ML19305A005

Issuance of Amendment No. 217 National Fire Protection Association Standard (NFPA) 805 Program Revisions

ML19305A005
Person / Time
Site:	Summer
Issue date:	03/06/2020
From:	Shawn Williams Plant Licensing Branch II
To:	Stoddard D South Carolina Electric & Gas Co
Williams S, NRR/DORL/LPLLPL
References
EPID L-2018-LLA-0233
Download: ML19305A005 (52)

Text

March 6, 2020 Mr. Daniel G. Stoddard Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Blvd., Floor: IN-2SW Glen Allen, VA 29060

SUBJECT:

VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 ISSUANCE OF AMENDMENT NO. 217, RE: NATIONAL FIRE PROTECTION ASSOCIATION STANDARD (NFPA) 805 PROGRAM REVISIONS (EPID L-2018-LLA-0233)

Dear Mr. Stoddard:

The U.S. Nuclear Regulatory Commission (the Commission) has issued the enclosed Amendment No. 217 to Renewed Facility Operating License No. NPF-12 for the Virgil C.

Summer Nuclear Station, Unit No. 1, (Summer) in response to your application dated August 29, 2018, as supplemented by letters dated April 29, 2019, May 22, 2019, August 12, 2019, and October 9, 2019.

The amendment revises license conditions and approves revisions to Summers NFPA 805 licensing basis. Revisions include approval of changes to the fire probabilistic risk assessment model, approval of performance-based alternatives to NFPA 805, Section 3.3.4, Insulation Materials, and Section 3.3.5.1, Wiring above Suspended Ceilings, and approval of plant modifications. The amendment also approves clarification and editorial corrections to the NFPA 805 safety evaluation dated February 11, 2015.

A copy of the related Safety Evaluation is also enclosed. Notice of Issuance will be included in the Commissions biweekly Federal Register notice.

Sincerely,

/RA/

Shawn A. Williams, Senior Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-395

Enclosures:

1. Amendment No. 217 to NPF-12

2. Safety Evaluation cc: Listserv

DOMINION ENERGY SOUTH CAROLINA, INC.

SOUTH CAROLINA PUBLIC SERVICE AUTHORITY DOCKET NO. 50-395 VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 217 Renewed License No. NPF-12

1.

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

A.

The application for amendment to the Virgil C. Summer Nuclear Station, Unit No. 1 (the facility), Renewed Facility Operating License No. NPF-12 filed by Dominion Energy South Carolina, Inc. (the licensee), dated August 29, 2018, as supplemented by letters dated April 29, 2019, May 22, 2019, August 12, 2019, and October 9, 2019, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commissions 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 Commissions regulations as set forth in 10 CFR Chapter I; 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 Commissions regulations and all applicable requirements have been satisfied.

2.

Accordingly, the Renewed Facility Operating License No. NPF-12 is hereby amended as indicated in the attachment.

3.

This amendment is effective as of its date of issuance and shall be implemented within 30 days from the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to Renewed Facility Operating License Date of Issuance: March 6, 2020

VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 ATTACHMENT TO LICENSE AMENDMENT NO. 217 RENEWED FACILITY OPERATING LICENSE NO. NPF-12 DOCKET NO. 50-395 Replace the following pages of the Renewed Facility Operating License with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Remove License Pages Insert License Pages Page 7 Page 7 Page 10 Page 10 Renewed License No. NPF-12 Amendment No. 217

b.

In the event that one-third thickness semi-circular reference flaws cannot be detected and discriminated from inherent anomalies, the entire volume of the weld shall be examined during the inservice inspection.

c.

The reporting of the inservice inspection examination results shall be documented in a manner to define qualitatively whether, the weldment and the heat affected zone and adjacent base metal on both sides of the weld were examined by ultrasonic angle beam techniques.

(12)

Design Description - Control (Section 4.3.2, SER)

DESC is prohibited from using part-length rods during power operation.

(13)

Deleted (14)

Deleted (15)

Deleted (16)

Cable Tray Separation (Section 8.3.3, SSER 4)

Prior to startup after the first refueling outage, SCE&G* shall implement the modifications to the cable trays discussed in Section 8.3.3 of Supplement No. 4 to the Safety Evaluation Report or demonstrate to the NRC staff that faults induced in non-class 1E cable trays will not result in failure of cable in the adjacent Class 1E cable trays.

(17)

Alternate Shutdown System (Section 9.5.1, SSER 4)

Prior to startup after the first refueling outage, SCE&G* shall install a source range neutron flux monitor independent of the control complex as part of the alternate shutdown system.

(18)

Fire Protection Program Dominion Energy South Carolina, Inc. 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 license amendment request dated 11/15/11 (and supplements dated 1/26/12, 10/10/12, 2/1/13, 4/1/13, 10/14/13, 11/26/13, 1/9/14, 2/25/14, 5/2/14, 5/11/14, 8/14/14, 10/9/14, 12/11/14), and license amendment request dated 8/29/18 (and supplements dated 4/29/19, 5/22/19, 8/12/19, and 10/9/19) and as approved in safety evaluations dated 2/11/15 and 3/6/2020.

• On April 29, 2019, South Carolina Electric & Gas Company (SCE&G) changed its name to Dominion Energy South Carolina, Inc.

Renewed License No. NPF-12 Amendment No. 217

2.

Fire Protection Program Changes that Have No More than Minimal Risk Impact Prior NRC review and approval are not required for changes to the licensee's fire protection program that have been demonstrated to have no more than a minimal risk impact. The licensee may use its screening process as approved in the NRC safety evaluation dated February 11, 2015. The licensee shall ensure that fire protection defense-in-depth and safety margins are maintained when changes are made to the fire protection program.

c.

Transition License Conditions

1.

Before achieving full compliance with 10 CFR 50.48(c), as specified by c.2 and c.3 below, risk-informed changes to the licensee's fire protection program may not be made without prior NRC review and approval unless the change has been demonstrated to have no more than a minimal risk impact, as described in b.2 above.

2.

The licensee shall implement the modifications to its facility, as described in Attachment S, Table S-1, "Plant Modifications Committed," of SCE&G* letter RC-14-0196, dated December 11, 2014, as modified by Enclosure 1, Attachments 2 and 3, of the SCE&G* letter RC-18-0091, dated August 29, 2018. The licensee shall maintain appropriate compensatory measures in place until issuance of the safety evaluation.

3.

The licensee shall implement items listed in Attachment S, Table S-2, "Implementation Items," of SCE&G* letter RC-14-0196, dated December 11, 2014, to complete the transition to full compliance with 10 CFR 50.48(c) by March 31, 2016, as follows:

a.

Items 3, 6, 7, 8, 10, 13, 14, 17, 19, and 21 within 180 days of NRC approval.

b.

Items 1, 2, 4, 11, and 12 by December 31, 2015.

c.

Items 5, 15, 16, 18, 20, 22, and 23 by March 31, 2016.

(19)

Instrument and Control Vibration Tests for Emergency Diesel Engine Auxiliary Support Systems (Section 9.5.4, SER)

Prior to startup after the first refueling outage, SCE&G* shall either provide test results and results of analyses to the NRC staff for review

• On April 29, 2019, South Carolina Electric & Gas Company (SCE&G) changed its name to Dominion Energy South Carolina, Inc.

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 217 TO RENEWED FACILITY OPERATING LICENSE NO. NPF-12 DOMINION ENERGY SOUTH CAROLINA, INC.

VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 DOCKET NO. 50-395

1.0 INTRODUCTION

By letter dated August 29, 2018Property "Letter" (as page type) with input value "RC-18-0091, License Amendment Request - LAR-16-01490 National Fire Protection Association Standard 805 Program Revisions" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process. (Reference 1), as supplemented by letters dated April 29, 2019 (Reference 2), May 22, 2019 (Reference 3), August 12, 2019 (Reference 4), and October 9, 2019 (Reference 5), Dominion Energy South Carolina, Inc. (DESC, the licensee), submitted a license amendment request (LAR) to revise the Renewed Facility Operating License (RFOL)

No. NPF-12 for Virgil C. Summer Nuclear Station, Unit 1 (VCSNS, Summer).

The licensee requested to make changes to the licensing basis to Summers 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, Performance-Based Standard for Fire Protection for Light Water Reactor [LWR] Electric Generating Plants, (NFPA 805)), (Reference 6). The changes include plant modifications, performance based alternatives to NFPA 805, Section 3.3.4, Insulation Materials, and Section 3.3.5.1, Wiring above Suspended Ceilings, and approves clarification and editorial corrections to the NFPA 805 licensing basis.

Portions of the letters dated August 29, 2018, May 22, 2019, and October 9, 2019, contain security related information and, accordingly, have been withheld from public disclosure pursuant to 10 CFR 2.390.

The supplemental letters dated April 29, May 22, August 12, and October 9, 2019, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the U.S. Nuclear Regulatory Commission (NRC) staffs original proposed no significant hazards consideration determination as published in the Federal Register (FR) on December 4, 2018 (83 FR 62609).

2.0 REGULATORY EVALUATION

2.1 Background

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 Electric Generating Plants, 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 February 11, 2015 (Reference 7) (the NFPA 805 safety evaluation (SE)), the NRC staff approved the adoption of NFPA 805 for Summer, in Amendment 199.

2.2 Licensees Proposed Changes The licensee submitted numerous proposed changes that address different aspects of the NFPA 805 licensing basis.

2.2.1 General Changes to the Probabilistic Risk Assessment (PRA) Model The licensee proposed general changes to the PRA model that include changes to the Fire PRA model (FPRA) from approaches in accepted NUREGs and changes to reflect FPRA corrections and refinements.

See Section 3.1 of this SE. The SE section also includes a discussion regarding the internal events PRA (IEPRA) model and PRA modeling of the N-9000 Reactor Coolant Pump (RCP) seals with abeyance seal.

2.2.2 Plant Modifications to Table S-1, Plant Modifications Committed The licensee proposed to revise the NFPA 805 licensing basis plant modification scope of engineering change request (ECR) 50784, NFPA 805 Circuit Protection and ECR 50810, NFPA 805 Hazards Mitigation.

See Section 3.2 of this SE.

2.2.3 Performance-Based Alternatives to NFPA 805 Requirements The licensee requested NRC approval of two PB alternatives in lieu of meeting the requirements of NFPA 805 Section 3.3.4, Insulation Materials, and Section 3.3.5.1, Wiring above Suspended Ceilings.

See Section 3.3 of this SE.

2.2.4 Non-Cited Violations (NCVs) Related to the NFPA 805 Licensing Basis The licensee proposed to revise the NFPA 805 licensing basis to address two NCVs:

Fire Doors IB105A and IB105B, the subject of NCV 05000395/2016001-01 and Violation 05000395/2016007-01 (Reference 8).

RCP Lube Oil Collection System, the subject of Violation 05000395/2017002-01, NCV 05000395/2017002-02 (Reference 9), and NCV 5000395/2013003-03 (Reference 10).

See Section 3.4 of this SE.

2.2.5 Additional Clarification and Editorial Corrections to the NFPA 805 Licensing Basis As a result of an independent assessment of Summers compliance with the February 11, 2015, NFPA 805 SE, the licensee identified numerous statements in the SE that were inconsistent with actual plant conditions. The licensee proposed several clarification and editorial corrections to correct the NFPA 805 licensing basis.

See Section 3.5 of this SE.

2.2.6 RFOL No. NPF-12 Changes The licensee proposed to revise RFOL paragraph 2.C.(18), Fire Protection Program, to include reference to the August 29, 2018, LAR, supplemental letters dated April 29, 2019, May 22, 2019, August 12, 2019, and October 9, 2019, and this safety evaluation.

The licensee also requested to revise the second Transition License Condition in paragraph 2.C.(18).c.2. as follows (changes shown in bold):

The licensee shall implement the modifications to its facility, as described in Attachment S, Table S-1, "Plant Modifications Committed," of SCE&G* letter RC-14-0196, dated December 11, 2014, as modified by Enclosure 1, Attachments 2 and 3, of SCE&G letter RC-18-0091, dated August 29, 2018.

The licensee shall maintain appropriate compensatory measures in place until issuance of the safety evaluation.

See Section 3.6 of this SE.

2.3 Regulatory Requirements Appendix A to 10 CFR Part 50, General Design Criterion (GDC) 3, Fire protection, states:

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. Fire detection and fighting systems of appropriate capacity and capability shall be provided and designed to minimize the adverse effects of fires on structures, systems, and components important to safety. Firefighting systems shall be designed to assure that their rupture or inadvertent operation does not significantly impair the safety capability of these structures, systems, and components.

Section 50.48, Fire protection, of 10 CFR, provides the NRC requirements for nuclear power plant (NPP) fire protection. Section 50.48(a)(1) of 10 CFR requires that each holder of an operating license have a fire protection plan that satisfies GDC 3, Fire protection, of Appendix A to 10 CFR Part 50, General Design Criteria for Nuclear Power Plants.

Section 50.48(a)(1) of 10 CFR states, in part:

This fire protection plan must:

(i)

Describe the overall fire protection program for the facility; (ii)

Identify the various positions within the licensee's organization that are responsible for the program; (iii)

State the authorities that are delegated to each of these positions to implement those responsibilities; and (iv)

Outline the plans for fire protection, fire detection and suppression capability, and limitation of fire damage.

Section 50.48(a)(2) of 10 CFR states:

The plan must also describe specific features necessary to implement the program described in paragraph (a)(1) of this section such as (i)

Administrative controls and personnel requirements for fire prevention and manual fire suppression activities; (ii)

Automatic and manually operated fire detection and suppression systems; and (iii)

The means to limit fire damage to structures, systems, and components important to safety so that the capability to shut down the plant safely is ensured.

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 a 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 a RI/PB FPP based on the provisions of NFPA 805.

Section 50.48(c)(2)(vii), Performance-based methods, of 10 CFR states:

Notwithstanding the prohibition in Section 3.1 against the use of performance-based methods, the fire protection program elements and minimum design requirements of Chapter 3 may be subject to the performance-based methods permitted elsewhere in the standard. Licensees who wish to use performance-based methods for these fire protection program elements and minimum design requirements shall submit a request in the form of an application for license amendment under § 50.90. 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 performance-based approach; (A)

Satisfies the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release; (B)

Maintains safety margins; and (C)

Maintains fire protection defense-in-depth [DID] (fire prevention, fire detection, fire suppression, mitigation, and post-fire safe shutdown capability).

Section 50.48(c)(3)(i) of 10 CFR states:

A licensee may maintain a fire protection program that complies with NFPA 805 as an alternative to complying with paragraph (b) of this section

[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.

Section 50.48(c)(3)(ii) of 10 CFR states:

The licensee shall complete its implementation of the methodology in Chapter 2 of NFPA 805 (including all required evaluations and analyses) and, upon completion, modify the fire protection plan required by paragraph (a) of this section to reflect the licensees decision to comply with NFPA 805, before changing its fire protection program or nuclear power plant as permitted by NFPA 805.

Section 50.48(c)(4), Risk-informed or performance-based alternatives to compliance with NFPA 805, of 10 CFR states:

A licensee may submit a request to use risk-informed or performance-based alternatives to compliance with NFPA 805. The request must be in the form of an application for license amendment under § 50.90 of this chapter. The Director of the Office of Nuclear Reactor Regulation, or designee of the Director, may approve the application if the Director or designee determines that the proposed alternatives:

(i)

Satisfy the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release; (ii)

Maintain safety margins; and (iii)

Maintain fire protection defense-in-depth (fire prevention, fire detection, fire suppression, mitigation, and post-fire safe shutdown capability).

2.4 Applicable Codes, Standards, and Regulatory Guides Revision 3 of Regulatory Guide (RG) 1.174, An Approach for Using Probabilistic Risk Assessment in Risk Informed Decisions on Plant-Specific Changes to the Licensing Basis, (Reference 11), provides an acceptable approach for using risk information in support of proposed changes to the current licensing basis.

Revision 2 of RG 1.200, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities, (Reference 12), provides guidance to licensees for use in determining the technical adequacy of the base PRA used in an RI regulatory activity and endorses standards and industry peer review guidance. The RG provides guidance in four areas:

1.

A definition of a technically acceptable PRA;

2.

The NRCs position on PRA consensus standards and industry PRA peer review program documents;

3.

Demonstration that the baseline PRA (in total or specific pieces) used in regulatory applications is of sufficient technical adequacy; and

4.

Documentation to support a regulatory submittal.

Revision 1 of RG 1.205, Risk-Informed, Performance-Based Fire Protection for Existing Light Water Nuclear Power Plants, (Reference 13), 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. 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 (Reference 14); and provides exceptions to the NEI 04-02 guidance. If a conflict occurs between NEI 04-02 and RG 1.205, the regulatory positions in RG 1.205 govern.

NUREG/CR-6850, EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities, Volumes 1 and 2 and Supplement 1, (Reference 15), (Reference 16), (Reference 17),

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

NEI 04-02 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. NEI 04 02 incorporates guidance from RG 1.205 and approved Frequently Asked Questions (FAQs).

American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS)

RA-Sa-2009, Addenda to ASME/ANS RA-S-2008, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications (Reference 18),

provides guidance for PRAs used to support RI decisions for commercial LWR NPPs and prescribes a method for applying these requirements for specific applications. The standard gives guidance for a Level 1 PRA of internal and external hazards for all plant operating modes.

In addition, the standard provides guidance for a limited Level 2 PRA sufficient to evaluate large early release frequency (LERF). The only hazards explicitly excluded from the scope are accidents resulting from purposeful human-induced security threats (e.g., sabotage). The standard applies to PRAs used to support applications of RI decision making related to design, licensing, procurement, construction, operation, and maintenance.

2.5 NFPA 805 Fire Protection Requirements The 2001 edition of NFPA 805 specifies the minimum fire protection requirements for existing LWR 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 standard was developed in accordance with NFPA processes and consisted of a number of technical meetings and reviews of draft documents by committee and industry representatives. 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.

NFPA 805, Section 1.2, Defense-in-Depth, states:

Protecting the safety of the public, the environment, and plant personnel from a plant fire and its potential effect on safe reactor operations is paramount to this standard. The fire protection standard shall be based on the concept of defense-in-depth. Defense-in-depth shall be achieved when an adequate balance of each of the following elements1 is provided:

(1) Preventing fires from starting; (2) Rapidly detecting fires and controlling and extinguishing promptly those fires that do occur, thereby limiting fire damage; and (3) Providing an 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.

1 The elements of Defense-in-Depth are referred to as elements or echelons throughout this SE as both terms were used by the licensee.

NFPA 805, Section 1.3.1, Nuclear Safety Goal, states:

The nuclear safety goal is to provide reasonable assurance that a fire during any operational mode and plant configuration will not prevent the plant from achieving and maintaining the fuel in a safe and stable condition.

NFPA 805, Section 1.3.2, Radioactive Release Goal, states:

The radioactive release goal is to provide reasonable assurance that a fire will not result in a radiological release that adversely affects the public, plant personnel, or the environment.

NFPA 805, Section 1.4.1, Nuclear Safety Objectives, states:

In the event of a fire during any operational mode and plant configuration, the plant shall be as follows:

(1)

Reactivity Control. Capable of rapidly achieving and maintaining subcritical conditions.

(2)

Fuel Cooling. Capable of achieving and maintaining decay heat removal and inventory control functions.

(3)

Fission Product Boundary. Capable of preventing fuel clad damage so that the primary containment boundary is not challenged.

NFPA 805, Section 1.4.2, Radioactive Release Objective, states:

Either of the following objectives shall be met during all operational modes and plant configurations.

(1)

Containment integrity is capable of being maintained.

(2)

The source term is capable of being limited.

NFPA 805, Section 1.5.1, Nuclear Safety Performance Criteria, states:

Fire protection features shall be capable of providing reasonable assurance that, in the event of a fire, the plant is not placed in an unrecoverable condition. To demonstrate this, the following performance criteria shall be met:

(a)

Reactivity Control. Reactivity control shall be capable of inserting negative reactivity to achieve and maintain subcritical conditions.

Negative reactivity inserting shall occur rapidly enough such that fuel design limits are not exceeded.

(b)

Inventory and Pressure Control. With fuel in the reactor vessel, head on and tensioned, inventory and pressure control shall be capable of controlling coolant level such that sub-cooling is maintained for a PWR

[pressurized-water reactor] and shall be capable of maintaining or rapidly restoring reactor water level above top of active fuel for a BWR

[boiling-water reactor] such that fuel clad damage as a result of a fire is prevented.

(c)

Decay Heat Removal. Decay heat removal shall be capable of removing sufficient heat from the reactor core or spent fuel such that fuel is maintained in a safe and stable condition.

(d)

Vital Auxiliaries. Vital auxiliaries shall be capable of providing the necessary auxiliary support equipment and systems to assure that the systems required under (a), (b), (c), and (e) are capable of performing their required nuclear safety function.

(e)

Process Monitoring. Process monitoring shall be capable of providing the necessary indication to assure the criteria addressed in (a) through (d) have been achieved and are being maintained.

NFPA 805, Section 1.5.2, Radioactive Release Performance Criteria, states:

Radiation release to any unrestricted area due to the direct effects of fire suppression activities (but not involving fuel damage) shall be as low as reasonably achievable and shall not exceed applicable 10 CFR, Part 20, Limits.

2.5.1 Maintaining Defense-in-Depth and Safety Margins Section 4.2.4.2 of NFPA 805 requires that the use of fire risk evaluation for the performance-based approach shall consist of an integrated assessment of the acceptability of risk, defense-in-depth, and safety margins.

2.5.2 Defense-in-Depth As a supplement to the definition of DID provided in NFPA 805, Section 1.2, the NRC-endorsed guidance in NEI 04-02, Section 5.3.5.2, states, in part:

In general, the defense-in-depth 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.

2.5.3 Safety Margins Although not a part of the requirements of NFPA 805, and thus not required under 10 CFR 50.48(c), NFPA 805, 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 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.

3.0 TECHNICAL EVALUATION

3.1 General Changes to the PRA Model Changes in PRA models beyond those to directly model plant changes identified in the LAR have been incorporated into the risk results. These PRA general model changes consist of changes to the FPRA model from approaches in accepted NUREGs and changes to reflect FPRA corrections and refinements. The licensee indicated that it used accepted methods from its NFPA 805 LAR and additional approaches in NRC-accepted NUREGs to support these changes to the PRA model.

3.1.1 Proposed Changes to the FPRA from NUREGs 3.1.1.1 Licensees Proposed Changes The licensee utilized the guidance provided in several NUREGs beyond those utilized in the original NFPA 805 LAR (Reference 19). They are NUREG-2178, Refining and Characterizing Heat Release Rates from Electrical Enclosures During Fire (RACHELLE-FIRE), Volume 1: Peak Heat Release Rates and Effect of Obstructed Plume, (Reference 20), NUREG-2169, Nuclear Power Plant Fire Ignition Frequency and Non-Suppression Probability Estimation Using the Updated Fire Events Database, (Reference 21), and NUREG-2180, Determining the Effectiveness, Limitations, and Operator Response for Very Early Warning Fire Detection Systems in Nuclear Facilities (DELORES-VEWFIRE), (Reference 22).

Application of NUREG-2178 is associated with probability distributions for heat release rates (HRRs) in electrical cabinets and the treatment for obstructed fire plume configurations. This change consisted of applying the HRR probability distributions documented in NUREG-2178 to the electrical cabinets in several fire areas (i.e. Fire Areas CB06 and CB15). Walkdowns were conducted to perform visual examination of the electrical cabinet internals. As part of the walkdowns, the top of each cabinet to which the obstructed plume model was applied was inspected to determine the applicability for this model. The updated HRRs and obstructed plume models were incorporated into this change.

Application of NUREG-2169 is associated with the generic ignition frequencies and manual non-suppression probabilities. This change consisted of replacing the generic ignition frequencies documented in Chapter 10 of NUREG/CR-6850, Supplement 1, with the values available in NUREG-2169 and using the non-suppression probabilities from NUREG-2169. This adjustment addresses the FPRA in general.

Application of NUREG-2180 is associated with the treatment of incipient detection systems in Fire Areas CB06 and CB15. The change involved replacing the methodology described in NUREG/CR 6850, Supplement 1, Chapter 13, based upon FAQ 08-0046, Closure of National Fire Protection Association 805 Frequently Asked Question 08-0046: Incipient Fire Detection Systems, (Reference 23), with the approach described in NUREG-2180. Specifically, the update consisted of removing the credit for incipient detection calculated using FAQ 08-0046 from the scenarios in Fire Areas CB06 and CB15 where credit was applied previously and replacing it with applicable credit calculated using the guidance in NUREG-2180. The HRR probability distributions and obstructed plume models identified above in NUREG-2178 were implemented primarily to overcome the risk increase associated with the updated credit calculated for the incipient detection system from NUREG-2180.

3.1.1.2

NRC Staff Evaluation

The HRRs from NUREG-2178 and fire ignition frequencies and non-suppression probabilities from NUREG-2169 replaced certain respective HRRs and fire ignition frequencies and non-suppression probabilities from the original LAR. The approach to characterize the risk from incipient detection from the original NFPA 805 LAR was replaced by NUREG-2180. The licensee examined the cabinet internals and inspected the cabinet for determining the applicability of the obstructed plume model in NUREG-2178. Since NUREG-2178, NUREG-2169, and NUREG-2180 compose accepted approaches, the NRC staff finds that the licensees proposed use acceptable.

The licensee recalculated ignition frequencies for new plant ignition sources, which is a similar exercise to establishing frequencies at the outset for a NPP. Cables were rerouted, which is a traditional fire protection measure that affects the fire damage assessment for a given fire scenario. Detailed reviews of conduit locations were performed to provide greater precision of locations for fire scenarios and better estimates for fire damage. Since the licensee applied methods to perform state-of-practice PRA assessments similar to those from its original NFPA 805 LAR, the NRC staff finds that the licensee used accepted methods.

3.1.2 FPRA Model Corrections and Refinements 3.1.2.1 Licensees Proposed Changes The FPRA model corrections and refinements discussed in the LAR and the licensees supplement dated October 9, 2019, are:

Additional risk reduction activities included detailed FM [Fire Modeling], detailed circuit analysis, logic model refinements, expansion of credit for circuit failure mode probabilities using NUREG/CR-7150, Volume 2, Joint Assessment of Cable Damage and Quantification of Effects from Fire (JACQUE-FIRE): Final Report, (Reference 24), for risk significant circuits, and detailed fire human reliability analysis (HRA). As a part of this activity, additional circuit analysis was performed to ensure availability of power supplies to support RCP thermal barrier cooling.

Refinements in the main control room (MCR) abandonment model. Originally, the FPRA was quantified crediting MCR abandonment in all fire scenarios associated with the fire areas designated as alternate shutdown. The updated MCR abandonment model is symptom-based and, for the fire scenarios that lead to a loss of control (LOC) in the MCR, credits MCR abandonment based on fire impacts on plant safety functions. Specifically, MCR abandonment due to LOC is specified for fire scenarios that result in the loss of emergency feedwater consistent with the applicable post-fire shutdown procedure.

Operator action timelines and modeling associated with actions in the MCR to trip RCPs and local actions to trip RCPs manually have been refined using methods consistent with NUREG-1921 EPRI/NRC-RES Fire Human Reliability Analysis Guidelines - Final Report, (Reference 25).

Refinements in modeling of the multiple spurious operation (MSO) scenarios based upon completion of required NFPA 805 modifications. Refinements included detailed circuit analysis and logic corrections in the model. Scenario-specific credit for local RCP trip to avoid RCP seal loss of coolant accident (LOCA) was introduced into the model as a recovery action (RA). Procedure changes and modeling changes were made to include additional credit for RCP trip from the MCR and locally, as required.

Updates to the HRA dependency analysis to comprehensively identify human failure event (HFE) combinations and apply joint human error probabilities (HEPs) to all combinations found using the HRA Calculator with HEPs artificially increased to prevent truncation. This is not a change to the dependency approach, but only the capturing of more or different combinations.

An abnormal operating procedures (AOP) was revised to move RCP seal monitoring to an earlier step. This change to the PRA was evaluated with methods consistent with NUREG-1921.

Scenario-specific credit was taken for use of disconnect switches to prevent/mitigate spurious actuations. Procedure changes were implemented to allow credit for use of disconnect switches in select fire areas. This update reflects incorporating procedure changes into the PRA model using the same HRA methods.

Refinements in the modeling of breaker coordination. Additional circuit analysis was performed to explicitly model selected breakers in the FPRA. The modeling of these breakers, including the circuit analysis and cable routing necessary to incorporate them as targets in the model was conducted using the same approved methods as had been used in the FPRA during the NFPA 805 transition process.

Screening of multi compartment scenarios using detailed FM techniques, used elsewhere in the original LAR analysis, for determining hot gas layer (HGL) temperatures in the exposed or exposing compartments.

Correction of the fire initiator fault tree configuration, which was preventing the quantification of the risk contribution of fire scenarios associated with the transient initiators. To address this, the fire initiator was inserted into the FPRA model logic to allow the affected event sequences to propagate through the model. This correction did not require new accident sequence logic.

Some of the physical plant modifications required as part of the NFPA 805 transition process were not properly accounted for in some fire scenarios.

Updates were made to reflect the proper credit in the fire scenarios, including verification and updates in protection provided by electrical raceway fire barrier systems (ERFBS) and fire-rated cable, as well as model updates and circuit analysis to ensure proper credit in the model for offsite power availability.

Fire impacts to some of the containment isolation paths in the model were previously not captured. It should be noted that the criteria for what is considered a containment bypass remained unchanged, however, updates necessary to ensure fire impacts of these valves, including logic refinements with detailed circuit analysis were implemented.

Selected fire scenarios were updated to reflect the presence of non-cable secondary combustibles. These secondary combustibles were incorporated in the FPRA by increasing the HRR profile previously used in the analysis to reflect the fire intensity of these combustibles. The addition of the secondary combustibles was required for a limited number of fire zones and is primarily associated with combustible insulation and High-Density Polyethylene (HDPE) piping.

Detailed reviews of conduit locations were performed to provide greater precision of their locations for fire scenarios.

Other PRA changes were made to account for additional ignition sources in the plant, and to account for cable rerouting.

3.1.2.2

NRC Staff Evaluation

Several of the model changes refer to performing circuit analysis, and in particular analyzing MSOs, and employed NUREG/CR-7150, an NRC approved NUREG for performing such activities. Hardware such as disconnect switches to mitigate/prevent spurious operations have been analyzed, and thus the impact of spurious operations adjusted. Additional HRA was performed, including refinements to the dependency analysis, using methods described in the original NFPA 805 LAR. Operator action timelines and modeling associated with actions in the MCR to trip RCPs and local actions to trip RCPs manually have been refined using methods consistent with NUREG-1921. An AOP was revised to move RCP seal monitoring to an earlier step. This change to the PRA was evaluated with methods consistent with NUREG-1921.

Breaker coordination has also been evaluated using accepted methods from the original NFPA 805 LAR. Detailed FM used elsewhere in the original NFPA 805 LAR has been used to refine multicompartment fire analysis. Since existing methods from the original NFPA 805 LAR or NRC approved NUREGs have been applied in the changes to the PRA model, the NRC staff finds that the licensee used accepted methods.

Additional corrections and refinements were made to the FPRA model corresponding to the fire-initiated transient initiating event, to scenarios incorporating ERFBS and fire rated cable, to fire damage of containment isolation paths, and to secondary combustibles in the fire scenarios.

Revisions have been made to ensure that the sequences associated with transient initiators properly propagate through the PRA model. Fire scenarios were corrected to reflect fire rated cables and ERFBS properly. The licensee indicated that assessing fire damaged components, such as those of the containment isolation paths, and performing the associated circuit analysis are done with methods from the original NFPA 805 LAR. Since these changes to the PRA model have been implemented with methods from the original NFPA 805 LAR, the NRC staff finds that the licensee used accepted methods.

The NRC staff issued PRA request for additional information (RAI) 01 (Reference 26), regarding the changes to the MCR abandonment modeling and requested that the licensee describe whether the changes to the abandonment modeling exceeded that described in the original NFPA 805 LAR, and whether the refinement to the PRA model is consistent with plant procedures. In its response to PRA RAI 01, dated April 29, 2019, the licensee indicated that it refined the conditions for abandonment due to LOC contained in their procedure for alternate shutdown. The licensee indicated that refined PRA logic was introduced in the model as a result of HRA operator reviews and procedure reviews with respect to the conditions that lead to MCR abandonment. The licensee indicated that it made procedure changes in conjunction with the corresponding FPRA model changes. The licensee noted that MCR abandonment HRA was performed using the detailed HRA methods and practices cited in NUREG-1921, and that additional refinements were introduced into the MCR abandonment logic with respect to proper treatment of equipment required for remote shutdown, including introducing logic in the model to preclude successful shutdown for the Control Room Evacuation Panel under certain conditions.

The licensee indicated that with respect to MCR abandonment due to loss of habitability (LOH),

it adjusted the conditions leading to MCR abandonment due to habitability for NUREG-2178.

The licensee indicated that probability of abandonment continues to meet the criteria for control room evacuation described in NUREG/CR-6850 and the PRA model for MCR abandonment due to LOH are consistent with plant procedures. The licensee indicated that the remainder of this analysis for MCR abandonment due to LOH is unchanged from the original NFPA 805 LAR, thus, the MCR abandonment model changes rely on accepted NUREGs and existing methods from the original NFPA 805 LAR. The licensee indicated that abandonment from LOC PRA logic was also improved from operator interviews with respect to conditions leading to abandonment, and with respect to the conditions under which abandonment from LOC will be unsuccessful, and that the PRA model for MCR abandonment for both LOH and LOC is consistent with plant procedures. The NRC staff finds the improvements and refinements to the methods used to model MCR abandonment acceptable.

The NRC staff issued PRA RAI 02 on March 13, 2019, regarding the increase in HRRs to account for secondary combustibles of insulation and HDPE piping and requested that the licensee summarize the approach used to increase the HRRs and discuss whether it was used previously to support the original NFPA 805 LAR or another NPPs NFPA 805 amendment. In its response to PRA RAI 02 dated April 29, 2019, the licensee indicated that the approach it used for increasing the HRRs is similar to the approach used in its FPRA for cable trays that are considered secondary combustibles. The licensee provided its step-based approach for analyzing the potential impact of the non-cable secondary combustibles to existing fire scenarios:

Step 1: Determine the ignition criteria (heat flux and temperature) for each noncable secondary combustible.

Step 2: Determine the zone of influence (ZOI) for a transient fire using the same models as NUREG-1805, Supplement 1, Fire Dynamics Tools (FDTs) Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program, (Reference 27), FDTs for plume temperature (Chapter 9) and heat flux point source model (Chapter 5) based on the ignition criteria.

Step 3: Determine HRR by multiplying the HRR per unit area (HRRPUA) for each combustible by Acomb, the area of the impacted combustible, using values of HRRPUA from fire industry journals and handbooks.

Step 4: Identify ignition sources with non-cable combustibles located within the calculated ZOI distances in fire zones with detailed FM.

The licensee indicated that the impacts due to the presence of non-cable combustibles, are included in the FPRA model from 2018, and are reflected in the quantification results presented in the LAR. The NRC staff finds the method the licensee used to increase the HRRs to account for secondary combustibles of insulation and HDPE piping acceptable because it is consistent with the guidance established in NUREG-1805, and because the impacts of the secondary combustibles are included in the current FPRA model and are reflected in the quantification results included in the LAR.

3.1.3 IEPRA 3.1.3.1 Licensees Proposed Changes In the LAR dated August 29, 2018, Attachment 1, as supplemented by the licensees responses to RAIs 03 and 04 dated May 22, 2019, and the licensees response to follow-up RAI 03 dated October 9, 2019, the licensee described the refinements to the IEPRA since the issuance of Amendment No. 199, associated with the transition to a RI/PB FPP in accordance with 10 CFR 50.48(c).

The IEPRA received a full-scope peer review in June 2016 against the applicable high-level requirements and supporting requirements of American Society of Mechanical Engineers/American Nuclear Society (ASME/ANS), Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications, ASME/ANS RA-Sa-2009, as endorsed by RG 1.200, Revision 2. The PRA peer review resulted in a number of facts and observations (F&Os). In LAR Attachment 8, as supplemented by the licensees response to RAI 05 dated May 22, 2019, the licensee provided the finding-level F&Os that remain open for the IEPRA and the disposition of these F&Os. Each F&O was dispositioned by either providing a description of how the F&O was resolved or providing an assessment of the impact of the F&O resolution on the LAR results.

3.1.3.2

NRC Staff Evaluation

The NRC staff evaluated each F&O and the licensees disposition to determine whether the F&O had any significant impact on the application. The NRC staff finds the finding-level F&Os that remain open were assessed properly and dispositioned to support the application. Based on the response to RAIs 03, 04, and follow-up RAI 03, the changes to the IEPRA since the full-scope peer review in 2016 are PRA maintenance as defined in ASME/ANS Ra-Sa-2009 and endorsed by, with clarifications and qualifications, RG 1.200, Revision 2. Therefore, in accordance with the regulatory position in RG 1.200, Revision 2, no additional peer reviews were required for the IEPRA.

3.1.4 PRA Modeling of the N-9000 RCP seals with Abeyance Seal 3.1.4.1 Licensees Proposal Section 2.4.3.3 of NFPA 805 states that the PRA approach, methods, and data shall be acceptable to the NRC. The LAR, as supplemented by letter dated May 22, 2019, described the PRA modeling of the N-9000 RCP seals with abeyance seal installed at Summer. The NRC staff identified the following issues with the licensees modeling of these seals in the PRA used to support the LAR:

The PRA had credited the abeyance seal using a method not approved by NRC. An NRC-accepted abeyance seal model is not available for modeling these seals.

The PRA credited a 60-minute system time window for operator action to trip RCPs without seal cooling. However, this time window is not consistent with that used in the RCP seal model accepted by NRC in the safety evaluation associated with Amendment No. 199, which is based on the RCP seal failure model and associated failure probabilities used in WCAP-16175-A, "Model for Failure of RCP Seals Given Loss of Seal Cooling in CE NSSS Plants (Reference 28). WCAP-16175-A indicates that the N-9000 RCP seals have been designed to survive 30 minutes of continued RCP operation without RCP seal cooling. Also, the response to RAI 1.15.1 documented in WCAP-16175-A states, [a]s data for RCP seal operation without seal cooling for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> is not available, this event will be redefined to require tripping the RCP within 20 minutes.

In response to PRA RAI 03 dated May 22, 2019, the licensee removed credit for the abeyance seals from the PRA because an NRC-accepted abeyance seal model is not available. In response to follow-up PRA RAI 03 dated October 9, 2019, the licensee clarified that the PRAs, excluding the FPRA, credited a 20-minute system time window for operator action to trip RCPs without seal cooling, which is consistent with that used in the RCP seal model accepted by NRC in the safety evaluation associated with Amendment No. 199. For the FPRA, the system time window for operator action to trip RCPs without seal cooling was redefined from 60 minutes to 20 minutes, consistent with the FPRA RCP seal failure model accepted in the safety evaluation associated with Amendment No. 199.

3.1.4.2

NRC Staff Evaluation

With respect to modeling the N-9000 RCP seals with abeyance seal, the NRC staff determined that the RCP seal model used in this application is acceptable because the modeling of these seals is consistent with the required tripping of RCPs within 20 minutes accepted by the NRC in the NFPA 805 SE.

3.

1.5 NRC Staff Conclusion

Regarding General Changes to the PRA Model The NRC staff concludes that the above general changes to the PRA model, to the extent they are discussed in the LAR, relied upon NRC-accepted methods. The LAR indicated that those accepted methods were either used in the original NFPA 805 LAR or were taken from NUREGs beyond those used in the original NFPA 805 LAR. Thus, the NRC staff finds that general changes to the PRA model and FPRA model corrections and refinements, as provided in the LAR and supplements are acceptable for use in the integrated PRA analysis.

3.2 Plant Modifications to Table S-1, Plant Modifications Committed Summers original NFPA 805 LAR, dated November 15, 2011, contained a list of committed plant modifications within Table S-1 and a list of Variances from Deterministic Requirements (VFDR). In letter dated October 10, 2012Property "Letter" (as page type) with input value "RC-12-0142, License Amendment Request - LAR-06-00055, License Amendment Request to Adopt NFPA 805, Response to Request for Additional Information" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., the licensee clarified the scope of two engineering change requests (ECRs), ECR 50784, NFPA 805 Circuit Protection, and ECR 50810, NFPA 805 Hazards Mitigation.

During the transition period to fully implement NFPA 805, the licensee identified that some aspects of ECR 50784 and ECR 50810 were descoped and identified additional modifications that were not implemented. Specifically, the licensee identified that the completed scopes of ECR 50784 and ECR 50810 is not consistent with the description of what was submitted and approved in the NFPA 805 SE dated February 11, 2015. The licensee inappropriately used a PB fire risk evaluation to descope modifications without obtaining prior NRC approval.

Therefore, in this LAR, the licensee is requesting NRC approval to revise the scope of ECR 50784 and ECR 50810 to allow the VFDRs impacted by the modification scope change to be resolved using an updated PB fire risk evaluation methodology approved by the NRC.

In modification ECR 50784, the licensee proposed to provide protection of tubing/circuits from the effects of fire. The licensee stated that protection in the form of 3-hour to 1-hour fire rating is being provided for select circuits identified through the nuclear safety capability assessment (NSCA).

In modification ECR 50810, the licensee proposed to provide mitigation strategies to address fire initiators or limit fire propagation. The licensee stated that a sensitivity study for the FPRA showed that this modification is highly important.

The plant modifications were incorporated into Fire Areas AB01, CB01, IB17, and IB25. NRC staffs evaluation of the modifications to each of the Fire Areas is provided below.

3.2.1 Licensees Fire Risk Evaluations (FRE) of the Plant Modifications In the August 29, 2018, LAR, Enclosure 1, Attachment 5, the licensee stated that it incorporated the physical plant modifications and procedure changes completed during the NFPA 805 implementation phase of the transition process in the FPRA model as required by Implementation Item 22 of the original NFPA 805 LAR, Table S-2, dated December 11, 2014.

The licensee stated that the PRA model also accounted for changes to the modification scopes

[ECR 50784 and ECR 50810] that are being addressed in this LAR.

The licensee stated that the FREs were updated to reflect the as-built as-operated plant and that the results show the change in risk due to the NFPA 805 transition meets the acceptance guidelines of RG 1.205.

In its letter dated October 9, 2019, the licensee calculated the plant total change (delta) in risk from the post-transition plant to the compliant plant. The results show a negative delta, thus a decrease in plant total fire risk in core damage frequency (CDF) and large early release frequency (LERF). The licensee stated that RG 1.174, Section 2.4, provides that if the application shows a decrease in CDF and LERF, the guidelines of RG 1.174 are met.

3.2.2 Licensees Safety Margin Evaluation of the Plant Modifications The licensee concluded that the plant modifications do not affect the safety margin evaluation for the Fire Areas AB01, CB01, IB17, and IB25, completed for the original NFPA 805 LAR, which is based on NEI 04-02 and RG 1.205. The licensee stated that maintenance of safety margin for the analyses supporting the FRE of the affected fire areas is ensured as follows:

FM: FM performed in support of this FRE was done utilizing codes and standards developed by industry and NRC staff to provide realistic yet conservative results. Specifically, the HRRs used in the transition analysis were based on NUREG/CR-6850, Task 8, Scoping FM. These HRRs are conservative and were used to screen out fixed ignition sources that do not pose a threat to the targets located in the affected fire areas.

Plant System Performance: Plant system performance parameters were not modified as a result of the FRE in the affected fire areas.

PRA Logic Model: The bases for the application of the codes and standards supporting the FPRA were not altered in support of the FRE in the affected fire areas.

Success Path Confirmation: In accordance with the requirements of 10 CFR 50.48(c)(iii), the FPRA results, including cut sets for the scenarios of concern, were reviewed and it was verified that the results presented above do not rely solely on feed and bleed as the fire-protected safe shutdown path for maintaining reactor coolant inventory, pressure control, and decay heat removal capability in case of a fire in the affected fire areas.

3.2.3 Fire Area AB01 Modifications DROID2-AB01.01, 02, 03, 04, 06, 09 Area Cooling for Charging Pump A and B Rooms The licensee stated that cables required for operation of area cooling for the Charging Pump A

& B rooms are protected by 1-hour rated ERFBS, and that full automatic suppression is required for the 1-hour rated fire barrier to achieve deterministic compliance. The licensee stated that the change in modification scope (no longer expanding the automatic suppression to the entire fire zone) requires this DROID to be resolved with a PB FRE, since ECR 50810 did not modify the plant to achieve full automatic suppression coverage. The licensee stated that automatic fire suppression is no longer credited in the NSCA for Fire Zone AB01.09.

DROID-AB01.01, 02, 03, 04, 06, 09 Charging Pumps A & B The licensee stated that cables required for operation of Charging Pumps A & B are protected by 1-hour rated ERFBS, and that full automatic suppression is required for the 1-hour rated fire barrier to achieve deterministic compliance. The licensee noted that the change in modification scope (no longer expanding the automatic suppression to the entire fire zone) requires this DROID to be resolved with a PB FRE, since ECR 50810 did not modify the plant to achieve full automatic suppression coverage. The licensee stated that automatic fire suppression is no longer credited in the NSCA for Fire Zone AB01.09.

2 VFDRs are identified as Deterministic Requirement Open Item Description (DROID) at Summer.

DROID-AB01.01, 02, 03, 04, 06, 09 Charging Pumps A & B Mini-Flow Isolation The licensee stated that ECR 50784 modified circuit CS C 82B to replace portions of the circuit with a 3-hour fire rated cable, and that the new fire rated cable terminates at splice boxes located in Fire Zones AB01.04 and AB01.09. The licensee stated that the original scope of ECR 50784 prescribed the installation of an ERFBS to protect the splice box and the remainder of the non-fire rated circuit in Fire Zones AB01.04 and AB01.09. The licensee stated that the ECR scope has been modified to remove the scope of work to protect the splice boxes and non-fire rated circuits and that this change in modification scope requires this DROID to be resolved with a PB FRE, since ECR 50784 did not fully result in complete 3-hour fire rated barrier protection for cables associated with the Charging Pump Mini-Flow Isolation Valves. The licensee stated that the portion of the circuit that is protected with a 1-hour ERFBS is not deterministically compliant, since the fire zone does not contain full automatic suppression coverage.

AB01.21 - No DROID Impacted The licensee stated that both the FPRA and NSCA models do not credit automatic fire suppression in Fire Zones AB01.21.01 and AB01.21.02, and that there is no DROID associated with automatic fire suppression in Fire Zones AB01.21.01 and AB01.21.02, therefore, the change in scope to ECR 50810 to not include enhancements to the automatic suppression system in AB01.21.01 and AB01.21.02 has no impact on the NFPA 805 program, since the system is not needed to support deterministic compliance, for risk reduction, or to maintain sufficient DID.

3.2.3.1 Licensees Defense-in-Depth Evaluation for Fire Area AB01 The licensee stated that the DID evaluation for Fire Area AB01 has been updated in the PB fire risk analysis to reflect the as-built configuration, which includes the adjustments in modification scope for Fire Area AB01. The licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA to ensure adequate DID is maintained. In particular, for this fire area, the LAR indicates that automatic suppression was not expanded to the full fire zone in some zones in the fire area and in some other zones, 3-hour fire barrier protection was not installed. For the cases where the existing automatic suppression system was not expanded to the full zone, the NRC staff found that the available DID fire protection features discussed in LAR Attachment C, NEI 04-02 Table B-3 Fire Area Transition include other means of suppression to supplement the partial automatic suppression system.

The licensee stated that echelons 1 and 2 are captured in the frequencies of the fire scenarios applicable to the fire area. The licensee stated that automatic suppression systems exist in several of the fire zones of the fire area, however, they were not credited in the FPRA. The licensee noted that installed detection systems were credited in several fire zones of the fire area to support manual suppression, and that in other fire zones and sub-zones, fire detection and manual suppression were not credited. The licensee stated that there is no high-frequency fire (expected to occur more than once over a 10 year span) in this fire area, and concluded that an adequate balance is maintained between echelons 1 and 2. The licensee stated that echelon 3 is captured via the average conditional core damage probability (CCDP) in the fire area. The licensee stated that the conditional LERF is not considered for this echelon because it is less than the CCDP, and as such the CCDP is in itself a sufficiently representative metric.

The licensee stated that a fire scenario can be considered of high consequence if its frequency is more than 1E-06/yr and its CCDP is more than 0.1, and that there are no such high consequence scenarios in the fire area, thus, the balance of echelon 3 with the other echelons is maintained. The licensee concluded that the defense-in-depth in this fire area is appropriate, given the suitable balance of its three echelons, and concludes that no improvements appear necessary.

3.2.3.2 NRC Staff Evaluation of Modifications to Fire Area AB01 The NRC staff reviewed the information provided by the licensee in the LAR including discussions of the impact of the proposed changes on risk, DID, and safety margins, as required by NFPA 805, Section 4.2.4.2.

In regard to DID, the licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA, to ensure adequate DID is maintained for Fire Area AB01. In particular, the NRC staff determined that the lack of a 3-hour barrier in some zones of a fire area potentially affects echelon 3. The licensee retained its separate risk criteria for echelons 1, 2, and 3 accepted for the NFPA 805 transition, which need to be met to achieve a balance among DID echelons. For example, with respect to echelon 3, the licensee established risk criteria for a high consequence fire scenario, whereby the frequency of the scenario needs to be more than 1E-06/yr and the CCDP more than 0.1 for the scenario to be high consequence and for the DID echelon to not be met. In other zones of the fire area, the automatic suppression system was not expanded to the full zone. The licensee indicated those additional risk criteria for the DID echelons are met for the fire scenarios in this fire area. The NRC staff determined that the proposed changes do not create an imbalance between any of the DID echelons. Not completing the modifications has no impact on preventing fires from starting, maintains adequate DID for detecting or extinguishing fires, and continues to provide an adequate level of fire protection so that a fire will not prevent essential safety functions from being performed. The NRC staff based this decision on the available DID fire protection features described in the updated Attachment C, NEI 04-02 Table B-3 Fire Area Transition, for the affected fire area, and the qualitative analysis supported by the separate risk criteria for high frequency and high consequence fire scenarios established for the DID echelons. Because adequate DID exists for the affected fire area, the NRC staff concludes that DID is maintained.

In regard to safety margins, the NRC staff confirmed that the proposed changes continue to maintain sufficient safety margins because 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.

In regard to PRA methods, the NRC staff finds that the specific PRA manipulation to remove credit for the expansion of the automatic suppression system and to consequently damage the unprotected equipment is within the state-of-practice in PRA. Also, the licensee indicated that the change to the PRA model for this descoped modification is based on methods from its original NFPA 805 LAR. Therefore, the NRC staff finds this PRA change to be acceptable.

3.2.4 Fire Area CB01 Modifications DROID-CB01 Source Range Flux Monitors The licensee stated that the NSCA model requires at least one source range flux detector to be available for deterministic compliance, while the FPRA model does not credit these components for success, and that the original scope consisted of protecting the associated conduits and junction boxes for cable NI A 198D with an ERFBS to protect INI0032. The licensee stated that the final scope of ECR 50784 did not include a ERFBS for cable NI A 198D, and that this DROID is now resolved with a PB FRE per NFPA 805 4.2.4.2 Use of Fire Risk Evaluation.

DROID-CB01 Spurious Containment Isolation Phase A Signal The licensee stated that the NSCA report identifies a concern where fire damage could simulate a manual initiation of a Containment Isolation Phase A Signal, and that the FPRA model also considers this failure. The licensee stated that the original scope of ECR 50784 prescribed ERFBS to be placed on the cable trays which contained cable SG D 14B, however, the final scope of ECR 50784 did not include a ERFBS for cable SG D 14B, and that this DROID is now resolved with a PB FRE per NFPA 805 4.2.4.2 Use of Fire Risk Evaluation.

3.2.4.1 Licensees Defense-in-Depth Evaluation for Fire Area CB01 The licensee stated that the DID evaluation for Fire Area CB01 has been updated in the PB fire risk analysis to reflect the as-built configuration which includes the adjustments in modification scope for Fire Area CB01. The licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA to ensure adequate DID is maintained. In particular, for this fire area, the LAR indicates that ERFBS were not installed to protect certain cables.

The licensee stated that echelons 1 and 2 are captured in the frequencies of the fire scenarios applicable to the fire area. The licensee stated that automatic suppression systems exist in the fire zones of the fire area and that the automatic suppression system in CB01.02 only is credited in the FPRA. The licensee stated that installed detection was credited in CB01.01 and CB01.02. The licensee noted that there is no high-frequency fire in this fire area, and concluded that an adequate balance is maintained between echelons 1 and 2. The licensee stated that echelon 3 is captured via the average CCDP in the fire area. The licensee stated that the conditional LERF is not considered for this echelon because it is less than the CCDP, and as such the CCDP is in itself a sufficiently representative metric. The licensee stated that a fire scenario can be considered of high consequence if its frequency is more than 1E-06/yr and its CCDP is more than 0.1, and that there are no such high consequence scenarios in the fire area, thus, the balance of echelon 3 with the other echelons is maintained. The licensee concluded that the DID in this fire area is appropriate, given the suitable balance of its three echelons, and that no improvements appear necessary.

3.2.4.2 NRC Staff Evaluation of Modifications to Fire Area CB01 The NRC staff reviewed the information provided by the licensee in the LAR including discussions of the impact of the proposed changes on risk, DID, and safety margins as required by NFPA 805, Section 4.2.4.2.

In regard to DID, the licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA, to ensure adequate DID is maintained for Fire Area CB01. In particular, not installing the ERFBS to protect certain cables potentially affects echelon 3. The licensee retained its separate risk criteria for echelons 1, 2, and 3 accepted for the NFPA 805 transition which need to be met to achieve a balance among DID echelons. For example, with respect to echelon 3, the licensee established risk criteria for a high consequence fire scenario, whereby the frequency of the scenario needs to be more than 1E-06/yr and the CCDP more than 0.1 for the scenario to be high consequence and for the DID echelon to not be met. The licensee indicated those additional risk criteria for the DID echelons are met for the fire scenarios in this fire area, and from this perspective a balance amongst DID echelons continues to be achieved.

In further regard to DID, the NRC staff determined that the proposed changes have no impact on preventing fires from starting, or detecting or extinguishing fires, and continues to provide an adequate level of fire protection so that a fire will not prevent essential safety functions from being performed. Not installing a fire barrier has no impact on fire ignition, or detection or suppression of a fire. The NRC staff based this decision for echelon 3 upon the qualitative analysis supported by the separate risk criteria for high frequency and high consequence fire scenarios established for the DID echelons. Because adequate DID exists for the affected fire area, the NRC staff concludes that DID is maintained.

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

In regard to PRA methods, the NRC staff finds that the specific PRA manipulation to remove credit for an electrical raceway barrier system and to consequently damage the unprotected equipment is within the state-of-practice in PRA. Also, the licensee indicated that the change to the PRA model for this descoped modification is based on methods from its original NFPA 805 LAR. Therefore, the NRC staff finds this PRA change to be acceptable.

3.2.5 Fire Area IB17 Modifications DROID-IB17 XSW1DA Failure The licensee stated that the NSCA and FPRA models are impacted by cables ES M 83X and ES M 94X routed through Fire Area IB17 which, if fire damaged, could cause a failure to obtain power from 7.2kV Switchgear XSW1DA. The licensee stated that these cables were not modified by ECR 50784 or ECR 50800, so the DROID is now resolved with a PB FRE per NFPA 805 4.2.4.2, Use of Fire Risk Evaluation.

3.2.5.1 Licensees Defense-in-Depth Evaluation of Fire Area IB17 The licensee stated that the DID evaluation for Fire Area IB17 has been updated in the PB fire risk analysis to reflect the as-built configuration which includes the adjustments in modification scope for Fire Area IB17. The licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA to ensure adequate DID is maintained. In particular, for this fire area, the LAR indicates that separation to prevent a failure to obtain power from specific 7.2kV Switchgear is not achieved.

The licensee stated that echelons 1 and 2 are captured in the frequencies of the fire scenarios applicable to the fire area. The licensee stated that no automatic suppression systems exist in the fire area and that manual suppression was credited and incorporated in the fire scenario frequencies via a probability of non-suppression. The licensee noted that there is no high-frequency fire in this fire area, and concluded that an adequate balance is maintained between echelons 1 and 2. The licensee stated that echelon 3 is captured via the average CCDP in the fire area. The licensee stated that the conditional LERF is not considered for this echelon because it is less than the CCDP, and as such the CCDP is in itself a sufficiently representative metric. The licensee stated that a fire scenario can be considered of high consequence if its frequency is more than 1E-06/yr and its CCDP is more than 0.1, and that there are no such high consequence scenarios in the fire area, thus, the balance of echelon 3 with the other echelons is maintained. The licensee concluded that the DID in this fire area is appropriate, given the suitable balance of its three echelons and that no improvements appear necessary.

3.2.5.2 NRC Staff Evaluation of Modifications to Fire Area IB17 The NRC staff reviewed the information provided by the licensee in the LAR including discussions of the impact of the proposed changes on risk, DID, and safety margins as required by NFPA 805, Section 4.2.4.2.

In regard to DID, the licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA, to ensure adequate DID is maintained for Fire Area IB17. In particular, the LAR indicates that separation to prevent a failure to obtain power from specific 7.2kV Switchgear is not achieved, which potentially affects echelon 3. The licensee retained its separate risk criteria for echelons 1, 2, and 3 accepted for the NFPA 805 transition which need to be met to achieve a balance among DID echelons. For example, with respect to echelon 3, the licensee established risk criteria for a high consequence fire scenario, whereby the frequency of the scenario needs to more than 1E-06/yr and the CCDP more than 0.1 for the scenario to be high consequence and for the DID echelon to not be met. The licensee indicated those additional risk criteria for the DID echelons are met for the fire scenarios in this fire area, and from this perspective a balance amongst DID echelons continues to be achieved.

In further regard to DID, the NRC staff determined that the proposed changes do not create an imbalance between any of the DID echelons. Not providing fire-related separation to prevent fire damage with respect to providing power from specific 7.2kV Switchgear has no impact on preventing fires from starting or on detecting or extinguishing fires. The plant continues to provide an adequate level of fire protection so that a fire will not prevent essential safety functions from being performed. The NRC staff based this on the qualitative analysis supported by the separate risk criteria for high frequency and high consequence fire scenarios established for the DID echelons. Because adequate DID exists for the affected fire area, the NRC staff concludes that DID is maintained.

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

In regard to PRA methods, the NRC staff finds that the specific PRA manipulation to not credit separation and as a result to have power from specific 7.2kV Switchgear unavailable for the selected scenarios is within the state-of-practice of FPRA. Also, the licensee indicated that the change to the PRA model for this descoped modification is based on methods from its original NFPA 805 LAR. Therefore, the NRC staff finds this PRA change to be acceptable.

3.2.6 Fire Area IB25 Modifications DROID-IB25.04 Loss of Charging Pump Suction from VCT The licensee stated that two cables associated with valve LCV0115E are routed in IB25.04 which impact both the NSCA and the FPRA models, and that cable CS C 302B was partially replaced with a 3-hour fire rated cable by the same modification, however, the splice box where the new fire rated cable for CS C 302B terminates in IB25.04 was not protected as originally prescribed by ECR 50784. The licensee stated that the DROID is now resolved with a PB FRE per NFPA 805 4.2.4.2, Use of Fire Risk Evaluation.

DROID-IB25.04 Loss of Charging Pump Minimum Flow Path The licensee stated that the NSCA and FPRA models are both impacted by a potential fire-induced spurious closure of the Charging Pump Mini-Flow Valves in Fire Zone IB25.04, and that the DROID identifies fire damage potentially causing spurious closures of the A and C Charging Pump Mini-Flow Valves. The licensee stated that ECR 50784 prescribed for cable CS C 72B to be partially replaced with a 3-hour fire rated cable, with the terminating junction boxes and remaining cable in the affected fire zones protected with ERFBS, however, the junction box and remaining cable in Fire Zone IB25.04 were not protected, therefore, the DROID is now resolved with a PB FRE per NFPA 805 4.2.4.2, Use of Fire Risk Evaluation.

DROID-IB25.06, 07 XSW1DB Failure The licensee stated that the NSCA and FPRA models are both impacted by a possible fire-induced spurious closure of the alternate offsite power feed to XSW1DB, and that spurious operation of the breaker could cause a loss of XSW1DB. The licensee stated that ECR 50784 prescribed for cable ES M 73X to be partially replaced with a 3-hour fire rated cable, with the terminating junction boxes and remaining cable in the affected fire zones protected with ERFBS, however, the junction box and remaining cable in Fire Zone IB25.06 were not protected, therefore, the DROID is now resolved with a PB FRE per NFPA 805 4.2.4.2, Use of Fire Risk Evaluation.

DROID-IB25.06, 07 XSW1DB Failure The licensee stated that the NSCA and FPRA models are both impacted by a possible fire-induced failure to open the normal offsite power feed to XSW1DB, and that a failure to open the breaker could prevent other sources of power from energizing XSW1DB. The licensee stated that ECR 50784 prescribed for cable ES M 63X to be partially replaced with a 3-hour fire rated cable, with the terminating junction boxes and remaining cable in the affected fire zones protected with ERFBS, however, the junction box and remaining cable in Fire Zone IB25.06 were not protected, therefore, the DROID is now resolved with a PB FRE per NFPA 805 4.2.4.2, Use of Fire Risk Evaluation.

3.2.6.1 Licensees Defense-in-Depth Evaluation of Fire Area IB25 The licensee stated that the DID evaluation for Fire Area IB25 has been updated in the PB fire risk analysis to reflect the as-built configuration, which includes the adjustments in modification scope for Fire Area IB25. The licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA to ensure adequate DID is maintained. In particular, for this fire area, the LAR indicates that certain cables and junction boxes were not protected from fire damage.

The licensee stated that echelons 1 and 2 are captured in the frequencies of the fire scenarios applicable to the fire area. The licensee stated that automatic suppression systems exist in several fire zones of the fire area, however, in the FPRA, they were credited only in Fire Sub Zones IB25.01.01, IB25.01.02, IB25.01.03, IB25.01.04, and IB25.01.05. The licensee stated that manual suppression was credited in IB25.06.02. The licensee stated that in support of suppression (automatic or manual), credit was also taken for the installed detection systems in several sub-zones, and that for the remaining fire zones and sub-zones, detection and suppression features were not credited.

The licensee stated that there is no high-frequency fire in this fire area, and concluded that an adequate balance is maintained between echelons 1 and 2. The licensee stated that echelon 3 is captured via the average CCDP in the fire area. The licensee noted that the conditional LERF is not considered for this echelon because it is less than the CCDP, and as such the CCDP is in itself a sufficiently representative metric. The licensee stated that a fire scenario can be considered of high consequence if its frequency is more than 1E-06/yr and its CCDP is more than 0.1, and that there are no such high consequence scenarios in the fire area, thus, the balance of echelon 3 with the other echelons is maintained. The licensee concluded that the DID in this fire area is appropriate, given the suitable balance of its three echelons. Therefore, no improvements appear necessary.

3.2.6.2 NRC Staff Evaluation of Modifications to Fire Area IB25 The NRC staff reviewed the information provided by the licensee in the LAR including discussions of the impact of the proposed changes on risk, DID, and safety margins as required by NFPA 805, Section 4.2.4.2.

In regard to DID, the licensee stated that the PB fire risk analysis uses a qualitative analysis of the DID echelon balance, along with insights from the FPRA, to ensure adequate DID is maintained for Fire Area IB25. In particular, the LAR indicates that certain cables and junction boxes were not protected from fire damage, which potentially affects echelon 3. The licensee retained its separate risk criteria for echelons 1, 2, and 3 accepted for the NFPA 805 transition, which need to be met to achieve a balance among DID echelons. For example, with respect to echelon 3, the licensee established risk criteria for a high consequence fire scenario, whereby the frequency of the scenario needs to more than 1E-06/yr and the CCDP more than 0.1 for the scenario to be high consequence and for the DID echelon to not be met. The licensee indicated those additional risk criteria for the DID echelons are met for the fire scenarios in this fire area, and from this perspective a balance amongst DID echelons continues to be achieved.

In further regard to DID, the NRC staff determined that the proposed changes do not create an imbalance between any of the DID echelons. Not completing the modification to protect junction boxes and cables from fire damage has no impact on preventing fires from starting, or on detecting or extinguishing fires. The plant continues to provide an adequate level of fire protection so that a fire will not prevent essential safety functions from being performed. The NRC staff based this decision on the qualitative analysis supported by the separate risk criteria for high frequency and high consequence fire scenarios established for the DID echelons.

Because adequate DID exists for the affected fire area, the NRC staff concludes that DID is maintained.

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

In regard to PRA methods, the NRC staff finds that the specific PRA manipulation to fail cables and junction boxes from fire damage is within the state-of-practice in PRA. Also, the licensee indicated that the change to the PRA model for this descoped modification is based on methods from its original NFPA 805 LAR. Therefore, the NRC staff finds this PRA change to be acceptable.

3.2.7 NRC Conclusion on Plant Modifications to Table S-1, Plant Modifications Committed The NRC staff concludes that the proposed plant modifications and the PRA changes in the affected Fire Areas AB01, CB01, IB17, and IB25 are acceptable for use in the integrated PRA analysis.

3.3 Performance-Based Alternatives to NFPA 805 Requirements 3.3.1 NFPA 805, Section 3.3.4, Insulation Materials In the LAR dated August 29, 2018, the licensee submitted a new 10 CFR 50.48(c)(2)(vii) approval request for thermal insulation materials. The licensee stated that this new request identifies the discovery of thermal insulation materials, such as for insulation of system piping and equipment for anti-sweat purposes, and personnel protection (overhead bump hazards),

that do not meet the explicit requirements of NFPA 805, Section 3.3.4. Thus, the licensee requested NRC approval to allow existing and future usage of thermal insulation materials that do not meet the requirements of NFPA 805, Section 3.3.4, at Summer.

The licensee stated that NFPA 805, Section 3.3.4, states:

Thermal insulation materials, radiation shielding materials, ventilation duct materials, and soundproofing materials shall be noncombustible or limited combustible.

The licensee stated that NFPA 805, Section 1.6.36, has redefined earlier definitions of noncombustible material to the now current definition of limited combustible material:

Material that, in the form in which it is used, has a potential heat value not exceeding 3500 Btu/lb (8141 kJ/kg) and either has a structural base of noncombustible material with a surfacing not exceeding a thickness of 1/8 in.

(3.2 mm) that has a flame spread rating not greater than 50, or has another material having neither a flame spread rating greater than 25 nor evidence of continued progressive combustion, even on surfaces exposed by cutting through the material on any plane.

3.3.1.1 Licensees Request In Enclosure 1, Attachment 9, the licensee provided the basis for the request, including a DID and safety margin evaluation. The licensee stated that future installations of these insulation materials are controlled by the Engineering Change Process and that this control will ensure that the necessary fire protection reviews are completed, and new installations are evaluated for the potential affects that they could have on the fire safety analyses and the Fire PRA.

The licensee concluded that alternative approach outlined in the LAR achieves the following criteria:

Satisfies the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release; Maintains safety margins; and Maintains fire protection defense-in-depth (fire prevention, fire detection, fire suppression, mitigation, and post-fire safe shutdown capability).

3.3.1.2 NRC Staff Evaluation of the PB Alternative to NFPA 805, Section 3.3.4, Insulation Materials The NRC staff reviewed the information provided by the licensee in its LAR, which included discussions of the impact of the proposed change on the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release, DID, and safety margins as required by 10 CFR 50.48(c)(2)(vii).

The NRC staff determined that the proposed change has no impact on the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release because the insulation materials: (1) are installed in limited quantities throughout the plant; (2) are not installed in any large concentrations in each area; (3) will not contribute significantly to fire because they do not support continued progressive combustion; (4) meet the intent of the revised limited combustible material definition because the materials have a flame spread rating of 25 or less or are included in the FM methodology in the FPRA and any potential contribution is included in the FPRA CDF and LERF; and, (5) do not impact nuclear safety and do not compromise post-fire safe shutdown capability as analyzed previously.

The NRC staff determined that the proposed change has no impact on any of the DID echelons because the insulation materials are not considered a method for preventing fires from starting, or detecting, controlling, or extinguishing fires. In addition, the level of fire protection that will be provided so that a fire will not prevent essential safety functions from being performed is not changed because the limited quantities and concentrations of insulation materials do not impact the availability and reliability of fire protection systems and features.

The NRC staff also determined that the proposed change continues to maintain sufficient safety margins. The NRC staff determined that the change does not impact any codes and standards, or their alternatives accepted for use by the NRC because the licensee demonstrated that the insulation materials meet the flame spread and smoke developed criteria in ASTM E-84 and will not support progressive continued combustion. The NRC staff determined that the change does not impact any safety analysis acceptance criteria used in the licensing basis because the licensee demonstrated that the thermal insulation materials will not compromise automatic or manual fire suppression functions and post fire safe shutdown capability and are bound by the FPRA.

3.3.

1.3 NRC Staff Conclusion

of the PB Alternative to NFPA 805, Section 3.3.4, Insulation Materials Based on the above, the NRC approves the proposed performance-based alternative for the existing and future use of thermal insulation materials that do not meet the heat value content criteria of NFPA 805, Section 3.3.4, Insulation Materials.

3.3.2 NFPA 805, Section 3.3.5.1, Wiring Above Suspended Ceilings In its original NFPA 805 LAR, the licensee requested NRC approval of a PB method to demonstrate an equivalent level of fire protection for the requirement of NFPA 805, Section 3.3.5.1, for existing wiring in suspended ceilings (Approval Request L2). Specifically, the licensee stated that while the code section is prescriptive in the use and limitation of exposed electrical wire above suspended ceilings, there is existing wiring for non-essential, non-risk-significant areas and systems such as lighting and electrical power outlets that may not meet the explicit requirements of this section for those limited areas of the plant with suspended ceilings. In the NFPA 805 SE, the NRC approved the licensees Approval Request L2.

In the LAR dated August 29, 2018, the licensee stated that during third-party reviews additional areas in the plant where wiring is installed above suspended ceilings were identified. The licensee listed the following proposed revisions to the NRC acceptance of Approval Request L2:

Revising the request to simplify the statement that there are areas which have the non-compliant wiring. Additionally, SCE&G would like to clarify that the wiring consists of power cables, control cables, and energy limited communications cables, which are not listed for plenum use.

Revising the basis for request to include much of the discussion from FPE RAI 08, which was evaluated and approved by the NRC in the Safety Evaluation. The additional information identifies that the predominant type of wiring is for lighting with other installations of communication cables (phone, computer, video and security). These low energy communication cables are not considered a potential source of fire. Also included is the identification of installations with exposed IEEE-383-1974 and non-IEEE-383-1974 rated cable. SCE&G identifies that there are detection and automatic suppression systems installed in most of these areas which mitigates the hazard.

In the Nuclear Safety and Radiological Release Performance Criteria, SCE&G previously stated that engineering specifications and procedures are used to limit the amount of wiring above suspended ceilings. This statement is clarified to state the usage of engineering guidelines and specifications.

SCE&G also has identified the presence of detection and/or suppression systems as protection for these areas and that there are no nuclear safety or radiological concerns.

In the Safety Margin and Defense-in Depth, SCE&G has added additional information on the protection of the wiring above suspended ceilings to support the maintenance of the inherent safety margin. SCE&G also has clarified the types of non-compliance for wiring above suspended ceilings in the DID discussion. Clarification was also added to include the protection of structures, systems, and components important to safety.

SCE&G also completed minor editorial corrections throughout.

The licensee stated that approval is requested for existing wiring above suspended ceilings and that, while the code section is prescriptive in the use and limitation of exposed electrical wire above suspended ceilings, there is existing wiring that does not meet this requirement. The licensee stated that this wiring consists of power cables, control cables, and energy limited communications cables that are not listed for plenum use.

3.3.2.1 Licensees Request In Enclosure 1, Attachment 9, of the LAR, the licensee provided the basis for the request, including a DID and safety margin evaluation. The licensee stated that current plant guidelines and specifications regarding the installation of cables and wiring above suspended ceilings include limitations to prevent similar non-compliant installations in the future.

The licensee concluded that the Fire Protection Program engineering and administrative features and controls provide a level of risk management and performance that achieves the following criteria:

Satisfies the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release; Maintains safety margins; and Maintains fire protection defense-in-depth (fire prevention, fire detection, fire suppression, mitigation, and post-fire safe shutdown capability).

3.3.2.2 NRC Staff Evaluation of the PB Alternative to NFPA 805, Section 3.3.5.1, Wiring Above Suspended Ceilings The NRC staff reviewed the information provided by the licensee in its LAR, which included discussions of the impact of the proposed change on the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release, DID, and safety margins as required by 10 CFR 50.48(c)(2)(vii).

The NRC staff determined that the proposed change has no impact on the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release because: (1) the wiring above suspended ceilings is specified to be within metal conduits, cable trays, armored cable, or rated for plenum use; (2) there is limited installation of wiring above suspended ceiling whose additional hazards are mitigated by the presence of fire seals, detection, and/or automatic suppression systems; (3) the use of suspended ceilings is limited in risk significant areas important to the NSCA, FPRA, and NPO analysis; (4) the predominant cable found above suspended ceilings is used for lighting and meets the requirements of NFPA 805, Section 3.3.5.1; (5) communication cables (phone, computer, video, and security) which are typically not routed in conduit, are considered low energy and not considered a potential source of fire; (6) the majority of power production areas with suspended ceilings are designed with detection systems that are located above and/or below the suspended ceilings; and, (7) most areas are also provided with an automatic suppression system above and/or below the suspended ceiling.

The NRC staff determined that the proposed change has no impact on any of the DID echelons because the wiring above suspended ceilings is not considered a method for preventing fires from starting, or detecting, controlling, or extinguishing fires. In addition, the level of fire protection that will be provided so that a fire will not prevent essential safety functions from being performed is not changed because the limited quantities and concentrations of insulation materials do not impact the availability and reliability of fire protection systems and features.

The NRC staff also determined that the proposed change continues to maintain sufficient safety margins. The NRC staff determined that the change does not impact any codes and standards, or their alternatives accepted for use by the NRC because the licensee demonstrated that there are controls in place to restrict the installation of wiring above suspended ceilings and to protect the wiring when installed meet the intent of the NFPA Chapter 3 requirements. The NRC staff determined that the change does not impact any safety analysis acceptance criteria used in the licensing basis because the licensee demonstrated that the wiring above suspended ceilings will not compromise automatic or manual fire suppression functions and post fire safe shutdown capability.

3.3.

2.3 NRC Staff Conclusion

of the PB Alternative to NFPA 805, Section 3.3.5.1, Wiring Above Suspended Ceilings Based on the above, the NRC approves the proposed revisions to the NRC acceptance of Approval Request L2, as provided in the August 29, 2018, LAR.

3.4 Addressing NCVs Related to the NFPA 805 Licensing Basis In the LAR dated August 29, 2018, the licensee included an enclosure to revise the NFPA 805 licensing basis to address issues identified in the following NCVs.

Fire Doors IB105A and IB105B, the subject of NCV 05000395/2016001-01 and Violation 05000395/2016007-01.

RCP Lube Oil Collection System, the subject of Violation 05000395/2017002-01, NCV 05000395/2017002-02, and NCV 5000395/2013003-03.

3.4.1 Fire Doors IB105A and IB105B NCV The licensee stated that DRIB/105A and DRIB/105B are Class A fire doors installed in a back-to-back configuration on the same frame within the 3-hour fire rated barrier between the Heating, Ventilation, and Air Conditioning (HVAC) Water Chiller Pump A Room (Fire Zone IB07.01) and the HVAC A Water Chiller Room (Fire Zone IB23.01), and that due to the unique construction of these doors, closing devices were not installed. The licensee stated that the NEI 04-02 Table B-1 in the original NFPA 805 LAR did not refer to this fact and that this omission has been the subject of NRC inspection findings severity level IV NCV 05000395/ 2016001-01 and Notice of Violation (VIO)05000395/2016007-01.

The licensee stated that, to address these violations, it has modified the doors to maintain them in the closed position and that the doors cannot be physically opened without the aid of tools.

The licensee stated that it has analyzed the condition of fire doors IB105A and IB105B for adequacy and that an engineering evaluation has been developed which evaluates the installation of fire doors IB105A and IB105B as acceptable. The licensee stated that the evaluation is documented in an engineering equivalency evaluation and that the NFPA 805 Chapter 3 code compliance table, currently maintained in the Fire Protection Design Basis Document (FP DBD) has been revised to reflect the change.

The licensee stated that the NFPA 80 code compliance calculation has been revised and addresses the issue and that the Reference Document ID for the applicable technical report identified in the original NFPA 805 LAR was incorrect and has been corrected.

The NRC staff reviewed the information provided by the licensee and determined that, in a letter dated December 20, 2016 (Reference 29), the licensee responded to the Notice of Violation, and indicated the corrective steps that have been taken, the corrective steps that will be taken, and the date when full compliance will be achieved. The licensee stated that full compliance will be achieved after the LAR dated August 29, 2018, is approved by the NRC in a subsequent SE.

In a letter dated January 18, 2017 (Reference 30), the NRC responded to the licensee and indicated that the corrective actions appear to be adequate and will be examined during a future inspection.

3.4.1.1 NRC Staff Evaluation of Fire Doors IB105A and IB105B NCV The NRC staff reviewed the information provided by the licensee and determined that the LAR includes revisions to the original NFPA 805 LAR Attachment A, NEI 04-02, Table B-1 Transition of Fundamental Fire Protection Program and Design Elements, for NFPA 805, Section 3.11.3(1), NFPA 80, Standard for Fire Doors and Fire Windows. The revisions include changes to the references and the compliance basis, with the compliance basis including the statement, Other evaluations also exist for miscellaneous door assemblies. The NRC staff finds the condition acceptable because the licensee modified the doors to maintain them in the closed position, conducted an engineering evaluation that evaluates the installation of the fire doors, and revised its compliance strategy to reflect these changes.

NRC staff notes that VIO 05000395/2017002-01 was closed during the October 2019 Triennial Fire Protection Inspection 05000395/2019012 (Reference 31).

3.4.2 Reactor Coolant Pump Lube Oil Collection System NCV The licensee stated that Approval Request L12 was submitted in accordance with 10 CFR 50.48(c)(2)(vii) in a letter dated October 14, 2013 (Reference 32), for NFPA 805 Section 3.3.12(a) RCPs and that the approval request was for the potential of oil misting from the RCPs due to normal motor consumption not captured by the oil collection system designed for pressurized and non-pressurized leakage and spillage. The licensee stated that deficiencies associated with this approval request have been identified by NRC inspectors and stated that the RCP oil collection system is designed and was reviewed in accordance with 10 CFR 50, Appendix R, Section III.O, to collect leakage from credible pressurized and non-pressurized leakage sites in the RCP oil system, when, in fact, an NRC-identified Green NCV 05000395/2013003-03, Failure to Adequately Design, Install and Maintain Oil Collection Devices for Reactor Coolant Pump Motors, had not been resolved. The licensee stated that the approval request used the word credible in place of potential when discussing leakage sites.

The licensee stated that these deficiencies were captured as Violation 05000395/2017002-01, Failure to Implement Corrective Actions to Restore Compliance for Previous NRC identified Green NCV 05000395/2013003-03 and Severity Level IV NCV 05000395/2017002-02, Failure to Provide NRC Staff Complete and Accurate Information (Reference 9). The licensee stated that its reply to the Notice of Violation (NOV) dated September 6, 2017 (Reference 33), included the following corrective step that will be taken:

ECR 50909, RCP Oil Enclosure, will be implemented during RF24. This ECR will ensure compliance with NFPA 805 for RCP oil collection requirements by modifying the oil lift pump enclosures, and fill and drain enclosures, and drip pans as necessary. This ECR will also address oil drips from the RCP exhaust duct to motor flange joint.

The NRC staff reviewed the information provided by the licensee and determined that, in the letter dated September 6, 2017, the licensee responded to the NOV, and indicated the corrective steps that have been implemented, the corrective steps that will be implemented, and the date when full compliance will be achieved. The licensee implemented a bridging strategy until the implementation of ECR 50909, during RF24, and that compensatory measures remain in effect until full compliance is achieved.

3.4.2.1 NRC Staff Evaluation of Reactor Coolant Pump Lube Oil Collection System NCV Although the licensee did not propose any licensing basis changes to Approval Request L12, the NRC staff found that the statement the licensee made indicating that the oil collection system is designed and was reviewed in accordance with 10 CFR 50, Appendix R, Section III.O to collect leakage from credible pressurized and non-credible leakage sites in the RCP oil system will be accurate upon completion of ECR 50909. Therefore, the PB method continues to be an acceptable alternative to the corresponding NFPA 805, Section 3.3.12(1), requirement because it satisfies the performance goals, performance objectives, and performance criteria specified in NFPA 805 related to nuclear safety and radiological release, maintains sufficient safety margins, and maintains adequate fire protection DID.

NRC staff notes that ECR 50909 was implemented on the installed RCPs during RF24. ECR 50909 implementation status was reviewed by NRC staff during the October 2019 Triennial Fire Protection Inspection 05000395/2019012. Following review, NOV 05000395/2017002-01 was closed.

3.5 Clarification and Editorial Corrections to NFPA 805 Licensing Basis The licensee stated that following NRC issuance of Amendment No. 199 to Renewed License No. NPF-12 dated February 11, 2015, and its enclosed NFPA 805 SE, an independent party performed an assessment of compliance with the NFPA 805 licensing basis and that the results of this assessment included the identification of statements in the NFPA 805 SE that are inconsistent with actual plant conditions. The licensee noted that this was due to erroneous statements in the original LAR submittal or in response to RAIs. The items are described below:

3.5.1 Correction to the February 11, 2015, NFPA 805 SE, Section 3.1.4.4, Bulk Gas Storage Tanks The licensee stated that the assessment identified that the second paragraph of the NFPA 805 SE, Section 3.1.4.4, Bulk Gas Storage Tanks, should be clarified regarding the storage pressure of six hydrogen cylinders located outside the protected area south of the turbine building.

The licensee stated that the text of Section 3.1.4.4 states that, the cylinders are maintained at 2400 psig, however, 2400 psig is the design pressure of the cylinders and is used to calculate their maximum total storage capacity and actual plant conditions maintain the cylinders at a pressure less than 2400 psig, in accordance with standard operating procedures. In a letter dated October 10, 2012Property "Letter" (as page type) with input value "RC-12-0142, License Amendment Request - LAR-06-00055, License Amendment Request to Adopt NFPA 805, Response to Request for Additional Information" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process. (Reference 34), the licensee stated that the storage bottles at 2400 psig have a total capacity of 44,800 scf.

To accurately reflect plant conditions and operating procedures, the licensee proposed a clarification to the text in NFPA 805 SE, Section 3.1.4.4, second paragraph to indicate that the cylinders are maintained at less than 2400 psig. The licensee stated that the proposed clarification is to ensure correct understanding of the plant conditions and does not represent a change to the physical configuration or control of the plant.

NRC Staff Evaluation

The NRC staff reviewed the information submitted by the licensee, the NFPA 805 SE, and the licensees letter dated October 10, 2012Property "Letter" (as page type) with input value "RC-12-0142, License Amendment Request - LAR-06-00055, License Amendment Request to Adopt NFPA 805, Response to Request for Additional Information" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., and agrees with the licensee that 2400 psig is the design pressure of the cylinders that is used to calculate their maximum total storage capacity.

The NRC staff also agrees with the licensees proposed change to indicate that the cylinders are maintained at less than 2400 psig. The NRC staff concludes that this clarification does not change the NRC staffs previous conclusion that the PB method continues to maintain the performance goals, objectives, and criteria specified in NFPA 805 related to nuclear safety and radiological release, maintains sufficient safety margin, and maintains adequate fire protection defense-in-depth.

3.5.2 Correction to the February 11, 2015, NFPA 805 SE, Section 3.4.2.2, Fire PRA Model The licensee stated:

The assessment identified that [NFPA 805] Safety Evaluation (SE)

Section 3.4.2.2, Fire PRA Model, paragraph 6 required a clarification on the number of scenarios provided in an additional response (Reference 35) to PRA RAI 68 (Reference 36).

In its response to PRA RAI 68 it was stated:

...that the total of 170 new scenarios were added to the Fire PRA model for the ungrouped transient zones. The assessment found that only 154 scenarios were listed in the design calculation.

The licensee stated:

Subsequent to the RAI response, 16 scenarios were determined not to be required, as a fire would not spread to adjacent transient zone via trays and that over time scenarios have been added and deleted during the FPRA maintenance process. The licensee stated that the list of ungrouped transient zones scenarios is currently maintained in a design calculation.

NRC Staff Evaluation

The NRC staff reviewed the information submitted by the licensee, the licensees response to PRA RAI 68 and the NFPA 805 SE. The NRC staff determined that the change in the number of scenarios in the original RAI response (170 to 154) does not affect the NFPA 805 SE conclusion. The NRC staff finds that the FPRA model appropriately captures fire spread to adjacent transient zones containing cable trays that extend across transient zone boundaries because the 16 scenarios are not currently included in the design calculation documentation do not affect the FPRA and adding and deleting scenarios is part of the normal FPRA maintenance process.

3.5.3 Correction to the February 11, 2015, NFPA 805 SE, Section 3.4.2.3.2, RAls Pertaining to Fire Modeling in Support of the VCSNS FREs (regarding Hot Gas Layer)

The licensee stated:

A. The assessment identified that [NFPA 805] Safety Evaluation (SE)

Section 3.4.2.3.2, RAls Pertaining to Fire Modeling (FM) in Support of the Summer Fire Risk Evaluations (FREs), required correction regarding the gap size assumptions used in fire modeling. The [NFPA 805] Safety Evaluation text states that the Hot Gas Layer (HGL) calculations assume an opening of 0.5 inch (one-half of an inch) below all doors, which is consistent with NUREG/CR-6850, for scenarios with closed doors and without mechanical ventilation, however, certain HGL calculations are not consistent with this statement.

The response to FM RAI 01.i (Reference 34) incorrectly stated that for performance based hot gas layer calculations, the 0.5 inch opening corresponds to a leakage area fraction of 0.003, rather than the correct value of 0.006. A leakage area fraction of 0.003 corresponds to a 0.25 inch opening. The performance based fire modeling [PB FM] compliance strategy has been transitioned to a fire risk evaluation [FRE] compliance strategy as part of the LAR. The performance based fire modeling insights will no longer be used The response to FM RAI 01.i regarding the use of a 0.03 leakage area fraction for individual zone reports for HGL calculations is accurate.

The response to FM RAI 01.i also states, several sensitivity cases were run for the hot gas layer [HGL] CFAST [consolidated model of fire and smoke transport] calculations in which the equivalence ratio for the natural ventilation case was outside of the validation range. In cases when the leakage area fraction was increased to bring the equivalence ratio into the validation range, the conclusions were unchanged.

NRC Staff Evaluation

The NRC staff reviewed the information submitted by the licensee and agrees with the licensee that a 0.5 inch opening corresponds to 0.006 and that a 0.25 inch opening corresponds to 0.003. The NRC staff determined that the corrected response does not impact the conclusion in the NFPA 805 SE that the use of a 0.5 inch opening below every door for scenarios with closed doors and without mechanical ventilation has no significant impact on the time to abandonment or probability of abandonment, and also maintains acceptability of the RAI response because the licensee demonstrated that a fractional leakage area from 0.001 to 0.03 has no significant impact on the time to abandonment or probability of abandonment and the revised value of 0.006 is within the range of 0.001 to 0.03.

3.5.4 Correction to the February 11, 2015, NFPA 805 SE, Section 3.4.2.3.2, RAls Pertaining to Fire Modeling in Support of the VCSNS FREs (regarding Crediting Sprinklers)

The licensee stated:

B. The assessment also identified that [NFPA 805] SE Section 3.4.2.3.2, RAIs Pertaining to Fire Modeling in Support of the VCSNS Fire Risk Evaluations (FREs), required correction regarding calculations of sprinkler activation located near the ceiling. The [NFPA 805] Safety Evaluation text states, in response to FM RAI 01.t.iii, since sprinklers are not credited for activating until after 20 minutes, the licensee assumed that all targets within the initiating transient zone would be damaged and that sufficient smoke would be generated to allow for smoke detection and sprinkler activation for sprinklers outside the initial transient zone.

The Safety Evaluation text addressing FM RAI 01.t in [NFPA 805] SE Section 3.4.2.3.2 only addressed the information contained in the Oct 2012 RAI (Reference 34) response RC-12-0142 and did not include updated information that was submitted in a later response to FM RAI 01.01 from Oct 2013 (Reference 37) (RC-13-0142). The later response states:

The fire dynamic tools (FDT) for heat detector response times (Chapter 12, NUREG-1805) and sprinkler response time (Chapter 10, NUREG-1805) are no longer used to justify sprinkler activation in any of the fire zones.

The licensee stated:

sprinkler heads located close to the ceiling are not credited until ZOI targets are damaged. That is, the sprinklers will not be credited in protecting the tray nearest to the ignition source but will be credited in preventing propagation after damage to the nearest trays.

The licensee stated in response to the RAI that:

conservatism is achieved by assuming the ZOI targets are damaged before suppression starts. That is, there is no credit for suppression for the ignition source and targets within the ZOI.

The licensee provided the example of the approach in the RAI response:

the sprinkler will not be credited in protecting the nearby tray. However, it will be credited in preventing propagation after damage to the nearby tray is assumed.

NRC Staff Evaluation

The NRC staff reviewed the information submitted by the licensee, the NFPA 805 SE, and previous RAI response letters and determined that the licensee revised the fire scenario for IB25.01.02 as discussed in its response to FM RAI 01.01 and PRA RAI FM RAI 01.n applies to IB25.01.02. In the NFPA 805 SE, the NRC staff concluded that the licensees response to FM RAI 01.n was acceptable because the approach provides adequate justification that detector activation times were conservatively determined by increasing the distance between the fire and the detector and by assuming the ZOI targets are damaged before suppression starts. In this case the licensee stated that sprinkler heads located close to the ceiling are not credited until the ZOI targets are damaged, and that the sprinklers will not be credited in protecting the tray nearest to the ignition source but will be credited in preventing propagation after damage to the nearest trays. The NRC staff finds this approach acceptable for performing a FRE on IB25.01.02 because the approach provides adequate justification that detector activation times were conservatively determined by increasing the distance between the fire and the detector and by assuming the ZOI targets are damaged before suppression starts.

3.5.5 Correction to the February 11, 2015, NFPA 805 SE, Section 3.4.2.3.2 (regarding Probability of Abandonment in the MCR)

The licensee stated that:

C. The assessment also identified in [NFPA 805] SE Section 3.4.2.3.2 an issue that requires clarification, regarding the impact on the probability of abandonment in the MCR when considering transient fire heat release rates

[HRRs] and average growth rates. The original response in letter RC-12-0142 to FM RAI 01.g erroneously stated that:

The peak heat release rate for transients is 317 kW. Therefore, it was assumed that the CFAST simulations available would bound the results for the transient regardless of the faster growth rate as a peak of 317 kW is not expected to produce abandonment conditions based on CFAST results for the different ventilation conditions evaluated.

it did not address the case of non-functioning HVAC for electrical cabinet fire average growth rates. For the case of a non-functioning HVAC system, the MCR abandonment time calculations show a heat release rate of approximately 197 kW is necessary to cause abandonment which is less than the 317 kW 98th percentile peak heat release rate for transient fires.

For the 197 kW electrical cabinet fire, the CFAST results show time to abandonment of 12 minutes. For a transient fire, with a peak of 317 kW (98th percentile fire) and a time to peak of 8 minutes per NUREG/CR-6850, Supplement 1 (page 17-2) for transient fires in a trash can, the time to reach 197 kW is calculated to be 6.3 minutes The current MCR abandonment calculations are based on electrical cabinet fires that have 12 minute growth rates. The MCR probability of abandonment calculations of non-suppression probability subtract 5 minutes from the calculated abandonment time. The 5 minutes is identified as time to suppression, however, the latest guidance from NUREG/CR-6850 Supplement 1 recommends that the probability of non-suppression be calculated as time to damage (or in this case, time to abandonment) minus time to detection (which is zero for the continually manned control room).

Therefore, the current calculation of time to abandonment, based on a time to peak HRR of 12 minutes and reduced by a 5 minute time to suppression, is similar to the time to abandonment calculation for the case of a time to peak HRR of 7 minutes, without the 5 minute time to abandonment reduction.

A comparison of the non-suppression probability for the electrical fire with suppression after 7 minutes and a transient fire with suppression after 6.3 minutes shows a value of 0.10 for the electrical cabinet and 0.13 for the transient fire.

A sensitivity calculation shows that calculating the probability of abandonment using the transient fire heat release rate [HRR], rather than the electrical cabinet heat release rate [HRR] has a small impact on the results:

an increase of 1E-8 in CDF and a decrease of 2E-11 in LERF.

NRC Staff Evaluation

The NRC staff reviewed the information submitted by the licensee and determined that the corrected information on the MCR abandonment times is acceptable for risk evaluation because the sensitivity study shows only a minor impact on CDF and LERF which does not affect the conclusion in the NFPA 805 SE that transient fires resulting in MCR abandonment are unlikely.

3.5.6 Correction to the February 11, 2015, NFPA 805 SE, Section 3.5.1.8, Plant Fire Barriers and Separations The licensee stated that:

The assessment identified that [NFPA 805] Safety Evaluation (SE)

Section 3.5.1.8, Plant Fire Barriers and Separations, required an update regarding underground electrical duct banks near the Diesel Generator building.

This distance was erroneously provided in RC-14-0027 "[letter" contains a listed "[" character as part of the property label and has therefore been classified as invalid. (Reference 38)

The [NFPA 805] SE makes the statement that single channel duct banks within Fire Area DB are isolated from one another by 30 feet. Contrary to this statement, actual spacing of the duct banks varies.

It was identified that spacing between 1A and 1B single channel duct banks varies in Fire Area DB. In some instances, the edge-to-edge separation is less than 20 feet, but greater than 10 feet. The varied separation was evaluated and determined to have no impact on the Fire Risk Evaluation, as the duct banks are encased in concrete and buried. The soil and concrete provide an adequate level of protection against fire damage to both channels.

NRC Staff Evaluation

The NRC staff reviewed the information submitted by the licensee and determined that the edge separation distance between the 1A and 1B single channel duct banks of less than 20 feet but greater than 10 feet is acceptable because the separation distance has no impact on the FREs and the duct banks are encased in concrete and buried underground.

3.5.7 Correction to the February 11, 2015, NFPA 805 SE, Table 3.5-2 The licensee stated:

Table 3.5-2, Previously Approved Licensing Actions Being Transitioned The assessment identified a discrepancy in Safety Evaluation (SE) Table 3.5-2, based on inaccurate information provided in LAR-06-00055 [the original NFPA 805 LAR, dated November 15, 2011] (Reference 19), Attachment K, Existing Licensing Action Transition. Specifically, in the details and basis of LA-IB25-02 of LAR 06-00055, Attachment K [which concerned the lack of a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire rated barrier in the intermediate building.]

SCE&G requested a deviation from Appendix R III.G.2 criteria for Intermediate Building (IB) Fire Area IB25 in a [[letter::05000395/LER-1985-013, :on 850429,reactor Trip Occurred Due to lo-lo Steam Generator Water Level in Steam Generator B. Caused by Transients in Deaerator Tank Level & Main Feedwater Pump Discharge Pressure|letter dated May 29, 1985]] (Reference 39). This deviation was later withdrawn, and that a second deviation was requested for the same Fire Areain a letter dated April 23, 1986 (Reference 40). The NRC approved this deviation request in a Safety Evaluation (SE) dated July 27, 1987 (Reference 41).

The licensee stated that the information in the original NFPA 805 LAR, Attachment K was based on the withdrawn deviation.

The erroneous reference to the original deviation request also contributed to several errors in the description of an engineering evaluation included in LAR-06-00055 [the original NFPA 805 LAR] Attachment C. [The licensee provided corrections to its original NFPA 805 LAR, Attachment C.]

NRC Staff Evaluation

The NRC staff reviewed the information submitted by the licensee, the original NFPA 805 LAR Attachment K, and the NFPA 805 SE. The NRC staff determined that the conclusion reached in the NFPA 805 SE that transition of LA-IB25-02 is acceptable and is not impacted because previous approval was based on the correct version of the SE dated July 7, 1987. The NFPA 805 SE states, [b]ased on the previous staff approval of this deviation in an SE dated July 7, 1987, and inclusion in the existing FP license condition, and the statement by the licensee that the basis remains valid, the NRC staff concludes that transition of this licensing action is acceptable. In accordance with NFPA 805, Section 3.1, previously approved alternatives from the fundamental FPP attributes of NFPA 805, Chapter 3, take precedence over the requirements of NFPA 805 Chapter 3.

Although the NFPA 805 SE references the correct SE dated July 7, 1987, NFPA 805 SE Table 3.5-2 for LA-IB25-02 discusses information from the licensees [[letter::05000395/LER-1985-013, :on 850429,reactor Trip Occurred Due to lo-lo Steam Generator Water Level in Steam Generator B. Caused by Transients in Deaerator Tank Level & Main Feedwater Pump Discharge Pressure|May 29, 1985, letter]] which was withdrawn, and not its April 23, 1986, letter which was the basis for the July 7, 1987 SE.

The NRC staff agrees with the licensees proposed revision to Table 3.5-2 for LA-IB25-02 to reflect information from the April 23, 1986, letter as shown below:

Licensing Action Description Applicable Fire Areas

NRC Staff Evaluation

LA-IB25 Appendix R Deviation, Intermediate Building -

Lack of 1-hour fire rated barrier (III.G.2.c criteria)

IB25 The basis for approval as described by the licensee in LAR Attachment K is redundant circuits are separated vertically by a reinforced concrete floor/ceiling assembly with unprotected openings. Automatic suppression is provided in Fire Zone IB25.01 at El. 412. Automatic detection is provided in Fire Zone IB25.01 at El. 412 and IB25.06 at El. 436. 1-hr ERFBS is provided for Train A cables at El. 412.

Penetrations in the floor/ceiling assembly are sealed for the SW Booster Pump Train A cables, and for penetrations directly above the redundant Train B cables.

Manual fire suppression is provided by interior manual hose stations and portable extinguishers.

Based on the previous staff approval of this deviation in an SE dated 7/27/87, and inclusion in the existing FP license condition, and the statement by the licensee that the basis remains valid, the NRC staff concludes that transition of this licensing action is acceptable.

3.

5.8 NRC Staff Conclusion

Regarding the Proposed Clarification and Editorial Corrections to NFPA 805 Licensing Basis The NRC staff concludes that the licensee proposed clarifications and editorial corrections to the February 11, 2015, NFPA 805 SE, are acceptable and do not change any of the conclusions discussed in the NFPA 805 SE. This safety evaluation establishes the revised licensing basis for those clarifications and editorial corrections.

3.6 RFOL No. NPF-12 Proposed Changes NRC staff reviewed the licensees proposed changes to Summers RFOL and find the changes acceptable.

3.7 NRC Staff Conclusion

The NRC staff reviewed the licensees LAR to descope modifications in Fire Areas AB01, CB01, IB17, and IB25, to use PB methods as alternatives to compliance with NFPA 805 Section 3.3.4 and 3.3.5.1, and to make several clarifications and editorial corrections to its RI/PB FPP in accordance with the requirements of 10 CFR 50.48(c) and NFPA 805. The licensees LAR identified revisions to license conditions in accordance with 10 CFR 50.48(c)(3)(i). The changes proposed by the licensee included a review of compliance, risk, DID, and safety margins (as applicable), as required by NFPA 805, Section 4.2.4.2. The NRC staff concludes that the licensees 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). In addition, the NRC staff concludes that (1) the effect of the proposed changes to the FPP can be assessed using the PRA methods and approaches previously accepted by the NRC staff, (2) the general changes to the PRA model are consistent with methods and approaches previously accepted by the NRC staff, and (3) the licensee used acceptable changes to its PRA from NUREG-2169, NUREG-2178, and NUREG-2180.

The licensee adjusted its calculation of the change in risk by removing the Alternate Seal Injection plant modification from the compliant plant model, which is an acceptable manipulation in this case to remove unnecessary conservatism in the change in risk results. As a result, according to the licensees response to PRA RAI 3 in its letter dated October 9, 2019, the final change in CDF and change in LERF are negative, with the CDF being -1.4E-04 per year and the LERF being -2.8E-06 per year. The total reported CDF is 8.9E-05 per year and total reported LERF is 6.0E-06 per year. The additional CDF of RAs is 8.1E-06 per year and the additional LERF of RAs is 2.0E-07 per year. Updates to the seismic PRA were reported in the licensees October 9, 2019 letter, but the NRC staff did not review the seismic PRA and has no view on the acceptability of the reported seismic PRA results. However, since the change in risk for the LAR is negative, the decision on whether the change in CDF and LERF is acceptable does not rely on the total CDF and LERF estimates. Therefore, the risk meets the acceptance guidelines of RG 1.174 and RG 1.205.

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 a change in CDF and change in LERF which are negative and thus 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 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.

For the clarifications and editorial corrections submitted by the licensee, the NRC staff concludes they are acceptable, and this SE establishes the revised licensing basis for those items.

4.0 STATE CONSULTATION

In accordance with the Commissions regulations, the South Carolina State official was notified of the proposed issuance of the amendment on January 7, 2020. On January 7, 2020, the State official confirmed that the State of South Carolina had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes requirements with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts and no significant change in the types of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding published in the Federal Register on December 4, 2018 (83 FR 62609). Accordingly, the amendment meets 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 amendment.

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 Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

7.0 REFERENCES

1 Lippard, George, A., South Carolina Electric and Gas Company, letter to U.S. Nuclear Regulatory Commission, "Virigil C. Summer Nuclear Station (VCSNS) Unit 1, Docket No.

50-395, Operating License No. NPF-12, License Amendment Request - LAR-16-01490 National Fire Protection Association (NFPA) Standard 805 Program Revisions," August 29, 2018 (ADAMS Accession No. ML18242A658).

2 Lippard, George, A., Dominion Energy South Carolina, letter to U.S. Nuclear Regulatory Commission, "South Carolina Electric & Gas Company, Virgil C. Summer Nuclear Station (VCSNS) Unit 1, License Amendment Request - LAR-16-01490 NFPA 805 Program Revisions, Response to Request For Additional Information," April 29, 2019 (ADAMS Accession No. ML19119A365).

3 Lippard, George, A., Dominion Energy South Carolina, letter to U.S. Nuclear Regulatory Commission, "South Carolina Electric & Gas Company, Virgil C. Summer Nuclear Station (VCSNS) Unit 1, License Amendment Request - LAR-16-01490 NFPA 805 Program Revisions, Response to Request For Additional Information," May 22, 2019 (ADAMS Accession No. ML19150A696).

4 Lippard, George, A., Dominion Energy South Carolina, letter to U.S. Nuclear Regulatory Commission, "South Carolina Electric and Gas Company, Virgil C. Summer Nuclear Station (VCSNS) Unit 1, License Amendment Request - LAR-16-01490, NFPA 805 Program Revisions, Response to NRC Follow-up Question PRA RAI 03," August 12, 2019 (ADAMS Accession No. ML19224B115).

5 Lippard, George, A., Dominion Energy South Carolina, letter to U.S. Nuclear Regulatory Commission, "South Carolina Electric and Gas Company, Virgil C. Summer Nuclear Station (VCSNS) Unit 1, License Amendment Request - LAR-16-01490, NFPA 805 Program Revisions, Response to NRC Follow-up Question to PRA RAI 03," October 9, 2019 (ADAMS Accession No. ML19282E261).

6 National Fire Protection Association, "Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants," Standard 805 (NFPA 805), 2001 Edition, Quincy, Massachusetts.

7 Williams, Shawn, U.S. Nuclear Regulatory Commission, letter to Gatlin, Thomas, D., South Carolina Electric & Gas Company, "Virgil C. Summer Nuclear Station, Unit 1 - Issuance of Amendment Regarding Transition to Risk-Informed, Performance-Based Fire Protection Program In Accordance with 10 CFR 50.48(c) (TAC NO. ME7586)," February 11, 2015 (ADAMS Accession No. ML14287A289).

8 Davis, Bradley, J., U.S. Nuclear Regulatory Commission, letter to Lippard, George, South Carolina Electric & Gas Company, "Virgil C. Summer Nuclear Station - NRC Problem Identification and Resolution Inspection Report 05000395/2016007 and Notice of Violation,"

November 22, 2016 (ADAMS Accession No. ML16327A378).

9 Masters, Anthony, D., U.S. Nuclear Regulatory Commission, letter to Lippard, George, A.,

South Carolina Electric & Gas Company, "Virgil C. Summer Nuclear Station, Unit 1 - NRC Integrated Inspection Report 05000395/2017002 and Notice of Violation," August 9, 2017 (ADAMS Accession No. ML17221A115).

10 McCoy, Gerald, J., U.S. Nuclear Regulatory Commission, letter to Gatlin, Thomas, D.,

South Carolina Electric & Gas Company, "Virgil C. Summer Nuclear Station, Unit 1 - NRC Integrated Inspection Report 05000395/2013003," August 6, 2013 (ADAMS Accession No. ML13218A334).

11 U.S. Nuclear Regulatory Commission, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis,"

Regulatory Guide (RG) 1.174, Revision 3, January 2018 (ADAMS Accession No. ML17317A256).

12 U.S. Nuclear Regulatory Commission, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities," RG 1.200, Revision 2, March 2009 (ADAMS Accession No. ML090410014).

13 U.S. Nuclear Regulatory Commission, "Risk-Informed, Performance-Based Fire Protection for Existing Light-Water Nuclear Power Plants," RG 1.205, Revision 1, December 2009 (ADAMS Accession No. ML092730314).

14 Nuclear Energy Institute, "Guidance for Implementing a Risk-Informed, Performance-Based Fire Protection Program Under 10 CFR 50.48(c)," NEI 04-02, Revision 2, Washington, DC, April 2008 (ADAMS Accession No. ML081130188).

15 U.S. Nuclear Regulatory Commission, "EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities, Volume 1: Summary and Overview," NUREG/CR-6850, September 2005 (ADAMS Accession No. ML052580075).

16 U.S. Nuclear Regulatory Commission, "EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities, Volume 2: Detailed Methodology," NUREG/CR-6850, September 2005 (ADAMS Accession No. ML052580118).

17 U.S. Nuclear Regulatory Commission, "Fire Probabilistic Risk Assessment Methods Enhancements," NUREG/CR-6850, Supplement 1, September 2010 (ADAMS Accession No. ML103090242).

18 American Society of Mechanical Engineers (ASME) and American Nuclear Society (ANS),

"Addenda to ASME/ANS RA-S-2008, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications," ASME/ANS RA-Sa-2009, Februrary 2, 2009.

19 Gatlin, Thomas, D., South Carolina Electric and Gas Company, letter to U.S. Nuclear Regulatory Commission, "License Amendment Request-LAR-06-00055, License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants (2001 Edition)," November 15, 2011 (ADAMS Accession No. ML11321A172).

20 U.S. Nuclear Regulatory Commission, "Refining and Characterizing Heat Release Rates from Electrical Enclosures During Fire (RACHELLE-FIRE), Volume 1: Peak Heat Release Rates and Effect of Obstructed Plume," NUREG-2178, April 2016 (ADAMS Accession No. ML16110A140).

21 U.S. Nuclear Regulatory Commission, "Nuclear Power Plant Fire Ignition Frequency and Non-Suppression Probability Estimation Using the Updated Fire Events Database,"

NUREG-2169 and EPRI 3002002936, January 2015 (ADAMS Accession No. ML15016A069).

22 U.S. Nuclear Regulatory Commission, "Determining the Effectiveness, Limitations, and Operator Response for Very Early Warning Fire Detection Systems in Nuclear Faculties (DELORES-VEWFIRE): Final Report," NUREG-2180, December 2016 (ADAMS Accession No. ML16343A058).

23 Klein, Alexander R., U.S. Nuclear Regulatory Commission, memorandum to file, "Closeure of National Fire Protection Association 805 Frequently Asked Question 08-0046: Incipient Fire Detection Systems," November 23, 2009 (ADAMS Accession No. ML093220426).

24 U.S. Nuclear Regulatory Commission, "Joint Assessment of Cable Damage and Quantification of Effects from Fire (JACQUE-FIRE): Final Report," NUREG/CR-7150, Volume 2, BNL-NUREG-98204-2012, EPRI 3002001989, May 2014 (ADAMS Accession No. ML14141A129).

25 U.S. Nuclear Regulatory Commission, "EPRI/NRC-RES Fire Human Reliability Analysis Guidelines, Final Report," July 2012 (ADAMS Accession No. ML12216A104).

26 Williams, Shawn, U.S. Nuclear Regulatory Commission, E-Mail to Moore, Michael, S., South Carolina Electric & Gas Company, "Virgil C. Summer Nuclear Station, Unit No. 1 - Request for Additional Information RE: LAR-16-01490 NFPA 805 Program Revisions (EPID No. L-2018-LLA-0233)," March 13, 2019 (ADAMS Accession No. ML19072A144).

27 U.S. Nuclear Regulatory Commission, "Fire Dynamics Tools (FDTs) Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program," NUREG-1805, Supplement 1, Volumes 1 & 2, July 2013 (ADAMS Accession No. ML13211A098).

28 Westinghouse Electric Company, LLC, "Model for Failure of RCP Seals Given Loss of Seal Cooling in CE NSSS Plants," WCAP-16175-NP-A, Rev. 0, March 2007 (ADAMS Accession No. ML071130383).

29 Lippard, George, A., South Carolina Electric & Gas Company, letter to U.S. Nuclear Regulatory Commission, "Virgil C. Summer Nuclear Station (VCSNS) Unit 1, Docket No. 50-395, Operating License No. NPF-12, Reply to Notice of Violation," December 20, 2016 (ADAMS Accession No. ML16355A277).

30 Davis, Bradley, J., U.S. Nuclear Regulatory Commission, letter to Lippard, George, A.,

South Carolina Electric & Gas Company, "Reply to South Carolina Electric and Gas Company Letter Dated December 20, 2016, Regarding Response to Inspection Report No.

05000395/2016007 and Notice of Violation, Virgil C. Summer Nuclear Station, Unit 1,"

January 18, 2017 (ADAMS Accession No. ML17019A207).

31 Scott, M., U.S. Nuclear Regulatory Commission, letter to Daniel G. Stoddard, Dominion Energy Shaeffer, "Virgil C. Summer Nuclear Station - Triennial Fire Protection Inspection Report 05000395/2019012," October 25, 2019 (ADAMS Accession No. ML19301A443).

32 Gatlin, Thomda, D., South Carolina Electric & Gas Company, letter to U.S. Nuclear Regulatory Commission, "Virgil C. Summer Nuclear Station Unit 1, Docket No. 50-395, Operating License No. NPF-12, LAR-06-00055, LAR to Adopt NFPA 805, Response to Request for Additional Information," October 14, 2013 (ADAMS Accession No. ML13289A194).

33 Lippard, George, A., South Carolina Electric & Gas Company, letter to U.S. Nuclear Regulatory Commission, "Virgil C. Summer Nuclear Station Unit 1, Docket No. 50-395, Operating License No. NPF-12, Reply to a Notice of Violation," September 6, 2017 (ADAMS Accession No. ML17249A663).

34 Gatlin, Thomas D., South Carolina Electric and Gas Company, letter to U.S. Nuclear Regulatory Commission, "Virgil C. Summer Nuclear Station Unit 1, Docket No. 50-395, Operating License No. NPF-12, License Amendment Request to Adopt NFPA 805 Response to Request for Additional Information," October 10, 2012 (ADAMS Accession No. ML12297A218).

35 Gatlin, Thomas, South Carolina Electric and Gas Company, letter to U.S. Nuclear Regulatory Commission, "Virgil C. Summer Nuclear Station Unit 1, Docket No. 50-395, Operating License No. NPF-12, License Amendment Request LAR-06-00055, License Amendment Request to Adopt NFPA 805, Additional Information Regarding Response to Request for Additional Information," April 1, 2013 (ADAMS Accession No. ML13092A333).

36 Martin, Robert E., U.S. Nuclear Regulatory Commission, letter to Gatlin, Thomas, D., South Carolina Electric & Gas Company, "Virgil C. Summer Nuclear Station, Unit No. 1 - Request For Additional Information (TAC NO. ME7586)," July 26, 2012 (ADAMS Accession No. ML12202A027).

37 Gatlin, Thomas, D., South Carolina Electric & Gas Company, letter to U.S. Nuclear Regulatory Commission, "Virgil C. Summer Nuclear Station (VCSNS) Unit 1, Docket No. 50-395, Operating License No. NPF-12, License Amendment Request LAR-06-00055, LAR to Adopt NFPA 805 Response to Request For Additional Information," October 14, 2013 (ADAMS Accession No. ML13289A194).

38 Gatlin, Thomas D., South Carolina Electric & Gas Company to U.S. Nuclear Regulatory Commission, "Virgil C. Summer Nuclear Station (VCSNS) Unit 1, Docket No. 50-395, Operating License No. NPF-12, License Amendment Request-LAR-06-00055 License Amendment Request to Adopt NFPA 805 Response to Request for Additional Information,"

February 25, 2014 (ADAMS Accession No. ML14063A455).

39 Dixon, O.W., South Carolina Electric & Gas Co., letter to Denton, H.R., U.S. Nuclear Regulatory Commission, "Report on Appendix R Reanalysis," May 29, 1985 (ADAMS Legacy Library Accession No. 8506050222).

40 Nauman, D.A., South Carolina Electric & Gas Co., letter to Denton, H.R., U.S. Nuclear Regulatory Commission, "Forwards Additional Information Requested in 860402 Meeting, RE 850529 Deviation Requests to Appendix R,Section III.G.2 Separation in Fire Areas AB-1

& AB-25. Description of Additional Deviation to Section III.G.2 in Fire Area IB-25 Also Enclosed.," April 23, 1986 (ADAMS Legacy Library Accession No. 8604280179).

41 Hopkins, Jon, B., U.S. Nuclear Regulatory Commission, letter to Nauman, D.A., South Carolina Electric & Gas Company, "Virgil C. Summer Nuclear Station - Appendix R Reanalysis (TAC No. 57853)," July 27, 1987 (ADAMS Accession No. ML15030A099).

Principal Contributors:

Jay Robinson JS Hyslop Todd Hilsmeier Date: March 6, 2020

ML19305A005 OFFICE DORL/LPL2-1/PM DORL/LPL2-1/LA DRA/DRAFO/ABC OGC/NLO NAME SWilliams KGoldstein MReisi-Fard RAugustus DATE 01/08/2020 01/02/2020 11/21/2019 02/06/2020 OFFICE DORL/LPL2 1/BC DORL/LPL2 1/PM NAME MMarkley SWilliams DATE 03/06/2020 03/06/2020