Text

Submittal of Exigent License Amendment Request (LAR)18-001, Revision to Technical Specification 3.8.4, DC Sources - Operating, Condition B
	ML18250A186
Person / Time
Site:	Comanche Peak
Issue date:	09/05/2018
From:	Thomas McCool; Vistra Energy
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	CP-201800112, TXX-18010
	Download: ML18250A186 (48)
	v • d • e

CP-201800112 TXX-18010 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 ENERGY

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.._, energy Luminant 9/5/2018

SUBJECT:

Comanche Peak Nuclear Power Plant (CPNPP)

Docket No. 50-445 Submittal of Exigent License Amendmen_t Request (LAR)18-001, Thomas P. McCool

?ite Vice President Luminant P.O. Box 1002 6322 North FM 56 Glen Rose, TX 76043 o 254.897.6042 Ref 10 CFR 50.90 10 CFR 50.91{a)(6) 10 CFR 50.91{b)

Revision to Technical Specification 3.8.4, "DC Sources - Operating," Condition B

Dear Sir or Mc;1dam:

Pursuant to 10 CFR 50.90, Vistra Operations Company LLC {Vistra OpCo) hereby *requests a license amendment to revise Unit 1 and 2 "Technical Specifications {TS). The proposed one-time change will revise TS 3.8.4, "DC Sources - Operating," to modify TS Actions for one inoperabl'e battery. The revised REQUIRED ACTIONS provide 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months to replace a jumpered battery cell to restore margin in safety related batteries BT1ED2 (cell 27) and BT1ED4 (cell 41) {18 hours per cell, not at the same time). This change is necessary to permit a net increase in plant safety and reliability without inducing transient risk. The inoperable DC power source would be available for all but approximately 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months of the requested 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months COMPLETION TIME {CT) and effectively serves as its own backup power source. The approximately 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months of unavailability is equivalent to the current 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months CT of TS 3.8.4 REQUIRED ACTION B.1. This change applies to Comanche Peak Nuclear Power Plant {CPNPP) Unit 1. License Amendment Request (LAR)18-001 is a one-time change to replace one cell each in batteries BT1ED2 and BT1ED4 during Unit 1 Cycle 20.

The Enclosure provides a description and assessment of proposed changes. Attachment 1 contains a list of inspections, compensatory measures, and conditions. Attachment 2 contains a regulatory commitment associated with requested change. Attachment 3 provides existing TS pages marked to show proposed changes. provides existing TS Bases pages marked to show proposed changes for information only. provides revised (clean) TS pages. Attachment 6 provides a response to items identified in NRC Summary of April 10, 2018, Public Teleconference {ADAMS No. ML1806A009). Attachment 7 provides supporting figures for LAR 18-001. Attachment 8 provides supporting tables for LAR 18-001. Attachments 9 and 10 provide supplemental risk information.

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TXX-18010 Page 2 of 2 Approval of the proposed amendment is requested by October 3, 2018, to support replacement of a battery cell 27 in battery BT1ED2 and cell 41 in battery BT1ED4 during Unit 1 Cycle 20. Vistra OpCo will implement the amendment immediately upon NRC approval.

In accordance with 10CFR50.91(b), Vistra OpCo is providing the State ofTexas with a copy of this proposed amendment.

This communication contains a commitment regarding CPNPP Units 1 and 2 as described in Attachment 2.

Should you have any questions, please contact Carl B. Corbin at (254) 897-0121.

I state under penalty of perjury that the foregoing is true and correct.

Executed on September 5, 2018.

Enclosure 0 c-Sincerely, Th-:11::;

Description and Assessment of the Proposed Changes List of Inspections, Compensatory Measures, and Conditions List of Regulatory Commitments Existing TS Pages Marked to Show the Proposed Changes Existing TS Bases Pages Marked to Show the Proposed Changes [For Information Only]

Revised (Clean) TS Pages CPNPP Response to NRC Summary of April 10, 2018, Public Teleconference Supporting Figures for LAR 18-001 Supporting Tables for LAR 18-001 Baseline Average Annual CDF/LERF ICCDP and ICLERP for One-Time Technical Specification Change Kriss Kennedy, Region IV Mark Haire, Region IV Margaret Watford O'Banion, NRR Resident Inspectors, Comanche Peak Mr. Robert Free Environmental Monitori.ng & Emergency Response Manager Texas Department of State Health Services Mail Code 1986 P. 0. Box 149347 Austin TX, 78714-9347

Enclosure to TXX-18010 Page 1 of 21 Table of Contents 1.0

SUMMARY

DESCRIPTION................................................ _........................................................................... 2 2.0, DETAILED DESCRIPTION......................................... '... :.............................................................................. 2 2.1 System Design and Operation............................................................................................................... 2 2.2 Current Technical Specification Requirements..................................... :............................................... 3 2.3 Reason for Proposed Change..................,............................................................................................. 3 2.4 Description of Proposed Change........................................................................................................... 5

3.0 TECHNICAL EVALUATION

........................................................................................................................... 5 3.1 Deterministic Evaluation........................................................................................................................ 5 3.1.1 Battery Sizing Analysis...................................................................................................................... 5 3.1.2 Battery Cell Replacement Discussion............................................................................................... 5 3.1.4 Defense in Depth Considerations......................................... *.**.......................................................... 6 3.1.5 Evaluation of Battery Voltage Margins.............................................................................................. 9 3.1.6 Battery Operational and Maintenance History................................................................................... 9 3.1.7 Conformance with NUREG-0800 and NUREG-0800 BTP 8-8 Recommendations......................... 10 3.2 Supplemental Risk Information............................................................................................................ 12 3.2.1 Probabilistic Risk Assessment Capability and Insights................... :............................................... 12 3.2.2 Avoidance of Risk Significant Plant Configurations......................................................................... 12 3.2.3 Risk Informed Configuration Management......................,............................................................... 14 3.3 Conclusions.......................................................................................................................... :.............. 16

4.0 REGULATORY EVALUATION

.................................................................................................................... 17 4.1 Applicable Regulatory Requirements.................................................................................................. 17 4.2 Precedent............................................................................................................................................ 18 4.3 No Significant Hazards Consideration Determination.,.......................................... :............................ 18 4.4 Conclusions......................................................................................................................................... 19

5.0 ENVIRONMENTAL CONSIDERATION

S.......................................... :................... :..................................... 20

6.0 REFERENCES

............................................................................................................................................ 20 7.0 CHRONOLOGICAL OVERVIEW OF LAR 18-001 *.************************************************************************************* 21 ATTACHMENTS

1.

List of Inspections, Compensatory Measures and Conditions

2.

List of Regulatory Commitments

3.

Existing Technical Specification Pages Marked to Show Proposed Changes

4.

Existing Technical Specification Bases Pages Marked to Show the Proposed Changes [For Information Only]

5.

Revised (Clean TS Pages)

6.

CPNPP Response to NRC Summary of April 10, 2018, Public Teleconference

7.

Supporting Figures for LAR 18-001

8.

Supporting Tables for LAR 18-001

9.

Baseline Average Annual CDF/LERF

10. ICCbP and ICLERP for One-Time Technical Specifi~ation Change

Enclosure to TXX-18010 Page 2 of 21 1.0

SUMMARY

DESCRIPTION Proposed License Amendment Request (LAR)18-001 is to revise Technical Specifications (TS} 3.8.4, "DC Sources - Operating" CONDITION B, for Comanche Peak Nuclear Power Plant (CPNPP) Units 1 and 2 (Reference 6.1 ).

Vistra Operations Company LLC (Vistra OpCo) is requesting this one-time change for safety related batteries BT1 ED2 and BT1 ED4 during Unit 1 Cycle 20. New REQUIRED ACTION 8.2 provides an 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months COMPLETION TIME (CT) to replace cell 27 in battery BT1 ED2 and 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT to replace cell 41 in battery BT1 ED4 (not at the same time). These cells are currently jumpered and their replacement will regain margin in batteries BT1 ED2 and BT1 ED4. Replacement of the jumpered battery cells will restore thl9 ability to jumper an additional cell in each battery if needed prior to complete battery cell replacement.

This one-time change applies to CPNPP Unit 1 only.

No changes to the CPNPP Final Safety Analysis Report (Reference 6.2) are anticipated as a result of this Lic~nse Amendment Request (LAR)18-001.

On April 10, 2018, a teleconference was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Vistra Operations Company, LLC (Vistra OpCo, the licensee). The purpose of the meeting was to discuss Vistra OpCo's proposed change to TS 3.8.4, "DC Sources -- Operating," for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2 (CPNPP). In advance of the meeting, the Vistra OpCo provided presentation slides (ADAMS Accession No. ML18095A171 ). On April 6, 2018, prior to the meeting, the NRC transmitted topics of discussion (ADAMS Accession No. ML180968451) to Vistra OpCo generated from the presentation slides. On April 18, 2018, the NRC transmitted a summary of the April 10, 2018, meeting to Vistra OpCo (ADAMS Accession No. ML18106A009). Attachment 6 addresses NRC items from the April 18, 2018; summary of meeting on April 10, 2018, and identifies differences between the changes proposed in April 2018 and those requested in this Enclosure.

Section 7.0 provides a chronological overview of LAR 18-001.

2.0 DETAILED DESCRIPTION 2.1 System Design and Operation The station DC systems supply power for plant instrumentation and control under all MODES of plant operation. The safety related Class 1 E 125 VDC electrical power-system consists of two independent and redundant subsystems (Train A and Train B) (See Figure 1 in Attachment 7). The Class'1E 125 VDC batteries of each subsystem (train) are separately housed in ventilated rooms apart from their chargers and distribution centers (See Figure 2 in Attachment 7). Each subsystem is located in an area separated physically and electrically from the other subsystem to ensure that a single failure in one subsystem does not cause a failure in the redundant subsystem. There is no sharing between redundant Class 1 E subsystems, such as batteries, battery chargers, or distribution panels.

There are two 100% 300 amp capacity battery chargers per battery. Normally one charger for each battery is in operation and the other is in standby. Each battery charger is sized to supply the combined steady-state loads while recharging the battery from the design minimum charge state to the fully charged state under all MODES of plant operation.

Each Class 1 E DC bus can be energized either by a battery or by one of two battery chargers or combination of battery and battery charger. During normal operation, the 125 VDC bus is powered from the battery charger and the battery is on float charge. In case of a loss of normal power to the battery charger, the DC bus is automatically powered from the battery. The Class 1 E 125 battery VDC system supplies power to Class 1 E loads without interruption during normal operations or design basis accident (DBA) conditions.

Enclosure to TXX-18010 Page 3 of 21 Each Train of Class 1*E 125 VDC electrical system includes two 125 VDC batteries. When batteries are supplying DC loads, Train A loads are fed from batteries BT1 ED1 and BT1 ED3. Train B loads are fed from batteries BT1 ED2 and BT1 ED4.

Each battery has adequate capacity to meet its duty cycle requirements. The batteries are sized to meet the duty cycle requirements at end of battery life with a capacity of 80% of nameplate rating. The battery design also includes additional capacity above that required by the design duty cycle to allow for battery room temperature variations. During duty cycle the batteries maintain a minimum voltage of 105 VDC or greater providing adequate voltage for operation of all required loads considering the circuit voltage drop from battery to load.

The battery cells are of lead-calcium type with a nominal specific gravity of 1.215. This specific gravity corresponds to an open circuit battery voltage of approximately 2.065 volts per cell (VPC). The open circuit voltage is the voltage maintained when there is no charging or discharging. Once fully charged with cell float voltage of 2.07 VPC, the battery cell will maintain its capacity for 30 days without further charging per manufacturer's instructions. The battery float charge voltage limit is established as 2.13 VDC per cell, which corresponds to a total minimum float voltage output of 128 volts for a 60 cell battery.

Optimal long term performance however, is obtained by maintaining a float voltage 2.20 to 2.25 VPC.

This provides adequate margin over rated potential, which limits the formation of lead sulfate and self-discharge. The nominal float voltage of 2.20 to 2.25 VPC corresponds to a total float voltage output of 132 to 135 V for a 60 cell battery.

2.2 Current Technical Specification Requirements TS 3.8.4, "DC Sources - Operating; CONDITION B, provides REQUIRED ACTION B.1 that allows 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months to restore one or two inoperable batteries on one train. The affected DC Bus(es) are supplied by their associated battery charger(s). Loss of the AC bus supporting the associated battery charger(s) will result in the battery supplying power to that train. The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months limit allows restoration of an inoperable battery given that the majority of the conditions that lead to battery inoperability are identified in Technical Specifications 3.8.4 "DC Sources - Operating", 3.8.5 "DC Sources - Shutdown", and 3.8.6 "Battery Parameters," together with additional specific COMPLETION TIMES. If the inoperable train is not restored within the 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months COMPLETION TIME and the plant is in MODES 1, 2, 3, or 4, the plant is required to be in MODE 3 in 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months (TS 3.8.4 REQUIRED ACTION D.1) and MODE 5 in 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (TS 3.8.4 REQUIRED ACTION D.2).

2.3 Reason for Proposed Change The safety related 125 VDC batteries are lead-calcium type consisting of 60 cells mounted in clear plastic containers with lid covers. Batteries BT1 ED2 and BT1 ED4 were last replaced in 1999 with a service life of 20 years. Batteries BT1 ED2 and BT1 ED4 are OPERABLE but nearing their 20-year nominal service life.

A long range schedule for battery replacement is provided as Table 3 of Attachment 8. See Section 3.1.5 for a discussion of battery voltage margins.

Battery Cell Cracking In November 2017 battery cell jar lid cracking was discovered. The cracking has been evaluated by the vendor and is a known industry phenomenon associated with nodular corrosion.

On November 8, 2017, battery BT1 ED4 was declared inoperable in accordance with Technical Specification 3.8.4, CONDITION B, "One or two batteries on one train inoperable" to allow jumpering of cell 41 in battery BT1 ED4. Cell 41 had failed due to a crack in the jar 1 cell with electrolyte leakage cin the floor. A jumper was placed across cell 41 to restore battery BT1 ED4 operability.

On July 2, 2018, battery BT1 ED2 was declared inoperable in accordance with Technical Specification 3.8.4, CONDITION B, "One or two batteries on one train inoperable" to allow jumpering of cell 27 in battery BT1 ED2. Cell 27 was degraded with a crack in the jar cell. A jumper was placed across cell 27 to restore battery BT1 ED2 operability.

Enclosure to TXX-18010 Page 4 of 21 Batteries BT1 ED2 and BT1 ED4 are the oldest batteries and thus have a greater potential for additional cell jar cracking. These batteries (all cells) are scheduled for replacement in the next Unit 1 refueling outage (see Table 3 of Attachment 8).

I The TS requirement to enter LCO 3.8.4, CONDITION B if "One or two batteries on one train inoperable;"

REQUIRED ACTION 8.1 restore affected battery(ies) to OPERABLE status within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months does not allow adequate time to replace a battery cell.

With the potential for additional failed battery cells in BT1 ED2 and BT1 ED4 and in the absence of approval of the requested LAR 18-001, after the current 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months completion time, actions must be taken to place Unit 1 in MODE 3 in 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . The transition from MODE 1 to MODE 3 presents a real, but as yet unquantifiable, level of increased risk. From a risk perspective it is undesirable to place Unit 1 into MODE 3 unnecessarily. With the AC and DC distribution systems OPERABLE, with the exception of the affected battery, an extension of the 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months completion time is warranted.

This one-time extension to the COMPLETION TIME for an inoperable battery is requested for batteries BT1 ED2 and BT1 ED4 (not at the same time) to provide additional time to replace battery cell 27 in BT1 ED2 and cell 41 in BT1 ED4.

Exigent Circumstances Within several months, CPNPP Unit 1 experienced a single cell cracking failure / degradation on each of two redundant 125 VDC DC batteries feeding B train 125 VDC electrical power. In each case prompt short-term corrective actions were taken to jumper the affected cell within the time permitted in the action statements of TS 3.8.4. Longer term corrective action in the form of battery replacements are planned.

This TS amendment would enable CPNPP to proactively replace both of the jumpered cells promptly (not at the same time) and thus avoid the need for either an unnecessary plant transient or requesting regulatory relief in the form of a Notice of Enforcement Discretion (NOED) or emergency technical specification amendment. In the event of an unanticipated second cell failure on either of these B train 125 VDC batteries, CPNPP would be forced to consider jumpering a second cell, if technically feasible, or shutting down the plant and imposing the associated transient, for approximately 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months for replacemefnt of the failed cell. Avoidance of an unnecessary shutdown of CPNPP Unit 1 also will limit potential impact on electrical grid stability during the remainder of Cycle 20. In the event of extreme heat and or severe weather (e.g., tornado warning) coupled with an unplanned shutdown of CPNPP Unit 1 due to a failed battery (i.e., BT1 ED2 or BT1 ED4), the grid stability could be challenged with the loss of a large base load planf Vistra OpCo initiated dialog with the NRC on a technical specification change process following the November 2017 cell failure and is making a good faith effort to submit this license'amendment request in a timely manner following the July 2018 failure. Vistra OpCo has communicated with the NRC Staff regarding this request. Accordingly, Vistra OpCo requests this amendment be processed under exigent circumstances pursuant to 10 CFR 50.91 (a)(6) to avoid a potential shutdown in accordance with TS 3.8.4 REQUIRED ACTIONS D.1 and D.2 at the expiration of REQUIRED ACTION 8.1 COMPLETION TIME of 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months .

Consistent with the Statement of Considerations accompanying issuance of 10 CFR 50.91 (a)(6), the circumstances here result in "a net increase in safety or reliability" (51 Federal Register 7744, 7756 (Mar.

6, 1986). Staff implementing guidance expresses a preference for a license amendn,ent, if possible over NOED, where possible. See Inspection Manual Chapter 410, Section 6.03. In this case, the proposed exigent license amendment process appropriately balances opportunity to improve public safety and reliability with public participation in the NRC's technical specification change process.

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Enclosure to TXX-18010 Page 5 of 21 2.4 Description of Proposed,Change Proposed LAR 18-001 would revise the REQUIRED ACTION and C,OMPLETION TIME of TS LCO 3.8.4 CONDITION B. Currently, CPNPP is required to: 8.1 Restore affected battery(ies) to OPERABLE status within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months (see Attachment 3 for marked up TS pages).

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The proposed change to the'TS would add one new REQUIRED ACTION and associated COMPLETION TIME, and a new NOTE (new items shown in italics):

8.1 Restore affected battery(ies) to OPERABLE status within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , OR B.2 Restore affected battery(ies),to OPERABLE status in 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months NOTE: REQUIRED ACTION 8.2 is applicable on a 'one-time basis to replace cell 27 in battery BT1ED2 and ce/141 in battery BT1ED4 during Unit 1 Cycle 20 (not aUhe same time). ff the second battery on the same train becomes inoperable, immediately initiatE;, Required Actions 0. 1 ood02 "For information only," Attachment 4 provides Technical Specification Bases 3.8.4 (Reference 6.2) pages

marked up to show the corresponding proposed Bases changes for the new REQUIRED ACTION 8.2, associated COMPLETION TIME, an~ the associated new NOTE.

3.0 TECHNICAL EVALUATION

3.1 Deterministic Evaluation 3.1.1 Battery Sizing Analysis All Class 1 E batteries are designed to provide adequate voltage considering the voltage drop from battery to load. Batteries BT1 ED3 and BT1 ED4, during their duty cycle, with steady state loads only, maintain a minimum voltage of 111.9 volts. Momentary load demands during the first and last minute of duty cycle of

batteries BT1 ED1 and BT1 ED2 result *in a larger voltage drop for battery to load circuits. This requires higher battery voltage to provide adequate voltage at the loads. Safety related Class 1 E 125 VDC batteries, during duty cycle, maintain a voltage of greater than 105 volts to provide adequate voltage for operation of all required loads. In accordance with ECA-0.0A, "Loss of All AC Power" (Reference 6.31),

the 105 VDC ensures a sufficient DC voltage is available to flash the diesel generator field and to operate the associated output breaker for the diesel generator.

3.1.2 Battery Cell Replacement Discussion

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Battery BT1 ED2 and BT1 ED4 each consists of 60 series connected single cells. Each battery is mounted on two steel supported racks. Figure 2 of Attachment 7 shows the plan view of the typical layout of the batteries.. Figure 3 of Attachment 7 shows a partial picture of a typical battery room. Racks are of the single row, two~tier design with 15 cells on the bottom and 15 cells on the top with the cells connected in series.

Bypassing or replacing a cell requires disconnecting the affected battery from the associated vital bus which, while in MODES 1-4 makes the battery inoperable, and requires entry into TS 3.8.4, CONDITION B. The replacement cells are sized in accordance with the current licensing basis.

Replacement of a battery cell will require partial disassembly of the seismically qualified rack assembly, installation of rigging, removal of unaffected cell(s) to gain access, removal of cell connectors, removal of the affected cell, installation of the new cell and reassembly of the previously removed cells (including connectors and seismic supports).

The replacement cells and supporting materials are staged and the replacement cells are maintained on FLOAT charge per IEEE-450-1995 requirements (Reference 6.4).

Enclosure to TXX-18010

Page 6 of 21 After reassembly of the battery, Technical Specification (Reference 6.1) SURVEILLANCE REQUIREMENTS ( SR) 3.8.4.1, SR 3.8.6.1, and Digital Low Resistance Ohmmeter (DLRO) inspection will be performed to confirm operability. Maintenance performs a DLRO inspection of the installed inter-cell connections and documents the as-left conditions per procedure MSE-P1-5003 (Reference 6.5):

j The estimated time for replacing currently jumpered cell 27 in battery BT1 ED2 is 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months (same estimated time for cell 41 in battery BT1 ED4). Table 1 of Attachment 8 provides a detailed time line of activities for the 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months estimate. Cells 27 and 41 will NOT be replaced at the same time. Even though the affected battery is inoperable due to the 'disassembly of seismic bracing, the battery will remain connected and available for approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months of the requested 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months COMPLETION TIME. For the planned activity, unavailability is limited to approximately 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and is equivalent to the existing 2.

hour COMPLETION TIME for TS 3.8.4 REQUIRED ACTION B.1.

A complete list of inspections, compensatory measures, and conditions are provided in Attachment 1 and regulatory commitment 5644411 is described in Attachment 2.

3.1.3 Compliance yvith current Regulations This LAR itself does not propose to deviate from existing regulatory requirements.

Compliance with existing regulations is maintained by the proposed one-time change to the plant's Technical Specification requirements. Additional details are provided in the Regulatory Evaluation Section 4.1 of this LAR.

3.1.4 Defense in Depth Considerations

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This request adds one new REQUIRED ACTION B.2, new NOTE, and associated COMPLETION TIME (CT) of 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months to TS 3.8.4 CONDITION B. The purpose of the new 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT is to allow sufficient time to complete planned corrective maintenance to avoid an unnecessary plant shutdown. The extension*of the CT has no impact on!the*current safety analysis because the remaining OPERABLE batteries are still available to perform their safety functions while in this TS action. The current 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months CT limit of REQUIRED ACTION B.1 is established with the TS Basis that allows sufficient time to effect restoration.

for the majority of conditions that lead to battery inoperability; the requested extension of the COMPLETION TIME is within the range previously granted at McGuire Nuclear Station (Reference 6.13) and does not significantly increase risk. For the planned activity, unavailability is limited to approximately Zhours, similar to the existing CT; for the remainder of the extension CT the battery is available, notwithstanding the vulnerability to a s.eismic event. The difference in the current TS versus the proposed extension lies in the added risk due to the extension of the CT evaluated in Section 3.2, "Supplemental Risk Information". The requested CT extension does not affect time for functional recovery, nor does it change probabilities for an initiating event, successful mitigative action, or required operator actions as )

assumed in the PRA.,

The basis untjerlying successful safety function of the DC electrical power subsystem remains unchanged with an extension of the battery CT. Each DC electrical power subsystem consists of one battery and two

dedicated*battery chargers for-each battery and the corresponding control equipment and the interconnecting cabling supplying power to the associated bus.es. The subsystems 'are required to be OPERABLE to ensure the availability of the required power to shut down the reactor and n:iaintain it in a safe condition after a postulated design basis accident (OBA). Loss of any one DC electrical power subsystem does not prevent the safety function from being performed. Because of this design feature, there is no loss in core damage prevention, containment failure prevention or consequence mitigation.

The remainder of the DC electrical power system is still able to perform its safety function as designed.

The plant design will not be modified with the proposed extension of the CT. All safety systems will still perform their design functions, and there will be no reliance on additional systems, procedures, or operator actions.

System redundancy, independence, and diversity are maintained commensurate with the expected frequency and consequences of challenges to the system.

Enclosure to TXX-18010 Page 7 of 21 TS 3.8.9, Distribution Systems - Operating A single DC electrical power distribution subsystem is capable of supporting the minimum safety functions necessary to shut down the reactor and maintain it in a safe shutdown condition, assuming no single failure. OPERABLE DC electrical power distribution subsystems require the associated busses to be energized to their proper voltage from either the associated battery or charger.

Design Basis Accident (OBA) (with no Loss of Offsite Power)

The opposite Train of DC power remains available during the extended COMPLETION TIME. Risk reduction measures are discussed in Sections 3.1.4, 3.1. 7, and 3.2.2 and captured as a commitment in to minimize potential failure of the opposite train.

Loss of Offsite Power (LOOP)

In the event of a Loss of Offsite Power (LOOP), the opposite Train of DC power would be available to start its Emergency Diesel Generator. Risk reduction measures are implemented as commitments to minimize potential for LOOP and failure of the opposite Train. The measures are discussed in Sections 3.1.4, 3.1.7, and 3.2.2 and captured as a commitment in Attachment 2.

Maintenance Surveillances Maintenance performs weekly, monthly, and quarterly Technical Specification Surveillances on Class 1 E station batteries per MSE-S0-5000, "Class 1 E Station Batteries Weekly-Monthly-Quarterly Tests" (Reference 6.6)

Weekly Inspection Total battery terminal voltage greater than or equal to 128 Volts (minimum established float voltage) (TS SR 3.8.4.1)

Monthly Inspection Battery float current less than or equal to 2 amps (TS SR 3.8.6.1)

Quarterly Inspections Verify each battery pilot cell voltage is greater than or equal to 2.07 volts (TS SR 3.8.6.2)

Verify each battery pilot cell temperature is greater than or equal to minimum established design limits (TS SR 3.8.6.4)

Verify each battery connected cell electrolyte level is greater than or equal to minimum established design limits (TS SR 3.8.6.3)

Verify each battery connected cell voltage is greater than or equal to 2.07 volts (TS SR 3.8.6.5)

IEEE 450-1995 Quarterly Inspections Electrolyte level on all cells is above the top of the plates.

Battery float voltage greater than or equal to 128 volts.

Gel.I float voltage greater than or equal to 2.13 volts.

Measurements for designated Pilot Cells:

Float voltage greater than or equal to 2.13 volts.

Corrected specific gravity greater than or equal to 1.195.

Measure ambient temperature near center of battery room.

Ventilation system is OPERABLE All cells and battery racks inspected for general appearance and cleanliness.

All cells inspected for cracks and leakage of electrolyte including post seals (if cracks or leaks exist then System Engineering is notified)

Battery is inspected for evidence of corrosion at terminals, connectors or racks.

Anti-corrosion grease applied to terminal connections.

Battery room inspected for cleanliness.

Enclosure to TXX-18010 Page 8 of 21 Battery Charger voltage and current n;,easured and recorded Operations Surveillance/ Inspections.

Shiftly Surveillance (OPT-102A-7) (Refere.nce 6.7)

Operations performs Shiftly Surveillance of Train A and B battery rooms to verify area temperature per Technical Requirements Manual Surveillance (TRS) 13. 7.36.1 (Reference 6.2).

Shiftly Tours/ Inspection (OWl-104-17) (Reference 6.8) Operations.inspection guidelines for batteries include the following:

1 Proper electrolyte level.

\\

Cell integrity - no leakage.

Cell exterior cleanliness.

Proper room ventilation.

No foreign objects on cells.

Corrosion of terminals' or connectors.

No unauthorized hotwork around the cells.

Enhanced monitoring / inspections*

In response to the recently discovered lid cracking, Engineering has implemerted a weekly walk down for all Class 1 E batteries that have a condition adverse to quality (CAQ) documented in a condition report (CR). Engineering performs a walk down to evaluate every cell in each battery string that has a CAQ. In conjunction with Engineering walk downs, Engineering and Maintenance pecsonnel m~nitor existing battery condition and evaluate conditions for any new battery issues during walk downs. Observations identified during the walk downs are entered into the corrective action program (CAP). If a new indication is found, Engineering or Maintenance notifies Operations, then initiates a condition report.

Preplanning / Staging of spare battery cell

The activities to replace the jumpered battery cells have been preplanned and materials pre-staged as described in Section 3.1.2.

Fire Protection Program Considerations There are two impacts of this proposed activity on the CPNPP Fire Protection Program. The first is the impact.due to the physical work itself. This work is known, understood, and the maintenance activity will have the necessary fire protection considerations included as r~quired by station procedures. For the maintenance activity itself, no new requirements are introduced beyond those implemented for routine activities.

The second impact is on the Fire Safe Shutdown Analysis (FSSA). The analysis assumes that there is a Loss of Offsite Power (LOOP) in conjunction with a fire and any equipment requiring power can be fed

\\

from onsite power sources. The Class* 1 E DC system on the affected train will still be available as long as there is no LOOP. In the event of a fire in conjunction with a LOOP the ability to achieve Safe Shutdown, for a fire in any fire area crediting that train of power, is compromised. This is true for any maintenance activities that potentially affect FSSA components such as the battery maintenance discussed here.

I CPNPP addresses the risk associated with performing maintenance on FSSA credited components in accordance with NEI guidance. Site Procedure STl-604.05, On-Line Fire Risk Management, (Reference 6.10), delineates the application of Fire Risk to the maintenance process and identifies the subject components and requirements to determine and specify.compensatory measures (Risk Mitigative Actions

- RMAs) when maintenance is being performed on affected FSSA equipment. When one of the required active components is unavailable, actions are imposed to reduce the station risk by enhancing one or more of the other: facets of the Fire Protection Program Defense in Depth philosophy.

Enclosure to TXX-18010 Page 9 of 21 At CPNPP the usual practice is to reduce the likelihood of a fire through a series of administrative controls and limitations that significantly reduce the potential for a fire in the subject locations. These

administrative.controls include fire watches, limitations on Hot Work, and limitations on introduction of transient combustibles.

The station batteries at CPNPP are credited by the FSSA to provide 1 E DC power. If there is no LOOP, the 1 E DC distribution system will function as required and there is no impact on the FSSA. If there is a LOOP postulated in conjunction with a fire, or if the fire causes a LOOP as a direct consequence of the fire, the unavailability of the battery will affect the timing of starting and loading of the affected Emergency

' Diesel Generator. If the FSSA is crediting the same train for the shutdown path for a fire in given fire area, the ability to.achieve and maintain safe shutdown may be compromised.

CPNPP will implement the,risk mitigating measures that are specified for addressing impactof maintenance 9n FSSA credited equipment due to the battery CT extension. -

When either battery BT1 ED2 or BT1 ED4 is inoperable in accordance with the one-time action requested, the following administrative controls and protective measures will be implemented for fire areas and fire zones of the affected Unit and Train of the inoperable battery prior to entry into the proposed18-hour COMPLETION TIME of TS 3.8.4 REQUIRED ACTION B.2:

Provide an hourly roving fire watch in the Fire Areas of Concern, Susperid performance of any ongoing "Hot Work" and prohibit the start of any new "Hot Work," in the r

j Fire Areas of Concern, Control the introduction of any new transient combustibles, or addition to transient combustibles

. already authorized to be in the Fire Areas of Concern Additional measures related to protection of the offsite power feeds from fire (not required for FSSA, rather based on risk insights) are discussed in Section 3.2 below.

A compl~te list of inspections, compensatory measures, and conditions are provided in Attachment 1 and regulatory commitment 5644411 is described in Attachment 2.

3.1.5

Evaluation of Battery Voltage Margins The proposed CT extension maintains sufficient safety margins because the redundant OPERABLE Class 1 E DC batteries will be capable of performing the necessary safety functions associated with the accident analysis. Therefore, the safety margins of the plant are not significantly affected by the extended CT.

All DC loads are considered energized for battery sizing and battery voltage evaluations. This provides an I

inherent conservatism in battery design. Batteries arecsized for end of life capacity and battery room temperature that can occur as a result of station blackout. This conservative approach in battery sizing assures that battery voltage is equal to or greater than the voltage required for the battery to perform its function.

Safety related battery calculations have been revised to address a condition identified by NRG Component Design Bases Inspection.Report (IR) 2013007 (Reference q.3).

Volt~ge margin for class 1 E batteries during the battery duty cycle is provided in Table 2 of Attachment 8.

3.1.6 Battery Operational and Maintenance History As noted in the battery Vendor Technical Manual, the battery cells are warranted for 20 years. As such, CPNPP battery cell replacement frequency has been based on the vendor recommendation.

The operational and maintenance history of.the currently installed safety related batteries is provided in Table 3 of Attachment 8.

Enclosure to TXX-18010 Page 10 of 21 3.1.7 Conformance with NUREG-0800 and NUREG-0800 BTP 8-8 Recommendations CPNPP conforms to the required GDCs and guidance of RGs, identified in NUREG-0800 (Reference 6.17) for review of Safety related 125 VDC systems:

CPNPP has reviewed NUREG-0800 Branch Technical Position (BTP) 8-8, "Onsite and Offisite Power Sources Allowed Outage Time Extensions" (Reference 6.18). The purpose of this BTP is to provide guidance from a deterministic perspective for developing and reviewing license amendment requests for one-time or permanent TS COMPLETION TIME extensions for EDGs and offsite power sources from the current TS COMPLETION TIME up to 14 days to perform online maintenance.

Even though LAR 18-001 'is not requesting an extension for EOG COMPLETION TIME, the guidance and recommendations of BTP 8-8 were addressed as noted below:

A supplemental power source should be available as a backup to the inoperable EOG or offsite power source, to maintain the defense-in-depth design philosophy of the electrical system to meet its intended safety function. The supplemental source must have capacity to bring a unit to safe shutdown (cold shutdown) in case of a loss of offsite power (LOOP) concurrent with a single failure during plant operation (Mode 1).

If there is a Loss of Offsite Power (LOOP) the unavailability of the safety related Class 1 E 125 VDC power could preclude the starting of the Emergency Diesel Generator of the same train.

Risk reduction measures are implemented as a commitment to minimize potential for LOOP and failure of the opposite Train. The measures are discussed in Sections 3.1.4, 3.1.7, and 3.2 and captured as a commitment in Attachment 2.

The new proposed REQUIRED ACTION B.2 for TS 3.8.4 includes an 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months COMPLETION TIME (CT) to replace a cell in batteries BT1 ED2 and BT1 ED4. The 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT is based on the replacement activities discussed in Section 2.4 of the Enclosure to TXX-18010 (with some margin) and in Table 1 of Attachment 8.

Even though the affected battery is inoperable due to the disassembly of seismic bracing, it will be available for approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months of the requested 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months COMPLETION TIME. In effect, the affected battery is acting as its own temp\\)rary supplemental backup power source.

This is similar to the supplemental backup power source utilized by McGuire in 2014 (Reference 6.13).

Other options were considered such as location of a full size temporary battery located nearby in a seismic, category 1 structure, non-seismic category 1 structure, or use of flex equipment. However, these options introduced other complications such as train related cable separation challenges, cable length challenges, ventilation availability, security interface, and fire protection challenges, i.e., potential impact on other protected safety related SSCs due to a lack of fire barriers.

For seismic events, CPNPP is considered to be in an area of low seismicity. The frequency of a seismic occurrence over the 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT is considered small and when considering that a train of safety related equipment would remain available for approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months of the 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT, the overall likelihood of a seismic event occurring during the CT can be considered small.

Enclosure to TXX-18010 Page 11 of 21 The extended AOT will be used no more than once in a 24-month period (or refueling interval) on a per diesel basis to perform EOG maintenance activities, or any major maintenance on offsite

-power transformer and bus.

The proposed TS 3.8.4 REQUIRED ACTION 8.2 would only be used once for each identifi_ed battery during Unit 1 Cycle 20.

The preplanned maintenance will not be scheduled if severe weather conditions are anticipated.

Battery cell replacement will not be scheduled if severe weather conditions are anticipated.

If a Severe Thunderstorm Warning or Tornado Warning is issued per ABN 907 (Reference 6.19) after entry into TS 3.8.4 proposed REQUIRED ACTJON 8.2, then exit TS 3.8.4 proposed REQUIRED ACTION 8.2 and enter TS 3.8.4 REQUIRED ACTION D.1 (Be in MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months ) and TS 3.8.4 REQUIRED ACTION D.2 (Be in MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months ).

Once the applicable severe weather warning is cancelled and plant system statuses are verified, TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 will be exited and TS 3.8.4 proposed REQUIRED ACTION 8.2 will be re-entered and battery cell replacement will continue until completed or 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months from initial entry into TS 3.8.4 proposed REQUIRED ACTION 8.2.

For example:

TS 3.8.4 proposed REQUIRED ACTION 8.2 is entered and battery cell replacement begins.

One hour after entering TS 3.8.4 proposed REQUIRED ACTION 8.2 a Tornado Warning is issued for Somervell County, the county where Comanche Peak is located.

At that one-hour point TS 3.8.4 proposed REQUIRED ACTION 8.2 is exited and TS *.

3.8.4 REQUIRED ACTIONs D.1 and D.2 are entered.

One hour after exit from TS 3.8.4 proposed REQUIRED ACTION 8.2 and entry into TS 3.8.4 REQUIRED ACTIONs D.1 and D.2, the Tornado Warning for Somervell County is cancelled and forecasts predict no further severe weather.

TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 are exited and TS 3.8.4 proposed REQUIRED ACTION 8.2 is re-entered with 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months remaining to complete battery cell replacement.

The system load dispatcher will be contacted once per day to ensure no significant grid perturbations (high grid loading unable to withstand a single contingency of line or generation outage) are expected during the extended AOT.

Prior to entry into TS 3.8.4 REQUIRED ACTION 8.2, CPNPP will contact the Transmission Grid Controller (TGM) to ensure:

o The local grid. is stable and no anticipated challenges have been identified Prior to entry into TS 3.8.4 REQUIRED ACTION 8.2, CPNPP will verify the following items and every 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months thereafter. If any item is not met, CPNPP will exit TS 3.8.4 REQUIRED ACTION 8.2 and enter TS 3.8.4 REQUIRED ACTIONS D.1 and D.2:

a.

Both offsite sources available as determined by performance of OPT-215-1, "Offsite Transmission Network Operability Data Sheet" (Reference 6.9)

b.

Affected 6.9kV bus steady state frequency is 59.5-60.5hz (Reference 6.32)

c.

The Turbine Driven Auxiliary Feedwater Pump (TDAFW) is operable per TS 3.7.5, "Auxiliary Feedwater (AFW) System"

d.

The plant is not operating under an ACTION statement for an inoperable offsite AC power source or the opposite train Emergency Die~el Generator

Enclosure to TXX-18010 Page 12 of 21 Similar to the example described in severe weather above, if TS 3.8.4 REQUIRED ACTIONS D.1 and D.2 are entered due to an item (a, b, c, or d) above not being met and the items are subsequently met, then TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 will be exited and TS 3.8.4 proposed REQUIRED ACTION 8.2 will be re-entered and battery cell replacement will continue until completed or 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months from initial entry into TS 3.8.4 proposed REQUIRED ACTION 8.2.

Component testing or maintenance of safety systems and important non-safety equipment in the offsite power systems that can increase the likelihood of a plant transient (unit trip) or LOOP will be avoided. In addition, no discretionary switchyard maintenance will be performed.

See commitment in Attachment 2.

TS required systems, subsystems, trains, components, and devices that depend on the remaining power sources will be verified to be operable and positive measures will be provided to preclude subsequent testing or maintenance activities on these systems, subsystems, trains, components, and devices.

See commitment in Attachment 2.

Steam-driven emergency feed water pump(s) in case of PWR units, and Reactor Core Isolation Cooling and High Pressure Coolant Injection systems in case of BWR units, will be controlled as "protected equipment."

See commitment in Attachment 2.

A complete list of inspections, compensatory measures, and conditions are provided in Attachment 1 and regulatory commitment 5644411 is described in Attachment 2.

3.2 Supplemental Risk Information This license amendment request (LAR) is proposed in accordance with the provisions of 10 CFR 50.90 for Technical Specification (TS) 3.8.4 CONDITION B associated with the 2-hour COMPLETION TIME (CT). Although the request is not based on the criteria of Regulatory Guide (RG) 1.17 4, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," (Reference 6.11) and RG 1.177, "An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications," (Reference 6.12) for risk-informed changes, risk information and insights are useful in determining the impact the proposed change may have on plant risk and outlining effective risk management strategies.

3.2.1 Probabilistic Risk Assessment Capability and Insights The baseline Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) contributions from the PRA models are provided in Attachment 9. The total CDF and LERF values are consistent with thresholds referenced in NRC RG 1.17 4, Revision 2 (Reference 6.11) for consideration in review of licensing changes (i.e., CDF less than 1 E-4 per year and LERF less than 1 E-5 per year). The risk impact associated with a one-time extension is provided in Attachment 10 and results are consistent with thresholds referenced in RG 1.177, Revision 1 (Reference 6.12) with effective compensatory measures to reduce the sources of increased risk implemented, but not credited in the quantitative risk evaluation.

CPNPP PRA models do not include quantitative credit for any FLEX or portable equipment.

3.2.2 Avoidance of Risk Significant Plant Configurations CPNPP plant risk associated with the proposed extended 1 E Station Battery COMPLETION TIME is determined from PRA models developed, documented and reviewed with reference to RG 1.200,

Enclosure to TXX-18010 Page 13 of 21

/

Revision 2, Capability Category II standards (Reference 6.14) for internal events, internal flooding, and internal fires with additional risk insights provided from qualitative assessments for seismic events, tornado events, and other external events. Associated actions to avoid or respond to these events through function of the redundant train battery with the Alternate Power Generator (APG) for backup power, protection of the unaffected train of mitigating equipment with associated battery, and protection of offsite power sources, are discussed below.

The dominant risk scenarios associated with unavailability of a 1 E Station Battery include:

Loss of offsite power (i.e., grid, switchyard, or transformer failure)

Fires in the unaffected safety related Switchgear Room, Cable Spreading Room (CSR) and Main

Control Room (MCR) leading to abandonment The dominant risk contributors with a 1 E Station Battery out of service were reviewed to ensure they were minimal and correct as documented in Engineering Evaluation 289A (Reference 6.29). The evaluation includes detailed analysis of the individual top cutsets and significant basic events to identify risk reduction measures.

The dominant impact of all the above scenarios on critical safety functions is the loss of heat removal from the Steam Generators due to failure of all the auxiliary feedwater pumps or loss of power to those pumps. Random or induced loss of coolant accidents do not contribute significantly to the change in risk for the 1 E Station Battery out of service, relative to the overall baseline risk that is reduced due to use of low leakage reactor coolant pump seals at CPNPP.

The PRA analysis assumes that other risk significant plant equipment outage configurations will not occur during the extended COMPLETION TIME period by prohibiting elective maintenance on other PRA risk significant plant equipment (i.e., prohibiting voluntary entry into identified risk management action level configurations) and avoiding other activities that could challenge unit operation or cause fires in risk significant areas as described in the compensatory measures. The use of the average test and maintenance model is considered very conservative based on the controls being taken to eliminate unavailability of equipment for planned maintenance, and the low likelihood of corrective maintenance occurring during the 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months extension period.

The potential for a common cause failure of the remaining available 1 E Station Battery during 18-hour extension period for a degraded 1 E Station Battery is considered minimal based on the cause evaluation.

The failure mechanism is well understood as slow acting. During the proposed COMPLETION TIME, monitoring and prompt corrective actions mitigate conditions such that common cause failure does not contribute to increasing risk.

The PRA analysis identified the following actions to further reduce PRA risk as documented in Engineering Evaluation 289A (Reference 6.29). Included are measures put into place to prevent or reduce the likelihood of the fire scenarios that potentially impact the offsite* power cable or the in-service batteries during the extended CT. These risk reduction measures are being taken during this extended one-time 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT (see Attachment 2 to this enclosure) to address various configuration risks and sensitivity analyses: 1 Posting and control of access to both switchyards and relay houses (in accordance with STA-629

/ Reference 6.15) and suspension of all maintenance for the duration of the CT; implementation of Level 1 controls immediately followed by Level 2 controls within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months The following applies to Unit 1 and Unit 2. Suspension of Maintenance on the Emergency Diesel Generators (EDGs), Alternate Power Generators (APGs), Turbine Driven Auxiliary Feedwater Pumps (TDAFWPs), in-service start-up transformers, Component Cooling Water Pumps (CCWPs) and Station Service Water Pumps (SSWPs) (except for those required to restore equipment from any ongoing maintenance activity). Additionally, during the CT extension, signs will be placed on the doorways to the equipment, or in the case of the in service startup

Enclosure to TXX-18010 Page 14 of 21 transformers, boundary signs, and barrier tape, rope, or chains will be installed around equipment and in-service batteries, inverters, and chargers noting the restriction of testing and maintenance.

Restriction on Transient Combustible Storage - in-service start-up transformers Control and Power Cable Routing, MCR, CSR, unaffected battery room, charger room, and inverter room Suspension of Hot Work Activities - in-service start-up transformers Power and Control Cabling, MCR, CSR, unaffected battery room, charger room, and inverter room.

Roving Hourly Fire Watch - Paths of in-service start-up transformers Power and Control Cabling and in the unaffected battery and inverter/ charger areas I

Due to the limited control afforded from the Remote Shutdown Panel (RSP), focus will be placed on actions to prevent and detect MCR and CSR fires; this will be accomplished by implementing an hourly fire watch for the CSR and conducting a control room briefing to emphasize detection and prevention.

Though not assumed likely based on seasqnal conditions, severe weather during the period of this one-time extended COMPLETION TIME will be monitored as described in Section 3.1.7. These actions mitigate additional plant risk due to events not directly associated with extended 1 E Station Battery unavailability; however, planned risk reduction actions are not credited in the ICCDP and ICLERP values furnished in Attachment 10.

A complete list of inspections, compensatory measures, and conditions are provided in Attachment 1 and regulatory commitment 5644411 is described in Attachment 2.

3.2.3 Risk Informed Configuration Management Risk would also be managed during the extended COMPLETION TIME via the Maintenance Rule 10 CFR 50.65(a)(4) Configuration Risk Management Program (CRMP), which has been reviewed in prior risk-informed Technical Specification change requests (Reference 6.16). The process governing CRMP is described in Engineering Evaluation 289A (Reference 6.29).

Technical Adequacy of the PRA Risk information to supplement the CT extension LAR derives from PRA models and analyses with acceptable quality and level of detail to support use in a risk informed application, but for this application its use will provide risk insights.

The proposed change has been evaluated with a PRA model that documented and reviewed to Capability Category II for all scope and quality requirements of RG 1.200, Revision 2 "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities" (Reference 6.14).

CPNPP employs a multi-faceted approach to establishing and maintaining the technical adequacy and plant fidelity of the PRA models for Comanche Peak. This approach includes both a proceduralized PRA maintenance process and the use of self-assessments, independent reviews and independent peer reviews. Results from peer reviews are documented and addressed; F&O (Facts and Observations) resolutions have been incorporated to establish technical adequacy of the CPNPP PRA model to address the risk impact of the proposed license amendment. No changes to the PRA were required for use in the TS change evaluation. Finding level Facts and Observations (F&Os) not met at Category II have been closed by CPNPP with PRA documents and independent review where applicable. Three Supporting Requirements (SRs) (LE-C11, IFEV-A6 and IFSN-A6) met at Capability Category I had no associated finding level F&O and review determined these did not impact risk results relative to the subject application.

Enclosure to TXX-18010 Page 15 of 21 Internal Events and Internal Flooding Hazards This one-time Technical Specification change evaluation includes results from the CPNPP peer reviewed, plant specific baseline PRA model to quantify Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) due to internal events, including internal flooding, at power. ""J:he CPNPP model maintenance process ensures that the PRA model used in this application reflects the as-built, as-operated plant for each of the two units.

Following a model upgrade and self-assessment, the Comanche Peak PRA was subject to a PWROG full scope peer review in March 2011 in accordance with the 2009 version of the PRA Standard (Reference 6.35). Among the 308 applicable Supporting Requirements (SRs), 94% of SRs met Capability Category II or higher. Finding and Suggestion F&Os, including those associated with Capability Category I or not met SRs, were fully addressed and documented. Subsequent independent reviews confirmed resolutions and closure were adequate with only one suggestion level F&O remaining open. Reference 6.16 presented the safety evaluation for Comanche Peak's TSTF 425 surveillance Frequency Control Program and provided a confirmatory'review of the March 2011 peer review F&O resolutions relative to that application.

No PRA upgrades as defined in the PRA standard have been made to the internal events model since the conduct of the peer review. The.current PRA model, CPNPP MOR 5, has met all Supporting Requirements judged to have significance to this LAR at Capability Category II or better.

The baseline CDF and LERF for the internal events and internal flooding model are provided in of this enclosure.

Fire Hazards This one-time Technical Specification change evaluation includes results from the Revision 1 CPNPP peer reviewed, plant specific PRA model to quantify Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) due to fire hazards, at power. The Fire PRA model is consistent with '

NUREG/CR 6850 (Reference 6.30) methodology with no exceptions. The CPNPP maintenance process ensures the PRA model used in this application reflects the as-built, as-operated plant for each of the two units. The baseline CDF and LERF for the fire model are provided in Attachment 9 of this enclosure. The PWROG peer review was conducted in January 2016. All findings are documented with dispositions demonstrating the model can be used for a quantification of the fire risk metrics and for an identification of significant fire risk contributors and insights. The peer review indicated data, methodologies and fire risk models were appropriate with no unapproved methods (UAMs). Since the peer review, the Comanche Peak fire PRA has been updated to incorporate NUREG-2169 (Reference 6.33), NUREG-2178 (Reference 6.34), and FAQ 14-0009. The NRC has endorsed each of these NUREGs or FAQs as acceptable for use by licensees. The current Comanche Peak Fire PRA model has been developed, documented and reviewed with reference to RG 1.200, Revision 2, Capability Category II standards (Reference 6.14). Peer review and findings dispositions establish technical adequacy of the Fire PRA model to address the risk impact of the proposed license amendment.

The baseline CDF and LERF for the internal fire are provided in Attachment 9 of this enclosure.

Seismic Hazards For seismic events, CPNPP is considered to be in an area of low seismicity. The potential effects from seismic events for the one-time Technical Specification change were considered with reference to the seismic PRA margin analysis was created in support of the Individual Plant Evaluation of External Events (IPEEE). As a reduced scope plant, the IPEEE Seismic analysis used a margin approach that assumed a LOOP and Very Small Break LOCA in a seismic event. Since the class 1 E batteries and their supports are Category I seismic structures, they are assumed to not be damaged (total failure) in the seismic event. The change in risk associated with a battery being OOS for the extended CT is equivalent to the

change in risk seen from the internal events model for random failures. In addition, the frequency of a seismic occurrence over the 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months extended CT is considered small and when considering that a train of safety related equipment would remain available for approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months of the 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT, the overall change in risk due to the extended CT can be considered small. Updated seismic hazard

Enclosure to TXX-18010 Page 16 of 21 3.3

)

information was reviewed in Engineering Evaluation 289A (Reference 6.29) and determined the IPEEE conclusion, that there are no plant-specific vulnerabilities to seismic events at CPNPP, is still appropriate and bounds the expected current day seismic risk impacts for CPNPP.

Other External Hazards A qualitative review was documented in Engineering Evaluation 289A (Reference 6.29) to evaluate other external events for risk impact associated with the requested extension to the battery CT. These assessments considered high winds, external floods, external fire, and other transportation and nearby facility accidents with reference to the analyses done in support of the IPEEE. Scenarios with potential impact from high wind and tornado events were reviewed; results indicate that the bounding case of core damage risk from a tornado strike at CPNPP is quite small. The dominant sequences do not involve tornado-induced failures of plant structures or equipment. This is due to the fact that nearly all risk-significant equipment is well protected within Seismic Category I structures which are designed to withstand tornadoes up to the design basis tornado. Given the relatively low likelihood of a tornado occurring over the time frame of the extended CT and the availability of a train of equipment (including the restrictions identified in Attachment 2 of this submittal), the change in tornado risk as discussed above is considered to be small. Attachment 10 provides the results of the quantitative assessment of the impact of the extended CT due to high winds. The IPEEE concluded that the significant contribution from this hazard was due to the lower range of high wind events. Those event frequencies and IPEEE identified impacts were applied in conjunction with the current internal events model to provide results and insights for this hazard. Individual qualitative assessments from the documented evaluation of other external hazards show changes in risk are small and do not impact the overall conclusions of the quantitative risk assessment for internal events, internal flooding and fire.

PRA Uncertainty Evaluations Three sensitivity studies were conducted to address uncertainty associated with this application. Included were components that become more important under the proposed configuration and their impacts on uncertainty. The assumptions identified as warranting a sensitivity analysis led to evaluation of these potential impacts: (1) increasing important component failure probabilities; (2) no credit for the Alternate Power Generator (APG); and (3) no credit for offsite power recovery for high winds. Parametric uncertainties were examined using standard statistical error propagation techniques and CDF and LERF deviations from the point estimates remained within an acceptance criterion of 10 percent. For uncertainty related to completeness, the proposed changes do not introduce any application-specific sources of uncertainty, and those for the baseline model have been minimized through the use of consensus modeling. The calculations include internal events, internal flood and fire, at power. The proposed configuration is only applicable at-power and other hazard groups (seismic, external events) are unchanged from the Individual Plant Examinations. All of the sensitivity results fell below the reference thresholds in RG 1.174 (Reference 6.11) and RG 1.177 (Reference 6.12) for CDF, ~CDF, ICCDP, LERF,

~LERF, and ICLERP.

Conclusions The results of the deterministic engineering justification described above provides assurance that the systems and equipment required to safely shutdown the plant and mitigate the effects of a design basis accident will remain capable of performing their safety functions.

The calculated risk metric values provided to supplement the deterministic evaluation are all within guidance thresholds and therefore from the risk informed perspective, the proposed change to the CT for one battery inoperable to 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months has a non-risk significant impact on overall plant risk. The qualitative assessments for external events show that the potential for significant change in risk is also small. Given the combination of quantitative and qualitative results, the requested CT extension poses minimal impact to the plant.

Any increases in CDF and LERF are small and consistent-with the NRC Safety Goal Policy Statement and the thresholds referenced in Regulatory Guides 1.17 4 and 1.177.

Enclosure to TXX-18010 Page 17 of 21 Constraints on concurrent maintenance of other equipment while batteries are inoperable are defined to ensure that the risk increase due to the proposed change is small. Based upon these evaluations, including quantitative and qualitative considerations, the risk results and insights support the request to extend the battery CT to 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months .

Risk Reduction measures are provided as commitments in Attachment 2 consistent with the guidance of NUREG-0800 Branch Technical Position 8-8 Recommendations and the supplemental risk information.

A list of inspections, compensatory measures, and conditions are provided in Attachment 1 and regulatory commitment 5644411 is described in Attachment 2.

The proposed TS 3.8.4 REQUIRED ACTION B.2, new NOTE, and COMPLETION TIME are consistent with NRC guidance and meet the following principles:

Meets the current regulations Consistent with defense-in-depth philosophy Maintains sufficient safety margins Even though the affected battery is inoperable due to the disassembly of seismic bracing, it will be available for approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months of the requested 18 hour-COMPLETION TIME. For the planned activity, unavailability is limited to approximately 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and is equivalent to the existing 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months COMPLETION TIME of TS 3.8.4 REQUIRED ACTION 8.1.

In effect, the affected battery is acting as its own temporary supplemental backup power source.

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

4.0 REGULATORY EVALUATION

4.1 Applicable Re 1gulatory Requirements As requited by 10 CFR 50, Appendix A, General Design Criterion (GDC) 17, the Class 1 E DC electrical power system is designed to have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure.

The Class 1 E 125 VDC systems are designed to permit inspection and testing as required by GDC 18.

Periodic testing of Class 1 E batteries is performed on a scheduled basis to demonstrate their operability.

The DC electrical power system conforms to the recommendations of following Regulatory Guides (RGs) and IEEE standards. Compliance with these RGs and IEEE standards is described in Final Safety Analysis Report (FSAR) Section 8.3.2 and Appendix 1A(B) (Reference 6.2);

RG 1.6 dated March 10, 1971, lndepende.nce Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems. (Reference 6.20)

RG 1.32 Rev 2, Criteria For Class 1 E Electric Systems For Nuclear Power Generating Stations.

(Reference 6.21) [IEEE Standard 308-1974 I Reference 6.27]

RG 1.75 Rev 1, Physical Independence of Electrical Systems. (Reference 6.22) [IEEE Standard 384-1974 I Reference 6.28]

RG 1.81 Rev 1, Shared emergency and shutdown electrical systems for multi-unit nuclear power plants, with an exception to Regulatory Position C1, DC systems in multi-unit nuclear power plants should not be shared. (Reference 6.23)

Enclosure to TXX-18010 Page 18 of 21 RG 1.129 Rev 1, Maintenance, Testing, and Replacement of Vented Lead Acid Batteries for Nuclear Power Plants. (Reference 6.24) [IEEE-450-1995 / Reference 6.4]

The proposed change does not affect compliance with these regulations or guidance and will ensure that the lowest functional capabilities or.performance levels of equipment required for safe operation are met.

Section C.6 of Regulatory Guide 1.93, Revision 1, "Availability of Electric Power Sources," (Reference 6.25) states in part, "If the available onsite de power sources are one less than the LCO, power 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 ". The proposed change does deviate from the NRG guidance "should not exceed 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months " on a one-time basis for batteries BT1 ED2 and BT1 ED4 as supported by the Technical Evaluation in Section 3 of this LAR. Additional testing, inspections, and risk reduction measures will be implemented during the extended COMPLETION TIME to minimize the failure of the remaining onsite DC power source of the opposite Train (see Attachments 1 and 2 for additional information).

4.2 Precedent Licensing Actions were reviewed for applicability to LAR 18-001. There were no proposed changes to Technical Specification 3.8.4 CONDITION B identical to those reque~ted by LAR 18-001. However, LAR 18-001 does address specific attributes from one similar NRG approved License Amendment for McGuire in 2014 (Reference 6.13),

4.3 No Significant Hazards Consideration Determination Vistra OpCo has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

1.

Do the proposed changes involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed changes add provisions to increase the COMPLETION TIME (CT) from two hours to eighteen hours, on a one-time basis for Comanche Peak Nuclear Power Plant Class 1 E Batteries BT1 ED2 and BT1 ED4. This one-time increase will only be used once per battery during Unit 1 Cycle 20 (not at the same time). An additional REQUIRED ACTION, new Note, and associated COMPLETION TIME is specified when batteries BT1 ED2 and BT1 ED4, associated with the plant Class 1 E Direct Current (DC) electrical power subsystem, are declared inoperable to replace a jumpered cell. The proposed changes do not physically alter any plant structures, systems, or components, and are not accident initiators: therefore, there is no effect on the probability of accidents previously evaluated. As part of the single failure design feature, loss of any one DC electrical power subsystem does not prevent ttie minimum safety function from being performed. Also, the proposed changes do not affect the type or amounts of radionuclides release following an accident, or affect the initiation and duration of their release. Therefore, the consequences of accidents previously evaluated, which rely on the safety related Class 1 E battery to mitigate, are not significantly increased.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2.

Do the proposed changes create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No

Enclosure to TXX-18010 Page 19 of 21 The proposed.changes do not involve a change in design,,configuration, or method of operation of the plant. The proposed changes will not alter the manner in which equipment is operated, nor will the functional demands on credited equipment be changed. The proposed changes do not impact the interaction of any systems whose failure or malfunction can initiate an accident. There are no identified redundant components affected by these changes and thus there are no new common cause failures or any existing common cause failures that are affected by extending the CT. The proposed changes do not create any new failure modes.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

3.

Do the proposed changes involve a significant reduction in a margin of safety?

Response: No The proposed changes are based upon a deterministic evaluation. This evaluation is supplemented by risk information.

The deterministic evaluation concluded with one inoperable battery associated with the Class 1 E DC electrical power subsystem, the redundant OPERABLE Class 1 E DC electrical power subsystems will be able to perform the safety function as described in the accident analysis.

Supplemental risk information supporting this license amendment request concluded that the additional REQUIRED ACTION, new Note, and associated COMPLETION TIME have a negligible impact on overall plant risk and is consistent with the NRC Safety Goal Policy statement and the thresholds in Regulatory Guide (RG) 1.17 4, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," and RG 1.177, "An Approach for Plant-Specific, Risk-Informed Decisionmaking:

Technical Specifications."

The deterministic evaluation and the supplemental risk information, provide assurance that the plant Class 1 E DC electrical power subsystem will be able to perform its design function with a longer COMPLETION TIME for inoperable batteries BT1 ED2 and BT1 ED4 during Unit 1 Cycle 20, and risk is not significantly impacted by the change. * **

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above evaluations, Vistra OpCo concludes that the propose amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c) and, accordingly, a finding of "no significant hazards consideration" is justified.

4.4 -

Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the

health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be adverse to the common defense and security or to the health and safety of the public.

Enclosure to TXX-18010 Page 20 of 21

5.0 ENVIRONMENTAL CONSIDERATION

S Vistra OpCo has determined that the proposed amendment would change requirements with respect to the installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amount of effluent that may be released offsite, or (iii) a significant increase in the individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), an environmental assessment of the proposed change is not required.

6.0 REFERENCES

6.1 Comanche Peak Unit 1 and Unit 2 Facility Operating Licenses, NPF-87 and NPF-89, (ML053180521 / ML053180525) 6.2 Comanche Peak Units 1 and 2, Transmittal of Electronic Licensing Basis Documents including Certified FSAR Amendment 108, Dated August 1, 2017, (ML17226A097) 6.3 NRC Inspection Report 2013-007, "COMANCHE PEAK NUCLEAR POWER PLANT, UNIT 1 AND UNIT 2, NRC COMPONENT DESIGN BASES INSPECTIQN, NRC INSPECTION REPORT 05000445; 05000446/2013007", dated August 2, 2013 (ML13214A346) 6.4 IEEE-450-1995, "IEEE Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead Acid Batteries for Stationary Applications."

6.5 CPNPP MSE-P1-5003-R1-P3, "Unit 1 Class 1E Station Batteries 18 Month Inspection" 6.6 CPNPP MSE-S0-5000-R7-P1, "CLASS 1 E STATION BATTERIES WEEKLY-MONTHLY-QUARTERL Y SURVEILLANCE TESTS" 6.7 CPNPP OPT-102A-R15-P1 "Operations Shiftly Routine Tests," CPNPP OPT-102A-7-R30-PO, "Local Shiftly Surveillances" 6.8 CPNPP OWl-104-17-R119, "Equipment Log, U1 Turbine" 6.9 CPNPP OPT-215-R15-P3, "Class 1E Electrical Systems Operability," OPT-215-1-R17-P6, "Offsite Transmission Network Operability Data Sheet" 6.10 CPNPP STl-604.05-RO-P2, "On-line Fire Risk Management"

6.11 NRC Regulatory Guide 1.17 4, "An Approach for Using Probabilistic.Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," Revision 3, January 2018.

(ML100910006) 6.12 NRC Regulatory Guide 1.177, '"'An Approach for Plant-Specific, Risk-Informed Decision-making:

Technical Specifications," Revision 1, May 2011. (ML100910008) 6.13 McGuire Nuclear Station received NRC approval on September 10, 2014 (License Amendment 27 4

/ ML14231A634) 6.14 NRC Regulatory Guide 1.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities," Revision 2, March 2009.

(ML090410014) 6.15 CPNPP STA-629-R8-PO, "Switchyard Control and Transmission Grid Interface" 6.16 CPNPP received NRC approval forthe Surveillance Frequency Control Program on June 29, 2012 (ML12067A244) 6.17 NRC NUREG-0800, Standard Review Plan, Section 8.3.2, "DC Power Systems Onsite" Revision 4

- May 2010 (ML100740391) 6.18 NRC NUREG-0800, Branch Technical Position (BTP) 8-8, "Onsite (Emergency Diesel Generators) and Offsite Power Sources Allowed Outage Time Extensions" February 2012 (ML113640138) 6.19 CPNPP ABN-907-R15-P12, "Acts of Nature" 6.20 NRC RG 1.6, "Independence Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems (Safety Guide 6)" 3/10/71 (ML003739924) 6.21 NRC RG 1.32 Revision 2, "Criteria for Safety-Related Electric Power Systems for Nuclear Power Plants" 2/77 (ML003739990) 6.22 NRC RG 1.75 Revision 1, "Physical Independence of Electric Systems," 1/75 (ML13350A340)

\\.

Enclosure to TXX-18010 Page 21 of 21 6.23 NRC RG 1.81 Revision 1, "Shared Emergency and Shutdown Electric Systems for Multi-Unit Nuclear Power Plants," January 1975 (ML003740343) 6.24 NRC RG 1.129 Revision 1, "Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Nuclear Power Plants," February 1978 (ML003740104) 6.25 NRC RG 1.93, Rev 1, "Availability of Electric Power Sources"*

6.26 CPNPP PWTG-R13-P1, "Post Work Test Guide"

s.27

IEEE Standard 308-1974, "Standard Criteria for Class 1 E Power Systems for Nuclear Power Generating Systems" 6.28 IEEE Standard 384-1974, "Trial-Use Standard Criteria for Separation of Class 1 E Equipment and Circuits."

6.29 CPNPP ECE 2.15 Evaluation Log# 289A, CT for TX 3.8.4 Extension LAR Submittal 6.30 NU REG/CR 6850, EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities, dated September 2005 6.31 CPNPP ECA-O.OA-R9-P1, "Loss of All AC Power

6.32 CPNPP ABN-602-R8-P10, "Response to a 6900/480V System Malfunction" 6.33 NUREG 2169, "Nuclear Power Plant Fire Ignition Frequency and Non-Suppression Probability Estimation Using the Updated fire Events Database United States Fire Event Experience Through 2009," January 2015 (ML15016A069) 6.34 NUREG 2178, Refining And Characterizing Heat Release Rates From Electrical Enclosures During Fire (RACHELLE-FIRE) Volume 1: Peak Heat Release Rates and Effect of Obstructed Plume,"

Apri12016(ML16117A300) 6.35, ASME/ANS RA-Sa-2009, "Addenda to ASME/ANS RA-S-2008 Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications," American Society of Mechanical Engir1eers, New York, NY, February 2009 7.0 CHRONOLOGICAL OVERVIEW OF LAR 18~001 Chronological Overview October 1999 - Unit 1 Batteries BT1 ED2 and BT1 ED4 installed November 2017 - Battery BT1 ED4 was declared inoperable in accordance with Technical Specification 3.8.4, CONDITION B, "One or two batteries on one train inoperable" to allow jumpering of ce_ll 41 in battery BT1 ED4. Cell 41 had failed due to a crack in the jar cell with

- electrolyte leal<age on tlieffoor: A ]u-mper was-pTaced across-cell 4 f to re-store battery BT1 Eb4 operability.

April 2018 - Teleconference between NRC and Vistra OpCo to discuss proposed change to TS 3.8.4, "DC Sources - Operating" for Units 1 and 2 to discuss contingent change - only to be used in event battery is inoperable due to cracked cell July 2018 - Battery BT1 ED2 was declared inoperable in accordance with Technical Specification 3.8.4, CONDITION B, "One' or two batter.ies on one train inoperable" to allow jumpering of cell 27 in battery BT1 ED2. Cell 27 was degraded with a crack in the jar cell. A jumper was placed across cell 27 to restore battery BT1 ED2 operability.

September 2018 - LAR 18-001 proposes one-time change to allow replacement of jumpered cells '.

during remainder of Unit 1 Cycle 20 (prior to next Unit 1 refueling outagejn spring of 2019)

October 3, 2018 - requested approval date for LAR 18-001 Prior to Spring 2019 - replace cell 27 in battery BT1 ED2 and cell 41 in battery BT1 ED4 (contingent on NRC approval of LAR 18-001 ). This restores batteries BT1 ED2 and BT1 ED4 to 60 cell configuration in place prior to July 2018 and November 2017 respectively.

Future Activities (not part of LAR 18-001)

Prior to Spring 2019 -Approval of LAR 18-001 and replacement ofcell 27 in BT1 ED2 and cell 41 in BT1 ED4 allows jumpering of additional battery cells if needed due to crack in jar of cell (similar to November 2017 and July 2018)

Spring 2019 - Scheduled replacement of all cells in battery BT1 ED2 and BT1 ED4 to TXX-18010 Page 1 of 2 List of Inspections, Compensatory Measures, and Conditions Summary of Current Routine Inspections (see Section 3.1.4)

Maintenance Surveillances o

Weekly Inspection o

Monthly Inspection o

Quarterly Inspection o

IEEE 450-1995 Quarterly Inspections Operations Surveillance/ Inspections (See Section 3.1.4) o Shiftly Surveillance (area temperature) o Shiftly Tours/ Inspection of batteries Engineering enhanced monitoring / inspections due to cracking (See Section 3.1.4) o Weekly walkdowns of all Class 1 E batteries that have a condition adverse to quality Summary of New Compensatory Measures to be implemented in additidn to the Current Routine Inspections described above Fire Protection Administrative Controls / Protective Measures for the fire areas / fire zones of the affected Unit 1 Train (See Section 3.1.4 and commitment in Attachment 2) o Hourly roving fire watch in the Fire Areas of Concern o

Suspend ongoing "Hot Work" and prohibit start of any new "Hot Work" in the Fire Areas of

~n~rn o

Do not introduce any new transient combustibles, or add to any transient combustibles already authorized in the Fire Areas of ("ncern Grid Stability (see Section 3.1.7 and commitment in Attachment 2) o Prior to entry into TS 3.8.4 REQUIRED ACTION B.2, contact Transmission Grid Controller (TGM) to assure local grid is stable and no anticipated challenges have been identified Prior to entry into proposed TS 3.8.4 REQUIRED ACTION B.2 (see commitment in Attachment 2) o Access to both switchyards and relay houses will be controfled and posted, and all planned maintenance will be suspended for the duration of the CT.

o The following applies to Unit 1 and Unit 2. The EDGs, APDGs, TDAFWPs, inservice startup transformers, CCWPs, and SSWPs will have ALL testing and maintenance activities suspended o

Both Unit 1 and 2 Transient Combustible safe zones identified in the fire assessment, in the unaffected battery/ inverter areas, the Main Control Room (MGR) and the Cable Spread.Room (CSR) and the cable routing paths for the inservice startup transformers will have additional restrictions relating to combustible storage during the extended CT durations.

o All hot work activities along the routing associated with power and control cabling for inservice startup transformers, in the unaffected battery / inverter areas, the MGR and the CSR will be suspended during the CT.

Severe Weather (see Section 3.1.7 and commitment in Attachment 2) o If a Severe Thunderstorm Warning or Tornado Warning is issued per ABN 907 (Reference 6.19) after entry into TS 3.8.4 proposed REQUIRED ACTION 8.2, then exit TS 3.8.4 proposed REQUIRED ACTION B.2 and enter TS 3.8.4 REQUIRED ACTION D.1 (Be in MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months ) and TS 3.8.4 REQUIRED ACTION D.2 (Be in MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months ).

o Once the applicable sev~re weather warning is cancelled and plant system statuses are verified, TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 will be exited and TS 3.8.4 proposed REQUIRED ACTION B.2 will be re-entered and battery cell replacement will continue until completed or 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months from initial entry into TS 3.8.4 proposed REQUIRED ACTION B.2.

o For example:

o TS 3.8.4 proposed REQUIRED ACTION B.2 is entered and battery cell replacement begins.

o One hour after entering TS 3.8.4 proposed REQUIRED ACTION B.2 a Tornado Warning is issued for Somervell County, the county where Comanche Peak is located.

o At that one-hour point TS 3.8.4 proposed REQUIRED ACTION B.2 is exited and TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 are entered.

o One hour after exit from TS 3.8.4 proposed REQUIRED ACTION B.2 and entry into TS 3.8.4 REQUIRED ACTIONs D.1 and D.2, the Tornado Warning for Somervell County is cancelled and forecasts predict no further severe weather.

to TXX-18010 Page 2 of 2 o

TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 are exited and TS 3.8.4 proposed REQUIRED ACTION B.2 is re-entered with 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months remaining to complete battery cell replacement.

List of conditions where CPNPP would not consider using the one-time extended COMPLETION TIME Severe weather is anticipated (see Section 3.1.7 and commitment in Attachment 2)

List of conditions where CPNPP would exit the one-time extended COMPLETION TIME (see section 3.1.7 and commitment in Attachment 2)

Prior to entry into TS 3.8.4 REQUIRED ACTION B.2, CPNPP will verify the following items and every 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months thereafter. If any item is not met, CPNPP will exit TS 3.8.4 REQUIRED ACTION B.2 and enter TS 3.8.4 REQUIRED ACTIONS D.1 and D.2:

a. Both offsite sources available as determined by performance of OPT-215-1, "Offsite Transmission Network Operability Data Sheet"

b. Affected 6.9kV bus steady state frequency is 59.5 - 60.5 Hz (Reference 6.32)

c. The Turbine Driven Auxiliary Feedwater Pump (TDAFW) is OPERABLE per TS 3.7.5, "Auxiliary Feedwater (AFW) System"

d. The plant is not operating under an ACTION statement for an inoperable offsite AC power source or the opposite train Emergency Diesel Generator Similar to the example described in severe weather above, if TS 3.8.4 REQUIRED ACTIONS D.1 and D.2 are entered due to an item (a, b,,c, or d) above not being met and the items are subsequently met, then TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 will be exited and TS 3.8.4 proposed REQUIRED ACTION B.2 will be re-entered and battery cell replacement will continue until completed or 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months from initial entry into TS 3.8.4 proposed REQUIRED ACTION B.2.-

to TXX-18010 Page 1 of 2 Regulatory Commitment (Number 5644411)

(Due DatE:- During the 18 ho_ur COMPLETION TIME)

1. Access to both switchyards and relay houses will be controlled and posted, and all planned maintenance will be suspended for the duration of the CT. This risk reduction measure was selected based on the reliance of offsite power during the CT extension. The measure is selected to deter any potential transmission grid perturbations or trip issues to the 6.9 kV power supplies from either the 345kV or 138kV switchyard. Work in the switchyard is administratively controlled by the Operations Shift Manager (SM) who by plant procedure, STA-629 "Switchyard Control and Transmission Grid Interface," (Reference 6.15) has sole authority to grant access to the

switchyard. By SM authority, any testing or maintenance activities or access to either switchyard

_ will not be permitted, with the exception of normal operator visual inspection rounds.

2.

The following applies to Unit 1 and Unit 2. The EDGs, APDGs, TDAFWPs, inservice startup transformers, CCWPs, and SSWPs will have ALL testing and maintenance activities suspended (except for those required to restore equipment from _any ongoing maintenance activity) for the duration of an extended battery CT. Additionally, during the CT extension, signs will be placed on the doorways to the equipment, or in the case of the inservice startup transformers, boundary signs, and barrier tape, rope, or chains will be installed erected around the equipment and in-service batteries, chargers, and inverters, noting the restriction of testing and maintenance.

These risk reduction measures ensure continued availability of these components for the entire duration of the CT.

3.

For Fire Safety Shutdown Analysis (FSSA) - Fire Areas of Concern vvill have additional r~strictions on combustible storage during the extended CT durations. All "Hot Work" in the Fire Areas of Concern will be suspended. An hourly roving fire watch will be in effect to protect the Fire Areas of Concern. The Fire Areas of Concern are the areas that credit the affected battery for achieving FSSA.

4.

For Risk Mitigation -

a.

Both Unit 1 and 2 Transient Combustible safe zones identified in the fire assessment, in

__ tb_e unaffe_c_ted __ b_atter:y ro_om, charger room, and_inverte[ rooms, the_Main Control.Room __.

(MGR) and the Cable Spread Room (CSR) and the cable routing paths for the inservice startup transformers will have additional restrictions relating to combustible storage

' during the extended CT durations. Implementing this risk reduction measure will reduce the fire risks that were identified for the transient combustible scenarios in the fire analysis.

b.

All hot work activities along the routing associated with power and control cabling for inservice startup transformers, in the unaffected battery room, and charger room, and inverter room, the MCR and the CSR will be suspended during the CT. This is to reduce the risks associated with fires that could damage and thus disable the station transformer cabling.

c.

An hourly roving fire watch will be in effect to protect areas

i.

credited by the' fire assessment, specifically, the unaffected battery room, charger room, and inverter room, the MGR and CSR (to minimize the exposure time for detection and suppr19ssion of potential fires) and ii.

areas containing power and control cabling of the inservice startup transformers (to minimize loss of offsite power).

to TXX-18010 Page 2 of 2

5.

Battery cell replacement will not be scheduled if severe weather conditions are anticipated.

If a Severe Thunderstorm Warning or Tornado Warning is issued per ABN 907 (Reference 6.19) after entry into TS 3.8.4 proposed REQUIRED ACTION B.2, then exit TS 3.8.4 proposed REQUIRED ACTION B.2 and enter TS 3.8.4 REQUIRED ACTION D.1 (Be in MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months ) and TS 3.8.4 REQUIRED ACTION D,2 (Be in MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months ).

Once the applicable severe weather warning is cancelled and plant system statuses are verified, TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 will be exited and TS 3.8.4 proposed REQUIRED ACTION B.2 will be re-entered and battery cell replacement will continue until completed or 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months from initial entry into TS 3.8.4 proposed REQUIRED ACTION B.2.

For example:

o TS 3.8.4' proposed REQUIRED ACTION B.2 is entered and battery cell replacement begins.

o One hour after entering TS 3.8.4 proposed REQUIRED ACTION B.2 a Tornado Warning is issued for Somervell County, the county where Comanche Peak is located.

o At that one-hour point TS 3.8.4 proposed REQUIRED ACTION B.2 is exited and "fsS 3.8.4 REQUIRED ACTIONs D.1 and D.2 are entered.

o One hour after exit from TS 3.8.4 proposed REQUIRED ACTION B.2 and entry into TS 3.8.4 REQUIRED ACTIONs D.1 and D.2, the Tornado Warning for Somervell County is cancelled and forecasts predict no further severe weather.

o TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 are exited and TS 3.8.4 proposed REQUIRED ACTION B.2 is re-entered with 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months remaining to complete battery cell replacement.

6.

Prior to entry into TS 3.8.4 REQUIRED ACTION 8.2, CPNPP will contact the Transmission Grid Controller (TGM) to ensure:

the local grid is stable and no anticipated challenges have been identified Prior to entry into TS 3.8.4 REQUIRED ACTION B.2, CPNPP will verify the following items and every 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months thereafter. If any item is not met, CPNPP will exit TS 3.8.4 REQUIRED ACTIONS B.2 and enter TS 3.8.4 REQUIRED ACTIONS D.1 and D.2:

a.

Both offsite sources available as determined by performance of OPT-215-1, "Offsite Transmission Network Operability Data Sheet"

b.

Affected 6.9kV bus steady state frequency is 59.5 - 60.5 Hz (ABN-602)

c.

The Turbine Driven Auxiliary Feedwater Pump (TDAFW) is OPERABLE per TS 3.7.5, "Auxiliary Feedwater (AFW) System"

d.

The plant is not operating under an ACTION statement for an inoperable offsite AC power source or the opposite train Emergency Diesel Generator Similar to the example described in severe weather above, if TS 3.8.4 REQUIRED ACTIONS D.1 and D.2 are entered due to an item (6.a, b, c, or d) above not being met and the items are subsequently met, then TS 3.8.4 REQUIRED ACTIONs D.1 and D.2 will be exited and TS 3.8.4 proposed REQUIRED ACTION B.2 will b~ re-entered and battery cell replacement will continue until completed or 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months from initial entry into TS 3.8.4 prop~sed REQUIRED ACTION B.2.

to TXX-18010 Page 1 of 2 3.8 ELECTRICAL POWER SYSTEMS 3.8.4 DC Sources -- Operating DC Sources -- Operating 3.8.4 LCO 3.8.4 The Train A and Train B DC electrical power subsystems shall be OPERABLE.

APPLICABILITY:

MODES 1, 2, 3, and 4 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or two required battery A.1 Restore affected battery(ies) terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months chargers on one train voltage to greater than or equal to the inoperable.

minimum established float voltage.

AND A.2 Verify affected battery(ies) float Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months current ::; 2 amps.

AND Insert A Restore required battery charger(s) 7 days OPERABLE status.

B. One or two batteries on one 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months train inoperable.

C. One DC electrical power C.1 Restore DC electrical power 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months subsystem inoperable for subsystem to OPERABLE status.

reasons other than Condition A or B.

COMANCHE PEAK - UNITS 1 AND 2 3.8-23 Amendment No. 150 to TXX-18010 Page 2 of 2 Insert A (Note: Proposed changes are cloudedi ACTIONS CONDITION B.

One or two batteries on one B.l tra in inoperable.

REQUIRED ACTION Restore affected battery(ies) to OPERABLE status.

B. 2

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

Req u ired Action B.2 is applicable for a one-time basis to replace cell 27 in battery BT1ED2 and cell 41 in battery BT1ED4 during Unit 1 Cycle 20 (not at the same time). If the second battery on the same train becomes inoperable, immediately initiate Required Actions D.l and D.2.

Restore affected battery to OPERABLE status.

COMPLETEION TIME 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 18 hours to TXX-18010 Page 1 of 2 BASES ACTIONS (continued) pnsert B

)

8.1 DC Sources - Operating B 3.8.4 Condition B represents one train with one or two batteries inoperable. With one or two batteries inoperable, the affected DC bus(es) are being supplied by their associated OPERABLE battery charger(s). Any event that results in a loss of the AC bus supporting the battery charger(s) will also result in loss of or degraded DC to that train. Recovery of the AC bus, especially if it is due to a loss of offsite power, will be hampered by the fact that many of the components necessary for the recovery (e.g., diesel generator control and field flash, AC load shed and diesel generator output circuit breakers, etc.)

likely rely upon DC power being supplied from the batteries. In addition, the energization transients of any DC loads that are beyond the capability of the associated battery charger(s) and normally require the assistance of the batteries will not be able to be brought online. The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months limit allows sufficient time to effect restoration of an inoperable battery given that the majority of the conditions that lead to battery inoperability (e.g., loss of battery charger, battery cell voltage less than 2.07 V, etc.) are identified in Specifications 3.8.4, 3.8.5, and 3.8.6 together with additional specific completion times.

C.1 Condition C represents one train with a loss of ability to respond to an event, and a loss of ability to remain energized during normal operation. It is, therefore, imperative that the operator's attention focus on stabilizing the unit, minimizing the potential for complete loss of DC power to the affected train. The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months limit is consistent with the allowed time for an inoperable DC distribution system train.

If one of the required DC electrical power subsystems is inoperable, the other DC electrical power subsystem has the capacity to support a safe shutdown and to mitigate an accident condition. Since a subsequent worst case single failure could, however, result in the loss of the minimum necessary DC electrical subsystems to mitigate a worst case accident, continued power operation should not exceed 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months Completion Time is based on Regulatory Guide 1.93 (Ref. 7) and reflects a reasonable time to assess unit status as a function of the inoperable DC electrical power subsystem and, if the DC electrical power subsystem is not restored to OPERABLE status, to prepare to effect an orderly and safe unit shutdown.

( continued)

COMANCHE PEAK - UNITS 1 AND 2 B 3.8-50 Revision 72 to TXX-18010 Page 2 of2 Insert B The completion time for restoring the inoperable battery to OPERABLE status can be extended to 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months , on a one-time basis for batteries BT1ED2 and BT1ED4 during Unit 1 Cycle 20. This one-time change regains margin by allowing replacement of cell number 27 in battery BT1ED2 and cell 41 in battery BT1ED4 (not at the same time). The 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months completion time for action B.2 is based on a deterministic evaluation supplemented by risk insights.

to TXX-18010 Revised (Clean) TS Pages (4 total pages) List of Pages TS Page 3.8-23 TS Page 3.8-24 TS Page 3.8-2?

\\

3.8 ELECTRICAL POWER SYSTEMS 3.8.4 DC Sources -- Operating DC Sources -- Operating 3.8.4 LCO 3.8.4 The Train A and Train B DC electrical power subsystems shall be

APPLICABILITY:

ACTIONS CONDITION OPERABLE.

MODES 1, 2, 3, and 4 REQUIRED ACTION

\\

COMPLETION TIME*

A. One or two required battery' /l..1. Restore affected battery(ies) terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months chargers on one train.

voltage to greater than or equal to the inoperable.

minimum established float voltage.

AND A.2 Verify affected battery(ies) float current :s; 2 amps.

AND Once per 12.hours A.3 Restore required battery charger(s) 7 days to OPERABLE status.

COMANCHE PEAK - UNITS 1 AND 2

. 3.8-23 Amendment No. 4W, I

(

ACTIONS (continued)

B. One or two batteries on-one B.1 train inoperable.

OR B.2 C. One DC electrical power C.1 subsystem inoperable for reasons other than Condition A or B.

D. Required Action and D.1 Associated Completion Time not met.

AND D.2 Restore affected battery(ies) to OPERABLE status.

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

Required\\Action B.2 is applicable for a one-time basis to replace cell 27 in battery BT1 ED2 and cell 41 in battery BT1 ED4 during Unit 1 Cycle 20 (not at the same time). If the second battery on the same train becomes inoperable, immediately initiate Required Actions D.1 and D.2.

Restore affected battery to OPERABLE status.

Restore DC electrical power subsystem to OPERABLE status.

\\

Be in MODE 3.

Be in MODE 5.

DC Sources -- Operating*

3.8.4 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 18 hours 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 6 hours 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months COMANCHE PEAK - UNITS 1 AND 2 3.8-24 Amendment No. 150, 156,

DC Sources -- Operating 3.8.4 SURVEILLANCE REQUIREMENTS

-SR 3.8.4.1 SR 3.8.4.2 SR 3.8.4.3 SURVEIL,LANCE

\\1erify battery terminal voltage is greater than or equal to the minimum established float Voltage.

Verify each battery charger supplies ~ 300 amps at greater than or equal to the minimum established charger test voltage for~ 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

OR Verify each battery charger can recharge the battery to the

- fully charged state within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months while supplying the largest combined demands of the various continuous steady state loads, after a battery discharge to the bounding design basis event discharge state.

NOTES----------------------------------

1. The modified performance discharge test in SR 3.8.6.6 may be performed in lieu of SR 3.8.4.3.

2. Verify requirement during MODES 3, 4, 5, 6 or with core off-loaded.

FREQUENCY In accordance with the Surveillance' Frequency Control Program.

In accordance with the Surveillance Frequency Control Program.

Verify battery capacity is adequate to supply, and maintain In accordance with in OPERABLE status, the required emergency loads for the the Surveillance design duty cycle when subjected to a battery service test. Frequency Control

, Program.

COMANCHE PEAK - UNITS 1 AND 2 3.8-25 Amendment No. 150, 156,

Attachment.6 to TXX-18010 Page 1 of 3 CPNPP Response to NRC Summary of April 10, 2018, Public Teleconference On April 10, 2018, a teleconference was held between the U.S. Nuclear Regulatory Commission (NRG) and representatives of Vistra Operations Company, LLC (Vistra OpCo, the licensee). The purpose of the meeting was to discuss Vistra OpCo's proposed change to Technical Specification (TS) 3.8.4, "DC [Direct Current] Sources -- Operating," for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2 (CPNPP). In advance of the meeting, the Vistra OpCo provided presentation slides (ADAMS Accession No. ML18095A171 ). On April 6, 2018, prior to the meeting, the NRG transmitted topics of discussion (ADAMS Accession No. ML180968451) to Vistra OpCo generated from the presentation slides. On April 18, 2018, the NRG transmitted a summary of the April 10, 2018, meeting to Vistra OpCo (ADAMS Accession No. ML18106A009).

The proposed changes to TS 3.8.4 discussed on April 10, 2018, were one-time actions in the event a cracked battery cell resulted in an inoperable battery.

Key differences between the changes as discussed on April 10, 2018, and as proposed in the Enclosure to TXX-18010:

As discussed on April 10, 2018 Changes as proposed in Enclosure to TXX-18010 Affected Equipment:

Affected Equipment:

Unit 1 batteries BT1 ED1, BT1 ED2, Unit 1 batteries BT1 ED2, BT1 ED4 BT1ED3,BT1ED4 Unit 2 batteries BT2ED1, BT2ED2, BT2ED3, BT2ED4 One-time contingent change - only to be used in One-time planned change to replace currently event battery is inoperable due to cracked cell jumpered cell 27 in battery BT1 ED2 and cell 41 in battery BT1 ED4 (due to crack in cell jar)

Reactive, potential to be implemented during off Planned work activities, minimizes risk significant normal hours configurations/ conditions (e.g., severe weather)

Requested as a "normal" license amendment Requested as an "exigent" license amendment request with a quick turnaround review.

per 10 CFR 50.91 (a)(6) to TXX-18010 Page 2 of 3 The NRC Meeting Summary dated April 18, 2018, identified information which would need to be addressed in a proposed license amendment in order for the NRC to consider reviewing a proposed amendment. Below is the information identified by the NRC and CPNPP's response.

NRC Item 1 The operating and maintenance history of the batteries, including the current condition of the batteries.

CPNPP Response to Item 1 See Section 3.1.6 of Enclosure to TXX-18010.

NRC Item 2 The proposed battery replacement schedule and the basis for the schedule.

CPNPP Response to Item 2 See Section 3.1.6 of the Enclosure to TXX-18010.

NRC Item 3 A list of conditions where the licensee would not consider using the extended completion time, if approved by the NRG staff.

CPNPP Response to Item 3 See Section 3.3 of the Enclosure to TXX-18010.

NRC Item 4 A list of compensatory measures to maintain defense-in-depth during the extended completion time, including a differentiation between what compensatory measures they are doing currently (routine) and what compensatory measures will be implemented as a result of the extended completion time (new/additional).

CPNPP Response to Item 4 Compensatory measures to maintain defense-in-depth are discussed in several sections of the Enclosure to TXX-18010 and summarized in Section 3.3.

to TXX-18010 Page 3 of 3 NRC Item 5 Most importantly, a description of the supplemental power source that is available as a backup to the inoperable battery during the extended completion time.

CPNPP Response to Item 5 The new proposed REQUIRED ACTION B.2 for TS 3.8.4 includes an 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months COMPLETION TIME to restore the affected battery to OPERABLE status. The 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months time is based on the replacement activities discussed in Section 2.4 of the Enclosure to TXX-18010 (with some margin).

Even though the affected battery is inoperable due to the disassembly of seismic bracing, it will be available for approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months of the requested 18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months COMPLETION TIME. In effect, the affected battery is acting as its own temporary supplemental backup power source.

This is similar to the supplemental backup power source utilized by McGuire in 2014 (Reference ML14231A634).

Other options were considered such as location of a full size temporary battery located nearby in a seismic, category 1 structure, non-seismic category 1 structure, or use of flex equipment.

However, these options introduced other complications such as train related cable separation challenges, cable length challenges, ventilation availability, security interface, and fire protection challenges, i.e., potential impact on other protected safety related SSCs due to a lack of fire barriers.

For seismic events, CPNPP is considered to be in an area of low seismicity. The overall likelihood of a seismic event occurring during the extended CT can be considered small.

to TXX-18010 Page 1 of 4 Supporting Figures for License Amendment Request 18-001 Figure 1-Safety Related DC Sources Train A and B Figure 2 - Battery Room Arrangement Figure 3 - Train A Battery Room to TXX-1801 O Page 2 of 4 MCC uEB3-1 MCC uEB1-1 I BC+-2 II BC+-1 I

,}-------,J I

I I)

( ( ( IV,PC1 10 KVA DIST DIST DIST,__ _

PNL PNL PNL uED1-1 XED1-2 uED1 -2 I

uPC1 MCCuEB~1 MCCuEB~1 I BC+-1 II BC+-2 i

,}-------,J DIST DIST DIST PNL PNL PNL ~~~

uED2-1 XED2-1 uED2-2 I

uPC2 BTuED1 T

uED1

(

I uEC1 BTuED2 T

uED2

(

IV uEC2 10 KVA I

uEC2 TRAINA SAFEGUARDS 125V D.C.

IV uEC1/3 10 KVA Ci MCC uEB1-1 MCC uEB3-1 I BC,~03-1 11 BC +-2 I

}-------J I

I Ci IV uEC3 10 KVA I

uEC5 MCC uEB2-1 MCC uEB4-1 TRAIN B SAFEGUARDS 125V D.C.

i BC,~04-1 ii BC +-2 i

}-------J IV uEC2/4 10 KVA I

I Ci IV uEC4 10 KVA I

uEC6 Figure 1 - Safety Related DC Sources / Train A and B BTuED3 T

uED3 I

uPC3 uED4 c'

IV uPC4 10 KVA I

uPC4

(

I

(

DIST PNL uED3-1 BTuED4 T

( I

(

DIST PNL uED4-1 to TXX-18010 Page 3 of 4 r---------------------------------,

BT1ED2 Train B Train A I

BT1 ED4 1-------------1 BT1ED4 I

1 BT1ED2 1

L---------------------------------1 Dist. Panel 1 ED2 I I Dist. Panel 1 ED4 IV1 PC4 IV1 EC4 DDDDD IV1 PC2 IV1 EC2 IV1 EC2/4 BC1 ED2-2 BC1 ED2-1 BC1 ED4-1 BC1 ED4-2 II 11 11 I

U1 TRN 8 UPS RM Fan Coil U1 TRNA UPS RM Fan Coil

_.I._I __ __.I._I __ __.I I~--~*

BC1ED1-2 BC1ED1-1 BC1ED3-1 BC1ED3-2

~-~

IV1PC1 IV1EC1 IV1EC1/3 DDDDD IV1PC3 IV1EC3 Dist. Panel 1 ED1 I I Dist. Panel 1 ED3 BT1ED1 1

BT1ED3 1-------------1 BT1ED3 24/48 VDC BT1D3 BT1D1

[I] [D I

II II I

BC1D3 BC1013 BC101 B

B 0BC1D4 T 125/250 T

Dist. D 1

1 D Dist.

Panel D

VDC D

Panel 1 D1 2

4 1D2 DBC102 BC1024 D D

IV1C2 BYP SW Figure 2 - Battery Room Arrangement (Typical)

IV1C2 D

D IV1C3 BYP SW

!BT1ED2 !

!BT1 ED1 !

to TXX-18010 Page 4 of 4 (4 rows with 15 cells on each row)

Figure 3 - Train A Battery Room (Typical)

BTuED1/2 (4 rows with 15 cells on each row) to TXX-18010 Page 1 of 4 Supporting Tables for License Amendment Request 18-001 Table 1-Estimated Time to Replace Jumpered Cell Table 2 - Voltage Margin - Class lE Batteries Table 3.,__ Currently Installed Safety Related Batteries Operational and Maintenance History to TXX-18010 Page 2 of 4 Table 1 Estimated Time to Replace Jumpered Battery Cell

. \\

Activity Description Hours Activity Elapsed Declare battery inoperable 0

0 Dis-assembly of seismic bracing of battery rack 5

5 Open battery dis-connect 0

5 Remove/ Replace jumpered battery cell 2

7 Close battery dis-connect 0

7 Initiate battery float charge 1

15(a)

Re-assembly of seismic bracing of battery rack 8

15(a)

Post work testing(b) 1 15(a)

Margin 3

18 Declare battery OPERABLE 0

18 Notes:

Available Yes Yes No No Yes*

Yes Yes Yes Yes Yes (a) Activities "Initiate battery float charge", "Re-assembly of seismic bracing of battery rack",

and "Post work testing" occur in parallel.

(b) Post work testing includes (CPNPP PWTG-R13-P1) (Reference 6.26)-

Inspection check of:

1) electrolyte level/temperature/specific gravity I

2) battery intercell connector torque Operational check:

3) terminal voltage (TS SR 3.8.4.1)

4) capacity test

5) discharge test

6) connector resistance

7) thermoscan

8) float current (TS SR 3.8.6.1)

(CPNPP MSE-P1-5003-R1-P3) -

DLRO Inspection to TXX-.18010 Page 3 of 4 BATTERY BT1ED1 BT1ED2<cl BT1ED3 BT1ED4<cl BT2ED1 BT2ED2 BT2ED3 BT2ED4 Notes:

Table 2

,Voltage Margin<a> - Class 1 E Batteries Battery Duty Cycle Calculated Load Step Voltage 0 -1 Minute 113.82 1 - 239 Minutes 114.60 239 - 240 Minute 112.50 0 -1 Minute 114.30 1 - 239 Minutes 114.60 239 - 240 Minute 112.38 0 - 240 Minutes 113.28 0 - 240 Minutes 111.90 0 -1 Minute 113.82 1 - 239 Minutes 114.00 239 - 240 Minute.

111.72 0 -1 Minute 114.18 1 - 239 Minutes 113.88 239 - 240 Minute 111.60 0 - 240 Minutes 113.28 0 - 240 Minutes 111.90 Required Voltage Voltage Margin

112.18 1.642(b) 103.95 10.65 108.70 3.80 111.30 3.00 103.69 10.91 107.11 5.27 102.08 11.20 101.23 10.67 113.29 0.53(b) 103.54 10.46 107.41 4.31 114.06 o.12<b) 102.72 11.16 108.62 2.98 102.31 10.97 101.31 10.59 (a) Each battery's cell voltage is approximately 1.9 voe. A battery voltage margin of equal to or greater than 1.9 voe will allow jumping of a cell.

(b) The battery voltage margin for BT1 ED1, BT2ED1, and BT2ED2 during first minute of the battery I

duty cycle is not sufficient hallow a cell to be jumpered. Voltage margin for batteries BT1 ED1 and BT2ED1, and BT2ED2 is re-assessed considering battery connected load diversity/demand factor of 80% and momentary load diversity/demand factor of 95% and BT2ED2 room temperature of>

770 F. With potential jumping of a cell the voltage margin of for batteries BT1 ED1, BT2ED1, and BT2ED2 will be 1.24 V, 0.25 V, and 0.04 V respectively.

(c) Included in one-time license amendment request to allow replacement of currently jumpered cell.

' to TXX-18010 Page 4 of 4 Battery MPT(aJ Date 04/13/2001 BT1ED1<bl 10/16/2005 04/11/2010 10/06/2014 10/18/1999 04/12/2004 BT1ED2M 10/07/2008 04/02/2013 10/24/2017 04/10/2001 BT1ED3 10/19/2005 04/12/2010 10/06/2014 10/18/1999 04/12/2004 BT1ED4 10/07/2008 04/01/2013 10/22/2017 10/04/2000 04/18/2002 BT2ED1<bl 10/09/2006 04/13/2011 10/10/2012 04/16/2017 BT2ED2Cbl 10/17/2009 04/01/2014 04/18/2002 BT2ED3 10/09/2006 04/13/2011 04/17/2017 04/13/2005 BT2ED4 10/17/2009 03/31/2014 Notes:

Table 3 Currently Installed Safety Related Batteries Operational and Maintenance History Capacity Work Installed

(%)

Order Date 97.8 259090 104.3 287972 04/08/2001 104,3 3888979 103 4693118 102 256581 101.4 259091 104.6 3611790 10/17/1999 106.6 4430129 105.6 5364098

./

101.33 259092 104 287789 04/05/2001 104.6 3888968 102.6 4693125 101 256583 101.66 259093 102.3 3611795 10/14/1999 105.6 4430134 97.6 5364093 98.3 256774 103.66 277841

~03.5 382465 10/16/2000 96.34 408780 99.3 4320250 103.6 4491553 102 3677467 10/16/2006 101.33 4656719 104.7 277843 105 382466 04/15/2002 103.3 408781 98 4884159 102 364275 105 3677472 03/31/2005 104 4656739 (a) Modified Performance Test (MPT)

Scheduled Replacement (all 60 cells) 1RF21, Fall 2020 1 RF20, Spring 2019 (LAR 18-001 to request replacement of cell 27 in Unit 1 cycle 20) 1 RF21, Fall 2020 1 RF20, Spring 2019 (LAR 18-001 to request replacement of cell 41 in Unit 1 cycle 20) 2RF19, Fall 2021 2RF22, Spring 2026 2RF19, Fall 2021 2RF21, Fall 2024 (b) These batteries will be modified (addition of one battery cell) in 2RF17 (Fall 2018) and 1 RF20 (Spring 2019). This modification will be evaluated under 10 CFR 50.59 and is NOT part of this LAR.

tq TXX-18010 Page 1 of 1 Baseline Average Annual CDF/LERF

\\

Hazards Unit 1 CDF (per.

Unit 1 LERF (per reactor year) reactor year)

Internal Events and 1.41E-06 1.'18E-07 Internal Flooding Internal Fire 4.27E-05 3.53E-06 High Winds1 2.22E-08 1.41E-09 Total 4.41E-052 3.65E-063 Notes:

1.

Updated baseline CDF / LERF values from IPEEE high wind analysis for Fl and F2 tornados

2.

Total CDF is below the RG 1.174 referenced threshold of< lE-4 per year

3.

Total LERF is below the RG 1.174 referenced threshold of <.lE-5 per year

References:

1.

NRC Regulatory Guide 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to.the Licensing Basis," Revision 3, January 2018

2.

R&R-PN-022, Level 1 Internal Events Quantification, Revision 5

3.

R&R-PN-035, Level 2 Internal Events Quantification, Revision 5

4.

R&R-PN-021, Internal Flood Analysis, Revision 4B

5.

CN-RAM-038, Fire PRA Quantification, Revision 1

6.

Engineering Evaluation 289A, "CT for TS 3.8.4 Extension LAR Submittal -Supplemental"

7.

ER-EA-008, "IPEEE for Severe Accident Vulnerabilities," June 1995 0 to TXX-18010 Page 1 of 1 0 ICCDP and ICLERP for One-Time Technical Specification Change Notes:

Hazards Internal Events Internal Fire High Winds2

'1\\ital Delta CDF (per reactor year) 2.73E-08 3.09E-08 8.82E-10 s*.91E-08 lEDl Results1 ICCDP (18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT) 2.73E-08 3.09E-08 8.82E-10 5.91E-6M Delta LERF (per ICLERP

,,-reactor year)

(18 hour2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months CT) l.90E-09 l.90E-09 6.SlE-10 6.SlE-10 5.97E-11 5.97E-11 2:61E009 2.61E-094

1.

The lEDl case is presented here as it was determined to be bounding for Unit 1 station battery cases. Additionally, asymmetric results were noted for UED3 and UED4 and determined to correspond to limited PRA modeled loads (DC distribution panels)

\\

2.

Bounding value with battery out of service from IPEEE high wind analysis for Fl and F2 tornados

3.

Total JCCDP is below the RG 1.177 referenced threshold of< lE-5 per year with effective compe~satory measures not credited in the quantitative risk evaluation

4.

Total ICLERP is below the RG 1.177 referenced threshold of< lE-6 per year with effective compensatory measures not credited in the quantitative risk evaluation Refe~ences:

1.

Regulatory Guide 1.177, An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications, Revision 1, dated May 2011

2.

Engineering Evaluation 289A, "CT for TS 3.8.4 Extension LAR Submittal"

v t e Letter Sequence Request
EPID:L-2018-LLA-0238, TSTF-425 (Approved, Closed)
Initiation Request Acceptance... Supplement Administration Questions 14 September 2018 Answers 20 September 2018 Results Approval, Approval, Approval Other: ML18254A013, ML18254A016, ML18276A026, ML18276A029
MONTHYEAR2018-09-12 [Table View]

CP-201800112, Submittal of Exigent License Amendment Request (LAR) 18-001, Revision to Technical Specification 3.8.4, DC Sources - Operating, Condition B

Text

SUBJECT:

Dear Sir or Mc;1dam:

SUMMARY

3.0 TECHNICAL EVALUATION

4.0 REGULATORY EVALUATION

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

SUMMARY

3.0 TECHNICAL EVALUATION

4.0 REGULATORY EVALUATION

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

References:

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CP-201800112, Submittal of Exigent License Amendment Request (LAR) 18-001, Revision to Technical Specification 3.8.4, DC Sources - Operating, Condition B

Text

SUBJECT:

Dear Sir or Mc;1dam:

SUMMARY

3.0 TECHNICAL EVALUATION

4.0 REGULATORY EVALUATION

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

SUMMARY

3.0 TECHNICAL EVALUATION

4.0 REGULATORY EVALUATION

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

References:

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