuit breaker of Panel 217 is not required to support this RA, however, this action remains as a DID action.

3.3.1 Summary of Modification The LAR states that Panel 217 was previously credited to be an alternate power supply to alternating current (AC) Instrument Panels 211 and 213 in the event of fire damage to the normal AC power supply to Panels 211 or 213. The LAR further states that Panels 211 and 213 support process monitoring indications in the main control room (MCR) and that loss of power to these panels results in degraded instrumentation. The LAR further states that the FPRA model considers the degraded instrumentation impact in these fire scenarios and that since Panel 217 is no longer credited to re-power Panels 211 and 213 in the event of a fire, the lack of electrical coordination on Panel 217 has no impact for Panels 211 and 213.

The LAR states that Panels 136 and 137 provide AC power to the cooling water strainers backwash controller and the diesel driven cooling water pumps (DDCLPs) fuel oil transfer pumps, and that loss of power to the cooling water strainers backwash control results in loss of automatic backwash of the cooling water strainers upon high differential pressure. The LAR further states that a calculation was performed which demonstrates this is not a time critical function and the strainers will not significantly obstruct cooling water flow during the mission

time and, therefore, RAs are no longer required for the cooling water strainers and Panels 136 and 137 are not required to support the cooling water strainers.

The LAR states that the diesel fuel oil transfer pumps for the DDCLPs are powered from Panels 136 and 137 and provide fuel oil from underground storage tanks to the 12 DDCLP (Train A) and 22 DDCLP (Train B) day tanks, respectively, and that there are also three motor driven cooling water pumps (11, 21, and 121) that supply cooling water to the cooling water header.

The LRA further states un-coordinated load cables are mapped to failing the upstream panels in the FPRA model and, therefore, the impact of lack of coordination is included in the FPRA model.

The LAR states that the additional risk due to lack of electrical coordination on Panels 136, 137, and 217, has been incorporated into the FPRA model and it incorporated the results in the new Attachment W.

3.3.2 DID The LAR states that DID is maintained after the deletion of this modification for breaker coordination because it does not impact the ability to prevent fires from starting, nor does it impact the ability to rapidly detect, control, and extinguish fires that do occur. The LAR further states that an adequate level of fire protection is maintained because the impact of the lack of electrical coordination is included in the FPRA model and the results remain acceptable.

With regards to the response to PRA RAI 01 (Reference 22), on DID echelon 3, the request for additional information (RAI) response states that repowering Panels 211 and 213 from Panel 217 to provide process monitoring indication in the MCR is a DID action. The RAI response further states that while a lack of electrical coordination on Panel 217 exists between the main fuse and the upstream circuit breaker, electrical coordination is achieved with the branch fuses and main fuse. The NRC staff required further clarification to the response to PRA RAI 01 regarding the coordination between the branch fuses and the supply breaker upstream of the main fuse, and the licensee responded, that for Fire Area 31, the area of interest, that the fuses for the branch circuit are also coordinated with the upstream supply circuit breaker. Based on the information provided by the licensee, the NRC staff concludes that Panel 217 will remain available to support repowering Panels 211 and 213, and that DID is maintained.

The NRC requested additional information about DID echelon 3 for Panels 136 and 137.

Panels 136 and 137 provide power to the cooling water strainer backwash function. The licensee responded by letter dated December 8, 2018, that cooling water flow will be available to support essential safety functions for the mission time without the cooling water strainer backwash function. The RAI response provided a discussion that concluded that there are no fire areas for which loss of power to Panels 136 and 137 for the fuel oil transfer pumps to the DDCLPs result in an inability to achieve safe and stable conditions. Based on the information provided by the licensee, the NRC staff concludes that DID is maintained for this change to the previously accepted NFPA 805.

3.3.3 NRC Staff Evaluation The LAR, as supplement, states that the FPRA no longer credits a RA to transfer the source breaker for Panel 211 or Panel 213 to Panel 217 to restore power to these instrument buses due to a fire in Fire Area 31. Since the NFPA 805 SE discusses accepted methods to perform

this change to the PRA, the NRC staff finds that the methods and approaches used for this change are acceptable for use in the integrated PRA assessment.

In regard to DID, the NRC staff confirmed that DID is maintained for the proposed change because not completing the modification has no impact on preventing fires from starting, or detecting or extinguishing fires, and because an adequate level of fire protection will continue to be provided so that a fire will not prevent essential safety functions from being performed.

Thus, the NRC staff concludes that the balance between DID echelons is maintained.

3.4 Delete Pressurizer PORVs and Heaters Control Switch Modification (Modification 27)

The LAR dated September 28, 2012, to adopt NFPA 805 includes Modification 27 to install switches in the control room to isolate pressurizer PORVs, and pressurizer heaters.

The LAR dated May 18, 2018, proposes to not complete Modification 27 because a detailed circuit analysis was performed on the process control inputs to the pressurizer level and pressure control system that provides automatic signals to the pressurizer PORVs and pressurizer heaters. The LAR further states that previously, relays were assumed to be failed in the most adverse position, and that now, the signal and control cables that impact the relays are mapped and only failed in the applicable scenarios. The LAR further states that it credited an additional RA to manually operate pressurizer heater breakers outside the control room in alternate shutdown procedures after control room abandonment.

3.4.1 Summary of Modification The LAR states that the FPRA model was updated to remove credit for new control room isolation switches, include the detailed circuit analysis for the pressurizer heaters and PORVs, and include credit for RAs outside the control room to locally operate pressurizer heater breakers. The LAR further states that operator action to close the pressurizer PORVs from the control room is credited to isolate spurious pressure signals if the pressurizer PORVs control switches and cables have not been impacted by the fire and that the existing action to isolate pressurizer PORVs outside the MCR is also still credited for alternate shutdown scenarios.

The LAR further states that the FPRA results remain acceptable with credit for the modification to pressurizer PORVs and heater circuits removed and that the results are included in the new Attachment W.

3.4.2 DID/Safety Margins The LAR states that DID is maintained after the deletion of this modification for isolation switch installation because it does not impact the ability to prevent fires from starting, nor does it impact the ability to rapidly detect, control, and extinguish fires that do occur. The licensee further stated that an adequate level of fire protection is maintained because the spurious operation of the pressurizer PORVs and pressurizer heaters is mitigated by actions outside the MCR to isolate these spurious events and the risk of these actions is included in the FPRA model.

3.4.3 NRC Staff Evaluation The LRA indicated that acceptable methods were used as discussed in the NFPA 805 SE for the current evaluations. Besides the general changes in the PRA based on accepted

approaches in NUREGs and refinements and improvements to the overall FPRA quantification, several actions were taken for this modification. Typical changes to the PRA to remove former credit in the PRA were performed; worst-case failure assumptions from fire induced damage to relays were revised. Additionally, accepted human reliability analysis methods discussed in the NFPA 805 SE were applied to credit an additional RA to manually operate pressurizer heater breakers outside the MCR in alternate shutdown procedures after MCR abandonment. Thus, the NRC staff finds that the methods and approaches used for this modification are based on acceptable methods and approaches discussed in the NFPA 805 SE, and these PRA methods and approaches are acceptable for use in the integrated PRA assessment.

In regard to DID, the NRC staff confirmed the proposed change has no impact on any of the DID echelons because not completing the modification has no impact on preventing fires from starting, or detecting or extinguishing fires, because an adequate level of fire protection will continue to be provided so that a fire will not prevent essential safety functions from being performed. Because the DID echelons are unaffected, the NRC staff concludes that the balance between DID echelons is maintained.

3.5 Delete Cable 2DCA-10 Modification (Modification 30)

The LAR dated September 28, 2012, to adopt NFPA 805 includes Modification 30 to modify risk significant cable (2DCA-10) from risk significant fire initiators in Fire Area 31.

The LAR dated May 18, 2018, proposed to not complete Modification 30 because the licensee stated that cable 2DCA-10 provides DC power to PINGP, Unit 2, Train A, DC, Panel 25, which powers relays that provide automatic start of the 21 motor driven auxiliary feed water (AFW) pump on low steam generator (SG) level or safety injection (SI) signal, but operators can still start the 21 AFW pump from the control room. The LAR further states that the protection of cable 2DCA-10 was a risk reduction modification and is not a variance from deterministic requirement (VFDR) of NFPA 805.

3.5.1 Summary of Modification The LAR states that the 21 AFW pump starts due to the following signals: SI signal; low SG level; both main feedwater pumps tripped; anticipated transient without a scram (ATWS) mitigating system actuation circuitry (AMSAC)/diverse scram system (DSS); and manual start by operators. The LAR further states that the main feedwater system and AMSAC/DSS start signals are not credited in the FPRA model due to dependency on other systems like instrument air and service building support systems that are not credited in the FPRA model. The LAR further states that DC power from Panel 25 is required for the AFW start relays for the SI signal and the low SG level start signal and that failure of the automatic start signal to the 21 AFW pump would require operators to manually start the 21 AFW pump from the control room. The LAR further states that the FPRA results remain acceptable with credit for the modification to cable 2DCA-10 removed and the results are included in the new Attachment W.

3.5.2 DID The LAR states that DID is maintained after the deletion of this modification for cable 2DCA-10 because it does not impact the ability to prevent fires from starting, nor does it impact the ability to rapidly detect, control, and extinguish fires that do occur. The LAR further stated that an adequate level of fire protection is maintained because modifications (Table S-2, items 2 and 4) were performed to the PINGP, Unit 2, AFW system to remove the A Train controls from Fire

Area 31 and, therefore, the A Train of the AFW system now remains available to provide flow to the SGs in the event of a fire in Fire Area 31.

3.5.3 NRC Staff Evaluation The LAR indicates that acceptable methods were used as discussed in the NFPA 805 SE for the current evaluations. Besides the general changes in the PRA based on accepted approaches in NUREGs and refinements and improvements to the overall FPRA quantification, the cable 2DCA-10 is now modeled in the PRA as susceptible to fire induced damage. Failing functions in the PRA due to cable damage is done typically in the FPRA. Thus, the NRC staff finds that the methods and approaches used for this modification are based on acceptable methods and approaches discussed in the NFPA 805 SE, and these PRA methods and approaches are acceptable for use in the integrated PRA assessment.

In regard to DID, the NRC staff confirmed the proposed change has no impact on any of the DID echelons because not completing the modification has no impact on preventing fires from starting, or detecting or extinguishing fires, and because an adequate level of fire protection will continue to be provided so that a fire will not prevent essential safety functions from being performed. Because the DID echelons are unaffected, the NRC staff concludes that the balance between DID echelons is maintained.

3.6 Delete Cable 1DCB-18 Modification (Modification 33)

In the LAR dated September 28, 2012, to adopt NFPA 805, the licensee included Modification 33 to modify cable 1DCB-18 from fire damage in Fire Area 32.

The LAR dated May 18, 2018, proposed to not complete modification 30 because cable 1DCB-18 provides DC power to PINGP, Unit 1, Train B, DC, Panel 16, which powers relays that provide automatic start of the 12 motor driven AFW pump on low SG level or SI signal, but operators can still start the 12 AFW pump from the control room. The LAR further stated that protection of cable 1DCB-18 was a risk reduction modification and is not a VFDR of NFPA 805 because the 12 AFW pump remains available from the control room to provide AFW to the SGs.

3.6.1 Summary of Modification The LAR states that the 12 AFW pump starts due to the following signals: SI signal; low SG level; both main feedwater pumps tripped; AMSAC/DSS; and manual start by operators. The LAR further states that the main feedwater system and the AMSAC/DSS start signals are not credited in the FPRA model due to dependency on other systems like instrument air and service building support systems that are not credited in the FPRA model. The LAR further states that DC power from Panel 16 is required for the AFW start relays for the SI signal and the low SG level start signal and that failure of the automatic start signal to the 12 AFW pump would require operators to manually start the 12 AFW pump from the control room. The LAR further states that the FPRA results remain acceptable with credit for the modification to cable 1DCB-18 removed and the results are included in the new Attachment W.

3.6.2 DID/Safety Margins The LAR states that DID is maintained after the deletion of this modification for cable ADCB-18 because it does not impact the ability to prevent fires from starting, nor does it impact the ability to rapidly detect, control, and extinguish fires that do occur. The LAR further stated that an

adequate level of fire protection is maintained because modifications (Table S-2, items 2 and 4) were performed to the PINGP, Unit 1, Train B, AFW pump remains available to be manually started from the control room and, therefore, the AFW system now remains available to provide flow to the SGs in the event of a fire in Fire Area 32.

3.6.3 NRC Staff Evaluation The LAR indicated that acceptable methods were used as discussed in the NFPA 805 SE for the current evaluations. Besides the general changes in the PRA based on accepted approaches in NUREGs and refinements and improvements to the overall FPRA quantification, the cable 1DCB-18 is now modeled in the PRA as susceptible to fire induced damage. Failing functions in the PRA due to cable damage is done typically in the FPRA. Thus, the NRC staff finds that the methods and approaches used for this modification are based on acceptable methods and approaches from the NFPA 805 LAR, and these PRA methods and approaches are acceptable for use in the integrated PRA assessment.

In regard to DID, the NRC staff confirmed the proposed change has no impact on any of the DID echelons because not completing the modification has no impact on preventing fires from starting, or detecting or extinguishing fires, and because an adequate level of fire protection will continue to be provided so that a fire will not prevent essential safety functions from being performed. Because the DID echelons are unaffected, the NRC staff concludes that the balance between DID echelons is maintained.

3.7 Conclusion The NRC staff reviewed the LAR that asked not to be required to complete five modifications, and to revise its license conditions related to the RI/PB FPP in accordance with the requirements of 10 CFR 50.48(c) and NFPA 805. The changes proposed in the LAR included a review of risk, DID, and safety margins as required by NFPA 805, Section 4.2.4.2.

The LAR identified revisions to license conditions in accordance with 10 CFR 50.48(c)(3)(i).

The NRC staff concludes that the LAR provides the appropriate license conditions that must be revised as a result of the proposed changes, and that the revisions are adequate, thereby, satisfying the requirements of 10 CFR 50.48(c)(3)(i).

The NRC staff determined that: (1) the effect of the proposed changes on the FPP could be assessed using the methods and approaches previously approved by the NRC staff, and (2) acceptable methods to change the PRA were used including those changes from NUREG-2169, NUREG-2178, NUREG-2180, and NUREG/CR-6850, Appendix H, to produce the risk estimates.

In addition to the consideration of methods and approaches discussed above, the NRC staff inquired about statements in the LAR regarding the review of negative change in risk contained in Attachment W, Section W.2.4. The letter dated July 10, 2018, states that multiple cutsets containing a specific circuit failure mode likelihood analysis (CFMLA) were adding up to more than 1.0 in the compliant case. The July 10, 2018, letter also indicates that the software code used to create the variant plant model inadvertently omitted one query that should have applied CFMLA to certain scenarios. The letter further states that the software code used to create the compliant plant model included all of the required queries that apply CFMLA. The NRC staff found that CFMLA was applied inconsistently between quantifications of the compliant and

variant plant models. The July 10, 2018, letter states that once the CFMLA was applied equally to both quantifications, the negative delta-risk was eliminated.

The LAR indicates that multiple failure mode cutsets that appeared to be minimal but were related to the same component failure were investigated. The LAR states that the FPRA model was updated such that the CFMLA was applied at the component level instead of the basic event level so that one cutset was generated for each component failure.

The LAR indicated that the improper query issue could affect more than those fire areas with a negative delta risk, and as a result, the LAR provided a revised Attachment W.

The total core damage frequency (CDF) which contains the effects of fire, seismic, and internal events and internal floods are 8.66E-05 and 8.62E-05 for PINGP, Units 1 and 2, respectively.

The total large early release probability (LERF) which contains the effects of fire, seismic, and internal events and internal floods are 1.18E-06 and 1.11E-06 for PINGP, Units 1 and 2, respectively. The change in CDF is 3.99E-06 and 9.44E-06 for PINGP, Units 1 and 2, respectively. The change in LERF is 5.48E-08 and 1.10E-07 for PINGP, Units 1 and 2, respectively. The additional CDF for RAs is 2.99E-06 and 6.62E-06 for PINGP, Units 1 and 2, respectively. The additional LERF for RAs is 4.40E-08 and 8.04E-08 for PINGP, Units 1 and 2, respectively. Thus, the NRC staff concludes that the change in CDF and LERF meet the acceptance guidelines in RG 1.174 for both units, and the additional risk of RAs meets the acceptance guidelines in RG 1.205 for both units.

The NRC staff concludes that the results of the licensees evaluation in regard to risk, DID, and safety margin for the proposed changes are acceptable because: (1) the changes when integrated into the PRA produce an increase in the change in CDF and in the change in LERF, and with the total CDF and LERF that fall within the RG 1.174 risk acceptance guidelines; (2) the licensees process and results followed guidance approved by the NRC staff in its NFPA 805 SE or other guidance documents; and (3) the results of the changes are consistent with guidance in NEI 04-02, Revision 2; RG 1.205, Revision 1; and RG 1.174, Revision 3.

Implementation of the RI/PB FPP under 10 CFR 50.48(c) must be in accordance with the fire protection license condition, which identifies the list of modifications and implementation items that must be completed in order to support the NRC staffs conclusion and establishes a date by which full compliance with 10 CFR 50.48(c) must be achieved. Before the licensee is able to fully implement the transition to an FPP based on NFPA 805 and apply the new fire protection license condition to its full extent, the modifications and implementation items must be completed within the timeframe specified.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Minnesota State official was notified of the proposed issuance of the amendments on May 17, 2019. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendments change the requirements with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or change the surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in the amounts, no significant change in the types of any effluents that may

be released offsite, and no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding August 14, 2018 (83 FR 40350). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b),

no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.

6.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.

7.0 REFERENCES

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2. Sharp, Scott, Northern States Power Company - Minnesota, letter to U.S. Nuclear Regulatory Commission, "Supplement to License Amendment Request to Revise License Condition Associated with Implementation of NFPA 805 (EPID L-2018-LLA-0147)," July 10, 2018 (ADAMS Accession No. ML18191B265).

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19. Klein, Alexander, R., U.S. Nuclear Regulatory Commission, "Close-Out of National Fire Protection Association Frequently Asked Question 07-0030 On Establishing Recovery Actions," February 4, 2011 (ADAMS Accession No. ML110070485).

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21. U.S. Nuclear Regulatory Commission, NUREG-1824, "Verification and Validation of Selected Fire Models for Nuclear Power Plant Applications," May 2007. Volume 1: Main Report, Volume 2: Experimental Uncertainty, Volume 3: Fire Dynamics Tools (FDTS),

Volume 4: Fire-Induced Vulnerability Evaluation (FIVE-Revision 1), Volume 5: Consolidated Fire Growth and Smoke Transport Model (CFAST), Volume 6: MAGIC, and Volume 7: Fire Dynamics Simulator (ADAMS Accession Nos. ML071650546, ML071730305, ML071730493, ML071730499, ML071730527, ML071730504, ML071730543, respectively).

22. Kuntz, Robert, U.S. Nuclear Regulatory Commission, E-Mail to Gohdes, Peter, D., Northern States Power Company - Minnesota, "Request for Additional Information RE: Prairie Island NFPA-805 License Condition Modification Amendment Request," November 7, 2018 (ADAMS Accession No. ML18313A083).

Principal Contributors: Jay Robinson, NRR JS Hyslop, NRR Date of issuance: July 30, 2019