Text

Issuance of Amendment No. 201, 201, and 201 to Revise Technical Specifications Related to Degraded and Loss of Voltage Relay Modifications
	ML17090A164
Person / Time
Site:	Palo Verde
Issue date:	04/27/2017
From:	Siva Lingam; Plant Licensing Branch IV
To:	Bement R; Arizona Public Service Co
	Lingam S, NRR/DORL/LPLIV, 301-415-1564
References
	CAC MF7569, CAC MF7570, CAC MF7571
	Download: ML17090A164 (40)
	v • d • e

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Robert S. Bement Executive Vice President Nuclear/

Chief Nuclear Officer Mail Station 7602 Arizona Public Service Company P.O. Box 52034 Phoenix, AZ 85072-2034 April 27, 2017

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 -

ISSUANCE OF AMENDMENTS TO REVISE TECHNICAL SPECIFICATIONS RELATED TO DEGRADED AND LOSS OF VOLTAGE RELAY MODIFICATIONS (CAC NOS. MF7569, MF7570, AND MF7571)

Dear Mr. Bement:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 201 to Renewed Facility Operating License No. NPF-41, Amendment No. 201 to Renewed Facility Operating License No. NPF-51, and Amendment No. 201 to Renewed Facility Operating License No. NPF-74 for the Palo Verde Nuclear Generating Station, Units 1, 2, and 3, respectively. The amendments consist of changes to the Technical Specifications (TSs) in response to your application dated April 1, 2016, as supplemented by letters dated July 21, September 9, and October 26, 2016.

The amendments revise the TSs by modifying the requirements regarding the degraded and loss of voltage relays that are planned to be modified to be more aligned with designs generally implemented in the industry. Specifically, the licensing basis for degraded voltage protection will be changed from reliance on a TS initial condition that ensures adequate post-trip voltage support of accident mitigation equipment to crediting automatic actuation of the degraded and loss of voltage relays to ensure proper equipment performance.

A copy of the related Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.

Docket Nos. STN 50-528, STN 50-529, and STN 50-530

Enclosures:

1. Amendment No. 201 to NPF-41

2. Amendment No. 201 to NPF-51

3. Amendment No. 201 to NPF-74

4. Safety Evaluation cc w/encls: Distribution via Listserv Sincerely, Siva P. Lingam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ARIZONA PUBLIC SERVICE COMPANY, ET AL.

DOCKET NO. STN 50-528 PALO VERDE NUCLEAR GENERATING STATION, UNIT 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 201 License No. NPF-41

1.

The Nuclear Regulatory Commission (the Commission) has found that:

A.

The application for amendment by the Arizona Public Service Company (APS or the licensee) on behalf of itself and the Salt River Project Agricultural Improvement and Power District, El Paso Electric Company, Southern California Edison Company, Public Service Company of New Mexico, Los Angeles Department of Water and Power, and Southern California Public Power Authority dated April 1, 2016, as supplemented by letters dated July 21, September 9, and October 26, 2016, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commission's regulations set forth in 10 CFR Chapter I; B.

The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.

There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.

The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.

The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2.

Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C(2) of Renewed Facility Operating License No. NPF-41 is hereby amended to read as follows:

(2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 201, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed operating license. APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.

3.

This license amendment is effective as of the date of issuance and shall be implemented within 120 days of the date of issuance.

Attachment:

Changes to the Renewed Facility Operating License No. NPF-41 and Technical Specifications FOR THE NUCLEAR REGULATORY COMMISSION Robert J. Pascarelli, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: April 27, 2017

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ARIZONA PUBLIC SERVICE COMPANY, ET AL.

DOCKET NO. STN 50-529 PALO VERDE NUCLEAR GENERATING STATION, UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 201 License No. NPF-51

1.

The Nuclear Regulatory Commission (the Commission) has found that:

A.

The application for amendment by the Arizona Public Service Company (APS or the licensee) on behalf of itself and the Salt River Project Agricultural Improvement and Power District, El Paso Electric Company, Southern California Edison Company, Public Service Company of New Mexico, Los Angeles Department of Water and Power, and Southern California Public Power Authority dated April 1, 2016, as supplemented by letters dated July 21, September 9, and October 26, 2016, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commission's regulations set forth in 10 CFR Chapter I; B.

The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.

There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.

The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.

The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2.

Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C(2) of Renewed Facility Operating License No. NPF-51 is hereby amended to read as follows:

(2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 201, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed operating license. APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.

3.

This license amendment is effective as of the date of issuance and shall be implemented within 120 days of the date of issuance.

Attachment:

Changes to the Renewed Facility Operating License No. NPF-51 and Technical Specifications FOR THE NUCLEAR REGULATORY COMMISSION Robert J. Pascarelli, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: Apr i 1 2 7 1 2O1 7

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ARIZONA PUBLIC SERVICE COMPANY, ET AL.

DOCKET NO. STN 50-530 PALO VERDE NUCLEAR GENERATING STATION, UNIT 3 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 201 License No. NPF-74

1.

The Nuclear Regulatory Commission (the Commission) has found that:

A.

The application for amendment by the Arizona Public Service Company (APS or the licensee) on behalf of itself and the Salt River Project Agricultural Improvement and Power District, El Paso Electric Company, Southern California Edison Company, Public Service Company of New Mexico, Los Angeles Department of Water and Power, and Southern California Public Power Authority dated April 1, 2016, as supplemented by letters dated July 21, September 9, and October 26, 2016, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commission's regulations set forth in 1 O CFR Chapter I; B.

The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.

There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.

The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.

The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2.

Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C(2) of Renewed Facility Operating License No. NPF-74 is hereby amended to read as follows:

(2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 201, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed operating license. APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.

3.

This license amendment is effective as of the date of issuance and shall be implemented within 120 days of the date of issuance.

Attachment:

Changes to the Renewed Facility Operating License No. NPF-74 and Technical Specifications FOR THE NUCLEAR REGULATORY COMMISSION Robert J. Pascarelli, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: April 2 7, 2O1 7

ATTACHMENT TO LICENSE AMENDMENT NOS. 201 I 201 I AND 201 TO RENEWED FACILITY OPERATING LICENSE NOS. NPF-41, NPF-51, AND NPF-74 PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 DOCKET NOS. STN 50-528, STN 50-529, AND STN 50-530 Replace the following pages of the Renewed Facility Operating Licenses Nos. NPF-41, NPF-51, and NPF-74, and Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Renewed Facility Operating License No. NPF-41 REMOVE INSERT 5

5 Renewed Facility Operating License No. NPF-51 REMOVE INSERT 6

6 Renewed Facility Operating License No. NPF-74 REMOVE INSERT 4

4 Technical Specifications REMOVE 3.3.7-3 3.8.1-5 INSERT 3.3.7-3 3.3.7-4 3.8.1-5 (1)

Maximum Power Level Arizona Public Service Company (APS) is authorized to operate the facility at reactor core power levels not in excess of 3990 megawatts thermal (100% power), in accordance with the conditions specified herein.

(2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 201, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed operating license.

APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.

(3)

Antitrust Conditions This renewed operating license is subject to the antitrust conditions delineated in Appendix C to this renewed license.

(4)

Operating Staff Experience Requirements Deleted (5)

Post-Fuel-Loading Initial Test Program (Section 14. SER and SSER 2)*

Deleted (6)

Environmental Qualification Deleted (7)

Fire Protection Program APS shall implement and maintain in effect all provisions of the approved fire protection program as described in the Final Safety Analysis Report for the facility, as supplemented and amended, and as approved in the SER through Supplement 11, subject to the following provision:

APS may make changes to the approved fire protection program without prior approval of the Commission only if those changes would not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire.

The parenthetical notation following the title of many license conditions denotes the section of the Safety Evaluation Report and/or its supplements wherein the license condition is discussed.

Renewed Facility Operating License No. NPF-41 Amendment No. 201 (1)

Maximum Power Level Arizona Public Service Company (APS) is authorized to operate the facility at reactor core power levels not in excess of 3990 megawatts thermal (100% power) in accordance with the conditions specified herein.

(2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 201, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed operating license.

APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.

(3)

Antitrust Conditions This renewed operating license is subject to the antitrust conditions delineated in Appendix C to this renewed operating license.

(4)

Operating Staff Experience Requirements (Section 13.1.2. SSER 9)*

Deleted (5)

Initial Test Program (Section 14. SER and SSER 2)

Deleted (6)

Fire Protection Program APS shall implement and maintain in effect all provisions of the approved fire protection program as described in the Final Safety Analysis Report for the facility, as supplemented and amended, and as approved in the SER through Supplement 11, subject to the following provision:

APS may make changes to the approved fire protection program without prior approval of the Commission only if those changes would not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire.

(7) lnservice Inspection Program (Sections 5.2.4 and 6.6. SER and SSER 9)

Deleted

The parenthetical notation following the title of many license conditions denotes the section of the Safety Evaluation Report and/or its supplements wherein the license condition is discussed.

Renewed Facility Operating License No. NPF-51 Amendment No. 201 (4)

Pursuant to the Act and 10 CFR Part 30, 40, and 70, APS to receive, possess, and use in amounts required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components; and (5)

Pursuant to the Act and 10 CFR Parts 30, 40, and 70, APS to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility.

C.

This renewed operating license shall be deemed to contain and is subject to the conditions specified in the Commission's regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1)

Maximum Power Level Arizona Public Service Company (APS) is authorized to operate the facility at reactor core power levels not in excess of 3990 megawatts thermal (100% power), in accordance with the conditions specified herein.

(2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 201, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed operating license.

APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.

(3)

Antitrust Conditions This renewed operating license is subject to the antitrust conditions delineated in Appendix C to this renewed operating license.

(4)

Initial Test Program (Section 14. SER and SSER 2)

Deleted (5)

Additional Conditions The Additional Conditions contained in Appendix D, as revised through Amendment No. 200, are hereby incorporated into this renewed operating license. The licensee shall operate the facility in accordance with the Additional Conditions.

Renewed Facility Operating License No. NPF-74 Amendment No. 201

SURVEILLANCE REQUIREMENTS SURVEILLANCE SR 3.3.7.1 Perform CHANNEL CHECK.

SR 3.3.7.2 Perform CHANNEL FUNCTIONAL TEST.

SR 3.3.7.3

NOTE-------------------

Only applicable for Class lE bus(es) provided with a single stage time delay for the degraded voltage relays and an inverse time delay for the loss of voltage relays.

Perform CHANNEL CALIBRATION with setpoint Allowable Values as follows:

a.

Degraded Voltage Function 2 3697 V and

3786 v Time delay

2 28.6 seconds and

35 seconds: and

b.

Loss of Voltage Function Time delay:

2 10.3 seconds and

12. 6 seconds at 2929. 5 V. and 2 2. 0 seconds and: ::; 2. 4 seconds at O V.

DG - LOVS 3.3.7 FREQUENCY In accordance with the Surveillance Frequency Control Program In accordance with the Surveillance Frequency Control Program In accordance with the Surveillance Frequency Control Program PALO VERDE UNITS 1.2.3 3.3.7-3 AMENDMENT NO. +gg, 201

SURVEILLANCE REQUIREMENTS SR 3.3.7.4 SURVEILLANCE

NOTE-------------------

Only applicable for Class lE bus(es) provided with a two stage time delay for the degraded voltage relays and a fixed time delay for the loss of voltage relays.

Perform CHANNEL CALIBRATION with setpoint Allowable Values as follows:

a.

Degraded Voltage Function ~ 3712 V and

~ 3767 V with a two stage time delay Short stage time delay: ~ 5.5 seconds and~ 8.5 seconds: and Long stage time delay: ~ 31.0.seconds and~ 40.0 seconds: and

b.

Loss of Voltage Function~ 3240 V and

~ 3300 v Time delay:

~ 1.4 seconds and

~ 2. 3 seconds PALO VERDE UNITS 1.2.3 3.3.7-4 DG - LOVS 3.3.7 FREQUENCY In accordance with the Surveillance Frequency Control Program AMENDMENT N0.201

ACTIONS (continued)

CONDITION

NOTE---------

Condition G is not applicable for Class lE busCes) provided with a two stage time delay for the degraded voltage relays and a fixed time delay for the loss of

voltage relays.

G.

One or more required offsite circuit(s) do not meet required ca pa bi l i ty.

H.

Required Action and Associated Completion Time of Condition A.

B. C. D. E. F.

or G not met.

I.

Three or more required AC sources inoperable.

PALO VERDE UNITS 1.2.3 AC Sources - Operating 3.8.1 G.1 OR REQUIRED ACTION Restore required capability of the offsite circuit(s).

NOTE------------

Enter LCD 3.8.1 Condition A or C for required offsite circuit(s) inoperable.

COMPLETION TIME 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months G.2 Transfer the ESF 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months busCes) from the offsite circuit(s) to the EOG(s).

H.l Be in MODE 3.

6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months AND H.2 Be in MODE 5.

36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months I.1 Enter LCO 3.0.3.

Immediately 3.8.1-5 AMENDMENT NO. -+/--:?J,201

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 201 I 201IAND201 TO RENEWED FACILITY OPERATING LICENSE NOS. NPF-41 I NPF-51 I AND NPF-74 ARIZONA PUBLIC SERVICE COMPANY, ET AL.

PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 DOCKET NOS. STN 50-528, STN 50-529, AND STN 50-530

1.0 INTRODUCTION

By letter dated April 1, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16096A337), as supplemented by letters dated July 21, September 9, and October 26, 2016 (ADAMS Accession Nos. ML16203A381, ML16257A544, and ML16300A156, respectively), Arizona Public Service Company (APS, the licensee) submitted a license amendment request (LAR) to revise the Technical Specification (TS) 3.3.7, "Diesel Generator (DG)-Loss of Voltage Start (LOVS)," and TS 3.8.1, "AC [Alternating Current]

Sources - Operating," under TS Section 3.8, "Electrical Power Systems," for Palo Verde Nuclear Generating Station (PVNGS), Units 1, 2, and 3. The LAR revises the TSs by modifying the requirements regarding the degraded and loss of voltage relays that are planned to be modified to be more aligned with designs generally implemented in the industry. Specifically, the licensing basis for degraded voltage protection will be changed from reliance on a TS initial condition that ensures adequate post-trip voltage support of accident mitigation equipment to crediting automatic actuation of the degraded and loss of voltage relays to ensure proper equipment performance.

The supplemental letters dated July 21, September 9, and October 26, 2016, 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) staff's original proposed no significant hazards consideration determination as published in the Federal Registeron May 24, 2016 (81FR32803).

1.1 Background

On July 16, 2009, the NRC staff completed the onsite portion of the Component Design Bases Inspection at PVNGS where the team identified an unresolved item (URI) documented in NRC Inspection Report 05000528; 05000529; and -05000530/2009008 (ADAMS Accession No. ML093240524). This URI identified two aspects related to the degraded voltage protection scheme:

(1) the inadequacy of a time delay of 35 seconds for transfer of safety buses to the onsite power supplies should an actual degraded voltage condition occur with a safety injection actuation signal (SIAS) present, and, (2) the inadequacy of the calculations that demonstrate adequate voltage to safety-related loads during worst case loading conditions (calculations were performed at the degraded voltage relay (DVR) reset voltage rather than at DVR dropout voltage).

The first aspect is the subject of this LAR. In order to address this issue, the licensee is proposing to modify its DVR design to include a second time delay relay, referred to as short stage time delay relay, which will, upon the occurrence of a degraded bus voltage condition and a subsequent SIAS signal, separate the Class 1 E distribution system from the offsite power system in a shorter time. Therefore, the DVR scheme will have a two stage time delay scheme:

the proposed short stage time delay for degraded voltage with an accident (i.e., SIAS) signal present and the existing second long stage time delay to prevent damage to the permanently connected Class 1 E loads.

A subsequent inspection was performed by the NRC in 2014 (ADAMS Accession No. ML14317A308). By this inspection, the second aspect identified in the URI was resolved and closed following the licensee's submittal of revised design calculations that demonstrated adequate equipment performance at the dropout voltage.

This proposed amendment satisfies the APS commitment made to the NRC in APS Letter No. 102-06948-DCM/TNW, dated September 26, 2014 (ADAMS Accession No. ML14276A032),

as modified by Letter No. 102-07144-MLL/TNW, dated November 25, 2015 (ADAMS Accession No. ML15329A228). The licensee's commitment consisted in the development of a plant design change and an associated LAR to shorten the existing degraded voltage protection circuit time delay in TS Surveillance Requirement (SR) 3.3.7.3(a). This design change would result in PVNGS and TS being aligned with designs generally implemented in the industry.

2.0 REGULATORY EVALUATION

The offsite power system consists of seven physically independent circuits, which supply AC power at 525 kiloVolt (kV) to the PVNGS switchyard. From the switchyard, three startup transformers and six 13.8 kV intermediate buses provide preferred power to the AC power distribution system of each unit for startup, normal operation, and safe shutdown of Units 1, 2, and 3. The 13.8 kV buses are arranged in three pairs, each pair feeding only one unit. Each startup transformer is capable of supplying 100 percent of the startup or normally operating loads of one unit simultaneously with the engineered safety feature (ESF) loads associated with two load groups of another unit. The non-Class 1 E AC buses normally are supplied through the unit auxiliary transformer, and the Class 1 E buses normally are supplied through the startup transformers. In the event of loss of supply from the unit auxiliary transformer, an automatic fast transfer of the 13.8 kV buses to the startup transformers is initiated to provide power to the station auxiliary loads. The licensee has performed stability studies to ensure that loss of largest load, a single PVNGS unit trip or the loss of a transmission line will not result in grid instability and loss of preferred power to all three units.

The onsite AC power system includes a Class 1 E and a non-Class 1 E system that distributes AC power at 4.16 kV, 480 Volt (V), and 120 V to all loads. The Class 1 E AC system supplies power to certain selected loads that are not safety-related but are considered important to safety. The standby power supply for each safety-related load group consists of one emergency diesel generator (EOG) complete with its accessories and fuel storage and transfer systems. The EDGs provide AC power for safe plant shutdown in the event of loss of preferred power and for post-accident operation of ESF loads. Each EOG is rated at 5500 kiloWatts (kW) at 0.8 power factor (pf) for continuous operation and 6050 kW at 0.8 pf for 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months out of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

Each 4.16 kV switchgear bus is equipped with a loss-of-voltage relay (LVR) for load shedding, EDG starting, and undervoltage annunciation in the control room. The current configuration of the plant includes four, 4.16 kV safety-related bus induction disc LVRs, and four solid-state DVRs with built-in time delays. The LVRs have a dropout voltage that varies with time, so that they will commence time out if the voltage falls below 78 percent for a long time or below 70 percent for a short time (11.4 seconds or less). The DVRs commence a maximum 35 second time-out when the bus voltage drops to less than 90 percent (nominal) of design.

Recovery of the bus voltage prior to relay timing out will reset the LVRs and DVRs.

The offsite power source is the preferred power source for supporting safe shutdown of the three units. An engineered safety features actuation signal (ESFAS) actuates a solid state sequencer to load the required Class 1 E loads on the respective buses. However, in the event that preferred power is degraded or lost, the DVR or L VR functions to shed Class 1 E loads and to connect the standby power source to the Class 1 E bus. The load sequencer then functions to start the required Class 1 E loads in programmed time increments.

The TSs include limiting conditions for operation (LCOs), SRs, and allowable values for the DVR voltage and time settings. The NRC staff reviewed the proposed TS changes in the LAR against the regulatory requirements and guidance to determine if reasonable assurance exists that systems and components affected by the proposed TS changes will perform their safety functions as required.

2.1 Regulatory Requirements Title 1 O of the Code of Federal Regulations (10 CFR) Part 50, "Domestic Licensing of Production and Utilization Facilities, establishes the fundamental regulatory requirements.

In 10 CFR 50.36, "Technical Specifications, the Commission established its regulatory requirements related to the contents of the TS.

The regulation in 1 O CFR 50.36(a)(1) states:

Each applicant for a license authorizing operation of a production or utilization facility shall include in his application proposed technical specifications in accordance with the requirements of this section. A summary statement of the bases or reasons for such specifications, other than those covering administrative controls, shall also be included in the application, but shall not become part of the technical specifications.

Section 50.36(c)(1 )(ii)(A) of 1 O CFR states, in part:

Where a limiting safety system setting is specified for a variable on which a safety limit has been placed, the setting must be so chosen that automatic protective action will correct the abnormal situation before a safety limit is exceeded. If, during operation, it is determined that the automatic safety system does not function as required, the licensee shall take appropriate action, which may include shutting down the reactor.

The categories of items required to be in the TSs are provided in 1 O CFR 50.36(c). Pursuant to that regulation, TSs are required to include items in the following five specific categories related to station operation: "(1) Safety limits, limiting safety system settings, and limiting control settings; (2) Limiting conditions for operation; (3) Surveillance requirements; (4) Design features; and (5) Administrative controls."

As required by 10 CFR 50.36(c)(2)(i), the TSs will include LCOs, which are the lowest functional capability or performance levels of equipment required for safe operation of the facility. Per 10 CFR 50.36(c)(2)(i), when an LCO of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the TSs until the condition can be met.

In accordance with 10 CFR 50.36(c)(2)(ii)(B), TS LCOs shall include, among other criteria, a process variable, design feature, or operating restriction that is an initial condition of a design-basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.

Section 50.36(c)(3) of 10 CFR states, "Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met."

Section 50.120(b )(ii) of 10 CFR requires that the licensee establish, implement, and maintain a training program that meets the requirements of 10 CFR 50.120, "Training and qualification of nuclear power plant personnel."

Appendix A, "General Design Criteria for Nuclear Power Plants," to 1 O CFR Part 50 establishes the minimum necessary design, fabrication, construction, testing, and performance requirements for structures, systems, and components important to safety; that is, structures, systems, and components that provide reasonable assurance that the facility can be operated without undue risk to the health and safety of the public.

General Design Criterion (GDC) 17, "Electric power systems," Appendix A to 10 CFR Part 50, requires, in part, that nuclear power plants have an onsite and an offsite electric power system to permit the functioning of structures, systems, and components that are important to safety. GDC 17 also states that "[p]rovisions shall be included to minimize the probability of losing electric power from any of the remaining supplies as a result of, or coincident with, the loss of power generated by the nuclear power unit, the loss of power from the transmission network, or the loss of power from the onsite electric power supplies."

GDC 18, "Inspection and testing of electric power systems," Appendix A to 1 O CFR Part 50, states, in part:

Electric power systems important to safety shall be designed to permit appropriate periodic inspection and testing of important areas and features, such as wiring, insulation, connections, and switchboards, to assess the continuity of the systems and the condition of their components.

GDC 19, "Control room," Appendix A to 10 CFR Part 50, states, in part:

A control room shall be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions, including loss-of-coolant accidents....

Equipment at appropriate locations outside the control room shall be provided:

(1) with a design capability for prompt hot shutdown of the reactor, including necessary instrumentation and controls to maintain the unit in a safe condition during hot shutdown, and (2) with a potential capability for subsequent cold shutdown of the reactor through the use of suitable procedures.

The PVNGS Updated Final Safety Evaluation Report (UFSAR), Section 3.1, Conformance with NRC General Design Criteria," states, in part: "PVNGS design is in compliance with the NRC General Design Criteria, unless specifically stated otherwise under individual criteria."

PVNGS UFSAR Section 3.1.9, Criterion 13, "Instrumentation and Control," requires that:

Instrumentation and control shall be provided to monitor variables and systems over their anticipated ranges for normal operation, for anticipated operational occurrences, and for accident conditions as appropriate to assure adequate safety, including those variables and systems that can affect the fission process, the integrity of the reactor core, the reactor coolant pressure boundary, and the containment and its associated systems. Appropriate controls shall be provided to maintain these variables and systems within prescribed operating ranges.

PVNGS UFSAR Section 3.1.16, Criterion 20, "Protection System Functions," requires that:

The protection system shall be designed (1) to initiate automatically the operation of appropriate systems including the reactivity control systems, to assure that specified acceptable fuel design limits are not exceeded as a result of anticipated operational occurrences and (2) to sense accident conditions and to initiate the operation of systems and components important to safety.

The UFSAR, Section 8.3.1.1.3.13.B, "Electric Circuit Protection Systems," states, in part, that the DVRs satisfy the following criteria:

1.

The selection of voltage and time setpoints was determined from an analysis of the voltage requirements of the safety-related loads at all onsite system distribution levels.

2.

Coincident (two-out-of-four) logic is used to preclude the spurious trip of the offsite source.

3.

The time delays are such that:

The selected time delay minimizes the ability of short duration disturbances to reduce the availability of the offsite power source(s).

The allowed time duration of a degraded voltage condition at all distribution system levels does not result in failure of safety systems or components.

4.

The voltage sensors will automatically initiate the disconnection of offsite power sources whenever the voltage setpoint and time delay limits have been exceeded.

5.

The voltage sensors are designed to satisfy the applicable requirements of Institute of IEEE [Institute of Electrical and Electronics Engineers]

Standard 279-1971, Criteria for Protection Systems for Nuclear Power Generating Stations.

2.2 Regulatory Guidance NUREG-0711, Revision 3, "Human Factors Engineering Program Review Model," dated November 2012 (ADAMS Accession No. ML12324A013), provides the methodology for the NRC staff's review of human factors engineering programs.

NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water] Edition," Section 13.2.1, Revision 4, "Reactor Operator Requalification Program; Reactor Operator Training," dated August 2016 (ADAMS Accession No. ML15006A035), provides the NRC staff's guidance for the reviewing the adequacy of operator training.

NUREG-0800, Section 13.5.2.1, Revision 2, "Operating and Emergency Operating Procedures,"

March 2007 (ADAMS Accession No. ML070100635), provides the methodology for the NRC staff's review of operating procedures that will be used by the operating organization to ensure that routine operating, off-normal, and emergency activities are conducted in a safe manner.

NUREG-0800, Section 18, Revision 3, "Human Factors Engineering," dated December 2016 (ADAMS Accession No. ML16125A114), provides the NRC staff's guidance for the review of human performance for the applicants.

NUREG-0800, Branch Technical Position (BTP) 8-6, "Adequacy of Station Electric Distribution System Voltages," Revision 3 (ADAMS Accession No. ML070710478), outlines the purpose of the DVRs to protect Class 1 E safety-related buses from sustained degraded voltage conditions on the offsite power system under accident and non-accident conditions. Specifically, BTP 8-6, Section 8.1, and subparagraphs (a) and (b), states that the second level of undervoltage protection should include two separate time delays:

(i)

The first time delay should be long enough to establish the existence of a sustained degraded voltage condition (i.e., something longer than a motor-starting transient). Following this delay, an alarm in the control room should alert the operator to the degraded condition. The subsequent occurrence of a safety injection actuation signal (SIAS) should immediately separate the Class 1 E distribution system from the offsite power system. In addition, the degraded voltage relay logic should appropriately function during the occurrence of an SIAS followed by a degraded voltage condition, and (ii)

The second time delay should be limited to prevent damage to the permanently connected Class 1 E loads. Following this delay, if the operator has failed to restore adequate voltages, the Class 1 E distribution system should be automatically separated from the offsite power system.

The bases and justification for such an action must be provided in support of the actual delay chosen.

The NRC staff's guidance for review of TSs is in Section 16, "Technical Specifications," of NUREG-0800, Revision 3, dated March 2010 (ADAMS Accession No. ML100351425). As described therein, as part of the regulatory standardization effort, the NRC staff has prepared Standard Technical Specifications (STS) for each of the LWR nuclear designs. NUREG-1431 contains the STS for Westinghouse plants.

NUREG-1764, Revision 1, "Guidance for the Review of Changes to Human Actions," dated September 2007 (ADAMS Accession No. ML072640413), provides guidance for NRC staff for the level of review for LARs.

Regulatory Guide (RG) 1.105, Revision 3, "Setpoints for Safety-Related Instrumentation," dated December 1999 (ADAMS Accession No. ML993560062) describes a method that the NRC staff finds acceptable for use in complying with the NRC's regulations for ensuring that setpoints for safety-related instrumentation are initially within, and will remain within, the TS limits. RG 1.105 endorses Part I of Instrument Society of America S67.04-1994, "Setpoints for Nuclear Safety-Related Instrumentation," subject to NRC staff clarifications.

NRC Information Notice (IN) 95-05, "Undervoltage Protection Relay Settings Out of Tolerance Due to Test Equipment Harmonics," dated January 20, 1995 (ADAMS Accession No. ML031060397).

NRC IN 95-37: "Inadequate Offsite Power System Voltages During Design-Basis Events," dated September 7, 1995 (ADAMS Accession No. ML031060285).

In Regulatory Issue Summary (RIS) 2006-17, "NRC Staff Position on the Requirements of 1 O CFR 50.36, 'Technical Specifications,' Regarding Limiting Safety System Settings During Periodic Testing and Calibration of Instrument Channels," dated August 24, 2006 (ADAMS Accession No. ML051810077), the NRC staff addresses requirements on limiting safety system settings that are assessed during the periodic testing and calibration of instrumentation.

RIS 2011-12, Revision 1, "Adequacy of Station Electric Distribution System Voltages (ADAMS Accession No. ML113050583).

Applicable requirements of IEEE Standard 279-1971, "Criteria for Protection Systems for Nuclear Power Generating Stations."

3.0 TECHNICAL EVALUATION

The NRC staff has reviewed the licensee's regulatory and technical analyses in support of its proposed license amendment, which is described in the Enclosure of the LAR dated April 1, 2016.

3.1 Proposed TS Changes

The proposed changes include the following TS revisions:

1.

Revise TS 3.3.7, "Diesel Generator (DG) - Loss of Voltage Start (LOVS)":

a.

Revise SR 3.3.7.3 for the unmodified Class 1 E bus( es):

i.

Add a new NOTE indicating the SR is only applicable to Class 1 E bus( es) with a single stage time delay for the DVR and an inverse time delay for the LVRs.

b.

Add a NOTE to new SR 3.3.7.4 indicating the SR is only applicable to Class 1 E bus( es) that have been modified to include a two stage time delay for the DVRs and a fixed time delay for the LVRs.

c.

Add new SR 3.3.7.4.a for the modified bus(es) to:

i.

Provide new TS allowable values for the degraded voltage function, ii.

Provide a short stage time delay for the DVRs when a SIAS is present, and iii.

Provide a long stage time delay for the DVRs when a SIAS is not present.

d.

Add new SR 3.3.7.4.b for the modified bus( es) to:

i.

Provide new TS allowable values for the loss of voltage function ii.

Provide a fixed time delay relay for the LVRs

2.

Revise TS 3.8.1, "AC Sources - Operating" under TS Section 3.8, "Electrical Power Systems":

a.

Add a new NOTE to the ACTIONS table for Condition G indicating Condition G is not applicable for Class 1 E bus( es) provided with a two stage time delay for the DVRs and a fixed time delay for the L VRs.

The licensee stated that the installation of the modification requires a refueling outage and that it plans to implement the modification in upcoming refueling outages. The licensee anticipates that completion of the modification will require approximately 3 years. Therefore, it is necessary that the TS be flexible to address both pre-modification and post-modification configurations.

The proposed amendment adds new SR 3.3.7.4 with the following trip setpoint allowable values:

a.

Degraded Voltage Function: Between 3712 V and 3767 V with a two stage time delay.

Short stage time delay: 5.5 seconds to 8.5 seconds; Long stage time delay: 31 seconds to 40 seconds

b.

Loss of Voltage Function: Between 3240 V and 3300 V Time delay: 1.4 seconds to 2.3 seconds The proposed amendment will retain the setpoint allowable values for existing DG undervoltage relays in SR 3.3.7.3 and add notes to define applicability because both modified and unmodified configurations will need to be addressed by plant technical specifications until all plant configurations have been updated to the new configuration.

The proposed change has been submitted to correct non-conservative values in the TS and to meet a commitment made by the licensee to modify the degraded voltage protection designs to be more aligned with designs generally implemented in the industry (ADAMS Accession Nos. ML14276A032, and ML15329A228). These parameters are modified to ensure the trip of the safety-related AC bus will occur at a voltage at or above the minimum voltage necessary to operate applicable safety-related loads.

3.2 Proposed System Description The licensee's current design includes a long range time delay relay only. BTP 8-6 states that the DVRs protect Class 1 E safety-related buses from sustained degraded voltage conditions on the offsite power system under accident and non-accident conditions. PVNGS's current design provides a long range time delay only and administrative controls for managing degraded voltage conditions. In order to provide protection under accident conditions, as stated in BTP 8-6, and provide prompt response on the occurrence of a SIAS signal, the DVR design should include a short range time delay that should be long enough to establish the existence of a sustained degraded voltage condition and will separate the Class 1 E buses upon the subsequent occurrence of a SIAS.

The current operating procedures at PVNGS rely on administrative controls to improve Class 1 E bus voltages when degraded voltage conditions are observed. Specifically, TS 3.8.1, Condition G, allows 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months to restore offsite power to operable status in the event of degraded voltage conditions. The proposed change will provide reasonable assurance for adequate post-trip voltage support for accident mitigation equipment and rely on automatic actuation of the DVRs and L VRs to ensure proper equipment performance.

3.2.1 Degraded Voltage Relays The offsite power source is the preferred power source for supporting safe shutdown of the three units. In the event of an accident, an ESFAS actuates a solid state sequencer to load the required Class 1 E loads on the respective buses connected to the startup transformers.

However, if the preferred power source is degraded or lost, the DVR and/or LVRs function to shed Class 1 E loads and connect the standby power source to the Class 1 E bus. The load sequencer then functions to start the required Class 1 E loads in programmed time increments as determined in the accident analysis. The nominal setting of the DVRs is 90 percent of the nominal bus voltage. Neither the alarm function in the control room nor the coincidence logic for the actuation of the existing DVRs and LVRs will be affected by the proposed modification. The existing DVR design provides a separate relay to support the degraded voltage alarm function in the control room. The licensee is proposing a new DVR scheme with the same voltage setpoint of 90 percent of nominal bus voltage but with a short stage time delay when an accident signal (SIAS) is present.

3.2.1.1 Degraded Voltage Relay Short Stage Time Delay The proposed short stage time delay for the DVRs that is in effect concurrent with a SIAS, has analytical time limits of 5.0 and 9.0 seconds. The corresponding allowable values are 5.5 and 8.5 seconds. The time delay is long enough to establish the existence of a sustained degraded voltage condition (i.e., something longer than a motor-starting transient) and consistent with BTP 8-6, Section 8.1, subparagraph (b)(i). The lower analytical limit ensures that the DVR will not trip due to voltage dips during SIAS load starts, which are 5 seconds apart. The corresponding allowable value for the lower analytical limit is 5.5 seconds.

The short stage time delay upper limit is based on ensuring the DVR trip will result in actuation of the balance of plant engineered safety features actuation system (BOP-ESFAS) sequencer loss of offsite power (LOOP) response within the time evaluated in safety analyses for LOOP/SIAS events. Safety analyses assume the EOG is ready to receive loads in 10 seconds or less after a SIAS signal. Allowing for an intentional 1 second delay from the BOP-ESFAS sequencer load shed pulse, results in an analytical limit of 9.0 seconds. The corresponding allowable value is 8.5 seconds. Therefore, the subsequent connection of the EDG to the safety-related buses and initiation of load steps will be in accordance with the assumptions made in safety analyses. In view of the relatively short duration of degraded voltage conditions while the DVR is timing out, it is expected that equipment that may have started or was operating and is required to operate for an accident response will not be damaged and the protective relays will not trip. The equipment should be available to automatically start, when sequenced, following separation from the offsite source by the DVR actuation.

3.2.1.2 Degraded Voltage Relay Long Stage Time Delay At PVNGS, large reactor coolant pump (RCP) motors are connected on the primary voltage side (i.e., 13.8 kV non-Class 1 E winding) of the ESF transformers that provide the preferred off site power to the 4.16 kV Class 1 E buses. The licensee has stated in its LAA that "the start of an RCP motor momentarily lowers bus voltage (for approximately 18 seconds) such that the planned short stage time delay of approximately 7 seconds could cause inappropriate separation of the Class 1 E bus from the preferred offsite power sources." Hence, the licensee has retained the long stage DVRs. The licensee has performed an analysis of the operation of electrical loads with bus voltage degraded below the DVR dropout with no SIAS present. The analysis was used to confirm the upper and lower analytical limits for the voltage setpoint of the L VRs. The limits ensure that the DVR and L VA settings will avoid unnecessary trips while protecting equipment from damage and also ensuring the plant equipment can carry out automatic actions, other than a SIAS, when degraded voltage conditions are present on the safety-related buses.

The long stage time delay for the OVRs has been analyzed to provide appropriate protection for time analytical limits of 27.4 and 44 seconds. The corresponding allowable values are 31.0 seconds and 40 seconds. The lower limit is based on ensuring the OVR will not trip due to voltage dips during RCP motor starts at the lower end of the switchyard voltage normal operating band. The upper limit is based on not exposing equipment to degraded voltage for longer than manufacturer recommended times and also ensuring no overcurrent trip lockouts occur on running equipment. The licensee has stated that equipment running with voltages below the OVR dropout but just above the LVR dropout will not trip on overcurrent before the maximum long stage time delay limit of 44 seconds.

In a manner similar to the short stage timer analysis, there is a need to ensure that while the DVR long stage timer is running, that equipment is not damaged nor does its protective relay trip. The long stage timer analysis evaluates voltages below OVR dropout. More specifically, the long stage timer calculation evaluates equipment powered by Class 1 E buses that may be subjected to a degraded voltage during a non-SIAS conditions. The analysis demonstrates that equipment required to respond to automatically actuated signals such as an Auxiliary Feedwater Actuation Signal (AFAS) will not be damaged and will be able to start when sequenced, following separation from the offsite source by the OVRs.

The licensee evaluated the operation of equipment at the whole range of voltages between the DVR dropout point and the LVR actuation point. The long stage timer analysis shows that no permanently connected motors will stall, no contactors will drop out, and no overcurrent trips will occur during the long stage delay time period of up to the analyzed limit of 44 seconds.

Necessary equipment will be available when sequenced to the EOG and the conditions of BTP 8-6, Section B.1, subparagraph (b)(ii) are met for the long stage time delay (i.e., permanently connected Class 1 E loads are not damaged and are available when sequenced to onsite power).

The licensee has stated that the largest motor at each load step was evaluated and shown to be able to start for voltages below the DVR dropout but above a point where the AFAS actuation would cause LVR actuation. If the degraded voltage is below a value where AFAS initiated equipment would successfully operate, the voltage dip from starting the Auxiliary Feedwater Pump (AFP)-B motor will cause an LVR actuation, resulting in a LOOP signal and initiating the applicable BOP-ESFAS sequence onto the EOG.

3.2.1.3 Loss of Voltage Relay The licensee determined that it would be advantageous to replace the existing mechanical inverse time delay LVRs with solid state fixed time delay relays. The proposed new replacement LVRs, with a fixed time delay, will have limits and corresponding allowable values based on the following criteria:

1.

The time delay must be long enough to not separate from offsite power during fast recovering grid disturbances such as a lightning strike. The analyzed limit for this criterion is 1.2 seconds and the corresponding allowable value is 1.4 seconds.

2.

The time delay must be short enough to respond to a total loss of voltage without exposing the equipment to a very low voltage. It must also be less than the minimum safe times determined for the various equipment analyzed in the supporting calculations. The analyzed limit for this criterion is 2.5 seconds and the corresponding allowable value is 2.3 seconds.

3.

The voltage must be below the minimum related to a RCP motor start, to ensure that the L VR does not cause an inappropriate separation from offsite power during that motor start. The analyzed limit is 3314 volts with a corresponding allowable value of 3300 volts.

4.

The voltage must be above the minimum safe voltages determined for the various equipment analyzed in the supporting calculations. The analyzed limit for this criterion is 3220 volts and the corresponding allowable value is 3240 volts.

The new replacement LVRs are definite-time devices and will respond within fixed times when actuated due to low voltage conditions. The DVR and L VR time delay analysis and supporting calculations determined limits to ensure that:

1.

The capability of the equipment required to respond to a SIAS to automatically restart after the DVR short stage time delay with a bus voltage below the DVR lower voltage analytical limit, and

2.

The capability of permanently connected Class 1 E equipment to operate with voltage just above the upper LVR dropout limit for the DVR long stage time delay.

The calculations provide the limits needed to ensure the adequacy of the LVR dropout setpoint to protect equipment from damage and to ensure equipment does not lock out requiring a manual reset of overcurrent devices. The time delay of the LVR dropout is long enough to allow for switchyard voltage transients caused by lightning strikes, clearance of grounds or other faults, while being short enough to minimize time equipment is offline due to the loss of voltage.

The upper limit on the LVR dropout setpoint is coordinated with the minimum voltage expected during operation by ensuring it would not actuate due to the voltage dip caused by a RCP motor start in the lower end of the switchyard voltage normal operating band.

This LAR is intended to provide a more effective resolution to aspect time delay of the PVNGS degraded voltage protection scheme by introducing a two stage time delay circuit, which acts in two different ways depending on the actuation state of a SIAS input.

When a SIAS signal is present, a short delay time function is activated under degraded voltage conditions causing an early protection signal actuation and transfer to emergency power sources. When the SIAS signal is not active, a long delay time function is activated to permit RCP motor starts without causing separation of 1 E buses from preferred power sources.

Existing mechanical inverse time delay relays are being replaced with solid state fixed time delay relays.

Once this new scheme is implemented, the currently credited preventive administrative controls designated in TS 3.8.1, Condition G will no longer be required. This is currently a 1-hour required action completion time. As such, a subsequent license amendment will be processed to remove TS 3.8.1, Condition G, as well as SR 3.3.7.3, once plant modifications are complete.

3.4 Staff Evaluation 3.4.1 Evaluation of Electrical Changes The NRC staff reviewed an overview of design information and the corresponding technical specification proposed changes related to the DVR short range time delay provided in the LAR.

The scope of this section of the safety evaluation (SE) was limited to the summary of:

I.

technical descriptions of the planned modification of the DVRs and LVRs, and II.

the underlying technical basis for the scheme change.

During its review, the NRC staff provided the licensee a request for additional information (RAI) addressing questions concerning information submitted by the licensee, and the staff provided generic communications, such as, RIS 2012-11, Revision 1.

Section 2 of the LAR states that the SR 3.3.7.3 would add a note indicating that the SR would only be applicable to Class 1 E bus( es) that have not been modified to include a two stage time delay for the DVRs (therefore, its DVRs have a single stage time delay) and an inverse time delay for the LVRs. The NRC staff needed clarification on Class 1 E buses that would not have two stage time delays after the modifications were implemented and clarification on each relay's setpoint and protective function. The NRC staff requested the licensee to provide a tabulated summary of the DVR setpoints (single stage and two stage) and the protective function performed by each relay for the postulated degraded conditions. The staff also requested the licensee to provide a similar summary for the L VRs.

In a letter dated October 26, 2016, the licensee confirmed that it plans to perform the modification of the DVRs and L VRs in a staged manner over successive refueling outages and that during the interim operating cycle, some unmodified Class 1 E buses will have single stage DVRs only. The licensee also provided the following tables displaying the protective functions and allowable values for the DVRs and the LVRs.

Existina Sinale Sta{.le DVR Protective Function Allowable Value 4160 Volt Essential System Bus 3697 V ~Voltage ~3786 V Undervoltage - Degraded Voltage 28.6 sec ~time ~35 sec Proposed Two Stage DVR Protective Function Allowable Value 4160 Volt Essential System Bus 3712 V ~Voltage ~3767 V Undervoltage - Degraded Voltage (concurrent with SIAS) 5.5 sec ~time ~8.5 sec 4160 Volt Essential System Bus 3712 V ~Voltage ~3767 V Undervoltage - Degraded Voltage (no SIAS) 31 sec ~time< 40 sec Existina Inverse Time Delav LVR Protective Function Allowable Value 4160 Volt Essential System Bus 2929.5 v Undervoltage - Loss of Voltage 10.3 sec ~time~ 12.6 sec o Volts 2.0 sec ~time ~2.4 sec Proposed Fixed Time Delav LVR Protective Function Allowable Value 4160 Volt Essential System Bus 3240 V ~Voltage ~3300 V Undervoltage - Loss of Voltage 1.4 sec ~time ~2.3 sec The licensee also clarified that both the new DVRs and LVRs will be ABB Type 27N, model 411T4375-HF-L-DP; both relays sense the voltage in the same manner but will have different voltage and time setpoints. The licensee also provided diagrams to display the existing configuration and the configuration post-modification.

In summary, the licensee's response to Electrical Engineering Branch (EEEB) RAl-1 by letter dated October 26, 2017, clarified the staged implementation of protective relay modifications, function of the DVRs and the LVR, provided the setpoints for each relay, and provided diagrams to display the existing configuration and the configuration post-modification displaying the sequential replacement of all the DVRs and LVRs with the new ABB model. Furthermore, the final configuration of the plant will include a second separate short stage timer that will respond to a degraded voltage condition concurrent with a SIAS consistent with BTP 8-6, Revision 3, subparagraph (b)(i) for all Class 1 E buses. Therefore, the NRC staff finds this response acceptable.

Section 3.1.1, "Degraded Voltage Relay Short Stage Time Delay," of the licensee's LAR, states, in part:

"The new short stage time delay for the DVRs, that is in effect when a SIAS also occurs, has analytical limits of 5.0 and 9.0 seconds. The corresponding allowable values are 5.5 and 8.5 seconds.

The time delay is long enough to establish the existence of a sustained degraded voltage condition (i.e., something longer than a motor-starting transient), as described in BTP 8-6, Section B.1, subparagraph (b)(i). The lower analytical limit is based on ensuring the DVR will not trip due to voltage dips during SIAS load starts, which are 5 seconds apart. For an offsite source that is degraded but still allows loads to start, motors will accelerate and voltage will recover above DVR dropout prior to the next sequence step. The corresponding allowable value for the lower analytical limit is 5.5 seconds."

The NRC staff understood that motor start, motor stall and motor withstand capability for all safety-related motors was evaluated at the analytical limits for DVR dropout voltage of 3690 V.

The DVR drops out (but not actuate until the allowable elapsed time) during a motor start when the bus voltage will drops below 3690 V. The general assumption is that grid voltage may recover and allow the 4160 V safety bus voltage to improve to a value above the DVR pickup voltage (3805 V) to reset the relay prior to the next load sequencing. However, from an analytical perspective, the grid voltage is conservatively maintained at degraded conditions to demonstrate the capability of large motors to successfully start and run under degraded voltage conditions. Therefore, the NRC staff requested the licensee to confirm that this methodology was used for the PVNGS DVR analyses.

In a letter dated October 26, 2016, the licensee described the methodology used to determine the analytical limits of the DVR confirming that the motor starting evaluations were performed with the safety bus artificially set at the DVR dropout value of 3690 V prior to motor start. The licensee also stated that this analysis is documented in calculation 13-EC-MA-0643, Degraded Voltage Result I Component Review. This calculation was reviewed during the closeout of the NRC URI described in Section 2.2 of the LAR and documented in an NRC inspection report dated November 12, 2014 (ADAMS Accession No. ML14317A308). The licensee also clarified that for the DVR short stage timer, the "voltage will recover above DVR reset prior to the next sequence step" since it is more precise to use the term 'reset' as compared to the term 'dropout' because the electrical design philosophy assumes that if the Class 1 E bus voltage does not recover above the reset voltage before the start of each load group, the offsite source may not be sufficiently capable, therefore, automatic transfer to the onsite source is appropriate.

In summary, the licensee's response to EEEB RAl-2 by letter dated October 26, 2016, has confirmed that the methodology used to determine the analytical limits of the DVR had the motor starting evaluations performed with the safety bus artificially set at the DVR dropout value of 3690 V, thereby ensuring the capability of large motors to successfully start and run under degraded voltage conditions. Since this response is consistent with BTP 8-6 as it pertains to the assumptions employed in calculation of the analytical limits ensuring adequate voltage during the starting and running of motors, the NRC staff finds this response acceptable.

The NRC staff reviewed scenarios where the voltage decreases below the DVR/LVR dropout setting but does not recover above the DVR/LVR reset setting prior to the DVR/LVR time delay limit being exceeded (i.e., DVR/LVR actuates and times out causing automatic disconnection of offsite power and automatic transfer to the onsite power supply). The NRC staff requested the licensee to confirm if a range of initial bus voltages above the DVR dropout voltage was considered to envelope the limiting cases. The NRC staff also asked the licensee to confirm whether the safety-related buses are protected in the operating band between the lower limit of the DVR and the upper limit of the LVR, and to explain the methodology used to address this issue.

In a letter dated October 26, 2016, the licensee stated that the analysis confirmed that:

I.

The safety-related buses are protected in the operating band between the lower limit of the DVR and the upper limit of the L VR.

II.

The safety-related loads will be able to perform their intended design functions under accident conditions with the offsite power supply at the minimum allowable (operable) voltage and capacity.

The licensee also clarified that there was ample margin between the lower limit of the DVR and the upper limit of the LVR; the lower allowable value for the DVR is 3712 V and the upper allowable value of the LVR is 3300 V. The licensee documented its analysis in calculations 13-EC-PB-0205, Revision 0, Degraded Voltage Relay Short Stage Timer Analysis, and 13-EC-PB-0206, Revision 0, Degraded Voltage Relay Long Stage Timer Analysis; these analyses also confirm that DVR and LVR protection and coordination had also been performed.

The licensee's position is consistent with BTP 8-6 as it pertains to the voltage levels at the safety-related buses being optimized for the minimum load conditions that are expected throughout the anticipated range of voltage variations of the offsite power sources. Therefore, the NRC staff finds this response acceptable.

The NRC staff also requested the licensee to confirm if the DVRs and LVRs are bypassed during load sequencing on the onsite EDGs. In a letter dated October 26, 2016, the licensee confirmed that the existing load sequencer will allow ESF loads to sequence given a 60-second

'off-delay' integrated in its design; each sequence is completed within approximately 30 seconds. The licensee also clarified that the proposed modifications in the LAR will not affect this existing design feature. Since the licensee confirmed DVRs will not prevent load sequencing on the EDGs and allow the ESF loads to perform their safety functions, the staff finds this response acceptable.

The NRC staff also requested the licensee to confirm if the proposed new relays have harmonic filters to preclude spurious actuations due to bus harmonics. In a letter dated October 26, 2016, the licensee confirmed that all the proposed DVRs and LVRs have harmonic filters. The modification will use ABB undervoltage relay model number 411T4375-HF-L-DP (the letters 'HF' in the model number indicates "Harmonic Filter). The staff finds this response acceptable since it addresses the issue discussed in NRC IN 95-05 in regards to the potential occurrence of test equipment harmonics that could result in undervoltage relay actuation settings that are out of tolerance.

3.4.2 Evaluation of Setpoint Changes The components used to implement the PVNGS degraded voltage protection scheme are listed below. In this section of the SE, the NRC staff evaluated each of these components and the assigned setpoints for them to determine if they would provide an adequate means of implementing the proposed undervoltage protection scheme.

Current Transformers Degraded Voltage Relay including DVR Short Stage Time Delay Degraded Voltage Relay Long Stage Time Delay Loss of Voltage Relay including LVR Time Delay The PVNGS 4.16 kV Class 1 E buses are provided with two types of undervoltage protection; one is a two stage DVR scheme with two different time delay settings and the other is a LVR.

Each of these undervoltage protection functions receives input from three potential transformers (PT) connected to the applicable 1 E buses and is actuated by a two-out-of-three trip coincidence logic.

3.4.2.1 DVR Protection Under conditions in which a SIAS is present, the DVR relays initiate a short time delay function to transfer the bus to its emergency power source. The delay time for this function is shorter than the existing delay times associated with a degraded voltage without a complete loss of bus voltage.

The short delay function is performed by a device hereafter referred to as a as a 27N relay, which performs the dual functions of detecting a low voltage input signal and of delaying its output actuation by a fixed amount of time after the low voltage condition is received. As such, there are two settings assigned to this component. The first is the voltage actuation setpoint and the second is the time delay setting. The allowable values for each of these settings is provided in the proposed TS markup in Attachment 1 of the LAR.

Under conditions in which the SIAS is not present, the DVR relays initiate a long time delay function for transferring the bus to its emergency power source. This longer time delay is accomplished by a separate time delay Agastat component and is accomplished in conjunction with the actuation of the previously discussed 27N relay. The delay time for this function is slightly longer than the previous delay times associated with a degraded voltage without a complete loss of bus voltage, however under accident conditions, the short delay function will override the long delay function to accomplish the faster bus transfer that will assure continued availability of critical electrical bus loads during accident scenarios.

The Agastat component of the long time delay DVR function has only one setting of delay time.

It does not determine the low voltage level of actuation. Instead it shares the low voltage actuation signal from the 27N relay and provides an additive delay time for the bus transfer function. Because of this arrangement, the effective delay time for the long time delay DVR is the sum of the 27N relay delay time and the agastat delay time. The allowable value for this combined setting is provided in the proposed TS markup in Attachment 1 of the LAR.

3.4.2.2 Setting Requirements The trip setpoints and allowable values for the proposed degraded voltage protection scheme are based on analytical limits, which establish allowable minimum dropout and maximum reset values for the DVRs. These established limits use calibration tolerances, instrumentation uncertainties and instrument drift factors to determine the minimum dropout voltage levels necessary to ensure protection during sustained degraded voltage conditions.

To provide an additional measure of protection the DVRs are nominally set to a value that is higher than the calculated minimum setpoint. The PVNGS DVRs are set to a value that is 90 percent of the nominal bus voltage which is 3744 volts alternating current. of the LAR provides a technical description of the proposed modification of degraded and loss of voltage relays. This discussion includes a section that describes the process for determining allowable values for the DVRs. The NRC staff reviewed this description and determined that additional information on how setpoint calculations were performed would be necessary to determine compliance with regulatory requirements.

To address this matter, APS made the setpoint calculation available for review during the NRC audit conducted on August 26, 2016 (ADAMS Accession No. ML16251A245). During this audit, APS staff provided an overview of the calculation and discussed the methodology used in the derivation of the TS SR allowable values.

The NRC staff reviewed Calculation 13-EC-PB-0202, "4160 V Degraded Voltage Relay (DVR) and Loss of Voltage Relay (LoVR) Setpoint & Calibration Calculation, Revision 5," to confirm that the proposed allowable values in SR 3.3.7.4 conform to the criteria of RG 1.105, Revision 3.

3.4.2.3 Setpoint Uncertainty Factors of the LAR provides a list of uncertainty factors considered for setpoint determination. The NRC staff confirmed these uncertainty factors were being adequately considered and sufficient justifications were provided for exclusion of terms that were not used for determination of total loop uncertainty.

3.4.2.4 Undervoltage Relay Setpoint Calculation 13-EC-PB-202 provides the following values for establishing new settings for the undervoltage relays. The correlation between BUS voltage and relay setting voltages is based on the PT turns ratio of 34.916. This calculation was reviewed during the NRC's regulatory audit on August 26, 2016 (ADAMS Accession No. ML16230A604). The results of this calculation were also summarized in Attachment 4 of the LAR.

Total Loop Uncertainty (TLU) = +42.7/-33 V Nominal Trip Setpoint (NTSP) = 107.23 V, (3744 V BUS)

Analytical Limit (AL) between 105.68 V and 108.98 V. (3690 V to 3805 V BUS)

Allowable Value between 106.31 V and 107.89 V. (3712 V to 3767 V BUS)

These settings establish a margin of 22 V between the technical specification allowable value (TSAV) voltage and the established lower AL, which provides a 40.7 percent additional margin to the AL. The margin at the upper end is 38 V, which provides a 62.3 percent margin to the upper AL. These margins provide reasonable assurance the ALs will not be exceeded during plant operations. The NRC staff finds this setting is acceptable because it provides adequate upper and lower margins with consideration of the established TLU instrument uncertainties.

In Section 5.11.2, 'Work Order History for ABB Type 27N Relays," of Attachment 4 to the LAR, the licensee provided a work order history evaluation and a summary of statistical data as evidence of inservice instrument performance. The field data used to determine the statistics presented in the LAR, was also reviewed by the NRC staff during the regulatory audit. The staff used the resulting statistical data as a basis for its determination of compliance with RG 1.105 criteria for instrument reliability and confidence.

Uncertainty factors used in calculating TLU, as-found tolerances, and as-left tolerances are either vendor provided or supported by equipment performance test results. The NRC staff confirmed that sufficient margin exists in both the high and low voltage directions with consideration for the calculated instrument uncertainties (i.e., TLU). Therefore, the undervoltage relays have demonstrated performance of 95/95 reliability and confidence levels as specified in RG 1.105. Furthermore, continued surveillance testing will monitor relay performance such that degraded performance or reduced reliability of the undervoltage relays will be identified and addressed under the licensees corrective action programs. The NRC staff determined the uncertainty factors used by the licensee in the undervoltage relay setpoint calculations is acceptable.

3.4.2.5 L VR Setpoint The L VR relays are similar in design to the undervoltage relay described above. They are the same ABB Type 27N and model but have different voltage and time delay settings. Calculation 13-EC-PB-202 provides the following values for establishing new settings for the LVR relays.

(TLU = +42.7/-33 V NTSP = 93.65 V, (3270 V BUS)

AL between 92.22 V and 94.91 V. (3220 V to 3314 V BUS)

AV between 92.79 V and 94.51 V. (3240 V to 3300 V BUS)

These settings establish a margin of 20 V between the TSAV voltage and the established lower AL, which provides a 40.0 percent additional margin to the AL. The margin at the upper end is 14 V, which provides a 31.82 percent margin to the upper AL. These margins provide reasonable assurance the ALs will not be exceeded during plant operations. The NRG staff finds this setting is acceptable because it provides adequate upper and lower margins with consideration of the established TLU instrument uncertainties.

The NRG staff confirmed that sufficient margin exists in both the high and low voltage directions with consideration for the calculated instrument uncertainties (i.e., TLU). Therefore, the LVR relays have demonstrated performance of 95/95 reliability and confidence levels as specified in RG 1.105. Furthermore, continued surveillance testing will monitor relay performance such that degraded performance or reduced reliability of the LVR relays will be identified and addressed under the licensee's corrective action programs. The NRG staff determined the uncertainty factors used by the licensee in the LVR setpoint calculations are acceptable.

3.4.2.6 DVR Time Delay (With SIAS) Settings The licensee calculated TLU for the time delay setting of the DVRs. Statistical data based on surveillance test results indicated that actual instrument timing performance was within the calculated uncertainty values.

These time settings establish a margin of 1.5 seconds between the TSAV time and the established upper and lower ALs, which provides a 25 percent margin to the AL. These margins provide reasonable assurance the ALs will not be exceeded during plant operations.

The NRG staff finds this setting is acceptable because it provides adequate upper and lower margins with consideration of the established TLU instrument uncertainties. Therefore, the DVR relays have demonstrated performance of 95/95 reliability and confidence levels as specified in RG 1.105. The NRG staff finds this setting is acceptable because it provides an adequate margin between allowable values and the analytical limits established for this function.

3.4.2.7 DVR Time Delay (Without SIAS) Settings The licensee calculated TLU for the time delay setting of the DVRs. A limited set of statistical data based on surveillance test results obtained from another plant indicated that actual instrument timing performance was within the expected uncertainty values calculated by the licensee.

These time settings establish a margin of 3.6 seconds between the TSAV time and the established lower AL, which provides a 47.4 percent margin to the AL. The margin at the upper end is 4 seconds and provides a 44.4 percent margin to the upper AL. These margins provide reasonable assurance the AL will not be exceeded during plant operations. The NRG staff finds this setting is acceptable because it provides adequate upper and lower margins with consideration of the established TLU instrument uncertainties. Therefore, the DVR relays have demonstrated performance of 95/95 reliability and confidence levels as specified in RG 1.105.

The NRC staff finds this setting is acceptable because it provides an adequate margin between allowable values and the analytical limits established for this function.

3.4.2.8 L VR Time Delay Settings The licensee calculated TLU for the time delay setting of the LVRs. Statistical data based on surveillance test results indicated that actual instrument timing performance was well within the expected uncertainty values calculated.

The LVR time settings establish a margin of 0.2 seconds between the TSAV time and the established lower ALs, which provides a 25 percent margin to the AL. The margin at the upper end is 0.2 seconds and provides a 40 percent margin to the upper AL. These margins provide reasonable assurance the ALs will not be exceeded during plant operations. The NRC staff finds this setting is acceptable because it provides adequate upper and lower margins with consideration of the established TLU instrument uncertainties. Therefore, the LVR relays have demonstrated performance of 95/95 reliability and confidence levels as specified in RG 1.105.

The NRC staff finds this setting is acceptable because it provides an adequate margin between allowable values and the analytical limits established for this function.

3.4.3 Evaluation of TS Changes As discussed in this SE, the NRC staff reviewed the proposed new SR 3.3.7.4 and determined that the revised DVR and LVR relay settings are sufficient to ensure minimum required voltage levels on the 4.16 kV Class 1 E buses are maintained. The NRC staff determined that the allowable values were correctly stated in the revised SR. The channel calibration for the new relays will be performed at a frequency specified in the surveillance frequency control program, which is consistent with the channel calibration frequency of the existing relays, and is acceptable.

The Notes that modify SRs 3.3.7.3 and 3.3.7.4 clearly indicate the appropriate SR, dependent on whether the relay has been modified with a two stage time delay for the degraded voltage relays and a fixed time delay for the loss of voltage relays or not. The NRC staff determined that this is an appropriate clarifying note for the SRs.

In summary, the NRC staff determined that the revised SRs continue to specify the appropriate requirements to ensure facility operation will be within safety limits, and that the LCO will be met.

The NRC staff reviewed the proposed modification to LCO 3.8.1 Condition G. LCO 3.8.1, Condition G, applies when one or more required offsite circuits do not meet required capability.

The licensee stated that the new design will rely upon the actuation of the degraded voltage protection scheme on a deterministic basis, without crediting the preventive administrative controls implemented per LCO 3.8.1, Condition G, and that Condition G would no longer be applicable once the modification is complete. The staff reviewed the licensee's statement and the reason for Condition G stated in the Bases for LCO 3.8.1, Condition G, and concluded that LCO 3.8.1, Condition G would no longer be necessary once the modifications are completed.

Therefore, the Note stating that Condition G is not applicable for Class 1 E buses provided with a two stage delay for the degraded voltage relays and a fixed time delay for the loss of voltage relays is appropriate.

The NRC staff reviewed the proposed changes for consistency with conventional terminology and with the format and usage rule embodied in the TS. The staff finds that the proposed changes to the TS are consistent with applicable guidance.

Along with the proposed TS changes, the licensee also submitted TS Bases changes corresponding to the proposed TS changes. The regulation at 1 O CFR 50.36(a)(1) states, in part: "A summary statement of the bases or reasons for such specifications... shall also be included in the application, but shall not become part of the technical specifications."

3.4.4 Human Performance Aspects In accordance with the generic risk categories described in NUREG-1764, revising TS requirements as a result of the modification to the degraded and loss of voltage relays is considered not "risk-important" due to the fact that there are no changes to operator actions or changes to the control room design. Because of its low risk importance, the NRC staff performed a "Level Three" review (i.e., the least stringent of the graded reviews possible under the guidance of NUREG-1764). The results of the NRC staff's review are described below.

3.4.4.1 Description of Operator Action(s) Added/Changed/Deleted The licensee stated in its response to RAl-1 by letter dated July 21, 2016, that no operator manual actions will be added, deleted, or changed to support the proposed license amendment.

The change to the degraded voltage scheme adds a short stage timer (less than 10 seconds) to respond to a degraded voltage condition concurrent with a SIAS. The existing DVR time delay (approximately 35 seconds) remains essentially unchanged for degraded voltage conditions without a SIAS present. The L VR time delay design is changed from an inverse time delay relay to a fixed time delay. The time delays and relay actuations are automatic and do not require operator manual actions.

Operator actions to respond to the automatic actuations of the DVRs and LVRs, including actions to assure correct configuration for the plant status, are also unchanged with the proposed amendment.

The proposed modification will not add, delete or change operator manual actions; therefore the NRC staff finds this aspect of the proposed LAR is acceptable.

3.4.4.2 Human-System Interface Design The licensee stated in its response to RAl-3 by letter dated July 21, 2016, that no changes to controls or displays will be required to support the proposed license amendment. The DVR and LVR automatic actuations are annunciated in the control room but the time delays are not displayed or controlled in the control room.

Furthermore, as stated in Section 3.1, "Degraded Voltage Relay," of the LAR dated April 1, 2016, neither the alarm function in the control room nor the coincidence logic for the actuation of the DVRs and LVRs are affected by the proposed modification. The setpoints for the alarm function (voltage and time delay) are not proposed to be altered.

The proposed amendment will not have an effect on the control room displays, which is appropriate; therefore the NRC staff finds this aspect of the proposed LAR is acceptable.

3.4.4.3 Procedure Design The licensee stated in its response to RAl-2 by letter dated July 21, 2016, that the proposed license amendment changes the PVNGS design and licensing basis such that the design will rely upon the automatic actuation of the degraded voltage protection scheme (DVRs and LVRs) without crediting the current administrative controls (implementing TS 3.8.1, Condition G), once the modifications are completed on each of the Class 1 E buses in each of the three PVNGS units.

Although the licensee stated that the current administrative controls will not be credited, as stated in Section 2.2, "Need for Proposed Changes," of the LAR, by letter dated April, 1, 2016, the administrative controls will remain as a defense-in-depth preventive strategy, as compared to being the licensed success path for degraded voltage protection. They are documented in the TS bases and support the operability of the preferred offsite sources.

The licensee listed the specific procedures that will be changed to implement the proposed modifications to the DVRs and L VRs:

40AL-9RK1A, Panel 801A Alarm Responses 40AL-9RK1 B, Panel 8018 Alarm Responses 40AL-9RK1 C, Panel 801C Alarm Responses 40ST-9ZZ37, Inoperable Power Sources Action Statement The licensee further stated that these procedures will contain descriptions of the setpoints and the time delays for the DVRs and L VRs used in the proposed degraded voltage protection scheme and will be tracked through completion as part of implementation of the approved license amendment. Additionally, the emergency operating procedures are not affected.

The NRC staff has reviewed the licensee's approach to revising affected procedures and finds the licensee's description of proposed changes to the procedures is acceptable.

3.4.4.4 Training Program and Simulator Design The licensee stated in its response to RAl-4 by letter dated July 21, 2016, that actions have been created to ensure updates to training materials and settings affected by the proposed modification and LAR, and are completed as part of implementation of the approved license amendment.

The licensee stated that the following lesson plans and simulator modeling will be updated to implement the proposed modifications to the DVRs and LVRs:

Lesson plan regarding the balance of plant engineering safety features actuation system Simulator lesson plan for loss of offsite power/loss of forced circulation Licensed operator initial training lesson plan Licensed operator continuing training lesson plan Simulator modeling for degraded voltage protection scheme (DVRs and LVRs)

The licensee further stated that the updates to the training materials and simulator design will address the changes to the SRs of TS 3.3.7, the type and design of relays installed for the Class 1 E buses, and transitioning to automatic actuation of the DVRs and LVRs for degraded voltage protection for SIAS and non-SIAS plant events.

Based on the above considerations, the NRC staff finds the licensee's approach for updating operator training and simulator design is acceptable.

3.5 Summary This LAR proposes to change the PVNGS design and licensing basis such that the design will rely upon the actuation of the degraded voltage protection scheme (DVRs and LVRs) on a deterministic basis, without crediting the preventive administrative controls implemented for TS 3.8.1, Condition G, once the modifications are completed. The current 1-hour required action completion time of LCO 3.8.1, Condition G, would no longer be applicable once the modification is complete on Class 1 E bus( es) for the PVNGS units, since the design will rely on the automatic actuation of the relays without crediting administrative controls. Following the completion of the modifications, an administrative LAR will be submitted to remove TS 3.8.1, Condition G, and the old relay information from SR 3.3.7.3. The administrative controls, as documented in the TS Bases, will remain as a defense-in-depth preventive strategy, as compared to being the licensed success path for degraded voltage protection.

The existing and proposed design of DVRs and LVRs at PVNGS incorporates four protective channels in a two-out-of-four trip logic for each division of the 4.16 kV power supply. The licensee has stated that no single sensor failure will cause or prevent protective system actuation. The NRC staff concludes that each channel is independent, starting from voltage sensors to actuating devices and as such, any single failure in one channel will not result in separation of the related safety bus from the selected power source until a two-out-of-four trip logic is satisfied. This is in accordance with channel separation requirements of IEEE 279-1971, will preclude spurious simultaneous isolation of onsite and offsite power sources, and therefore is acceptable.

The NRC staff has reviewed the licensee's proposed TS changes and supporting documentation. The NRC staff has determined that the proposed modifications to the PVNGS, Units 1, 2, and 3, TS regarding the DVRs and the LVRs, and the addition of a short stage DVR will provide reasonable assurance that automatic actuation of the degraded and/or loss of voltage relays will ensure proper equipment performance during postulated events. The staff has also concluded that the proposed changes are consistent with the requirements in 10 CFR Part 50, Appendix A, GDC 17; 10 CFR 50.36; and the guidance in BTP 8-6, IEEE Standard 279-1971 and IN 95-05. Therefore, the staff finds the proposed changes acceptable.

Based on its review of the licensee's application, the NRC staff concludes the systems will continue to meet the requirements of PVNGS UFSAR Criterion 13 and 20. The NRC staff determined the revised DVR and LVR relay settings to be sufficient to ensure minimum required voltage levels on the 4.16 KV Class 1 E buses are maintained. The N RC staff finds the licensee has performed the necessary setpoint calculations in conformance with RG 1.105, and RIS 2006-17. The NRC staff further concludes the proposed TS changes meet the requirements of 1 O CFR 50.36(c) and are, therefore, acceptable.

The addition of surveillance notes to applicable functions ensures instrument function operability will be controlled in the TS and additional uncertainties have been included in the as-found tolerances calculation in a manner acceptable to the NRC staff. The NRC staff finds there is reasonable assurance of adequate protection capabilities for the DVR and LVR instrumentation.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Arizona State official was notified of the proposed issuance of the amendments on March 27, 2017. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 1 O CFR Part 20 and change SRs.

The NRC staff has determined that the amendments involve 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 amendments involve no significant hazards consideration published in the Federal Register on May 24, 2016 (81 FR 32803), and there has been no public comment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant to 1 O CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.

6.0 CONCLUSION

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

Principal Contributors: Richard Stattel, NRR Tania Martinez-Navedo, NRR Margaret Chernoff, NRR DaBin Ki, NRR Date: April 27, 201 7

R.Beme~

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3-ISSUANCE OF AMENDMENTS TO REVISE TECHNICAL SPECIFICATIONS RELATED TO DEGRADED AND LOSS OF VOLTAGE RELAY MODIFICATIONS (CAC NOS. MF7569, MF7570, AND MF7571) DATED APRIL 27, 2017 DISTRIBUTION:

PUBLIC LPL4 r/f RidsACRS_MailCTR Resource RidsNrrDorllpl4 Resource RidsNrrDssStsb Resource RidsNrrLAPBlechman Resource RidsNrrPMPaloVerde Resource RidsRgn4MailCenter Resource RidsNrrDeEeeb Resource RidsNrrDeEicb Resource AD AMSA ccession N o.: ML1709 OFFICE NRR/DORL/LPL4/PM NAME Sling am DATE 4/12/17 OFFICE NRR/DE/EEEB/BC*

NAME JZimmerman DATE 3/24/17 OFFICE NRR/DORL/LPL4/BC NAME RPascarelli DATE 04/27/2017 RidsNrrDraAphb Resource RidsNrrDssSrxb Resource RStattel, NRR BGreen, NRR MChernoff, NRR SPeng, NRR TMartinez-Navedo, NRR GMatharu, NRR VHuckabay, NRR OA1 64

SE d

d t d **b

1 memoran um ae 1y e-ma1 NRR/DORL/LPL4/LA NRR/DE/EICB/BC*

NRR/DRNAPHB/BC (A)*

PBlechman MWaters GCasto 4/12/2017 12/15/16 3/29/17 NRR/DSS/STSB/BC* NRR/DSS/SRXB/BC**

OGC-NLO AKlein EOesterle STurk 3/28/17 4/17/2017 04/26/2017 NRR/DORL/LPL4/PM Slingam 04/27/2017 OFFICIAL AGENCY RECORD

v t e Letter Sequence Approval
CAC:MF7569, (Approved, Closed) CAC:MF7570, (Approved, Closed) CAC:MF7571, (Approved, Closed)
Initiation Request Acceptance Administration Questions 29 June 2016 17 August 2016 13 September 2016 Answers Results Approval Other: ML16230A604, ML16251A245
MONTHYEAR2016-08-18 [Table View]

ML17090A164

Text

SUBJECT:

Dear Mr. Bement:

Enclosures:

Attachment:

Attachment:

Attachment:

1.0 INTRODUCTION

1.1 Background

2.0 REGULATORY EVALUATION

3.0 TECHNICAL EVALUATION

3.1 Proposed TS Changes

4.0 STATE CONSULTATION

5.0 ENVIRONMENTAL CONSIDERATION

6.0 CONCLUSION

SUBJECT:

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