ML13212A201

Issuance of Amendment No. 258 Change to Licensing Basis Regarding Station Blackout

ML13212A201
Person / Time
Site:	Vermont Yankee
Issue date:	08/15/2013
From:	Richard Guzman Plant Licensing Branch 1
To:	Entergy Nuclear Vermont Yankee
Guzman R
References
TAC MF0422
Download: ML13212A201 (18)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 15, 2013 Site Vice President Entergy Nuclear Operations, Inc.

Vermont Yankee Nuclear Power Station P.O. Box 250 Governor Hunt Road Vernon, VT 05354

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION -ISSUANCE OF AMENDMENT TO RENEWED FACILITY OPERATING LICENSE RE: CHANGE TO LICENSING BASIS REGARDING STATION BLACKOUT (TAC NO. MF0422)

Dear Sir or Madam:

The Nuclear Regulatory Commission has issued the enclosed Amendment No. 258 to Renewed Facility Operating License No. DPR-28 for the Vermont Yankee Nuclear Power Station (VYNPS), in response to your application dated December 21,2012, as supplemented on March 19, April 29, May 7, May 14, and June 26,2013.

The licensee's application for the proposed amendment revised the VYNPS licensing basis relative to how the station satisfies the reqUirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.63, "Loss of all alternating current power," by replacing the Vernon Hydroelectric Station with an onsite diesel generator as the alternate alternating current power source that would provide acceptable capability to withstand a station blackout under 10 CFR 50.63(c)(2). The change involves revisions to the VYNPS facility and procedures described in the Updated Final Safety Analysis Report.

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

Sincerely, Richard V. Guzman, Senior Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor licensing Office of Nuclear Reactor Regulation Docket No. 50-271

Enclosures:

1. Amendment No. 258 to License No. DPR-28

2. Safety Evaluation cc w/encls: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ENTERGY NUCLEAR VERMONT YANKEE, LLC AND ENTERGY NUCLEAR OPERATIONS, INC.

DOCKET NO. 50-271 VERMONT YANKEE NUCLEAR POWER STATION AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 258 Renewed License No. DPR-28

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

A. The application for amendment filed by Entergy Nuclear Vermont Yankee, LLC and Entergy Nuclear Operations, Inc. (the licensee) dated December 21,2012, as supplemented on March 19, April 29, May 7, May 14, and June 26,2013, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance: (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

Enclosure 1

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2. Accordingly, the license is amended as indicated in the attachment to this license amendment, and paragraph 3.B of the Renewed Facility Operating License No. DPR-28 is hereby amended to read as follows:

(B) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 258, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

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

FOR THE NUCLEAR REGULATORY COMMISSION Robert H. Beall, Acting Chief Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the License Date of Issuance: . August 15, 2013

ATTACHMENT TO LICENSE AMENDMENT NO. 258 RENEWED FACILITY OPERATING LICENSE NO. DPR-28 DOCKET NO. 50-271 Replace the following page of the Renewed Facility Operating License with the attached revised page. The revised page is identified by amendment number and contains marginal lines indicating the areas of change.

Remove Page Insert Page 3 3

- 3 D. Entergy Nuclear Operations, Inc., pursuant to the Act and 10 CFR Parts 30, 40 and 70, to receive, possess, and use in amounts as required any Byproduct, source, or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components.

E. Entergy Nuclear Operations, Inc., pursuant to the Act and 10 CFR Parts 30 and 70, to possess, but not to separate, such byproduct and special nuclear material as may be produced by operation of the facility.

3. This renewed license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations: 10 CFR Part 20, Section 30.34 of 10 CFR Part 30, Section 40.41 of 10 CFR Part 40, Section 50.54 and 50.59 of 10 CFR Part 50, and Section 70.32 of 10 CFR Part 70; 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 below:

A. Maximum Power Level Entergy Nuclear Operations, Inc. is authorized to operate the facility at reactor core power levels not to exceed 1912 megawatts thermal in accordance with the Technical Specifications (Appendix A) appended hereto.

B. Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 258 are hereby incorporated in the license. Entergy Nuclear Operations, Inc. shall operate the facility in accordance with the Technical Specifications.

C. Reports Entergy Nuclear Operations, Inc. shall make reports in accordance with the requirements of the Technical Specifications.

D. This paragraph deleted by Amendment No. 226.

E. Environmental Conditions Pursuant to the Initial Decision of the presiding Atomic Safety and Licensing Board issued February 27, 1973, the following conditions for the protection of the environment are incorporated herein:

1. This paragraph deleted by Amendment No. 206, October 22,2001.

2. This paragraph deleted by Amendment 131, 10107/91.

Renewed Facility Operating License No. DPR-28 Amendment No. ~, 258

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 258 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-28 ENTERGY NUCLEAR VERMONT YANKEE, LLC AND ENTERGY NUCLEAR OPERATIONS, INC.

VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271

1.0 INTRODUCTION

By letter dated December 21,2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12362A041), as supplemented by letters dated March 19 (ML13085A079), April 29 (ML13123A059), May 7 (ML13133A037), May 14 (ML13137A155), and June 26, 2013 (ML13183A064), Entergy Nuclear Operations, Inc. (Entergy or the licensee) submitted a license amendment request (LAR) to revise the licensing basis relative to how Vermont Yankee Nuclear Power Station (VYNPS) satisfies the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.63, "Loss of all alternating current power."

The licensee proposed the replacement of the Vernon Hydroelectric Station (VHS) with an onsite diesel generator as the alternate alternating current (ac) power source that would provide acceptable capability to withstand a station blackout under 10 CFR 50.63(c)(2). The proposed change involves revisions to the VYNPS facility and procedures described in the Updated Final Safety Analysis Report (UFSAR).

The supplemental letters dated March 19, April 29, May 7, May 14, and June 26,2013, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the Nuclear Regulatory Commission (NRC) staffs original proposed no significant hazards consideration determination as published in the Federal Register on March 19,2013 (78 FR 16881).

2.0 REGULATORY EVALUATION

The licensee is proposing to change its approach for satisfying the Station Blackout (SBO) rule codified in 10 CFR 50.63, "Loss of all alternating current power." The objective of the rule is to reduce the risk of severe accidents resulting from station blackout by maintaining highly reliable ac electric power systems and, as additional defense-in-depth, assuring that plants can cope with a station blackout for some period oftime. Specifically, in Final Rule, Station Blackout,1 the rule requires all light-water-cooled nuclear power plants to be able to cope with a station 1 53 Federal Register 23,203, June 21,1988.

Enclosure 2

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blackout for a specified duration and to have procedures and training for such an event.

Regulatory Guide (RG) 1.155 "Station Blackout," issued along with the rule, provides an acceptable method to determine the station blackout duration for each plant. 3 The duration is to be determined for each plant based on a comparison of the individual plant design with factors that have been identified as the main contributors to risk of core melt resulting from station blackout. 4 These factors are (1) the redundancy of onsite emergency ac power sources, (2) the reliability of onsite emergency ac power sources, (3) the frequency of loss of offsite power, and (4) the probable time needed to restore offsite power.5 As described in Section 3.3.5 of RG 1.155, the Station Blackout rule allows taking credit for alternate ac power sources provided that certain criteria are met (e.g., independence, redundancy, high reliability, maintenance, and testing). The alternate ac source is addressed in the Station Blackout rule at 10 C.F.R. 50.63(c)(2) thusly:

Alternate ac source: The alternate ac power source(s), as defined in Section 50.2, will constitute acceptable capability to withstand station blackout provided an analysis is performed which demonstrates that the plant has this capability from onset of the station blackout until the alternate ac source(s} and required shutdown equipment are started and lined up to operate. The time required for startup and alignment of the alternate ac power source(s) and this equipment shall be demonstrated by test.

The alternate ac source is defined in Section 50.2 as follows:

Alternate ac source means an alternating current (ac) power source that is available to and located at or nearby a nuclear power plant and meets the following requirements:

(1) Is connectable to but not normally connected to the offsite or onsite emergency ac power systems; (2) Has minimum potential for common mode failure with offsite power or the onsite emergency ac power sources; (3) Is available in a timely manner after the onset of station blackout; and (4) Has sufficient capacity and reliability for operation of all systems required for coping with station blackout and for the time required to bring and maintain the plant in safe shutdown (non-deSign basis accident).

RG 1.155 notes that the information submitted to comply with Section 50.63 is required to be incorporated the final safety analYSis report (FSAR). With respect to Vermont Yankee, the site specific information on how Vermont Yankee meets the requirements of the Station Blackout rule is in Section 8.5.5.1 of the UFSAR. As described therein, Vermont Yankee is categorized as an eight-hour coping duration plant and uses an alternate ac source from the VHS to meet 10 CFR 50.63. Additionally other portions of the UFSAR elaborate on the alternate ac source. For example, UFSAR Section 8.3 further describes how the VHS and the associated power lines and transformers can be used to supply the 4160 V emergency buses. UFSAR Section 8.3 also 2 Id. at 23,217.

3 Id.

4 Id.

5 Id.

-3 describes the testing of the lines. Additional information regarding how the alternate ac supplies the 4160 V switchgear is presented in UFSAR Section 8.4.5.1.

In place of the VHS, the licensee now desires to rely upon a newly installed "Station Blackout Diesel Generator" (SBO DG) rated for continuous duty of 3,000 kW. Otherwise, its station blackout analysis and procedures are unchanged. Accordingly, the LAR included marked-up UFSAR pages showing how the SBO DG would be used as the alternate ac source.

3.0 TECHNICAL EVALUATION

3.1 Background Station blackout (SBO) refers to a complete loss of AC electric power to the essential and nonessential switchgear buses in a nuclear power plant. SBO involves a loss of offsite power concurrent with a turbine trip and unavailability of the onsite emergency AC power sources.

At VYNPS, two diesel generator sets are capable of being connected to the station switchgear to provide emergency power, as required. Upon loss of normal ac power, each of these diesel generator sets starts automatically and becomes available to assume the necessary electrical load of the station's engineered safeguards systems within the time required by the accident analysis. If one of the two diesel generators is not available, then the Vernon Hydroelectric Station line can be made available by a manual transfer to the associated engineered safeguard switchgear.

At VYNPS, a 13.2 kilo-Volt (kV) underground power line runs from the adjacent Vernon Hydroelectric Station to a 13.2-4.16 kV transformer near the cooling towers. From there, a 4160 Volt (V) underground power line connects to the station switchgear. This line which can be connected to either of the 4160 V emergency buses through manually operated circuit breakers, is designated as VYNPS's station blackout alternate ac power source for compliance with the SBO rule. This power source has the capacity to support the engineered safeguard load of the bus to which it is connected. To satisfy the SBO rule, the time required for startup and alignment of the alternate ac power source is currently demonstrated by test every third refueling outage.

A load capacity test of the alternate ac power source is also conducted.

The VHS is designated as a black-start facility under arrangements with Independent System Operator-New England (ISO-NE), the regional grid operator, which requires that the VHS be capable of being black-started within 90 minutes after the operator of the facility is notified.

The VYNPS is categorized as an 8-hour SBO coping duration plant. The VHS is currently credited as the alternate ac power source available at the VYNPS station safety buses within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of losing all offsite and onsite emergency ac power. The original VYNPS coping analysis demonstrated that VYNPS can withstand an SBO event during the initial2-hour interval. 6 As a result of a forthcoming change to the ISO-NE system restoration strategy, the contract between ISO-NE and the owner-operator of the VHS for black-start of the VHS will expire on 6 The NRC staff previously reviewed the licensee's current SBO coping analysis during the extended power uprate license amendment review (as documented in ADAMS Accession No. ML060050028). The proposed amendment does not require any changes to the existing coping analysis since the proposed onsite SBO DG will be available within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> following an SBO and thus, the existing coping analysis bounds the interval from onset of an SBO until the alternate ac power source is started and aligned. The licensee is not proposing any changes to the method of operation of systems or to the operating parameters used in the coping analysis.

-4 September 1, 2013, and will not be renewed. Additionally, the owner-operator of the VHS has declined to enter into a contractual agreement with the licensee to supply black-start power to allow VYNPS to meet the requirements of 10 CFR 50.63. Therefore, the VHS will not be able to be credited as an alternate ac power source as of September 1, 2013.

3.2 Licensee's Proposed Changes The VYNPS licensing basis with respect to the VHS function and its compliance with 10 CFR 50.63 is described in the VYNPS UFSAR, Section 8 and in the TS Bases. Specifically, the licensee's proposed changes consist of revisions to UFSAR Sections 8.1.1, 8.3.3, 8.3.4, 8.4.5.1, 8.5.5, 8.5.5.1 and TS Bases Section 3.1 O.A to reflect that the onsite SBO DG replaces the VHS as the source of alternate ac power credited for compliance with 10 CFR 50.63.

The renewed facility operating license and the Technical Specifications are not affected by the licensee's proposed licensing basis change. The VHS tie line is also credited for compliance with 10 CFR 50, Appendix R and for allowable Technical Specification configurations in TS 3.7.B.1.b. These specific functions are not affected by the licensee's proposed licensing basis change.

The licensee provided markups of the proposed changes to the UFSAR and TS Bases for the NRC staffs information in its December 21, 2012, LAR (ADAMS Accession No. ML12362A041).

In the LAR, the licensee stated that although the VHS will no longer be credited as the alternate ac power source at VYNPS, the VHS 13.2 kV tie line will remain normally energized from the Vernon 69 kV/13.2 kV switch yard and will be available to provide power to VYNPS whenever it is energized. The VHS tie line will normally be aligned to provide power through the existing 13.2 kV-4160 V transformer to a new 4,160 V ac bus being installed along with the new diesel generator. The new 4,160 V ac bus will also provide power to the new diesel generator system auxiliaries (such as battery chargers and heaters) that maintain the readiness of the diesel generator, but this ac power is not required to start the new diesel generator in the event of an SBO. The licensee stated that the new alternate ac power source will be available within 1-hour following an SBO.

As stated in the LAR, the new diesel generator and its auxiliary equipment will be located within enclosures that conform to the International Building Code, which superseded the Uniform Building Code. The electrical cables that connect the new diesel generator to the shutdown buses will be located within buried conduit or duct banks to provide protection against events that may initiate the loss of an off-site power event. The licensee noted that these cables will be included in its License Renewal Non-EO (environmental qualification) Inaccessible Medium Voltage Cable Program and subject to periodic inspection and testing in accordance with that program. Additionally, the manholes through which these cables are routed will be subject to periodic inspection in accordance with the licensee's Non-EO Inaccessible Medium Voltage Cable Program.

3.3 NRC Staff Evaluation The NRC staff evaluated the licensee's comparison of their proposed design to the applicable ac power source design criteria in RG 1.155 and Appendix B of NUMARC 87-00, Revision 1 to determine the adequacy of the proposed onsite diesel generator as the new alternate ac power source.

-5 The NRC staff requested the licensee to provide a summary of the licensee's detailed RG 1.155 analysis that considers the most up-to-date data (e.g., current grid reliability, loss of offsite power events, emergency diesel generator reliability, etc.) to show the minimum specified duration that VYNPS should be required to mitigate the consequences of an SBO event. The licensee responded to the NRC staffs request in its letter dated May 14, 2013. In its response, the licensee provided a summary of its revised SBO coping analysis. The licensee stated that according to their latest analysis, the VYNPS is categorized as Extreme Severe Weather Group 3, Severe Weather Group 2, and Offsite Power Group 13. Based on this information, the VYNPS is classified as being in offsite power design characteristic group P2. The VYNPS is in Emergency ac Group C and the emergency diesel generator target reliability is 0.95. Therefore, the duration for withstanding an SBO event for VYNPS remains at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

The NRC staff performed the following evaluations to determine the acceptability of new diesel generator as the new alternate ac power source. For the following evaluations, the staff utilized the guidance in RG 1.155 and Appendix B of NUMARC 87-00, Revision 1 to determine the adequacy of the proposed alternate ac power source design.

Rating of the new SBO diesel generator In its letter dated May 7,2013, the licensee stated that the existing Vernon Tie is supplied by a 3750 kilo-Volt-Ampere (kVA) transformer which, assuming a load power factor of 0.8, can supply a continuous 3000 kilo-Watt (kW) load. The Vernon Tie rating is slightly greater than the rating of each of the existing VYNPS Emergency Diesel Generators (EDGs) that function as the emergency ac power sources. The generator for the EDG is rated 3750 kVA at 0.8 power factor.

The new diesel generator's rating has a 3000 kW continuous rating and its generator is rated 3750 kVA at 0.8 pf.

Since the rating of the proposed diesel generator (3000 kW) is greater than each of the existing EDGs (2750 kW each), the NRC staff finds the rating of new diesel generator acceptable to supply the safe shutdown loads during an SBO event. This satisfies requirement 4 of the 10 CFR 50.2 definition for an alternate ac source since the licensee has demonstrated that the proposed ac power source has sufficient capacity for operation of all systems required for coping with station blackout and for the time required to bring and maintain the plant in safe shutdown (non-design basis accident).

Independence from the existing onsite emergency ac power system The new diesel generator system will be physically separated from Class 1E ac power systems by a considerable distance, so mechanical failure of the new diesel generator system will not impact the Class 1E ac power systems. The new diesel generator system will not normally be connected to the Class 1E ac power system except during an actual SBO or for periodic testing to demonstrate the ability to supply power to a single emergency bus (once per cycle).

Additionally, protective relaying will be provided to automatically isolate the new diesel generator electrical system upon failure of the new diesel generator such that an electrical fault will not propagate to the Class 1E ac power systems.

Based on this information, the NRC staff finds that a failure of the new diesel generator or its auxiliary equipment will not adversely affect Class 1E ac power systems. This satisfies requirements 1 and 2 of the 10 CFR 50.2 definition for an alternate ac source since the proposed ac power source is connectable to but not normally connected to the offsite or onsite

-6 emergency ac power systems and minimizes the potential for common mode failure with offsite power or the onsite emergency ac power sources.

Batteries (Starting Sources)

The NRC staff requested the licensee to provide a detailed discussion on the batteries used for the new diesel generator.

In its May 7,2013, response, the licensee noted that the batteries were selected by the diesel generator manufacturer (Caterpillar) to ensure sufficient capacity to start and operate the diesel generator. According to the licensee, only one 24 V dc starting battery is required to start and operate the diesel generator. However, two 24 V dc starting batteries are provided by the diesel generator manufacturer to allow for periodic maintenance and added conservatism. The licensee indicated that the capability of the batteries to start and operate the new diesel generator will be verified by factory and site acceptance testing. In addition, the batteries will be functionally tested at least every three months when the new diesel generator is started for surveillance testing. The licensee further indicated that these batteries will be included in the site preventative maintenance program, with maintenance performed per vendor recommendations or standard industry practice for this type of battery.

Based on the above, the NRC staff has determined there is reasonable assurance that the new diesel generator batteries will have the necessary capacity and capability to perform their intended function. This satisfies requirement 4 of the 10 CFR 50.2 definition for an alternate ac source since the licensee has demonstrated that the proposed ac power source has sufficient reliability for operation of all systems required for coping with station blackout and for the time required to bring and maintain the plant in safe shutdown (non-design basis accident).

Reliability In the LAR, the licensee stated that the target reliability for the new diesel generator system will be 0.95 in accordance with the Entergy Emergency Diesel Generator Program, which includes the guidance provided in NUMARC 87-00, Appendix D. The new diesel generator system will be included in the scope of the VYNPS Maintenance Rule Program.

Based on the above, the NRC staff has determined there is reasonable assurance that the new diesel generator system will maintain a target reliability of 0.95.

Ventilation The NRC staff requested the licensee to provide a discussion of the new diesel generator building's ventilation system.

The licensee provided details of the ventilation system in letters dated May 7 and June 26, 2013.

The licensee stated that the new diesel generator enclosure contains two cooling air inlet louvers that automatically open when the diesel generator is started. Hoods are located over each of the inlet louvers to provide protection against environmental hazards, with the air inlet on the bottom of each hood. The bottom of each hood will be located approximately 5 feet above grade, providing assurance that the air inlet will not become blocked due to snow accumUlation.

The new diesel generator enclosure also contains one cooling air exhaust louver that automatically opens when the diesel generator is started. The exhaust louver leads into a large

-7 plenum which directs the cooling air vertically out of the enclosure. The plenum is provided with drain holes to prevent accumulation of water.

Based on its review of the licensee's responses, the NRC staff finds that the new diesel generator building will provide reasonable protection against the effects of likely weather-related events that may initiate the loss of an off-site power event to VYNS.

Temperature Effects The NRC staff requested the licensee to provide a discussion of the minimum and maximum temperature requirements for the new diesel generator and its support systems.

In its May 7, 2013, response, the licensee stated that the new diesel generator system is required to be capable of operating at an ambient outdoor temperature range of -33 degrees Fahrenheit to 104 degrees Fahrenheit. These temperatures meet or exceed the extreme minimum and maximum data recorded for the Vernon, Vermont area as listed in Table 2.3.2 of the VYNPS UFSAR. The diesel generator enclosure is insulated and also heated with two (2) permanently installed 5 kilowatt electric heaters powered from the internal 480 V ac distribution panel. The diesel generator enclosure also includes a small thermostatically controlled exhaust fan to limit heat rise within the enclosure during standby operation. When the new diesel generator is operating, large louvers automatically open to provide air cooling. The switchgear enclosure also contains a wall-mounted heating ventilation and air conditioning unit that is designed to maintain enclosure temperature within the limits of the installed equipment.

Based on these features, the NRC staff has determined there is reasonable assurance that the new SBO diesel generator performance will not be impacted as a result of minimum and maximum ambient outdoor temperatures.

Indication, Controls, and Alarms In the LAR, the licensee indicated that the new diesel generator system can be controlled and operated from a remote operator interface panel (OIP) that will be installed in the VYNPS Control Room on the Control Room Panel 9-8 or manually controlled and operated from within the new diesel generator's switchgear enclosure.

The NRC staff requested the licensee to provide additional details on the OIP. In its May 7, 2013, response, the licensee stated that the OIP located on Control Panel 9-8 will be functionally identical to the OIP local to the new diesel generator switchgear, with the same capabilities to operate and monitor all aspects of the new diesel generator system.

During normal operation. a direct operator action at the switchgear or generator enclosures will not be required. The licensee also stated that the new OIP will increase load on the 120 V ac vital ac panel VAC-A by approximately 1.7 amps. The consequential net increase in vital motor generator set dc drive motor and station battery load will be approximately 1.7 amps.

Based on the above, the NRC staff finds that the licensee has adequately addressed the impact of the additional loading of the OIP on the vital ac and dc systems and that the existing vital ac and dc systems have adequate capability and capacity to support the additional small load.

- 8 The NRC staff requested the licensee to provide a discussion on control room alarms to indicate loss of power to the distribution panel or other relevant indications to ensure timely operator response to an SBa condition.

In its May 7,2013, response, the licensee noted that an annunciator window located on Control Room Panel 9-8 will provide alarm indication for a general trouble condition on the new diesel generator system. A complete loss of power to the 480 V ac distribution panel of the new diesel generator will cause multiple alarm conditions, such as loss of power alarms to battery chargers, that will be annunciated on Control Room Panel 98. A complete loss of power to the 4,160 V ac SBa diesel generator switchgear will be annunciated via another annunciator window located on Control Room Panel 9-8.

Based on this information, the NRC staff has determined there is reasonable assurance that the alarms and indications for the new diesel generator system will ensure timely operator response to an SBa condition.

Maintenance and Testing In the LAR, the licensee stated that the new diesel generator will be maintained in a "ready to operate" condition such that it can be started and connected to one of the safety buses (Bus 3 or Bus 4) in a timely manner. Following installation of the new alternate ac power source, the licensee will perform initial testing to demonstrate that power can be made available up to existing circuit breaker 3V4 within one hour of the onset of an SBa.

Based on the above, the NRC staff finds that the proposed testing for the new diesel generator will demonstrate that the diesel generator can be aligned to one of the safety buses within one hour; therefore, the existing two-hour coping analysis bounds the interval between onset of an SBa and the start and alignment of the new diesel generator.

As stated in the LAR, the licensee will perform initial testing by loading the new diesel generator to its rated output (3,000 kW) using a permanently installed resistive load bank. Testing to the rating output would demonstrate that the alternate ac power source can provide the power required to operate the required shutdown equipment at VYNPS. Acceptance testing of the new diesel generator will include starting of an unloaded 4 kV induction motor that provides a starting current equal to or higher than the largest motor on safety Bus 3 or safety Bus 4, which is the 1000 horsepower Residual Heat Removal (RHR) pump motor. The licensee will monitor the generator output voltage and frequency during the motor start to ensure that allowable limits are not exceeded.

The NRC staff finds that this one-time testing will demonstrate the ability of the new diesel generator to start the RHR pump while maintaining operating voltage and frequency within the limits established for safe shutdown components. This satisfies requirement 3 of the 10 CFR 50.2 definition for an alternate ac source since the licensee has demonstrated that the proposed ac power source will be available in a timely manner after the onset of station blackout.

The licensee will also periodically test the alternate ac power source in accordance with procedures developed from the licensee's quality assurance program. Post-maintenance testing of the alternate ac power system will be performed and controlled in accordance with the licensee's procedures. This will ensure that portions of the alternate ac power system subject to maintenance activities are appropriately tested prior to returning the alternate ac power system to service.

-9 In its response dated June 26,2013, to an NRC staff request for additional information, the licensee provided results of the motor start testing performed before shipment of the new diesel generator to the VYNPS. The diesel generator voltage and frequency were monitored while starting a test motor which is 2S% larger than the existing RHR pump motor. The licensee used this voltage and frequency data to determine the transient response of the new diesel generator and to verify that voltage regulation and speed control would be acceptable for the in-plant configuration. The licensee compared the voltage drop to the voltage drop for the start of a single RHR pump motor from the VYNPS emergency diesel generator, as described in Section 8.S.3 of the VYNPS UFSAR.

The NRC staff reviewed the results of the above motor start test, and determined that the results demonstrate that the new diesel generator can start the largest RHR pump motor load during an SSO event. This satisfies requirement 4 of the 10 CFR SO.2 definition for an alternate ac source since the licensee has demonstrated that the proposed ac power source has sufficient capacity and reliability for operation of all systems required for coping with station blackout and for the time required to bring and maintain the plant in safe shutdown (non-design basis accident).

As discussed above, the NRC staff has determined that (1) the licensee's new diesel generator as the new alternate ac power source constitutes acceptable capability to withstand the station blackout; and (2) the licensee has provided an analysis that demonstrates that the plant will have the capability from onset of the SSO until the alternate ac source and required shutdown equipment are started and lined up to operate as demonstrated by an acceptable test; therefore, the NRC staff finds that the requirements of 10 CFR SO.63(c)(2) are satisfied.

Fuel Oil Supply In the LAR, the licensee indicated that the new SSO diesel generator will include a dedicated fuel oil storage tank with a capacity sufficient for operation of the diesel generator at 100% rated load for at least 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />, which provides significant margin over the existing design basis eight hour coping time.

The NRC staff requested the licensee to provide additional information on the fuel oil requirements for the new diesel generator. In its May 7,2013, response, the licensee referenced the diesel generator manufacturer's data sheet which identified a fuel consumption rate of 214.2 gallons/hour at 100% loading. Given that the fuel tank capacity is 9,604 gallons, with 8,074 gallons of useable fuel, operating the new diesel generator at 100% loading with a full fuel tank, the new diesel generator can run for more than 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> (more than the required 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> SSO coping duration). The licensee will administratively control the fuel oil level to ensure that sufficient fuel is available to support operating the new diesel generator at 100% loading for 8-hour SSO coping duration. In its April 29, 2013, response, the licensee stated that an ac powered fuel oil transfer pump will transfer fuel oil from the SSO diesel generator dedicated fuel oil storage tank to the day tank. The fuel oil transfer pump is energized during engine starting and continues to operate while the SSO diesel generator is operating. Fuel from the day tank is gravity fed to the SSO diesel generator skid through a duplex fuel filter located in the SSO diesel generator enclosure. The licensee also stated that one possible means to refill the SSO diesel generator fuel oil storage tank will be from the existing EDG fuel oil storage tank using a portable tank or a temporary connection between the two tanks. Pump power can be supplied from new Sus 13 via the load center located in the SSO diesel generator enclosure. Sus 13 is powered by the SSO diesel generator; therefore, any electric-driven pump need to transfer the fuel oil will remain powered during an SSO event. The licensee stated that other possible ways of

- 10 transferring the fuel oil include vendor-supplied deliveries, manual pumps, or other vehicle battery-powered pumps.

Based on this information, the NRC staff has determined there is reasonable assurance that sufficient fuel oil will be available to support operating the new diesel generator at 100% loading for the a-hour SBO coping duration. This satisfies requirement 4 of the 10 CFR 50.2 definition for an alternate ac source since the licensee has demonstrated that the proposed ac power source has sufficient fuel oil capacity for operation of all systems required for coping with station blackout and for the time required to bring and maintain the plant in safe shutdown (non-design basis accident).

3.4 Regulatory Commitments The licensee made the following regulatory commitments in its LAR, as supplemented, which have been or will be completed before or concurrently with the amendment implementation as noted in parentheses:

1. (Entergy letter dated December 21,2012). Acceptance testing of the SBO DG unit will include starting of an unloaded 4 kV induction motor that provides a starting current equal to or higher than the largest motor on safety Bus 3 or safety Bus 4, which is the 1000HP Residual Heat Removal (RHR) pump motor. The generator output voltage and frequency will be monitored during the motor start to ensure that allowable limits are not exceeded. This one-time testing will demonstrate the ability of the new generator to start the RHR pump while maintaining operating voltage and frequency within the limits established for safe shutdown components. (One-time action to be completed by September 1,2013).

2. (Entergy letter dated December 21,2012). Following installation of the new AAC power source, initial testing will be performed to demonstrate that power can be made available up to existing circuit breaker 3V4 within one hour of the onset of station blackout. (One time action to be completed by September 1, 2013).

3. (Entergy letter dated December 21, 2012). The SBO DG equipment will be started and brought to approximately rated load capacity (3,OOOkW) at quarterly intervals in accordance with plant-developed procedures and preventive maintenance work order tasks established in accordance with manufacturer recommendations and industry guidance. The electrical load for the SBO DG for this test will be provided by a permanently installed 3,OOOkW resistive load bank located adjacent to the SBO DG enclosure. (Periodically/continually performed to maintain compliance with SBO rule).

4. (Entergy letter dated December 21, 2012). Once every refueling outage, a timed start will be performed to demonstrate that the AAC power source can be started and aligned to either safety Bus 3 or safety Bus 4 within one (1) hour. (Periodically/continually performed to maintain compliance with SBO rule - first test will be performed during VYNPS refueling outage 31).

5. (Entergy letter dated December 21, 2012). Once every third refueling outage, the SBO DG will be demonstrated by test to be capable of starting the largest available motor on safety Bus 3 or safety Bus 4. (Periodically/continually performed to maintain compliance with SBO rule - first test will be performed during VYNPS refueling outage 31).

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6. (Entergy letter dated March 19, 2013). Provide a summary of the detailed Regulatory Guide (RG) 1.155, "Station Blackout," analysis, considering the most up-to-date data (e.g., current grid reliability, loss of offsite power events, EDG reliability, etc.), showing the minimum specified duration that Vermont Yankee should be required to mitigate the consequences of an SBO event by May 15, 2013. (Completed by letter dated May 14, 2013).

The NRC staff finds that reasonable controls for the implementation and for subsequent evaluation of proposed changes pertaining to the above regulatory commitments are best provided by the licensee's administrative processes, including its commitment management program. The above regulatory commitments do not warrant the creation of regulatory requirements (items requiring prior NRC approval of subsequent changes).

3.5 NRC Staff Conclusion

The NRC staff has evaluated the proposed change to revise the licensing basis relative to how VYNPS satisfies the requirements of 10 CFR 50.63. As part of its submittal, the licensee provided a comparison of the proposed design to the applicable alternate ac power source design criteria in RG 1.155 and Appendix B of NUMARC 87-00, Revision 1. The NRC staff reviewed this comparison and finds that the licensee has adequately addressed each parameter thereby demonstrating that the proposed design for the new diesel generator system meets the guidelines for an alternate ac power source. The licensee has demonstrated that the new SBO diesel generator system satisfies the requirements of 10 CFR 50.63(c)(2) as well as the requirements defined in 10 CFR 50.2 for an alternate ac source, to ensure that VYNPS can withstand and recover from an SBO for a specified duration of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Based on the above evaluation, the NRC staff has determined that the proposed design change conforms to the requirements of 10 CFR 50.63; and therefore, is acceptable.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Vermont State official was notified of the proposed issuance of the amendment. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in amounts, and no significant change in the types of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (78 FR 16881, March 19,2013). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

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6.0 CONCLUSION

The NRC staff 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 amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: M. McConnell, NRRIDE/EEEB Date: August 15, 2013

August 15, 2013 Site Vice President Entergy Nuclear Operations, Inc.

Vermont Yankee Nuclear Power Station P.O. Box 250 Governor Hunt Road Vernon, VT 05354

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION -ISSUANCE OF AMENDMENT TO RENEWED FACILITY OPERATING LICENSE RE: CHANGE TO LICENSING BASIS REGARDING STATION BLACKOUT (TAC NO. MF0422)

Dear Sir or Madam:

The Nuclear Regulatory Commission has issued the enclosed Amendment No. 258 to Renewed Facility Operating License No. DPR-28 for the Vermont Yankee Nuclear Power Station (VYNPS), in response to your application dated December 21,2012, as supplemented on March 19, April 29, May 7, May 14, and June 26.2013.

The licensee's application for the proposed amendment revised the VYNPS licensing basis relative to how the station satisfies the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.63, "Loss of all alternating current power," by replacing the Vernon Hydroelectric Station with an onsite diesel generator as the alternate alternating current power source that would provide acceptable capability to withstand a station blackout under 10 CFR 50.63(c)(2). The change involves revisions to the VYNPS facility and procedures described in the Updated Final Safety Analysis Report.

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

Sincerely, Ira!

Richard V. Guzman, Senior Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-271

Enclosures:

1. Amendment No. 258 to License No. DPR-28

2. Safety Evaluation cc w/encls: Distribution via Listserv DISTRIBUTION:

PUBLIC RidsRgn1MailCenter RidsNrrDorlLpl1-1 Resource RidsNrrLAKGoldstein RidsNrrOeEeeeb Resource RidsAcrsAcnw_MailCenter Resource M. McConnell. NRR RidsNrrDorlDpr Resource RidsNrrPMVermontYankeeResource R. Wolfgang. NRR RidsNrrDeEptb Resource

• Concurrence via email **SE Input via memo. No substantial changes made.

Accession No: ML13212A201 NRR-106 OFFICE LPL1-1/PM ILPL1-1/LA EPTB/BC* EEEB/BC{A)** OGC LPL1-1IBC{A)

NAME RGuzman KGoldstein Tsao for TLupold RMathew DRoth RBeali DATE 811/13 811/13 8/1/13 7/29/13 8/14/13 8115113 OFFICIAL RECORD COpy