Text

Supplement to License Amendment Request Proposing Changes to Catawba and McGuire Technical Specification 3.8.1, AC Sources - Operating
	ML17325A588
Person / Time
Site:	Mcguire, Catawba, McGuire
Issue date:	11/21/2017
From:	Henderson K; Duke Energy Carolinas
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	RA-17-0051
	Download: ML17325A588 (151)
	v • d • e

Kelvin Henderson 526 S. Church Street Charlotte, NC 28202 Mailing Address:

EC07H / P.O. Box 1006 Charlotte, NC 28202 980.373.1295 Kelvin.Henderson@duke-energy.com Serial: RA-17-0051 10 CFR 50.90 November 21, 2017 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 CATAWBA NUCLEAR STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-413 AND 50-414 RENEWED LICENSE NOS. NPF-35 AND NPF-52 MCGUIRE NUCLEAR STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-369 AND 50-370 RENEWED LICENSE NOS. NPF-9 AND NPF-17

SUBJECT:

SUPPLEMENT TO LICENSE AMENDMENT REQUEST PROPOSING CHANGES TO CATAWBA AND MCGUIRE TECHNICAL SPECIFICATION 3.8.1, AC SOURCES - OPERATING

REFERENCES:

1. Duke Energy letter, License Amendment Request Proposing Changes to Catawba and McGuire Technical Specification 3.8.1, AC Sources - Operating, dated May 2, 2017 (ADAMS Accession No. ML17122A116).

2. Nuclear Regulatory Commission letter, McGuire Nuclear Station, Units 1 and 2 and Catawba Nuclear Station, Units 1 and 2 - Supplemental Information Needed for Acceptance of Requested Licensing Action RE: License Amendment Request Proposing Changes to Technical Specification 3.8.1, AC Sources - Operating (CAC Nos. MF9667 through MF9674, dated June 30, 2017 (ADAMS Accession No. ML17167A317).

3. Duke Energy letter, Supplement to License Amendment Request Proposing Changes to Catawba and McGuire Technical Specification 3.8.1, AC Sources - Operating, dated July 20, 2017 (ADAMS Accession No. ML17201Q132).

4. Nuclear Regulatory Commission letter, Catawba/McGuire - Acceptance of Requested Licensing Action Re: EDG AOT Extension/Shared Systems LAR (CACs MF9667 through MF9974), dated August 10, 2017 (ADAMS Accession No. ML17226A002).

Ladies and Gentlemen:

By letter dated May 2, 2017 (Reference 1), Duke Energy Carolinas, LLC (Duke Energy) submitted a License Amendment Request (LAR) for Catawba Nuclear Station (CNS), Units 1

U.S. Nuclear Regulatory Commission RA-17-0051 Page 2 and 2 and McGuire Nuclear Station (MNS), Units 1 and 2. The proposed change would extend the Completion Time for an inoperable diesel generator in Technical Specification (TS) 3.8.1, AC Sources - Operating at both stations. The proposed change would also alter the AC power source operability requirements for the Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES) (i.e., shared systems).

By letter dated June 30, 2017 (Reference 2), the Nuclear Regulatory Commission (NRC) requested supplemental information from Duke Energy. By letter dated July 20, 2017 (Reference 3), Duke Energy provided responses to the supplemental information request. The NRC concluded that Duke Energy did provide technical information in sufficient detail to enable the NRC staff to complete its detailed technical review and make an independent assessment regarding the acceptability of the proposed amendment in terms of regulatory requirements and the protection of public health and safety and the environment by letter dated August 10, 2017 (Reference 4).

A public meeting was held on September 20, 2017 between Duke Energy and the NRC staff to discuss the proposed change. Based on the meeting Duke Energy has decided to provide another supplement to the LAR in the Enclosure to this letter which revises the portion of the proposed change associated with AC power source operability requirements for shared systems. This revision to the proposed change is applicable to both CNS and MNS.

Specifically, two new Limiting Conditions for Operation (LCO) are proposed to be added to CNS and MNS TS 3.8.1. One new LCO reflects a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES (i.e., shared systems). The other new LCO reflects a DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES.

The Enclosure to this letter also provides additional technical information to support the proposed change specifically for CNS.

Attachments 1 and 2 provide revised TS markups for CNS and MNS to reflect the proposed change. Attachments 3 and 4 provide the CNS and MNS TS Bases pages marked up to reflect the proposed change (for information only). The TS Bases changes will be processed after LAR approval under the TS Bases Control Program for CNS and MNS.

The conclusions of the original Significant Hazards Consideration Determination and Environmental Considerations contained in the May 2, 2017 LAR (Reference 1) are unaffected as a result of this LAR supplement.

This document contains no new regulatory commitments.

U.S. Nuclear Regulatory Commission RA-17-0051 Page 3 Should you have any questions concerning this letter, or require additional information, please contact Art Zaremba at 980-373-2062.

I declare under penalty of perjury that the foregoing is true and correct. Executed on November 21 , 2017.

Kelvin Henderson Senior Vice President, Nuclear Corporate

Enclosure:

License Amendment Request Supplemental Information Attachments:

1. Revised Catawba Technical Specification Marked Up Pages

2. Revised McGuire Technical Specification Marked Up Pages

3. Revised Catawba Technical Specification Bases Marked Up Pages (For Information Only)

4. Revised McGuire Technical Specification Bases Marked Up Pages (For Information Only)

U.S. Nuclear Regulatory Commission RA-17-0051 Page 4 cc:

C. Haney, Region II Administrator U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Avenue NE, Suite 1200 Atlanta, GA 30303-1257 M. Mahoney, Project Manager (CNS and MNS)

U.S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 8 G9A Rockville, MD 20852-2738 J.D. Austin NRC Senior Resident Inspector Catawba Nuclear Station G.A. Hutto NRC Senior Resident Inspector McGuire Nuclear Station S.E. Jenkins, Manager Radioactive & Infectious Waste Management Division of Waste Management SC Dept. of Health and Env. Control 2600 Bull St.

Columbia, SC 29201 W.L. Cox, III, Section Chief Div. of Environmental Health, RP Section NC Dept. of Env. & Natural Resources 1645 Mail Service Center Raleigh, NC 27699-1645

U.S. Nuclear Regulatory Commission RA-17-0051 Page 5 bcc:

M.C. Nolan A.H. Zaremba J.L. Vaughan R.I. Rishel ELL File: (Corporate)

T. Simril C.E. Curry L.A. Keller C. Bigham C.A. Fletcher A. Michalski NCMPA-1 PMPA NCEMC T. Lowery (For CNS Licensing/Nuclear Records)

CNS Master File 801.01 - CN04DM S.D. Capps N.E. Kunkel S. Snider J. Glenn J. Thomas J.F. Hussey L. Hentz P. Howell (For MNS Licensing/Nuclear Records)

MNS Master File 801.01 - MG02DM

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 1 Enclosure License Amendment Request Supplemental Information

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 2

1. DESCRIPTION OF THE PROPOSED CHANGE (REVISED)

The proposed change submitted May 2, 2017 (ADAMS Accession No. ML17122A116) to modify Catawba (CNS) and McGuire Nuclear Station (MNS) Technical Specification (TS) 3.8.1, AC Sources - Operating, is being revised in the following sections to reflect two new Limiting Conditions for Operation (LCO). The first new LCO reflects a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES) (i.e., shared systems). The other new LCO reflects a diesel generator (DG) from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES. Corresponding Conditions, Required Actions (RA) and Completion Times are also being proposed for both CNS and MNS. The changes that are presented in this Enclosure and that are also reflected in Attachments 1 and 2, supersede the requested TS 3.8.1 changes from the original May 2, 2017 amendment request submittal entirely.

The TS revisions presented below for CNS and MNS are similar in content and structure to TS 3.8.1, AC Sources - Operating for Calvert Cliffs Nuclear Power Plant.

Note: The requirement for shared systems to have both an operable normal and emergency power supply in order to be considered operable is still proposed to be deleted from the CNS and MNS TS Bases.

1.1 Catawba Technical Specification 3.8.1 Change Request CNS TS 3.8.1 will be revised as follows and the TS markups that reflect the proposed change are contained in Attachment 1.

A new LCO 3.8.1.c is added that states: One qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES); and A new LCO 3.8.1.d is added that states: One DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES; A Note is added to the APPLICABILITY that states: The opposite unit electrical power sources in LCO 3.8.1.c and LCO 3.8.1.d are not required to be OPERABLE when the associated shared systems are inoperable.

Condition A is revised to state: One LCO 3.8.1.a offsite circuit inoperable.

Required Action A.1 is revised to state: Perform SR 3.8.1.1 for required OPERABLE offsite circuit(s).

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 3 The Completion Time (CT) for existing RA A.3 is revised to state:

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months AND 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b Condition B is revised to state: One LCO 3.8.1.b DG inoperable.

A new RA B.1 with an AND connector and the associated CT are inserted as follows:

B.1 Verify both DGs on the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months opposite unit OPERABLE.

AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND The existing RA B.1 is renamed B.2 and is revised to state: Perform SR 3.8.1.1 for the required offsite circuit(s).

The existing RA B.2 is renamed B.3.

The existing RA B.3.1 is renamed B.4.1 and is revised to state: Determine OPERABLE DG(s) is not inoperable due to common cause failure.

The existing RA B.3.2 is renamed B.4.2 and is revised to state: Perform SR 3.8.1.2 for OPERABLE DG(s).

A new RA B.5 with an AND connector and associated CT are inserted as follows:

B.5 Ensure availability of Prior to entering the Emergency Supplemental extended Completion Power Source (ESPS). Time of ACTION B.6 AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 4 The existing RA B.4 is renamed B.6. The associated CT is revised to state:

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from discovery of unavailable ESPS AND 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from discovery of unavailable ESPS when in extended Completion Time AND 14 days AND 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b New Condition C and associated RAs and CT is added as follows:

C. Required Action and C.1.1 Restore both DGs on the 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion opposite unit to Time of Required Action OPERABLE status.

B.1 not met.

OR C.1.2 Restore LCO 3.8.1.b DG to OPERABLE status.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 5 New Condition D and associated RAs and CTs is added as follows:

D. LCO 3.8.1.c offsite -------------------NOTE------------------

circuit inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems Operating," when Condition D is entered with no AC power source to a train.

D.1 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND D.2 Declare NSWS, CRAVS, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from CRACWS or ABFVES with discovery of no no offsite power available offsite power to one inoperable when the train concurrent with redundant NSWS, CRAVS, inoperability of CRACWS or ABFVES is redundant required inoperable. feature(s)

AND D.3 Declare NSWS, CRAVS, 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CRACWS and ABFVES supported by the inoperable offsite circuit inoperable.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 6 New Condition E and associated RAs and CTs is added as follows:

E. LCO 3.8.1.d DG -------------------NOTE------------------

inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems Operating," when Condition E is entered with no AC power source to a train.

E.1 Verify both LCO 3.8.1.b 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months DGs OPERABLE, the opposite units DG AND OPERABLE and ESPS available. Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND E.2 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND E.3 Declare NSWS, CRAVS, 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from CRACWS or ABFVES discovery of supported by the Condition E inoperable DG inoperable concurrent with when the redundant inoperability of NSWS, CRAVS, CRACWS redundant required or ABFVES is inoperable. feature(s)

AND

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 7 E. (continued) E.4.1 Determine OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months DG(s) is not inoperable due to common cause failures.

OR E.4.2 Perform SR 3.8.1.2 for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months OPERABLE DG(s).

AND E.5 Declare NSWS, CRAVS, 14 days CRACWS or ABFVES supported by the inoperable DG inoperable.

New Condition F and associated RAs and CT is added as follows:

F. Required Action and F.1.1 Restore both LCO 3.8.1.b 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion DGs and opposite units Time of Required Action DG to OPERABLE status E.1 not met. and ESPS to available status.

OR F.1.2 Restore LCO 3.8.1.d DG to OPERABLE status.

OR F.1.3 Declare NSWS, CRAVS, CRACWS and ABFVES supported by the inoperable DG inoperable.

Existing Condition C is renamed G and is revised to state:

Two LCO 3.8.1.a offsite circuits inoperable.

OR One LCO 3.8.1.a offsite circuit that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and the required LCO 3.8.1.c offsite circuit inoperable.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 8 Existing RA C.1 is renamed G.1 and the associated CT is revised to state: 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months from discovery of Condition G concurrent with inoperability of redundant required features Existing RA C.2 is renamed G.2.

Existing Condition D is renamed H and is revised to state:

One LCO 3.8.1.a offsite circuit inoperable.

AND One LCO 3.8.1.b DG inoperable.

The Note above existing RA D.1 is revised to state: Enter applicable Conditions and Required Actions of LCO 3.8.9, Distribution Systems - Operating, when Condition H is entered with no AC power source to any train.

Existing RA D.1 is renamed H.1 and existing RA D.2 is renamed H.2.

Existing Condition E is renamed I and is revised to state:

Two LCO 3.8.1.b DGs inoperable.

OR LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and LCO 3.8.1.d DG inoperable.

Existing RA E.1 is renamed I.1.

Existing Condition F is renamed J. Existing RA F.1 is renamed J.1.

Existing Condition G is renamed K and is revised to state:

Required Action and associated Completion Time of Condition A, C, F, G, H, I, or J not met.

OR Required Action and associated Completion Time of Required Action B.2, B.3, B.4.1, B.4.2, or B.6 not met.

OR Required Action and associated Completion Time of Required Action E.2, E.3, E.4.1, E.4.2, or E.5 not met.

Existing RA G.1 is renamed K.1. Existing RA G.2 is renamed K.2.

Existing Condition H is renamed L and is revised to state: Three or more LCO 3.8.1.a and LCO 3.8.1.b AC sources inoperable.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 9 Existing RA H.1 is renamed L.1.

A new NOTE is added at the beginning of the SURVEILLANCE REQUIREMENTS section of TS 3.8.1 which states: SR 3.8.1.1 through SR 3.8.1.20 are only applicable to LCO 3.8.1.a and LCO 3.8.1.b AC sources. SR 3.8.1.21 is only applicable to LCO 3.8.1.c and LCO 3.8.1.d AC sources.

New Surveillance Requirement (SR) 3.8.1.21 and associated Frequency is added as follows:

SR 3.8.1.21 For the LCO 3.8.1.c and LCO 3.8.1.d AC electrical In accordance with sources, SR 3.8.1.1, SR 3.8.1.2, SR 3.8.1.4, SR 3.8.1.5, the Surveillance and SR 3.8.1.6 are required to be met. Frequency Control Program 1.2 McGuire Technical Specification 3.8.1 Change Request MNS TS 3.8.1 will be revised as follows and the TS markups that reflect the proposed change are contained in Attachment 2.

A new LCO 3.8.1.c is added that states: One qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES); and A new LCO 3.8.1.d is added that states: One DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES; A Note is added to the APPLICABILITY that states: The opposite unit electrical power sources in LCO 3.8.1.c and LCO 3.8.1.d are not required to be OPERABLE when the associated shared systems are inoperable.

Condition A is revised to state: One LCO 3.8.1.a offsite circuit inoperable.

Required Action A.1 is revised to state: Perform SR 3.8.1.1 for required OPERABLE offsite circuit(s).

The Completion Time (CT) for existing RA A.3 is revised to state:

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months AND 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b Condition B is revised to state: One LCO 3.8.1.b DG inoperable.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 10 A new RA B.1 with an AND connector and associated CT are inserted as follows:

B.1 Verify LCO 3.8.1.d DG 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months OPERABLE.

AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND The existing RA B.1 is renamed B.2 and is revised to state: Perform SR 3.8.1.1 for the required offsite circuit(s).

The existing RA B.2 is renamed B.3.

The existing RA B.3.1 is renamed B.4.1 and is revised to state: Determine OPERABLE DG(s) is not inoperable due to common cause failure.

The existing RA B.3.2 is renamed B.4.2 and is revised to state: Perform SR 3.8.1.2 for OPERABLE DG(s).

A new RA B.5 with an AND connector and associated CT are inserted as follows:

B.5 Ensure availability of Prior to entering the Emergency Supplemental extended Completion Power Source (ESPS). Time of ACTION B.6 AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 11 The existing RA B.4 is renamed B.6. The associated CT is revised to state:

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from discovery of unavailable ESPS**

AND 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from discovery of unavailable ESPS when in extended Completion Time AND 14 days AND 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b New Condition C and associated RAs and CT is added as follows:

C. Required Action and C.1.1 Restore LCO 3.8.1.d DG to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion OPERABLE status.

Time of Required Action B.1 not met. OR C.1.2 Restore LCO 3.8.1.b DG to OPERABLE status.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 12 New Condition D and associated RAs and CTs is added as follows:

D. LCO 3.8.1.c offsite -------------------NOTE------------------

circuit inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems Operating," when Condition D is entered with no AC power source to a train.

D.1 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND D.2 Declare NSWS, CRAVS, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from CRACWS or ABFVES with discovery of no no offsite power available offsite power to one inoperable when the train concurrent with redundant NSWS, CRAVS, inoperability of CRACWS or ABFVES is redundant required inoperable. feature(s)

AND D.3 Declare NSWS, CRAVS, 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CRACWS and ABFVES supported by the inoperable offsite circuit inoperable.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 13 New Condition E and associated RAs and CTs is added as follows:

E. LCO 3.8.1.d DG -------------------NOTE------------------

inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems Operating," when Condition E is entered with no AC power source to a train.

E.1 Verify both LCO 3.8.1.b 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months DGs OPERABLE and ESPS available. AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND E.2 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND E.3 Declare NSWS, CRAVS, 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from CRACWS or ABFVES discovery of supported by the Condition E inoperable DG inoperable concurrent with when the redundant inoperability of NSWS, CRAVS, CRACWS redundant required or ABFVES is inoperable. feature(s)

AND

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 14 E. (continued) E.4.1 Determine OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months DG(s) is not inoperable due to common cause failures.

OR E.4.2 Perform SR 3.8.1.2 for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months OPERABLE DG(s).

AND E.5 Declare NSWS, CRAVS, 14 days CRACWS and ABFVES supported by the inoperable DG inoperable.

New Condition F and associated RAs and CT is added as follows:

F. Required Action and F.1.1 Restore both LCO 3.8.1.b 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion DGs to OPERABLE status Time of Required Action and ESPS to available E.1 not met. status.

OR F.1.2 Restore LCO 3.8.1.d DG to OPERABLE status.

OR F.1.3 Declare NSWS, CRAVS, CRACWS and ABFVES supported by the inoperable DG inoperable.

Existing Condition C is renamed G and is revised to state:

Two LCO 3.8.1.a offsite circuits inoperable.

OR One LCO 3.8.1.a offsite circuit that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and the required LCO 3.8.1.c offsite circuit inoperable.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 15 Existing RA C.1 is renamed G.1 and the associated CT is revised to state: 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months from discovery of Condition G concurrent with inoperability of redundant required features Existing RA C.2 is renamed G.2.

Existing Condition D is renamed H and is revised to state:

One LCO 3.8.1.a offsite circuit inoperable.

AND One LCO 3.8.1.b DG inoperable.

The Note above existing RA D.1 is revised to state: Enter applicable Conditions and Required Actions of LCO 3.8.9, Distribution Systems - Operating, when Condition H is entered with no AC power source to any train.

Existing RA D.1 is renamed H.1 and existing RA D.2 is renamed H.2.

Existing Condition E is renamed I and is revised to state:

Two LCO 3.8.1.b DGs inoperable.

OR LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and LCO 3.8.1.d DG inoperable.

Existing RA E.1 is renamed I.1.

Existing Condition F is renamed J. Existing RA F.1 is renamed J.1.

Existing Condition G is renamed K and is revised to state:

Required Action and associated Completion Time of Condition A, C, F, G, H, I, or J not met.

OR Required Action and associated Completion Time of Required Action B.2, B.3, B.4.1, B.4.2, or B.6 not met.

OR Required Action and associated Completion Time of Required Action E.2, E.3, E.4.1, E.4.2, or E.5 not met.

Existing RA G.1 is renamed K.1. Existing RA G.2 is renamed K.2.

Existing Condition H is renamed L and is revised to state: Three or more LCO 3.8.1.a and LCO 3.8.1.b AC sources inoperable.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 16 Existing RA H.1 is renamed L.1.

A new NOTE is added at the beginning of the SURVEILLANCE REQUIREMENTS section of TS 3.8.1 which states: SR 3.8.1.1 through SR 3.8.1.20 are only applicable to LCO 3.8.1.a and LCO 3.8.1.b AC sources. SR 3.8.1.21 is only applicable to LCO 3.8.1.c and LCO 3.8.1.d AC sources.

New Surveillance Requirement (SR) 3.8.1.21 and associated Frequency is added as follows:

SR 3.8.1.21 For the LCO 3.8.1.c and LCO 3.8.1.d AC electrical In accordance with sources, SR 3.8.1.1, SR 3.8.1.2, SR 3.8.1.4, SR 3.8.1.5, the Surveillance and SR 3.8.1.6 are required to be met. Frequency Control Program

2. TECHNICAL EVALUATION The NSWS, CRAVS, CRACWS and ABFVES (LCOs 3.7.8, 3.7.10, 3.7.11 and 3.7.12 respectively for CNS and LCOs 3.7.7, 3.7.9, 3.7.10 and 3.7.11 respectively for MNS) require certain components on both CNS and MNS units to be OPERABLE in Modes 1, 2, 3 and 4. A CRAVS fan that is powered from Unit 2, for example, could be required for Unit 1. Therefore, these systems are classified as shared systems for the AC electrical power requirements. The term shared systems for CNS and MNS is defined as the shared components of Train A or Train B of the NSWS, CRAVS, CRACWS and ABFVES. The CNS and MNS shared systems were described in Duke Energys supplemental response letter dated July 20, 2017 (ADAMS Accession No. ML17201Q132). Since the qualified offsite circuits and dedicated DGs not only provide support to their specified unit, but also can support shared systems, the two new LCOs proposed in Section 1 above for power sources that are aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of shared systems are provided to reflect this dependency in the Technical Specifications in order to fully satisfy the intent of 10 CFR 50.36. These new LCO requirements (designated LCO 3.8.1.c and LCO 3.8.1.d), in conjunction with the requirements for the applicable unit (or unit-specific) AC electrical power sources in LCO 3.8.1.a and LCO 3.8.1.b, ensure that power is available to two trains of the NSWS, CRAVS, CRACWS and ABFVES. The new LCOs also support removal of the requirement in the CNS and MNS TS Bases for shared systems (NSWS, CRAVS, CRACWS and ABFVES) to have both a normal and emergency power supply in order to be considered operable.

Specific technical justification for each aspect of the proposed change is provided below for Catawba (Section 2.1) and McGuire (Section 2.2) and will be presented in the same order that was used in Sections 1.1 and 1.2 to describe the TS 3.8.1 change requests.

2.1 Catawba Evaluation of the TS 3.8.1 Change Request In order to continue to meet Criterion 3 of 10 CFR 50.36 with the removal of the requirement from the CNS TS Bases to maintain both normal and emergency power for operability of the shared systems (NSWS, CRAVS, CRACWS and ABFVES), the opposite units AC power sources that are necessary to support the NSWS, CRAVS, CRACWS and ABFVES are incorporated into TS 3.8.1 within new LCOs 3.8.1.c and 3.8.1.d. Each train of NSWS, CRAVS,

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 17 CRACWS and ABFVES is connected to an onsite Class 1E electrical power distribution subsystem from either unit. The word necessary used in LCO 3.8.1.c and LCO 3.8.1.d clarifies that the respective AC power source is aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of shared systems. For example, in a normal alignment at CNS, Unit 1 Essential Bus 1ETA supplies Train A of shared systems and Unit 2 Essential Bus 2ETB supplies Train B of shared systems. Thus for this normal plant configuration, the 2B offsite circuit and 2B DG, both of which supply power to 2ETB, would be LCO 3.8.1.c and LCO 3.8.1.d AC sources for Unit 1 TS 3.8.1. Similarly, the 1A offsite circuit and 1A DG, both of which supply power to 1ETA, would be LCO 3.8.1.c and LCO 3.8.1.d AC sources for Unit 2 TS 3.8.1. However, since the 2A offsite circuit and 2A DG are not necessary to supply power to a train of shared systems in the normal plant configuration, they would not be LCO 3.8.1.c and LCO 3.8.1.d AC sources. And since the 1B offsite circuit and 1B DG are not necessary to supply power to a train of shared systems in the normal plant configuration, they would not be LCO 3.8.1.c and LCO 3.8.1.d AC sources. It is important to note that if desired or required to maintain operability, Train A shared equipment can be swapped to receive power from Unit 2 Essential Bus 2ETA. Similarly, Train B shared equipment can be swapped to receive power from Unit 1 Essential Bus 1ETB.

The Note that is added to the Applicability section takes exception to the requirements for the required AC sources in LCO 3.8.1.c and LCO 3.8.1.d provided the associated shared systems are inoperable. This exception is intended to allow declaring the shared systems supported by the opposite unit inoperable either in lieu of declaring the LCO 3.8.1.c and LCO 3.8.1.d AC sources inoperable, or at any time subsequent to entering ACTIONS for an inoperable LCO 3.8.1.c or LCO 3.8.1.d AC source. This exception is acceptable since, with the shared systems supported by the opposite unit inoperable and the associated ACTIONS entered, the LCO 3.8.1.c and LCO 3.8.1.d AC sources provide no additional assurance that acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of abnormal transients and also provide no additional assurance that adequate core cooling is provided and containment operability and other vital functions are maintained in the event of a postulated design basis accident (DBA).

Adding LCO 3.8.1.a to Condition A clarifies that the Condition pertains to a qualified circuit between the offsite transmission network and the Onsite Essential Auxiliary Power System rather than a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System.

Changing OPERABLE offsite circuit to required OPERABLE offsite circuit(s) in RA A.1 reflects that it could be necessary to verify the operability of more than one offsite circuit when a LCO 3.8.1.a offsite circuit is inoperable, since an offsite circuit may be aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of the NSWS, CRAVS, CRACWS and ABFVES (i.e., a LCO 3.8.1.c offsite circuit).

The proposed maximum CT of 17 days for RA A.3 limits the total time that LCO 3.8.1.a or LCO 3.8.1.b is not met while concurrently or simultaneously in Conditions A and B. The existing CT is the sum of the CT for RA A.3 (i.e., 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ) and existing RA B.4 (i.e., 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ). CNS is proposing to increase the CT for existing RA B.4 to 14 days; thus the maximum CT for RA A.3 will be increased from 6 days to 17 days.

Adding LCO 3.8.1.b to Condition B clarifies that the Condition pertains to unit-specific DG rather than a DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 18 New RA B.1 provides assurance that both opposite unit DGs are operable when a LCO 3.8.1.b DG is inoperable.

Renaming RAs B.1, B.2, B.3.1, B.3.2 and B.4 are administrative changes.

OPERABLE DG is changed to OPERABLE DG(s) in new RAs B.4.1 and B.4.2 to reflect that the RAs are to be performed for a LCO 3.8.1.d DG in addition to the OPERABLE LCO 3.8.1.b DG.

New RA B.5 is added as a prerequisite for entering the extended CT of new RA B.6 (i.e., 14 days). As specified in the TS Bases markups (Attachment 3), Emergency Supplemental Power Source (ESPS) availability requires that:

1. The load test has been performed within 30 days of entry into the extended CT.

2. The ESPS fuel tank is verified locally to be greater than or equal to a 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months supply.

3. The ESPS supporting system parameters for starting and operating are verified to be within limits for functional availability (e.g., battery state of charge).

The CT of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from discovery of unavailable ESPS of new RA B.6 (formerly RA B.4) is based on the existing CT for an inoperable DG. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT of new RA B.6 is based on Branch Technical Position 8-8 and indicates that if the ESPS unavailability occurs sometime after 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of continuous DG inoperability (i.e., after entering the extended CT for an inoperable DG), then the remaining time to restore the ESPS to available status or restore the DG to operable status is limited to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The 14 day CT of new RA B.6 is in accordance with Branch Technical Position 8-8, which indicates that operation may continue when a DG is inoperable for a period that should not exceed 14 days, provided a supplemental AC power source is available. The ESPS is the supplemental AC power source for CNS. The 17 day CT of new RA B.6 limits the total time that LCO 3.8.1.a or LCO 3.8.1.b is not met while concurrently or simultaneously in Conditions A and B. The existing CT is the sum of the CT for RA A.3 (i.e.,

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ) and existing RA B.4 (i.e., 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ). CNS is proposing to increase the CT for existing RA B.4 to 14 days; thus the maximum CT for new RA B.6 will be increased from 6 days to 17 days.

New Condition C reflects that with an opposite unit DG inoperable, the remaining operable unit-specific DG and the required offsite circuits are adequate to supply power to the onsite Class 1E Distribution System. The CT of new RAs C.1.1 and C.1.2 are in accordance with Regulatory Guide 1.93, which indicates operation may continue in this condition for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT takes into account the capacity and capability of the remaining AC power sources, a reasonable time for repairs and the low probability of a DBA occurring during the period.

New Condition D is added for an inoperable qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES. The Note above new RA D.1 indicates that when Condition D is entered with no AC source to a train, the Conditions and RAs for LCO 3.8.9, Distribution Systems - Operating, must be immediately entered. This allows new Condition D to provide requirements for the loss of a LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. LCO 3.8.9 provides the appropriate restrictions for a de-energized train.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 19 New RA D.1 ensures a highly reliable power source remains with the one necessary LCO 3.8.1.c offsite circuit (necessary only when the offsite circuit is aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of the NSWS, CRAVS, CRACWS and ABFVES) inoperable by verifying the operability of the remaining required offsite circuits. The CT for new RA D.1 is consistent with NUREG-1431 and the CT for existing RA A.1.

New RA D.2 only applies if the train cannot be powered from an offsite source and is intended to provide assurance that an event coincident with a single failure of the associated DG will not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES.

The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT for new RA D.2 is considered acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

The remaining operable offsite circuits and DGs are adequate in this condition to supply power to the Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT also takes into account the component operability of the redundant counterpart to the inoperable NSWS, CRAVS, CRACWS or ABFVES, the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

New RA D.3 reflects that if the inoperable qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES cannot be restored to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , then the NSWS, CRAVS, CRACWS and ABFVES components associated with the inoperable offsite circuit must be declared inoperable. The ACTIONS associated with the LCOs for those shared systems will ensure that appropriate action is taken. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT for new RA D.3 takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

New Condition E is added for an opposite unit DG necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES inoperable. The Note above new RA E.1 indicates that when Condition E is entered with no AC source to a train, the Conditions and RAs for LCO 3.8.9, Distribution Systems - Operating, must be immediately entered. This allows new Condition E to provide requirements for the loss of a LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. LCO 3.8.9 provides the appropriate restrictions for a de-energized train.

The new RA E.1 to verify both unit-specific DGs are operable, the other opposite units DG is operable and the ESPS is available forms the basis for the 14 day CT of new RA E.5. The verification in this RA provides assurance that the other three safety-related DGs and the ESPS are capable of supplying the Class 1E AC Electrical Power Distribution System.

New RA E.2 ensures a highly reliable power source remains with the one necessary LCO 3.8.1.d DG (necessary only when the DG is aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of the NSWS, CRAVS, CRACWS and ABFVES) inoperable by verifying the operability of the remaining required offsite circuits. The CT for new RA E.2 is consistent with NUREG-1431 and the CT for existing RA A.1.

New RA E.3 is intended to provide assurance that a loss of offsite power, during the period a LCO 3.8.1.d DG is inoperable, does not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES. Four hours (i.e., the CT for new RA E.3) from discovering the LCO 3.8.1.d DG inoperable coincident with one train of NSWS, CRAVS, CRACWS or ABFVES inoperable that is associated with the other train that has emergency

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 20 power is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown. The four hour CT also takes into account the capacity and capability of the remaining NSWS, CRAVS, CRACWS and ABFVES train, a realistic time for repairs and the low probability of a DBA occurring during this period.

The remaining operable DGs and offsite circuits are adequate in this condition to supply electrical power to the onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the NSWS, CRAVS, CRACWS or ABFVES may have been lost; however, function has not been lost.

New RA E.4.1 provides an allowance to avoid unnecessary testing of operable DGs. If it can be determined that the cause of the inoperable LCO 3.8.1.d DG (opposite unit DG necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES) does not exist on the operable DGs, then SR 3.8.1.2 does not have to be performed. In accordance with new RA E.4.2, if the cause of the initial inoperable LCO 3.8.1.d DG cannot be confirmed not to exist on the remaining DGs, then performance of SR 3.8.1.2 suffices to provide assurance of continued operability of the DGs. According to Generic Letter 84-15, Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT is reasonable to confirm that the operable DGs are not affected by the same problem as the inoperable LCO 3.8.1.d DG.

New RA E.5 reflects that if the opposite unit DG that is needed to supply power to the NSWS, CRAVS, CRACWS and ABFVES cannot be restored to operable status within 14 days, then the NSWS, CRAVS, CRACWS and ABFVES components associated with the inoperable DG must be declared inoperable. The Actions associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure the appropriate actions are taken. The CT of 14 days is justified by new RA E.1 (verify both unit-specific DGs are operable, the other opposite unit DG is operable and the ESPS is available). The 14 day CT is also consistent with the proposed CT in ACTION B when ESPS is available.

New Condition F is added to indicate that with an additional safety-related DG inoperable or the ESPS unavailable, the remaining operable DG and qualified circuits are adequate to supply electrical power to the onsite Class 1E Distribution System.

New RA F.1.1 is provided to restore both of the unit-specific DGs to operable, the other opposite unit DG to operable and the ESPS to available. New RA F.1.2 is provided to restore the LCO 3.8.1.d DG to operable. Either of the new RAs F.1.1 and F.1.2 must be completed within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT for RAs F.1.1 and F.1.2 is consistent with Regulatory Guide 1.93, Availability of Electric Power Sources. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT also takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during the period.

New RA F.1.3 reflects that if the opposite unit DG that is necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES cannot be restored to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , then the NSWS, CRAVS, CRACWS and ABFVES components associated with the inoperable DG must be declared inoperable. The ACTIONS associated with the LCOs for those shared systems will ensure that appropriate action is taken. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT for new RA F.1.3 takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

Renaming Condition C to Condition G is an administrative change. Adding LCO 3.8.1.a to new Condition G clarifies that the portion of the Condition pertains to the qualified circuits between the offsite transmission network and the Onsite Essential Auxiliary Power System

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 21 rather than a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System. The second part of Condition G after the OR connector is added to reflect when the offsite circuit required by LCO 3.8.1.c and one offsite circuit required by LCO 3.8.1.a are concurrently inoperable, if the LCO 3.8.1.a offsite circuit is credited with providing power to the NSWS, CRAVS, CRACWS and ABFVES.

Renaming RAs C.1 and C.2 to G.1 and G.2 is an administrative change. Changing Condition C to Condition G in the CT for new RA G.1 is an administrative change.

Renaming Condition D to Condition H is an administrative change. Adding LCO 3.8.1.a and LCO 3.8.1.b to new Condition H clarifies that the Condition pertains to a qualified circuit between the offsite transmission network and the Onsite Essential Auxiliary Power System (rather than a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System) and to a DG capable of supplying the Onsite Essential Auxiliary Power Systems (rather than a DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES).

Changing Condition D to Condition H in the NOTE above new RA H.1 is an administrative change. Renaming RAs D.1 and D.2 to H.1. and H.2 is an administrative change.

Renaming Condition E to Condition I is administrative change. Adding LCO 3.8.1.b to new Condition I clarifies that this portion of the Condition pertains to the unit-specific DGs rather than a DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES. The second part of Condition I after the OR connector is added to reflect that with one LCO 3.8.1.d DG inoperable and the LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable, there are no remaining standby AC sources to the shared portions of the NSWS, CRAVS, CRACWS and ABFVES.

Renaming RA E.1 to I.1 is an administrative change.

Renaming Condition F to Condition J is an administrative change. Renaming RA F.1 to J.1 is an administrative change.

Renaming Condition G to Condition K is an administrative change. All of the proposed revisions to new Condition K reflect instances where the RA and associated CT of a Condition (or RA) are not met.

Renaming RAs G.1 and G.2 to K.1 and K.2 is an administrative change.

Renaming Condition H to Condition L is an administrative change. Adding LCO 3.8.1.a and LCO 3.8.1.b to new Condition L clarifies that the Condition corresponds to a level of degradation in which all redundancy in the unit-specific (i.e., LCO 3.8.1.a and LCO 3.8.1.b) AC electrical power supplies has been lost.

The new NOTE added to the SURVEILLANCE REQUIREMENTS section of CNS TS 3.8.1 clarifies that not all of the SRs are applicable to all the components described in the LCO.

New SR 3.8.1.21 lists the SRs that are applicable to new LCO 3.8.1.c and new LCO 3.8.1.d.

These SRs are 3.8.1.1, 3.8.1.2, 3.8.1.4, 3.8.1.5 and 3.8.1.6. The Frequency of new SR 3.8.1.21 is to be in accordance with the CNS Surveillance Frequency Control Program.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 22 2.2 McGuire Evaluation of the TS 3.8.1 Change Request In order to continue to meet Criterion 3 of 10 CFR 50.36 with the removal of the requirement from the MNS TS Bases to maintain both normal and emergency power for operability of the shared systems (NSWS, CRAVS, CRACWS and ABFVES), the opposite units AC power sources that are necessary to support the NSWS, CRAVS, CRACWS and ABFVES are incorporated into TS 3.8.1 within new LCOs 3.8.1.c and 3.8.1.d. Each train of NSWS, CRAVS, CRACWS and ABFVES is connected to an onsite Class 1E electrical power distribution subsystem from either unit. The word necessary used in LCO 3.8.1.c and LCO 3.8.1.d clarifies that the respective AC power source is aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of shared systems. For example, in a normal alignment at MNS, Unit 1 Essential Bus 1ETA supplies Train A of shared systems and Unit 2 Essential Bus 2ETB supplies Train B of shared systems. Thus for this normal plant configuration, the 2B offsite circuit and 2B DG, both of which supply power to 2ETB, would be LCO 3.8.1.c and LCO 3.8.1.d AC sources for Unit 1 TS 3.8.1. Similarly, the 1A offsite circuit and 1A DG, both of which supply power to 1ETA, would be LCO 3.8.1.c and LCO 3.8.1.d AC sources for Unit 2 TS 3.8.1. However, since the 2A offsite circuit and 2A DG are not necessary to supply power to a train of shared systems in the normal plant configuration, they would not be LCO 3.8.1.c and LCO 3.8.1.d AC sources. And since the 1B offsite circuit and 1B DG are not necessary to supply power to a train of shared systems in the normal plant configuration, they would not be LCO 3.8.1.c and LCO 3.8.1.d AC sources. It is important to note that if desired or required to maintain operability, Train A shared equipment can be swapped to receive power from Unit 2 Essential Bus 2ETA. Similarly, Train B shared equipment can be swapped to receive power from Unit 1 Essential Bus 1ETB.

The Note that is added to the Applicability section takes exception to the requirements for the required AC sources in LCO 3.8.1.c and LCO 3.8.1.d provided the associated shared systems are inoperable. This exception is intended to allow declaring the shared systems supported by the opposite unit inoperable either in lieu of declaring the LCO 3.8.1.c and LCO 3.8.1.d AC sources inoperable, or at any time subsequent to entering ACTIONS for an inoperable LCO 3.8.1.c or LCO 3.8.1.d AC source. This exception is acceptable since, with the shared systems supported by the opposite unit inoperable and the associated ACTIONS entered, the LCO 3.8.1.c and LCO 3.8.1.d AC sources provide no additional assurance that acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of abnormal transients and also provide no additional assurance that adequate core cooling is provided and containment operability and other vital functions are maintained in the event of a postulated design basis accident (DBA).

Adding LCO 3.8.1.a to Condition A clarifies that the Condition pertains to a qualified circuit between the offsite transmission network and the Onsite Essential Auxiliary Power System rather than a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System.

Changing OPERABLE offsite circuit to required OPERABLE offsite circuit(s) in RA A.1 reflects that it could be necessary to verify the operability of more than one offsite circuit when a LCO 3.8.1.a offsite circuit is inoperable, since an offsite circuit may be aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of the NSWS, CRAVS, CRACWS and ABFVES (i.e., a LCO 3.8.1.c offsite circuit).

The proposed maximum CT of 17 days for RA A.3 limits the total time that LCO 3.8.1.a or LCO 3.8.1.b is not met while concurrently or simultaneously in Conditions A and B. The existing CT

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 23 is the sum of the CT for RA A.3 (i.e., 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ) and existing RA B.4 (i.e., 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ). MNS is proposing to increase the CT for existing RA B.4 to 14 days; thus the maximum CT for RA A.3 will be increased from 6 days to 17 days.

Adding LCO 3.8.1.b to Condition B clarifies that the Condition pertains to a unit-specific DG rather than a DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES.

New RA B.1 provides assurance that the LCO 3.8.1.d DG is operable when a LCO 3.8.1.b DG is inoperable.

Renaming RAs B.1, B.2, B.3.1, B.3.2 and B.4 are administrative changes.

OPERABLE DG is changed to OPERABLE DG(s) in new RAs B.4.1 and B.4.2 to reflect that the RAs are to be performed for a LCO 3.8.1.d DG in addition to the OPERABLE LCO 3.8.1.b DG.

New RA B.5 is added as a prerequisite for entering the extended CT of new RA B.6 (i.e., 14 days). As specified in the TS Bases markups (Attachment 3), Emergency Supplemental Power Source (ESPS) availability requires that:

1. The load test has been performed within 30 days of entry into the extended CT.

2. The ESPS fuel tank is verified locally to be greater than or equal to a 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months supply.

3. The ESPS supporting system parameters for starting and operating are verified to be within limits for functional availability (e.g., battery state of charge).

The CT of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from discovery of unavailable ESPS of new RA B.6 (formerly RA B.4) is based on the existing CT for an inoperable DG. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT of new RA B.6 is based on Branch Technical Position 8-8 and indicates that if the ESPS unavailability occurs sometime after 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of continuous DG inoperability (i.e., after entering the extended CT for an inoperable DG), then the remaining time to restore the ESPS to available status or restore the DG to operable status is limited to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The 14 day CT of new RA B.6 is in accordance with Branch Technical Position 8-8, which indicates that operation may continue when a DG is inoperable for a period that should not exceed 14 days, provided a supplemental AC power source is available. The ESPS is the supplemental AC power source for MNS. The 17 day CT of new RA B.6 limits the total time that LCO 3.8.1.a or LCO 3.8.1.b is not met while concurrently or simultaneously in Conditions A and B. The existing CT is the sum of the CT for RA A.3 (i.e.,

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ) and existing RA B.4 (i.e., 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ). MNS is proposing to increase the CT for existing RA B.4 to 14 days; thus the maximum CT for new RA B.6 will be increased from 6 days to 17 days.

New Condition C reflects that with a LCO 3.8.1.d DG inoperable, the remaining operable unit-specific DG and the required offsite circuits are adequate to supply power to the onsite Class 1E Distribution System. The CT of new RAs C.1.1 and C.1.2 are in accordance with Regulatory Guide 1.93, which indicates operation may continue in this condition for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT takes into account the capacity and capability of the remaining AC power sources, a reasonable time for repairs and the low probability of a DBA occurring during the period.

New Condition D is added for an inoperable qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 24 power to the NSWS, CRAVS, CRACWS and ABFVES. The Note above new RA D.1 indicates that when Condition D is entered with no AC source to a train, the Conditions and RAs for LCO 3.8.9, Distribution Systems - Operating, must be immediately entered. This allows new Condition D to provide requirements for the loss of a LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. LCO 3.8.9 provides the appropriate restrictions for a de-energized train.

New RA D.1 ensures a highly reliable power source remains with the one necessary LCO 3.8.1.c offsite circuit (necessary only when the offsite circuit is aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of the NSWS, CRAVS, CRACWS and ABFVES) inoperable by verifying the operability of the remaining required offsite circuits. The CT for new RA D.1 is consistent with NUREG-1431 and the CT for existing RA A.1.

New RA D.2 only applies if the train cannot be powered from an offsite source and is intended to provide assurance that an event coincident with a single failure of the associated DG will not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES.

The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT for new RA D.2 is considered acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

The remaining operable offsite circuits and DGs are adequate in this condition to supply power to the Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT also takes into account the component operability of the redundant counterpart to the inoperable NSWS, CRAVS, CRACWS or ABFVES, the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

New RA D.3 reflects that if the inoperable qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES cannot be restored to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , then the NSWS, CRAVS, CRACWS and ABFVES components associated with the inoperable offsite circuit must be declared inoperable. The ACTIONS associated with the LCOs for those shared systems will ensure that appropriate action is taken. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT for new RA D.3 takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

New Condition E is added for an opposite unit DG necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES inoperable. The Note above new RA E.1 indicates that when Condition E is entered with no AC source to a train, the Conditions and RAs for LCO 3.8.9, Distribution Systems - Operating, must be immediately entered. This allows new Condition E to provide requirements for the loss of a LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. LCO 3.8.9 provides the appropriate restrictions for a de-energized train.

The new RA E.1 to verify both unit-specific DGs are operable and the ESPS is available forms the basis for the 14 day CT of new RA E.5. The verification in this RA provides assurance that the LCO 3.8.1.b safety-related DGs and the ESPS are capable of supplying the Class 1E AC Electrical Power Distribution System.

New RA E.2 ensures a highly reliable power source remains with the one necessary LCO 3.8.1.d DG (necessary only when the DG is aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of the NSWS, CRAVS, CRACWS and

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 25 ABFVES) inoperable by verifying the operability of the remaining required offsite circuits. The CT for new RA E.2 is consistent with NUREG-1431 and the CT for existing RA A.1.

New RA E.3 is intended to provide assurance that a loss of offsite power, during the period a LCO 3.8.1.d DG is inoperable, does not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES. Four hours (i.e., the CT for new RA E.3) from discovering the LCO 3.8.1.d DG inoperable coincident with one train of NSWS, CRAVS, CRACWS or ABFVES inoperable that is associated with the other train that has emergency power is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown. The four hour CT also takes into account the capacity and capability of the remaining NSWS, CRAVS, CRACWS and ABFVES train, a realistic time for repairs and the low probability of a DBA occurring during this period.

The remaining operable DGs and offsite circuits are adequate in this condition to supply electrical power to the onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the NSWS, CRAVS, CRACWS or ABFVES may have been lost; however, function has not been lost.

New RA E.4.1 provides an allowance to avoid unnecessary testing of operable DGs. If it can be determined that the cause of the inoperable LCO 3.8.1.d DG (opposite unit DG necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES) does not exist on the operable DGs, then SR 3.8.1.2 does not have to be performed. In accordance with new RA E.4.2, if the cause of the initial inoperable LCO 3.8.1.d DG cannot be confirmed not to exist on the remaining DGs, then performance of SR 3.8.1.2 suffices to provide assurance of continued operability of the DGs. According to Generic Letter 84-15, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months CT is reasonable to confirm that the operable DGs are not affected by the same problem as the inoperable LCO 3.8.1.d DG.

New RA E.5 reflects that if the opposite unit DG that is needed to supply power to the NSWS, CRAVS, CRACWS and ABFVES cannot be restored to operable status within 14 days, then the NSWS, CRAVS, CRACWS and ABFVES components associated with the inoperable DG must be declared inoperable. The Actions associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure the appropriate actions are taken. The CT of 14 days is justified by new RA E.1 (verify both unit-specific DGs are operable and the ESPS is available). The 14 day CT is also consistent with the proposed CT in ACTION B when ESPS is available.

New Condition F is added to indicate that with an additional LCO 3.8.1.b safety-related DG inoperable or the ESPS unavailable, the remaining operable LCO 3.8.1.b DG and qualified circuits are adequate to supply electrical power to the onsite Class 1E Distribution System.

New RA F.1.1 is provided to restore both of the unit-specific DGs to operable and the ESPS to available. New RA F.1.2 is provided to restore the LCO 3.8.1.d DG to operable. Either of the new RAs F.1.1 and F.1.2 must be completed within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT for RAs F.1.1 and F.1.2 is consistent with Regulatory Guide 1.93. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT also takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during the period.

New RA F.1.3 reflects that if the opposite unit DG that is necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES cannot be restored to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , then the NSWS, CRAVS, CRACWS and ABFVES components associated with the inoperable DG must be declared inoperable. The ACTIONS associated with the LCOs for those shared systems will ensure that appropriate action is taken. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CT for new RA F.1.3 takes

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 26 into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

Renaming Condition C to Condition G is an administrative change. Adding LCO 3.8.1.a to new Condition G clarifies that the portion of the Condition pertains to the qualified circuits between the offsite transmission network and the Onsite Essential Auxiliary Power System rather than a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System. The second part of Condition G after the OR connector is added to reflect when the offsite circuit required by LCO 3.8.1.c and one offsite circuit required by LCO 3.8.1.a are concurrently inoperable, if the LCO 3.8.1.a offsite circuit is credited with providing power to the NSWS, CRAVS, CRACWS and ABFVES.

Renaming RAs C.1 and C.2 to G.1 and G.2 is an administrative change. Changing Condition C to Condition G in the CT for new RA G.1 is an administrative change.

Renaming Condition D to Condition H is an administrative change. Adding LCO 3.8.1.a and LCO 3.8.1.b to new Condition H clarifies that the Condition pertains to a qualified circuit between the offsite transmission network and the Onsite Essential Auxiliary Power System (rather than a qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System) and to a DG capable of supplying the Onsite Essential Auxiliary Power Systems (rather than a DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES).

Changing Condition D to Condition H in the NOTE above new RA H.1 is an administrative change. Renaming RAs D.1 and D.2 to H.1. and H.2 is an administrative change.

Renaming Condition E to Condition I is administrative change. Adding LCO 3.8.1.b to new Condition I clarifies that the portion of the Condition pertains to the unit-specific DGs rather than a DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES. The second part of Condition I after the OR connector is added to reflect that with one LCO 3.8.1.d DG inoperable and the LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable, there are no remaining standby AC sources to the NSWS, CRAVS, CRACWS and ABFVES.

Renaming RA E.1 to I.1 is an administrative change.

Renaming Condition F to Condition J is an administrative change. Renaming RA F.1 to J.1 is an administrative change.

Renaming Condition G to Condition K is an administrative change. All of the proposed revisions to new Condition K reflect instances where the RA and associated CT of a Condition (or RA) are not met.

Renaming RAs G.1 and G.2 to K.1 and K.2 is an administrative change.

Renaming Condition H to Condition L is an administrative change. Adding LCO 3.8.1.a and LCO 3.8.1.b to new Condition L clarifies that the Condition corresponds to a level of degradation in which all redundancy in the unit-specific (i.e., LCO 3.8.1.a and LCO 3.8.1.b) AC electrical power supplies has been lost.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 27 The new NOTE added to the SURVEILLANCE REQUIREMENTS section of MNS TS 3.8.1 clarifies that not all of the SRs are applicable to all the components described in the LCO.

New SR 3.8.1.21 lists the SRs that are applicable to new LCO 3.8.1.c and new LCO 3.8.1.d.

These SRs are 3.8.1.1, 3.8.1.2, 3.8.1.4, 3.8.1.5 and 3.8.1.6. The Frequency of new SR 3.8.1.21 is to be in accordance with the MNS Surveillance Frequency Control Program.

3. ADDITIONAL TECHNICAL JUSTIFICATION FOR CATAWBA PROPOSED CHANGE Based on the September 20, 2017 public meeting for the subject LAR, Duke Energy is also providing in the following sections additional discussion regarding the CNS NSWS design basis and a clarification of statements pertaining to the NSWS that are located in Chapter 9 of the CNS UFSAR.

3.1 Discussion of NSWS Design Basis There are six NSWS headers at Catawba: Essential 1A, Unit 1 Nonessential, Essential 1B, Essential 2A, Unit 2 Nonessential and Essential 2B. There are four NSWS trains, corresponding to the four essential headers. There are two essential NSWS loops at Catawba:

A and B, each consisting of a Unit 1 and a Unit 2 essential train. The term channel is used interchangeably with loop. To understand NSWS operation, the NSWS layout must be understood. Each essential NSWS loop has a single supply line and a single return line that serves both units. This effectively makes components in the NSWS Pumphouse not unit related.

The only characteristic that ties a NSWS pump to a particular unit is the Class 1E electrical bus from which the pump receives power.

The common A and B NSWS supply lines and the crossovers between units allows flow from any NSWS pump to be directed to any NSWS header. This gives the station flexibility in normal NSWS operation, but also makes possible system faults that affect the operability of both units (discussed further in Table 1 below).

The NSWS design basis specifies that the system should be operated in a manner such that it can perform its safety function in mitigating the consequences of a design basis event accounting for a single failure in the system. The worst single failure can eliminate one loop of NSWS pumps. With that design basis concept in mind and the NSWS flow balanced to one-pump analysis values, the following statements are relevant regarding the NSWS at Catawba:

1. Four NSWS pumps are needed to operate both units without entering a Technical Specification Action statement.

2. Two operating NSWS pumps are required to mitigate the consequences of a design basis event if both units are operating. In other words, two NSWS pumps have sufficient capacity to supply post-LOCA loads on one unit and shutdown and cooldown loads on the other unit.

3. One pump is required to mitigate the consequences of a design basis event if one unit is operating and the other unit is in Mode 5 or 6. Specifically, one NSWS pump has

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 28 sufficient capacity to maintain a unit indefinitely in Cold Shutdown (commencing 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months following a trip from full power) while supplying the post-LOCA loads on the other unit.

Nuclear service water capacity capabilities are as follows:

1. One operating NSWS pump can supply one essential loop in the one-pump analysis mode.

2. Two operating NSWS pumps can supply one essential loop (two essential headers) and both nonessential headers, or two NSWS pumps can supply the total flow demands of one unit with limited flow to the other unit. Note that the NSWS Single Supply Header Operation (SSHO) Evaluation calculation was performed to verify the NSWS Single Supply Header alignment and demonstrated that while the NSWS is aligned in SSHO, two NSWS pumps have adequate capacity to supply all four NSWS essential headers and all four diesel generators, assuming a design-basis event on one unit, a LOOP on both units, a loss of Lake Wylie resulting in isolation of both NSWS non-essential headers, and one NSWS pump pit suction transfer failure resulting in the loss of two NSWS pumps.

3. Three operating NSWS pumps can supply flow to all six NSWS headers.

The scenarios below in Table 1 represent the possible combinations of events and failures in the Catawba NSWS for the proposed change. Not all possible combinations are described, but the combinations that are presented bound other possible combinations (i.e., failure of valve 1RN3A is presented, which bounds the corresponding opposite train failure of valve 1RN4B).

Two figures (simplified diagrams) are provided following Table 1 for each Case Number provided in Table 1. The first diagram for each Case Number represents the NSWS alignment with the initial conditions and the second diagram represents the NSWS alignment post event.

To understand the NSWS response to the various scenarios and failures presented in Table 1, the single failure considerations for the NSWS system must be explained. Per the Design Basis Specification for the NSWS, single failure considerations regarding the NSWS are as follows:

x If both units are operable, the NSWS shall be capable of mitigating the consequences of a design basis event on one unit, concurrent with a Loss of Offsite Power affecting both units, assuming a single failure on the system. (Two failures, i.e., one per unit, is not assumed.) The design basis event may be assumed concurrent with worse case conditions (e.g., Loss of Lake Wylie).

x If one unit is in an action statement and the other unit is operable, the NSWS shall be capable of mitigating the consequences of a design basis event on the operating unit, concurrent with a Loss of Offsite Power assuming a single failure of any unit related component required to support operation of the operable unit. Failures of shared system components are not postulated. The diesel generators are shared components with regard to their supporting function of NSWS. A single failure is not postulated on the unit in an action statement or either of that unit's diesel generators.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 29 x If one unit is operable and the other unit is shut down, the NSWS shall be capable of mitigating the consequences of a design basis event on the operating unit, concurrent with a Loss of Offsite Power assuming a single failure of any unit related or shared component required to support operation of the operable unit.

x If both units are in action statements, single failures are not postulated on any NSWS unit related or shared component.

Please refer to the following definitions for Table 1:

ECCS - Emergency Core Cooling Systems EDG - Emergency Diesel Generator ESPS - Emergency Supplemental Power Source HX - Heat Exchanger LOCA - Loss of Coolant Accident LOOP - Loss of Offsite Power SNSWP - Standby Nuclear Service Water Pond Sp - High High Pressure Signal in Containment

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 30 Table 1 - NSWS Scenarios and System Response Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands (1) Unit 1 LOCA (Sp) No failures The NSWS remains aligned to Lake NSWS Pump NSWS aligned to Lake LOOP Both Units Wylie. motor demands Wylie 1A, 1B, 2A, 2B Unit 1 - Mode 1 Sp = High High The Unit 1 NSWS crossover valves and Unit 2 - Mode 1 Pressure Signal non-essential header supply valves NSWS Strainer All equipment Operable in Containment close, isolating the Unit 1 NSWS Non- backwash Essential Header. 1A, 1B, 2A, 2B The Unit 2 NSWS crossover valves Component remain open, allowing NSWS flow Cooling (CC) HX between loops A and B and to the Unit 2 1A, 1B, 2A, 2B NSWS Non-Essential header. This provides non-assured NSWS backup flow Containment to non-essential components. Spray (CS) HX 1A, 1B Loop A NSWS Pumps 1A and 2A supply NSWS flow to EDGs 1A and 2A, 1A and Diesel Jacket 2A NSWS Essential Headers and cross- Water Cooling train through Unit 2 crossover valves, as HX 1A, 1B, 2A, required. 2B Loop B NSWS Pumps 1B and 2B supply Auxiliary NSWS flow to EDGs 1B and 2B, 1B and Feedwater 2B NSWS Essential Headers and cross- Makeup 1A, 1B, train through Unit 2 crossover valves, as 2A, 2B required.

CRACWS Chiller Summary - The NSWS is capable of A or B supporting the required LOCA loads on Unit 1 and Hot Standby loads on Unit 2. U2 NSWS Non-Essential Header

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 31 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands (2) Unit 1 LOCA (Sp) No failures The NSWS aligns to the Standby Nuclear NSWS Pump NSWS aligned to Lake LOOP Both Units Service Water Pond (SNSWP). motor demands Wylie Loss of Lake 1A, 1B, 2A, 2B Unit 1 - Mode 1 Wylie The NSWS loops are isolated from each Unit 2 - Mode 1 other by closure of crossover valves. NSWS Strainer All equipment Operable backwash The Loop A NSWS Pumps 1A and 2A 1A, 1B, 2A, 2B supply NSWS flow to EDGs 1A and 2A and to the 1A and 2A NSWS Essential CC HX 1A, 1B, Headers. 2A, 2B The Loop B NSWS Pumps 1B and 2B CS HX 1A, 1B supply NSWS flow to EDGs 1B and 2B and to the 1B and 2B NSWS Essential Diesel Jacket Headers. Water Cooling HX 1A, 1B, 2A, The Unit 1 and 2 NSWS Non-Essential 2B Headers are isolated due to closure of crossover valves during swap to the Auxiliary SNSWP. Feedwater Makeup 1A, 1B, Summary - The NSWS is capable of 2A, 2B supporting the required LOCA loads on Unit 1 and Hot Standby loads on Unit 2. CRACWS Chiller A or B (3) Unit 1 LOCA (Sp) No Failures The NSWS remains aligned to the NSWS Pump NSWS aligned to the LOOP Both Units SNSWP. motor demands SNSWP 1A, 1B, 2A, 2B Unit 1 - Mode 1 The Unit 1 NSWS crossover valves and Unit 2 - Mode 1 non-essential header supply valves NSWS Strainer All equipment Operable close, isolating the Unit 1 NSWS Non- backwash Essential Header. 1A, 1B, 2A, 2B

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 32 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands The Unit 2 NSWS crossover valves CC HX 1A, 1B, remain open, allowing NSWS flow 2A, 2B between loops A and B and to the Unit 2 NSWS Non-Essential header. This CS HX 1A, 1B provides non-assured NSWS backup flow to Unit 2 non-essential components. Diesel Jacket Water Cooling The Loop A NSWS Pumps 1A and 2A HX 1A, 1B, 2A, supply NSWS flow to EDGs 1A and 2A, 2B 1A and 2A NSWS Essential Headers and cross-train through the Unit 2 crossover Auxiliary valves, as required. Feedwater Makeup 1A, 1B, The Loop B NSWS Pumps 1B and 2B 2A, 2B supply NSWS flow to EDGs 1B and 2B, the 1B and 2B NSWS Essential Headers CRACWS Chiller and cross-train through the Unit 2 A or B crossover valves, as required.

Unit 2 NSWS Summary - The NSWS is capable of Non-Essential supporting the required LOCA loads on Header Unit 1 and Hot Standby loads on Unit 2.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 33 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands (4) Unit 1 LOCA (Sp) EDG 1A Fails, resulting in The NSWS remains aligned to the NSWS Pump NSWS Aligned to the LOOP Both Units 1A NSWS pump failure and SNSWP. motor demands SNSWP 1A ECCS failure 1B, 2A, 2B Unit 1 - Mode 1 The Unit 1 NSWS crossover valve Unit 2 - Mode 1 1RN48B and NSWS Non-Essential NSWS Strainer All Equipment Operable header supply valves close, isolating the backwash Unit 1 NSWS Non-Essential Header. 1B, 2A, 2B The Unit 2 NSWS crossover valves CC HX 1A, 1B, remain open, allowing NSWS flow 2A, 2B between loops A and B and to the Unit 2 NSWS Non-Essential header. This CS HX 1B provides non-assured NSWS backup flow to Unit 2 non-essential components. Diesel Jacket Water Cooling The Loop A NSWS Pump 2A supplies HX 1B, 2A, 2B NSWS flow to EDG 2A, the 1A and 2A NSWS Essential Headers and cross-train Auxiliary through the Unit 2 crossover valves, as Feedwater required. Makeup 1B, 2A, 2B The Loop B NSWS Pumps 1B and 2B supply NSWS flow to EDGs 1B and 2B, CRACWS Chiller the 1B and 2B NSWS Essential Headers B and cross-train through the Unit 2 crossover valves, as required. Unit 2 NSWS Non-Essential CC HX 1A receives NSWS flow since the Header flow control valve fails open. However, CC Train 1A is not powered or available.

Summary - The NSWS is capable of supporting the required LOCA loads on

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 34 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands Unit 1 and Hot Standby loads on Unit 2.

(5) Unit 1 LOCA (Sp) Valve 1RN3A fails to open, The NSWS aligns to the SNSWP. NSWS Pump NSWS aligned to Lake LOOP Both Units resulting in loss of Pit A, motor demands Wylie Loss of Lake failure of 1A and 2A NSWS Since there are not any TS entries on 1B, 2B Unit 1 - Mode 1 Wylie Pumps, 1A and 2A EDGs, Unit 1 or Unit 2, a failure of the shared A Unit 2 - Mode 1 1A and 2A ECCS Train NSWS suction pit valve 1RN3A is NSWS Strainer All equipment Operable postulated. backwash 1B, 2B The NSWS essential loops are isolated from each other by closure of the CC HX 1B, 2B crossover valves. This isolates the failed A loop from the B loop. CS HX 1B No power is available to A Train essential Diesel Jacket equipment due to loss of the A train Water Cooling EDGs. HX 1B, 2B The Loop B NSWS Pumps 1B and 2B Auxiliary supply NSWS flow to EDGs 1B and 2B Feedwater and the 1B and 2B NSWS Essential Makeup 1B, 2B Headers.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 35 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands The Unit 1 and 2 NSWS Non-Essential CRACWS Chiller Headers are isolated due to closure of B valves during swap to the SNSWP.

Summary - The NSWS is capable of supporting the required LOCA loads on Unit 1 and Hot Standby loads on Unit 2.

(6) LOOP Both Units EDG 1A Fails, resulting in NOTE - This event assumes a failure NSWS Pump NSWS aligned to Lake 1A NSWS Pump failure (EDG 1A) while a shared component motor demands Wylie (EDG 2B) is inoperable. 1B, 2A Unit 1 - Mode 1 Unit 2 - Mode 1 The NSWS remains aligned to Lake NSWS Strainer EDG 2B is inoperable, Wylie. backwash resulting in isolation of 1B, 2A the Unit 2 Non-Essential A single failure can occur on a Unit 1 Header and closure of component since a Unit 2 component is CC HX 1A, 1B, the crossover valve inoperable. No failures are postulated on 2A, 2B NSWS Pump 2B is shared components.

operable Diesel Jacket The NSWS Pump 2B is not credited, Water Cooling since offsite power is lost and ESPS HX 1B, 2A power is not immediately available.

Auxiliary The Unit 1 NSWS crossover valves Feedwater remain open, allowing NSWS flow Makeup 1B, 2A between loops A and B and to the Unit 1 NSWS Non-Essential header. This CRACWS Chiller provides non-assured NSWS backup flow B to Unit 1 non-essential components.

Unit 1 NSWS Each NSWS Loop has one NSWS Pump Non-Essential (1B, 2A) to supply NSWS flow to EDGs Header

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 36 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands 1B and 2A, the 1B and 2A NSWS Essential Headers and the Unit 1 Non-Essential Header.

Since EDG 2B is inoperable, valves 2RN48B and 2RN50B are closed.

CC HXs 1A and 2B receive NSWS flow since the flow control valve fails open.

However, CC Trains 1A and 2B are not powered or available.

Summary - The NSWS is capable of supporting the required Hot Standby loads on Units 1 and 2.

(7) Unit 1 LOCA (Sp) EDG 1A Fails, resulting in NOTE - This event assumes a failure NSWS Pump NSWS aligned to Lake LOOP Both Units 1A NSWS Pump failure and (EDG 1A) while a shared component motor demands Wylie 1A ECCS failure (EDG 2B) is inoperable. 1B, 2A Unit 1 - Mode 1 Unit 2 - Mode 1 The NSWS remains aligned to Lake NSWS Strainer EDG 2B is inoperable, Wylie. backwash resulting in isolation of 1B, 2A the Unit 2 Non-Essential A single failure can occur on a Unit 1 Header and closure of component since a Unit 2 component is CC HX 1A, 1B, the crossover valve inoperable. No failures are postulated on 2A, 2B NSWS Pump 2B is shared components.

operable CS HX 1B The NSWS Pump 2B is not credited, since offsite power is lost and ESPS Diesel Jacket power is not immediately available. Water Cooling HX 1B, 2A Each NSWS Loop has one NSWS Pump (1B, 2A) to supply NSWS flow to EDGs Auxiliary

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 37 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands 1B and 2A, the 1B and 2A NSWS Feedwater Essential Headers. Makeup 1B, 2A Since EDG 2B is inoperable, valves CRACWS Chiller 2RN48B and 2RN50B are closed. B CC HXs 1A and 2B receive NSWS flow since the flow control valve fails open.

However, CC Trains 1A and 2B are not powered or available.

The Unit 1 and Unit 2 NSWS Non-Essential Headers are isolated.

Summary - The NSWS is capable of supporting the required LOCA loads on Unit 1 and Hot Standby loads on Unit 2.

(8) Unit 1 LOCA (Sp) EDG 1B Fails, resulting in NOTE - This event assumes a failure NSWS Pump NSWS aligned to Lake LOOP Both Units 1B NSWS Pump failure and (EDG 1B) while a shared component motor demands Wylie 1B ECCS failure (EDG 2B) is inoperable. 1A, 2A Unit 1 - Mode 1 Unit 2 - Shutdown The NSWS remains aligned to Lake NSWS Strainer EDG 2B is inoperable, Wylie. backwash resulting in isolation of 1A, 2A the Unit 2 Non-Essential A single failure can occur on EDG 1B Header and closure of since a Unit 2 component is inoperable. CC HX 1A, 2A the crossover valve No failures are postulated on shared NSWS Pump 2B is components. CS HX 1A operable The NSWS Pump 2B is not credited, Diesel Jacket since offsite power is lost and ESPS Water Cooling power is not immediately available. HX 1A, 2A

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 38 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands There are no operable NSWS pumps or Auxiliary EDGs on Loop B. Feedwater Makeup 1A Since EDG 2B is inoperable, valves 2RN48B and 2RN50B are closed. CRACWS Chiller A

Only 1A Auxiliary Feedwater Makeup.

The Unit 1 and Unit 2 NSWS Non-Essential Headers are isolated.

Summary - The NSWS is capable of supporting the required LOCA loads on Unit 1 and Shutdown loads on Unit 2.

(9) Unit 1 LOCA (Sp) EDG 1A Fails, resulting in NOTE - This event assumes a failure NSWS Pump NSWS aligned to Lake LOOP Both Units failure of valve 1RN3A to (EDG 1A) while a shared component motor demands Wylie Loss of Lake open. This results in loss of (EDG 2B) is inoperable. 1B Unit 1 - Mode 1 Wylie Pit A, failure of 1A and 2A Unit 2 - Mode 1 NSWS Pumps, 1A and 2A The NSWS aligns to the SNSWP. NSWS Strainer EDG 2B is inoperable, EDG, 1A and 2A ECCS backwash resulting in isolation of The NSWS Pump 2B is not credited, 1B the Unit 2 Non-Essential since offsite power is lost and ESPS Header and closure of power is not immediately available. CC HX 1B, 2B the crossover valve NSWS Pump 2B is Since EDG 2B is inoperable, valves CS HX 1B operable 2RN48B and 2RN50B are closed.

Diesel Jacket No power is available to A Train essential Water Cooling equipment due to loss of A train EDGs. HX 1B NSWS Loop B has one operating NSWS Auxiliary pump (1B) to supply NSWS flow to EDG Feedwater 1B, the 1B NSWS Essential Header, and Makeup 1B

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 39 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands CC HXs 1B and 2B.

CRACWS Chiller CC HX 2B receives NSWS flow since the B flow control valve fails open. However, CC Train 2B is not powered or available.

Unit 2 has no Component Cooling until ESPS is aligned.

The Unit 1 and Unit 2 NSWS Non-Essential Headers are isolated.

Summary - The NSWS is capable of supporting the required LOCA loads on Unit 1 and Hot Standby loads on Unit 2.

Unit 2 must have ESPS aligned to power the 2B Essential Bus for this scenario.

(10) Unit 1 LOCA (Sp) EDG 1B Fails, resulting in NOTE - This event assumes a failure NSWS Pump NSWS aligned to Lake LOOP Both Units failure of valve 1RN4B to (EDG 1B) while a shared component motor demands Wylie Loss of Lake open. This results in loss of (EDG 2B) is inoperable. 1A, 2A Unit 1 - Mode 1 Wylie Pit B, failure of 1B and 2B Unit 2 - Mode 1 NSWS Pumps, 1B and 2B The NSWS aligns to the SNSWP. NSWS Strainer EDG 2B is inoperable, ECCS backwash resulting in isolation of NSWS Pump 2B is not credited, since 1A, 2A, the Unit 2 Non-Essential offsite power is lost and ESPS power is Header and closure of not immediately available. CC HX 1A, 2A the crossover valve NSWS Pump 2B is Since EDG 2B is inoperable, valves CS HX 1A operable 2RN48B and 2RN50B are closed.

Diesel Jacket The NSWS essential loops are isolated Water Cooling from each other by closure of crossover HX 1A, 2A

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 40 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands valves. This isolates NSWS cooling water to 1B and 2B EDGs and the NSWS Train Auxiliary 1B and 2B supplied essential Feedwater components. Makeup 1A, 2A No power is available to B Train essential CRACWS Chiller equipment due to loss of the B train A EDGs.

The Loop A NSWS Pumps 1A and 2A supply NSWS flow to EDGs 1A and 2A and to the 1A and 2A NSWS Essential Headers.

The Unit 1 and Unit 2 NSWS Non-Essential Headers are isolated.

Summary - The NSWS is capable of supporting the required LOCA loads on Unit 1 and Hot Standby loads on Unit 2.

(11) Unit 1 LOCA (Sp) Valve 1RN3A fails to open, The NSWS aligns to the SNSWP. NSWS Pump NSWS aligned to Lake LOOP Both Units resulting in loss of Pit A, motor demands Wylie Loss of Lake failure of 1A and 2A NSWS Since Unit 2 is shutdown, the inoperable 1B Unit 1 - Mode 1 Wylie Pumps, 1A and 2A EDGs, 2B NSWS Pump does not require TS Unit 2 - Shutdown 1A and 2A ECCS entry per TS 3.7.8. Therefore, a failure of NSWS Strainer EDG 2B is operable the shared A Train NSWS suction pit backwash NSWS Pump 2B is valve 1RN3A is postulated. 1B inoperable The NSWS essential loops are isolated CC HX 1B, 2B from each other by closure of crossover valves, but NSWS Loop A has no NSWS CS HX 1B flow.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 41 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands Diesel Jacket No power is available to A Train essential Water Cooling equipment due to loss of the A train HX 1B, 2B EDGs.

Auxiliary NSWS Loop B has one operating NSWS Feedwater pump (1B) to supply NSWS flow to EDGs Makeup 1B 1B and 2B. ECCS 2B has power from 2B EDG and cooling water from 1B NSWS CRACWS Chiller Pump. B No Auxiliary Feedwater Makeup on shutdown Unit 2.

The Unit 1 and 2 NSWS Non-Essential Headers are isolated due to closure of crossover valves during swap to the SNSWP.

Summary - This scenario models the NSWS One Pump Flow Balance. The NSWS is capable of supporting the required LOCA loads on Unit 1 and Shutdown loads on Unit 2.

(12) Unit 1 LOCA (Sp) Valve 1RN3A fails to open, NOTE - This event assumes a failure NSWS Pump NSWS aligned to Lake LOOP Both Units resulting in loss of Pit A, (1RN3A) while a shared component motor demands Wylie Loss of Lake failure of 1A and 2A NSWS (EDG 2B) is inoperable. 1B Unit 1 - Mode 1 Wylie Pumps, 1A and 2A EDGs, Unit 2 - Shutdown 1A and 2A ECCS The NSWS aligns to the SNSWP. NSWS Strainer EDG 2B is inoperable, backwash resulting in isolation of Since Unit 2 is shutdown, the inoperable 1B the Unit 2 Non-Essential 2B EDG does not require TS entry per TS

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 42 Case Number / Event Single Failure Description of NSWS Response Post Event Initial Conditions NSWS Flow Demands Header and closure of 3.8.2 (only 1 EDG is required on the CC HX 1B, 2B the crossover valve shutdown unit).

NSWS Pump 2B CS HX 1B is operable Since EDG 2B is inoperable, valves 2RN48B and 2RN50B are closed. Diesel Jacket Water Cooling No power is available to A Train essential HX 1B equipment due to loss of the A train EDGs. Auxiliary Feedwater The NSWS Loop B has one operating Makeup 1B NSWS pump (1B).

CRACWS Chiller The NSWS Pump 2B is not credited, B since offsite power is lost and ESPS power is not immediately available.

CC HX 2B receives NSWS flow since the flow control valve fails open. However, CC Train 2B is not powered or available until and unless ESPS is aligned.

No Auxiliary Feedwater Makeup on shutdown Unit 2.

The Unit 1 and Unit 2 NSWS Non-Essential Headers are isolated.

Summary - The NSWS is capable of supporting the required LOCA loads on Unit 1 and Shutdown loads on Unit 2.

However, Unit 2 must have ESPS aligned to power the 2B Essential Bus.

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 43 Figure 1a - Case Number 1 (Initial Conditions)

Case 1 - Initial Conditions Aligned t o Lake Wylie SNSW PONO OFF Unit 1 - Mode 1

~

1RN5A IRN6B I 28 DIG Unit 2 - Mode 1 OFF I I All Equipment Operable 18 0/G 28 DIG IRN848B 2RN848B IRN58B

,,OFF

" ~ msMe IRN69B SNSW PONO ~ 18 18 ESS 2B ESS 28 ESS

!RN4B HEADER HEADER HEADER OFF o-----1"JRN538 2RN47A IRN47A I I w

""<I:

_J I I UNIT 2 NON-ESS ~

HEADER 2RN50B 2RN49A !RN49A IRN50B UN IT I NON- ESS HEADER 1RN5 1A 1RN528 2RN52B 2RN5 1A U2 NON-ESS HEADER I I I 2RN4 88 1RN48B OFF 2A ESS IA ESS ~ 2A ESS

~ *I ~

SNSW PONO 2A 0/G HE ADER HE ADER HEADER I RN3A OFF I

1 1 2RN67A IRN67A

[J-:l( I RN8438 2RN846A SNSW PONO t -.1~

2A 0/ G 1 ~ IRN57A

! RNIA 1RN2B I

~

IA 0/G OFF I RN8 46A IA~ /G 28 0/G L2RN8498

~8 180/G ON I

F A!A D/G 2A D/G ___l_J 2RN84 7A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 44 Figure 1b - Case Number 1 (Event Response)

Case 1 - Event Response Unit 1 LOCA SNSW PONO 1RN5A 1RNGB I ,

~

/ I I ON 28 IJ/G LOOP_bot h Unit s No failures ON ,

i=-

18 D/G - --l,.- ~14--- 9illl-- 28 IJ/G I RN848 B 2RN8 48B

- 2RN69B IRN58B

~

18 DIG JAN69B SNSW PONO ,___,___ _ _ _ ___, ON 18 ON 28 ESS HEADER ~

18 ESS HE ADER o---1 JRN53B 2B ESS HEAD ER 2;1 w

_J

~

I II I

UNIT 2 NON-ESS HEADER 2RN50B 2RN49A 2RN 4 7A

~ ~ ~

1RN49 A 1RN50B

UN IT I NON- ESS ~

HEADER JRN5 1A I RN52B 2RN52B 2RN5 1A U2 NON-ESS HE ADER

"'" "'"' ~

IOO A

I (;:) I 2A ON

1 2AON 0/G tI

,0 ' "ER HE AD 2RN 48B 2RN67 A

+ IA ADER HE 2A 0/ G ESS _ 't'I _______J.____

I

[J-:l( 1RN843B 2AADER HE ESS 2RN84VA - l ~ I RN57 A SNSW POND -

I RN6 3 A r

I A 0/G I RN8 46A IA D/ G L ~

1B 0/G

! RNJA I RN2B I \,_

~

/ I ON 2B 0/ G 2 RN 84 9B I RN8 49B ON 2A D/ G ~

9 I F A

!A O/G 2RN8 4 7A L AKE WYLIE

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 45 Figure 2a - Case Number 2 (Initial Conditions)

Case 2 - Initial Conditions Aligned to Lake Wylie Unit 1 - Mode 1 SNSW PONO OF F Unit 2 - Mode 1

~

1RN5A IRN6B I 28 DIG All Equipment Operable OFF I I 1B D/G 28 DIG IRN848B 2RNB48B IRN58B

,,OFF

" ~ msMe IRN69B SNSW PONO ~ 18 18 ESS 2B ESS 28 ESS

!RN4B HEADER HEADER HEADER OFF o-----1"JRN53B 2RN47A IRN47A I I w

""<I:

_J I I UNI T 2 NON- ESS ~

HEAOER 2RN50B 2RN49A !RN49A IRN508 UN IT I NON- ESS HEADER 1RN5 1A 1RN528 2RN528 2RN5 1A U2 NON-ESS HEADER I I I 2RN4 8B 1RN488 OFF 2A ESS IA ESS ~ 2A ESS

~ *I ~

SNSW PONO 2A 0/G HEADER HE ADER HEADER I RN3A OFF I

1 1 2RN67A IRN67A

[J-:l( IRN84 38 2RN846A SNSW PONO t- .1~

2A 0/ G 1 ~ IRN57A

! RNIA 1RN28 I

~

IA 0/G OFF I RN8 46A IA~ /G 28 0/G L2RN849B

~B 1B0/G ON I

F!A A O/G 2A D/G _ _ l _ J 2RN84 7A LAKE WYLIE

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 46 Figure 2b - Case Number 2 (Event Response)

Case 2 - Event Response Unit 1 LOCA ~N<;w PnNn l RN5A lRNGB I \.

~

/ I ON 28 0/ G LOOP bot h Unit s Loss of Lake Wylie, RN System aligns to SNSWP ON N o fa ilurf's 18 0/G 28 DIG 1=-- """' ________. ,_ _____

1RN8488 2RN84 88 5

~ 2RN69B JRN BB

~ ~ -----=-I 1B 0/G JRN69B SNSW POND \ ~--+------.eJ ON IB 28 ESS 1B ESS 2B ESS

=oc, HEADER ON I I o-i 2RN47 A

.J I II w -

~

~ UNIT 2 NON-ESS ~ ~

UNIT l NON-ESS U2 NON-ESS HEADER HEADER H AD R 2RN508 2RN49A ' 1RN49A 1RN50B lR~A E E

"" '°~ _J,____.J l ~N;A

1

~

2A ON I *1 ON 2A DIG i

" ess HEADER 2RN48B 2RN67A

+ A I A ESS _

HEADER 2A 0/G

't'I ______J,.___

T 2 A ESS HEADER 2RN84: E 4 A SNSW PONO

1RN63A l RN846A l A .DIG JA 0/G ~ i.-w- 1B DIG l RNJA I RN2B I ci I ON 2B DI G *1 I l RN849B ON 2RN8498 2A 0/ G ~

9 l rit lA O/GA 2RN847A L AKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 47 Figure 3a - Case Number 3 (Initial Conditions)

Case 3 - Initial Conditions Aligned to SNSWP SNSW POND Unit 1 - Mode 1 I ~

lHN; A JRNG.B OFF 28 0/G o~~ I Unit 2 - Mode 1 All Equipment Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW PONO ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

~7

([

_J I I UNIT 2 NON-ESS ~

HEADER 2RN508 2RN49A IRN49A IRN508 UNIT l NON-ESS HEADER JRN51A IRN528 2RN528 2RN51A U2 NON-ESS HEADER I I I 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW POND 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/G

.l.

2RN84f-A SNSW PONO ~ _ _

1RN63A 1RN846A ~

~B 1B0/G t

!A 0/G lA 0/G 1 HN1'A t HN) R I \d OFF 2B DIG 2RN8498 ON I

2A 0/G J 2RN847A

~ A" ~'

LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 48 Figure 3b - Case Number 3 (Event Response)

Case 3 - Event Response Unit 1 LOCA ~N<;w PnNn

\. / ON LOOP bot h Unit s 5

l RN A 1RN6B I ~ 28 1J1 G No failures ON 1 i=-

18 0/G - --t"<l-----.!4---D'<J-- 28 IJ/G 1RN8488 2RN84 88 5 88 2RN69B JRN

~ ~

18 DIG JRN698 J

SNSW POND \ ____._ _ _ _ _ ___, ON 18 28 ESS 18 ESS 28 ESS HEADER ~ HEADER HEADER ON !RN53B I I 2RN47 A w

~I

~

II UNIT 2 NON-ESS HEADER 2RN50B 2RN49A

' ~ ~

1RN49A 1RN50B

UNIT l NON-ESS HEADER lR~ A U2 NDN-ESS HEADER

"" '°~ _J,____.J l ~N;A *1

~

2A ON I *1 ON 2A DI G i

" ess HEADER 2RN488 2RN67A

+ A I A ESS _

HEADER 2 A 0/ G

't'I ______J,.____

T 2 A ESS HEADER 2RN84: E 4 A SNSW PONO

1RN63A l RN846A

~ ~ 1B 0/G bit l A .IJ/ G JA 0/G l RNJA I RN2B I ci I ON 2B 0/ G *1 I 1RN8498 ON 2RN~t9B l IA 0/G 2 A 0/ G ~ A 2RN847A L AKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 49 Figure 4a - Case Number 4 (Initial Conditions)

Case 4 - Initial Conditions Aligned to SNSWP SNSW POND Unit 1 - Mode 1 I ~

lHN; A JRNG.B OFF 28 0/G o~~ I Unit 2 - Mode 1 All Equipment Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW PONO ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

~7

([

_J I I UNIT 2 NON-ESS ~

HEADER 2RN508 2RN49A IRN49A IRN508 UNIT l NON-ESS HEADER JRN51A IRN528 2RN528 2RN51A U2 NON-ESS HEADER I I I 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW POND 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/G

.l.

2RN84f-A SNSW PONO ~ _ _

1RN63A 1RN846A ~

~B 1B0/G t

!A DIG lA 0/G 1 HN1'A t HN) R I \d OFF 2B DIG 2RN8498 ON I

2A 0/G J 2RN847A

~ A" ~'

LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 50 Figure 4b - Case Number 4 (Event Response)

Case 4 - Event Response Unit 1 LOCA ~Nc;\,o,,.! PnNn ON LOOP both Units 1RN5A 1RN6B I ~ 28 IJ/G EOG 1A failure causes RN 1A Pump failure a nd 1A. ECCS failure ON I RN re mains aligned to SNSWP 18 0/G 28 IJ/ G 1RN8488 2RN84 8B JRN58B

~~~~

18 DIG 1RN69B

~

SNSW POND ~ ON 28 ESS 18 ESS 2B ESS 1RN48 HEADER HEADER HEADER J IRN53B ON 2RN47 A 1RN47A I I w

1 II

~

UNIT 2 NON-ESS UNIT l NON-ES S ~ U2 NDN-ESS HEADER HEADER HEADER 2RN50B 2RN49A B !RN5 1A 1RN528 2RN528 2RN5 1A 2RN488 1RN48B ON 2A ESS

~ ~

SNSW PONO I A ESS - - + + - - 2 A ESS 2A DI G HEADER HEADER HEADER

1 i

_,.:E4 2RN67A IRN67A ON I 2A 0/ G SNSW PONO

I RN6 3 A l RN846A I RNIA 1RN2B I ~

1

~OFF G JA 0/G 2B 0/ G

~

1

~

8 1B0/G OFF I ?RNR4~R i.------w- I A 0/G 2 A 0/ G ~ ol IRN847 A 2RN847A L AKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 51 Figure 5a - Case Number 5 (Initial Conditions)

Case 5 - Initial Conditions Aligned to Lake Wylie SNSW POND Unit 1 - Mode 1 1RN5A JRNGB I 'd I OFF 28 0/G Unit 2 - Mode 1 o~~

All Equipment Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW PONO ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

~7

([

_J I I UNIT 2 NON-ESS ~

HEADER 2RN508 2RN49A IRN49A I RN508 UNIT l NON-ESS HEADER JRN5 1A IRN528 2RN528 2RN51A U2 NON-ESS HEADER I I I 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW POND 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/G I D------!\ I RN843B 1 D----i 2RN846A I RN57A SNSW PONO t

!A 0/G 1RN846A lA 0/G L

1RN63A

~R 1B0/G l RNlA IRN:>R I \-d OFF 2B DIG 2RN8498 ON I

2AD/G ~

2RN847A F "~'

LAKE WYLI E A

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 52 Figure 5b - Case Number 5 (Event Response)

Case 5 - Event Response Unit 1 LOCA

~Nc;\,o,,.! PnNn ON LOOP bot h Unit s 1RN5A 1RN6B I ~ 28 0/G Loss of Lake Wylie, RN Syst em aligns t o SNSWP ON I 1RN3A Failure result s in loss of pi t A, lA and 2A RN Pumos, lA and 2A EDGs, lA and 2A ECCS 18 0/G 28 DIG 1RN8488 2RN8488

. ~,

JRN588

~:f~~

1RN69B

~

SNSW POND ~ ON J

28 ESS 18 ESS 2B ESS 1RN48 HEADER HEADER HEADER JRN53B ON 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS HEADER 2RN50B 2RN49A 2RN48B

~ UNIT 1RN48B B

l NON-ES S ~ U2 NON-ESS HEADER IRN5 1A 1RN528 2RN52B 2RN51A E E H AD R

~

2A ESS I A ESS - - + - + - - 2A ESS

~

SNSW PONO 2 G HEADER HEADER HEADER i 2RN67A IRN67A 2A 0/ G 2RN84f-A SNSW PONO .....

l RN846A 1 IRN63A I RNIA 1RN2B I ~

1

~OFF G JA 0/G 2B DI G ~ *1

~ l BDIG B

OFF I ?RNR4~R l+------cki---- I A 0/G 2A 0/ G IRN847A 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 53 Figure 6a - Case Number 6 (Initial Conditions)

Case 6 - I nitial Conditions Aligned t o Lake Wylie

~Nc;\,o,,.! PnNn Unit 1 - Mode 1 I 'd I ~

1RN5A JRNGB Unit 2 - Mode 1 2 G O FF EOG 2B Inoperable so close 2RN48B and 2RN50B RN Pump 2B Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW POND ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT l NON- ESS U2 NDN-ESS HEADER 1RN49A IRN508 HEADER HEADER 2RN508 2RN49A JRN5 1A IRN528 2RN528 2RN51A 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DIG HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/ G I D------!\ I RN843B 1 D--i 2RN846A IRN57A SNSW PONO t

!A DIG 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNlA IRN2R I \-d I OFF 2B DIG 2RN8498 ON

~ I A 0/ G 2A 0/ G ----cJ<J..----1 IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 54 Figure 6b - Case Number 6 (Event Response)

Case 6 - Event Response LOOP both Units RN System remains aligned to Lake Wylie ~N<:;\,o,,.! PflNn 1RN5A JRNGB I ~ 2

~ G RN Pump 2B not av ailable since Offsite Power lost and EDG2B lnop o~~ I EDG 1A failure causes RN Pump 1A failure, 1A ECCS failure 18 0/G 28 0/G 1RN848B 2RN8488 1RN58B

~~~~

18 DIG 1RN69B ON

~

SNSW POND ~ 18 ESS 28 ESS 28 ESS

! RN48 HEADER HEADER HEADER ON o - JJRN538 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT 1 NON-ESS U2 NON-ESS HEADER 1RN49A I RN508 HEADER HEADER 2RN50B 2RN49A JRN51A IRN528 2RN528 2RN51A 2RN488 1RN48B ON 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DI G HEADER HEADER HEADER ON I

1 i 2RN67A 1RN67A 2A 0/ G I D------!( I RN8 43B l D---i 2RN846A I RN57A SNSW PONO 1~

' 1RN846A lA 0/G 1RN63A L ~R 1B0/G

~

IRN2R I OF 2B l RNlA OFF I 0/ G 2RNA49R f.-----i,L::J- 1A 0/ G 2A 0/G IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 55 Figure 7a - Case Number 7 (Initial Conditions)

Case 7 - Init ial Conditions Aligned t o Lake Wylie

~Nc;\,o,,.! PnNn Unit 1 - Mode 1 I 'd I ~

1RN5A JRNGB Unit 2 - Mode 1 2 G O FF EOG 2B Inoperable so close 2RN48B and 2RN50B RN Pump 2B Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW POND ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT l NON-ESS U2 NON-ESS HEADER 1RN49A IRN508 HEADER HEADER 2RN508 2RN49A JRN5 1A IRN528 2RN528 2RN51A 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/ G I D------!\ I RN843B 1 D----i 2RN846A I RN57A SNSW PONO t

!A DIG 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNlA IRN2R I \-d I OFF 2B DIG 2RN8498 ON

~ I A 0/ G 2A 0/G IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 56 Figure 7b - Case Number 7 (Event Response)

Case 7 - Event Response Unit 1 LOCA LOOP bot h Units ~Nc;\,o,,.! PnNn RN System rem ains aligned to Lake Wylie 1RN5A JRNGB I ~ 2

~ G RN Pump 2B not av ailable since Offsite Power lost and EDG 2B lnop o~~ I EDG 1A failure ca uses RN Pump 1A failure, 1A ECCS failure 18 0/G 28 0/G 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B ON

~

SNSW POND ~ 1B ESS 2B ESS 28 ESS

! RN48 HEADER HEADER HEADER ON J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS HEADER 2RN508 2RN49A 2RN488 1RN49A 1RN508 1RN48B UNIT l NON-ESS ~ U2 NON-ESS HEADER 1RN5 1A IRN528 2RN528 2RN51A HEADER ON 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DI G HEADER HEADER HEADER ON I

1 i 2RN67A 1RN67A 2A 0/ G I D------!\ 1RN843B 1 D--i 2RN846A IRN57A SNSW PONO 1~

' 1RN846A lA 0/G 1RN63A L ~R 1B0/G

~

IRN2A I OF 2B l RNl A OFF I 0/ G 2RNA49R

~ I A 0/ G 2A 0/ G -----cJ<J...--- IRNA474 2RN847A LAKE WYLIE

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 57 Figure 8a - Case Number 8 (Initial Conditions)

Case 8 - Initial Conditions Aligned t o Lake Wylie

~Nc;\,o,,.! PnNn Unit 1 - Mode 1 I 'd I ~

1RN5A JRNGB Unit 2 - Shut down 2 G O FF EDG 2B Inopera ble so close 2RN48B and 2RNS0B RN Pump 2B Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW PONO ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT l NON-ESS U2 NON-ESS HEADER 1RN49A IRN508 HEADER HEADER 2RN508 2RN49A JRN5 1A IRN528 2RN528 2RN51A 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/ G I D------!\ I RN843B 1 D----i 2RN846A I RN57A SNSW PONO t

!A DIG 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNlA IRN2R I \-d I OFF 2B DIG 2RN8498 ON

~ I A 0/ G 2A 0/G IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 58 Figure 8b - Case Number 8 (Event Response)

Case 8 - Event Response Unit 1 LOCA LOOP bot h Unit s ~Nc;\,o,,.! PnNn RN System rem ains aligned to Lake Wylie 1RN5A JRNGB I ~ 2

~ G RN Pump 2B not av ailable since Offsite Power lost and EDG 2B lnop o~~ I EDG 1B failure ca uses RN Pump 1B failure, 1B ECCS failure 18 0/G 28 0/G 1RN848B 2RN848B 1RN58B

2RN698 i=--

1~

FF

~

SNSW POND ~ 18 ESS 28 ESS 28 ESS

! RN48 HEADER HEADER HEADER OFF J JRN538 2RN47A I I w

1 II UNIT 2 NON-ESS HEADER 2RN508 2RN49A

~ UNIT B

l NON-ESS~

HEADER 1RN5 1A IRN528 2RN52B 2RN51A U2 NON-ESS HEADER SNSW PONO

~ ~ ON I

1 ON 2A DI G i

2A ESS HEADER 2RN48B 2RN67A

+ "ess-----+-+-,- 2A HEADER 0/ G I D------!\ 1RN843B

, ss HEADER 1 D--i 2RN846A IRN57A SNSW PONO

!A 0/ G 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNl A IRN2R I \ -::::{ I ON 2B 0/ G 2RNA49R ON

~ 1 A 0/ G 2A 0/ G ----cJ<J..---.l IRNA47A 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 59 Figure 9a - Case Number 9 (Initial Conditions)

Case 9 - Initial Conditions Aligned t o Lake Wylie

~Nc;\,o,,.! PnNn Unit 1 - Mode 1 I 'd I ~

1RN5A JRNGB Unit 2 - Mode 1 2 G O FF EDG 2B Inoperable so close 2RN48B and 2RN50B RN Pump 2B Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW POND ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT l NON-ESS U2 NON-ESS HEADER 1RN49A IRN508 HEADER HEADER 2RN508 2RN49A JRN5 1A IRN528 2RN528 2RN51A 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/ G I D------!\ I RN843B 1 D----i 2RN846A I RN57A SNSW PONO t

!A DIG 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNlA IRN2R I \-d I OFF 2B DIG 2RN8498 ON

~ I A 0/ G 2A 0/G IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 60 Figure 9b - Case Number 9 (Event Response)

Case 9 - Event Response Unit 1 LOCA LOOP bot h Units Loss of Lake Wylie, RN System aligns to SNSWP SNS~1 POND RN Pump 2B not available since Offsite Power lost and EDG 2B lnop 1RN5A 1RN68

~

2" G EDG 1A failure causes 1RN3A failure, RN pit A loss, RN Pumps 1A, 2A failure OFF 18 0/G ~ 2 8 0/ G 1RN848B 2RN84 88 JRN5 88

>RN1lR 18 0/ G 1RN1lR SNSW PONO ON 18 ESS 28 ESS 28 ESS - - - - - - - - i 1RN48 HEADER HEADER HEADER ON 2RN47A 1RN47A w

..J

>- UNIT 2 NON-ESS ~ UNIT 1 NON-ESS ~ U2HEADER NDN-ESS

~

w HEADER 1RN49 A. 1R.N5 08 HEADER 1RN5 1A I RN52 8T2RN528 2 RN5 l A 2RN50B 2RN49A

"'"i 2RN488 1RN488 OFF 2 A ESS I A ESS 2 A ESS SNSW PONO ~ *I 2 G HEADER

I

>-------<~

HEADER

~----<-----

HEADER IRN:iA ~~

1RN67A OFF 2 A 0/ G 2RNR4 f-A SNSW POND " I ~

1RN63A '

1RN846A ~

l ~,G JA 0/G 1R rvr, l RN l A I RN2R OF 28 0/ G 2RNA49A OFF f.---t,L::J- 1 A 0/ G 2 A 0/ G ----cJ::i----l I RNR47 A 2RN847A L AKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 61 Figure 10a - Case Number 10 (Initial Conditions)

Case 10 - I nitial Conditions Aligned t o Lake Wylie

~Nc;\,o,,.! PnNn Unit 1 - Mode 1 I 'd I ~

1RN5A JRNGB Unit 2 - Mode 1 2 G O FF EDG 2B Inoperable so close 2RN48B and 2RN50B RN Pump 2B Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW POND ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT l NON- ESS U2 NON-ESS HEADER 1RN49A IRN508 HEADER HEADER 2RN508 2RN49A JRN5 1A IRN528 2RN528 2RN51A 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/ G I D------!\ I RN843B 1 D--i 2RN846A IRN57A SNSW PONO t

!A DIG 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNlA IRN2R I \-d I OFF 2B DIG 2RN8498 ON

~ I A 0/ G 2A 0/G IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 62 Figure 10b - Case Number 10 (Event Response)

Case 10 - Event Response Unit 1 LOCA LOOP bot h Units Loss of Lake Wylie, RN Syste m aligns to SNSWP ~Nc;\,o,,.! PnNn

~

RN Pump 28 not av ailable since Offsite Pow er lost and EDG 28 lnop 1RN5A 1RN6B I ~ 2 G EDG 1B failure causes 1RN48 failure, RN pit 8 loss, RN Pump 1B failure o~~ I 18 0/G 28 0/G 1RN8488 2RN8488 1RN588

2RN69B i=--

1~

FF

~

SNSW POND ~ 18 ESS 2B ESS 28 ESS

! RN48 HEADER HEADER HEADER OFF J JRN53B 2RN47A I I w

1 II UNIT 2 NON-ESS HEADER 2RN488

~ UNIT B

l NON-ESS~

HEADER 1RN5 1A IRN52B 2RN52B 2RN51A HEADER U2 NON-ESS SNSW PONO

~ ~

ON I

1 ON 2A DI G i

2A ESS HEADER 2RN67A + ""'-t-=!::-'" '~

HEADER 2A 0/ G IRN843B HEADER 1 D----l 2RN846A ~

1RN57A SNSW PONO 1RN63A I RNIA IRN28 I ~ I

!A 0/G ON l RN846A 1A 0/ G 28 0/ G L2RNA49R

~R 1B0/G ON i.-------w- I A 0/G 2A 0/G ~ ol IRN847A 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 63 Figure 11a - Case Number 11 (Initial Conditions)

Case 11 - Initial Conditions Aligned to Lake Wylie SNSW POND Unit 1 - Mode 1 I ~

1RN5A JRNGB OFF 28 0/G o~~ I Unit 2 - Shut down EOG 2B Operable 18 0/G 28 DIG RN Pump 2B inoperable wit h Unit 2 shut down 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW POND ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT l NON-ESS U2 NON-ESS HEADER 2RN508 2RN49A 1RN49A IRN508 HEADER HEADER JRN5 1A IRN528 2RN528 2RN51A 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW POND 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/G I D------!\ I RN843B 1 D----i 2RN846A I RN57A SNSW PONO t

!A 0/G 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNlA IRN2R I \-d I OFF 2B DIG 2RN8498 ON

~ I A 0/ G 2A 0/ G ----cJ<J..----l IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 64 Figure 11b - Case Number 11 (Event Response)

Case 11

Event Response Unit 1 LOCA 1RN3A failure causes RN pit A loss, RN Pumps lA& 2A failure, EOG 1A.&2A failure Loss of Lake Wylie, RN Syst em aligns to SNSWP ~N<:;\,o,,.! PflNn LOOP bot h Units 1RN5A 1RN6B I ~ ON RN Pump 28 inoperable wit h Unit 2 shut down o~~ I 28 0/ G 18 0/G 28 0/G 1RN848B 2RN848B

______:J~~~

1RN58B I

SNSW PONO ~

! RN48 I

18 ON rn *~ ,

ON 28 ESS HEADER

_o--i 2RN47A t-.

J 1RN47A 18 ESS HEADER 2B ESS HEADER w

1 II UNIT 2 NON-ESS HEADER 2RN508 2RN49A 2RN488

~ UNIT 1 NON-ESS~

1RN488 B HEADER 1RN5 1A IRN52B 2RN528 2RN51A U2 NON-ESS HEADER 2A ESS ! A ESS - + - - + - - - 2A ESS

~ ~ ~

SNSW PONO 2 G HEADER HEADER HEADER OFF I

1 i 2RN67A JRN67A 2A 0/G 2RN84f-A SNSW PONO .....

l RN846A 1 1RN63A IRNJA IRN28 I ~

1

~OFF G

0 lA D/G 28 0/ G 4 i . - W - 1Rrvr, OFF I 2RN849B

~ 1 A 0/ G 2A 0/ G ----c,k::J...-. IRN847A 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 65 Figure 12a - Case Number 12 (Initial Conditions)

Case 12 - I nitial Conditions Aligned t o Lake Wylie

~Nc;\,o,,.! PnNn Unit 1 - Mode 1 I 'd I ~

1RN5A JRNGB Unit 2 - Shut down 2 G O FF EDG 2B Inoperab le so close 2RN48B and 2RNS0B RN Pump 2B Operable 18 0/G 28 DIG 1RN848B 2RN848B 1RN58B

~~~~

18 DIG 1RN69B

~

SNSW PONO ~ OFF 28 ESS 1B ESS 2B ESS

! RN48 HEADER HEADER HEADER O FF J JRN53B 2RN47A 1RN47A I I w

1 II UNIT 2 NON-ESS ~ UNIT l NON- ESS U2 NDN-ESS HEADER 1RN49A IRN508 HEADER HEADER 2RN508 2RN49A JRN5 1A IRN528 2RN528 2RN51A 2RN488 1RN48B OFF 2A ESS I A ESS - - + + - - 2A ESS

~ ~

SNSW PONO 2A DI G HEADER HEADER HEADER OFF I

1 i 2RN67A !RN67A 2A 0/ G I D------!\ I RN843B 1 D--i 2RN846A IRN57A SNSW PONO t

!A DIG 1RN846A lA 0/G 1RN63A L ~R 1B0/G l RNlA IRN2R I \-d I OFF 2B DIG 2RN8498 ON

~ I A 0/ G 2A 0/G IRNA474 2RN847A LAKE WYLI E

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 66 Figure 12b - Case Number 12 (Event Response)

Case 12

Event Response Unit 1 LOCA LOOP both Units Loss of Lake Wylie, RN System aligns to SNSWP SNSW PONO 1RN3A failure causes RN pit A loss, RN Pumps lA& 2A failure, EOG 1A.&2A failure I

1RN5A 1RNhR

~

OFF I 2

~.., G 18 0/G 28 0/G 1RN848B 2RN848B JRN58B SNSW POND ~

IRN48 ON "ON.~,

2B ESS HEADER

_____:]"'""

1=-- 1B ESS HFADFR 2B ESS HFAOFR w

I I o--i 2RN47A J lRN47A

1 II UNIT 2 NON-ESS UNIT l NON-ESS U2 NON-ESS HEADER HEADER HEADER 2RN508 2RN49A IRN49A I RN50B JRN5 1A IRN528 2RN52B 2RN51A 2RN48B 1RN48B

~ 2A

~I 2A ESS 1A ESS ESS

~ ~ ~

<:;N<:;W PONO 2 G HEADER HEADER HEADER OFF I i 2RN67A 1RN67A 2A 0/ G I f7-.--C"r' JRN8438

"""~

SNSW PONO l D-i 1RN57A l RN63A 1RN846A

~ ----l--.,

0 1 G JA 0/G ~ 180/G l RNJA IHNdB I ~ OFF 2B DI G B OFF I 2RN8498

~ l A 0/ G 2A 0/ G -----c,lo----+i IANA47A 2RN847A LAKE WYLIE

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 67 Table 2 below shows the NSWS flow rates (in gallons per minute) to essential components based on the twelve scenarios described in Table 1 above. In all cases, the NSWS flow is within required ranges, and the minimum number of essential components are available to achieve the required heat removal requirements to support the required Safety Function.

Additionally, the NSWS pump flow rates and NSWS Essential Header pressures are within the required range. As previously discussed, not all possible combinations are shown, but the combinations that are presented bound other possible combinations (i.e., failure of valve 1RN3A is presented, which bounds the corresponding opposite train failure of valve 1RN4B).

Please refer to the following definitions for Table 2:

CA - Auxiliary Feedwater HX - Heat Exchanger KD - Diesel Jacket Water Cooling NS - Containment Spray YC - Control Room Chilled Water NW - Containment Penetration Valve Ejection KF - Spent Fuel Cooling

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 68 Table 2 - NSWS Scenarios and Flow Rates to Essential Components Required Case Case Case Case Case Case Case Case Case Case Case Case Component Flow Range* 1 2 3 4 5 6 7 8 9 10 11 12 NSWS Pump 1A 8600 - 25800 13427 13683 14340 0 0 0 0 13428 0 13653 0 0 Discharge Flow NSWS Pump 1B 8600 - 25800 13631 15077 15640 17153 15785 19603 19517 0 20615 0 21147 20615 Discharge Flow NSWS Pump 2A 8600 - 25800 11776 12227 13342 16838 0 17096 15699 11778 0 12174 0 0 Discharge Flow NSWS Pump 2B 8600 - 25800 8636 9148 9351 11597 9403 0 0 0 0 0 0 0 Discharge Flow NSWS Train A Strainer 600 - 1600 1669 1733 1715 854 0 812 829 1668 0 1733 0 0 Backwash NSWS Train B Strainer 600 - 1600 1313 1356 1351 1323 1350 722 724 0 742 0 730 742 Backwash KC HX 1A 4925 - 14000 6418 7895 7647 7634 0 6550 6695 7860 0 7907 0 0 KC HX 1B 4925 - 14000 6887 7910 7872 7419 7639 6637 6484 0 6954 0 6697 6954 KC HX 2A 4925 - 14000 6169 7863 7607 7531 0 6317 6428 7810 0 7872 0 0 KC HX 2B 4925 - 14000 7026 8088 8033 7561 7879 6808 6697 0 7193 0 6928 7193 KD HX 1A 600 - 1400 1044 1016 987 0 0 0 0 1069 0 1017 0 0 KD HX 1B 600 - 1400 1188 1033 1028 978 1007 1078 1082 0 917 0 883 917 KD HX 2A 600 - 1400 1074 1142 1114 1087 0 1057 1087 1160 0 1143 0 0 KD HX 2B 600 - 1400 1554 1465 1458 1391 1432 0 0 0 0 0 1254 0 NS HX 1A 2200 - 5000 2909 3056 2961 0 0 0 0 3147 0 3056 0 0 NS HX 1B 2200 - 5000 2647 3041 3026 2867 2952 0 2505 0 2687 0 2588 2687 NS HX 2A 2200 - 5000 0 0 0 0 0 0 0 0 0 0 0 0 NS HX 2B 2200 - 5000 0 0 0 0 0 0 0 0 0 0 0 0 NSWS CA, NW, KF 600 600 600 600 0 0 0 0 600 0 600 0 0 Makeup 1A NSWS CA, NW, KF 600 600 600 600 600 600 600 600 0 600 0 600 600 Makeup 1B NSWS CA, NW, KF 600 600 600 600 600 0 600 600 0 0 600 0 0

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 69 Required Case Case Case Case Case Case Case Case Case Case Case Case Component Flow Range* 1 2 3 4 5 6 7 8 9 10 11 12 Makeup 2A NSWS CA, NW, KF 600 600 600 600 600 600 0 0 0 0 0 0 0 Makeup 2B YC Chiller Cond 'A' 1100 - 1600 1529 1883 1823 0 0 0 0 1760 0 1771 0 0 YC Chiller Cond 'B' 1100 - 1600 0 0 0 1561 1608 1397 1365 0 1463 0 1409 1463 Unit 1 Non Ess 0 - 3400 0 0 0 0 0 3400 0 0 0 0 0 0 Header**

Unit 2 Non Ess 0 - 3400 3400 0 3400 3400 0 0 0 0 0 0 0 0 Header**

1A Essential Header Min 35 PSIG 72.5 78.3 76.4 71.4 0 64.0 67 72.3 0 78.4 0 0 Press 1RNPT5020 1B Essential Header Min 35 PSIG 72.6 77.4 76.7 72.3 76.3 59.6 59.7 0 62.9 0 60.6 62.9 Press 1RNPT5030 2A Essential Header Min 35 PSIG 72.6 78.6 65.5 71.4 0 64.1 67.1 72.7 0 78.7 0 0 Press 2RNPT5020 2B Essential Header Min 35 PSIG 72.3 77.1 76.2 71.2 76.3 59.4 59.8 0 63 0 60.7 63 Press 2RNPT5030

Range of allowable flow values is from an approved Catawba Calculation (Nuclear Service Water System Test Acceptance Criteria)

- NSWS flow to Non-Essential Headers is not required and is not set per NSWS Flow Balance Procedures, so required minimum is zero. Flow value reflects total nominal flow rates of components, from Design Basis Document for the NSWS (Design Basis Specification for the Nuclear Service Water System (RN).

U.S. Nuclear Regulatory Commission RA-17-0051, Enclosure Page 70 3.2 Clarification of CNS UFSAR Statements The following is a clarification of CNS UFSAR Section 9.2.1.2, RN (i.e., NSWS) Pumphouse Section:

UFSAR Statement: The operation of any two pumps on either or both supply lines is sufficient to supply all cooling water requirements for unit startup, cooldown, and refueling and post-accident operation of two units.

Explanation: While the NSWS has four pumps, any combination of two pumps is adequate for all modes of operation for both units, including post-accident conditions. It takes two pumps (any unit or train, just any two pumps), to supply cooling water to any combination of the four operations listed. This is possible due to the design of the NSWS, which allows NSWS flow between units and between trains, depending upon the system alignment. This capability is evident in the above Case Numbers 5-8 in Table 1, which depict the accident response of the NSWS and show that two NSWS pumps have adequate capacity to support LOCA loads on one unit and hot standby loads on the other unit. In the preceding scenarios, the Initial Conditions diagram depicts the 1A NSWS Pump in operation supplying flow to all four NSWS Essential Headers (1A, 1B, 2A, 2B). This system alignment is typical for normal operation. During the summer months, it is typical to start a second NSWS pump to support cooling water flow demands. Any other pump can be in service to supply this cooling water flow demand.

UFSAR Statement: However, one pump has sufficient capacity to supply all cooling water requirements during normal power operation of both units or during post accident conditions if the unaffected unit is already in cold shutdown.

Explanation: As described above, the NSWS will typically have one pump in operation supplying cooling water flow demands for both units during normal operation. The second part of the statement concerns the accident response of the NSWS which results in one remaining NSWS supplying both units (the NSWS one pump flow balance), and is depicted in Case Number 11 in Table 1. With one unit shutdown and the other unit in Mode 1, one NSWS pump has sufficient capacity to supply the flow demands for both the shutdown unit and the accident unit.

to RA-17-0051 Attachment 1 Revised Catawba Technical Specification Marked Up Pages

AC Sources - Operating 3.8.1 3.8 ELECTRICAL POWER SYSTEMS 3.8.1 AC SourcesOperating LCO 3.8.1 The following AC electrical sources shall be OPERABLE:

a. Two qualified circuits between the offsite transmission network and the Onsite Essential Auxiliary Power System; and

b. Two diesel generators (DGs) capable of supplying the Onsite Essential Auxiliary Power Systems; and

c. One qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES); and

d. One DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES; AND The automatic load sequencers for Train A and Train B shall be OPERABLE.

APPLICABILITY: MODES 1, 2, 3, and 4.

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

The opposite unit electrical power sources in LCO 3.8.1.c and LCO 3.8.1.d are not required to be OPERABLE when the associated shared systems are inoperable.

Catawba Units 1 and 2 3.8.1-1 Amendment Nos. 253/248

AC Sources - Operating 3.8.1 ACTIONS

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

LCO 3.0.4.b is not applicable to DGs.

CONDITION REQUIRED ACTION COMPLETION TIME A. One LCO 3.8.1.a offsite A.1 Perform SR 3.8.1.1 for 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months circuit inoperable. required OPERABLE offsite circuit(s). AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from A.2 Declare required feature(s) discovery of no with no offsite power offsite power to one available inoperable when train concurrent with its redundant required inoperability of feature(s) is inoperable. redundant required feature(s)

AND A.3 Restore offsite circuit to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months OPERABLE status.

AND 6 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b Catawba Units 1 and 2 3.8.1-2 Amendment Nos. 253/248

AC Sources - Operating 3.8.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME B. One LCO 3.8.1.b DG B.1 Verify both DGs on the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months inoperable. opposite unit OPERABLE.

AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND B.12 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND B.23 Declare required feature(s) 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from supported by the discovery of inoperable DG inoperable Condition B when its required concurrent with redundant feature(s) is inoperability of inoperable. redundant required feature(s)

AND B.34.1 Determine OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months DG(s) is not inoperable due to common cause failure.

OR 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months B.34.2 Perform SR 3.8.1.2 for OPERABLE DG(s).

AND (continued)

Catawba Units 1 and 2 3.8.1-3 Amendment Nos. 173/165

AC Sources - Operating 3.8.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME B. (continued) B.5 Ensure availability of Prior to entering the Emergency Supplemental extended Completion Power Source (ESPS). Time of ACTION B.6 AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND B.4B.6 Restore DG to OPERABLE 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from status. discovery of unavailable ESPS AND 6 days from discovery of failure to meet LCO 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from discovery of unavailable ESPS when in extended Completion Time AND 14 days AND 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b Catawba Units 1 and 2 3.8.1-4 Amendment Nos. 253/248

AC Sources - Operating 3.8.1 ACTIONS C. Required Action and C.1.1 Restore both DGs on the 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion opposite unit to Time of Required Action OPERABLE status.

B.1 not met.

OR C.1.2 Restore LCO 3.8.1.b DG to OPERABLE status.

D. LCO 3.8.1.c offsite -------------------NOTE------------------

circuit inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems Operating," when Condition D is entered with no AC power source to a train.

D.1 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND D.2 Declare NSWS, CRAVS, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from CRACWS or ABFVES with discovery of no no offsite power available offsite power to one inoperable when the train concurrent with redundant NSWS, CRAVS, inoperability of CRACWS or ABFVES is redundant required inoperable. feature(s)

AND D.3 Declare NSWS, CRAVS, 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CRACWS and ABFVES supported by the inoperable offsite circuit inoperable.

Catawba Units 1 and 2 3.8.1-5 Amendment Nos. 253/248

AC Sources - Operating 3.8.1 ACTIONS E. LCO 3.8.1.d DG -------------------NOTE------------------

inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems Operating," when Condition E is entered with no AC power source to a train.

E.1 Verify both LCO 3.8.1.b 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months DGs OPERABLE, the opposite units DG AND OPERABLE and ESPS available. Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND E.2 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND E.3 Declare NSWS, CRAVS, 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from CRACWS or ABFVES discovery of supported by the Condition E inoperable DG inoperable concurrent with when the redundant inoperability of NSWS, CRAVS, CRACWS redundant required or ABFVES is inoperable. feature(s)

AND Catawba Units 1 and 2 3.8.1-6 Amendment Nos. 253/248

AC Sources - Operating 3.8.1 ACTIONS E. (continued) E.4.1 Determine OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months DG(s) is not inoperable due to common cause failures.

OR E.4.2 Perform SR 3.8.1.2 for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months OPERABLE DG(s).

AND E.5 Declare NSWS, CRAVS, 14 days CRACWS and ABFVES supported by the inoperable DG inoperable.

F. Required Action and F.1.1 Restore both LCO 3.8.1.b 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion DGs and opposite units Time of Required Action DG to OPERABLE status E.1 not met. and ESPS to available status.

OR F.1.2 Restore LCO 3.8.1.d DG to OPERABLE status.

OR F.1.3 Declare NSWS, CRAVS, CRACWS and ABFVES supported by the inoperable DG inoperable.

Catawba Units 1 and 2 3.8.1-7 Amendment Nos. 253/248

AC Sources - Operating 3.8.1 ACTIONS CG. Two LCO 3.8.1.a offsite CG.1 Declare required feature(s) 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months from circuits inoperable. inoperable when its discovery of redundant required Condition C G OR feature(s) is inoperable. concurrent with inoperability of One LCO 3.8.1.a offsite redundant required circuit that provides features power to the NSWS, CRAVS, CRACWS and AND ABFVES inoperable and the required LCO 3.8.1.c CG.2 Restore one offsite circuit 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months offsite circuit inoperable. to OPERABLE status.

(continued)

Catawba Units 1 and 2 3.8.1-8 Amendment Nos. 253/248

AC Sources - Operating 3.8.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME DH. One LCO 3.8.1.a offsite -------------------NOTE------------------

circuit inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, AND "Distribution Systems Operating," when Condition D H is One LCO 3.8.1.b DG entered with no AC power source inoperable. to any train.

DH.1 Restore offsite circuit to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months OPERABLE status.

OR DH.2 Restore DG to OPERABLE 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months status.

EI. Two LCO 3.8.1.b DGs EI.1 Restore one DG to 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months inoperable. OPERABLE status.

OR LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and LCO 3.8.1.d DG inoperable.

FJ. One automatic load FJ.1 Restore automatic load 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months sequencer inoperable. sequencer to OPERABLE status.

Catawba Units 1 and 2 3.8.1-9 Amendment Nos. 173/165

AC Sources - Operating 3.8.1 ACTIONS (continued)

GK. Required Action and GK.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months associated Completion Time of Condition A, BC, AND C, D, E, or F, G, H, I, or J not met. GK.2 Be in MODE 5. 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months OR Required Action and associated Completion Time of Required Action B.2, B.3, B.4.1, B.4.2, or B.6 not met.

OR Required Action and associated Completion Time of Required Action E.2, E.3, E.4.1, E.4.2, or E.5 not met.

HL. Three or more LCO HL.1 Enter LCO 3.0.3. Immediately 3.8.1.a and LCO 3.8.1.b AC sources inoperable.

Catawba Units 1 and 2 3.8.1-10 Amendment Nos. 173/165

AC Sources - Operating 3.8.1 SURVEILLANCE REQUIREMENTS

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

SR 3.8.1.1 through SR 3.8.1.20 are only applicable to LCO 3.8.1.a and LCO 3.8.1.b AC sources. SR 3.8.1.21 is only applicable to LCO 3.8.1.c and LCO 3.8.1.d AC sources.

SURVEILLANCE FREQUENCY SR 3.8.1.1 Verify correct breaker alignment and indicated power In accordance with availability for each offsite circuit. the Surveillance Frequency Control Program SR 3.8.1.2 ---------------------------------NOTES-------------------------------

1. Performance of SR 3.8.1.7 satisfies this SR.

2. All DG starts may be preceded by an engine prelube period and followed by a warmup period prior to loading.

3. A modified DG start involving idling and gradual acceleration to synchronous speed may be used for this SR as recommended by the manufacturer.

When modified start procedures are not used, the time, voltage, and frequency tolerances of SR 3.8.1.7 must be met.

Verify each DG starts from standby conditions and In accordance with achieves steady state voltage > 3950 V and < 4580 V, the Surveillance and frequency > 58.8 Hz and < 61.2 Hz. Frequency Control Program (continued)

Catawba Units 1 and 2 3.8.1-11 Amendment Nos. 263/259

AC Sources - Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.20 --------------------------------------NOTE----------------------------

All DG starts may be preceded by an engine prelube period.

Verify when started simultaneously from standby In accordance with condition, each DG achieves, in < 11 seconds, voltage of the Surveillance

> 3950 V and frequency of > 57 Hz and maintains steady Frequency Control state voltage > 3950 V and < 4580 V, and frequency Program

> 58.8 Hz and < 61.2 Hz.

SR 3.8.1.21 For the LCO 3.8.1.c and LCO 3.8.1.d AC electrical In accordance with sources, SR 3.8.1.1, SR 3.8.1.2, SR 3.8.1.4, SR 3.8.1.5, the Surveillance and SR 3.8.1.6 are required to be met. Frequency Control Program Catawba Units 1 and 2 3.8.1-21 Amendment Nos. 263/259 to RA-17-0051 Attachment 2 Revised McGuire Technical Specification Marked Up Pages

AC Sources - Operating 3.8.1 3.8 ELECTRICAL POWER SYSTEMS 3.8.1 AC Sources Operating LCO 3.8.1 The following AC electrical sources shall be OPERABLE:

a. Two qualified circuits between the offsite transmission network and the Onsite Essential Auxiliary Power System; and

b. Two diesel generators (DGs) capable of supplying the Onsite Essential Auxiliary Power Systems; and

c. One qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES); and

d. One DG from the opposite unit necessary to supply power to the NSWS, CRAVS, CRACWS and ABFVES; AND The automatic load sequencers for Train A and Train B shall be OPERABLE.

APPLICABILITY: MODES 1, 2, 3, and 4.

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

The opposite unit electrical power sources in LCO 3.8.1.c and LCO 3.8.1.d are not required to be OPERABLE when the associated shared systems are inoperable.

McGuire Units 1 and 2 3.8.1-1 Amendment No. 221/203

AC Sources - Operating 3.8.1 ACTIONS

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

LCO 3.0.4.b is not applicable to DGs.

CONDITION REQUIRED ACTION COMPLETION TIME A. One LCO 3.8.1.a offsite A.1 Perform SR 3.8.1.1 for 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months circuit inoperable. required OPERABLE offsite circuit(s). AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from A.2 Declare required feature(s) discovery of no with no offsite power offsite power to one available inoperable when train concurrent with its redundant required inoperability of feature(s) is inoperable. redundant required feature(s)

AND A.3 Restore offsite circuit to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months OPERABLE status.

AND 6 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b McGuire Units 1 and 2 3.8.1-2 Amendment No. 221/203

AC Sources - Operating 3.8.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME B. One LCO 3.8.1.b DG B.1 Verify LCO 3.8.1.d DG 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months inoperable. OPERABLE.

AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND B.12 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND B.23 Declare required feature(s) 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from supported by the discovery of inoperable DG inoperable Condition B when its required concurrent with redundant feature(s) is inoperability of inoperable. redundant required feature(s)

AND B.34.1 Determine OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months DG(s) is not inoperable due to common cause failure.

OR 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months B.34.2 Perform SR 3.8.1.2 for OPERABLE DG(s).

AND (continued)

McGuire Units 1 and 2 3.8.1-3 Amendment No. 184/166

AC Sources - Operating 3.8.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME B. (continued) B.5 Ensure availability of Prior to entering the Emergency Supplemental extended Completion Power Source (ESPS). Time of ACTION B.6 AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND B.4B.6 Restore DG to OPERABLE 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from status. discovery of unavailable ESPS **

AND 6 days from discovery of failure to meet LCO 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from discovery of unavailable ESPS when in extended Completion Time AND 14 days AND 17 days from discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b McGuire Units 1 and 2 3.8.1-4 Amendment No. 293/272

AC Sources - Operating 3.8.1 ACTIONS C. Required Action and C.1.1 Restore LCO 3.8.1.d DG to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion OPERABLE status.

Time of Required Action B.1 not met. OR C.1.2 Restore LCO 3.8.1.b DG to OPERABLE status.

D. LCO 3.8.1.c offsite ------------------NOTE--------------------

circuit inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, Distribution Systems - Operating, when Condition D is entered with no AC power source to a train.

D.1 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND D.2 Declare NSWS, CRAVS, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from CRACWS or ABFVES with discovery of no no offsite power available offsite power to one inoperable when the train concurrent with redundant NSWS, CRAVS, inoperability of CRACWS or ABFVES is redundant required inoperable. feature(s)

AND D.3 Declare NSWS, CRAVS, 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months CRACWS and ABFVES supported by the inoperable offsite circuit inoperable.

McGuire Units 1 and 2 3.8.1-5 Amendment No. 293/272

AC Sources - Operating 3.8.1 ACTIONS E. LCO 3.8.1.d DG ------------------NOTE--------------------

inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, Distribution Systems - Operating, when Condition E is entered with no AC power source to a train.

E.1 Verify both LCO 3.8.1.b 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months DGs OPERABLE and ESPS available. AND Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter AND E.2 Perform SR 3.8.1.1 for the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months required offsite circuit(s).

AND Once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter AND E.3 Declare NSWS, CRAVS, 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months from CRACWS or ABFVES discovery of supported by the Condition E inoperable DG inoperable concurrent with when the redundant inoperability of NSWS, CRAVS, CRACWS redundant required or ABFVES is inoperable. feature(s)

AND (continued)

McGuire Units 1 and 2 3.8.1-6 Amendment No. 293/272

AC Sources - Operating 3.8.1 ACTIONS E. (continued) E.4.1 Determine OPERABLE 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months DG(s) is not inoperable due to common cause failures.

OR E.4.2 Perform SR 3.8.1.2 for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months OPERABLE DG(s).

AND E.5 Declare NSWS, CRAVS, 14 days CRACWS and ABFVES supported by the inoperable DG inoperable.

F. Required Action and F.1.1 Restore both LCO 3.8.1.b 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated Completion DGs to OPERABLE status Time of Required Action and ESPS to available E.1 not met. status.

OR F.1.2 Restore LCO 3.8.1.d DG to OPERABLE status.

OR F.1.3 Declare NSWS, CRAVS, CRACWS and ABFVES supported by the inoperable DG inoperable.

McGuire Units 1 and 2 3.8.1-7 Amendment No. 293/272

AC Sources - Operating 3.8.1 ACTIONS C.G Two LCO 3.8.1.a offsite CG.1 Declare required feature(s) 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months from circuits inoperable. inoperable when its discovery of redundant required Condition C G OR feature(s) is inoperable. concurrent with inoperability of One LCO 3.8.1.a offsite redundant required circuit that provides feature(s) power to the NSWS, CRAVS, CRACWS and AND ABFVES inoperable and the required LCO 3.8.1.c CG.2 Restore one offsite circuit 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months offsite circuit inoperable. to OPERABLE status.

(continued)

- A Train EDGs are allowed to be inoperable for a total of 14 days for the correction of a degraded condition on the 'A' Train supply piping from the Standby Nuclear Service Water Pond (SNSWP). The 14 days may be taken consecutively or in parts until completion of the activity, or by March 1, 2017 whichever occurs first. During the period in which the 'A' Train NSWS supply piping from the SNSWP is not available, the A Train NSWS will remain aligned to Lake Norman until the system is ready for post maintenance testing. Any maintenance that is performed on the remaining portions of A Train NSWS during the period in which the A NSWS from the SNSWP supply piping is not available will be limited to a 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months completion time. The latter will not count against the 14 day completion time. Allowance of the extended Completion Time is contingent on meeting the Compensatory Measures and Commitments as described in MNS LAR submittal correspondence letter MNS-16-005.

McGuire Units 1 and 2 3.8.1-8 Amendment No. 293/272

AC Sources - Operating 3.8.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME DH. One LCO 3.8.1.a offsite ------------------NOTE-------------------

circuit inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, AND "Distribution Systems Operating," when Condition D H is One LCO 3.8.1.b DG entered with no AC power source inoperable. to any train.

DH.1 Restore offsite circuit to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months OPERABLE status.

OR DH.2 Restore DG to OPERABLE 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months status.

EI. Two LCO 3.8.1.b DGs EI.1 Restore one DG to 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months inoperable. OPERABLE status.

OR LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and LCO 3.8.1.d DG inoperable FJ. One automatic load FJ.1 Restore automatic load 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months sequencer inoperable. sequencer to OPERABLE status.

McGuire Units 1 and 2 3.8.1-9 Amendment No. 184/166

AC Sources - Operating 3.8.1 ACTIONS (continued)

GK. Required Action and GK.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months associated Completion Time of Condition A, B, AND C, D, E, orC, F, G, H, I, or J not met. GK.2 Be in MODE 5. 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months OR Required Action and associated Completion Time of Required Action B.2, B.3, B.4.1, B.4.2, or B.6 not met.

OR Required Action and associated Completion Time of Required Action E.2, E.3, E.4.1, E.4.2, or E.5 not met.

HL. Three or more LCO HL.1 Enter LCO 3.0.3. Immediately 3.8.1.a and LCO 3.8.1.b AC sources inoperable.

McGuire Units 1 and 2 3.8.1-10 Amendment No. 184/166

AC Sources - Operating 3.8.1 SURVEILLANCE REQUIREMENTS

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

SR 3.8.1.1 through SR 3.8.1.20 are only applicable to LCO 3.8.1.a and LCO 3.8.1.b AC sources. SR 3.8.1.21 is only applicable to LCO 3.8.1.c and LCO 3.8.1.d AC sources.

SURVEILLANCE FREQUENCY SR 3.8.1.1 Verify correct breaker alignment and indicated power In accordance with availability for each offsite circuit. the Surveillance Frequency Control Program SR 3.8.1.2 --------------------------------NOTES--------------------------------

1. Performance of SR 3.8.1.7 satisfies this SR.

2. All DG starts may be preceded by an engine prelube period and followed by a warmup period prior to loading.

3. A modified DG start involving idling and gradual acceleration to synchronous speed may be used for this SR as recommended by the manufacturer.

When modified start procedures are not used, the time, voltage, and frequency tolerances of SR 3.8.1.7 must be met.

Verify each DG starts from standby conditions and In accordance with achieves steady state voltage t 3740 V and d 4580 V, the Surveillance and frequency t 58.8 Hz and d 61.2 Hz. Frequency Control Program (continued)

McGuire Units 1 and 2 3.8.1-11 Amendment No. 261/241

AC Sources - Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.20 --------------------------------NOTES--------------------------------

All DG starts may be preceded by an engine prelube period.

Verify when started simultaneously from standby In accordance with condition, each DG achieves, in d 11 seconds, voltage of the Surveillance t 3740 V and frequency of t 57 Hz and maintains steady Frequency Control state voltage t 3740 V and d 4580 V, and frequency Program t 58.8 Hz and d 61.2 Hz.

SR 3.8.1.21 For the LCO 3.8.1.c and LCO 3.8.1.d AC electrical In accordance with sources, SR 3.8.1.1, SR 3.8.1.2, SR 3.8.1.4, SR 3.8.1.5, the Surveillance and SR 3.8.1.6 are required to be met. Frequency Control Program McGuire Units 1 and 2 3.8.1-21 Amendment No. 261/241 to RA-17-0051 Attachment 3 Revised Catawba Technical Specification Bases Marked Up Pages (For Information Only)

AC SourcesOperating B 3.8.1 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.1 AC SourcesOperating BASES BACKGROUND The unit Essential Auxiliary Power Distribution System AC sources consist of the offsite power sources (preferred power sources, normal and alternate(s)), and the onsite standby power sources (Train A and Train B diesel generators (DGs)). As required by 10 CFR 50, Appendix A, GDC 17 (Ref. 1), the design of the AC electrical power system provides independence and redundancy to ensure an available source of power to the Engineered Safety Feature (ESF) systems.

The onsite Class 1E AC Distribution System is divided into redundant load groups (trains) so that the loss of any one group does not prevent the minimum safety functions from being performed. Each train has connections to two preferred offsite power sources and a single DG.

At the 600V level of the onsite Class 1E AC Distribution System, each unit has one motor control center (MCC), 1EMXG and 2EMXH, that each supply power to a train of shared systems. The term shared systems is defined as the shared components of Train A or Train B of Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES). The MCC 1EMXG is normally aligned to receive power from load center 1ELXA but if desired or required to maintain operability of the Train A shared systems, can be swapped to receive power from load center 2ELXA. The MCC 2EMXH is normally aligned to receive power from load center 2ELXB but if desired or required to maintain operability of the Train B shared systems, can be swapped to receive power from load center 1ELXB.

There are also provisions to accommodate the connecting of the Emergency Supplemental Power Source (ESPS) to one train of either units Class 1E AC Distribution System. The ESPS consists of two 50%

capacity non-safety related commercial grade DGs. Manual actions are required to align the ESPS to the station and only one of the stations four onsite Class 1E Distribution System trains can be supplied by the ESPS at any given time. The ESPS is made available to support extended Completion Times in the event of an inoperable DG as well as a defense-in-depth source of AC power to mitigate a station blackout event. The ESPS would remain disconnected from the Class 1E AC Distribution System unless required for supplemental power to one of the four 4.16 Catawba Units 1 and 2 B 3.8.1-1 Revision No. 6

kV ESF buses.

From the transmission network, two electrically and physically separated circuits provide AC power, through step down station auxiliary transformers, to the 4.16 kV ESF buses. A detailed description of the offsite power network and the circuits to the Class 1E ESF buses is found in the UFSAR, Chapter 8 (Ref. 2).

A qualified offsite circuit consists of all breakers, transformers, switches, interrupting devices, cabling, and controls required to transmit power from the offsite transmission network to the onsite Class 1E ESF bus(es).

Certain required unit loads are returned to service in a predetermined sequence in order to prevent overloading the transformer supplying offsite power to the onsite Class 1E Distribution System. Within 1 minute after the initiating signal is received, all automatic and permanently connected loads needed to recover the unit or maintain it in a safe condition are returned to service via the load sequencer.

The onsite standby power source for each 4.16 kV ESF bus is a dedicated DG. DGs A and B are dedicated to ESF buses ETA and ETB, respectively. A DG starts automatically on a safety injection (SI) signal (i.e., low pressurizer pressure or high containment pressure signals) or on an ESF bus degraded voltage or undervoltage signal (refer to LCO 3.3.5, "Loss of Power (LOP) Diesel Generator (DG) Start Instrumentation"). After the DG has started, it will automatically tie to its respective bus after offsite power is tripped as a consequence of ESF bus undervoltage or degraded voltage, independent of or coincident with an SI signal. With no SI signal, there is a 10 minute delay between degraded voltage signal and the DG start signal. The DGs will also start and operate in the standby mode without tying to the ESF bus on an SI signal alone. Following the trip of offsite power, a sequencer strips loads from the ESF bus. When the DG is tied to the ESF bus, loads are then sequentially connected to its respective ESF bus by the automatic load sequencer. The sequencing logic controls the permissive and starting signals to motor breakers to prevent overloading the DG by automatic load application.

In the event of a loss of preferred power, the ESF electrical loads are automatically connected to the DGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a Design Basis Accident (DBA) such as a loss of coolant accident (LOCA).

Certain required unit loads are returned to service in a predetermined sequence in order to prevent overloading the DG in the process.

Approximately 1 minute after the initiating signal is received, all loads needed to recover the unit or maintain it in a safe condition are returned to service.

Ratings for Train A and Train B DGs satisfy the requirements of Regulatory Guide 1.9 (Ref. 3). The continuous service rating of each DG Catawba Units 1 and 2 B 3.8.1-2 Revision No. 6

is 7000 kW with 10% overload permissible for up to 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months in any 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months period. The ESF loads that are powered from the 4.16 kV ESF buses are listed in Reference 2.

APPLICABLE The initial conditions of DBA and transient analyses in the UFSAR, SAFETY ANALYSES Chapter 6 (Ref. 4) and Chapter 15 (Ref. 5), assume ESF systems are OPERABLE. The AC electrical power sources 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 (RCS), and containment design limits are not exceeded.

These limits are discussed in more detail in the Bases for Section 3.2, Power Distribution Limits; Section 3.4, Reactor Coolant System (RCS);

and Section 3.6, Containment Systems.

The OPERABILITY of the AC electrical power sources is consistent with the initial assumptions of the Accident analyses and is based upon meeting the design basis of the unit. This results in maintaining at least one train of the onsite or offsite AC sources OPERABLE during Accident conditions in the event of:

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

b. A worst case single failure.

The AC sources satisfy Criterion 3 of 10 CFR 50.36 (Ref. 6).

LCO Two qualified circuits between the offsite transmission network and the onsite Essential Auxiliary Power System and separate and independent DGs for each train ensure availability of the required power to shut down the reactor and maintain it in a safe shutdown condition after an anticipated operational occurrence (AOO) or a postulated DBA.

Additionally, one qualified circuit between the offsite transmission network and the opposite unit onsite Essential Auxiliary Power System when necessary to power shared systems and one opposite unit DG when necessary to power shared systems ensure availability of the required power to shut down the reactor and maintain it in a safe shutdown condition after an AOO or a postulated DBA.

Qualified offsite circuits are those that are described in the UFSAR and are part of the licensing basis for the unit.

In addition, one required automatic load sequencer per train must be OPERABLE.

Each offsite circuit must be capable of maintaining rated frequency and voltage, and accepting required loads during an accident, while connected to the ESF buses.

Catawba Units 1 and 2 B 3.8.1-3 Revision No. 6

The 4.16 kV essential system is divided into two completely redundant and independent trains designated A and B, each consisting of one 4.16 kV switchgear assembly, three 4.16 kV/600 V transformers, two 600 V load centers, and associated loads.

Normally, each Class 1E 4.16 kV switchgear is powered from its associated non-Class 1E train of the 6.9 kV Normal Auxiliary Power System as discussed in "6.9 kV Normal Auxiliary Power System" in Chapter 8 of the UFSAR (Ref. 2). Additionally, a standby source of power to each 4.16 kV essential switchgear, not required by General Design Criterion 17, is provided from the 6.9 kV system via two separate and independent 6.9/4.16 kV transformers. These transformers are shared between units and provide the capability to supply a standby source of preferred power to each unit's 4.16 kV essential switchgear from either unit's 6.9 kV system. A key interlock scheme is provided to preclude the possibility of connecting the two units together at either the 6.9 or 4.16 kV level.

Each train of the 4.16 kV Essential Auxiliary Power System is also provided with a separate and independent emergency diesel generator to supply the Class 1E loads required to safely shut down the unit following a design basis accident. Additionally, each diesel generator is capable of supplying its associated 4.16 kV blackout switchgear through a connection with the 4.16 kV essential switchgear.

Each DG must be capable of starting, accelerating to rated speed and voltage, and connecting to its respective ESF bus on detection of bus undervoltage. This will be accomplished within 11 seconds. Each DG must also be capable of accepting required loads within the assumed loading sequence intervals, and continue to operate until offsite power can be restored to the ESF buses. These capabilities are required to be met from a variety of initial conditions such as DG in standby with the engine hot and DG in standby with the engine at ambient conditions.

Additional DG capabilities must be demonstrated to meet required Surveillance, e.g., capability of the DG to revert to standby status on an ECCS signal while operating in parallel test mode.

Proper sequencing of loads, including tripping of nonessential loads, is a required function for DG OPERABILITY.

The AC sources in one train must be separate and independent (to the extent possible) of the AC sources in the other train. For the DGs, separation and independence are complete.

For the offsite AC sources, separation and independence are provided to the extent practical.

LCO 3.8.1.c and LCO 3.8.1.d both use the word necessary to clarify when and how to apply these LCOs on a per unit basis. The word necessary clarifies that the qualified offsite circuit in LCO 3.8.1.c and the one DG from the opposite unit in LCO 3.8.1.d are aligned to the Catawba Units 1 and 2 B 3.8.1-4 Revision No. 6

opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of shared systems.

LCO 3.8.1.c specifies that one qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System be OPERABLE when necessary to supply power to the shared systems. LCO 3.8.1.d specifies that one DG from the opposite unit be OPERABLE when necessary to supply power to the shared systems. The qualified circuit in LCO 3.8.1.c must be separate and independent (to the extent possible) of the qualified circuit which provides power to the other train of shared systems. These requirements, in conjunction with the requirements for the applicable unit AC electrical power sources in LCO 3.8.1.a and LCO 3.8.1.b, ensure that power is available to two trains of the shared NSWS, CRAVS, CRACWS and ABFVES.

For example, with both units in MODE 1, the normal power alignment per plant procedures with no inoperable equipment is to have the Train A shared systems powered from Unit 1 (1EMXG) and the Train B shared systems powered from Unit 2 (2EMXH). In this normal alignment, Unit 1 LCO 3.8.1.c is met by an OPERABLE 2B offsite circuit and LCO 3.8.1.d is met by an OPERABLE 2B DG. Since the 2A offsite circuit and 2A DG are not necessary to supply power to a train of shared systems in the normal power alignment, they are not Unit 1 LCO 3.8.1.c and LCO 3.8.1.d AC sources for this example. For Unit 2, LCO 3.8.1.c is met by an OPERABLE 1A offsite circuit and LCO 3.8.1.d is met by an OPERABLE 1A DG. Since the 1B offsite circuit and 1B DG are not necessary to supply power to a train of shared systems in the normal power alignment, they are not Unit 2 LCO 3.8.1.c and LCO 3.8.1.d AC sources for this example.

APPLICABILITY The AC sources and sequencers are required to be OPERABLE in MODES 1, 2, 3, and 4 to ensure that:

a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of AOOs or abnormal transients; and

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

A Note has been added taking exception to the Applicability requirements for the required AC sources in LCO 3.8.1.c and LCO 3.8.1.d provided the associated shared systems are inoperable. This exception is intended to allow declaring the shared systems supported by the opposite unit inoperable either in lieu of declaring the opposite unit AC sources inoperable, or at any time subsequent to entering ACTIONS for an inoperable opposite unit AC source.

Catawba Units 1 and 2 B 3.8.1-5 Revision No. 6

This exception is acceptable since, with the shared systems supported by the opposite unit inoperable and the associated ACTIONS entered, the opposite unit AC sources provide no additional assurance of meeting the above criteria.

The AC power requirements for MODES 5 and 6 are covered in LCO 3.8.2, "AC SourcesShutdown."

ACTIONS A Note prohibits the application of LCO 3.0.4.b to an inoperable DG.

There is an increased risk associated with entering a MODE or other specified condition in the Applicability with an inoperable DG and the provisions of LCO 3.0.4.b, which allow entry into a MODE or other specified condition in the Applicability with the LCO not met after performance of a risk assessment addressing inoperable systems and components, should not be applied in this circumstance.

When entering Required Actions for inoperable offsite circuit(s) and/or DG(s), it is also necessary to enter the applicable Required Actions of any shared systems LCOs when either normal or emergency power to shared components governed by these LCOs becomes inoperable.

These LCOs include 3.7.8, Nuclear Service Water System (NSWS);

3.7.10, Control Room Area Ventilation System (CRAVS); 3.7.11, Control Room Area Chilled Water System (CRACWS); and 3.7.12, Auxiliary Building Filtered Ventilation Exhaust System (ABFVES).

A.1 To ensure a highly reliable power source remains with one LCO 3.8.1.a offsite circuit inoperable, it is necessary to verify the OPERABILITY of the remaining required offsite circuits on a more frequent basis. Since the Required Action only specifies "perform," a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action not met.

However, if a second required circuits fails SR 3.8.1.1, the second offsite circuit is inoperable, and Condition CG, for two offsite circuits inoperable, is entered.

A.2 Required Action A.2, which only applies if the train cannot be powered from an offsite source, is intended to provide assurance that an event coincident with a single failure of the associated DG will not result in a complete loss of safety function of critical redundant required features.

These features are powered from the redundant AC electrical power train. This includes motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump is required to be considered a redundant required feature, and, therefore, required to be determined OPERABLE by this Required Action. Three independent AFW pumps are required to ensure the availability of decay heat removal capability for all events Catawba Units 1 and 2 B 3.8.1-6 Revision No. 6

accompanied by a loss of offsite power and a single failure. System design is such that the remaining OPERABLE motor driven auxiliary feedwater pump is not by itself capable of providing 100% of the auxiliary feedwater flow assumed in the safety analysis.

The Completion Time for Required Action A.2 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action, the Completion Time only begins on discovery that both:

a. The train has no offsite power supplying it loads; and

b. A required feature on the other train is inoperable.

If at any time during the existence of Condition A (one LCO 3.8.1.a offsite circuit inoperable) a redundant required feature subsequently becomes inoperable, this Completion Time begins to be tracked.

Discovering no offsite power to one train of the onsite Class 1E Electrical Power Distribution System coincident with one or more inoperable required support or supported features, or both, that are associated with the other train that has offsite power, results in starting the Completion Times for the Required Action. Twenty-four hours is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

The remaining OPERABLE offsite circuits and DGs are adequate to supply electrical power to Train A and Train B of the onsite Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the component OPERABILITY of the redundant counterpart to the inoperable required feature. Additionally, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

A.3 According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition A for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . With one offsite circuit inoperable, the reliability of the offsite system is degraded, and the potential for a loss of offsite power is increased, with attendant potential for a challenge to the unit safety systems. In this Condition, however, the remaining OPERABLE offsite circuit and DGs are adequate to supply electrical power to the onsite Class 1E Distribution System.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

The second Completion Time for Required Action A.3 establishes a limit Catawba Units 1 and 2 B 3.8.1-7 Revision No. 6

on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b. If Condition A is entered while, for instance, a LCO 3.8.1.b DG is inoperable and that DG is subsequently returned OPERABLE, the LCO may already have been not met for up to 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months s14 days. This could lead to a total of 144 hour0.00167 days 0.04 hours 2.380952e-4 weeks 5.4792e-5 months s17 days, since initial failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b, to restore the offsite circuit. At this time, a DG could again become inoperable, the circuit restored OPERABLE, and an additional 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months s14 days (for a total of 9 31 days) allowed prior to complete restoration of the LCOLCOs 3.8.1.a and 3.8.1.b. The 6 17 day Completion Time provides a limit on the time allowed in a specified condition after discovery of failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b. This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. The "AND" connector between the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months and 6 17 day Completion Times means that both Completion Times apply simultaneously, and the more restrictive Completion Time must be met.

As in Required Action A.2, the Completion Time allows for an exception to the normal "time zero" for beginning the allowed outage time "clock."

This will result in establishing the "time zero" at the time that the LCOLCO 3.8.1.a or LCO 3.8.1.b was initially not met, instead of at the time Condition A was entered.

B.1 It is required to administratively verify both opposite-unit DGs OPERABLE within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and to continue this action once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter until restoration of the required LCO 3.8.1.b DG is accomplished. This verification provides assurance that both opposite-unit DGs are capable of supplying the onsite Class 1E AC Electrical Power Distribution System.

B.12 To ensure a highly reliable power source remains with an inoperable LCO 3.8.1.b DG, it is necessary to verify the availability of the required offsite circuits on a more frequent basis. Since the Required Action only specifies "perform," a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action being not met. However, if a circuit fails to pass SR 3.8.1.1, it is inoperable. Upon offsite circuit inoperability, additional Conditions and Required Actions must then be entered.

B.23 Required Action B.2 3 is intended to provide assurance that a loss of offsite power, during the period that a LCO 3.8.1.b DG is inoperable, does not result in a complete loss of safety function of critical systems.

These features are designed with redundant safety related trains. This includes motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump is required to be considered a redundant Catawba Units 1 and 2 B 3.8.1-8 Revision No. 6

required feature, and, therefore, required to be determined OPERABLE by this Required Action. Three independent AFW pumps are required to ensure the availability of decay heat removal capability for all events accompanied by a loss of offsite power and a single failure. System design is such that the remaining OPERABLE motor driven auxiliary feedwater pump is not by itself capable of providing 100% of the auxiliary feedwater flow assumed in the safety analysis. Redundant required feature failures consist of inoperable features associated with a train, redundant to the train that has an inoperable LCO 3.8.1.b DG.

The Completion Time for Required Action B.2 3 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action, the Completion Time only begins on discovery that both:

a. An inoperable LCO 3.8.1.b DG exists; and

b. A required feature on the other train (Train A or Train B) is inoperable.

If at any time during the existence of this Condition (one LCO 3.8.1.b DG inoperable) a required feature subsequently becomes inoperable, this Completion Time would begin to be tracked.

Discovering one required LCO 3.8.1.b DG inoperable coincident with one or more inoperable required support or supported features, or both, that are associated with the OPERABLE DG, results in starting the Completion Time for the Required Action. Four hours from the discovery of these events existing concurrently is Acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

In this Condition, the remaining OPERABLE DGs and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the required feature's function may have been lost; however, function has not been lost. The 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months Completion Time takes into account the OPERABILITY of the redundant counterpart to the inoperable required feature. Additionally, the 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

B.34.1 and B.34.2 Required Action B.34.1 provides an allowance to avoid unnecessary testing of OPERABLE DG(s). If it can be determined that the cause of the inoperable DG does not exist on the OPERABLE DG, SR 3.8.1.2 does not have to be performed. If the cause of inoperability exists on other DG(s), the other DG(s) would be declared inoperable upon discovery and Condition E and/or I of LCO 3.8.1, as applicable, would be Catawba Units 1 and 2 B 3.8.1-9 Revision No. 6

entered. Once the failure is repaired, the common cause failure no longer exists, and Required Action B.34.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on the remaining DG(s), performance of SR 3.8.1.2 suffices to provide assurance of continued OPERABILITY of that DG.

In the event the inoperable DG is restored to OPERABLE status prior to completing either B.34.1 or B.34.2, the problem investigation process will continue to evaluate the common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months constraint imposed while in Condition B.

These Conditions are not required to be entered if the inoperability of the DG is due to an inoperable support system, an independently testable component, or preplanned testing or maintenance. If required, these Required Actions are to be completed regardless of when the inoperable DG is restored to OPERABLE status.

According to Generic Letter 84-15 (Ref. 8), 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is reasonable to confirm that the OPERABLE DG(s) is not affected by the same problem as the inoperable DG.

B.5 In order to extend the Completion Time for an inoperable DG from 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to 14 days, it is necessary to ensure the availability of the ESPS prior to entering the extended Completion Time of Required Action B.6 (i.e., 14 days) and every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter. The extended Completion Time of ACTION B.6 is defined as 14 days. ESPS availability requires that:

1) The load test has been performed within 30 days of entry into the extended Completion Time. The Required Action evaluation is met with an administrative verification of this prior to testing; and

2) ESPS fuel tank level is verified locally to be KRXUVXSSO\DQG

3) ESPS supporting system parameters for starting and operating are verified to be within required limits for functional availability (e.g., battery state of charge).

On discovery of an unavailable ESPS, the Completion Time for Required Action B.6 starts the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months clock.

The ESPS is not used to extend the Completion Time for more than one inoperable DG at any one time.

B.46 According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition B for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

Catawba Units 1 and 2 B 3.8.1-10 Revision No. 6

In accordance with Branch Technical Position 8-8 (Ref. 14), operation may continue in Condition B for a period that should not exceed 14 days, provided a supplemental AC power source is available.

In Condition B, the remaining OPERABLE DGs, available ESPS and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. The 72 hour14 day Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

If the ESPS is or becomes unavailable with an inoperable LCO 3.8.1.b DG, then action is required to restore the ESPS to available status or to restore the DG to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from discovery of an unavailable ESPS. However, if the ESPS unavailability occurs sometime after 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of continuous DG inoperability (i.e., after entering the extended Completion Time for an inoperable DG), then the remaining time to restore the ESPS to available status or to restore the DG to OPERABLE status is limited to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months and 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Times allow for an exception to the normal time zero for beginning the allowed outage time clock. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time only begins on discovery that both an inoperable DG exists and the ESPS is unavailable. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time only begins if the extended Completion Time for the inoperable DG has been entered and the ESPS is unavailable.

Therefore, when one LCO 3.8.1.b DG is inoperable due to either preplanned maintenance (preventive or corrective) or unplanned corrective maintenance work, the Completion Time can be extended from 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to 14 days if it is ensured that ESPS is available for backup operation.

The second fourth Completion Time for Required Action B.4 6 establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b. If Condition B is entered while, for instance, an a LCO 3.8.1.a offsite circuit is inoperable and that circuit is subsequently restored OPERABLE, the LCO may already have been not met for up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . This could lead to a total of 144 hour0.00167 days 0.04 hours 2.380952e-4 weeks 5.4792e-5 months s17 days, since initial failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b, to restore the DG. At this time, an a LCO 3.8.1.a offsite circuit could again become inoperable, the DG restored OPERABLE, and an additional 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months (for a total of 9 20 days) allowed prior to complete restoration of the LCOLCO 3.8.1.a and LCO 3.8.1.b.

The 6 17 day Completion Time provides a limit on time allowed in a specified condition after discovery of failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b. This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. The "AND" connector between the 72 hour14 day and 6 17 day Completion Times means that both Completion Times apply simultaneously, and the more restrictive Catawba Units 1 and 2 B 3.8.1-11 Revision No. 6

Completion Time must be met.

As in Required Action B.23, the Completion Time allows for an exception to the normal "time zero" for beginning the allowed time "clock." This will result in establishing the "time zero" at the time that the LCOLCO 3.8.1.a or LCO 3.8.1.b was initially not met, instead of at the time Condition B was entered.

C.1.1 and C.1.2 In Condition C with an opposite-unit DG inoperable, the remaining OPERABLE unit-specific DG and required qualified circuits are adequate to supply electrical power to the onsite Class 1E Distribution System.

According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition C for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

D.1 Pursuant to LCO 3.0.6, the Distribution System ACTIONS would not be entered even if all AC sources to it were inoperable, resulting in de-energization. Therefore, the Required Actions of Condition D are modified by a Note to indicate that when Condition D is entered with no AC source to any train, the Conditions and Required Actions for LCO 3.8.9 must be immediately entered. This allows Condition D to provide requirements for the loss of a LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. Limiting Condition for Operation 3.8.9 provides the appropriate restrictions for a de-energized train.

To ensure a highly reliable power source remains with the one required LCO 3.8.1.c offsite circuit inoperable, it is necessary to verify the OPERABILITY of the remaining required offsite circuits on a more frequent basis. Since the Required Action only specifies perform, a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action not met. However, if a second required circuit fails SR 3.8.1.1, the second offsite circuit is inoperable, and Condition A and G, as applicable, for the two offsite circuits inoperable, is entered.

D.2 Required Action D.2, which only applies if the train cannot be powered from an offsite source, is intended to provide assurance that an event coincident with a single failure of the associated DG will not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES. The Completion Time for Required Action D.2 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal time zero for beginning the allowed outage time clock. In this Catawba Units 1 and 2 B 3.8.1-12 Revision No. 6

Required Action, the Completion Time only begins on discovery that both:

a. The train has no offsite power supplying its loads: and

b. NSWS, CRAVS, CRACWS or ABFVES on the other train that has offsite power is inoperable.

If at any time during the existence of Condition D (one required LCO 3.8.1.c offsite circuit inoperable) a train of NSWS, CRAVS, CRACWS or ABFVES becomes inoperable, this Completion Time begins to be tracked.

Discovering no offsite power to one train of the onsite Class 1E Electrical Power Distribution System coincident with one train of NSWS, CRAVS, CRACWS or ABFVES that is associated with the other train that has offsite power, results in starting the Completion Times for the Required Action. Twenty-four hours is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

The remaining OPERABLE offsite circuits and DGs are adequate to supply electrical power to Train A and Train B of the onsite Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the component OPERABILITY of the redundant counterpart to the inoperable NSWS, CRAVS, CRACWS or ABFVES. Additionally, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

D.3 Consistent with the time provided in ACTION A, operation may continue in Condition D for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . With one required LCO 3.8.1.c offsite circuit inoperable, the reliability of the offsite system is degraded, and the potential for a loss of offsite power is increased, with attendant potential for a challenge to the unit safety systems. In this Condition, however, the remaining OPERABLE offsite circuits and DGs are adequate to supply electrical power to the onsite Class 1E Distribution System.

If the LCO 3.8.1.c required offsite circuit cannot be restored to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , the NSWS, CRAVS, CRACWS and ABFVES components associated with the offsite circuit must be declared inoperable. The ACTIONS associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure the appropriate actions are taken.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

E.1 Catawba Units 1 and 2 B 3.8.1-13 Revision No. 6

Pursuant to LCO 3.0.6, the Distribution System ACTIONS would not be entered even if all AC sources to it were inoperable, resulting in de-energization. Therefore, the Required Actions of Condition E are modified by a Note to indicate that when Condition E is entered with no AC source to any train, the Conditions and Required Actions for LCO 3.8.9 must be immediately entered. This allows Condition E to provide requirements for the loss of the LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. Limiting Condition for Operation 3.8.9 provides the appropriate restrictions for a de-energized train.

The 14 day Completion Time for Required Action E.5 is based on the OPERABILITY of the other three safety-related DGs and the availability of the ESPS. The ESPS is available to power the inoperable DG bus loads in the event of a station blackout or loss of offsite power event. It is required to administratively verify the three safety-related DGs OPERABLE and the ESPS available within one hour and to continue this action once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter until restoration of the required DG is accomplished. This verification provides assurance that the three safety-related DGs and the ESPS are capable of supplying the onsite Class 1E AC Electrical Power Distribution System.

E.2 To ensure a highly reliable power source remains with the one required LCO 3.8.1.d DG inoperable, it is necessary to verify the OPERABILITY of the required offsite circuits on a more frequent basis. Since the Required Action only specifies perform, a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action not met. However, if a circuit fails to pass SR 3.8.1.1, it is inoperable. Upon offsite circuit inoperability, additional Conditions and Required Actions must then be entered.

E.3 Required Action E.3 is intended to provide assurance that a loss of offsite power, during the period the LCO 3.8.1.d DG is inoperable, does not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES. The Completion Time is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal time zero for beginning the allowed outage time clock. In this Required Action, the Completion Time only begins on discovery that both:

a. An inoperable LCO 3.8.1.d DG exists; and

b. NSWS, CRAVS, CRACWS or ABFVES on the other train that has emergency power is inoperable.

If at any time during the existence of this Condition (the LCO 3.8.1.d DG inoperable) a train of NSWS, CRAVS, CRACWS or ABFVES becomes inoperable, this Completion Time begins to be tracked.

Catawba Units 1 and 2 B 3.8.1-14 Revision No. 6

Discovering the LCO 3.8.1.d DG inoperable coincident with one train of NSWS, CRAVS, CRACWS or ABFVES that is associated with the other train that has emergency power results in starting the Completion Time for the Required Action. Four hours from the discovery of these events existing concurrently is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

In this Condition, the remaining OPERABLE DGs and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the NSWS, CRAVS, CRACWS or ABFVES may have been lost; however, function has not been lost. The four hour Completion Time also takes into account the capacity and capability of the remaining NSWS, CRAVS, CRACWS and ABFVES train, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

E.4.1 and E.4.2 Required Action E.4.1 provides an allowance to avoid unnecessary testing of OPERABLE DGs. If it can be determined that the cause of the inoperable DG does not exist on the OPERABLE DG(s), SR 3.8.1.2 does not have to be performed. If the cause of inoperability exists on other DG(s), the other DG(s) would be declared inoperable upon discovery and Condition B and I of LCO 3.8.1, as applicable, would be entered. Once the failure is repaired, the common cause failure no longer exists and Required Action E.4.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on the remaining DG(s),

performance of SR 3.8.1.2 suffices to provide assurance of continued OPERABILITY of the DG(s).

In the event the inoperable DG is restored to OPERABLE status prior to completing either E.4.1 or E.4.2, the problem investigation process will continue to evaluate the common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months constraint imposed while in Condition E.

According to Generic Letter 84-15 (Ref. 8), 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is reasonable to confirm that the OPERABLE DG(s) is not affected by the same problem as the inoperable DG.

E.5 Consistent with the time provided in ACTION B, operation may continue in Condition E for a period that should not exceed 14 days. In Condition E, the remaining OPERABLE DGs, available ESPS and offsite power circuits are adequate to supply electrical power to the Class 1E Distribution System.

If the LCO 3.8.1.d DG cannot be restored to OPERABLE status within 14 Catawba Units 1 and 2 B 3.8.1-15 Revision No. 6

days, then the NSWS, CRAVS, CRACWS and ABFVES components associated with this DG must be declared inoperable. The Actions associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure the appropriate actions are taken.

The 14 day Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

F.1.1 and F.1.2 In Condition F, with an additional safety-related DG inoperable or the ESPS unavailable, the remaining OPERABLE DG and qualified circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. According to Regulatory Guide 1.93 (Ref. 7),

operation may continue in Condition F for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

F.1.3 If the LCO 3.8.1.d DG cannot be restored to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , then the NSWS, CRAVS, CRACWS and ABFVES components associated with this DG must be declared inoperable. The Required Actions associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure that the appropriate actions are taken.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

CG.1 and CG.2 Condition G is entered when both offsite circuits required by LCO 3.8.1.a are inoperable, or when the offsite circuit required by LCO 3.8.1.c and one offsite circuit required by LCO 3.8.1.a are concurrently inoperable, if the LCO 3.8.1.a offsite circuit is credited with providing power to the NSWS, CRAVS, CRACWS and ABFVES.

Required Action CG.1, which applies when two offsite circuits are inoperable, is intended to provide assurance that an event with a coincident single failure will not result in a complete loss of redundant required safety functions. The Completion Time for this failure of redundant required features is reduced to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months from that allowed for one train without offsite power (Required Action A.2). The rationale for the reduction to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is that Regulatory Guide 1.93 (Ref. 7) allows a Completion Time of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months for two required offsite circuits inoperable, based upon the assumption that two complete safety trains are OPERABLE. When a concurrent redundant required feature failure exists, this assumption is not the case, and a shorter Completion Time of Catawba Units 1 and 2 B 3.8.1-16 Revision No. 6

12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is appropriate. These features are powered from redundant AC safety trains. This includes motor driven auxiliary feedwater pumps.

Single train features, such as turbine driven auxiliary pumps, are not included in the list.

The Completion Time for Required Action CG.1 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action the Completion Time only begins on discovery that both:

a. All required offsite circuits are inoperable; and

b. A required feature is inoperable.

If at any time during the existence of Condition C G (two LCO 3.8.1.a offsite circuits inoperable or one LCO 3.8.1.a offsite circuit that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and the required LCO 3.8.1.c offsite circuit inoperable) a required feature becomes inoperable, this Completion Time begins to be tracked.

According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition C G for a period that should not exceed 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . This level of degradation means that the offsite electrical power system does not have the capability to effect a safe shutdown and to mitigate the effects of an accident; however, the onsite AC sources have not been degraded. This level of degradation generally corresponds to a total loss of the immediately accessible offsite power sources.

Because of the normally high availability of the offsite sources, this level of degradation may appear to be more severe than other combinations of two AC sources inoperable that involve one or more DGs inoperable.

However, two factors tend to decrease the severity of this level of degradation:

a. The configuration of the redundant AC electrical power system that remains available is not susceptible to a single bus or switching failure; and

b. The time required to detect and restore an unavailable offsite power source is generally much less than that required to detect and restore an unavailable onsite AC source.

With both of the required offsite circuits inoperable, sufficient onsite AC sources are available to maintain the unit in a safe shutdown condition in the event of a DBA or transient. In fact, a simultaneous loss of offsite AC sources, a LOCA, and a worst case single failure were postulated as a part of the design basis in the safety analysis. Thus, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time provides a period of time to effect restoration of one of the offsite circuits commensurate with the importance of maintaining an AC electrical power system capable of meeting its design criteria.

Catawba Units 1 and 2 B 3.8.1-17 Revision No. 6

According to Reference 6, with the available offsite AC sources, two less than required by the LCO, operation may continue for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . 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. If only one offsite source is restored within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , power operation continues in accordance with Condition A or D, as applicable.

DH.1 and DH.2 Pursuant to LCO 3.0.6, the Distribution System ACTIONS would not be entered even if all AC sources to it were inoperable, resulting in de-energization. Therefore, the Required Actions of Condition D H are modified by a Note to indicate that when Condition D H is entered with no AC source to any train, the Conditions and Required Actions for LCO 3.8.9, "Distribution SystemsOperating," must be immediately entered. This allows Condition D H to provide requirements for the loss of one offsite circuit and one DG, without regard to whether a train is de-energized. LCO 3.8.9 provides the appropriate restrictions for a de-energized train.

According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition D H for a period that should not exceed 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

In Condition DH, individual redundancy is lost in both the offsite electrical power system and the onsite AC electrical power system. Since power system redundancy is provided by two diverse sources of power, however, the reliability of the power systems in this Condition may appear higher than that in Condition C G (loss of both two required offsite circuits). This difference in reliability is offset by the susceptibility of this power system configuration to a single bus or switching failure. The 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

EI.1 With Train A and Train B DGstwo LCO 3.8.1.b DGs inoperable, there are no remaining standby AC sources to provide power to most of the ESF systems. With one LCO 3.8.1.d DG inoperable and the LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable, there are no remaining standby AC sources to the NSWS, CRAVS, CRACWS and ABFVES. Thus, with an assumed loss of offsite electrical power, insufficient standby AC sources are available to power the minimum required ESF functions. Since the offsite electrical power system is the only source of AC power for this level of degradation, the risk associated with continued operation for a very short time could be less than that associated with an immediate controlled shutdown (the immediate shutdown could cause grid instability, which could result in a total loss of AC power). Since any inadvertent generator trip could also result in a total loss of offsite AC power, however, the time allowed for continued operation is severely restricted. The intent here is to avoid the Catawba Units 1 and 2 B 3.8.1-18 Revision No. 6

risk associated with an immediate controlled shutdown and to minimize the risk associated with this level of degradation.

According to Reference 7, with both LCO 3.8.1.b DGs inoperable, or with the LCO 3.8.1.b DG that provides power to the NSWS, CRAVS, CRACWS and ABFVES and the LCO 3.8.1.d DG inoperable, operation may continue for a period that should not exceed 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months .

FJ.1 The sequencer(s) is an essential support system to both the offsite circuit and the DG associated with a given ESF bus. Furthermore, the sequencer is on the primary success path for most major AC electrically powered safety systems powered from the associated ESF bus.

Therefore, loss of an ESF bus sequencer affects every major ESF system in the train. When a sequencer is inoperable, its associated unit and train related offsite circuit and DG must also be declared inoperable and their corresponding Conditions must also be entered. The 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion Time provides a period of time to correct the problem commensurate with the importance of maintaining sequencer OPERABILITY. This time period also ensures that the probability of an accident (requiring sequencer OPERABILITY) occurring during periods when the sequencer is inoperable is minimal.

GK.1 and GK.2 If the inoperable AC electric power sources cannot be restored to OPERABLE status within the required Completion Time,If any Required Action and associated Completion Time of Conditions A, C, F, G, H, I, or J are not met, the unit must be brought to a MODE in which the LCO does not apply. Furthermore, if any Required Action and associated Completion Time of Required Actions B.2, B.3, B.4.1, B.4.2, B.6, E.2, E.3, E.4.1, E.4.2, or E.5 are not met, the unit must be brought to a MODE in which the LCO does not apply. To achieve this status, the unit must be brought to at least MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and to MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging plant systems.

HL.1 Condition H L corresponds to a level of degradation in which all redundancy in the LCO 3.8.1.a and LCO 3.8.1.b AC electrical power supplies has been lost. At this severely degraded level, any further losses in the AC electrical power system will cause a loss of function.

Therefore, no additional time is justified for continued operation. The unit is required by LCO 3.0.3 to commence a controlled shutdown.

SURVEILLANCE The AC sources are designed to permit inspection and testing of all Catawba Units 1 and 2 B 3.8.1-19 Revision No. 6

REQUIREMENTS important areas and features, especially those that have a standby function, in accordance with 10 CFR 50, Appendix A, GDC 18 (Ref. 9).

Periodic component tests are supplemented by extensive functional tests during refueling outages (under simulated accident conditions). The SRs for demonstrating the OPERABILITY of the DGs are in accordance with the recommendations of Regulatory Guide 1.9 (Ref. 3), Regulatory Guide 1.108 (Ref. 10), and Regulatory Guide 1.137 (Ref. 11), as addressed in the UFSAR.

Where the SRs discussed herein specify voltage and frequency tolerances, the following is applicable. The minimum steady state output voltage of 3950 V is 95% of the nominal 4160 V output voltage. This value allows for voltage drop to the terminals of 4000 V motors whose minimum operating voltage is specified as 90% or 3600 V. It also allows for voltage drops to motors and other equipment down through the 120 V level where minimum operating voltage is also usually specified as 90%

of name plate rating.

The specified maximum steady state output voltage of 4580 V is equal to the maximum operating voltage specified for 4000 V motors. It ensures that for a lightly loaded distribution system, the voltage at the terminals of 4000 V motors is no more than the maximum rated operating voltages.

The specified minimum and maximum frequencies of the DG are 58.8 Hz and 61.2 Hz, respectively. These values are equal to +/- 2% of the 60 Hz nominal frequency and are derived from the recommendations given in Regulatory Guide 1.9 (Ref. 3).

The SRs are modified by a Note which states that SR 3.8.1.1 through SR 3.8.1.20 are applicable to LCO 3.8.1.a and LCO 3.8.1.b AC sources. The Note also states that SR 3.8.1.21 is applicable to LCO 3.8.1.c and LCO 3.8.1.d AC sources. This Note clarifies that not all of the SRs are applicable to all the components described in the LCO.

Catawba Units 1 and 2 B 3.8.1-20 Revision No. 6

AC SourcesOperating B 3.8.1 BASES SURVEILLANCE REQUIREMENTS (continued) allow portions of the Surveillance to be performed for the purpose of reestablishing OPERABILITY (e.g. post work testing following corrective maintenance, corrective modification, deficient or incomplete surveillance testing, and other unanticipated OPERABILITY concerns) provided an assessment determines plant safety is maintained or enhanced. This assessment shall, at a minimum, consider the potential outcomes and transients associated with a failed partial Surveillance, a successful partial Surveillance, and a perturbation of the offsite or onsite system when they are tied together or operated independently for the partial Surveillance; as well as the operator procedures available to cope with these outcomes. These shall be measured against the avoided risk of a plant shutdown and startup to determine that plant safety is maintained or enhanced when portions of the Surveillance are performed in MODE 1, 2, 3, or 4. Risk insights or deterministic methods may be used for this assessment. Credit may be taken for unplanned events that satisfy this SR.

SR 3.8.1.20 This Surveillance demonstrates that the DG starting independence has not been compromised. Also, this Surveillance demonstrates that each engine can achieve proper speed within the specified time when the DGs are started simultaneously.

The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program.

This SR is modified by a Note. The reason for the Note is to minimize wear on the DG during testing. For the purpose of this testing, the DGs must be started from standby conditions, that is, with the engine coolant and oil continuously circulated and temperature maintained consistent with manufacturer recommendations.

SR 3.8.1.21 This SR lists the SRs that are applicable to LCO 3.8.1.c and LCO 3.8.1.d (SRs 3.8.1.1, 3.8.1.2, 3.8.1.4, 3.8.1.5 and 3.8.1.6). Meeting any single SR for LCO 3.8.1.c and LCO 3.8.1.d will satisfy both Unit 1 and Unit 2 requirements for that SR.

Catawba Units 1 and 2 B 3.8.1-35 Revision No. 6

AC SourcesOperating B 3.8.1 BASES REFERENCES 1. 10 CFR 50, Appendix A, GDC 17.

2. UFSAR, Chapter 8.

3. Regulatory Guide 1.9, Rev. 2, December 1979.

4. UFSAR, Chapter 6.

5. UFSAR, Chapter 15.

6. 10 CFR 50.36, Technical Specifications, (c)(2)(ii).

7. Regulatory Guide 1.93, Rev. 0, December 1974.

8. Generic Letter 84-15, "Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability," July 2, 1984.

9. 10 CFR 50, Appendix A, GDC 18.

10. Regulatory Guide 1.108, Rev. 1, August 1977 (Supplement September 1977).

11. Regulatory Guide 1.137, Rev. 1, October 1979.

12. ASME, Boiler and Pressure Vessel Code,Section XI.

13. Response to a Request for Additional Information (RAI) concerning the June 5, 2006 License Amendment Request (LAR) Applicable to Technical Specification (TS) 3.8.1, AC Sources-Operating, Surveillance Requirement (SR) 3.8.1.13, (TAC NOS. MD3217, MD3218, MD3219, and MD3220), April 4, 2007.

14. Branch Technical Position 8-8, February 2012.

Catawba Units 1 and 2 B 3.8.1-36 Revision No. 6 to RA-17-0051 Attachment 4 Revised McGuire Technical Specification Bases Marked Up Pages (For Information Only)

AC SourcesOperating B 3.8.1 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.1 AC SourcesOperating BASES BACKGROUND The unit Essential Auxiliary or Class 1E AC Electrical Power Distribution System AC sources consist of the offsite power sources (preferred power sources, normal and alternate(s)), and the onsite standby power sources (Train A and Train B diesel generators (DGs)). As required by 10 CFR 50, Appendix A, GDC 17 (Ref. 1), the design of the AC electrical power system provides independence and redundancy to ensure an available source of power to the Engineered Safety Feature (ESF) systems.

The onsite Class 1E AC Distribution System is divided into redundant load groups (trains) so that the loss of any one group does not prevent the minimum safety functions from being performed. Each train has connections to two preferred offsite power sources and a single DG.

At the 600V level of the onsite Class 1E AC Distribution System, there are two motor control centers (MCC) per train (for a total of four MCCs) that supply all of the shared systems on both units. The MCCs 1EMXG and 1EMXH supply Train A shared systems. The MCCs 2EMXG and 2EMXH supply Train B shared systems. The term shared systems is defined as the shared components of Train A or Train B of Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES). The MCCs 1EMXG and 1EMXH are normally aligned to receive power from load centers 1ELXA (1EMXH) and 1ELXC (1EMXG) but if desired or required to maintain operability of the Train A shared systems, can be swapped to receive power from load centers 2ELXA (1EMXH) and 2ELXC (1EMXG). The MCCs 2EMXG and 2EMXH are normally aligned to receive power from load centers 2ELXB (2EMXH) and 2ELXD (2EMXG) but if desired or required to maintain operability of the Train B shared systems, can be swapped to receive power from load centers 1ELXB (2EMXH) and 1ELXD (2EMXG).

There are also provisions to accommodate the connecting of the Emergency Supplemental Power Source (ESPS) to one train of either units Class 1E AC Distribution System. The ESPS consists of two 50% capacity non-safety related commercial grade DGs. Manual actions are required to align the ESPS to the station and only one of the stations four onsite Class 1E Distribution System trains can be supplied by the ESPS at any given time.

The ESPS is made available to support extended Completion Times in the event of an inoperable DG as well as a defense-in-depth source of AC power McGuire Units 1 and 2 B 3.8.1-1 Revision No. 115

BACKGROUND (continued) to mitigate a station blackout event. The ESPS would remain disconnected from the Class 1E AC Distribution System unless required for supplemental power to one of the four 4.16 kV ESF buses.

Offsite power is supplied to the unit switchyard(s) from the transmission network by two transmission lines. From the switchyard(s), two electrically and physically separated circuits provide AC power, through step down station auxiliary transformers, to the 4.16 kV ESF buses. A detailed description of the offsite power network and the circuits to the Class 1E ESF buses is found in the UFSAR, Chapter 8 (Ref. 2).

A qualified offsite circuit consists of all breakers, transformers, switches, interrupting devices, cabling, and controls required to transmit power from the offsite transmission network to the onsite Class 1E ESF bus(es).

The offsite transmission systems normally supply their respective unit's onsite power supply requirements. However, in the event that one or both buslines of a unit become unavailable, or by operational desire, it is acceptable to supply that unit's offsite to onsite power requirements by aligning the affected 4160V bus of the opposite unit via the standby transformers, SATA and SATB in accordance with Regulatory Guides 1.6 and 1.81 (Ref. 12 and 13). In this alignment, each unit's offsite transmission system could simultaneously supply its own 4160V buses and one (or both) of the buses of the other unit.

Although a single auxiliary transformer (1ATA, 1ATB, 2ATA, 2ATB) is sized to carry all of the auxiliary loads of its unit plus both trains of essential 4160V loads of the opposite unit, the LCO would not be met in this alignment due to separation criteria.

McGuire Units 1 and 2 B 3.8.1-2 Revision No. 115

AC Sources-Operating B 3.8.1 BASES BACKGROUND (continued)

Each unit's Train A and B 4160V bus must be derived from separate offsite buslinesqualified offsite circuits. The first offsite power supplyqualified offsite circuit can be derived from any of the four buslines (1A, 1B, 2A, or 2B). The second offsite power supplyqualified offsite circuit must not derive its power from the same busline qualified offsite circuit as the first. Additionally, the Train A and Train B Class 1E AC Distribution Systems providing power to the Train A and Train B shared systems must not derive their power from the same qualified offsite circuit.

Acceptable train and unit specific breaker alignment options are described below:

Unit 1 A Train

1. BL1A-1ATA-1TA-1ATC-1ETA

2. BL1B-1ATB-1TA-1ATC-1ETA

3. BL1A-1ATA-1TC-SATA-1ETA

4. BL1B-1ATB-1TC-SATA-1ETA

5. BL2A-2ATA-2TC-SATA-1ETA

6. BL2B-2ATB-2TC-SATA-1ETA Unit 1 B Train

1. BL1B-1ATB-1TD-1ATD-1ETB

2. BL1A-1ATA-1TD-1ATD-1ETB

3. BL1B-1ATB-1TB-SATB-1ETB

4. BL1A-1ATA-1TB-SATB-1ETB

5. BL2B-2ATB-2TB-SATB-1ETB

6. BL2A-2ATA-2TB-SATB-1ETB Unit 2 A Train

1. BL2A-2ATA-2TA-2ATC-2ETA

2. BL2B-2ATB-2TA-2ATC-2ETA

3. BL2A-2ATA-2TC-SATA-2ETA

4. BL2B-2ATB-2TC-SATA-2ETA

5. BL1A-1ATA-1TC-SATA-2ETA

6. BL1B-1ATB-1TC-SATA-2ETA Unit 2 B Train

1. BL2B-2ATB-2TD-2ATD-2ETB

2. BL2A-2ATA-2TD-2ATD-2ETB

3. BL2B-2ATB-2TB-SATB-2ETB

4. BL2A-2ATA-2TB-SATB-2ETB

5. BL1B-1ATB-1TB-SATB-2ETB

6. BL1A-1ATA-1TB-SATB-2ETB McGuire Units 1 and 2 B 3.8.1-3 Revision No. 115

AC Sources-Operating B 3.8.1 BASES BACKGROUND (continued)

Certain required unit loads are returned to service in a predetermined sequence in order to prevent overloading the transformer supplying offsite power to the onsite Class 1E Distribution System. Typically (via accelerated sequencing), within 1 minute after the initiating signal is received, all loads needed to recover the unit or maintain it in a safe condition are returned to service.

The onsite standby power source for each 4.16 kV ESF bus is a dedicated DG. DGs A and B are dedicated to ESF buses ETA and ETB, respectively.

A DG starts automatically on a safety injection (SI) signal (i.e., low pressurizer pressure or high containment pressure signals) or on an ESF bus degraded voltage or undervoltage signal (refer to LCO 3.3.5, "Loss of Power (LOP) Diesel Generator (DG) Start Instrumentation"). After the DG has started, it will automatically tie to its respective bus after offsite power is tripped as a consequence of ESF bus undervoltage or degraded voltage, independent of or coincident with an SI signal. The DGs will also start and operate in the standby mode without tying to the ESF bus on an SI signal alone. Following the trip of offsite power, a sequencer strips loads from the ESF bus. When the DG is tied to the ESF bus, loads are then sequentially connected to its respective ESF bus by the automatic load sequencer. The sequencing logic controls the permissive and starting signals to motor breakers to prevent overloading the DG by automatic load application.

In the event of a loss of preferred power, the ESF electrical loads are automatically connected to the DGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a Design Basis Accident (DBA) such as a loss of coolant accident (LOCA).

Certain required unit loads are returned to service in a predetermined sequence in order to prevent overloading the DG in the process.

Typically (via accelerated sequencing), within 1 minute after the initiating signal is received, all loads needed to recover the unit or maintain it in a safe condition are returned to service.

Ratings for Train A and Train B DGs satisfy the requirements of Regulatory Guide 1.9 (Ref. 3). The continuous service rating of each DG is 4000 kW with 10% overload permissible for up to 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months in any 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months period. The ESF loads that are powered from the 4.16 kV ESF buses are listed in Reference 2.

APPLICABLE The initial conditions of DBA and transient analyses in the UFSAR, SAFETY ANALYSES Chapter 6 (Ref. 4) and Chapter 15 (Ref. 5), assume ESF systems are OPERABLE. The AC electrical power sources 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 McGuire Units 1 and 2 B 3.8.1-4 Revision No. 115

AC Sources-Operating B 3.8.1 BASES APPLICABLE SAFETY ANALYSES (continued)

Coolant System (RCS), and containment design limits are not exceeded.

These limits are discussed in more detail in the Bases for Section 3.2, Power Distribution Limits; Section 3.4, Reactor Coolant System (RCS);

and Section 3.6, Containment Systems.

The OPERABILITY of the AC electrical power sources is consistent with the initial assumptions of the Accident analyses and is based upon meeting the design basis of the unit. This results in maintaining at least one train of the onsite or offsite AC sources OPERABLE during Accident conditions in the event of:

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

b. A worst case single failure.

The AC sources satisfy Criterion 3 of 10 CFR 50.36 (Ref. 6).

LCO Two qualified circuits between the offsite transmission network and the onsite Class 1E Electrical Power System and separate and independent DGs for each train ensure availability of the required power to shut down the reactor and maintain it in a safe shutdown condition after an anticipated operational occurrence (AOO) or a postulated DBA.

Additionally, one qualified circuit between the offsite transmission network and the opposite unit onsite Essential Auxiliary Power System when necessary to power shared systems and one opposite unit DG when necessary to power shared systems ensure availability of the required power to shut down the reactor and maintain it in a safe shutdown condition after an AOO or a postulated DBA.

Qualified offsite circuits are those that are described in the UFSAR and are part of the licensing basis for the unit.

In addition, one required automatic load sequencer per train must be OPERABLE.

Each offsite circuit must be capable of maintaining rated frequency and voltage, and accepting required loads during an accident, while connected to the ESF buses.

The 4.16 kV essential system is divided into two completely redundant and independent trains designated A and B, each consisting of one 4.16 kV switchgear assembly, two 4.16 kV/600 V load centers, and associated loads.

McGuire Units 1 and 2 B 3.8.1-5 Revision No. 115

AC Sources-Operating B 3.8.1 BASES LCO (continued)

Normally, each Class 1E 4.16 kV switchgear is powered from its associated non-Class 1E train of the 6.9 kV Normal Auxiliary Power System as discussed in "6.9 kV Normal Auxiliary Power System" in Chapter 8 of the UFSAR (Ref. 2). Additionally, an alternate source of power to each 4.16 kV essential switchgear is provided from the 6.9 kV system via a separate and independent 6.9/4.16 kV transformer. Two transformers are shared between units and provide the capability to supply an alternate source of power to each unit's 4.16 kV essential switchgear from either unit's 6.9 kV system. A key interlock scheme is provided to preclude the possibility of connecting the two units together at either the 6.9 or 4.16 kV level.

Each train of the 4.16 kV Essential Auxiliary Power System is also provided with a separate and independent emergency diesel generator to supply the Class 1E loads required to safely shut down the unit following a design basis accident.

Each DG must be capable of starting, accelerating to rated speed and voltage, and connecting to its respective ESF bus on detection of bus undervoltage. This will be accomplished within 11 seconds. Each DG must also be capable of accepting required loads within the assumed loading sequence intervals, and continue to operate until offsite power can be restored to the ESF buses. These capabilities are required to be met from a variety of initial conditions such as DG in standby with the engine hot and DG in standby with the engine at ambient conditions.

Additional DG capabilities must be demonstrated to meet required Surveillance, e.g., capability of the DG to revert to standby status on an ECCS signal while operating in parallel test mode.

Proper sequencing of loads is a function of Sequencer OPERABILITY.

Proper load shedding is a function of DG OPERABILITY. Proper tripping of non-essential loads is a function of AC Bus OPERABILITY (Condition A of Technical Specification 3.8.9).

The AC sources in one train must be separate and independent (to the extent possible) of the AC sources in the other train. For the DGs, separation and independence are complete.

LCO 3.8.1.c and LCO 3.8.1.d both use the word necessary to clarify when and how to apply these LCOs on a per unit basis. The word necessary clarifies that the qualified offsite circuit in LCO 3.8.1.c and the one DG from the opposite unit in LCO 3.8.1.d are aligned to the opposite unit Onsite Essential Auxiliary Power System that is supplying power to a train of shared systems.

LCO 3.8.1.c specifies that one qualified circuit between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System be OPERABLE when necessary to supply power to the McGuire Units 1 and 2 B 3.8.1-6 Revision No. 115

AC Sources-Operating B 3.8.1 BASES LCO (continued) shared systems. LCO 3.8.1.d specifies that one DG from the opposite unit be OPERABLE when necessary to supply power to the shared systems. The qualified circuit in LCO 3.8.1.c must be separate and independent (to the extent possible) of the qualified circuit which provides power to the other train of shared systems. These requirements, in conjunction with the requirements for the applicable unit AC electrical power sources in LCO 3.8.1.a and LCO 3.8.1.b, ensure that power is available to two trains of the shared NSWS, CRAVS, CRACWS and ABFVES.

For example, with both units in MODE 1, the normal power alignment per plant procedures with no inoperable equipment is to have the Train A shared systems powered from Unit 1 (1EMXG and 1EMXH) and the Train B shared systems powered from Unit 2 (2EMXG and 2EMXH). In this normal alignment, Unit 1 LCO 3.8.1.c is met by an OPERABLE 2B offsite circuit and LCO 3.8.1.d is met by an OPERABLE 2B DG. Since the 2A offsite circuit and 2A DG are not necessary to supply power to a train of shared systems in the normal power alignment, they are not Unit 1 LCO 3.8.1.c and LCO 3.8.1.d AC sources for this example. For Unit 2, LCO 3.8.1.c is met by an OPERABLE 1A offsite circuit and LCO 3.8.1.d is met by an OPERABLE 1A DG. Since the 1B offsite circuit and 1B DG are not necessary to supply power to a train of shared systems in the normal power alignment, they are not Unit 2 LCO 3.8.1.c and LCO 3.8.1.d AC sources for this example.

Both normal and emergency power must be OPERABLE for a shared component to be OPERABLE. If normal or emergency power supplying a shared component becomes inoperable, then the Required Actions of the affected shared component LCO must be entered independently for each unit that is in the MODE of applicability of the shared component LCO.

The shared component LCOs are:

3.7.7 - Nuclear Service Water System (NSWS),

3.7.9 - Control Room Area Ventilation System (CRAVS),

3.7.10 - Control Room Area Chilled Water System (CRACWS), and 3.7.11 - Auxiliary Building Filtered Ventilation Exhaust System (ABFVES).

McGuire Units 1 and 2 B 3.8.1-7 Revision No. 115

AC Sources-Operating B 3.8.1 BASES APPLICABILITY The AC sources and sequencers are required to be OPERABLE in MODES 1, 2, 3, and 4 to ensure that:

a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of AOOs or abnormal transients; and

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

A Note has been added taking exception to the Applicability requirements for the required AC sources in LCO 3.8.1.c and LCO 3.8.1.d provided the associated shared systems are inoperable. This exception is intended to allow declaring the shared systems supported by the opposite unit inoperable either in lieu of declaring the opposite unit AC sources inoperable, or at any time subsequent to entering ACTIONS for an inoperable opposite unit AC source.

This exception is acceptable since, with the shared systems supported by the opposite unit inoperable and the associated ACTIONS entered, the opposite unit AC sources provide no additional assurance of meeting the above criteria.

The AC power requirements for MODES 5 and 6 are covered in LCO 3.8.2, "AC SourcesShutdown."

ACTIONS A Note prohibits the application of LCO 3.0.4.b to an inoperable DG.

There is an increased risk associated with entering a MODE or other specified condition in the Applicability with an inoperable DG and the provisions of LCO 3.0.4.b, which allow entry into a MODE or other specified condition in the Applicability with the LCO not met after performance of a risk assessment addressing inoperable systems and components, should not be applied in this circumstance.

A.1 To ensure a highly reliable power source remains with one LCO 3.8.1.a offsite circuit inoperable, it is necessary to verify the OPERABILITY of the remaining required offsite circuits on a more frequent basis. Since the Required Action only specifies "perform," a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action not met.

However, if a second required circuit fails SR 3.8.1.1, the second offsite McGuire Units 1 and 2 B 3.8.1-8 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued) circuit is inoperable, and Condition CG, for two offsite circuits inoperable, is entered.

A.2 Required Action A.2, which only applies if the train cannot be powered from an offsite source, is intended to provide assurance that an event coincident with a single failure of the associated DG will not result in a complete loss of safety function of critical redundant required features. These features are powered from the redundant AC electrical power train. This includes motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump is required to be considered a redundant required feature, and, therefore, required to be determined OPERABLE by this Required Action. Three independent AFW pumps are required to ensure the availability of decay heat removal capability for all events accompanied by a loss of offsite power and a single failure. System design is such that the remaining OPERABLE motor driven auxiliary feedwater pump is not by itself capable of providing 100% of the auxiliary feedwater flow assumed in the safety analysis.

The Completion Time for Required Action A.2 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action, the Completion Time only begins on discovery that both:

a. The train has no offsite power supplying its loads; and

b. A required feature on the other train is inoperable.

If at any time during the existence of Condition A (one LCO 3.8.1.a offsite circuit inoperable) a redundant required feature subsequently becomes inoperable, this Completion Time begins to be tracked.

Discovering no offsite power to one train of the onsite Class 1E Electrical Power Distribution System coincident with one or more inoperable required support or supported features, or both, that are associated with the other train that has offsite power, results in starting the Completion Times for the Required Action. Twenty-four hours is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

The remaining OPERABLE offsite circuits and DGs are adequate to supply electrical power to Train A and Train B of the onsite Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the component OPERABILITY of the redundant counterpart to the inoperable required feature. Additionally, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the McGuire Units 1 and 2 B 3.8.1-9 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued) capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

A.3 According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition A for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . With one offsite circuit inoperable, the reliability of the offsite system is degraded, and the potential for a loss of offsite power is increased, with attendant potential for a challenge to the unit safety systems. In this Condition, however, the remaining OPERABLE offsite circuit and DGs are adequate to supply electrical power to the onsite Class 1E Distribution System.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

The second Completion Time for Required Action A.3 establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b. If Condition A is entered while, for instance, a LCO 3.8.1.b DG is inoperable and that DG is subsequently returned OPERABLE, the LCO may already have been not met for up to 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months s14 days. This could lead to a total of 144 hour0.00167 days 0.04 hours 2.380952e-4 weeks 5.4792e-5 months s17 days, since initial failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b, to restore the offsite circuit. At this time, a DG could again become inoperable, the circuit restored OPERABLE, and an additional 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months s14 days (for a total of 9 31 days) allowed prior to complete restoration of the LCOLCOs 3.8.1.a and 3.8.1.b. The 6 17 day Completion Time provides a limit on the time allowed in a specified condition after discovery of failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b. This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. The "AND" connector between the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months and 6 17 day Completion Times means that both Completion Times apply simultaneously, and the more restrictive Completion Time must be met.

As in Required Action A.2, the Completion Time allows for an exception to the normal "time zero" for beginning the allowed outage time "clock."

This will result in establishing the "time zero" at the time that the LCOLCO 3.8.1.a or LCO 3.8.1.b was initially not met, instead of at the time Condition A was entered.

B.1 It is required to administratively verify the LCO 3.8.1.d DG OPERABLE within one hour and to continue this action once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter McGuire Units 1 and 2 B 3.8.1-10 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued) until restoration of the required LCO 3.8.1.b DG is accomplished. This verification provides assurance that the LCO 3.8.1.d DG is capable of supplying the onsite Class 1E AC Electrical Power Distribution System.

B.12 To ensure a highly reliable power source remains with an inoperable LCO 3.8.1.b DG, it is necessary to verify the availability of the required offsite circuits on a more frequent basis. Since the Required Action only specifies "perform," a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action being not met. However, if a circuit fails to pass SR 3.8.1.1, it is inoperable. Upon offsite circuit inoperability, additional Conditions and Required Actions must then be entered.

B.23 Required Action B.2 3 is intended to provide assurance that a loss of offsite power, during the period that a LCO 3.8.1.b DG is inoperable, does not result in a complete loss of safety function of critical systems. These features are designed with redundant safety related trains. This includes motor driven auxiliary feedwater pumps. The turbine driven auxiliary feedwater pump is required to be considered a redundant required feature, and, therefore, required to be determined OPERABLE by this Required Action. Three independent AFW pumps are required to ensure the availability of decay heat removal capability for all events accompanied by a loss of offsite power and a single failure. System design is such that the remaining OPERABLE motor driven auxiliary feedwater pump is not by itself capable of providing 100% of the auxiliary feedwater flow assumed in the safety analysis. Redundant required feature failures consist of inoperable features associated with a train, redundant to the train that has an inoperable LCO 3.8.1.b DG.

The Completion Time for Required Action B.2 3 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action, the Completion Time only begins on discovery that both:

a. An inoperable LCO 3.8.1.b DG exists; and

b. A required feature on the other train (Train A or Train B) is inoperable.

McGuire Units 1 and 2 B 3.8.1-11 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued)

If at any time during the existence of this Condition (one LCO 3.8.1.b DG inoperable) a required feature subsequently becomes inoperable, this Completion Time would begin to be tracked.

Discovering one required LCO 3.8.1.b DG inoperable coincident with one or more inoperable required support or supported features, or both, that are associated with the OPERABLE DG, results in starting the Completion Time for the Required Action. Four hours from the discovery of these events existing concurrently is Acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

In this Condition, the remaining OPERABLE DGs and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the required feature's function may have been lost; however, function has not been lost. The 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months Completion Time takes into account the OPERABILITY of the redundant counterpart to the inoperable required feature. Additionally, the 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

B.34.1 and B.34.2 Required Action B.34.1 provides an allowance to avoid unnecessary testing of OPERABLE DG(s). If it can be determined that the cause of the inoperable DG does not exist on the OPERABLE DG, SR 3.8.1.2 does not have to be performed. If the cause of inoperability exists on other DG(s), the other DG(s) would be declared inoperable upon discovery and Condition E and/or I of LCO 3.8.1, as applicable, would be entered. Once the failure is repaired, the common cause failure no longer exists, and Required Action B.34.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on the remaining DG(s),

performance of SR 3.8.1.2 suffices to provide assurance of continued OPERABILITY of that DG.

In the event the inoperable DG is restored to OPERABLE status prior to completing either B.34.1 or B.34.2, the problem investigation process will continue to evaluate the common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months constraint imposed while in Condition B.

These Conditions are not required to be entered if the inoperability of the DG is due to an inoperable support system, an independently testable component, or preplanned testing or maintenance. If required, these McGuire Units 1 and 2 B 3.8.1-12 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued)

Required Actions are to be completed regardless of when the inoperable DG is restored to OPERABLE status.

According to Generic Letter 84-15 (Ref. 8), 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is reasonable to confirm that the OPERABLE DG(s) is not affected by the same problem as the inoperable DG.

B.5 In order to extend the Completion Time for an inoperable DG from 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to 14 days, it is necessary to ensure the availability of the ESPS prior to entering the extended Completion Time of Required Action B.6 (i.e., 14 days) and every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter. The extended Completion Time of ACTION B.6 is defined as 14 days. ESPS availability requires that:

1) The load test has been performed within 30 days of entry into the extended Completion Time. The Required Action evaluation is met with an administrative verification of this prior to testing; and

2) ESPS fuel tank level is verified locally to be 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months supply; and

3) ESPS supporting system parameters for starting and operating are verified to be within required limits for functional availability (e.g., battery state of charge).

On discovery of an unavailable ESPS, the Completion Time for Required Action B.6 starts the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months clock.

The ESPS is not used to extend the Completion Time for more than one inoperable DG at any one time.

B.46 According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition B for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

In accordance with Branch Technical Position 8-8 (Ref. 14), operation may continue in Condition B for a period that should not exceed 14 days, provided a supplemental AC power source is available.

In Condition B, the remaining OPERABLE DGs, available ESPS and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. The 72 hour14 day Completion Time takes into account the capacity and capability of the remaining AC sources, a McGuire Units 1 and 2 B 3.8.1-13 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued) reasonable time for repairs, and the low probability of a DBA occurring during this period.

If the ESPS is or becomes unavailable with an inoperable LCO 3.8.1.b DG, then action is required to restore the ESPS to available status or to restore the DG to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months from discovery of an unavailable ESPS. However, if the ESPS unavailability occurs sometime after 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of continuous DG inoperability (i.e., after entering the extended Completion Time for an inoperable DG), then the remaining time to restore the ESPS to available status or to restore the DG to OPERABLE status is limited to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months and 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Times allow for an exception to the normal time zero for beginning the allowed outage time clock. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time only begins on discovery that both an inoperable DG exists and the ESPS is unavailable. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time only begins if the extended Completion Time for the inoperable DG has been entered and the ESPS is unavailable.

Therefore, when one LCO 3.8.1.b DG is inoperable due to either preplanned maintenance (preventive or corrective) or unplanned corrective maintenance work, the Completion Time can be extended from 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to 14 days if it is ensured that ESPS is available for backup operation.

The second fourth Completion Time for Required Action B.4 6 establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b. If Condition B is entered while, for instance, an a LCO 3.8.1.a offsite circuit is inoperable and that circuit is subsequently restored OPERABLE, the LCO may already have been not met for up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . This could lead to a total of 144 hour0.00167 days 0.04 hours 2.380952e-4 weeks 5.4792e-5 months s17 days, since initial failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b, to restore the DG. At this time, an a LCO 3.8.1.a offsite circuit could again become inoperable, the DG restored OPERABLE, and an additional 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months (for a total of 9 20 days) allowed prior to complete restoration of the LCOLCO 3.8.1.a and LCO 3.8.1.b. The 6 17 day Completion Time provides a limit on time allowed in a specified condition after discovery of failure to meet the LCOLCO 3.8.1.a or LCO 3.8.1.b.

This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. The "AND" connector between the 72 hour14 day and 6 17 day Completion Times means that both Completion Times apply simultaneously, and the more restrictive Completion Time must be met.

As in Required Action B.23, the Completion Time allows for an exception to the normal "time zero" for beginning the allowed time "clock." This will McGuire Units 1 and 2 B 3.8.1-14 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued) result in establishing the "time zero" at the time that the LCOLCO 3.8.1.a or LCO 3.8.1.b was initially not met, instead of at the time Condition B was entered.

C.1.1 and C.1.2 In Condition C with a LCO 3.8.1.d DG inoperable, the remaining OPERABLE unit-specific DG and required qualified circuits are adequate to supply electrical power to the onsite Class 1E Distribution System.

According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition C for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs and the low probability of a DBA occurring during this period.

D.1 Pursuant to LCO 3.0.6, the Distribution System ACTIONS would not be entered even if all AC sources to it were inoperable, resulting in de-energization. Therefore, the Required Actions of Condition D are modified by a Note to indicate that when Condition D is entered with no AC source to any train, the Conditions and Required Actions for LCO 3.8.9 must be immediately entered. This allows Condition D to provide requirements for the loss of a LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. Limiting Condition for Operation 3.8.9 provides the appropriate restrictions for a de-energized train.

To ensure a highly reliable power source remains with the one required LCO 3.8.1.c offsite circuit inoperable, it is necessary to verify the OPERABILITY of the remaining required offsite circuits on a more frequent basis. Since the Required Action only specifies perform, a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action not met. However, if a second required circuit fails SR 3.8.1.1, the second offsite circuit is inoperable, and Condition A and G, as applicable, for the two offsite circuits inoperable, is entered.

D.2 Required Action D.2, which only applies if the train cannot be powered from an offsite source, is intended to provide assurance that an event coincident with a single failure of the associated DG will not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES. The Completion Time for Required Action D.2 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the McGuire Units 1 and 2 B 3.8.1-15 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued) normal time zero for beginning the allowed outage time clock. In this Required Action, the Completion Time only begins on discovery that both:

a. The train has no offsite power supplying its loads; and

b. NSWS, CRAVS, CRACWS or ABFVES on the other train that has offsite power is inoperable.

If at any time during the existence of Condition D (one required LCO 3.8.1.c offsite circuit inoperable) a train of NSWS, CRAVS, CRACWS or ABFVES becomes inoperable, this Completion Time begins to be tracked.

Discovering no offsite power to one train of the onsite Class 1E Electrical Power Distribution System coincident with one train of NSWS, CRAVS, CRACWS or ABFVES that is associated with the other train that has offsite power, results in starting the Completion Time for the Required Action. Twenty-four hours is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

The remaining OPERABLE offsite circuits and DGs are adequate to supply electrical power to Train A and Train B of the onsite Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the component OPERABILITY of the redundant counterpart to the inoperable NSWS, CRAVS, CRACWS or ABFVES. Additionally, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

D.3 Consistent with the time provided in ACTION A, operation may continue in Condition D for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . With one required LCO 3.8.1.c offsite circuit inoperable, the reliability of the offsite system is degraded, and the potential for a loss of offsite power is increased, with attendant potential for a challenge to the unit safety systems. In this Condition, however, the remaining OPERABLE offsite circuits and DGs are adequate to supply electrical power to the onsite Class 1E Distribution System.

If the LCO 3.8.1.c required offsite circuit cannot be restored to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , the NSWS, CRAVS, CRACWS and ABFVES components associated with the offsite circuit must be declared inoperable. The ACTIONS associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure the appropriate actions are taken.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and McGuire Units 1 and 2 B 3.8.1-16 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued) capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

E.1 Pursuant to LCO 3.0.6, the Distribution System ACTIONS would not be entered even if all AC sources to it were inoperable, resulting in de-energization. Therefore, the Required Actions of Condition E are modified by a Note to indicate that when Condition E is entered with no AC source to any train, the Conditions and Required Actions for LCO 3.8.9 must be immediately entered. This allows Condition E to provide requirements for the loss of the LCO 3.8.1.c offsite circuit and LCO 3.8.1.d DG without regard to whether a train is de-energized. Limiting Condition for Operation 3.8.9 provides the appropriate restrictions for a de-energized train.

The 14 day Completion Time for Required Action E.5 is based on the OPERABILITY of both LCO 3.8.1.b safety-related DGs and the availability of the ESPS. The ESPS is available to power the inoperable DG bus loads in the event of a station blackout or loss of offsite power event. It is required to administratively verify the LCO 3.8.1.b safety-related DGs OPERABLE and the ESPS available within one hour and to continue this action once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter until restoration of the required DG is accomplished. This verification provides assurance that the LCO 3.8.1.b safety-related DGs and the ESPS are capable of supplying the onsite Class 1E AC Electrical Power Distribution System.

E.2 To ensure a highly reliable power source remains with the one required LCO 3.8.1.d DG inoperable, it is necessary to verify the OPERABILITY of the required offsite circuits on a more frequent basis. Since the Required Action only specifies perform, a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action not met. However, if a circuit fails to pass SR 3.8.1.1, it is inoperable. Upon offsite circuit inoperability, additional Conditions and Required Actions must then be entered.

E.3 Required Action E.3 is intended to provide assurance that a loss of offsite power, during the period the LCO 3.8.1.d DG is inoperable, does not result in a complete loss of safety function for the NSWS, CRAVS, CRACWS or the ABFVES. The Completion Time is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for exception to the normal time zero for beginning the allowed outage time clock. In this Required Action, the Completion Time only begins on discovery that both:

McGuire Units 1 and 2 B 3.8.1-17 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued)

a. An inoperable LCO 3.8.1.d DG exists; and

b. NSWS, CRAVS, CRACWS or ABFVES on the other train that has emergency power is inoperable.

If at any time during the existence of this Condition (the LCO 3.8.1.d DG inoperable) a train of NSWS, CRAVS, CRACWS or ABFVES becomes inoperable, this Completion Time begins to be tracked.

Discovering the LCO 3.8.1.d DG inoperable coincident with one train of NSWS, CRAVS, CRACWS or ABFVES that is associated with the other train that has emergency power results in starting the Completion Time for the Required Action. Four hours from the discovery of these events existing concurrently is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.

In this Condition, the remaining OPERABLE DGs and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the NSWS, CRAVS, CRACWS or ABFVES may have been lost; however, function has not been lost. The four hour Completion Time also takes into account the capacity and capability of the remaining NSWS, CRAVS, CRACWS and ABFVES train, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

E.4.1 and E.4.2 Required Action E.4.1 provides an allowance to avoid unnecessary testing of OPERABLE DGs. If it can be determined that the cause of the inoperable DG does not exist on the OPERABLE DG(s), SR 3.8.1.2 does not have to be performed. If the cause of inoperability exists on other DG(s), the other DG(s) would be declared inoperable upon discovery and Condition B and I of LCO 3.8.1, as applicable, would be entered. Once the failure is repaired, the common cause failure no longer exists and Required Action E.4.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on the remaining DG(s),

performance of SR 3.8.1.2 suffices to provide assurance of continued OPERABILITY of the DG(s).

In the event the inoperable DG is restored to OPERABLE status prior to completing either E.4.1 or E.4.2, the problem investigation process will continue to evaluate the common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months constraint imposed while in Condition E.

McGuire Units 1 and 2 B 3.8.1-18 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued)

According to Generic Letter 84-15 (Ref. 8), 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is reasonable to confirm that the OPERABLE DG(s) is not affected by the same problem as the inoperable DG.

E.5 Consistent with the time provided in ACTION B, operation may continue in Condition E for a period that should not exceed 14 days. In Condition E, the remaining OPERABLE DGs, available ESPS and offsite power circuits are adequate to supply electrical power to the Class 1E Distribution System.

If the LCO 3.8.1.d DG cannot be restored to OPERABLE status within 14 days, then the NSWS, CRAVS, CRACWS and ABFVES components associated with this DG must be declared inoperable. The Actions associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure the appropriate actions are taken.

The 14 day Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

F.1.1 and F.1.2 In Condition F, with an additional LCO 3.8.1.b safety-related DG inoperable or the ESPS unavailable, the remaining OPERABLE LCO 3.8.1.b DG and qualified circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition F for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

F.1.3 If the LCO 3.8.1.d DG cannot be restored to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , then the NSWS, CRAVS, CRACWS and ABFVES components associated with this DG must be declared inoperable. The Required Actions associated with the NSWS, CRAVS, CRACWS and ABFVES will ensure that the appropriate actions are taken.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.

McGuire Units 1 and 2 B 3.8.1-19 Revision No. 115

AC Sources-Operating B 3.8.1 BASES ACTIONS (continued)

CG.1 and CG.2 Condition G is entered when both offsite circuits required by LCO 3.8.1.a are inoperable, or when the offsite circuit required by LCO 3.8.1.c and one offsite circuit required by LCO 3.8.1.a are concurrently inoperable, if the LCO 3.8.1.a offsite circuit is credited with providing power to the NSWS, CRAVS, CRACWS and ABFVES.

Required Action CG.1, which applies when two offsite circuits are inoperable, is intended to provide assurance that an event with a coincident single failure will not result in a complete loss of redundant required safety functions. The Completion Time for this failure of redundant required features is reduced to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months from that allowed for one train without offsite power (Required Action A.2). The rationale for the reduction to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is that Regulatory Guide 1.93 (Ref. 7) allows a Completion Time of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months for two required offsite circuits inoperable, based upon the assumption that two complete safety trains are OPERABLE. When a concurrent redundant required feature failure exists, this assumption is not the case, and a shorter Completion Time of 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is appropriate. These features are powered from redundant AC safety trains. This includes motor driven auxiliary feedwater pumps.

Single train features, such as turbine driven auxiliary pumps, are not included in the list.

The Completion Time for Required Action CG.1 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action the Completion Time only begins on discovery that both:

a. All required offsite circuits are inoperable; and

b. A required feature is inoperable.

If at any time during the existence of Condition C G (two LCO 3.8.1.a offsite circuits inoperable or one LCO 3.8.1.a offsite circuit that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and the required LCO 3.8.1.c offsite circuit inoperable) a required feature becomes inoperable, this Completion Time begins to be tracked.

According to Regulatory Guide 1.93 (Ref. 7), operation may continue in Condition C G for a period that should not exceed 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . This level of degradation means that the offsite electrical power system does not have the capability to effect a safe shutdown and to mitigate the effects of an accident; however, the onsite AC sources have not been degraded. This level of degradation generally corresponds to a total loss of the immediately accessible offsite power sources.

McGuire Units 1 and 2 B 3.8.1-20 Revision No. 115