Text

Amends 232,232 & 231 to Licenses DPR-38,DPR-47 & DPR-55, Respectively,Revising Current TSs Re Electrical Distribution Sys & Incorporate New Requirements for Sys Operation, Limiting Conditions for Operation & SR
	ML15261A464
Person / Time
Site:	Oconee
Issue date:	09/04/1998
From:	Berkow H; NRC (Affiliation Not Assigned)
To:	;
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ML15261A466	List: ML15261A464; ML15261A468;
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REQ UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 DUKE ENERGY CORPORATION DOCKET NO. 50-269 OCONEE NUCLEAR STATION, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 232 License No. DPR-38

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

A. The application for amendment to the Oconee Nuclear Station, Unit 1 (the facility)

Facility Operating License No. DPR-38 filed by the Duke Energy Corporation (the licensee) dated March 11, 1993, as supplemented August 26, October 26, November 29, and December 6, 1993, October 3, 1995, February 27, May 2, and September 3, 1997, and May 7, 1998, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as 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 set forth in 10 CFR Chapter I; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2. Accordingly, the license is hereby amended by page changes to the Technical Specifications as indicated in the attachment to this license amendment, and Paragraph 3.B of Facility Operating License No. DPR-38 is hereby amended to read as follows:

9809140152 980904 PDR ADOCK 05000269 PDR

-2 B. Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 232 , 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 coincident with implementation of the Improved Technical Specifications.

FOR THE NUCLEAR REGULATORY COMMISSION r rt N. Berk w, Direct r Project Directorate 11-2 Division of Reactor Projects - III Office of Nuclear Reactor Regulation

Attachment:

Technical Specification Changes Date of Issuance: September 4, 1998

REaj4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 DUKE ENERGY CORPORATION DOCKET NO. 50-270 OCONEE NUCLEAR STATION, UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 232 License No. DPR-47

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

A. The application for amendment to the Oconee Nuclear Station, Unit 2 (the facility)

Facility Operating License No. DPR-47 filed by the Duke Energy Corporation (the licensee) dated March 11, 1993, as supplemented August 26, October 26, November 29, and December 6, 1993, October 3, 1995, February 27, May 2, and September 3, 1997, and May 7, 1998, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as 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 set forth in 10 CFR Chapter 1; 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 hereby amended by page changes to the Technical Specifications as indicated in the attachment to this license amendment, and Paragraph 3.B of Facility Operating License No. DPR-47 is hereby amended to read as follows:

-2 B. Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 232 , 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 coincident with implementation of the Improved Technical Specifications.

FOR THE NUCLEAR REGULATORY COMMISSION erbert N. Berkow, irector Project Directorate 11-2 Division of Reactor Projects - 1/Il Office of Nuclear Reactor Regulation

Attachment:

Technical Specification Changes Date of Issuance: September 4, 1998

UNITED STATES NUCLEAR REGULATORY COMMISSION x WASHINGTON, D.C. 20555-0001 DUKE ENERGY CORPORATION DOCKET NO. 50-287 OCONEE NUCLEAR STATION, UNIT 3 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 231 License No. DPR-55

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

A. The application for amendment to the Oconee Nuclear Station, Unit 3 (the facility)

Facility Operating License No. DPR-55 filed by the Duke Energy Corporation (the licensee) dated March 11, 1993, as supplemented August 26, October 26, November 29, and December 6, 1993, October 3, 1995, February 27, May 2, and September 3, 1997, and May 7, 1998, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as 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 set forth in 10 CFR Chapter I; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2. Accordingly, the license is hereby amended by page changes to the Technical Specifications as indicated in the attachment to this license amendment, and Paragraph 3.B of Facility Operating License No. DPR-55 is hereby amended to read as follows:

-2 B. Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 231 , 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 coincident with implementation of the Improved Technical Specifications.

FOR THE NUCLEAR REGULATORY COMMISSION H rbert N. Berkow, irector Project Directorate 11-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation S

Attachment:

Technical Specification Changes Date of Issuance: September 4, 1998

ATTACHMENT TO LICENSE AMENDMENT NO. 232 FACILITY OPERATING LICENSE NO. DPR-38 DOCKET NO. 50-269 AND TO LICENSE AMENDMENT NO. 232 FACILITY OPERATING LICENSE NO. DPR-47 DOCKET NO. 50-270 AND TO LICENSE AMENDMENT NO. 231 FACILITY OPERATING LICENSE NO. DPR-55 DOCKET NO. 50-287 Replace the following pages of the Appendix "A" Technical Specifications with the enclosed pages. The revised pages are identified by Amendment number and contain vertical lines indicating the areas of change.

Remove Insert iv iv vi vi 3.7-1 through 3.7-16 3.7-1 through 3.7-32 B 3.7-1 through B 3.7-70 6.6-5 6.6-5

Section Page 3.10 GAS STORAGE TANK AND EXPLOSIVE GAS MIXTURE 3.10-1 3.11 (Not Used) 3.11-1 3.12 REACTOR BUILDING POLAR CRANE AND AUXILIARY HOIST 3.12-1 3.13 SECONDARY SYSTEM ACTIVITY 3.13-1 3.14 SNUBBERS 3.14-1 3.15 CONTROL ROOM PRESSURIZATION AND FILTERING SYSTEM 3.15-1 AND PENETRATION ROOM VENTILATION SYSTEMS 3.16 HYDROGEN PURGE SYSTEM 3.16-1 3.17 (NOT USED) 3.18 STANDBY SHUTDOWN FACILITY 3.18-1 4 SURVEILLANCE REQUIREMENTS 4.0-1 4.0 SURVEILLANCE STANDARDS 4.0-1 4.1 OPERATIONAL SAFETY REVIEW 4.1-1 4.2 STRUCTURAL INTEGRITY OF ASME CODE CLASS 1, 2 4.2-1 AND 3 COMPONENTS 4.3 TESTING FOLLOWING OPENING OF SYSTEM 4.3-1 4.4 REACTOR BUILDING 4.4-1 4.4.1 Containment Leakage Tests 4.4-1 4.4.2 Structural Integrity 4.4-14 4.4.3 Hydrogen Purge System 4.4-17 4.4.4 Reactor Building Purge System 4.4-20 4.5 EMERGENCY CORE COOLING SYSTEMS AND REACTOR 4.5-1 BUILDING COOLING SYSTEMS PERIODIC TESTING 4.5.1 Emergency Core Cooling Systems 4.5-1 4.5.2 Reactor Building Cooling Systems 4.5-4 4.5.3 Containment Heat Removal Capability 4.5-6 4.5.4 Penetration Room Ventilation System 4.5-7 4.5.5 Low Pressure Injection System Leakage 4.5-9 4.6 (NOT USED) 4.7 REACTOR CONTROL ROD SYSTEM TESTS 4.7-1 4.7.1 Control Rod Trip Insertion Time 4.7-1 4.7.2 Control Rod Program Verification 4.7-2 4.8 MAIN STEAM STOP VALVES 4.8-1 Oconee Units 1, 2, & 3 iv Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

LIST OF TABLES Table No. Page 2.3-1 Reactor Protective System Trip Setting Limits Units 1,2 and 3 2.3-5 3.5.1-1 Instruments Operating Conditions 3.5-4 3.5-1 (Not Used) 3.5-14 3.5.5-1 (Not Used) 3.5-39 3.5.5-2 (Not Used) 3.5-41 3.5.6-1 Accident Monitoring Instrumentation 3.5-45 3.7-1 (Not Used) 3.8-1 Minimum Qualifying Burnup Versus Initial Enrichment 3.8-6 for Unrestricted Storage in the Unit 1 and 2 Spent Fuel Pool 3.8-2 Minimum Qualifying Burnup Versus Initial Enrichment 3.8-7 for Filler Assemblies in the Unit 1 and 2 Spent Fuel Pool 3.8-3 Minimum Qualifying Burnup Versus Initial Enrichment 3.8-8 for Unrestricted Storage in the Unit 3 Spent Fuel Pool 3.8-4 Minimum Qualifying Burnup Versus Initial Enrichment 3.8-9 for Filler Assemblies in the Unit 3 Spent Fuel Pool 3.17-1 (Not Used) 3.18-1 SSF Minimum Instrumentation 3.18-6 4.1-1 Instrument Surveillance Requirements 4.1-3 4.1-2 Minimum Equipment Test Frequency 4.1-9 4.1-3 Minimum Sampling Frequency and Analysis Program 4.1-10 4.1-4 (Not Used) 4.1-16 4.4-1 (Not Used) 4.4-6 4.11-1 (Not Used) 4.11-3 4.11-2 (Not Used) 4.11-5 4.11-3 (Not Used) 4.11-8 4.17-1 Steam Generator Tube Inspection 4.17-6 4.20-1 SSF Instrumentation Surveillance Requirements 4.20-5 6.1-1 Minimum Operating Shift Requirements with Fuel in Three Reactor Vessels 6.1-6 Oconee Units 1, 2, & 3 vi Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

3.7.0 3.7 ELECTRICAL POWER SYSTEMS TS 3.7.0 Entry into operational conditions (e.g., HOT SHUTDOWN, COLD SHUTDOWN) specified in the Applicability shall not be made when the requirements of TS 3.7 are not met, unless the associated ACTIONS for the operational condition to be entered permit continued operation in the specified condition for an unlimited period of time.

This specification shall not prevent changes in the operational conditions specified in the Applicability which are required to comply with ACTIONS.

Other exceptions to this specification are stated in the individual specifications. These exceptions allow entry into operational conditions in the Applicability when the associated ACTIONS to be entered allow operation for only a limited period of time.

Oconee Units 1,2, & 3 3.7-1 Amendment 2 Unit I Amendment Z31._ Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 3.7 ELECTRICAL POWER SYSTEMS 3.7.1 AC Sources - Operating TS 3.7.1 The following AC electrical power sources shall be OPERABLE:

1.. One underground emergency piower path from one Keowee Hydro Unit through the S breakers,

2. One overhead emergency power path from a second Keowee Hydro Unit through the E breakers,

3. One underground emergency power path from a second Keowee Hydro Unit through the S breakers,

4. Two offsite sources on separate towers connected to the 230kV switchyard, and

5. One Lee gas turbine.

NOTES

1. The underground emergency power path specified in LCO 3.7.1.3 is not required to be OPERABLE when overhead electrical disconnects for the underground emergency power path specified in LCO 3.7.1.1 are open.

2. One Lee gas turbine is only required to be OPERABLE when:

a) underground emergency power path is inoperable> 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , b) overhead Keowee Hydro Unit is inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , c) Keowee Main Step-up transformer is inoperable 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , d) both emergency power paths are inoperable for planned reasons, e) both emergency power paths are inoperable > 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months for unplanned reasons, f) one or more required offsite sources are inoperable> I hour.

3. During periods of commercial power generation, the operability of the Keowee Hydro units shall be based on lake levels and the power level of the Keowee Hydro units. The Keowee Hydro operating restrictions for commercial power generation shall be contained in the ONS Selected Licensee Commitment manual.

APPLICABILITY: Above COLD SHUTDOWN Oconee Units 1,2, & 3 3.7-2 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or more required offsite A.1 Perform SR 3.7.1.4 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months if not sources and overhead emergency performed in previous power path inoperable due to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

inoperable startup transformer.

AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter.

AND A.2 Share another Unit's startup 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months transformer.

AND A.3 Designate shared startup 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months transformer to one Unit.

B. Shared startup transformer B.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months designated to one Unit.

AND OR B.2 Be in COLD SHUTDOWN 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months Required Actions and associated Completion Times not met for Condition A.

C. Overhead emergency power path C.1 Perform SR 3.7.1.4 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months if not inoperable due to reasons other performed in preceding than Condition A or B. 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Underground emergency power thereafter unless two path operable. standby buses are energized by an OPERABLE Lee gas turbine.

-(continued)

Oconee Units 1,2, &3 3.7-3 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. (continued) AND C.2 Enter applicable Conditions and 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Required Actions for overhead emergency power path inoperable for > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

NOTE Required Actions must be completed prior to entering applicable Conditions.

D. Underground emergency power D.1 Perform SR 3.7.1.5. 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months if not path inoperable. performed in preceding 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

AND AND Overhead emergency power path operable. Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter unless two standby buses are energized by an OPERABLE Lee gas turbine.

AND D.2 Energize a standby bus by an 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months OPERABLE Lee gas turbine. The 100kV transmission circuit shall be AND electrically separated from the system grid and all offsite loads. I hour from subsequent discovery of deenergized standby AND buses.

D.3 Restore underground emergency 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months power path to OPERABLE status.

(continued)

Oconee Units 1, 2, & 3 3.7-4 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME E. Required Action and associated E.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months for the first Completion Time for Required Oconee unit.

Action D.2 not met.

AND 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months for subsequent Oconee AND unit(s).

E.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months F. One inoperable E breaker and F. 1 Declare associated main feeder bus Immediately one inoperable S breaker on the inoperable.

same main feeder bus.

G. Both emergency power paths NOTE inoperable for planned reason TS 3.7.0 is not applicable when both other than Condition F. standby buses are energized by an OPERABLE Lee gas turbine.

G. 1 Energize two standby buses by an Prerequisite OPERABLE Lee gas turbine. The 100kV transmission circuit shall be AND electrically separated from the system grid and all offsite loads. I hour from subsequent discovery of deenergized standby AND buses.

G.2 Verify by administrative means the Prerequisite operability status of:

Two offsite sources (TS 3.7.1),

Distribution Systems (TS 3.7.2),

EPSL (TSs 3.7.3, 3.7.4, 3.7.6), DC Sources (TS 3.7.8), and Vital Inverters (TS 3.7.9).

(continued)

Oconee Units 1, 2, & 3 3.7-5 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME G. (continued) AND G.3 Restore inoperable components 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from discovery listed in G.2 to OPERABLE status. of inoperable component.

AND G.4 Restore one emergency power path 60 hours6.944444e-4 days 0.0167 hours 9.920635e-5 weeks 2.283e-5 months to OPERABLE status.

H. Both emergency power paths NOTE inoperable for unplanned reason TS 3.7.0 is not applicable when both other than Condition F. standby buses are energized by an OPERABLE Lee gas turbine.

H. 1 Energize two standby buses by an I hour OPERABLE Lee gas turbine. The 100kV transmission circuit shall be AND electrically separated from the system grid and all offsite loads. I hour from subsequent discovery of deenergized standby AND buses.

H.2 Verify by administrative means the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months operability status of:

Two offsite sources (TS 3.7.1),

Distribution Systems (TS 3.7.2),

EPSL (TSs 3.7.3, 3.7.4, 3.7.6), DC Sources (TS 3.7.8), and Vital Inverters (TS 3.7.9).

AND H.3 Restore inoperable components 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from discovery listed in H.2 to OPERABLE status. of inoperable component.

AND H.4 Restore one emergency power path 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months to OPERABLE status.

(continued)

Oconee Units 1, 2, & 3 3.7-6 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME I. One or more required offsite NOTE sources inoperable due to TS 3.7.0 is not applicable when both reasons other than Condition A standby buses are energized by an or B. OPERABLE Lee gas turbine.

1.1 Energize two standby buses by an I hour OPERABLE Lee gas turbine. The 100kV transmission circuit shall be AND electrically separated from the system grid and all offsite loads. I hour from subsequent discovery of deenergized standby AND buses.

1.2 Verify by administrative means the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months operability status of:

Two emergency power paths (TS 3.7.1), Distribution Systems (TS 3.7.2), EPSL (TSs 3.7.3-3.7.6),

DC Sources (TS 3.7.8), and Vital Inverters (TS 3.7.9).

AND 1.3 Restore inoperable components 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from discovery listed in 1.2 to OPERABLE status. of inoperable component.

AND 1.4 Restore required offsite sources to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months OPERABLE status.

(continued)

Oconee Units 1, 2, & 3 3.7-7 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

3.7.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME NOTE .NOTES Only applicable once in a three year 1. Keowee Hydro Unit generation to period for each Keowee Hydro Unit. the system grid prohibited except for test.

J. Overhead emergency power path 2. The OPERABLE Keowee Hydro inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months due to Unit may be made itioperable for 12 inoperable Keowee Hydro Unit. hours if required to restore both Keowee Hydro Units to OPERABLE status.

3. TS 3.7.0 is not applicable when both standby buses are energized by an OPERABLE Lee gas turbine.

J.1 Energize two standby buses by an Prerequisite OPERABLE Lee gas turbine. The 100kV transmission circuit shall be AND electrically separated from the system grid and all offsite loads. 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months from subsequent discovery of deenergized standby AND buses.

J.2 Verify by administrative means the Prerequisite operability status of: Two offsite sources and underground emergency power path (TS 3.7.1),

overhead emergency power path excluding Keowee Hydro Unit (TS 3.7.1), Distribution Systems (TS 3.7.2), EPSL (TSs 3.7.3-3.7.6),

DC Sources (TS 3.7.8), and Vital Inverters (TS 3.7.9).

AND J.3 Restore inoperable components 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from discovery listed in J.2 to OPERABLE status. of inoperable component.

(continued)

Oconee Units 1, 2, & 3 3.7-8 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME J. (continued) AND J.4 Perform SR 3.7.1.4. Once per 7 days AND J.5 Restore Keowee Hydro Unit to 42 days once in a 3 OPERABLE status. year period for each Keowee Hydro Unit.

K. Overhead emergency power path NOTE inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months due to TS 3.7.0 is not applicable when both inoperable Keowee Main Step- standby buses are energized by an up transformer. OPERABLE Lee gas turbine.

K. 1 Energize two standby buses by an Prerequisite OPERABLE Lee gas turbine. The 100kV transmission circuit shall be AND electrically separated from the system grid and all offsite loads. I hour from subsequent discovery of deenergized standby AND buses.

K.2 Verify by administrative means the Prerequisite operability status of: Two offsite sources and underground emergency power path (TS 3.7.1),

overhead Keowee Hydro Unit, Distribution Systems (TS 3.7.2),

EPSL (TSs 3.7.3-3.7.6), DC Sources (TS 3.7.8), and Vital Inverters (TS 3.7.9).

AND K.3 Restore inoperable components 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from discovery listed in K.2 to OPERABLE status. of inoperable component.

(continued)

Oconee Units 1, 2, & 3 3.7-9 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME K. (continued) AND K.4 Perform SR 3.7.1.4. Once per 7 days AND K.5 Restore Keowee Main Step-up 25 days transformer to OPERABLE status.

L. NOTE L. 1 Restore each trip circuit to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Separate Condition entry is OPERABLE status.

allowed for each breaker.

One trip circuit in one or both closed N breakers inoperable.

O OR One trip circuit in one or both closed SL breakers inoperable.

M. Required Actions and associated M.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times for Conditions C, F, G, H, I, J, K, or AND L not met.

M.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months OR Required Actions and associated Completion Times for Required Actions D. 1 or D.3 not met.

Oconee Units 1, 2, & 3 3.7-10 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 2 3 1 Unit 3

AC Sources - Operating 3.7.1 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.1.1 Perform SRs 3.7.8.1 (Float Voltage), 3.7.8.3 (Service Test), 3.7.8.4 As specified in the (Structural Surveillance), and 3.7.8.5 (Connection Surveillance) for applicable SRs.

the Keowee batteries.

SR 3.7.1.2 NOTES

1. Energizing standby buses is not required to be performed when standby buses are energized by an OPERABLE Lee gas turbine.

2. Not required to be met for the Keowee Hydro Unit associated with the overhead emergency power path when the overhead electrical disconnects for the Keowee Hydro Unit associated with the underground emergency power path are open.

Verify each Keowee Hydro Unit starts automatically and energizes Monthly the underground emergency power path.

SR 3.7.1.3 NOTE Only required to be met for the Keowee Hydro Unit associated with the overhead emergency power path.

Verify each Keowee Hydro Unit starts automatically and Monthly synchronizes with Yellow bus in 230 kV switchyard.

SR 3.7.1.4 NOTES

1. SR 3.7.1.2 may be performed in lieu of SR 3.7.1.4

2. Energizing standby buses is not required to be performed when standby buses are energized by an OPERABLE Lee gas turbine.

Verify Keowee Hydro Unit associated with underground emergency Monthly power path starts automatically and energizes the underground emergency power path.

(continued)

Oconee Units 1,2, & 3 3.7-11 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.7.1.5 NOTE-SR 3.7.1.3 may be performed in lieu of SR 3.7.1.5.

Verify Keowee Hydro Unit associated with overhead emergency Monthly power path starts automatically and synchronizes with Yellow bus in 230 kV switchyard.

SR 3.7.1.6 NOTES

1. Only required to be met when the associated breaker is closed.

2. Not required to be performed for SL breakers when overhead emergency power path is inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

Verify each N and SL breaker opens on an actual or simulated Monthly actuation signal.

SR 3.7.1.7 NOTE Not required to be performed for S breakers when overhead emergency power path is inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

Verify the S and E breakers are OPERABLE by full cycling. Monthly SR 3.7.1.8 Verify OPERABILITY of the Keowee underground feeder breaker Annually interlock and the underground to overhead ACB interlock.

SR 3.7.1.9 NOTE Only required to be met when a Lee gas turbine is energizing the standby buses.

Verify the dedicated 100kV line is OPERABLE by energizing both Annually standby buses by a Lee gas turbine.

SR 3.7.1.10 NOTE Only required to be met when a Lee gas turbine is energizing the standby buses.

Verify a Lee gas turbine can be started, placed on the system grid, Annually and supply the equivalent of a single Unit's maximum safeguard loads and two Unit's HOT SHUTDOWN loads on the system grid.

(continued)

Oconee Units 1, 2, & 3 3.7-12 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment =T Unit 3

AC Sources - Operating 3.7.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.7.1.11 Verify each Keowee Hydro Unit cai- Annually

1) Emergency start from each control room;

2) Attain rated speed and voltage within 23 seconds of an emergency start initiate;

3) Be synchronized to the grid and loaded at the maximum practical rate to a value equivalent to one Unit's safeguard loads plus two Unit's HOT SHUTDOWN loads.

SR 3.7.1.12 NOTE Not required to be met when the overhead electrical disconnects for the Keowee Hydro Unit associated with the underground emergency power path are open.

Verify the ability of the Keowee Unit ACBs to close automatically to Annually the underground path.

SR 3.7.1.13 NOTE Only required to be met when a Lee gas turbine is energizing the standby buses.

Verify that a Lee gas turbine can be started and connected to the 18 months isolated 100kV dedicated line and carry the equivalent of a single Unit's maximum safeguard loads within one hour.

SR 3.7.1.14 Perform an automatic transfer of the Main Feeder Buses to the 18 months Startup Transformer, Standby Buses, and retransfer to the Startup Transformers.

SR 3.7.1.15 NOTE Only required to be met during periods of commercial power generation using the Keowee Hydro Units.

Verify the ability of the Keowee Hydro units to supply emergency 18 months power from the initial condition of commercial power generation.

(continued)

Oconee Units 1, 2, & 3 3.7-13 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating 3.7.1 SURVELLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.7.1.16 NOTE Only required to be met during periods of commercial power generation using the Keowee Hydro Units.

Verify that the Keowee Hydro units load rejection response is 18 months bounded by the design criteria used to develop the Keowee operating restrictions.

SR 3.7.1.17 NOTES

1. Only required to be met when associated breaker is closed.

2. Not required to be performed for SL breakers when overhead emergency power path is inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

Verify each N and SL breaker opens on an actual or simulated 18 months actuation signal to each breaker trip circuit.

SR 3.7.1.18 NOTE Redundant breaker trip coils will be verified on a STAGGERED TEST BASIS.

Verify each 230 kV switchyard circuit breaker actuates to the correct 18 months position on an actual or simulated switchyard isolation actuation signal.

0 Oconee Units 1,2, & 3 3.7-14 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

Distribution Systems - Operating 3.7.2 3.7 ELECTRICAL POWER SYSTEMS 3.7.2 Distribution Systems - Operating TS 3.7.2 Distribution Systems shall be OPERABLE as follows:

1. Two energized main feeder buses each connected to two or more ES Power System Strings,

2. Three energized ES Power System Strings,

3. Four 125 VDC Vital I&C Power panelboards,

4. For Units 2 or 3, 125 VDC Vital I&C Power panelboards IDIC and IDID,

5. 230 kV switchyard DC Power panelboards DYA, DYB, DYC, DYE, DYF, and DYG, and

6. Four 120 VAC Vital Instrumentation Power panelboards.

APPLICABLITY: Above COLD SHUTDOWN ACTIONS CONDITION REQUIRED ACTION. COMPLETION TIME A. One main feeder bus inoperable. A. 1 Restore main feeder bus to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months OPERABLE status.

B. One ES Power System String B.1 Restore ES Power System String to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months inoperable. OPERABLE status.

C. One 125 VDC Vital I&C Power C.1 Restore 125 VDC Vital I&C Power 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months panelboard inoperable. panelboard to OPERABLE status.

D. NOTE D.1 Restore required 230 kV switchyard 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Separate Condition entry is DC Power panelboards to allowed for each 230 kV OPERABLE status.

switchyard DC Power panelboard.

One or more required 230 kV O switchyard DC Power panelboards inoperable.

(continued)

Oconee Units 1,2, & 3 3.7-15 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

Distribution Systems - Operating 3.7.2 ACTIONS (continued)

CONDITION . REQUIRED ACTION COMPLETION TIME E. -- --- NOTE-- - E. 1 Restore 125 VDC Vital I&C Power 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Condition E is not applicable to panelboards IDIC and IDID to Unit 1. OPERABLE status.

One 125 VDC Vital I&C Power panelboard required by LCO 3.7.2.4 inoperable.

F. KVIA or KVIB 120 VAC Vital F.1 Restore 120 VAC Vital 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months Instrumentation Power Instrumentation Power panelboard panelboard inoperable. to OPERABLE status.

G. KVIC or KVID 120 VAC Vital G.1 Restore 120 VAC Vital 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Instrumentation Power Instrumentation Power panelboard panelboard inoperable. to OPERABLE status.

H. Required Actions and associated H.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times not met.

AND H.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months (continued)

Oconee Units 1, 2, & 3 3.7-16 Amendment 232 Unit 1 Amendment232 Unit 2 Amendment Unit 3

Distribution Systems - Operating 3.7.2 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME I. Two or more main feeder buses, I.1 Enter TS 3,0 Immediately ES Power System Strings, 125 VDC Vital I&C Power panelboards, or 120 VAC Vital Instrumentation Power panelboards inoperable.

OR 230 kV switchyard DC Power panelboards DYA and DYE inoperable.

OR 230 kV switchyard DC Power panelboards DYB and DYF inoperable.

OR 230 kV switchyard DC Power panelboards DYC and DYG inoperable.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.2.1 Verify correct breaker alignments and voltage to required main 7 days feeder buses.

SR 3.7.2.2 Verify correct breaker alignments and voltage availability to required 7 days ES Power System Strings, 125 VDC Vital I&C Power panelboards, 230 kV switchyard DC Power panelboards, and 120 VAC Vital Instrumentation Power panelboards.

Oconee Units 1, 2, & 3 3.7-17 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Automatic Transfer Functions 3.7.3 3.7 ELECTRICAL POWER SYSTEMS 3.7.3 Emergency Power Switching Logic (EPSL) Automatic Transfer Functions TS 3.7.3 Two channels of the EPSL Automatic Transfer Function shall be OPERABLE.

APPLICABILITY: Above COLD SHUTDOWN ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One channel inoperable. A.1 Restore channel to OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months status.

B. Required Actions and associated B.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times not met.

AND B.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.3.1 Perform SR 3.7.1.14'(EPSL automatic transfer) As specified in applicable SR.

Oconee Units 1,2, & 3 3.7-18 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Voltage Sensing Circuits 3.7.4 90 3.7 ELECTRICAL POWER SYSTEMS 3.7.4 Emergency Power Switching Logic (EPSL) Voltage Sensing Circuits TS 3.7.4 Three channels of each of the following EPSL voltage sensing circuits shall be OPERABLE:

1. Startup Source;

2. Standby Bus 1;

3. Standby Bus 2;

4. Normal Source.

NOTE If both N breakers are open, Normal Source voltage sensing is not required.

APPLICABILITY: Above COLD SHUTDOWN ACTIONS NOTE Separate Condition entry is allowed for each inoperable Voltage Sensing Circuit.

CONDITION REQUIRED ACTION COMPLETION TIME A. One channel of one or more A.1 Restore channel to OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months circuits inoperable. status.

B. Required Actions and associated B.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times not met.

AND B.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.4.1 Perform a CHANNEL TEST 18 months Oconee Units 1, 2, & 3 3.7-19 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Keowee Emergency Start Function 3.7.5 3.7 ELECTRICAL POWER SYSTEMS 3.7.5 Emergency Power Switching Logic (EPSL) Keowee Emergency Start Function TS 3.7.5 Two channels of the EPSL Keowee Emergency Start Function shall be OPERABLE.

APPLICABILITY: Above COLD SHUTDOWN ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One channel inoperable. A.1 Restore channel to OPERABLE 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months status.

B. Required Actions and associated B.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times for Condition A not met. AND B.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months C. Two channels inoperable. C.1 Declare both Keowee Hydro Units Immediately inoperable for the affected Oconee Unit(s).

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.5.1 Perform SR 3.7.1.11 (Keowee emergency start) and SR 3.7.1.14 As specified in (EPSL automatic transfer). applicable SR.

Oconee Units 1, 2, & 3 3.7-20 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Degraded Grid Voltage Protection 3.7.6 3.7 ELECTRICAL POWER SYSTEMS, 3.7.6 Emergency Power Switching Logic (EPSL) Deraded Grid Voltage Protection TS 3.7.6 The following EPSL Degraded Grid Voltage Protection functions shall be OPERABLE:

1. Three Switchyard Degraded Grid Voltage Sensing Relays;

2. Two channels of Switchyard Degraded Grid Voltage Protection Actuation Logic.

APPLICABILITY: Above COLD SHUTDOWN ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One voltage sensing relay A.1 Place voltage sensing relay in trip. 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months inoperable.

B. One channel of actuation logic B.1 Restore channel to OPERABLE 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months inoperable. status.

C. Required Actions and associated C.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times not met for Conditions A or B. AND C.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months D. Two cr more voltage sensing D.1 Declare overhead emergency power Immediately relays inoperable. path inoperable.

OR Two actuation logic channels inoperable.

0 Oconee Units 1, 2, & 3 3.7-21 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Degraded Grid Voltage Protection 3.7.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.6.1 Perform a CHANNEL CALIBRATION of the voltage sensing 18 months channel with setpoint Allowable Value as follows:

Degraded voltage > 226 kV and < 229 kV with a time delay of 9 seconds + 1 second.

SR 3.7.6.2 Perform a CHANNEL TEST. 18 months Oconee Units 1,2, & 3 3.7-22 Amendment 232 Unit I Amendment 232 Unit 2 Amendment _____ Unit 3

EPSL CT-5 Degraded Grid Voltage Protection

.3.7.7 3.7 ELECTRICAL POWER SYSTEMS 3.7.7 Emergency Power Switching Logic (EPSL) CT-5 Degraded Grid Voltage Protection TS 3.7.7 The following EPSL CT-5 Degraded Grid Voltage Protection functions shall be OPERABLE:

1. Three CT-5 Degraded Grid Voltage Sensing Relays;

2. Two channels of CT-5 Degraded Grid Voltage Protection Actuation Logic.

APPLICABILITY: Above COLD SHUTDOWN when the Central switchyard is energizing the standby buses.

ACTIONS CONDTON REQUIRED ACTION COMPLETION TIME A. One voltage sensing relay A.1 Place voltage sensing relay in trip. 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months inoperable.

B. One channel of actuation logic B.1 Restore channel to OPERABLE 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months inoperable. status.

C. Two actuation logic channels C.1 Open SL breakers. I hour inoperable.

OR Two or more voltage sensing relays inoperable.

OR Required Actions and associated Completion Times cannot be met for Conditions A or B.

Oconee Units 1, 2, & 3 3.7-23 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL CT-5 Degraded Grid Voltage Protection 3.7.7 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.7.1 Perform a CHANNEL CALIBRATION of the voltage sensing 18 months channel with setpoint Allowable Value as fqllows:

a. Degraded voltage > 4143 V and < 4185 V with a time delay of 9 seconds + 1 second for the first level undervoltage inputs.

b. Degraded voltage > 3871 V and < 3901 V for the second level undervoltage inputs.

SR 3.7.7.2 Perform a CHANNEL TEST. 18 months 4

Oconee Units 1, 2, & 3 3.7-24 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

DC Sources - Operating 3.7.8

3.7 ELECTRICAL POWER SYSTEMS 3.7.8 DC Sources - Operating TS 3.7.8 DC Sources shall be OPERABLE as follows:

1. Three of four 125 VDC Vital I&C power sources,

2. Five of six 125 VDC Vital I&C power sources for operation of two or three Units,

3. Four of six 125 VDC Vital I&C power sources for operation of one Unit,

4. No single 125 VDC Vital I&C power source shall be the only source supplying power to two or more 125 VDC Vital I&C panelboards,

5. For Units 2 or 3, no single 125 VDC Vital I&C power source shall be the only source supplying power to 125 VDC Vital I&C panelboards IDIC and IDID, and

6. Two 230 kV switchyard 125 VDC power sources.

NOTES

1. The additional 125 VDC Vital I&C power sources required by LCO 3.7.8 part 2 or part 3 are not required to be connected to the Unit distribution system.

2. The 125 VDC Vital I&C power sources required by LCO 3.7.8 part 3 shall include one 125 VDC Vital I&C power sources belonging to each unit not above COLD SHUTDOWN.

APPLICABILITY: Above COLD SHUTDOWN ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One required 125 VDC Vital A.1 Restore required 125 VDC Vital 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months I&C power source inoperable to I&C power source to OPERABLE perform equalization charge after status.

performance test or service test.

B. One required 125 VDC Vital B.1 Restore required 125 VDC Vital 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months I&C power source inoperable for I&C power source to OPERABLE reasons other than Condition A. status.

(continued)

Oconee Units 1, 2, & 3 3.7-25 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

DC Sources - Operating

. 3.7.8 ONS (continued) 3.7.8 CONDITION REQUIRED ACTION COMPLETION TIME C. One 125 VDC Vital I&C power C.1 Align 125 VDC Vital I&C power 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months source supplying only source of sources such that no one 125 VDC power to two or more 125 VDC VitaFI&C power source is serving Vital I&C panelboards. as only power source to two or more 125 VDC Vital I&C panelboards.

D. NOTE D.1 Align 1 VDC Vital power 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Condition D is not applicable to sources such that no one 125 VDC Unit 1. Vital I&C power source is serving as only power source to 125 VDC One 125 VDC Vital I&C power Vital I&C panelboards IDIC and source supplying only source of IDID.

power to 125 VDC Vital I&C panelboards IDIC and VDDD.

E. One 230 kV switchyard 125 E.1. Restore 230 kV switchyard 125 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months VDC power source inoperable to VDC power source to OPERABLE perform equalization charge status.

performance test or service aafter test.

F. One 230 kV switchyard 125 F.1 Restore 230 kV switchyard 125 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months VDC power source inoperable VDC power source to OPERABLE for reasons other than Condition status.

E.

G. Required Actions and associated G.1 Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times not met.

AND G.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months H. Two or more required 125 VDC H.1 Enter TS 3.0 Immediately Vital I&C power sources inoperable.

OR Two 230 kV switchyard 125 VDC power sources inoperable.

Oconee Units 1, 2, & 3 3.7-26 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

DC Sources - Operating 3.7.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.8.1 Verify battery float voltage > 125VDC Weekly SR 3.7.8.2 Verify peak inverse voltage capability of each 125 VDC Vital I&C 6 Months auctioneering diode is within limits.

SR 3.7.8.3 Verify battery capacity is adequate to supply and maintain in Annually OPERABLE status the required emergency loads for the design duty cycle when the battery is subjected to a battery service test.

SR 3.7.8.4 Verify cells, end cell plates, and battery racks show no visual Annually indication of structural damage or degradation.

SR 3.7.8.5 Verify cell to cell and terminal connections are clean, tight, and Annually coated with anti-corrosion grease.

Oconee Units 1,2, & 3 3.7-27 Amendment Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

Vital Inverters - Operating 3.7.9 3.7 ELECTRICAL POWER SYSTEMS 3.7.9 Vital Inverters - Operating TS 3.7.9 Four vital inverters shall be OPERABLE.

APPLICABILITY: Above COLD SHUTDOWN ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. DIA or DIB inverter inoperable. A.1 Connect associated panelboard to 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months regulated panelboard KRA.

AND A.2 Verify associated panelboard is Once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months energized.

AND 7 days A.3 Restore vital inverter to OPERABLE status.

B. DIC or DID inverter inoperable. B.1 Connect associated panelboard to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months regulated panelboard KRA.

AND B.2 Verify associated panelboard is Once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months energized.

AND 7 days B.3 Restore vital inverter to OPERABLE status.

(continued)

Oconee Units 1, 2, & 3 3.7-28 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

Vital Inverters - Operating 3.7.9 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. Required Actions and associated C.l Be in HOT SHUTDOWN 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Times not met.

AND C.2 Be in COLD SHUTDOWN 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months D. Two or more vital inverters D. 1 Enter TS 3.0 Immediately inoperable.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.9.1 Verify correct vital inverter voltage, frequency, and alignment to Weekly required 120 VAC Vital Instrumentation Power panelboards.

Oconee Units 1, 2, & 3 3.7-29 Amendment . Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

Battery Cell Parameters 3.7.10 3.7 ELECTRICAL POWER SYSTEMS 3.7.10 Battery Cell Parameters TS 3.7.10 Battery cell parameters for the Keowee Hydro Unit, 125 VDC Vital I&C, and 230 kV 125 VDC switchyard batteries shall be within the limits of Table 3.7.10-1.

APPLICABILITY: When associated DC power sources are required to be OPERABLE.

ACTIONS NOTES

1. Separate Condition entry is allowed for each battery.

2. TS 3.7.0 does not apply.

CONDITION REQUIRED ACTION COMPLETION TIME A. One or more batteries with one A.1 Verify pilot cell electrolyte level I hour or more battery cell parameters and float voltage meet Table not within Category A or B 3.7.10-1 Category C values.

limits.

AND A.2 Verify battery cell parameters meet 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Table 3.7. 10-1 Category C values.

AND Once per 7 days AND thereafter A.3 Restore battery cell parameters to 90 days Category A and B limits of Table 3.7.10-1.

B. Required Action and associated B.1 Declare associated battery Immediately Completion Time of Condition inoperable.

A not met.

OR One or more batteries with average electrolyte temperature of the representative cells

< 60*F.

OR One or more batteries with one or more battery cell parameters not within Category C values.

Oconee Units 1, 2, & 3 3.7-30 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

Battery Cell Parameters 3.7.10 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.10.1 Verify battery cell parameters meet Table 3.7.10-1 Category A Weekly limits.

SR 3.7.10.2 Verify battery cell parameters meet Table 3.7.10-1 Category B Quarterly limits.

SR 3.7.10.3 Verify average electrolyte temperature of representative cells is Quarterly

> 60'F.

Oconee Units 1, 2, & 3 3.7-31 Amendment 232 Unit I Amendment Z32. Unit 2 Amendment .2. Unit 3

Battery Cell Parameters 3.7.10 Table 3.7.10-1 (page 1 of 1)

Battery Cell Surveillance Requirements PARAMETER CATEGORY A: CATEGORY B: CATEGORY C:

LIMITS FOR EACH LIMITS FOR EACH ALLOWABLE DESIGNATED PILOT CONNECTED CELL LIMITS FOR EACH CELL CONNECTED CELL Electrolyte Level > Minimum level > Minimum level Above top of plates, indication mark, and indication mark, and and not overflowing

<14 inch above <% inch above maximum level maximum level indication mark(a) indication mark(a)

Float Voltage > 2.13 V > 2.13 V > 2.07 V Specific Gravity(b)(c) > 1.200 > 1.200 > 1.200 AND Not more than 0.0 10 below average of all connected cells (a) It is acceptable for the electrolyte level to temporarily increase above the specified maximum during equalizing charges provided it is not overflowing.

(b) Corrected for electrolyte temperature and level. Level correction is not required, however, when battery float current is < 2 amps when on float charge.

(c) A battery float current of < 2 amps when on float charge is acceptable for meeting specific gravity limits following a battery recharge, for a maximum of 7 days. When float current is used in lieu of specific gravity requirements, specific gravity of each connected cell shall be measured prior to expiration of the 7 day allowance.

Oconee Units 1, 2, & 3 3.7-32 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment Unit 3

AC Sources - Operating B 3.7.1 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.1 AC Sources - Operating BASES BACKGROUND The AC Power System consists of the offsite power sources (preferred power) and the onsite standby power sources (Keowee Hydro Units). This system is designed to supply the required engineered safety features (ESF) loads of one unit and safe shutdown loads of the other two units and is so arranged that no single failure can disable enough loads to jeopardize plant safety. In accordance with the intent of proposed Atomic Energy Commission (AEC) general design criterion 39, the design of the AC Power System provides independence and redundancy to ensure an available source of power to the ESF systems (FSAR 3.1.39). The Keowee Hydro turbine generators are powered through a common penstock by water taken from Lake Keowee. The use of a common penstock is justified on the basis of past hydro plant experience of the licensee (since 1919) which indicates that the cumulative need to dewater the penstock can be expected to be limited to about one day a year, principally for inspection, plus perhaps four days every tenth year.

The preferred power source is provided from offsite power to the red or yellow bus in the 230kV switchyard to the units startup transformer and the E breakers. The 230kV switchyard is electrically connected to the 525kV switchyard via the autobank transformer. The standby buses may receive offsite power from the 100kV transmission system through CT-5 and the SL breakers. The two emergency power paths are the overhead path and the underground path. The underground emergency power path is from one Keowee Hydro Unit through the S breakers. The overhead emergency power path is from the other Keowee Hydro Unit through the E breakers. In addition to supplying emergency power for Oconee, the Keowee Hydro Units provide peaking power to the licensee's generation system. During periods of commercial power generation, the Keowee Hydro Units are operated within the acceptable region of the Keowee Hydro operating restrictions. This will ensure that the Keowee Hydro Units will be able to perform their emergency power functions from an initial condition of commercial power generation. The Keowee Hydro operating restrictions for commercial power generation are contained in the Selected Licensee Commitment manual. Changes to these operating restrictions would be performed in accordance with 10 CFR 50.59, which would include an evaluation to determine if any unreviewed safety questions exist.

The standby buses can also receive power from a combustion turbine generator at the Lee Steam Station through a dedicated 100kV transmission line, transformer CT-5, and both SL breakers. The 100kV transmission line is electrically separated from the system grid and offsite loads. This source is required to be OPERABLE only when specified in TS 3.7.1 and is considered to be an onsite power source in this mode of operation.

The auxiliaries of two units in HOT SHUTDOWN plus the auxiliaries of the one unit with a LOCA require a total AC power capacity as shown in FSAR Table 8-1.

(continued)

Oconee Units 1,2, & 3 B 3.7-1 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

BACKGROUND The continuous AC power capacity available to the Oconee Units is:

(continued)

Source Capacity Underground emergency power path 22.4MVA (limited by transformer CT-4)

Overhead emergency power path 30MVA (limited by transformer CT-1, CT-2, or CT-3)

Offsite sources from 230kV switchyard 30MVA (limited by transformer CT-1, CT-2, or CT-3)

Offsite source from the Central 100kV switchyard 22.4MVA (limited by transformer CT-5)

Backup 100kV transmission line from Lee Station Gas 22.4MVA Turbine Generator (limited by transformer CT-5)

Thus, the minimum available capacity from any one of the multiple sources of AC power, 22.4MVA, is adequate.

APPLICABLE The initial conditions of design basis transient and accident analyses in the FSAR SAFETY Chapter 6 (Engineered Safeguards) and 15 (Accident Analyses) assume all ESF ANALYSES systems are OPERABLE. The AC power system is designed to provide sufficient capacity, capability, redundancy, and reliability to ensure the availability of necessary power to ESF systems so that the fuel, reactor coolant system, and containment design limits are not exceeded. These limits are discussed in more detail in the Bases for other TS's.

Consistent with the accident analysis assumptions of a LOOP and a single failure of one onsite emergency power path, two of the onsite emergency power sources are required to be OPERABLE.

AC Sources - Operating is a system that is part of the primary success path and functions to mitigate a DBA or transient that presents a challenge to the integrity of a fission product barrier. As such, AC Sources - Operating satisfies the requirements of Selection Criterion 3 of 10 CFR 50.36 (Ref. 1).

(continued)

Oconee Units 1,2, & 3 B 3.7-2 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 2Z Unit 3

AC Sources - Operating B 3.7.1 ASES (continued)

TS The basic design criteria of the entire emergency electric power system of a nuclear unit, including the generating sources, distribution system and controls, is that a single failure of any component passive or active will not preclude the system from supplying emergency power when required,(Ref 5).

Overhead Emergency Power Path If closed, each N breaker must be capable of opening using either of its associated breaker trip circuits. Either of the following combinations provide an acceptable overhead emergency power path.

1A) Keowee Unit 1 generator, LB) Keowee Unit 2 generator, 2A) Keowee ACB 1,* 2B) Keowee ACB 2,*

3A) Keowee auxiliary 3B) Keowee auxiliary transformer LX, Keowee transformer 2X, Keowee ACB 5, Keowee Load ACB 6, Keowee Load Center LX, Center 2X, 4A) Keowee MCC 1XA, 4B) Keowee MCC 2XA, 5A) Keowee Battery #1, 5B) Keowee Battery #2, Charger #1 or Standby Charger #2 or Standby Charger, and Distribution Charger, and Distribution center IDA, Center 2DA, 6A) Keowee Unit 1 interlocks 6B) Keowee Unit 2 interlocks between overhead and between overhead and underground emergency underground emergency power path breakers, power path breakers,

7) Keowee reservoir level > 775 feet above sea level,

8) Keowee main step-up transformer,

9) Zone overlap circuitry,

10) PCB 9,*

11) The 230kV switchyard yellow bus capable of being isolated by one channel of Switchyard Isolate from Degraded Grid Voltage Protection circuitry,

12) A unit startup transformer and associated yellow bus PCB (CT-1

/ PCB 18, CT-2 / PCB 27, CT-3 / PCB 30), and

13) Both E breakers.

Enabled by one channel of Switchyard Isolate Complete.

(continued)

Oconee Units 1, 2, & 3 B 3.7-3 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 ASES (continued)

TS (continued) Underground Emergency Power Path If closed, each N breaker and each SL breaker must be capable of opening using either of its associated breaker trip.circuits. Either of the following combinations provide an acceptable underground emergency power path.

IA) Keowee Unit I generator, IB) Keowee Unit 2 generator, 2A) Keowee ACB 3, 2B) Keowee ACB 4, 3A.1) Keowee auxiliary 3B.1) Keowee auxiliary transformer C , Keowee transformer CX, Keowee ACB 7, Keowee Load ACB 8, Keowee Load Center IX, Center 2X, 3A.2) One Oconee Unit I S 3B.2) One Oconee Unit 1 S breaker capable of feeding breaker capable of feeding switchgear ITC, switchgear 1TC, 3A.3) Switchgear ITC capable 3B.3) Switchgear 1TC capable of feeding Keowee of feeding Keowee auxiliary transformer CX, auxiliary transformer CX, 4A) Keowee MCC IXA, 4B) Keowee MCC 2XA, 5A) Keowee Battery #1, 5B) Keowee Battery #2, Charger #1 or Standby Charger #2 or Standby Charger, and Distribution Charger, and Distribution Center IDA, Center 2DA, 6A) Keowee Unit 1 interlocks 6B) Keowee Unit 2 interlocks between overhead and between overhead and underground emergency underground emergency power path breakers, power path breakers,

7) Keowee reservoir level >775 feet above sea level,

8) The underground feeder,

9) Interlocks between underground emergency power path breakers,

10) Transformer CT-4,

11) Both SK breakers,

12) Both standby buses, and

13) Both S breakers.

Offsite Sources The two offsite sources are required to be "physically independent" (separate towers) prior to entering the 230kV switchyard. Once the 230kV lines enter the switchyard, an electrical pathway must exist through operable PCBs and disconnects such that both sources are available to energize the Unit's startup transformer either automatically or with operator action. Once within the boundary of the switchyard the electrical pathway may be the same for both independent offsite sources. In addition, at least one E breaker must be available to automatically supply power to the main feeder buses from the (continued)

Oconee Units 1, 2, & 3 B 3.7-4 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

TS (continued) Offsite Sources (continued) energized startup transformer. If both E breakers are inoperable, then neither the 230kV sources nor the overhead emergency power path can energize the main feeder buses, therefore, the startup transformer is considered to be inoperable. The voltage provided to the startup transformer by the two independent offsite sources must be sufficient to ensure all engineered safeguard equipment will operate (Ref. 3). Two of the following offsite sources are required:

1) Jocassee (from Jocassee) Black or White,

2) Dacus (from North Greenville) Black or White,

3) Oconee (from Central) Black or White,

4) Calhoun (from Central) Black or White,

5) Autobank transformer fed from either the Asbury (from Newport),

Norcross (from Georgia Power), or Katoma (from McGuire) 525kV line.

Lee Gas Turbine During specific conditions in TS 3.7.1, one Lee gas turbine is required to be OPERABLE and is connected to the standby buses through a dedicated 100kV transmission line. The dedicated 100kV transmission line is electrically separated from the system grid and offsite loads. Operation and connection of a Lee gas turbine to the standby buses requires operator action.

This Technical Specification is modified by three NOTES. NOTE 1 indicates the underground emergency power path associated with the Keowee Hydro Unit which is selected to the overhead emergency power path is not required to be OPERABLE when the electrical disconnects for the Keowee Hydro Unit selected to the underground emergency power path are open. When these disconnects are open, a fault in the zone overlap region will not disable both Keowee Hydro Units. NOTE 2 indicates the Lee gas turbine is only required to be OPERABLE when the standby buses are required to be energized from an OPERABLE Lee gas turbine. The standby buses are required to be energized from an OPERABLE Lee gas turbine when:

a) the underground emergency power path is inoperable > 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , b) the overhead Keowee Hydro Unit is inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , c) the Keowee Main Step-up transformer is inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , d) both emergency power paths are inoperable for planned reasons, e) both emergency power paths are inoperable for unplanned reasons for >

1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , f) one or more required offsite sources are inoperable > 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

(continued)

Oconee Units 1, 2, & 3 B 3.7-5 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

TS (continued) NOTE 3 indicates that the operability of the Keowee Hydro Units during periods of commercial power generation is based on lake levels and the power level of the Keowee Hydro Units. The operating restrictions are contained in the Selected Licensee Commitment manual which is Chapter 16 of the ONS FSAR.

APPLICABILITY The AC power sources for ESF systems are required to be OPERABLE above COLD SHUTDOWN to ensure that:

I. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of anticipated operational occurrences or abnormal transients, and

2. Adequate core cooling is provided, and containment integrity and other vital functions are maintained in the event of a postulated DBA.

ACTIONS The Required Actions have been established based on the level of degradation of the power sources.

A.1, A.2, and A.3 In the event a startup transformer becomes inoperable, it effectively causes one of the emergency power paths (overhead path) and both of the offsite sources to be inoperable.

One emergency power path remains available through the underground feeder to ensure safe shutdown of the unit in the event of a transient or accident without a single failure.

Operation may continue for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months if the availability of the underground emergency power path is demonstrated within I hour. This Required Action provides assurance that no previously undetected failures have occurred in the underground emergency power path. If available, another Unit's startup transformer should be aligned to supply power to the affected Unit's auxiliaries so that offsite power sources and the overhead path will also be available if needed. Although this alignment restores the availability of the offsite sources and overhead emergency power path, the shared startup transformer's capacity and voltage adequacy could be challenged under certain DBA conditions. The shared alignment is acceptable because the preferred mode of Unit shutdown is with reactor coolant pumps providing forced circulation and due to the low likelihood of an event challenging the capacity of the shared transformer during a 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months period to bring a Unit to COLD SHUTDOWN. Required Action A.3 allows the option of designating an OPERABLE startup transformer from another Unit. For example, if Unit I and 2 are operating and CT-2 becomes inoperable, Unit 2 may align CT-I to the Unit 2 main (continued)

Oconee Units 1, 2, & 3 B 3.7-6 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

ACTIONS A.1, A.2, and A.3 (continued) feeder buses and continue operating for up to 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . At that time either CT-2 must be restored to OPERABLE status or CT-I must be "designated" to one Unit. Once CT-I has been designated to a Unit, the other Unit must begin shutting down per Condition B.

Note that one Unit above COLD SHUTDOWN and a Unit in COLD SHUTDOWN may share a startup transformer indefinitely provided that the loads on the COLD SHUTDOWN Unit are maintained within acceptable limits (Ref. 2). For example, if Unit 1 is already in COLD SHUTDOWN and CT-2 becomes inoperable, Unit 2 may align CT-I to the Unit 2 main feeder buses and continue operation indefinitely.

Restoration of the inoperable startup transformer to an OPERABLE status allows the affected Oconee Unit to exit this Condition.

B.1 and B.2 In the event a shared startup transformer has been designated to one Unit per Required Action A.3, the Unit without a startup transformer must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in another 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months since the shared startup transformer's capacity could be challenged under certain DBA conditions. In addition, if the Required Actions and associated Completion Times for Condition A cannot be met, the Unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in another 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . These times allow for a controlled shutdown without placing undue stress on plant operators or plant systems.

C.1 and C.2 When the overhead emergency power path is inoperable due to reasons other than Condition A or B and the underground emergency power path is operable, sufficient AC power sources remain available to ensure safe shutdown of the unit in the event of a transient or accident. Operation could safely continue for 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months if the operability of the underground emergency power path is demonstrated within I hour and every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter. This demonstration is to assure that the underground emergency power path is not inoperable due to a common cause or due to an undetected failure. When the standby buses are energized by an OPERABLE Lee gas turbine, the likelihood that the OPERABLE emergency power path will be required is decreased, thus testing on a 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months frequency is no longer necessary. Testing on a 7 day frequency will be commenced if Condition J or K is entered. If the inoperable emergency power path is not restored to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , a controlled shutdown must be initiated per Condition M or the Required Actions of Condition J or K must be completed for the inoperable Keowee Hydro Unit or Keowee Main Step-up transformer. A NOTE has been included to specify that Required Actions J.I or K. 1 (Lee on the standby buses) and J.2 or K.2 (verification of operability) must be completed prior to exceeding 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

(continued)

Oconee Units 1, 2, & 3 B 3.7-7 Amendment 232 Unit I Amendment 232 Unit 2 Amendment Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

ACTIONS D.1, D.2, and D.3 With the underground emergency power path inoperable and the overhead emergency power path operable, sufficient AC power sources remain available to ensure safe shutdown of the unit in the event of a transient or accident. Operation could safely continue for 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months if the operability of the overhead emergency power path is demonstrated within I hour and every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter. This demonstration is to assure that the overhead emergency power path is not inoperable due to a common cause or due to an undetected failure. When the standby buses are energized by an OPERABLE Lee gas turbine, the likelihood that the OPERABLE emergency power path will be required is decreased, thus testing on a 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months frequency is no longer necessary.

For outages of the underground power path in excess of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , a Lee gas turbine must energize a standby bus prior to the outage exceeding 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . This ensures the availability of a power source on the standby buses while the underground power path is out of service in excess of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

E.1 and E.2 If the underground power path is out of service due to reasons that prevent energization of a standby bus from an OPERABLE Lee gas turbine, then the underground power path shall not be out of service for more than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months and a controlled shutdown will be initiated per Condition E once the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months period is exceeded.

F. I With an E breaker and S breaker inoperable on the same main feeder bus the affected main feeder bus cannot receive power from either on-site emergency power source. In this case, the affected main feeder bus must be declared inoperable. Appropriate Required Actions are specified in TS 3.7.2 (Distribution Systems - Operating). Both on site emergency power paths are considered OPERABLE in this case since, without a single failure, both on-site emergency paths can provide power to the remaining main feeder bus.

(continued)

Oconee Units 1, 2, & 3 B 3.7-8 Amendment 232 Unit 1 Amendment _Z2- Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

ACTIONS G.1 through G.4 With both emergency on-site power paths inoperable for planned reason other than Condition F, insufficient standby AC power sources are available to feed the minimum required ESF functions. The offsite power system is the only source of AC power available for this level of degradation. Operation with both Keowee units inoperable for planned reason other than Condition F is permitted for 60 hours6.944444e-4 days 0.0167 hours 9.920635e-5 weeks 2.283e-5 months provided that the actions detailed below are taken prior to removing both Keowee Hydro Units from service.

Further, with the exception of Lee energizing the standby buses, in the event these actions are not met during the inoperability of both emergency power paths, a period of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed by Required Action G.3 to restore the inoperable component. For example if both Keowee Units have been inoperable 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months and one channel of load shed (required by TS 3.7.3) is discovered to-be inoperable, the channel must be restored to OPERABLE status within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

1. The standby buses are continuously energized by an OPERABLE Lee gas turbine through the 100kV transmission circuit. The 100kV transmission circuit shall be electrically separated from the system grid and all offsite loads. This arrangement provides a high degree of reliability for the emergency power system. In this configuration, the Lee gas turbine is serving as an onsite emergency power source, however since the Oconee Units are vulnerable to single failure of the 100kV transmission circuit a time limit of 60 hours6.944444e-4 days 0.0167 hours 9.920635e-5 weeks 2.283e-5 months is imposed. Required Action G. I permits the standby buses to be re-energized by an OPERABLE Lee gas turbine within I hour in the event this source is lost.

For example if both Keowee Units have been inoperable 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and the Lee gas turbine feeding the 100kV line trips, the 100kV line must be re-energized from an OPERABLE Lee gas turbine within the next hour.

2. Two offsite sources are verified and maintained OPERABLE by complying with TS 3.7.1. This Required Action provides additional assurance that offsite power will be available while both Keowee Units are inoperable.

3. Distribution Systems are verified and maintained OPERABLE by complying with TS 3.7.2. This Required Action increases the probability that power will be available to ESF equipment even in the unlikely event of a single failure unrelated to the inoperability of both emergency power paths.

4. EPSL with the exception of the Keowee Emergency Start Function (TS 3.7.5) is verified and maintained OPERABLE by complying with TSs 3.7.3, 3.7.4, and 3.7.6. This Required Action increases the probability that EPSL will function as required even in the unlikely event of a single failure unrelated to the inoperability of both emergency power paths.

(continued)

Oconee Units 1, 2, & 3 B 3.7-9 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

ACTIONS G. 1 through G.4 (continued)

5. DC Sources are verified and maintained OPERABLE by complying with TS 3.7.8. This Required Action increases the probability that the DC Sources will function as required to.support EPSL even in the unlikely event of a single failure unrelated to inoperability of both emergency power paths.

6. Vital Inverters are verified and maintained OPERABLE by complying with TS 3.7.9. This Required Action increases the probability that the vital instrumentation inverters will function as required to support EPSL even in the unlikely event of a single failure unrelated to the inoperability of both emergency power paths.

The term verify as used in these Required Actions allows for an administrative check by examining logs or other information to determine if the required equipment is inoperable for maintenance or other reasons. It does not require unique performance of Surveillance Requirements needed to demonstrate operability of the equipment. In addition, a planned outage of both Keowee Hydro Units consists of outages where an OPERABLE Lee gas turbine can energize the standby buses prior to the removal of the Keowee Hydro Units from service.

If both Keowee units are restored, unrestricted operation may continue. If only one unit is restored within 60 hours6.944444e-4 days 0.0167 hours 9.920635e-5 weeks 2.283e-5 months , operation may continue per the Required Actions of Condition C, D or G.

The Required Actions have been modified by a NOTE which provides an exception to TS 3.7.0 when an OPERABLE Lee gas turbine is energizing the standby buses as required by TS 3.7.1. This exception allows the Unit to heat up above COLD SHUTDOWN when both emergency power paths are inoperable.

H.1 through H.3 With both emergency on-site power paths inoperable for an unplanned reason other than Condition F, insufficient standby AC power sources are available to feed the minimum required ESF functions. The offsite power system is the only source of AC power available for this level of degradation. The risk associated with continued operation for one hour without an emergency power source is considered acceptable due to the low likelihood of a LOOP during this time period, and because of the potential for grid instability caused by the simultaneous shutdown of all three units. This instability would increase the probability of a total loss of AC power. Operation with both Keowee units inoperable due to an unplanned outage other than condition F is permitted for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (continued)

Oconee Units 1, 2, & 3 B 3.7-10 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

. BASES (continued)

AC Sources - Operating B 3.7.1 H.1 through H.3 (continued) provided that the actions detailed below are taken prior to exceeding one hour. Further, with the exception of Lee energizing the standby buses, in the event these actions are not met during the inoperability of both emergency power paths, a period of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed by Required Action H.3 to restore the inoperable component. For example if both Keowee Units have been inoperable 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and one channel of load shed (required by TS 3.7.3) is discovered to be inoperable, the channel must be restored to OPERABLE status within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

1. The standby buses are continuously energized by an OPERABLE Lee gas turbine through the 100kV transmission circuit. The 100kV transmission circuit shall be electrically separated from the system grid and all offsite loads. This arrangement provides a high degree of reliability for the emergency power system. In this configuration, the Lee gas turbine is serving as an onsite emergency power source, however since the Oconee Units are vulnerable to single failure of the 100kV transmission circuit a time limit of 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is imposed. Required Action H. 1 permits the standby buses to be re-energized by an OPERABLE Lee gas turbine within I hour in the event this source is lost.

For example if both Keowee Units have been inoperable 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months and the Lee gas turbine feeding the 100kV line trips, the 100kV line must be re-energized from an OPERABLE Lee gas turbine within the next hour.

2. Two offsite sources are verified and maintained OPERABLE by complying with TS 3.7.1. This Required Action provides additional assurance that offsite power will be available while both Keowee Units are inoperable.

3. Distribution Systems are verified and maintained OPERABLE by complying with TS 3.7.2. This Required Action increases the probability that power will be available to ESF equipment even in the unlikely event of a single failure unrelated to the inoperability of both emergency power paths.

4. EPSL with the exception of the Keowee Emergency Start Function (TS 3.7.5) is verified and maintained OPERABLE by complying with TSs 3.7.3, 3.7.4, and 3.7.6. This Required Action increases the probability that EPSL will function as required even in the unlikely event of a single failure unrelated to the inoperability of both emergency power paths.

5. DC Sources are verified and maintained OPERABLE by complying with TS 3.7.8. This Required Action increases the probability that the DC Sources will function as required to support EPSL even in the unlikely event of a single failure unrelated to inoperability of both emergency power paths.

(continued)

Oconee Units 1, 2, & 3 B 3.7-11 Amendment -23?- Unit I Amendment _23. Unit 2 Amendment _23.1 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

H.1 through H.3 (continued)

6. Vital Inverters are verified and maintained OPERABLE by complying with TS 3.7.9. This Required Action increases the probability that the vital instrumentation inverters will function as required to support EPSL even in the unlikely event of a single failure unrelated to the inoperability of both emergency power paths.

The term verify as used in these Required Actions allows for an administrative check by examining logs or other information to determine if the required equipment is inoperable for maintenance or other reasons. It does not require unique performance of Surveillance Requirements needed to demonstrate operability of the equipment. In addition, an unplanned outage of both Keowee Hydro Units consists of outages where an OPERABLE Lee gas turbine cannot be placed on the standby buses prior to the removal of the Keowee Hydro Units from service.

If both Keowee units are restored, unrestricted operation may continue. If only one unit is restored within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , operation may continue per the Required Actions of Condition C, D or H.

The Required Actions have been modified by a NOTE which provides an exception to TS 3.7.0 when an OPERABLE Lee gas turbine is energizing the standby buses as required by TS 3.7.1. This exception allows the Unit to heat up above COLD SHUTDOWN when both emergency power paths are inoperable.

1.1 through 1.4 With all of the required offsite sources inoperable due to degraded grid, loss of voltage, or other causes, sufficient standby AC power sources are available to maintain the unit in a safe shutdown condition in the event of a DBA. However, since the AC power system is degraded below the TS requirements, a time limit on continued operation is imposed.

With only one of the required offsite sources OPERABLE, the likelihood of LOOP is increased such that the same Required Actions for all required offsite sources inoperable are conservatively followed. The risk associated with continued operation for one hour without a Lee gas turbine energizing the standby buses is considered acceptable due to the low likelihood of a failure of both emergency power paths during this time period, and because of the potential for grid instability caused by the simultaneous shutdown of all three units. Operation with the available offsite sources less than required by the TS is permitted for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months provided that the actions detailed below are taken prior to exceeding one hour. Further, with the exception of Lee energizing the standby buses, in the event these actions are not met during the inoperability of the required offsite sources, a period of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed by Required Action 1.3 to restore the (continued)

Oconee Units 1, 2, & 3 B 3.7-12 Amendment .23Z Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

ACTIONS 1.1 through 1.4 (continued) inoperable component. For example if both required offsite sources have been inoperable 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and one channel of load shed (required by TS 3.7.3) is discovered to be inoperable, the channel must be restored to OPERABLE status within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

1. The standby buses are continuously energized by an OPERABLE Lee gas turbine through the 100kV transmission circuit. The 100kV transmission circuit shall be electrically separated from the system grid and all offsite loads. This arrangement provides a high degree of reliability for the emergency power system. In this configuration, the Lee gas turbine is serving as an onsite emergency power source. Required Action 1.1 permits the standby buses to be reenergized by an OPERABLE Lee gas turbine within I hour in the event this source is lost. For example, if both required offsite sources have been inoperable 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and the Lee gas turbine feeding the 100kV line trips, the 100kV line must be reenergized from an OPERABLE Lee gas turbine within the next hour.

2. Two emergency power paths are verified and maintained OPERABLE by complying with TS 3.7.1. This Required Action provides additional assurance that the emergency power paths will be available if required while the required offsite sources are inoperable.

3. Distribution Systems are verified and maintained OPERABLE by complying with TS 3.7.2. This Required Action increases the probability that power will be available to ESF equipment even in the unlikely event of a single failure unrelated to the inoperability of the required offsite sources.

4. EPSL is verified and maintained OPERABLE by complying with TSs 3.7.3, 3.7.4, 3.7.5, and 3.7.6. This Required Action increases the probability that EPSL will function as required even in the unlikely event of a single failure unrelated to the inoperability of the required offsite sources.

5. DC Sources are verified and maintained OPERABLE by complying with TS 3.7.8. This Required Action increases the probability that the DC Sources will function as required to support EPSL even in the unlikely event of a single failure unrelated to inoperability of the required offsite sources.

6. Vital Inverters are verified and maintained OPERABLE by complying with TS 3.7.9. This Required Action increases the probability that the vital instrumentation inverters will function as required to support EPSL even in the unlikely event of a single failure unrelated to the inoperability of the required offsite sources.

(continued)

--Oconee Units 1, 2, & 3 B 3.7-13 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 ASES (continued)

ACTIONS 1.1 through 1.4 (continued)

The term verify as used in these Required Actions allows for an administrative check by examining logs or other information to determine if the required equipment is inoperable for maintenance or other reasons. It does not require unique performance of Surveillance Requirements needed to demonstrate operability of the equipment If two offsite sources are restored within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , unrestricted operation may continue.

The Required Actions have been modified by a NOTE which provides an exception to TS 3.7.0 when an OPERABLE Lee gas turbine is energizing the standby buses as required by TS 3.7.1. This exception allows the Unit to heat up above COLD SHUTDOWN when one or more required offsite sources are inoperable due to reasons other than Condition A or B.

J.1 through J.5 Condition J has been established to allow maintenance and repair of a Keowee Hydro Unit which requires longer than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . This Condition is modified by a NOTE which indicates the Condition is applicable once in a three year period for each Keowee Hydro Unit. A "Keowee Hydro Unit" is considered to be all components between ACBs 1, 2, 3, and 4, as well as all components between auxiliary transformer CX and the Keowee Main step-up transformer. The primary long term maintenance items are expected to be hydro turbine runner and discharge ring welding repairs which are estimated to be necessary every six to eight years. Also, generator thrust and guide bearing replacements will be necessary. Other items which manifest as failures are expected to be extremely rare and could possibly be performed during the permitted maintenance periods. A time period of up to 45 days for each Keowee Hydro unit is permitted every three years. The 3 days from Condition C are added to the 42 day Completion Time in Condition J to get the 45 day time period.

The Required Actions for the special inoperability period have been modified by three NOTES. NOTE 1 prohibits generation to the system grid except for testing. This restriction limits the number of possible failures which could cause loss of the underground emergency power path. NOTE 2 allows the OPERABLE Keowee Hydro Unit to be made inoperable for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months if required to restore both Keowee Hydro Units to OPERABLE status. This note is necessary since certain actions such as dewatering the penstock may be necessary to restore the inoperable Keowee Hydro Unit although these actions would also cause both Keowee Hydro Units to be inoperable. NOTE 3 provides an exception to TS 3.7.0 when an OPERABLE Lee gas turbine is energizing the standby buses as required by TS 3.7.1. This exception allows the Unit to heat up above COLD SHUTDOWN when the overhead emergency power path is inoperable for greater than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months due to an inoperable Keowee Hydro Unit. The Required Actions detailed below are prerequisites for use of the special inoperability period. With the exception of Lee energizing the standby buses, in the event these Required Actions are not met during the special inoperability period, 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed by Required Action J.3 to restore (continued)

Oconee Units 1, 2, & 3 B 3.7-14 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

ACTIONS J.1 through J.5 (continued) the inoperable component. For example, if the Keowee Hydro Unit has been inoperable for 15 days and one ES power system string (required by TS 3.7.2) is discovered to be inoperable, the ES power system string must be restored to OPERABLE status within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

1. The standby buses are continuously energized by an OPERABLE Lee gas turbine through the 100kV transmission circuit. The 100kV transmission circuit shall be electrically separated from the system grid and all offsite loads. This arrangement provides a high degree of reliability for the emergency power system. In this configuration, the Lee gas turbine is serving as the second onsite emergency power source, however since the 100kV transmission circuit is vulnerable to severe weather a time limit is imposed. Required Action J.1 permits the standby buses to be reenergized by an OPERABLE Lee gas turbine within I hour in the event this source is lost. For example, if one Keowee Unit has been inoperable for 20 days and the Lee gas turbine feeding the 100kV line trips, the 100kV line must be reenergized from an OPERABLE Lee gas turbine within the next hour.

2. Two offsite sources and the underground emergency power path are verified and maintained OPERABLE by complying with TS 3.7.1. This Required Action provides additional assurance that offsite power will be available during the special inoperability period. In addition this Required Action assures that underground emergency power path is available.

3. The overhead emergency power path (excluding the inoperable overhead Keowee Hydro Unit) is verified and maintained OPERABLE by complying with TS 3.7.1. This Required Action assures that the overhead emergency power path is available. Operator action will be required to connect the OPERABLE underground Keowee Hydro Unit to the overhead emergency power path should the underground emergency power path fail.

4. Distribution Systems are verified and maintained OPERABLE by complying with TS 3.7.2. This Required Action increases the probability that power will not be lost to ESF equipment even in the unlikely event of single failures unrelated to the special inoperability period.

5. EPSL is verified and maintained OPERABLE by complying with TSs 3.7.3, 3.7.4, 3.7.5, and 3.7.6. This Required Action increases the probability that EPSL will function as required even in the unlikely event of single failures unrelated to the special inoperability period.

(continued)

Oconee Units 1, 2, & 3 B 3.7-15 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1

BASES (continued)

ACTIONS J.1 through J.5 (continued)

6. DC Sources are verified and maintained OPERABLE by complying with TS 3.7.8. This Required Action increases the probability that the DC Sources will function as required to-support EPSL even in the unlikely event of single failures unrelated to the special inoperability period.

7. Vital Inverters are verified and maintained OPERABLE by complying with TS 3.7.9. This Required Action increases the probability that the vital instrumentation inverters will function as required to support EPSL even in the unlikely event of single failures unrelated to the special inoperability period.

The term verify as used in these Required Actions allows for an administrative check by examining logs or other information to determine if the required equipment is inoperable for maintenance or other reasons. It does not require unique performance of Surveillance Requirements needed to demonstrate operability of the equipment.

Following completion of the prerequisites for the special inoperability period, the underground emergency power path must be demonstrated to be OPERABLE. This demonstration is to assure that the underground emergency power path is not inoperable due to a common cause or due to an undetected failure. When the standby buses are energized by an OPERABLE Lee gas turbine, the likelihood that the OPERABLE emergency power path will be required is decreased, thus testing on a 7 day frequency is adequate. Credit can be taken for the operability of the SK and S breakers per the routine surveillance test (SR 3.7.1.2 and SR 3.7.1.7).

K.1 through K.5 Condition K has been established to allow maintenance and repair of the Keowee Main Step-up transformer which requires longer than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months per Condition C. A "Keowee Hydro Unit" is considered to be all components between ACBs 1, 2, 3, and 4, as well as all components between auxiliary transformer CX and the Keowee Main Step-up transformer. If both Keowee auxiliary transformers (IX and 2X) are inoperable the Keowee Main Step-up transformer is considered to be inoperable, because one of the functions of the Main Step-up transformer is supplying auxiliary loads for the overhead emergency power path. Transformer replacement is rare but would be time extensive.

Other items which manifest as failures are expected to be extremely rare and could possibly be performed during the permitted maintenance periods. A maximum period of 28 days is allowed for an inoperable Keowee Main Step-up transformer. This would allow a reasonable period of time for transformer replacement. The 28 day Completion Time for the Keowee Main Step-up transformer is not counted toward the 45 day Completion Time for each Keowee Hydro Unit. The 3 days from Condition C are added to the 25 day Completion Time in Condition K to get the 28 day time period.

(continued)

Oconee Units 1,2, & 3 B 3.7-16 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

K. I through K.5 (continued)

The Required Actions for the special inoperability period have been modified by a NOTE which provides an exception to TS 3.7.0 when an OPERABLE Lee gas turbine is energizing the standby buses as required by TS 3.7.1. This exception allows the Unit to heat up above COLD SHUTDOWN when the Keowee Main Step-up transformer is inoperable for greater than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The Required Actions detailed below are prerequisites for use of the special inoperability period. With the exception of Lee energizing the standby buses, in the event these Required Actions are not met during the special inoperability period, 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed by Required Action K.3 to restore the inoperable component. For example, if the Keowee Main Step-up transformer has been inoperable for 15 days and one ES power.system string (required by TS 3.7.2) is discovered to be inoperable, the ES power system string must be restored to OPERABLE status within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

1. The standby buses are continuously energized by an OPERABLE Lee gas turbine through the 100kV transmission circuit. The 100kV transmission circuit shall be electrically separated from the system grid and all offsite loads. This arrangement provides a high degree of reliability for the emergency power system. In this configuration, the Lee gas turbine is serving as the second onsite emergency power source, however since the 100kV transmission circuit is vulnerable to severe weather a time limit is imposed. Required Action K. 1 permits the standby buses to be reenergized by an OPERABLE Lee gas turbine within I hour in the event this source is lost. For example, if the Keowee Main Step-up transformer has been inoperable for 20 days and the Lee gas turbine feeding the 100kV line trips, the 100kV line must be reenergized from an OPERABLE Lee gas turbine within the next hour.

2. Two offsite sources and the underground emergency power path are verified and maintained OPERABLE by complying with TS 3.7.1. This Required Action provides additional assurance that offsite power will be available during the special inoperability period. In addition, this Required Action assures that underground emergency power path is available.

3. The overhead Keowee Hydro Unit is verified and maintained OPERABLE by complying with TS 3.7.1. This Required Action assures that the overhead Keowee Hydro Unit is available. Operator action will be required to connect the overhead Keowee Hydro Unit to the OPERABLE underground emergency power path should the underground Keowee Hydro Unit fail.

4. Distribution Systems are verified and maintained OPERABLE by complying with TS 3.7.2. This Required Action increases the probability that power will not be lost to ESF equipment even in the unlikely event of single failures unrelated to the special inoperability period.

(continued)

Oconee Units 1, 2, & 3 B 3.7-17 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

K. I through K.5 (continued)

5. EPSL is verified and maintained OPERABLE by complying with TSs 3.7.3, 3.7.4, 3.7.5, and 3.7.6. This Required Action increases the probability that EPSL will function as required even in the unlikely event of single failures unrelated to the special inoperability period.

6. DC Sources are verified and maintained OPERABLE by complying with TS 3.7.8. This Required Action increases the probability that the DC Sources will function as required to support EPSL even in the unlikely event of single failures unrelated to the special inoperability period.

7. Vital Inverters are verified and maintained OPERABLE by complying with TS 3.7.9. This Required Action increases the probability that the vital instrumentation inverters will function as required to support EPSL even in the unlikely event of single failures unrelated to the special inoperability period.

The term verify as used in these Required Actions allows for an administrative check by examining logs or other information to determine if the required equipment is inoperable for maintenance or other reasons. It does not require unique performance of Surveillance Requirements needed to demonstrate operability of the equipment.

Following completion of the prerequisites for the special inoperability period, the underground emergency power path must be demonstrated to be OPERABLE. This demonstration is to assure that the underground emergency power path is not inoperable due to a common cause or due to an undetected failure. When the standby buses are energized by an OPERABLE Lee gas turbine, the likelihood that the OPERABLE emergency power path will be required is decreased, thus testing on a 7 day frequency is adequate. Credit can be taken for the operability of the SK and S breakers per the routine surveillance test (SR 3.7.1.2 and SR 3.7.1.7).

L. 1 A NOTE has been included to allow separate Condition entry for each inoperable breaker. Thus, Completion Times are tracked separately for the Ni, N2, SLI, and SL2 breakers.

The two trip circuits for each closed N and SL breakers are required to ensure both breakers will open. An N breaker trip circuit encompasses those portions of the breaker control circuits necessary to trip the associated N breaker from the output of the 2 out of 3 logic matrix formed by the auxiliary transformer's undervoltage sensing circuits up to and including an individual trip coil for the associated N breaker. The undervoltage sensing channels for the auxiliary transformer are addressed in Technical Specification 3.7.4, "Emergency Power Switching Logic (EPSL) Voltage Sensing Circuits." An SL breaker trip circuit encompasses those portions of the breaker control circuits necessary to trip the associated SL breaker from the output of both 2 out of 3 logic matrices formed (continued)

Oconee Units 1. 2, & 3 B 3.7-18 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

L.1 (continued) by each standby bus's undervoltage sensing circuits up to and including an individual trip coil for the associated SL breaker. The undervoltage sensing channels for the CT-5 transformer are addressed in Technical Specification 3.7.4, "Emergency Power Switching Logic (EPSL) Voltage Sensing Circuits." With one trip circuit inoperable, a single failure could prevent an N or SL breaker from opening. This could prevent the transfer to other available sources. Therefore, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed to repair the trip circuit or open the breaker. The completion time is based on engineering judgment taking into consideration the time required to complete the required action and the availability of the remaining trip circuit.

M.1 and M.2 If the Required Actions and associated Completion Times cannot be met, the unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in the following 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . These times allow for a controlled shutdown of one or all three Units without

-placing undue stress on plant operators or plant systems.

SURVEILLANCE SR 3.7.1.1 REQUIREMENTS SRs 3.7.8.1, 3.7.8.3, 3.7.8.4, and 3.7.8.5 are performed to ensure Keowee battery OPERABILITY.

SR 3.7.1.2 This surveillance is modified by two NOTES. NOTE I allows the surveillance to be performed without energizing the standby buses from Keowee when the standby buses are energized by an OPERABLE Lee gas turbine. An OPERABLE Lee gas turbine and Keowee Hydro Unit cannot energize the standby buses simultaneously. NOTE 2 indicates that the surveillance is not required to be met for the Keowee Hydro Unit which is associated with the overhead emergency power path when the overhead electrical disconnects for the Keowee Hydro Unit associated with the underground emergency power path are open. When the overhead electrical disconnects are open, the Keowee Hydro Units are not vulnerable to a zone overlap fault which would result in the overhead Keowee Hydro Unit being automatically transferred to the underground emergency power path. Thus, the overhead Keowee Hydro Unit does not need to be verified OPERABLE to the underground emergency power path.

This surveillance is to verify the availability of underground emergency power path.

Utilization of the auto-start or emergency start sequence assures the control function operability by verifying proper speed control and voltage. Power path verification is included to demonstrate breaker operability from each of the Keowee Units onto the Standby Buses. This is accomplished by exercising the Keowee Feeder Breakers (SK) to energize both Standby Buses. The Monthly frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability (continued)

Oconee Units 1, 2, & 3 B 3.7-19 Amendment 232 Unit I Amendment 232 Unit 2 Amendment __1 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

SURVEILLANCE SR 3.7.1.2 (continued)

REQUIREMENTS verification without excessive equipment cycling for testing. For cases where a Keowee unit can only be connected to one emergency power path, this monthly surveillance will only be performed on the one emergency power path.

SR 3.7.1.3 This surveillance is modified by a NOTE which indicates that the surveillance is only required to be met for the Keowee Hydro Unit associated with the overhead emergency power path. The underground Keowee Hydro Unit cannot automatically transfer to the overhead emergency power path. Thus, the underground Keowee Hydro Unit does not need to be verified OPERABLE to the overhead emergency power path.

This surveillance is to verify the availability of overhead emergency power path.

Utilization of the auto-start or emergency start sequence assures the control function operability by verifying proper speed control and voltage. The ability to supply the Overhead path is satisfied by demonstrating the ability to synchronize (automatically or manually) each Keowee Unit with the Yellow bus in the 230 kV switchyard. The remaining path components are considered OPERABLE by the existence of adequate power to each of the Oconee Unit Startup Transformers. The Monthly frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability verification without excessive equipment cycling for testing. For cases where a Keowee unit can only be connected to one emergency power path, this monthly surveillance will only be performed on the one emergency power path.

SR 3.7.1.4 This surveillance is modified by two NOTES. NOTE 1 indicates SR 3.7.1.2 can be performed instead of SR 3.7.1.4. This NOTE prevents the performance of redundant testing of the underground Keowee Hydro Unit. NOTE 2 allows the surveillance to be performed without energizing the standby buses when the standby buses are energized by an OPERABLE Lee gas turbine. An OPERABLE Lee gas turbine and Keowee Hydro Unit cannot energize the standby buses simultaneously.

This surveillance is to verify the availability of underground emergency power path.

Utilization of the auto-start or emergency start sequence assures the control function operability by verifying proper speed control and voltage. Power path verification is included to demonstrate breaker operability from each of the Keowee Units onto the Standby Buses. This is accomplished by exercising the Keowee Feeder Breakers (SK) to energize both Standby Buses. The Monthly frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability verification without excessive equipment cycling for testing.

(continued)

Oconee Units 1, 2, & 3 B 3.7-20 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

SURVEILLANCE SR 3.7.1.5 REQUIREMENTS This surveillance is modified by a NOTE which indicates SR 3.7.1.3 can be performed instead of SR 3.7.1.5. This NOTE prevents the performance of redundant testing of the overhead Keowee Hydro Unit.

This surveillance is to verify the availability of overhead emergency power path.

Utilization of the auto-start or emergency start sequence assures the control function operability by verifying proper speed control and voltage. The ability to supply the Overhead path is satisfied by demonstrating the ability to synchronize (automatically or manually) each Keowee Unit with the Yellow bus in the 230 kV switchyard. The remaining path components are considered OPERABLE by the existence of adequate power to each of the Oconee Unit Startup Transformers. The Monthly frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability verification without excessive equipment cycling for testing.

SR 3.7.1.6 This surveillance is modified by two NOTES. NOTE 1 indicates that the surveillance is only required to be met when the associated breaker is closed. The trip function is not necessary when the breaker is already open. NOTE 2 to this surveillance states that the surveillance is not required to be performed for the SL breakers when the overhead emergency power path is inoperable > 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . When the overhead emergency power path is inoperable for> 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , the SL breakers must remain closed to energize the standby buses from an OPERABLE Lee gas turbine.

This surveillance is to verify operability of the trip functions of the SL and N breakers.

Neither of these breakers have any automatic close functions; therefore, only the trip coils require verification.. Cycling of each breaker demonstrates functional operability and the coil monitor circuits verify coil integrity. The Monthly frequency is based on operating experience.

SR 3.7.1.7 This surveillance is modified by a NOTE which indicates that the surveillance is not required to be performed for the S breakers when the overhead emergency power path is inoperable> 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . When the overhead emergency power path is inoperable for> 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , the S breakers cannot be cycled, because cycling the S breakers connects the standby buses which are energized from an OPERABLE Lee gas turbine with the main feeder buses which are energized from another source.

Infrequently used source breakers need to be cycled to ensure availability. The Standby breakers are to be cycled one breaker on one Unit at a time to prevent inadvertent interconnection of two Units through the Standby Bus Breakers. Cycling the Startup breakers verifies operability of the breakers and associated interlock circuitry between (continued)

Oconee Units 1, 2, & 3 B 3.7-21 Amendment 232 Unit .1 Amendment 232 Unit 2 Amendment 231 Unit 3

. BASES (continued)

AC Sources - Operating B 3.7.1 SURVEILLANCE SR 3.7.1.7 (continued)

REQUIREMENTS the Normal and Startup breakers. This circuitry provides an automatic, smooth, and safe transfer of Auxiliaries in both directions between sources. The Monthly frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability verification without excessive equipment cycling for testing.

SR 3.7.1.8 The Keowee tie breakers to the Underground Path, ACB3 and ACB4, are interlocked to prevent cross-connection of the Keowee Generators. The safety analysis utilizes two independent power paths for accommodating single failures in applicable DBAs.

Connection of both generators to the Underground path would compromise the redundancy of the emergency power paths. Test logic is installed to verify a circuit to the close coil on one Underground ACB does not exist with the other Underground ACB closed. Interlocks preventing the Keowee Unit which is aligned to the underground path from automatically closing to the overhead path are also verified OPERABLE. The annual frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability verification without excessive equipment cycling for testing.

SR 3.7.1.9 This surveillance is modified by a NOTE which indicates that the surveillance is only required to be met when a Lee gas turbine is energizing the standby buses. A Lee gas turbine is not required to be OPERABLE when it is not energizing the standby buses.

The Lee Gas Turbines can be used as a reliable altemate "onsite" power source when connected through a 100kV line which is not connected to any other load or system.

Since the use of this source is not frequent, the integrity and validity of the path must be verified by actually powering the Standby Buses with the Lee Gas Turbines. More frequent cycling of the Standby breakers is already performed per SR 3.7.1.7. The annual frequency for this surveillance is reasonable based on operating experience.

SR 3.7.1.10 This surveillance is modified by a NOTE which indicates that the surveillance is only required to be met when a Lee gas turbine is energizing the standby buses. A Lee gas turbine is not required to be OPERABLE when it is not energizing the standby buses.

The Design Bases response for the Lee Gas Turbines is to supply power to the Oconee Site equal to one Unit's maximum safeguards and two Unit's HOT SHUTDOWN loads.

The Oconee Site cannot provide equivalent loads without establishing an unanalyzed electrical system alignment. Therefore, the load capability is established by requiring connection to the system grid and loading to the accident equivalent load. The annual frequency for this surveillance is reasonable based on operating experience.

(continued)

Oconee Units 1, 2, & 3 B 3.7-22 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1

BASES (continued)

SURVEILLANCE SR 3.7.1.11 REQUIREMENTS This surveillance verifies the Keowee Units' response time to an Emergency Start signal to ensure ES equipment will have adequate power for Design Accident mitigation. Two locations exist for Control Room manual initiation of Keowee Emergency Start logic.

Oconee Units 1 & 2 or Unit 3 Control Room. Each Unit has individual logic which actuates the associated Emergency Start relays. This provides the ability to verify operability of each Control Room Logic independent of each Oconee Unit. A Refueling frequency surveillance, SR 3.7.1.14 (EPSL functional test), verifies the ES input. FSAR Section 6.3.3.3 establishes the 23 second time requirement for each Keowee Unit to obtain full speed and voltage. Since the only available loads of adequate magnitude for simulating a DBA is the Grid, subsequent loading on the Grid is required to verify the Unit's ability to assume rapid loading under accident conditions. Ideally, sequential block loads would be applied to fully test this function, but such loads are not available.

This explains the requirement to load the Keowee Units at the maximum practical rate to the equivalent of a LOCA/LOOP situation. Current value for the maximum accident loads may be found in FSAR Table 8-1. The Annual frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability verification without excessive equipment cycling for testing.

SR 3.7.1.12 This surveillance is modified by a NOTE. The NOTE indicates that the surveillance is not required to be met when the overhead electrical disconnects for the Keowee Hydro Unit associated with the underground emergency power path are open. When the overhead electrical disconnects are open, the Keowee Hydro Units are not vulnerable to a zone overlap fault which would result in the overhead Keowee Hydro Unit being automatically transferred to the underground emergency power path.

The Keowee Underground ACBs have a control feature which will automatically close the Keowee Unit, that is pre-selected to the Overhead Path, into the Underground Path upon an electrical fault in the zone overlap region of the protective relaying. This circuitry prevents an electrical fault in the zone overlap region of the protective relaying from locking out both emergency power paths during dual Keowee Unit grid generation.

In order to ensure this circuitry is OPERABLE, an electrical fault is simulated in the zone overlap region and the associated Underground ACBs are verified to operate correctly. This surveillance will be performed on an annual frequency.

(continued)

Oconee Units 1, 2, & 3 B 3.7-23 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

BAS S (cntined)AC Sources - Operating B 3.7.1 BASES (continued)

SURVEILLANCE SR 3.7.1.13 REQUIREMENTS This surveillance is modified by a NOTE which indicates that the surveillance is only required to be met when a Lee gas turbine is energizing the standby buses. A Lee gas turbine is not required to be OPERABLE when it is not energizing the standby buses.

The Design Bases response for the Lee Gas Turbines is to supply power to the Oconee site. Therefore, the capability of the Lee Gas Turbines to supply the Oconee main feeder buses is demonstrated by loading a Lee Gas Turbine on the isolated 100kV line with the equivalent of a single Unit's maximum safeguards loads (4.8MVA) within one hour. An 18 month frequency for this surveillance is reasonable based on operating experience and the one hour time response required of the source.

SR 3.7.1.14 This surveillance performs functional verification for the source and Main Feeder Bus voltage sensing, Keowee Emergency start, Loadshed and Transfer-to-Standby, and Retransfer-to-Startup logic of the EPSL System. The method is designed to provide actual power failures remote from the Main Feeder Buses so that the logic may be monitored. For SR purposes, a "failed" source is defined as the complete loss of voltage.

The ramp/rate/time responses for the voltage relays are verified independently as a prerequisite to this SR. Circuits actuated by the source undervoltage relays are verified per SR 3.7.4.1. To eliminate the human or computer error in timing events, critical time setpoints for Load shed, Transfer-to-Standby, Retransfer-to-Startup, and reactor coolant pump trip relays are verified independently during the refueling outage. This test verifies the integrated response of the circuits. Key circuits for verification include the Engineered Safeguards contacts to the Keowee Emergency Start, Loadshed and Transfer/Retransfer relays, and close permissive for Keowee Feeder Breakers (SK).

Excessive cycling of equipment may be prevented by using a single action input, verification of the required end result by alarms or visual inspection, subsequent reset of the initiating logic, and then insertion of an alternate input for verification of the required circuits. An 18 month frequency for this Surveillance was determined to be adequate based on operating experience to provide reliability verification without excessive equipment cycling for testing. This surveillance will be performed during the refueling outage for each Oconee unit.

(continued)

Oconee Units 1, 2, & 3 B 3.7-24 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 ASES (continued)

SURVEILLANCE SR 3.7.1.15 REQUIREMENTS This surveillance is modified by a NOTE which indicates that the surveillance is only required to be met during periods of commercial power generation using the Keowee Hydro Units. The logic which aligns the Keowee Hydro Units following a load rejection from commercial power generation is not required to be operable when the Keowee Hydro Units are not providing commercial power.

In order to ensure that the Keowee Hydro units are operable during periods of commercial power generation, the protection circuitry will be tested on an 18 month frequency. This surveillance will ensure that the adverse effects of overspeed following a load rejection will be precluded and the appropriate emergency power paths will be aligned. In addition, the speed sensing governor failure logic will be verified during this surveillance. The Keowee Watt/VAR meter, frequency relays, and governor magnetic speed switch will be calibrated prior to the performance of this surveillance. This surveillance can be performed with one or both Keowee units operating at any load below the maximum power level as defined by the Keowee operating restrictions.

SR 3.7.1.16 This surveillance is modified by a NOTE which indicates that the surveillance is only required to be met during periods of commercial power generation using the Keowee Hydro Units. The response of the Keowee Hydro Units following a load rejection from commercial power generation is not required to be bounded by the design criteria, which were used to develop the Keowee operating restrictions, when the Keowee Hydro Units are not providing commercial power.

A maximum power dual unit load rejection will be performed on an 18 month frequency.

This surveillance will verify that the Keowee Hydro units response to a load rejection is bounded by the design criteria used to develop the Keowee operating restrictions. The design criteria are defined in the calculation that determines the Keowee operating restrictions. A power level for the dual unit load rejection will be defined based on the operating conditions for the day of the test. In addition, a revision of the operating restrictions for simultaneous operation of both Keowee units will require that a maximum power dual unit load rejection test be performed prior to implementing the revision. A revision of the operating restrictions for a single Keowee unit will require only a maximum power single unit load rejection as defined by the conditions for the day of the test. However, if a load rejection test is performed to support a revision to the operating restrictions, then no additional load rejection test will be required until the next surveillance. The Keowee Watt/VAR meter and frequency relays will be calibrated prior to the performance of this surveillance.

(continued)

Oconee Units 1, 2, & 3 B 3.7-25 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 211 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

SURVEILLANCE SR 3.7.1.17 REQUIREMENTS This surveillance is modified by two NOTES. NOTE 1 indicates that the surveillance is only required to be met vyYen the associated breaker is closed. The trip function is not necessary when the breaker is already open. NOTE 2 to this surveillance states that the surveillance is not required to be performed for the SL breakers when the overhead emergency power path is inoperable 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . When the overhead emergency power path is inoperable for> 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , the SL breakers must remain closed to energize the standby buses from an OPERABLE Lee gas turbine.

This surveillance verifies operability of the trip functions of the SL and N breakers. This surveillance verifies that each trip circuit of each breaker independently opens each breaker. Neither of these breakers have any automatic close functions; therefore, only the trip circuits require verification. An 18 month frequency is based on engineering judgement and provides reasonable assurance that the SL and N breakers will trip when required.

SR 3.7.1.18 This surveillance verifies proper operation of the 230 kV switchyard circuit breakers upon an actual or simulated actuation of the Switchyard Isolation circuitry. This test causes an actual switchyard isolation (by actuation of degraded grid voltage protection) and alignment of the Keowee Hydro Units to the overhead and underground emergency power paths. An 18 month frequency minimizes the impact to Keowee and the operating Units which are connected to the 230 kV switchyard. The effect of this surveillance is not significant because the generator red bus tie breakers and feeders from the Oconee 230 kV switchyard red bus to the system grid remain closed. Either Switchyard Isolation Channel causes full system realignment, which involves a complete switchyard realignment. To avoid excessive switchyard circuit breaker cycling, realignment and Keowee Hydro Unit emergency start functions, this surveillance need be performed for only one Switchyard Isolation Channel each surveillance interval. This is acceptable since operability of the overhead emergency power path requires only one channel of the Switchyard Isolation circuitry to be capable of isolating the switchyard. Functional verification of the Switchyard Isolation Channel logic is addressed in Technical Specification 3.7.6, "Emergency Power Switching Logic (EPSL) Degraded Grid Voltage Protection."

This surveillance is modified by a NOTE. This NOTE states that the redundant breaker trip coils will be verified on a STAGGERED TEST BASIS. This can be accomplished by alternating the switchyard isolation channels which are actuated during each test.

Verifying the trip coils on a STAGGERED TEST BASIS precludes unnecessary breaker operation and minimizes the impact to Keowee and the operating Units which are connected to the 230 kV switchyard.

(continued)

Oconee Units 1, 2, & 3 B 3.7-26 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

AC Sources - Operating B 3.7.1 BASES (continued)

REFERENCES 1. 10 CFR 50.36.

2. 4160V Auxiliary Power System DBD, OSS-0254.00-00-2000.

3. 230kV Switchyard Power System DBD, OSS-0254.00-00-2004.

4. Keowee Emergency Power System DBD, OSS-0254.00-00-2005.

5. Oconee FSAR Section 3.1.39, Criterion 39 Oconee Units 1, 2, & 3 B 3.7-27 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 1 Unit 3

Distribution Systems - Operating B 3.7.2 B3.7 ELECTRICAL POWER SYSTEMS B 3.7.2 Distribution Systems - Operating BASES BACKGROUND The Distribution Systems are comprised of two main feeder buses, three Engineered Safeguards (ES) Power System-strings, four 125VDC Vital I&C Power panelboards, six 230kV switchyard DC Power panelboards, and four 120VAC Vital Instrumentation Power panelboards. This system, which supplies the electrical power required to operate unit equipment during normal plant operation, is designed to provide power to the required Engineered safety features (ESF) loads or safe shutdown loads of each unit such that no single failure can disable enough loads to jeopardize plant safety.

Only one main feeder bus and two ES power system strings are needed to provide power to the minimum required loads. In accordance with proposed AEC general design criterion 39, the design of the AC distribution system provides independence and redundancy to ensure an available source of power to the ESF systems (FSAR 3.1.39).

The system is arranged such that each ES power system string can receive power from either of the two main feeder buses. Each main feeder bus which is capable of supplying the entire unit power needs, can receive power from the unit normal auxiliary transformer, startup transformer and one of the standby buses.

The 125VDC Vital Instrumentation and Control (I&C) System consists of a distribution system as described below. It provides control power for the Emergency Power System.

It also provides both motive and control power to selected safety-related and non-safety equipment. It is designed to have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure.

Four separate 125VDC Vital I&C Power panelboards (DIA, DIB, DIC, DID), are provided for each unit. Each panelboard receives its DC power through an auctioneering network of two isolating diode assemblies. One assembly is supplied from the unit's 125 volt distribution system, and the other assembly is supplied from another unit's (the backup unit) 125VDC Vital Distribution System. The diode assemblies permit the two distribution systems to supply current to the Vital I&C DC Power panelboard connected to the output of the diode assemblies, and block the flow of current from one DC distribution system to the other.

In order to provide all safety functions required during an accident, power must be provided from any three of the four Vital I&C DC Power panelboards. During normal operation, the auctioneering network described above provides multiple redundancy for assuring that power from the 125VDC Vital I&C Sources would be provided to the Vital I&C DC Power panelboards. Therefore, power from any three of the four Vital I&C DC Sources for a particular unit (two for the unit considered, and two from the backup unit) continues to provide redundancy of power sources for safety functions performed by the Vital DC I&C Power panelboards.

The ungrounded DC system has detectors and alarms to indicate when there is a ground existing on any leg of the system. A ground on one leg of the DC system will not cause any equipment to malfunction. In order to find and correct a DC ground on the 125VDC Vital I&C System, each unit's DC system must be separated from the other two units.

(continued)

Oconee Units 1, 2, & 3 B 3.7-28 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

Distribution Systems - Operating B 3.7.2 BASES (continued)

BACKGROUND With the backup function disabled, the unit would be in a degraded mode, but would in (continued) fact have all of its own DC system available if needed. Each unit's batteries (either CA or CB) is capable of carrying all the 125VDC instrumentation and control loads on that unit.

Unit 1 panelboards IDIC and IDID provide primary and backup power for SK and SL breakers control power, standby bus protective relaying control power, standby breakers control power for all three Units, and retransfer-to-startup source switching circuits for all three Oconee Unit's Emergency Power Switching Logic Systems. All other safety related functions supported by the Vital 125VDC Power panelboard are unit specific.

The 230kV Switchyard (SY) 125VDC System consists of a distribution system as described below. It provides primary and backup DC power for protective relaying and actuation circuits associated with the 230kV SY, as well as DC control power for 230kV SY power circuit breaker (PCB) operation. It is designed to have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure.

Safety functions provided by the 230kV SY 125VDC System include:

a) connection of on-site power from Keowee to Oconee via the emergency onsite overhead power path, and b) isolation of Oconee (including Keowee) from degraded grid voltage through action of the Degraded Grid Protection System (DGPS).

With the exception of the functions of the DGPS, all functions of the 230kV Switchyard DC Distribution System can be considered redundant to those associated with the emergency onsite underground power path.

The output of 230kV SY 125VDC Sources SY-1 and SY-2 are connected to Distribution Centers SY-DC-1 and SY-DC-2, respectively. The buses are metal-clad two conductor assemblies. A bus tie with normally open breakers is provided between the distribution centers to "backup" a battery when it is removed for servicing. SY-DC-1 supplies DC Panelboards DYA, DYB, DYC, and DYD; SY-DC-2 supplies DC Panelboards DYE, DYF, DYG, and DYH. DC Panelboards DYD and DYH provide power for non-safety functions, and are not directly subject to the Technical Specifications. Distribution Centers SY-DC-1 and SY-DC-2 with their associated safety-related DC panelboards and interconnecting wiring and breakers comprise the 230kV SY DC Distribution System.

The two distribution centers are redundant, each providing power to all components necessary for performing the safety functions of the 230kV SY DC System. DC Panelboard DYA is redundant to DYE; DYB is redundant to DYF, and DYC is redundant to DYG. Thus, the failure of any single component in the 230kV SY DC Distribution System, or in their associated 125VDC Sources, will not prevent any safety function from being performed. The redundant panelboards supply power to separate channels of the Degraded Grid Protection System (DGPS) circuits, separate channels of other protective relaying circuits, and separate feeds for each 230kV SY PCB's closing and tripping control. Separate dual trip coils are provided for each PCB. Isolating diodes are provided for redundant power feeds to each PCB's common closing coil circuit.

(continued)

Oconee Units 1, 2, & 3 B 3.7-29 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

Distribution Systems - Operating B 3.7.2

BASES (continued)

BACKGROUND The ungrounded DC system has detectors and alarms to indicate when there is a ground (continued) existing on any leg of the system. A single ground will not cause any malfunction or prevent operation of any safety function.

The AC Vital Distribution System is comprised of four redundant 120VAC vital instrument power panelboards for each unit which provide power to associated vital instrumentation and control loads under all operating conditions. Each panelboard is powered separately from a static inverter connected to one of the four 125VDC instrumentation and control panelboards. In order to accommodate maintenance on the inverters and supply backup power, a tie with breakers is provided to each of the 120VAC vital panelboards from the alternate 120VAC regulated bus.

Each of the four redundant channels of Nuclear Instrumentation and Reactor Protective System (RPS) equipment on each unit is powered from a separate 120VAC vital panelboard. Separate 120VAC panelboards also supply each of the three redundant Engineered Safeguards (ES) system analog channels and each of the two redundant ES digital channels for each unit.

APPLICABLE The initial conditions of design basis transient and accident analysis in the FSAR SAFETY Chapter 6, (Engineered Safeguard), and 15, (Accident Analyses), assume all ESF ANALYSES systems are OPERABLE. The Distribution Systems are designed to provide sufficient capacity, capability, redundancy and reliability to ensure the availability of necessary power to ESF systems so that the fuel, reactor coolant system and containment design limits are not exceeded.

In general, the safety analysis considered power to be available to Engineered Safeguards equipment following event initiation and is based on maintaining at least two of the ES Power System strings OPERABLE during accident conditions.

For an accident concurrent with a loss of all offsite power assuming a worst case single failure, the 125VDC Vital I&C System provides power to components which function to maintain OPERABLE:

a. at least one of the onsite (or offsite power sources, if available),

b. two ES power system strings,

c. at least three inverters for the Vital AC Distribution System, described in TS 3.7.9.

For an ES actuation concurrent with a loss or degradation of offsite AC power, assuming a worst case single failure, the 230kV DC SY Distribution System provides power to components and protective systems which function to:

a. maintain OPERABLE at least one of the onsite power sources, and

b. separate Oconee and the onsite power sources from the electrical system be lost or degraded.

grid, should grid voltage (continued)

Oconee Units 1, 2, & 3 B 3.7-30 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

Distribution Systems - Operating B 3.7.2 BASES (continued)

APPLICABLE Distribution Systems - Operating is a system that is part of the primary success path and SAFETY functions to mitigate a Design Basis Accident (DBA) or transient that presents a ANALYSES challenge to the integrity of a fission product barrier. As such, Distribution Systems (continued) Operating satisfies the requirements of selection criterion 3 of 10 CFR 50.36 (Ref. 1).

TS Distribution Systems ensure the availability of power to the required loads to shutdown the reactor and maintain it in a safe shutdown condition after an anticipated operational occurrence or a postulated DBA.

Main Feeder Bus A main feeder bus is considered OPERABLE if it meets all of the following conditions:

1. The bus is energized;

2. It is receiving power or capable of automatically receiving power from its associated E breaker or S breaker;

3. Connected to at least two ES power system switchgears (TC, TD & TE).

ES Power System String The three ES Power System Strings are defined as follows:

IA) ES Switchgear TC IB) ES Switchgear TD IC) ES Switchgear TE 2A) Load Center X8 2B) Load Center X9 2C) Load Center X10 3A) 600V MCC XSI and 3B) 600V MCC XS2 3C) 600V MCC XS3 1,2, 3XSF 4A) 208V MCC XSI and 4B) 208V MCC XS2 4C) 208V MCC XS3 1, 2, 3XSF Each string is considered OPERABLE if it is energized by at least one main feeder bus.

When MCC 1, 2, or 3XSF is powered from load center OXSF, these MCCs would not be available during a DBA. Therefore, these MCCs shall be considered inoperable if it is powered from load center OXSF during non-SSF event periods.

125VDC I&C Power panelboards For unrestricted operation, the four 125VDC I&C Panelboards (DIA, DIB, DIC, & DID) shall be OPERABLE. A panelboard is considered OPERABLE when it is energized from an OPERABLE source.

Because power from any three of the four panelboards DIA, DIB, DIC, or DID would support all safety functions associated with the panelboards, these requirements ensure that the supported safety functions are not vulnerable to a single failure.

(continued)

Oconee Units 1, 2, & 3 B 3.7-31 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

. BASES (continued)

TS Distribution Systems - Operating Panelboards IDIC and IDID affect all three Units since these panelboards provide B 3.7.2 (continued) primary and backup power for SK and SL breakers control power, standby bus protective relaying control power, standby breaker control power for all three Units and retransfer to startup source for all three Units.

230kV Switchyard DC Power panelboards For unrestricted operation, the 230kV SY DC Power panelboards (DYA, DYB, DYC, DYE, DYF, DYG) shall be OPERABLE. For the 230kV SY DC Power panelboards to be considered OPERABLE, they must be energized from an OPERABLE source.

120VAC Vital Instrumentation Power panelboards All four 120VAC vital instrumentation power panelboards (KVIA, KVIB, KVIC, and KVID) are required to be OPERABLE. Implicit in this is that all breakers and connecting hardware that are necessary for the circuit to perform its intended function are OPERABLE.

APPLICABLITY The Distribution Systems for ESF systems are required to be OPERABLE above COLD SHUTDOWN to ensure that:

1. Acceptable fuel design limit and reactor coolant pressure boundary limits are not exceeded as a result of anticipated operational occurrences or abnormal transients, and

2. Adequate core cooling is provided, and containment integrity and other vital functions are maintained in the event of a postulated DBA.

The 125VDC Vital I&C Power panelboards are required to be OPERABLE above COLD SHUTDOWN to support functions of the Engineered Safeguards System, the Reactor Protective System, the Emergency Power Switching Logic, and certain other safety functions.

The 230kV SY DC Power panelboards are required to be OPERABLE above COLD SHUTDOWN to ensure continued operability of the overhead power path, and to provide protection of the safety related portion of the 230kV SY from potential degradation of voltage on the electrical power grid.

During an accident, with or without loss of offsite power, unless an extended degradation of voltage from offsite power occurred, all requirements would be met without operation the 230kV SY DC Sources and Distribution System. With extended partial degradation of the offsite power voltage, operation of the DGPS, which is supported by the 230kV SY 125VDC System, would be required.

The 120VAC Vital Instrumentation Power panelboards are required to be OPERABLE above COLD SHUTDOWN to assure that power is supplied to the.ES and RPS systems.

ACTIONS The required actions have been established based on the level of degradation of the distribution systems.

(continued)

Oconee Units 1,2, & 3 B 3.7-32 Amendment 232_. Unit 1 Amendment _ZU. Unit 2 Amendment 231 Unit 3

Distribution Systems - Operating B 3.7.2 BASES (continued)

ACTIONS A.1 (continued)

With one of the main feeder buses inoperable, the remaining main feeder bus is fully capable of supporting the safety functions necessary to shutdown the unit and maintain it in a safe shutdown condition, assuming no single failure. However the overall reliability is reduced because a single failure in the remaining main feeder bus could result in the minimum required ESF functions not being supported. Therefore the inoperable main feeder bus must be restored to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The completion time is based on engineering judgment taking into consideration the time required to reasonably complete the required action and the availability of the remaining main feeder bus.

B.1 With one of the ES power system strings inoperable, the remaining two ES power system strings are capable of supporting the minimum required safety function necessary to shutdown the unit and maintain it in a safe shutdown condition, assuming no single failure. However, the overall reliability is reduced because a single failure in the remaining ES power system strings could result in the minimum ESF functions not being supported. Therefore, the inoperable string must be restored to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The completion time is based on engineering judgment taking into consideration the time required to reasonably complete the required action and availability of the two remaining ES power system strings.

With one 125VDC Vital I&C Power panelboard inoperable, the three remaining panelboards will continue to provide power for all safety functions supported by Vital I&C DC. Failure of one of the three remaining panelboards could result in failure to support required ES functions or Unit trip.

An inoperable panelboard shall be restored to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . This conservative requirement assures continued redundancy in the 125VDC Vital I&C Distribution System, and recognizes the importance of the multiple functions supported by the panelboards.

D.1 If any required 230kV SY DC panelboard or combination of panelboards are inoperable, the inoperable panelboard(s) shall be restored to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

This requirement assures continued redundancy in the distribution system. Loss of a redundant panelboard could result in failure of the overhead emergency power path. In addition, in the event of grid degradation, the station and onsite emergency power sources could fail to separate from the grid.

The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months completion time is based on engineering judgment taking into consideration the time to complete the required action, the redundancy available in the 230kV SY DC system, the redundancy available in the emergency power paths, and the infrequency of an actual grid system degradation.

(continued)

Oconee Units 1, 2, & 3 B 3.7-33 Amendment 232 Unit I Amendment 232 Unit 2 Amendment -1 Unit 3

. BASES (continued)

ACTIONS D.I (continued)

Distribution Systems - Operating B 3.7.2 (continued)

A NOTE is included to clarify that a separate condition entry is allowed for each 230kV switchyard DC Power panelboard. If a loss of safety function occurs due to inoperability of redundant panelboards, Condition I will address the Required Action.

E. 1 With IDIC inoperable or IDID inoperable, single failure of the remaining panelboard would result in failure of control power for the S, SK, and SL breakers, standby bus protective relaying, and retransfer to startup logic for all three Units. Therefore, within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after such a condition arises, the inoperable panelboard shall be restored. The completion time is based on engineering judgment taking into consideration the time to complete the required action and the redundancy available in the Vital I&C DC System.

A NOTE has been included to clarify that Condition E is not applicable to Unit 1.

Condition C applies to Unit 1.

F. 1 If panelboard KVIA or KVIB becomes inoperable, for reasons other than inverter inoperability, a period of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed to return the panelboard to OPERABLE status. The digital ES channels are powered from KVIA and KVIB, and cannot actuate without power. The 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months completion time is based on engineering judgment taking into consideration the time to complete the required action, the operability of redundant panelboards, and the low likelihood of an event requiring ES actuation.

G.1 If panelboard KVIC or KVID is inoperable for reasons other than inverter inoperability, it must be returned to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months completion time is based on engineering judgment taking into consideration the time to complete the required action, the operability of redundant panelboards, and the low likelihood of an event requiring loads powered by KVIC or KVID.

H.1 and H.2 If the required actions and associated completion times cannot be met, the unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in the following 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

These times allow for a controlled shutdown of the unit without placing undue stress on plant operators or plant systems.

1.1 The inoperability of two or more main feeder buses, ES Power System Strings, 125VDC Vital I&C Power panelboards, or 120VAC Vital Instrumentation Power panelboards could result in a loss of safety function. In addition, the inoperability of two redundant 230kV switchyard DC Power panelboards could result in the loss of safety function.

Therefore, the provisions of TS 3.0 apply.

(continued)

-Oconee Units 1, 2, & 3 B 3.7-34 Amendment 232 Unit I Amendment 232 Unit 2 Amendment .23t Unit 3

Distribution Systems - Operating B 3.7.2 BASES (continued)

SURVEILLANCE SR 3.7.2.1 REQUIREMENTS This surveillance verifies that the main feeder buses are functioning properly, with the required circuit breakers closed and the buses energized. The 7 day frequency takes into account the redundant capability of the main feeder buses and other indications available in the control room that will alert the operator to system malfunctions.

SR 3.7.2.2 This surveillance verifies that the required ES Power System Strings, 125 VDC Vital I&C Power panelboards, 230 kV switchyard DC Power panelboards, and 120 VAC Vital Instrumentation Power panelboards are functioning properly, with the required circuit breakers closed and the buses energized. The 7 day frequency takes into account the redundant capability of the required ES Power System Strings, 125 VDC Vital I&C Power panelboards, 230 kV switchyard DC Power panelboards, and 120 VAC Vital Instrumentation Power panelboards and other indications available in the control room that will alert the operator to system malfunctions.

REFERENCES 1. 10 CFR 50.36.

2. 4160V Auxiliary Power System DBD,OSS-0254.00-00-2000.

3. 600V Power System DBD,OSS-0254.00-00-2008.

Oconee Units 1, 2, & 3 B 3.7-35 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Automatic Transfer Functions B 3.7.3 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.3 Emergency Power Switching Logic (EPSL) Automatic Transfer Functions BASES BACKGROUND The transfer circuits of the Emergency Power Switching Logic (EPSL) are designed with sufficient redundancy to assure that power is supplied to the unit Main Feeder Buses (MFBs) and, hence, to the unit's essential loads, under accident conditions. The logic system monitors the normal and emergency power sources and, upon loss of the normal power source (the unit auxiliary transformer), the logic will seek an alternate source of power. The EPSL Automatic Transfer functions consist of the Load Shed and Transfer to Standby Circuitry and the Retransfer to Startup logic.

The Load Shed and Transfer to Standby Circuits are designed to energize the MFBs from the Standby Buses powered from either Keowee or Lee. This would occur when voltage is lost or is insufficient from the Normal and Startup sources. The Load Shed signal is generated to separate nonessential breakers from the MFBs to ensure the CT-4 or CT-5 transformers supplying the Standby Buses are not overloaded.

The Retransfer to Startup logic provides the emergency power switching logic the capability to retransfer essential loads from the Standby Bus to the startup source, if available, should power to the Standby Bus be lost for more than 5 seconds.

APPLICABLE The Safety Analysis for Transfer functions of EPSL is contained in Chapter 8 and SAFETY 15 of the FSAR. The initial conditions of the analysis assume all the circuits of ANALYSES EPSL are functional.

The most limiting design basis accident (DBA) for the EPSL transfer functions is a LOCA with a simultaneous loss of offsite power (LOOP). The LOOP is considered to occur coincident with engineering safeguards (ES) actuation. In this scenario, the Load Shed and Transfer to Standby function is expected to reenergize the affected unit's MFBs from the Standby Buses which are expected to be powered from Keowee or Lee. The Load Shed timers and Transfer to Standby timers are set such that, if no power is available from the startup source for 11 seconds, the startup source breakers are prohibited from closing and the standby bus to MFB breakers receive a permissive to close. Power should be available to the MFBs within 23 seconds with the Keowee start and accelerate time being the most limiting parameter.

The Retransfer to Startup function is provided to ensure that a single failure (associated with the standby source) does not cause the MFBs to remain deenergized. Should the standby source fail, then power will be supplied to the MFBs from the startup source when energized from the Keowee Unit aligned to the overhead. The Retransfer to Startup timers are set such that the maximum time the MFBs will be de-energize is 33 seconds. This time is derived from the maximum allowable Keowee "start and accelerate to speed" time (23 seconds) and the Retransfer to Startup timers (5 seconds).

(continued).

Oconee Units 1, 2, & 3 B 3.7-36 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Automatic Transfer Functions B 3.7.3 BASES (continued)

APPLICABLE The EPSL transfer functions are designed to perform their function assuming a worst SAFETY case credible single failure. There are two independent EPSL Automatic Transfer ANALYSIS channels. Each channel is capable of performing the entire transfer function.

(continued)

Channel A of the EPSL Automatic Transfer Function consists of channel A of the Load Shed and Transfer to Standby circuit and channel A of the Retransfer to Startup logic.

Channel B of the EPSL Automatic Transfer Function consists of channel B of the Load Shed and Transfer to Standby circuit and channel B of the Retransfer to Startup logic.

EPSL automatic transfer functions are part of the primary success path and functions to mitigate a DBA or transient that presents a challenge to the integrity of a fission product barrier. As such, EPSL automatic transfer functions satisfy the requirements of selection criterion 3 of 10 CFR 50.36 (Ref.1).

TS Two channels of both the Load Shed and Transfer to Standby function and Retransfer to Startup function are required to be OPERABLE. Implicit in this is all relays, contacts, power supplies, timers, etc., which are necessary for the circuit to perform its intended safety function, are OPERABLE. The single MFB undervoltage relay for each MFB is required to be OPERABLE or in the safe (dropped out) position for the associated Load Shed and Transfer to Standby channel to be OPERABLE. With one channel of either function inoperable, the remaining channel can still completely perform the intended safety function. However, a subsequent single failure could disable the remaining channel from performing its safety function.

APPLICABILITY The transfer functions of EPSL are required to be OPERABLE above COLD SHUTDOWN to ensure that power is provided from AC Sources to the AC Distribution system within the time assumed in the accident analyses.

ACTIONS A.1 In the event one channel of the EPSL Transfer functions becomes inoperable, then the remaining channel is fully capable of providing all necessary transfer functions to ensure power is provided to the MFBs. A single failure of the remaining channel could cause the main feeder buses to remain deenergized until operator action is taken to restore power. Therefore, a period of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed for restoration of any inoperable channel. The completion time is based on engineering judgement, taking into consideration the time required to complete the required action and the availability of the remaining channel.

(continued)

Oconee Units 1, 2, & 3 B 3.7-37 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Automatic Transfer Functions B 3.7.3 BASES (continued)

ACTIONS A. I (continued)

Channel A and B provide redundant transfer functions. The retransfer to startup function of each channel is actuated by its associated channel of transfer to standby function (through the RX relay).

Additionally, each channel of transfer functions provide a permissive in its associated SK breaker (through the RX relay) to allow its automatic closure (i.e., channel A with SKI channel B with SK2). Also, an S breaker can close automatically only when its associated bus is energized. If a channel of transfer to standby is inoperable then the associated RX relay may not be OPERABLE (depending on what portion of transfer to standby function is inoperable). This could keep the associated SK breaker from automatically closing and cause the associated retransfer to startup function to be inoperable. The remaining channel of transfer to standby function and retransfer to startup function needs to be OPERABLE to restore power during LOCA/LOOP events.

The S breaker associated with the OPERABLE transfer channel also needs to be OPERABLE, since the other S breaker may not be capable of automatically closing due to its standby bus being deenergized (SK breaker not closed).

For these reasons, transfer functions of the same channel are allowed to be inoperable only when both functions of the other channel are OPERABLE and the other channel's associated S breaker is OPERABLE (i.e., channel A with SI and channel B with S2).

B.1 and B.2 If the Required Actions and associated Completion Times cannot be met, the unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in the following 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . These times allow for a controlled shutdown of one or all three Units without placing undue stress on plant operators or plant systems.

SURVEILLANCE SR 3.7.3.1 REQUIREMENTS See Bases for SR 3.7.1.14 (EPSL automatic transfer).

REFERENCES 1. 10 CFR 50.36.

2. 4160V Auxiliary Power System DBD, OSS-0254.00-00-2000.

Oconee Units 1, 2, & 3 B 3.7-38 Amendment .2.32.__ Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Voltage Sensing Circuits B 3.7.4 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.4 Emergency Power Switching Logic (EPSL) Voltage Sensing Circuits BASES BACKGROUND The Emergency Power Switching Logic (EPSL) Voltage Sensing Circuits consist of the voltage sensing circuits for the Startup Source, Standby Bus #1, Standby Bus #2, and the Normal Source. These voltage sensing circuits provide input to the EPSL power seeking logic to actuate breakers and initiate transfer logic sequences. Each phase of each source has an individual potential transformer feeding a 2 out of 3 logic for determining the status of the power source. The voltage sensing circuits also provide class IE trip signals to the breaker control circuitry for the N, E, and SL breakers.

APPLICABLE The Safety Analysis for the voltage sensing circuits of EPSL is contained in Chapter SAFETY 8 and 15 of the FSAR. The EPSL system is designed to ensure power is supplied ANALYSES to the main feedwater buses (MFBs) during a design basis accident (DBA). In order for it to perform this function, the voltage sensing circuits for the Startup Source, Normal Source, Standby Bus #1, and Standby Bus #2 must be OPERABLE. These voltage sensing circuits provide input to the EPSL transfer functions. The transfer functions utilize the voltage sensing circuits to initiate breaker operations to ensure the MFBs are connected to an energized source (startup or standby).

EPSL voltage sensing circuits are part of the primary success path and function to mitigate a DBA or transient that presents a challenge to the integrity of a fission product barrier. As such, EPSL voltage sensing circuits satisfy the requirements of selection criterion 3 of 10 CFR 50.36 (Ref. 1).

APPLICABILITY The EPSL voltage sensing circuits are required to be OPERABLE above COLD SHUTDOWN to ensure that power is provided from AC Sources to the AC Distribution system within the time assumed in the accident analyses.

(continued)

Oconee Units 1,2, & 3 B 3.7-39 Amendment _231 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Voltage Sensing Circuits B 3.7.4

BASES (continued)

TS Three circuits (one per phase) for each power bus (Normal, Startup, Standby Bus #1, Standby Bus #2) must be OPERABLE. In addition, the relays and contacts that provide the input and output of the 2 out of 3 logic must be OPERABLE. These circuits and associated logic ensure that no credible single failure can cause a loss of any function required by the voltage sensing circuits.

The TS has been modified by a NOTE which removes Normal Source voltage sensing requirements when both N breakers are open. The safety function of the Normal Source Voltage Sensing circuits is to provide a safety related trip signal to the N breakers.

When the N breakers are open, the Normal source voltage Sensing Circuits do not perform a safety function and, therefore, need not be OPERABLE.

ACTIONS A NOTE has been included in the ACTIONS to allow separate Condition entry for each inoperable Voltage Sensing Circuit. Thus, Completion Times are tracked separately for each power bus (Normal, Startup, Standby Bus #1, Standby Bus #2).

A.1 In the event one channel (phase) of the voltage sensing circuit becomes inoperable, the circuit will still perform its intended function. However, with one channel inoperable, the voltage sensing function is reduced to 2 out of 2 logic. A single failure could make the voltage sensing function inoperable. With a voltage sensing function inoperable, EPSL transfer functions or breaker trip circuitry could be disabled such that Operator action would be required to reenergize the MFBs during accident conditions. For this reason 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed for repair of any inoperable channel of the voltage sensing function. The completion time is based on engineering judgement taking into consideration the time required to complete the required action and the availability of the remaining channels.

Note that one voltage sensing channel for each AC bus may be inoperable at the same time without loss of the voltage sensing function for any bus.

B.1 and B.2 If the Required Actions and associated Completion Times cannot be met, the unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in the following 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . These times allow for a controlled shutdown of one or all three Units without placing undue stress on plant operators or plant systems.

(continued)

Oconee Units 1, 2, & 3 B 3.7-40 Amendment _232. Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Voltage Sensing Circuits

BASES (continued)

B 3.7.4 SURVEILLANCE SR 3.7.4.1 REQUIREMENTS This surveillance verifies operability of each sensing circuit of each bus which can supply the MFBs. A circuit is defined as three channels, one for each phase. Each channel consists of all components from the sensing power transformer on the actual buswork through the circuit auxiliary relays which operate contacts in the EPSL logic and breaker trip circuits. Actual setpoint values for the undervoltage relays on the N and E breakers are verified independently as a prerequisite to this SR. Minimum requirements consist of individual channel relay operation causing appropriate contact responses within associated loadshed/breaker circuits, alarm activations, and proper indications for the sensing circuit control power status. The frequency for this SR is reasonable based on operating experience and the need to remove the bus from service to perform required testing.

REFERENCES 1. 10 CFR 50.36.

2. 4160V Auxiliary Power System DBD, OSS-0254.00-00-2000.

Oconee Units 1, 2, & 3 B 3.7-41 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Keowee Emergency Start Function B 3.7.5 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.5 Emergency Power Switching Logic (EPSL)

Keowee Emergency Start Function BASES BACKGROUND The Keowee Emergency Start function of EPSL provides a start signal to the two on-site emergency power sources and sets up logic and relaying for their use in the emergency mode. There are two independent channels of the Emergency Start function. Each channel is capable of starting both Keowee units and activating the logic for operating in the emergency mode.

The Emergency Start channels I and 2 are actuated from Engineered Safeguards channels I and 2 respectively. The Emergency Start channels can also be activated manually from the Oconee Control rooms or cable spread rooms. There are two independent channels associated with each Oconee unit.

APPLICABLE The safety analysis for EPSL and the emergency power system is contained in SAFETY Chapter 8 and 15 of the FSAR. The most severe Design Basis Accident (DBA) for the ANALYSES emergency power system is a LOCA with a Loss of Offsite Power (LOOP). For this transient the Keowee Emergency Start function of EPSL must send a start signal.to both Keowee units. Logic is also actuated that ensures separation of both Keowee units from the system grid. Alignment of the Keowee Unit connected to the overhead power path is allowed only after a separate logic sequence ("Switchyard Isolate Complete" which is not associated with the Keowee Emergency Start function) verifies the switchyard alignment is separated from the grid.

The Keowee Emergency Start function also disables non critical protective interlocks and trips associated with the Keowee generators. This is to help ensure the generators will remain available for emergency power despite minor failures or malfunctions.

The Keowee Emergency Start circuitry is designed such that no credible single failure can prevent an Emergency Start signal from reaching the Keowee units. Each channel is completely independent of the other and only one channel is required to perform the entire safety function.

EPSL Keowee Emergency Start Function is part of the primary success path and functions to mitigate a DBA or transient that presents a challenge to the integrity of a fission product barrier. As such, the EPSL Keowee Emergency Start Function satisfies the requirements of selection criterion 3 of 10 CFR 50.36 (Ref.1).

(continued)

Oconee Units 1, 2, & 3 B 3.7-42 Amendment 232 Unit I Amendment 232 Unit 2 Amendment Unit 3

EPSL Keowee Emergency Start Function B 3.7.5

BASES (continued)

TS Two channels of the Keowee Emergency Start function are required to be OPERABLE.

This includes all relays, contacts, and logic that are required to Emergency Start the Keowee units, bypass specific protective interlocks and trips, and circuitry that separates the Keowee units from the grid (trips ACBs I and 2). Portions of the two channels affect the Oconee Units individually.

APPLICABILITY The Keowee Emergency Start function of EPSL is required to be OPERABLE above COLD SHUTDOWN to ensure that power is provided from AC Sources to the AC Distribution system within the time assumed in the accident analyses.

ACTIONS A.1 In the event one channel of the Keowee Emergency Start function becomes inoperable, then a single failure of the other channel could prevent starting the Keowee units. For most scenarios, the Keowee Unit would still be emergency started by Operator action or automatically from non-class IE circuitry. For this reason, 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months is allowed for restoration of one inoperable channel. The Completion Time is based on engineering judgement taking into consideration the time required to complete the required action and the availability of the remaining channel. In addition, the Completion Time is consistent with TS 3.7.1 for one inoperable power path.

B.1 and B.2 If the Required Actions and associated Completion Times cannot be met, the unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in the following 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . These times allow for a controlled shutdown of one or all three Units without placing undue stress on plant operators or plant systems.

C.1 If both channels of the Keowee Emergency Start function become inoperable then both Keowee Hydro Units must be declared inoperable for the affected Oconee Unit(s).

Appropriate required actions are specified in TS 3.7.1 (AC Sources - Operating).

(continued)

Oconee Units 1, 2, & 3 B 3.7-43 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Keowee Emergency Start Function B 3.7.5 BASES (continued)

SURVEILLANCE SR 3.7.5.1 REQUIREMENTS See Bases for SR 3.7.1.11 (Keowee Emergency Start) and SR 3.7.1.14 (EPSL automatic transfer).

REFERENCES 1. 10 CFR 50.36.

2. 4160V Auxiliary Power System DBD, OSS-0254.00-00-2000.

3. Keowee Emergency Power System DBD, OSS-0254.00-00-2005.

Oconee Units 1, 2, & 3 B 3.7-44 Amendment 232 Unit 1 Amendment Unit 2 Amendment 231 Unit 3

EPSL Degraded Grid Voltage Protection B 3.7.6 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.6 Emergency Power Switching Logic (EPSL)

Degraded Grid Voltage Protection B3ASES BACKGROUND Two independent levels of protection are provided to assure the degradation of voltage from offsite sources does not adversely impact the function of safety-related systems and components. The first level of protection is provided by the EPSL Degraded Grid Protection System (DGPS). The second level of protection is provided by undervoltage relaying on the E and N breakers (reference TS 3.7.4, EPSL Voltage Sensing Circuits) which protects from loss of voltage.

The DGPS, upon indication of inadequate voltage, will provide an alarm to the Unit I &

2 Control room and the Spartanburg Dispatcher. If any single engineered safeguards (ES) Channel I or 2 signal from any Unit is sensed by the DGPS, while the voltage is below acceptable levels, the DGPS will initiate an isolation of the 230kV switchyard Yellow Bus to ensure the onsite overhead emergency power path is available. Each DGPS actuation logic channel is capable of isolating the overhead emergency power path by a set of 94V relays and the associated switchyard PCB trip coil. The sets of actuating (94V) relays are common to the DGPS and the undervoltage part of another system called the External Grid Trouble Protection System (EGTPS). The isolation of the yellow bus is accomplished by opening switchyard PCBs 8, 12, 15, 17, 21, 24, 26, 28, and 33. While the DGPS relaying could result in the unavailability of the overhead emergency power path, it does ensure that the startup transformers are not connected to a degraded source of power. In this event, ES loads are provided adequate voltage from the standby buses. The EGTPS serves to protect from grid collapse.

Based on historical data, it is anticipated any degradation of the voltage in the 230kV switchyard will not last for an extended period of time. Administrative procedures are in place to assure timely actions are taken to restore the voltage.

There are three undervoltage relays installed to monitor the switchyard voltage, one on each of the yellow bus phases. Each of the undervoltage relays is supplied by a single phase coupling-capacitor voltage transformer. The undervoltage relay contacts are arranged in a 2-out-of-3 logic sequence which feeds two redundant time delay (drop) relays. The time delay relays were added to prevent spurious actuations, but still provide adequate response time to voltage transients. Either of the two redundant time-delay relays will cause either of the two sets of actuating relays to initiate switchyard isolation.

The DGPS voltage sensing may be considered OPERABLE when in a tripped condition.

Circuit control power is fed from the 230kV Switchyard 125VDC system.

(continued)

Oconee Units 1, 2, & 3 B 3.7-45 Amendment 232 Unit I Amendment = Unit 2 Amendment 231 Unit 3

EPSL Degraded Grid Voltage Protection B 3.7.6 BASES (continued)

APPLICABLE The purpose of the DGPS is to ensure adequate voltage is available during an ES SAFETY actuation concurrent with a 230kV switchyard voltage of less than 226kV.

ANALYSES Based on design calculations, 226kV is the minimum switchyard voltage that will ensure proper operation of loads during ES actuation without being subject to damage or protective relay actuation.

EPSL Degraded Grid Voltage Protection is part of the primary success path and functions to mitigate a DBA or transient that presents a challenge to the integrity of a fission product barrier. As such, EPSL Degraded Grid Voltage Protection satisfies the requirements of selection criterion 3 of 10 CFR 50.36 (Ref. 1).

TS Three yellow bus sensing relays are required to be OPERABLE. The loss of power to any yellow bus phase deenergizes the associated sensing relay and satisfies part of the logic for system actuation. This reduces the logic to a 1-out-of-2 function; however, the tripped channel is considered to be OPERABLE since the affect is in the conservative direction. Loss of a second sensing relay will still have no effect on actuation except to satisfy the Degraded Grid permissive and leave only a single ES Channel I or 2 signal remaining to cause system actuation. Therefore, OPERABLE is defined as energized or tripped.

Both channels of Degraded Grid Voltage Protection Actuation Logic are required to be OPERABLE to ensure single failure criteria can be met while maintaining system function. The actuating 94V relays, which are shared with the voltage channels of the EGTPS and the associated switchyard PCB trip coils, are also considered part of the DGPS and are required to be OPERABLE. Therefore, loss of either 94V relay for the undervoltage channels also constitutes loss of one channel of DGPS. Similarly, loss of one required switchyard PCB trip coil constitutes loss of one channel of DGPS.

APPLICABILITY The DGPS is required to be OPERABLE above COLD SHUTDOWN to ensure a reliable and adequate power available to ES systems.

(continued)

Oconee Units 1,2, & 3 B 3.7-46 Amendment 232 Unit I Amendment Unit 2 Amendment 231L Unit 3

EPSL Degraded Grid Voltage Protection B 3.7.6 ASES (continued)

ACTIONS The Required Actions have been established based on the level of degradation of the DGPS.

A.1 If a single voltage sensing relay is inoperable, the relay must be placed in trip within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . Tripping the affected relay places the function in a 1-out-of-2 configuration.

Operation in this configuration may continue indefinitely since the DGPS function is capable of performing its function in the presence of a single failure. With one relay inoperable, the remaining relays are capable of providing the DGPS function. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months completion time is based on engineering judgement taking into consideration the infrequency of actual Grid system voltage degradation, the probability of a simultaneous ES actuation, and the availability of other Unit's sensing relays.

B.1 In the event one channel of actuation logic is inoperable (unable to trip) then a single failure of the other channel to trip when required would remove protection from a Degraded Grid condition concurrent with ES actuation. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months completion time to restore the inoperable channel is based on engineering judgement taking into consideration the infrequency of actual grid system degradation, the probability of a simultaneous ES actuation, and the availability of the OPERABLE channel.

C.1 and C.2 If the Required Actions and associated Completion Times for Condition A or B cannot be met, the unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in 84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months . These times allow for a controlled shutdown of one or all three Units without placing undue stress on plant operators or plant systems.

D.1 and D.2 Two or more voltage sensing relays inoperable or two actuation logic channels inoperable removes Degraded Grid Protection from being available to the Station during ES actuation. The loss of protection exposes any Unit to an inadequate power supply during a degraded grid situation concurrent with a LOCA on that Unit. In addition, the inoperability of the Degraded Grid Voltage Protection system prevents switchyard isolation during a LOCA. Since switchyard isolation is inoperable, the overhead emergency power path is declared inoperable in accordance with the requirements in Technical Specification 3.7.1. The Completion Times are based on engineering judgement taking into consideration the infrequency of actual grid system degradation, and the probability of a simultaneous ES actuation.

(continued)

Oconee Units 1, 2, & 3 B 3.7-47 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL Degraded Grid Voltage Protection B 3.7.6 WASES (continued)

SURVEILLANCE SR 3.7.6.1 REQUIREMENTS A CHANNEL CALIBRATION is a complete check of the instrument channel, including the sensor. The test verifies that the channel responds to the measured parameter within the necessary range and accuracy. CHANNEL CALIBRATION leaves the channel adjusted to account for instrument drift to ensure that the instrument channel remains operational between successive tests. CHANNEL CALIBRATION shall find that measurement errors and bistable setpoint errors are within the assumptions of the setpoint analysis. CHANNEL CALIBRATIONS must be performed consistent with the assumptions of the setpoint analysis.

The Frequency is justified by the assumption of an 18 month calibration interval in the determination of the magnitude of equipment drift in the setpoint analysis.

SR 3.7.6.2 A CHANNEL TEST is performed on each DGPS voltage sensing channel and DGPS actuation logic channel to ensure the entire channel will perform its intended function.

Any setpoint adjustments shall be consistent with the assumptions of the setpoint analysis. The CHANNEL TEST of the DGPS actuation logic channels includes verifying actuation of both channels of the switchyard isolation circuitry. The Frequency is based on engineering judgment and operating experience that determined testing on an 18 month interval provides. reasonable assurance that the circuitry is available to perform its safety function.

(continued)

REFERENCES 1. 10 CFR 50.36.

2. 230kV Switchyard Power System DBD, OSS-0254.00-00-2004.

Oconee Units 1, 2, & 3 B 3.7-48 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 27 Unit 3

EPSL CT-5 Degraded Grid Voltage Protection B 3.7.7 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.7 Emergency Power Switching Logic (EPSL)

CT-5 Degraded Grid Voltage Protection BASES BACKGROUND Two levels of protection are provided for the standby buses to assure that degradation of voltage from the 100kV transmission system through the Central Switchyard does not adversely impact the function of safety related systems and components. The first level of protection is provided by the EPSL CT-5 Degraded Grid Protection System. The second level of protection is provided by undervoltage relaying on the standby buses (reference TS 3.7.4, EPSL Voltage Sensing Circuits) which protects from loss of voltage.

APPLICABLE The purpose of the CT-5 Degraded Grid Protection System is to ensure adequate SAFETY voltage is available during a ES actuation concurrent with a loss of offsite power ANALYSES (LOOP) or degraded voltage from the 230 kV switchyard.

Based on design calculations, 93.23% is the minimum switchyard voltage that will ensure proper operation of loads during ES actuation without being subject to damage or protective relay actuation.

This system is only required when any Oconee Unit is above COLD SHUTDOWN and the Standby Buses are supplied by Central Switchyard. System design is to provide protection for ES components caused by voltage droop due to inrush as the ES unit ties to the Standby Buses.. The system is not a substitute for the dedicated line from Lee Gas Turbines used per TS 3.7.1. The Lee Feeder breakers (SL) have no automatic close functions. However, this system does provide additional flexibility for the Station electrical system and operators in available power source options.

When the standby buses are powered from the 100kV transmission system through the Central Switchyard, the EPSL CT-5 Degraded Grid Voltage Protection is part of the primary success path and functions to mitigate a DBA or transient that presents a challenge to the integrity of a fission product barrier. As such, EPSL CT-5 Degraded Grid Voltage Protection satisfies the requirements of selection criterion 3 of 10 CFR 50.36 (Reference 1).

TS All three of the undervoltage sensing relays (27CT5/A, B, C) are required as a common input device to both channels of actuating logic. In addition to the three phase undervoltage sensing relays, each channel requires one time-delay relay, one auxiliary relay, and one associated single phase undervoltage sensing relay (27SL1 or 2).

(continued)

Oconee Units 1, 2, & 3 B 3.7-49 Amendment 232 Unit I Amendment 232 Unit 2 Amendment Unit 3

EPSL CT-5 Degraded Grid Voltage Protection

, ASES (continued)

B 3.7.7 TS (continued) Each channel trip signal passes through a selector switch, which either allows or inhibits the trip signal, to actuate one trip coil in each SL breaker. Loss of the 27SL 1 or 2 relay makes the affected channel inoperable. Loss of two or more voltage sensing relays results in inoperability of both channels of actuation logic.

APPLICABILITY This system is required when the Standby Buses are energized by Central Switchyard and any Unit is above COLD SHUTDOWN. This ensures adequate voltage protection should an ES Unit be transferred to the Standby Bus during an event and coincides with requirements for ES and other support/protective systems used to ensure adequate power is available for core and containment protection.

ACTIONS- The Required Actions have been established based on the level of degradation of the Degraded Grid Protection System.

A.1 If a single voltage sensing relay is inoperable, the relay must be placed in trip within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . Tripping the affected relay places the function in a 1-out-of-2 configuration.

Operation in this configuration may continue indefinitely since the DGPS function is capable of performing its function in the presence of a single failure. With one relay inoperable, the remaining relays are capable of providing the DGPS function. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months completion time is based on engineering judgement taking into consideration the remaining OPERABLE undervoltage relays, the availability of the 230kV switchyard, the infrequency of actual Grid system voltage degradation, and the probability of a simultaneous ES actuation and loss of the 230kV switchyard.

B.1 In the event one channel of actuation logic is inoperable then a single failure of the other channel would remove protection from a degraded grid condition at the Central Switchyard concurrent with ES actuation and loss of the 230kV switchyard. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months completion time is based on engineering judgement taking into consideration the remaining OPERABLE channel of actuation logic, the availability of the 230kV switchyard, the infrequency of actual Grid system voltage degradation, and the probability of a simultaneous ES actuation and loss of the 230kV switchyard.

C.1 When two or more voltage sensing relays or both actuation logic channels are inoperable, there is no automatic protection from degraded grid voltage for the standby buses powered from the 100kV transmission system through the Central Switchyard.

EPSL response from ES events could be inhibited by Standby Bus voltage being allowed low enough to cause equipment damage, but not low enough for the EPSL standby (continued)

Oconee Units 1, 2, & 3 B 3.7-50 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

EPSL CT-5 Degraded Grid Voltage Protection B 3.7.7 BASES (continued)

ACTIONS C.1 (continued) bus undervoltage relays to cause breaker operation. Therefore, the standby buses must be separated from the 100kV transmission system within I hour. In addition, if the Required Actions and associated Completion Times cannot be met, the standby buses must be separated from the 100kV transmission system within I hour. This is accomplished by either opening both SL breakers, or by energizing both standby buses by an OPERABLE Lee gas turbine. If the standby buses are energized by an OPERABLE Lee gas turbine, the 100kV transmission circuit must be electrically separated from the system grid and all offsite loads. In addition, if the Required Actions and associated Completion Times cannot be met, the standby buses must be separated from the 100kV transmission system within I hour. This arrangement provides a high degree of reliability for the emergency power system. The one hour Completion Time is based on engineering judgement taking into consideration the availability of the 230kV switchyard, the infrequency of actual grid system voltage degradation, the probability of simultaneous ES actuation and loss of the 230kV switchyard, and the time to complete the Required Action.

SURVEILLANCE SR 3.7.7.1 REQUIREMENTS A CHANNEL CALIBRATION is a complete check of the instrument channel, including the sensor. The test verifies that the channel responds to the measured parameter within the necessary range and accuracy. CHANNEL CALIBRATION leaves the channel adjusted to account for instrument drift to ensure that the instrument channel remains operational between successive tests. CHANNEL CALIBRATION shall find that measurement errors and bistable setpoint errors are within the assumptions of the setpoint analysis. CHANNEL CALIBRATIONS must be performed consistent with the assumptions of the setpoint analysis.

The Frequency is justified by the assumption of an 18 month calibration interval in the determination of the magnitude of equipment drift in the setpoint analysis.

SR 3.7.7.2 A CHANNEL TEST is performed on each CT-5 DGPS voltage sensing channel and each CT-5 DGPS actuation logic channel to ensure the entire channel will perform its intended function. Any setpoint adjustments shall be consistent with the assumptions of the setpoint analysis. The Frequency is based on engineering judgment and operating experience that determined testing on an 18 month interval provides reasonable assurance that the circuitry is available to perform its safety function.

Oconee Units 1, 2, & 3 B 3.7-51 Amendment 232 Unit 1 Amendment _23T_ Unit 2 Amendment 231 Unit 3

EPSL CT-5 Degraded Grid Voltage Protection B 3.7.7 BASES (continued)

REFERENCES 1. 10 CFR 50.36.

2. Lee Emergency Power DBD, OSS-0254.00-00-2004 Oconee Units 1, 2, & 3 B 3.7-52 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

DC Sources - Operating B 3.7.8 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.8 DC Sources -Operating BASES BACKGROUND The 125VDC Vital Instrumentation and Control (I&C) Sources consist of 125VDC battery sources as described below. It provides control power for the Emergency Power System. It also provides both motive and control power to selected safety-related and non-safety equipment. It is designed to have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure.

For each unit, two independent and physically separated 125VDC batteries and buses are provided for the 125VDC Vital I&C Sources. The DC buses are two conductor metal clad distribution center assemblies. Three battery chargers are supplied for each unit, with two serving as normal supplies to the bus sections with the associated 125VDC battery floating on the bus. The batteries supply the load without interruption should the battery chargers or the AC source fail. Each of the three battery chargers is supplied from a separate 600 volt AC engineered safeguards motor control center. One of these three battery chargers serves as a standby battery charger and is provided for servicing and to back up the normal chargers. A bus tie with normally open breakers is provided between each pair of DC bus sections to "back up" a battery when it is removed for servicing. When the distribution centers are cross tied, the batteries and chargers on that Unit are considered to be a single source. One battery can supply both distribution centers and their associated panelboard loads.

During normal operation, the vital I&C 125VDC loads are powered from the battery chargers with the batteries floating on the system. Upon loss of AC power to the chargers, each unit's DC system has adequate stored capacity (ampere-hour) to independently supply required Emergency Loads for at least one hour. One hour is considered adequate, due to the high probability of restoring power to the charger within this time. The loss of all AC power to the DC system is expected to occur very infrequently and for short periods of time. Each battery charger has adequate power output capacity for the steady-state operation of connected loads required during normal operation, while at the same time maintaining its battery bank fully charged. Each battery charger has sufficient capacity to restore the battery to its fully charged state while supplying normal steady state loads.

In order to provide all safety functions required during an accident, power must be provided from any three of the four Vital I&C DC Power panelboards. During normal operation, the auctioneering network described above provides multiple redundancy for assuring that power from the 125VDC Vital I&C Sources would be provided to the Vital I&C DC Power panelboards. Therefore, power from any three of the four Vital I&C DC Sources for a particular unit (two for the unit considered, and two from the backup unit) continues to provide redundancy of power sources for safety functions performed by the Vital DC I&C Power panelboards.

(continued)

Oconee Units 1, 2, & 3 B 3.7-53 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 2 Unit 3

DC Sources - Operating OBASES (continued)

B 3.

7.8 BACKGROUND

The ungrounded DC system has detectors and alarms to indicate when there is a ground (continued) existing on any leg of the system. A ground on one leg of the DC system will not cause any equipment to malfunction. In order to find and correct a DC ground on the 125VDC Vital I&C System, each unit's DC Sources must be separated from the other two units.

With the backup function disabled, the unit would be in a degraded mode, but would in fact have all of its own DC Sources available if needed. Each unit's batteries (either CA or CB) is capable of carrying all the 125VDC instrumentation and control loads on that unit.

Unit I panelboards IDIC and IDID provide primary and backup power for SK and SL breakers control power, standby bus protective relaying control power, standby breakers control power for all three Units, and retransfer-to-startup source switching circuits for all three Oconee Unit's Emergency Power Switching Logic Systems. All other safety related functions supported by the Vital 125VDC Power panelboard are unit specific.

The 230kV Switchyard (SY) 125VDC Sources consists of 125VDC battery sources as described below. It provides primary and backup DC power for protective relaying and actuation circuits associated with the 230kV SY, as well as DC control power for 230kV SY power circuit breaker (PCB) operation. It is designed to have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure.

Safety functions provided by the 230kV SY 125VDC Sources include:

a) connection of on-site power from Keowee to Oconee via the emergency onsite overhead power path, and b) isolation of Oconee (including Keowee) from degraded grid voltage through action of the Degraded Grid Protection System (DGPS).

With the exception of the functions of the DGPS, all functions of the 230kV Switchyard DC Sources can be considered redundant to those associated with the emergency onsite underground power path.

There are two 125VDC batteries (SY-1; SY-2) in the 230kV SY Relay House, each with an associated battery charger. A spare charger, which can be connected to either battery, is also provided. These components, along with their interconnecting wiring and breakers, comprise the two 125VDC Sources for the 230kV SY.

Each 125VDC Source has stored capacity sufficient to supply required emergency loads for at least one hour. A one hour minimum capacity is considered adequate, due to the high probability of restoring power to the charger within this time. Each charger has power output capacity sufficient for steady-state operation of connected loads during normal operation, while simultaneously maintaining or restoring the associated battery bank to a fully charged condition.

(continued)

Oconee Units 1, 2, & 3 B 3.7-54 Amendment _.Z3Z.. Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

DC Sources - Operating OBASES (continued)

B 3.

7.8 BACKGROUND

The output of 230kV SY 125VDC Sources SY- 1 and SY-2 are connected to Distribution (continued) Centers SY-DC- I and SY-DC-2, respectively. The buses are metal-clad two conductor assemblies. A bus tie with normally open breakers is provided between the distribution centers to "backup" a battery when it is removed for servicing. SY-DC- I supplies DC Panelboards DYA, DYB, DYC, and DYD; SY-DC-2 supplies DC Panelboards DYE, DYF, DYG, and DYH. Distribution Centers SY-DC- 1 and SY-DC-2 with their associated safety-related DC panelboards and interconnecting wiring and breakers are included in the 230kV SY DC Sources.

The two distribution centers are redundant, each providing power to all components necessary for performing the safety functions of the 230kV SY DC Sources. DC Panelboard DYA is redundant to DYE; DYB is redundant to DYF, and DYC is redundant to DYG. Thus, the failure of any single component in the 230kV SY DC Distribution System, or in their associated 125VDC Sources, will not prevent any safety function from being performed. The redundant panelboards supply power to separate channels of the Degraded Grid Protection System (DGPS) circuits, separate channels of other protective relaying circuits, and separate feeds for each 230kV SY PCB's closing and tripping control. Separate dual trip coils are provided for each PCB. Isolating diodes are provided for redundant power feeds to each PCB's common closing coil circuit.

The ungrounded DC system has detectors and alarms to indicate when there is a ground existing on any leg of the system. A single ground will not cause any malfunction or prevent operation of any safety function.

APPLICABLE The initial conditions of design basis transient and accident analyses in FSAR Chapter SAFETY 6 (Engineered Safeguards) and Chapter 15 (Accident Analyses) include the assumption ANALYSES that all Engineered Safety Features are OPERABLE. The operability requirements of the 125VDC Vital I&C System are consistent with these assumptions, and are based upon meeting the design basis of the plant.

For an accident concurrent with a loss of all offsite power assuming a worst case single failure, the DC Sources provide power to components which function to maintain OPERABLE:

a. at least one of the onsite power sources (or offsite power sources, if available),

b. two ES power system strings,

c. at least three inverters, described in TS 3.7.9.

d. separate Oconee and the onsite power sources from the electrical system grid, should grid voltage be lost or degraded.

(continued)

Oconee Units 1, 2, & 3 B 3.7-55 Amendment 232 Unit I Amendment 232 Unit 2 Amendment -FITT Unit 3

DC Sources - Operating B 3.7.8 BASES (continued)

APPLICABLE The DC Sources provide emergency DC electrical power for control and switching of the SAFETY Emergency Power System, as well as DC power for other safety functions. It is part of ANALYSES the primary success path, functions to mitigate design basis accidents, and so meets (continued) selection criterion 3 of 10 CFR 50.36 (Reference 1).

TS For unrestricted operation, the four 125VDC I&C Power panelboards (DIA, DIB, DIC, &

DID) shall be OPERABLE. A panelboard is considered OPERABLE when it is energized from an OPERABLE source. In addition, no single source may be the only OPERABLE source of power to more than one panelboard.

A DC source is generally considered OPERABLE when TS 3.7.10 does not require the battery to be declared inoperable, and the battery bank and charger are connected to their associated bus and operating. For unrestricted operation, the following Vital I&C DC Sources shall be OPERABLE:

For operation of two or three Units, a total of five 125 VDC Vital Batteries, with associated chargers and distribution centers. Four 125 VDC Vital Batteries are adequate to ensure adequate capacity and voltage for the DC loads. Five batteries are required for single failure from a station DC loading perspective.

For operation of only one Unit, a total of four 125 VDC Vital Batteries, with associated chargers and distribution centers. Three 125 VDC Vital Batteries are adequate to ensure adequate capacity and voltage for the DC loads. Four batteries are required for single failure from a station DC loading perspective.

For a particular unit being considered, in association with its backup unit, a total of three of the four 125VDC Vital Batteries and associated chargers and distribution centers, including interconnections through their associated auctioneering diodes, as follows:

Unit 1: ICA, ICB, 2CA, 2CB Unit 2: 2CA, 2CB, 3CA, 3CB Unit 3: 3CA, 3CB, ICA, ICB In each case, one Vital I&C 125VDC Source associated with the unit being considered must be included. These requirements ensure that, for each operating unit, at least three Vital 125VDC Power panelboards will receive power, with adequate voltage, after sustaining any single failure in the 125VDC Vital I&C DC Sources.

For unrestricted operation, the two 230kV SY DC Distribution Centers (SY-DC-1; SY DC-2) shall be OPERABLE. For a distribution center to be considered OPERABLE, it must be energized from an OPERABLE source.

(continued)

Oconee Units 1,2, & 3 B 3.7-56 Amendment 232 Unit I Amendment 232 Unit 2 Amendment _2.31 Unit 3

DC Sources - Operating B 3.7.8 BASES (continued)

TS (continued) For unrestricted operation, two 230kV SY 125VDC Sources shall be OPERABLE. A DC source is generally considered OPERABLE when TS 3.7.10 does not require the battery to be declared inoperable, and the battery bank and charger are connected to their associated bus and operating.

The TS is modified by two NOTES. NOTE I indicates that the additional 125 VDC Vital I&C power sources required for operation of a single Unit or two or three Units are not required to be connected to the Units distribution system. For example, when only Unit I is in operation, the requirement that four batteries be OPERABLE can be met by ICA, ICB, 2CA and 3CA. The additional power sources are necessary to assure assumptions in the DC capacity and voltage drop analyses for the operating unit are valid. NOTE 2 indicates that the four 125 VDC Vital I&C power sources required during operation of a single Unit shall include one 125 VDC Vital I&C power source on each Unit which is not above COLD SHUTDOWN. The requirement that each shutdown unit have at least one of its own power sources is necessary to assure assumptions in the DC capacity and voltage drop analyses for the operating unit are valid.

APPLICABILITY The 125VDC Vital I&C System is required to be OPERABLE above COLD SHUTDOWN to support functions of the Engineered Safeguards System, the Reactor Protective System, the Emergency Power Switching Logic, and certain other safety functions.

ACTIONS The required actions have been established and based on the extent of degradation of the DC Sources.

A.1 and B.1 Conditions A and B can apply to one Unit or to two Units simultaneously. Specifically, if the Unit specific DC source requirements are not met due to the inoperability of one required DC source, Condition A or B would apply to that Unit. In addition, this could result in failure to meet the "fifth" source requirement of TS 3.7.8 for the station, or failure to meet the Unit specific requirements for another Unit. For example, if all three Units are above COLD SHUTDOWN, battery ICA is inoperable, and battery 3CB was on equalizing charge after the service test, two Units would be required to shutdown per Condition G if 3CB (or ICA) was not restored within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . With one of the required 125VDC Vital I&C Sources inoperable, the remaining sources are fully capable of providing adequate voltage to all 12 plant DC panelboards. In addition with one of the required DC sources inoperable, the remaining sources will assure alignment of power to at least three panelboards for the affected Unit. Three panelboards are necessary to shut down the operating unit and maintain it in a safe shutdown condition, assuming no single failure. However, overall reliability is reduced because a single failure in the remaining DC sources or one of the operating 125VDC Vital I&C Panelboards could result in the (continued)

Oconee Units 1,2, & 3 B 3.7-57 Amendment 232 Unit I Amendment 232 Unit 2 Amendment ___1 Unit 3

DC Sources - Operating B 3.7.8 BASES (continued)

ACTIONS A.1 and B.1 (continued) minimum required ES functions not being supported. Therefore, the inoperable source must be restored to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . A required battery may be inoperable for a period of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to perform equalizer charge following the performance test or service test(SR 3.7.8.3).

The completion times for actions in this TS are based on engineering judgment, taking into consideration the extent of degradation involved, the likelihood of events or failures which could challenge the system, and the time required to complete the required actions.

C.1 Inoperability of some of the Auctioneering Diode Panels (ADA 1, ADA2, ADB 1, ADB2, ADC1, ADC2, ADDI, ADD2), or a combination of inoperability of 125VDC Vital I&C Sources and auctioneering diode panels, could cause a single source to become the only battery power supply for more than one 125VDC Vital I&C Panelboard. In this condition, a single failure of that battery (or its associated equipment) could cause loss of more than one panelboard during an accident, so that required safety functions might not be supported. Specifically, if a single source were providing the only power source for panelboards DIA and DIB, single failure of the source would result in failure of both ES digital channels. Vulnerability of the ES digital channels to single failure for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is considered acceptable due to the limited scope of potential failures. Similarly, if the panelboards are isolated from their backup Unit (e.g., the Unit's DC system is isolated from the other Units), a single failure could result in loss of two or more panelboards so that required safety functions may not be supported. If the panelboards are isolated from their backup Unit when one of that Unit's batteries are inoperable (and the DC buses are cross tied), the remaining battery has the capacity to support all required loads, however a single failure could result in loss of all four panelboards so that required safety functions may not be supported. Therefore, within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after such a condition arises, affected equipment shall be restored and aligned such that no single source is the only battery power supply for more than one 125VDC Vital I&C Panelboard for the unit under consideration. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months completion time is based on engineering judgement taking into consideration the time to complete the Required Action and the redundancy available in the Vital I&C DC System.

D.1 Inoperability of some of the auctioneering diode panels (lADC1, IADC2, IADDI, and IADD2) or a combination of 125 VDC Vital I&C sources and auctioneering diode panels could cause a single source to become the only battery power supply for DC panelboards IDIC and IDID. This condition would impact all three Units since these panelboards provide primary and backup control power for the SK and SL breaker control power, standby bus protective relaying, standby breaker control power for all (continued)

Oconee Units 1, 2, & 3 B 3.7-58 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

DC Sources - Operating B 3.7.8 BASES (continued)

ACTIONS D.1 (continued) three Units, and retransfer to startup logic for all three Units. In this condition, a single failure of that battery (or its associated equipment) could cause loss of both panelboards, so that required automatic EPSL functions for all three units might not be supported.

Therefore, within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after such a condition arises, affected equipment shall be restored and aligned such that no single source is the only battery power supply for both DC panelboards IDIC and IDID. The completion time is based on engineering judgement taking into consideration the time to complete the required action and the redundancy available in the Vital I&C DC System.

A NOTE has been included to clarify that Condition D is not applicable to Unit 1.

Condition C applies to Unit 1. It is acceptable for Units 2 and 3 to be in Conditions C and D simultaneously since the IDIC and 1DID are not redundant to any Unit 2 or Unit 3 panelboards.

E.1 and F.1 With one of the required 230kV SY DC Sources inoperable, the remaining source is fully capable of providing adequate voltage to all connected panelboards, assuming no single failure. In addition, with one of the required DC sources inoperable, the remaining source is fully capable of powering the necessary panelboards, assuming no single failure. However, overall reliability is reduced because of the potential for a single failure in the remaining DC source or in a redundant panelboard. Loss of the remaining DC source or redundant panelboard could result in failure of the overhead emergency power path. In addition, in the event of grid degradation the station and onsite emergency power sources could fail to separate from the grid. Therefore, the inoperable source must be restored to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . A required battery may be inoperable for a period of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to perform equalizer charge following the performance test or service test (SR 3.7.8.3).

The completion times for actions in this TS are based on engineering judgment, taking into consideration the extent of degradation involved, the likelihood of events or failures which could challenge the system, and the time required to complete the required actions.

G.1 and G.2 If the Required Actions and associated Completion Times cannot be met, all three Units must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in the following 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . These times allow for a controlled shutdown of all three units without placing undue stress on plant operators or plant systems.

H.1 The inoperability of two or more required 125 VDC Vital I&C power sources or two 230kV switchyard 125VDC power sources could result in a loss of safety function.

Therefore, the provisions of TS 3.0 apply.

(continued)

Oconee Units 1, 2, & 3 B 3.7-59 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 2 3 1 Unit 3

DC Sources - Operating B 3.7.8 BASES (continued)

SURVEILLANCE SR 3.7.8.1 REQUIREMENTS Verifying battery voltage while on float charge helps ensure the effectiveness of the charging system and the ability of the battery to perform its intended function. Float charge is the condition where the charger is supplying continuous charge required to overcome the internal losses of the battery and maintain the battery in a fully charged state. The weekly frequency is consistent with manufacturers' recommendations and IEEE 450 (Ref. 2). The frequency is based on engineering judgement and industry accepted practice considering the unit conditions required to perform the test, the ease of performing the test and the likelihood of a change in system or component status.

SR 3.7.8.2 Measuring peak inverse voltage capability of each auctioneering diode ensures the diodes are capable of isolating a fault on one source from the other source. The 6 month frequency is based on engineering judgement and operating experience.

SR 3.7.8.3 The battery service test, in accordance with IEEE-450 (Ref. 2), demonstrates the capability of the battery to meet the system analyzed response requirements. Reference 3 provides the load requirements for the 125VDC I&C Batteries. The annual frequency is based on engineering judgement and industry-accepted practice considering the unit conditions required to perform the test, the ease of performing the test and the likelihood of a change in system or component status.

SR 3.7.8.4 Visual inspection of battery cells, end cell plates, and battery racks provide an indication of physical damage or abnormal deterioration which could potentially degrade battery performance. The annual frequency is based on engineering judgement and operational experience and is sufficient to detect battery degradation on a long-term basis when it is properly coupled with other surveillances more frequently performed to detect abnormalities.

SR 3.7.8.5 Verification of cell to cell connection cleanliness, tightness, and proper coating with anti-corrosion grease provides an indication of any abnormal condition, and assures continued operability of the battery. The annual frequency is based on engineering judgement and operational experience and is sufficient to detect cell connection degradation when it is properly coupled with other surveillances more frequently performed to detect abnormalities.

(continued)

Oconee Units 1, 2, & 3 B 3.7-60 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

DC Sources - Operating B 3.7.8

BASES (continued)

REFERENCES 1. 10 CFR 50.36.

2. IEEE 450-1980, IEEE Recommended Practice for Maintenance Testing and Replacement of Large Lead Storage Batteries for Generating Stations and Substations.

3. 125VDC Vital I&C System DBD, OSS-0254.00-00-2006.

4. Duke Design Engineering Calculation OSC-661, 230kV Switchyard Battery.

5. 230kV Switchyard 125 VDC Power System DBD, OSS-0254.00-00-2009.

Oconee Units 1, 2, & 3 B 3.7-61 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

Vital Inverters - Operating B 3.7.9 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.9 Vital Inverters - Operating BASES BACKGROUND The AC Vital Distribution System is comprised of four redundant 120VAC vital instrument power panelboards for each unit which provide power to associated vital instrumentation and control loads under all operating conditions. Each panelboard is powered separately from a static inverter connected to one of the four 125VDC instrumentation and control panelboards. In order to accommodate maintenance on the inverters and supply backup power, a tie with breakers is provided to each of the 120VAC vital panelboards from the alternate 120VAC regulated bus.

APPLICABLE The safety analysis for the vital inverters are contained in Chapters 8 and 15 of the SAFETY FSAR. All Engineered Safety Features (ESF) systems, which are powered by vital ANALYSES inverters, are assumed to be OPERABLE in the initial conditions of FSAR Chapter 6, (Engineered Safeguards), and 15, (Accident Analyses).

The vital inverters are part of the primary success path and functions to mitigate a DBA or transient that presents a challenge to the integrity of a fission product barrier. As such, the vital inverters satisfy the requirements of selection criterion 3 of the NRC interim policy statement (Ref.1).

TS All four vital inverters are required to be OPERABLE. Implicit in this is that all breakers and connecting hardware that are necessary for the circuit to perform its intended function are OPERABLE.

APPLICABILITY The vital inverters are required to be OPERABLE above COLD SHUTDOWN to assure that power is supplied to the ES and RPS systems.

(continued)

Oconee Units 1,2, & 3 B 3.7-62 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 23L. Unit 3

. BASES (continued)

ACTIONS A.1, A.2, and A.3 Vital Inverters - Operating B 3.7.9 In the event that vital inverter DIA or DIB is inoperable due to an inoperable inverter, a period of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed to connect the associated panelboard to the KRA regulated panelboard. The digital ES channels are powered from DIA and DIB, and cannot actuate without power. The 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months completion time is based on engineering judgement taking into consideration the time to complete the required action, the operability of redundant panelboards, and the low likelihood of an event requiring ES actuation.

Powering the associated panelboard (KVIA or KVIB) from KRA will ensure non-load shed power is available in the event of an accident. However, KRA is non-safety and not battery backed and could impact timing assumptions for ESF equipment during an accident since KRA must be reenergized following an assumed loss of offsite power (LOOP). Connecting to the KRA panelboard will restore power to the KVIA or KVIB panelboard, however KVIA or KVIB will still be considered inoperable in this condition and must be verified to be energized once each 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months completion time is based on engineering judgement taking.into consideration the operability of redundant panelboards, and the low likelihood of an event requiring ES with a concurrent LOOP.

The vital inverter must be returned to OPERABLE status within the next seven days. The completion time is based on engineering judgement taking into consideration the time to reasonably complete the required action, the operability of redundant panelboards, and the low likelihood of an event requiring ES with a concurrent LOOP.

B.1, B.2, and B.3 In the event that vital inverter DIC or DID is inoperable due to an inoperable inverter, a period of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed to connect the associated panelboard to the KRA regulated panelboard. This is based on the allowed inoperability period for a 125VDC instrument and control panelboard which is the normal power source to the vital inverters. Vital inverters DIC and DID carry loads which do not necessarily become inoperable upon loss of power, for example: RPS channels and ES analog channels which go to a tripped state upon loss of power. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months completion time is based on engineering judgement taking into consideration the time to complete the required action, the operability of redundant panelboards, and the low likelihood of an event requiring loads powered by DIC or DID.

Powering the associated panelboard (KVIC or KVID) from KRA will ensure non-load shed power is available in the event of an accident. However, KRA is non-safety and not battery backed and must be reenergized following an assumed LOOP. Connecting to the KRA panelboard will restore power to the KVIC or KVID panelboard; however, KVIC or KVID will still be considered inoperable in this condition and must be verified to be energized once each 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .completion time is based on engineering judgement taking into consideration the operability of redundant panelboards, and the low likelihood of an event requiring loads powered by DIC or DID.

(continued)

Oconee Units 1, 2, & 3 B 3.7-63 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

Vital Inverters - Operating B 3.7.9 BASES (continued)

ACTIONS B.1, B.2, and B.3 (continued)

The vital inverter must be returned to OPERABLE status within the next seven days. The completion time is based on engineering judgement taking into consideration the time to reasonably complete the required action, the operability of redundant panelboards, and the low likelihood of an event requiring loads powered by DIC or DID.

C.1 and C.2 If the required actions and associated completion times cannot be met, the unit must be in HOT SHUTDOWN in 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and COLD SHUTDOWN in the following 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

These times allow for a controlled shutdown on one or all three of the units without placing undue stress on plant operators or plant systems.

D.1 The inoperability of two or more AC Vital panelboards could result in a loss of safety function. Therefore, the provisions of TS 3.0 apply.

. SURVEILLANCE REQUIREMENTS SR 3.7.9.1 This SR verifies that the vital inverters are functioning properly with all required breakers closed and AC vital panelboards energized from the inverter. The verification of proper voltage and frequency ensures that the required power is readily available for the instrumentation connected to the panelboards. The weekly frequency takes into account the redundant capability of the panelboards and other indications available in the control room that will alert the operator to inverter malfunctions.

REFERENCES 1. 10 CFR 50.36.

Oconee Units 1,2, & 3 B 3.7-64 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

Battery Cell Parameters B 3.7.10 B 3.7 ELECTRICAL POWER SYSTEMS B 3.7.10 Battery Cell Parameters B3ASES BACKGROUND TS 3.7.10 (Battery Cell Parameters) delineates the limits on electrolyte temperature, level, float voltage, and specific gravity (or float current) for the Keowee Hydro Unit 125VDC, 125 VDC Vital I&C, and 230 kV 125 VDC power source batteries. A discussion of these batteries and their OPERABILITY requirements is provided in the Bases for TS 3.7.1, "AC Sources-Operating" and TS 3.7.8, "DC Sources-Operating."

APPLICABLE The initial conditions of accident and transient analyses in the FSAR, Chapter 6 (Ref. 1)

SAFETY and Chapter 15 (Ref. 2), assume Engineered Safeguards systems are OPERABLE.

ANALYSES The 125 VDC Vital I&C electrical power system provides normal and emergency DC electrical power for the emergency auxiliaries, and control and switching during all modes of operation.

Although the 230 kV Switchyard 125 VDC Power System provides control power for circuit breaker operation in the 230 kV switchyard as well as DC power for degraded grid voltage protection circuits during all modes of operation, no credit is taken for these functions when the Unit(s) are not above COLD SHUTDOWN.

Each Keowee Hydro Unit includes a 125 VDC power source to supply power to DC auxiliary loads and the Keowee Emergency Start circuits.

The OPERABILITY of the DC sources is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the unit. This includes maintaining necessary DC sources OPERABLE during accident conditions, in the event of:

a. An assumed loss of all offsite AC power or all onsite AC power; and

b. A worst-case single failure.

Battery cell parameters satisfy Criterion 3 of 10 CFR 50.36 (Ref. 3).

TS Battery cell parameters must remain within acceptable limits to ensure availability of the required DC power to shut down the reactor and maintain it in a safe condition after a transient or a postulated accident. Electrolyte limits are conservatively established, allowing continued DC electrical system function even with Category A and B limits not met.

(continued)

Oconee Units 1, 2, & 3 B 3.7-65 Amendment 2.3Z Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

. BASES (continued)

APPLICABILITY Battery Cell Parameters The battery cell parameters are required solely for the support of the associated DC B 3.7.10 electrical power sources. Therefore, battery cell parameters are only required to be met when the DC power source is required to be OPERABLE. Refer to the Applicability discussion in Bases for TS 3.7.1 and TS 3.7.8.

ACTIONS The ACTIONS Table is modified by a NOTE which indicates that separate Condition entry is allowed for each battery. This is acceptable, since the Required Actions for each Condition provides appropriate compensatory actions for each DC source. Complying with the Required Actions for one DC source may allow for continued operation, and subsequent DC source(s) are governed by separate Condition entry and application of associated Required Actions.

A second NOTE states that TS 3.7.0 is not applicable. This is acceptable since a battery remains OPERABLE when one or more cells does not meet Category A or B limits but continues to meet Category C limits. Failure to meet Category C limits requires declaring the associated battery inoperable. TS 3.7.0 requirements are applicable to the requirements of TS 3.7.8, "DC Sources - Operating" for an inoperable battery.

A.1, A.2, and A.3 With one or more cells in one or more batteries not within limits (i.e., Category A limits not met or Category B limits not met or Category A and B limits not met) but within the Category C limits specified in Table 3.7.10-1 in the accompanying TS, the battery is degraded but there is still sufficient capacity to perform the intended function.

Therefore, the affected battery is not required to be considered inoperable solely as a result of Category A or B limits not met, and continued operation is permitted for a limited period.

The pilot cell electrolyte level and float voltage are required to be verified to meet the Category C limits within I hour (Required Action A. 1). This check will provide a quick indication of the status of the remainder of the battery cells. One hour provides time to inspect the electrolyte level and to confirm the float voltage of the pilot cells. One hour is considered a reasonable amount of time to perform the required verification.

Verification that the Category C limits are met (Required Action A.2) provides assurance that during the time needed to restore the parameters to the Category A and B limits, the battery will still be capable of performing its intended function. A period of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed to complete the initial verification because specific gravity measurements must be obtained for each connected cell. Taking into consideration both the time required to perform the required verification and the assurance that the battery cell parameters are not severely degraded, this time is considered reasonable. The verification is repeated at 7 day intervals until the parameters are restored to Category A and B limits. This periodic verification is consistent with the normal Frequency of pilot cell surveillances.

(continued)

Oconee Units 1, 2, & 3 B 3.7-66 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

Battery Cell Parameters B 3.7.10

BASES (continued)

ACTIONS A.1, A.2, and A.3 (continued)

Continued operation is only permitted for 90 days before battery cell parameters must be restored to within Category A and B limits. With the consideration that, while battery capacity is degraded, sufficient.capacity exists to perform the intended function and to allow time to fully restore the battery cell parameters to normal limits, this time is acceptable prior to declaring the battery inoperable.

B.1 With the Required Action and associated Completion Time of Condition A not met, or one or more batteries with one or more battery cell parameters outside the Category C limit for any connected cell, or with the average electrolyte temperature of representative cells falling below 60 0 F, sufficient capacity to supply the maximum expected load requirement is not assured and the corresponding DC electrical power source must be declared inoperable immediately.

SURVEILLANCE SR 3.7.10.1 REQUIREMENTS This surveillance verification that Category A battery cell parameters are met is consistent with IEEE-450 (Ref. 4), which recommends regular battery inspections including voltage, specific gravity, and electrolyte level of pilot cells.

SR 3.7.10.2 This surveillance verification that Category B battery cell parameters are met is consistent with IEEE-450 (Ref. 4), which recommends quarterly battery inspections including voltage, specific gravity, and electrolyte level.

SR 3.7.10.3 This surveillance verification that the average temperature of representative cells (at least every sixth connected cell) is > 60*F is consistent with a recommendation of IEEE-450 (Ref. 4), which states that the temperature of electrolytes in representative cells should be determined on a quarterly basis. Lower than normal temperatures act to inhibit or reduce battery capacity. This surveillance ensures that the operating temperatures remain within an acceptable operating range. This limit is based on plant specific calculations.

(continued)

Oconee Units 1, 2, & 3 B 3.7-67 Amendment . Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

Battery Cell Parameters B 3.7.10 BASES (continued)

SURVEILLANCE Table 3.7.10-1 REQUIREMENTS (continued) This table delineates the limits on electrolyte level, float voltage, and specific gravity for three different categories. The meaning of each category is discussed below.

Category A defines the normal-parameter limit for each designated pilot cell in each battery. The cells selected as pilot cells are those whose temperature, voltage and electrolyte specific gravity are considered to approximate the state of charge of the entire battery.

The Category A limits specified for electrolyte level are based on manufacturer recommendations and are consistent with the guidance in IEEE-450 (Ref. 4), with the extra /4inch allowance above the high water level indication for operating margin to account for temperatures and charge effects. In addition to this allowance, footnote (a) to Table 3.7.10-1 permits the electrolyte level to be above the specified maximum level during equalizing charge, provided it is not overflowing. These limits ensure that the plates suffer no physical damage and that adequate electron transfer capability is maintained in the event of transient conditions. IEEE-450 (Ref. 4) recommends that electrolyte level readings should be made only after the battery has been at float charge for at least 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

The Category A limit specified for float voltage is > 2.13 V per cell. This value is based on a recommendation of IEEE-450 (Ref. 4), which states that prolonged operation of cells < 2.13 V can reduce the life expectancy of cells.

The Category A limit specified for specific gravity for each pilot cell is > 1.200 (0.015 below the manufacturer fully charged nominal specific gravity or a battery charging current that had stabilized at a low value). This value is characteristic of a charged cell with adequate capacity. According to IEEE-450 (Ref. 4), the specific gravity readings are based on a temperature of 77*F (25*C).

The specific gravity readings are corrected for actual electrolyte temperature and level.

For each 30F (1.67 0 C) above 77*F (25*C), I point (0.001) is added to the reading; I point is subtracted for each 3*F below 77 0 F. The specific gravity of the electrolyte in a cell increases with a loss of water due to electrolysis or evaporation.

Category B defines the normal parameter limits for each connected cell. The term "connected cell" excludes any battery cell that may be jumpered out.

The Category B limits specified for electrolyte level and float voltage are the same as those specified for Category A and have been discussed above. The Category B limit specified for specific gravity for each connected cell is the same as those specified for Category A and has been discussed above. In addition to that limit, it is required that the specific gravity for each connected cell must be no less than 0.0 10 below the average of all connected cells. These limits ensure that the effect of a highly charged or new cell does not mask overall degradation of the battery.

(continued)

Oconee Units 1, 2, & 3 B 3.7-68 Amendment 232 Unit 1 Amendment = Unit 2 Amendment 231 Unit 3

Battery Cell Parameters

. BASES (continued)

SURVEILLANCE REQUIREMENTS Table 3.7.10-1 (continued)

B 3.7.10 (continued) Category C defines the limits for each connected cell. These values, although reduced, provide assurance that sufficient capacity exists to perform the intended function and maintain a margin of safety. When any battery parameter is outside the Category C limits, the assurance of sufficient capacity described above no longer exists and the battery must be declared inoperable.

The Category C limits specified for electrolyte level (above the top of the plates and not overflowing) ensure that the plates suffer no physical damage and maintain adequate electron transfer capability. The Category C limits for float voltage is based on IEEE-450 (Ref. 4), which states that a cell voltage of 2.07 V or below, under float conditions and not caused by elevated temperature of the cell, indicates internal cell problems and may require cell replacement.

The Category C limits of average specific gravity is the same as those specified for Category A and has been discussed above.

The footnotes to Table 3.7.10-1 are applicable to Category A, B, and C specific gravity.

Footnote (b) to Table 3.7.10-1 requires the above mentioned correction for electrolyte level and temperature, with the exception that level correction is not required when battery float current is < 2 amps on float charge. This current provides, in general, an indication of overall battery condition.

Because of specific gravity gradients that are produced during the recharging process, delays of several days may occur while waiting for the specific gravity to stabilize. A stabilized charger current is an acceptable alternative to specific gravity measurement for determining the state of charge. This phenomenon is discussed in IEEE-450 (Ref. 4).

Footnote (c) to Table 3.7.10-1 allows the float (charger) current to be used as an alternate to specific gravity for a maximum of 7 days following a battery recharge. When battery float current is verified in lieu of specific gravity requirements, the specific gravity of each connected cell shall be measured prior to expiration of the 7 day allowance.

(continued)

Oconee Units 1,2, & 3 B 3.7-69 Amendment 232 Unit 1 Amendment 232 Unit 2 Amendment 231 Unit 3

. BASES (continued)

REFERENCES 1. FSAR, Chapter 6.

Battery Cell Parameters B 3.7.10

2. FSAR, Chapter 15.

3. 10 CFR 50.36.

4. IEEE-450-1995, Recommended Practice for Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Generating Stations and Substations.

5. 125VDC Vital I&C System DBD, OSS-0254.00-00-2006.

6. 230kV Switchyard 125VDC DBD, OSS-0254.00-00-2004.

Oconee Units 1,2, & 3 B3.7-70 Amendment Unit I Amendment Unit 2 Amendment 231 Unit 3

6.6.3 Special Reports Special reports shall be submitted to the Regional Administrator, Region II. within the time period specified for each report. These reports shall be submitted covering the activities identified below pursuant to the requirements of the applicable reference specification:

a. (Not Used)

b. (Not Used)

c. (Not Used)

d. Reactor Coolant System Surveillance, Inservice Inspection, Specification 4.2.1 Reactor Vessel Specimen, Specification 4.2.4

e. Reactor Building Surveillance, Containment Leakage Tests, Specification 4.4.1

f. Structural Integrity Surveillance, Tendon Surveillance, Specification 4.4.2.2

g. (Not Used)

h. (Not Used)

Oconee 1,2, and 3 6.6-5 Amendment 232 Unit I Amendment 232 Unit 2 Amendment 231 Unit 3

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