CP-202000575, (CPNPP) - Exigent License Amendment Request (LAR) 20-007 Revision to Technical Specification (TS) 3.7.8, Station Service Water System and TS 3.8.1, AC Sources - Operating

(CPNPP) - Exigent License Amendment Request (LAR)20-007 Revision to Technical Specification (TS) 3.7.8, Station Service Water System and TS 3.8.1, AC Sources - Operating

ML20324A627
Person / Time
Site:	Comanche Peak
Issue date:	11/19/2020
From:	Thomas McCool Luminant, Vistra Operations Company
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-202000575, TXX-20086
Download: ML20324A627 (73)

Text

m Luminant CP-202000575 TXX-20086 November 19, 2020 U. S. Nuclear Regulatory Commission A TIN: Document Control Desk Washington, DC 20555-0001 Thomas P. McCool Site Vice President

Subject:

Comanche Peak Nuclear Power Plant (CPNPP)

Docket Nos. 50-445 and 50-446 Exigent License Amendment Request (LAR)20-007 Comanche Peak Nuclear Power Plant (Vistra Operations Company LLC)

P.O. Box 1002 6322 North FM 56 Glen Rose, TX 76043 T 254.897.6042 Ref 10 CFR 50.90 10 CFR 50.91(b)(l)

Revision to Technical Specification (TS) 3.7.8, "Station Service Water System" And TS 3.8.1, "AC Sources - Operating"

Dear Sir or Madam:

Pursuant to 10 CFR 50.90 and 10 CFR 50.91, Vistra Operations Company LLC (Vistra OpCo) hereby requests an exigent amendment to the Comanche Peak Nuclear Power Plant (CPNPP) Unit 1 and Unit 2 Technical Specifications. The one-time exigent license amendment is required due to the degrading performance of CPNPP Unit 2 Station Service Water System Pump 2-02 (Train B).

The proposed change will revise Technical Specification 3.7.8, "Station Service Water System," and 3.8.1, "AC Sources - Operating." The proposed change will implement a one-time change to TS 3.7.8, CONDITION Band TS 3.8.l CONDITION B. This change is necessary to permit a net increase in plant safety and reliability without inducing transient risk. Restoring a more stable and reliable SSW Pump on Unit 2, Train Bis in the public interest, as an unnecessary plant shutdown could be caused by failure of the SSW Pump 2-02. The loss of a CPNPP unit electrical output would challenge the Electric Reliability Council of Texas (ER COT) grid if it occurs during high grid demand.

The Enclosure provides a description and assessment of the proposed changes. Attachment 1 lists the Regulatory Commitments that will be in place during implementation of the proposed one-time TS change. Attachment 2 provides an excerpt from the CPNPP Post Work Test Guide to illustrate the testing required following SSW Pump 2-02 replacement. Attachment 3 provides a markup of the current TS pages and the retyped TS pages. Attachment 3 also provides" for information only" a markup of the current TS Bases and the retyped TS Bases pages. Attachment 4 provides supporting tables and figures for this license amendment request. Attachment 5 provides the "Baseline Average Annual CDF / LERF" data used to provide risk insights for this license amendment request. Attachment 6 provides the "ICCDP and ICLERP for one-time Technical Specification Change" data used to provide risk insights for this license amendment request.

Vistra OpCo has determined that the proposed change does not involve a significant hazards consideration pursuant to 10 CFR 50.92(c), and there are no significant enviromnental impacts associated with the change. The CPNPP Station Operations Review Committee (SORC) has reviewed

TXX-20086 Page 2 of 2 the proposed license amendment. In accordance with 10 CFR 50.91(b)(l), a copy of the proposed license amendment is being forwarded to the State of Texas.

NRC staff review and approval of the proposed license amendment is requested by February 12, 2021, in order to implement the change so the maintenance may begin February22 2021. Once approved, the amendment shall be implemented prior to work starting and no more than 60 days after approval.

This letter contains a commitment regarding CPNPP Units 1and2 as described in Attachment 2.

Should you have any questions, please contact Carl Corbin at (254) 897-0121 or carl.corbin@luminant.com.

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

Executed on November 19, 2020.

Sincerely, Thomas P. McCool

Enclosure:

Exigent License Amendment Request (LAR)20-007 Revision to Technical Specification (TS) 3.7.8, "Station Service Water System" Attachments: 1.

Regulatory Commitment No. 5966825 c (email) -

2.

CPNPP Post-Work Test Guide Excerpt-Pumps

3.

Technical Specification pages (Markup and Retype) and Technical Specification Bases pages (For Information Only-Markup and Retype)

4.

Supporting Tables and Figures for LAR 20-007

5.

Baseline Average Annual CDF /LERF

6.

ICCDP and ICLERP for one-time Technical Specification Change Scott Morris, Region IV [Scott.Morris@nrc.gov]

Dennis Galvin, NRR [Dennis.Galvin@nrc.gov]

John Ellegood, Senior Resident Inspector, CPNPP Uohn.Ellegood@nrc.gov]

Neil Day, Resident Inspector, CPNPP [Neil.Day@nrc.gov]

Mr. Robert Free [robert.free@dshs.state.tx.us]

Environmental Monitoring & Emergency Response Manager Texas Department of State Health Services Mail Code 1986 P.O. Box 149347 Austin, TX 78714-9347

Enclosure to TXX-20086 Page 1 of 37 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

2. 1 System Design and Operation 2.2 Current Technical Specification Requirements 2.3 Reason for Proposed Change 2.4 Description of Proposed Change

3.0 TECHNICAL EVALUATION

3.1 Deterministic Evaluation 3.2 Safety Systems Affected by the Proposed Change 3.3 Additional Considerations for Safe Shutdown 3.4 Supplemental Risk Information 3.5 Assumptions, Inspections, and Regulatory Commitment 3.6 Evaluations of Safety Margins

3. 7 Conclusions

4.0 REGULATORY EVALUATION

4. 1 Applicable Regulatory Requirements I Guidance 4.2 Precedent 4.3 No Significant Hazards Consideration Determination 4.4 Conclusions

5.0 ENVIRONMENTAL CONSIDERATION

S

6.0 REFERENCES

ATTACHMENTS

1.

Regulatory Commitments Number 5966825 - During Unit 2 Station Service Water System extended COMPLETION TIME

2.

CPNPP Post-Work Test Guide excerpt for unit Service Water Pump testing following replacement

3.

Technical Specification pages (Markup and Retype) and Technical Specification Bases ages (For Information Only - Markup and Retype)

4.

Supporting Tables and Figures for LAR 20-007 [For Information Only]

5.

Baseline Average Annual CDF/LERF

6.

PRA Analysis for one-time Technical Specification Change

Enclosure to TXX-20086 Page 2 of 37 1.0

SUMMARY

DESCRIPTION Proposed Exigent License Amendment Request (LAR)20-007 is to revise Technical Specifications (TS) 3.7.8, "Station Service Water System,"

CONDITION B, and TS 3.8.1, "AC Sources - Operating," CONDITION B for Comanche Peak Nuclear Power Plant (CPNPP) Units 1 and 2 (Reference 6.1 ).

Vistra OpCo is requesting this one time change for Unit 2, Station Service Water Pump (SSWP) 2-02 replacement at power during Unit 2 Cycle 19, only. New REQUIRED ACTION B.2 provides an 8 day COMPLETION TIME to replace SSWP 2-02 pump. The SSWP 2-02 discharge flow/pressure is degraded.

Replacing the SSWP 2-02 will restore a stable discharge flow/pressure which will provide assurance that SSWP 2-02 will run at optimum performance during the remainder of Unit 2 Cycle 19. This one-time change applies to CPNPP Unit 2 only.

No changes to the CPNPP Final Safety Analysis Report (Reference 6.2) are anticipated as a result of this License Amendment Request (LAR)20-007.

On November 12, 2020, Vistra OpCo participated in a teleconference with the NRC to discuss a proposed license amendment request to make a one-time TS change to replace a Station Service Water Pump at CPNPP Unit 2 (ML20302A269). In advance of the teleconference, Vistra OpCo provided presentation slides for discussion purposes (ML20314A342). The NRC identified several items relevant to the proposed change which are addressed in this LAR.

2.0 DETAILED DESCRIPTION 2.1 System Design and Operation Station Service Water System The SSWS removes heat from the CCWS heat exchangers and from the emergency diesel generators and supplies cooling water to the safety injection and centrifugal charging pump lube oil coolers and the containment spray pump bearing oil coolers. In conjunction with the CCWS, the SSWS supplies cooling water to meet the plant cooling requirements during normal operation, shutdown, and during and after a postulated accident of either unit. The required cooling water is taken from the safe shutdown impoundment (SSI), which is the ultimate heat sink and is designed in accordance with the guidelines in NRC Regulatory Guide 1.27 (Reference 6.3) The SSWS also acts as a backup water supply for the Auxiliary Feedwater System if the Condensate Storage Tank is depleted.

The SSWS consists of two separate and independent full-capacity, safety-related trains. Cross connections between the two trains add operational flexibility to the SSWS. The SSWS cross-connect between the two units provides additional backup cooling capacity, available to response in the event of a total Loss of Station Service Water (LOSSW).

The safety-related trains are redundant in that the components supplied by one train are sufficient to perform the minimum required safety functions. Two full capacity SSWS pumps and two full capacity supply and return headers are provided for each unit. Both pumps normally operate. This provides a continuous cooling water supply to the two redundant safety-related trains.

Enclosure to TXX-20086 Page 3 of 37 The SSWS is vital to plant safety and is provided with redundant components so that no single failure denies cooling to equipment required for safe shutdown.

Equipment necessary for shutdown is supplied with emergency diesel generator power if normal and offsite power sources fail. In this event, at least one SSWS pump per unit is operative within 60 sec from the beginning of LOOP (including emergency diesel generators starting time, sequencing delays, and pump starting time).

Diesel Generators The standby AC Power System is an independent, onsite, automatically starting system designed to furnish reliable and adequate power for Class 1 E loads to ensure safe plant shutdown and standby when preferred and alternate power sources are not available. Four independent diesel generator sets, two per unit, are provided.

Each generator is driven by a single prime mover and is capable of sequentially starting and supplying the minimum power requirements for a OBA or blackout in one unit. The four diesel generators are electrically and physically independent.

Each diesel generator and its associated equipment is located in a separate room with walls designed to protect the diesel generators and associated equipment against an SSE, tornadoes, missiles, and fire.

2.2 Current Technical Specification Requirements The current Technical Specifications proposed to be changed are Limiting Condition for Operation (LCO), 3.7.8 - Station Service Water System.

CONDITION B, "One SSWS train inoperable." causes implementation of REQUIRED ACTION B.1, "Restore SSWS train to OPERABLE status."

with a COMPLETION TIME of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Limiting Condition for Operation (LCO), 3.8.1 - AC Sources - Operating CONDITION B, "One DG inoperable." causes implementation of REQUIRED ACTION B.4, "Restore DG to OPERABLE status." with a COMPLETION TIME of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

The bases for LCO 3.7.8, REQUIRED ACTION B.1 are as follows; "If one SSWS train is inoperable, action must be taken to restore OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. In this Condition, the remaining OPERABLE SSWS train is adequate to pet1orm the heat removal function. However, the overall reliability is reduced because a single failure in the OPERABLE SSWS train could result in loss of SSWS function. Required Action A 1 [Note - this should be 'B. 1' and is corrected in the Attachment 3 markups of LAR 20-007] is modified by two Notes.

The first Note indicates that the applicable Conditions and Required Actions of LCO 3. 8. 1, AC Sources - Operating," should be entered if an inoperable SSWS train results in an inoperable emergency diesel generator. The second Note indicates that the applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops - MODE 4," should be entered if an inoperable SSWS train results in an inoperable decay heat removal train. This is an exception to LCO 3. 0. 6 and

Enclosure to TXX-20086 Page 4 of 37 ensures the proper actions are taken for these components. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time is based on the redundant capabilities afforded by the OPERABLE train, and the low probability of a OBA occurring during this time period."

The bases for LCO 3.8.1, REQUIRED ACTION B.4 are as follows:

"According to Regulatory Guide 1.93 (Ref 6), operation may continue in Condition B for a period that should not exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

In Condition B, the remaining OPERABLE DG and offsite circuits are adequate to supply electrical power to the onsite Class 1 E Distribution System. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a OBA occurring during this period."

2.3 Reason for Proposed Change Replacement of the SSWP 2-02 requires the train to be unavailable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. A 72-hour COMPLETION TIME is insufficient and an 8 day COMPLETION TIME is requested. See Attachment 2, "CPNPP Post-Work Test Guide, Revision 13, Excerpt - Pumps" for a list of the testing that may be required following Station Service Waster Pump (SSWP) 2-02 replacement. Enabling on line maintenance of this magnitude requires extension of the current COMPLETION TIME from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 8 days.

Exigent Circumstances Over several months, CPNPP has been tracking a degrading performance of SSWP 2-02. Prompt short-term actions have been taken within the time permitted in the action statements of TS 3.7.8 and TS 3.8.1. Longer term corrective actions in the form of SSWP 2-02 replacement are planned. This TS amendment would enable CPNPP to proactively replace the SSWP 2-02 and thus avoid the need for either an unnecessary plant transient/shutdown or requesting regulatory relief in the form of a Notice of Enforcement Discretion (NOED) or emergency technical specification amendment. As a large base loaded electricity generator CPNPP Unit 2 output is a vital state and national resource. Provided this license amendment is approved, the current schedule is to replace the SSWP 2-02 at power in Unit 2 Cycle 19 to allow for Unit 2 to take the 8 day outage prior to the Unit 2 outage in the fall of 2021 and before the high load demands of summer 2021. Without this license amendment CPNPP could be forced to shut down Unit 2 and impose an associated grid transient without a compensating increase in the level of quality or nuclear safety. Avoidance of an unnecessary shutdown of CPNPP Unit 2 will limit potential impact on electrical grid stability during the remainder of Cycle 19. In the event of extreme heat and/or severe weather (e.g., a tornado) coupled with an unplanned shutdown of CPNPP Unit 2 due to a failed SSWP 2-02, grid stability would be challenged with the loss of a large base load unit.

Replacement of Unit 2 Train B SSWP 2-02 at power as requested in this LAR will support replacement of Unit 2 Train A SSWP 2-01 which is scheduled in Unit 2 fall 2021 refueling outage. The SSWP 2-02 being removed will be sent to the vendor for refurbishment and then used to replace Unit 2 Train A SSWP 2-01 in

Enclosure to TXX-20086 Page 5 of 37 the Unit 2 fall 2021 refueling outage.

Vistra OpCo initiated dialog with the NRG on a technical specification change and is making a good faith effort to submit this license amendment request in a timely manner following identification of the degrading SSWP 2-02 flow. Vistra OpCo has communicated with the NRG 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 3.7.8 REQUIRED ACTIONS C.1 and C.2 at the expiration of REQUIRED ACTION 8.1 COMPLETION TIME of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and in accordance with TS 3.8.1 REQUIRED ACTIONS G.1 and G.2 at the expiration of REQUIRED ACTION 8.4 COMPLETION TIME of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

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 77 44, 7756 (Mar. 6, 1986). Staff implementing guidance expresses a preference for a license amendment, 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.

2.4 Description of Proposed Change The proposed change to TS 3.7.8 will add a new NOTE for REQUIRED ACTION 8.1 specifying that REQUIRED ACTION B.1 is not applicable to Unit 2 during replacement of the SSWS Pump 2-02 during Unit 2 Cycle 19 add an OR logic connector after REQUIRED ACTION B.1 add a new REQUIRED ACTION 8.2 with associated NOTE specifying a COMPLETION TIME of 8 days that is only applicable on a one-time basis to Unit 2 during replacement of SSWS pump 2-02 during Unit 2 Cycle 19 The proposed change to TS 3.8.1 will renumber REQUIRED ACTION 8.4 to B.4.1 with associated NOTE specifying that REQUIRED ACTION 8.4.1 is not applicable to Unit 2 during replacement of SSWS Pump 2-02 during Unit 2 Cycle 19 add an OR logic connector after REQUIRED ACTION B.4.1 add a new REQUIRED ACTION 8.4.2 with associated NOTE specifying a COMPLETION TIME of 8 days that is only applicable on a one-time basis to Unit 2 during replacement of SSWS Pump 2-02 during Unit 2 Cycle 19 Note that existing REQUIRED ACTION B.1 of TS 3.7.8 has two NOTES that are directed cascades to LCO's 3.4.6 and 3.8.1. All of the Required Actions of LCO 3.4.6 have immediate Completion Times, to either immediately initiate restoration actions or to suspend dilutions and are applicable in MODE 4 (this change will be implemented at power). As such, no changes are required to LCO 3.4.6.

However, since Condition B of LCO 3.8.1 addresses an inoperable diesel generator (DG), a change to the Completion Time for Required Action 8.4 in Condition 8 is required since TS 3.7.8 directs that the DG associated with an inoperable SSWS train likewise be declared inoperable. For all other systems

Enclosure to TXX-20086 Page 6 of 37 supported by SSWS, LCO 3.0.6 is applicable, i.e., "when a supported system LCO is not met solely due to a support system LCO not being met, the Conditions and Required Actions associated with this supported system are not required to be entered. Only the support system LCO ACTIONS are required to be entered.

As such, CPNPP is requesting similar changes to TS 3.7.8 and TS 3.8.1 in support of the one-time SSWP 2-02 replacement.

The proposed changes are shown on CPNPP Technical Specification pages in (marked-up and retyped).

In addition, an information copy of the associated CPNPP Technical Specification Bases pages is provided in Attachment 3 (marked-up and re-typed).

3.0 TECHNICAL EVALUATION

3.1 Deterministic Evaluation 3.1.1 Station Service Water System Design Analysis The design basis of the SSWS is for one SSWS train, in conjunction with the CCW System and a 100%.capacity containment cooling system, to remove core decay heat following a design basis LOCA as discussed in the FSAR, Section 6.2, "Containment Systems." The SSWS is designed to perform its function with a single failure of any active component, assuming the loss of offsite power. (See, Figure 4.1 ).

The Residual Heat Removal System (RHRS) transfers heat from the RCS to the Component Cooling Water System. The time required for this evolution is a function of the time after shutdown. One SSWS train is sufficient to remove decay heat during subsequent operations in MODES 5 and 6. This assumes a maximum SSWS temperature of 102°F occurring simultaneously with maximum heat loads on the system.

NRC Generic Letter 91-13 included recommendations for enhancing the availability of Service Water Systems for multi-unit sites, to address the potential for loss of all Service Water to a particular unit. As part of the response to GL 91-13, cross-connections are provided between trains and between units such that any pump can supply any other pump's required flow.

The SSWS satisfies Criterion 3of1 OCFR50.36(c)(2)(ii). The requirement for cross connections and opposite unit pumps satisfy Criterion 4 of 1 OCFR50.36(c)(2)(ii).

Diesel Generators Design Analysis The safety-related systems are designed with sufficient capacity, independence, and redundancy to ensure performance of their safety functions assuming a single failure. The offsite electrical power system also provides independence and redundancy to ensure an available source of power to the safety-related loads. Upon loss of the preferred power source to any 6.9 kV Class 1 E bus, the alternate power source is automatically connected to the bus and the diesel generator starts should the alternate source not return power to the Class 1 E buses. Loss of both offsite power sources to any 6.9 kV Class 1 E bus, although

Enclosure to TXX-20086 Page 7 of 37 highly unlikely, results in the diesel generator providing power to the Class 1 E bus.

As discussed in Section 2.2 above, two independent diesel generators and their distribution systems are provided for each unit to supply power to the redundant onsite AC Power System. Each diesel generator and its distribution system is designed and installed to provide a reliable source of redundant onsite-generated (standby) AC power and is capable of supplying the Class 1 E loads connected to the Class 1 E bus which it serves (see Attachment 4, Figure 4.2 and Figure 4.3).

3.1.2 Station Service Water System Pump 2-02 Replacement Station service water pump (SSWP) 2-02 was last replaced in October 2012; it is on a nominal replacement schedule of every 7.5 years. Until recently, the pump had exhibited no unusual conditions.

There are two general areas of concern necessitating replacement of the 2-02 station service water pump, low cooling water pressures and reduced flow design margin.

The pump's discharge is used as a source of cooling and lubrication of the pump's packing and column bushings. As bushing wear increases, flow resistance for cooling and lubrication flow decreases, leading to lower pressures at the cooling and lubrication inlet. This low pressure condition provides a control room alarm that operators respond to. Beginning in July 2020, an excessive number of cooling and lubrication line low pressure alarms were received, requiring operators to blowdown supply strainers almost hourly. Consequently, temporary instrumentation has been installed to more closely monitor cooling and lubrication flow/pressure and relieving operators from excessively blowing down strainers. Using a confirm/refute methodology along with input from the original equipment manufacturer, thorough troubleshooting was performed that concluded that worn pump column bushings are the cause of repeated low pressure alarms rather than other possible causes such as instrumentation.

While there is confidence that the pump can perform its specific safety function for the duration of the mission time, pump replacement is recommended to assure long term reliability.

In October 2020, there was a step decrease in pump flow (approximately 2%)

and in pump discharge pressure (approximately 3%). By the nature of the decrease (step rather than gradual), it is expected that the cause is a specific event such as foreign material ingestion, nicked impeller blade, etc. rather than gradual wear. The original equipment manufacturer was contacted and a prompt operability evaluation was completed. While there is confidence that the pump can perform its specified safety function for the duration of its mission time, the pump's design margin is reduced, leaving reduced margin available for future degradation. Replacement of the pump will correct this condition.

The intended replacement pump was removed from the Station Service Water Pump (SSWP) 1-02 station service water pump location during refueling outage Unit 1 refueling outage twenty-one in October 2020 and has been shipped to the original equipment manufacturer for refurbishment to be used in the SSWP 2-02 location. Based on an in-depth inspection already performed, there is a high level of confidence that the pump will be available by the end of 2020 as a

Enclosure to TXX-20086 Page 8 of 37 replacement. Once replaced, the pump removed from the SSWP 2-02 location will be shipped for refurbishment, and planned to be used as a replacement pump for the SSWP 2-01 location during refueling outage Unit 2 refueling outage nineteen in October 2021. Therefore, replacement of the SSWP 2-02 pump in February 2021 is necessary to also support planned replacement of the SSWP 2-01 pump in October 2021.

Table 4.1 in Attachment 4 provides a Service Water Pump and Motor history for Unit 1 and Unit 2. provides photos of SSWP 2-01 replacement in April 2008 (Figures 4.4 and 4.5) and SSW Pump Motor 2-02 (Figure 4.6).

SSWP 2-02 is a large vertical wet pit type component that must be rigged out of tight clearances (See Attachment 4, Figure 4.6).

Disassembly and replacement of the SSWP 2-02 involves a number of major steps to restore 2-02 pump to OPERABLE. The required major steps to replace 2-02 pump are listed below.

Scheduled maintenance activities:

Place clearances Remove roof access panels Disassemble, uncouple, and remove motor Remove and replace pump Align pump and motor Couple pump Complete Alignment Clean/inspect the pump bay Remove clearances Perform post maintenance tests and confirm operability This scope of work cannot be completed within the current 72-hour COMPLETION TIME.

The estimated time from proposed REQUIRED ACTION B.2 entry to having SSWP 2-02 OPERABLE is approximately 8 days which includes margin for contingencies. CPNPP is requesting an 8 day COMPLETION TIME for unforeseen contingencies.

The activities to replace Station Service Water Pump 2-02 compressor have been preplanned and materials will be pre-staged at the Service Water Intake Structure (SWIS).

A complete list of assumptions, inspections, and regulatory commitment (includes compensatory measures and conditions) are provided in Section 3.5.3 and documented in Attachment 1 ).

3.1.3 Compliance and 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.

Enclosure to TXX-20086 Page 9 of 37 Additional details are provided in the Regulatory Evaluation Section 4.0 of this LAR.

3.1.4 Defense in Depth This request proposes one new REQUIRED ACTION B.2, new NOTE, and associated COMPLETION TIME (CT) of 8 days to TS 3.7.8 CONDITION B.2 and one new REQUIRED ACTION B.4.2, new NOTE, and associated CT of 8 days to TS 3.8.1 CO NOTION B.4.2. The purpose of the extended 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 station service water system Train A and Train A EOG are still available to perform their system safety function while in this TS action. The current 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> CT limit of TS 3.7.8 REQUIRED ACTION B.1 and TS 3.8.1 REQUIRED ACTION B.4 is established with the TS Basis to allow sufficient time to effect restoration for the majority of conditions that lead to a station service water system train inoperability. The requested CT extension does not change the likelihood for an initiating event, successful mitigative action, or required operator actions as assumed in the PRA.

The basis underlying the safety function of the station service water system and emergency diesel generator remain unchanged with an extension of the CT. The trains are required to be OPERABLE to ensure the availability after a postulated design basis accident (OBA). Loss of any one train of station service water or emergency diesel generator does not prevent the safety function from being performed. Because of this design feature, the CT extension would not result in the loss of capability to prevent core damage, loss of capability to maintain containment integrity, or loss of capability to mitigate the consequence of an accident. The Train A station service water and Train A EOG are still able to perform their intended safety function as designed. The SSWS cross-connect between the two units provides additional backup cooling capability, available to respond in the event of a total Loss of Station Service Water (LOSSW). The SSW pump on the opposite unit and its associated cross-connects remain operable such that overall reliability of the function is maintained.

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.

CPNPP's TS are not cascaded, however during the extended CT to replace SSWP 2-02, Unit 2 Train B components affected by Unit 2 Train B SSWS being inoperable will be in pull out in accordance with operation procedures (to protect equipment unless cross connections are made to supply SSW from other train or opposite unit).

TS 3.5.2. ECCS - Operating A single train of ECCS is capable of providing core cooling and negative reactivity to ensure that the reactor core is protected after a Design Basis Accident (OBA), assuming no single failure. The ECCS consists of three

Enclosure to TXX-20086 Page 10 of 37 separate subsystems: centrifugal charging (high head), safety injection (SI)

(intermediate head), and residual heat removal (RHR) (low head). Each subsystem consists of two redundant, 100% capacity trains. The ECCS accumulators and the RWST are also part of the ECCS but are not considered part of an ECCS flow path as described by this TS. The ECCS flow paths consist of piping, valves, heat exchangers, and pumps such that water from the RWST can be injected into the RCS following the accidents described in this LCO.

ECCS Train A will be the "protected train" in accordance with station procedures during the extended CT.

TS 3.6.6, Containment Spray System A single train of Containment Spray is capable of supporting the minimum safety functions necessary to provide containment atmosphere cooling to limit post accident pressure and temperature in containment to less than the design values, assuming no single failure. The Containment Spray System is an Engineered Safety Feature (ESF) system. It is designed to ensure that the heat removal capability required during the post-accident period can be attained. The Containment Spray System provides a method to limit and maintain post accident conditions to less than the containment design values.

The Containment Spray System consists of two separate trains of equal capacity, each capable of meeting the design bases. Each train includes two containment spray pumps, spray headers, nozzles, valves, and piping. Each train is powered from a separate ESF bus. Containment Spray System Train A will be the "protected train" in accordance with station procedures during the extended CT.

TS 3.7.5 Auxiliary Feedwater (AFW) System A single train of AFW is capable of supporting the minimum safety functions necessary to automatically supply feedwater to the steam generators to remove decay heat from the Reactor Coolant System upon the loss of normal feedwater supply. The AFW System consists of two motor driven AFW pumps and one steam turbine driven pump configured into three trains. Each motor driven pump provides 100% of AFW flow capacity, and the turbine driven pump provides 200% of the required capacity to the steam generators, as assumed in the accident analysis. The AFW System is capable of supplying feedwater to the steam generators during normal unit startup, shutdown, and hot standby conditions. Auxiliary Feedwater System Train A and the turbine driven AFW pump will be the "protected train" in accordance with station procedures during the extended CT.

TS 3.7.7. Component Cooling Water (CCW) System A single train of CCW is capable of supporting the minimum safety functions necessary to provide a heat sink for the removal of process and operating heat from safety related components during a Design Basis Accident (OBA) or transient. During normal operation, the CCW System also provides this function for various nonessential components, as well as the spent fuel storage pool.

The CCW System is arranged as two independent, full capacity cooling loops (safeguards loops), and has isolable non-safety related components. Each safeguards loop train includes a full capacity pump, heat exchanger, piping,

Enclosure to TXX-20086 Page 11 of 37 valves, and instrumentation. Each safety related train is powered from a separate bus. Component Cooling Water System Train A will be the "protected train" in accordance with station procedures during the extended CT.

See Section 3.1.5 for discussion of CCW cross connections between trains and units.

TS 3.8.9 Distribution Systems -- Operating The AC electrical power subsystem for each train consists of a primary Engineered Safety Feature (ESF) 6.9 kV bus and secondary load centers and 480 and 120 V buses. Each 6.9 kV ESF bus has two separate and independent offsite source of power as well as a dedicated onsite diesel generator (DG) source. Each 6.9 kV ESF bus is normally connected to a preferred offsite source.

After a loss of the preferred offsite power source to a 6.9 kV ESF bus, a slow transfer to the alternate offsite source is accomplished. If the alternate offsite sources are unavailable, the onsite emergency DG supplies power to the 6.9 kV ESF bus. The AC, DC, and AC vital bus electrical power distribution systems are designed to provide sufficient capacity, capability, redundancy, and reliability to ensure the availability of necessary power to ESF systems so that the fuel, Reactor Coolant System, and containment design limits are not exceeded. The following for Train A electrical power sources will be the "protected train" in accordance with station procedures during the extended CT; Offsite power sources (no switchyard work)

Emergency Diesel Generator (Train A) 6.9kV and 480V buses and MCCs Spent Fuel Pool Cooling The Spent Fuel Pool Cooling and Cleanup System provides cooling to remove residual decay heat from the fuel stored in the spent fuel pool and is designed with redundancy and testability to ensure continued heat removal. A purification loop is provided to remove fission product activity.

The cooling portion of this system has two trains consisting of a pump, heat exchanger, and other associated equipment.

The Spent Fuel Pool Cooling will be aligned to provide cooling from available trains in accordance with site procedures.

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

The Station Service Water System Train A remains available during the extended CT. Risk reduction measures are captured as a commitment in Section 3.5.3 and documented in Attachment 1 to minimize potential failure of Station Service Water System Train A.

Loss of Offsite Power (LOOP)

In the event of a Loss of Offsite Power (LOOP), the Station Service Water System Train A power would be available from Train A Emergency Diesel Generator. Risk reduction measures are implemented as commitments to minimize potential for LOOP and failure of Station Service Water System Train A.

Enclosure to TXX-20086 Page 12 of 37 Extended Loss of Offsite Power (LOOP) with failure of Unit 2 Train A Emergency Diesel Generator)

See Section 3.1.5 for a discussion of this scenario (first bullet of NU REG 0800 BTP 8-8 Recommendation).

Heavy Loads The Service Water Intake Structure (SWIS) building is a seismic categOry I structure and the operating deck and safety-related equipment in the SWIS are located above the probable maximum flood (PMF) level. The Mitigating Strategies Flood Hazard Information (MSFHI) Probable Maximum Flood (PMF) was bounded by the discussion in the Flood Hazard Reevaluation Report (FHRR). Therefore, the SWIS will perform its function given the MSFHI PMF (ML17268A147).

The SWIS Crane is located in the SWIS building (See FSAR Figure 1.2-46 in Reference 6.2) and is used to install and maintain four service water pumps. The SWIS crane is an overhead traveling crane with an underhung 7.5 ton capacity hoist.

The SWIS crane is designed to seismic category II (as defined in FSAR Appendix 17A and listed in FSAR Table 17A-1(Reference 6.2)) and classified as a non-nuclear safety component.

The SWIS crane is required to handle occasional non-critical loads and operate during normal operation of the plant including scheduled maintenance. If the Safe Shutdown Earthquake occurs, the load-bearing components, such as girders, wheels and runways are conservatively designed to remain in place with the wheels being prevented from leaving the tracks.

Safe load paths are established as part of the maintenance activity to replace the SSWP 2-02.

3.1.5 Conformance with NUREG 0800 BTP 8-8 Recommendations CPNPP has reviewed NUREG-0800 Branch Technical Position (BTP) 8-8, "Onsite and Offsite Power Sources Allowed Outage Time Extensions" (Reference 6.8). 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.

LAR 20-007 is requesting a one-time extension for EOG COMPLETION TIME, the guidance and recommendations of BTP 8-8 are addressed as noted below:

[1 8t} 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).

The ability of the supplemental source to have the capacity to bring a CPNPP

Enclosure to TXX-20086 Page 13 of 37 unit to safe shutdown (hot shutdown) in case of a loss of offsite power (LOOP) concurrent with a single failure during plant operation (Mode 1) is not a part of the plant design and licensing bases but is only a criterion of 8TP 8-8 for the implementation of the extended DG CT. The information below is provided in response to the 8TP scenario described above.

During the extended COMPLETION TIME, the Unit 2 Train 8 EOG will be declared inoperable and, for purposes of the following assessment, assumed to be non-recoverable. Note the precise recovery actions taken by plant operators in response to the scenarios postulated below would naturally be specific to the given scenario. The information provided herein is focused on the methods available to restore power to the train A safeguards bus to recover a full train of required safe shutdown equipment.

Two major scenario types are considered. The responses to the scenarios types are fundamentally different. As summarized below, the response to a service water deficit is to provide service water (from Unit 1) whereas the response to the absence of power at the Train A safeguards bus is to provide power via the APDGs.

Scenario 1 Considers a postulated LOOP with a concurrent non-mechanistic failure which renders the Unit 2 train A SSW pump inoperable, which results in the need to shut down the otherwise operable Train A EOG.

The plant design includes SSWS cross-tie capability which would permit supply of the Unit 2 Train A SSWS from Unit 1. The estimated time to establish the flowpath is approximately one (1) hour. Once the flowpath is established, Unit 2 can be safely shutdown using a full compliment of Train A equipment. The primary guidance which would be used in this scenario type is contained in existing procedures A8N-501 and SOP-5018.

Scenario 2 Considers a postulated LOOP with a concurrent non-recoverable loss of the Unit 2 Train A EOG (for reasons other than the loss of SSWS).

CPNPP has Alternate Power Diesel Generators (APDGs) dedicated to their respective Unit. The APDGs may be connected to either safeguards 6900 volt bus to supply approximately 3000 kW to the selected bus.

Procedures direct specific loading sequences and are adequate to bring the affected unit to a safe shutdown. In the scenario type under consideration, the Unit 2 APDGs would be aligned to the Train 8 safeguards bus, 2EA2. The estimated time to load the APDGs is approximately one (1) hour.

Once the APDGs are aligned to power the bus, the equipment necessary to achieve and maintain safe shutdown and to bring the plant to a cold shutdown condition would be available to the operators. The primary source of guidance for loading the APDGs is existing procedure SOP-6148.

Enclosure to TXX-20086 Page 14 of 37 As shown above, event mitigation through use of the SSWS Unit-cross-ties or via use of the APDGs constitute different capabilities for different event scenarios. As the scenarios themselves are mutually exclusive (due to the availability of the Train A SSW pump), there are no procedures for simultaneous use of the cross-ties and the APDGs.

CPNPP has procedures which address Component Cooling Water cross-connections between units, however the preferred options would be to pursue cross-connecting the SSW trains or units or use of the APDGS as discussed above.

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 Section 3.5.3 and documented in Attachment 1.

The new proposed REQUIRED ACTION B.4.2 for TS 3.8.1 includes an 8 day COMPLETION TIME (CT) to replace SSW Pump 2-02. The 8 day CT is based on the replacement activities discussed in Section 2.4 of the Enclosure to TXX-20086 (with some margin).

[2nd] 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 3.8.1 REQUIRED ACTION B.4.2 would only be used once for SSWP 2-02 during Unit 2 Cycle 19.

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

CPNPP would not enter the one-time TS 3.8.1 REQUIRED ACTION B.4.2 extended completion time if severe weather conditions are anticipated.

[4th] 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.

See commitment items 7 and 8 in Section 3.5.3.

[5th] 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 items 1 and 2 in Section 3.5.3.

[61hj 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 items 1, 2, and 7 in Section 3.5.3.

Enclosure to TXX-20086 Page 15 of 37

[?fh] 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 item 2 in Section 3.5.3.

A complete list of assumptions, inspections, and regulatory commitment (including compensatory measures and conditions) are discussed in Section 3.5.

3.2 Safety Systems Affected by the Proposed Change The Station Service Water system (SSWS) provides cooling water to the following components:

Component Cooling Water Heat Exchanger - Each of the two CCW safeguards loops consists of cooling to the following:

o Two Containment spray pump seal coolers o One RHR pump seal cooler o

One RHR heat exchanger o

One Containment Spray heat exchanger o One Chilled Water System (nuclear) o Two Control Room air-conditioning condensers (common) o One UPS air-conditioning condenser (common) o One PASS sample cooler (Train A only)

Diesel Generator (DG) Jacket Water Heat Exchanger Safety Injection Pump (SIP) oil cooler Centrifugal Charging Pump (CCP) oil cooler Two Containment Spray Pumps' (CSP) bearing oil coolers Alternate or emergency source of water to Auxiliary Feedwater (AFW) (as a backup if the Condensate Storage Tank is depleted)

The proposed change provides the necessary time to ensure a more stable and reliable SSWP 2-02. The following provides a summary of the components listed in Section 3.1 of this Enclosure.

ABN-501, Station Service Water System Malfunction, provides procedural guidance to align fire protection water to the EGDs, CCW heat exchangers, CCP lube oil coolers, SIP lube oil coolers, and CSP bearing coolers.

Component Cooling Water Heat Exchanger - CCW provides cooling water for the components listed above.

Diesel Generator Jacket Water Heat Exchanger - SSWS removes heat during normal and accident conditions. During a loss of all SSWS, Fire Protection water may be aligned to the jacket water heat exchangers for emergency diesel generators. (See Attachment 4, Figure 4.3)

Safety Injection Pump oil cooler - SSWS provides cooling water during normal and accident conditions. The SIPs are normally in standby during normal conditions. During accident conditions the SIPs are automatically aligned as intermediate-head safety injection pumps.

Centrifugal Charging Pump oil cooler - SSWS provides cooling water during normal and accident conditions. During normal operation the one CCP provides

Enclosure to TXX-20086 Page 16 of 37 charging flow to the Reactor Coolant System (RCS) and seal injection flow to the Reactor Coolant Pump (RCP) seal packages. During accident conditions the CCPs are automatically aligned as high-head safety injection pumps.

Containment Spray Pump bearing oil coolers - SSWS provides cooling water during normal and accident conditions. The Containment Spray Pumps are normally in standby during normal conditions. During accident conditions the CSPs automatically start when a Safety Injection signal is received and will spray containment when containment pressure reaches its high-high value.

3.3 Additional Resources for Safe Shutdown 3.3.1 Alternate Power Diesel Generators Alternate Power Diesel Generators (APDG) are located on site. They are connected to the 6.9kV Safeguards switchgear through a transfer switch and a bus breaker. This capability does not meet technical specification operability requirements for emergency power sources. However, it does contribute to plant safety by providing another source of power. The APGs are available to feed the selected 6.9kV Class 1 E bus. They may be used in the event of loss of offsite power coincident with failure of both onsite Class 1 E Emergency Diesel Generators.

See Section 3.1.5 for further discussion of APDGs.

3.3.2 FLEX Equipment In accordance with 10 CFR 50.155, "Mitigation of beyond-design-basis events,

CPNPP has developed strategies and guidelines to mitigate beyond-design-basis external events from natural phenomena assuming a loss of all ac power concurrent with a loss of normal access to the ultimate heat sink.

In support of the mitigation strategies, equipment and resources are maintained in a FLEX storage building and other locations. The capability exists to supply alternate path of cooling water for AFW pump operation, CST makeup, SSWS restoration, CCW restoration, and Safety Chilled Water System restoration. FLEX uses the Squaw Creek Reservoir.

FLEX strategies were not used in developing the risk insights for extending the COMPLETION TIME. FLEX components could be used if the cause for the loss of the OPERABLE SSWS Train A is all AC power is lost and an ELAP is declared. FLEX equipment is provided in extreme circumstances that are not designed to maintain the ability to restart the units so they would only be used to protect the health and safety of the public.

All credited Phase 2 portable FLEX equipment is stored in the FLEX Equipment Storage Building, located northeast of the Protected Area. The FLEX Equipment Storage Building was designed, constructed and built to protect the equipment from all applicable external hazards. FLEX equipment will not be pre-staged since it would expose the equipment to external hazards.

3.3.3 Loss of Unit 2 Train A and Train B Safety Chillers As noted above in Section 3.1.5, through either utilization of the SSWS Unit-cross-ties or via the APDGs, as appropriate for the particular scenario, the Unit 2

Enclosure to TXX-20086 Page 17 of 37 Train A Safety Chilled Water system would be recovered. Thus, there is no need to establish supplemental room/area/component cooling as was the case for CPNPP License Amendment 175 regarding a one-time revision to Technical Specification 3.7.19, "Safety Chilled Water" (EPID L-2020-LLA-0137 I ML20223A349).

3.4 Supplemental Risk Information The supplemental risk information included in Sections 3.4.1, 3.4.2 and 3.4.3 supports this license amendment request in concluding that the additional Required Actions have a small impact on overall plant risk. Although this request is not based on the criteria of Regulatory Guide (RG) 1.174, "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," risk information and insights are considered in the overall decision-making process and are useful in in the development of effective risk management strategies.

General risk considerations associated with Operations Inspections and the Fire Protection Program are provided in Sections 3.4.4 and 3.4.5.

3.4.1 Probabilistic Risk Assessment Capability and Insights The risk assessment of the proposed CT extension is based on quantitative models for Internal Events, Internal Flooding and Internal Fire, and qualitative assessments for external hazards. The CPNPP models meet the 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 6.7). CPNPP procedures are in place for controlling and updating the models, when appropriate, and for assuring that the models represent the as-built, as-operated plant. The conclusion, therefore, is that the CPNPP PRA models are acceptable for use in providing supplemental risk information for applications, including assessment of proposed TS amendments.

The PRA analysis and calculation for the proposed COMPLETION TIME are presented in Attachment 6. The baseline Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) contributions from the PRA models are provided in Attachment 5. The results show that the risk significance from extending the proposed COMPLETION TIME for an inoperable Station Service Water train from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 8 days is small and by applying risk insights are within regulatory guidance. The total CDF and LERF values are consistent with thresholds referenced in NRC RG 1.17 4, Revision 2 (Reference 6.5) 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 results, when considered with the unquantified benefits of implementing effective risk reduction measures, are consistent with thresholds referenced in RG 1.177, Revision 1 (Reference 6.6). Note that such measures reduce the sources of increased risk, but they are not explicitly credited in the quantitative risk evaluation.

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

Enclosure to TXX-20086 Page 18 of 37 3.4.2 Development and Use of PRA Insights The evaluation for the proposed COMPLETION TIME extension consisted of a review of the impacted plant systems and their safety functions. There are no systems, structures, or components (SSCs) that will change status due to the proposed change. No new accidents or transients will be introduced by the proposed change. No physical changes are being made to any of the systems affected by the COMPLETION TIME extension. The function and operation of these systems will remain the same, as described in the plant design basis.

Protective measures will be taken to ensure that unanticipated compromises to system redundancy, independence, and diversity will not occur during maintenance activities.

The CPNPP Configuration Risk Management Program (CRMP) is established in Technical Specification 5.5.18 (Reference 6.1 ). CPNPP Engineering Evaluation 321(ECE2.15 Log #321), "Station Service Water-One-Time CT Extension,"

provides a description of controls and assessments to preclude the possibility of simultaneous planned outages of redundant trains and ensure system reliability.

Use of PRA Insights associated with this proposed change can be considered to the extent the defense-in-depth principles described in RG 1.177 and RG 1.17 4 are met.

An appropriate balance is maintained for layers of defense in depth. Prevention of core damage depends on the ability to continuously remove decay heat after an initiating event. During the extended COMPLETION TIME of 8 days, if a design basis accident occurred, the operable Station Service water train remains available to provide heat removal for supported equipment needed to mitigate the event. The configuration to be entered decreases the redundancy of the SSW system due to the removal of one of the SSW pumps from service. The reduced redundancy increases the potential for the plant to lose SSW cooling to plant equipment; however, the current plant design and supporting analyses demonstrate that the plant has sufficient capability to prevent and mitigate a loss of SSW.

Defense-in-depth is maintained during the configuration. Compensatory measures are identified to strengthen the level of defense-in-depth and reduce overall risk.

Design features are preserved without an overreliance on programmatic activities as compensatory measures. During the one-time proposed COMPLETION TIME of 8 days, the opposite train will remain operable and capable of performing necessary safety functions, consistent with accident analysis assumptions.

Safety analysis acceptance criteria stated in the FSAR are not impacted by this change. With this proposed change, the operable Station Service water train remains available and does not result in plant operation in a configuration outside the design basis. Programmatic features are limited to those associated with risk management actions described in Section 3.5. These risk reduction measures provide a qualitative risk impact to the PRA analysis and calculation for this proposed change; no quantitative credit was taken in the PRA analysis for any of the proposed risk reduction measures.

Enclosure to TXX-20086 Page 19 of 37 Fire Protection tracking impacts will be reviewed for fire hazards and fire impairments. Transient combustibles and hot work in fire risk-sensitive areas will be limited. Restrictions on work activities will be in place for components that if lost or failed could result in a direct plant trip or transient. The compensatory measures described in Section 3.5 are intended to reduce the potential of risk-significant configurations, however, are not overly relied upon in the PRA analysis for the proposed licensing amendment.

System redundancy, independence, and diversity are appropriately preserved.

The potential for common-cause failures (CCFs) would not increase as there is no change in failure mechanisms associated with the Station Service water COMPLETION TIME change from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 8 days.

3.4.3 Avoidance of Risk Significant Plant Configurations CPNPP plant risk associated with the proposed Station Service Water System COMPLETION TIME extension is determined from RG 1.200, Revision 2 (Reference 6.7) Capability Category II compliant PRA models 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 of Station Service water with protection of associated support functions and mitigating equipment are discussed below.

The dominant risk scenarios associated with unavailability of Station Service water include:

Loss of remaining SSWP with loss of TDAFW Transient events (including Support System Initiating Event/consequential LOOP) leading to plant trip with failure of TDAFW pump Internal flood events leading to induced seal LOCA with loss of mitigating functions Fires in the unaffected SSW related areas, safety related Switchgear Rooms, Diesel Generator Room, Cable Spreading Rooms and Main Control Room leading to abandonment and or induced loss of off-site power The dominant risk contributors with a train of Station Service water out of service were reviewed as documented in CPNPP Engineering Evaluation 321 (ECE 2.15 Log #321), "Station Service Water-One-Time CT Extension." The evaluation includes detailed review of the individual top cutsets and significant basic events to identify risk reduction measures.

The dominant impact of 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 (random or induced) or loss of the remaining SSWP and loss of TDAFW. Random (very small or small) loss of coolant accidents do not contribute significantly to the change in risk for the Station Service water train out of service. Unavailability of a train of MDAFW (due to random failures or loss of supports/room cooling) coupled with the TDAFW pump failures leads to an asymmetric cooling configuration. This configuration results in the loss of

Enclosure to TXX-20086 Page 20 of 37 functionality of the low leakage reactor coolant pump seals leading to induced seal LOCAs.

The PRA analysis assumes average test and maintenance as allowed within TS.

Risk will be lowered as 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 potential for a common cause failure of the remaining available Station Service water train during the CT extension period for an out of service Station Service water train is considered minimal. 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 risk as documented in CPNPP Engineering Evaluation 321 (EGE 2.15 Log #321 ),

"Station Service Water-One-Time CT Extension." Actions include monitoring of those dominant risk-sensitive areas associated with fire scenarios potentially affecting remaining in-service train equipment during the extended CT. These risk reduction measures are being taken at the start of the work activity and prior to exceeding the initial 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of the CT, (see Section 3.5 of this enclosure) to address various configuration risks and sensitivity analyses:

No elective maintenance permitted for the remaining SSWPs (1-01, 1-02 and 2-01). Equipment will be protected, including the corresponding power supplies and cross-ties, for this one-time outage. This supports the maintenance assumptions in the risk analysis.

No elective maintenance permitted for the emergency diesel generators (EDGs 1-01, 1-02, 2-01 and 2-02), 1 E switchgear (2EA 1, 2EA2) or APDGs (2-01, 2-02). Equipment will be protected, including the corresponding power supplies, for this one-time outage. This supports the maintenance assumptions in the risk analysis and also mitigation of a loss of offsite power during the requested CT window.

No elective maintenance activities on the station transformers (XST1 And XST2). Limited switching activities and limited access for CPNPP switchyards and restriction of switching activities in either CPNPP switchyards. This reduces the likelihood of contributing initiators.

No elective maintenance permitted for Component Cooling Water pumps (1-01, 1-02, 2-01 and 2-02). Equipment will be protected, including the corresponding power supplies and cross-ties, for this one-time outage.

This supports the maintenance assumptions in the risk analysis.

No elective maintenance permitted for Auxiliary Feedwater pumps (Motor-driven 2-01 and 2-02; and Turbine-driven 2-01 ), Residual Heat Removal umps (2-01, 2-02) Centrifugal Charging Pumps 2-01, 2-02 or Safety

Enclosure to TXX-20086 Page 21 of 37 Chilled Water components (2-05 and 2-06). Equipment will be protected, including the corresponding power supplies for this one-time outage. This supports the maintenance assumptions in the risk analysis.

Restrictions on work activities that involve components that if lost or failed could result in a direct plant trip or transient. This reduces the likelihood of contributing initiators.

Performance of surveillances, prior to CT entry, for the SSWP (2-01 ), and supported train related components: EOG 2-01, Auxiliary Feedwater pumps (Motor-driven 2-01 and Turbine-driven 2-01) Safety Chilled Water components (2-05, 2-06)

Monitoring for severe weather conditions by control room and security personnel, though not assumed likely based on seasonal conditions, ensures adverse conditions are not anticipated prior to entry into the CT.

In the event of an unforeseen severe weather condition due to rapidly changing conditions, such as severe high winds, a briefing with crew operators will be performed to reinforce operator actions and responses in the event of a loss of offsite power. Fire Risk Management Actions (RMAs) applicable for SSWP 2-02 will be completed per STl-604.05 "ON-LINE FIRE RISK MANAGEMENT" (these actions protect against fire impacting key redundant equipment).

Operations briefings will address the following actions:

On a loss of all Reactor Coolant Pump (RCP) seal cooling, Operations trips RCPs in time to prevent damage to the Shutdown Seals On a post-trip loss of AFW, Operations initiates flow from either the motor-driven feedwater pump (2-01) or the turbine-driven feedwater pump (2-01) to at least one SG prior to reaching dry SG conditions.

On a loss of Unit 2 SSW, Operations opens the crosstie between the units per ABN-501 "STATION SERVICE WATER SYSTEM MALFUNCTION" On a LOOP and coincident failure of EOG 2-01, Operations starts the APG per SOP 6148 "ALTERNATE POWER GENERATOR OPERATION" and aligns to support Train A equipment Prior to entering the extended CT for replacement of SSWP 2-02, an operating crew shift briefing and pre job walkdowns will be conducted to reduce and manage transient combustibles and to alert the staff about the increased sensitivity to fires in the following fire zones. Operating crew shift briefings will continue to be conducted every shift throughout the duration of the CT period.

The listed fire zones were identified based on risk significance in the FPRA results. (The purpose of these walkdowns is to reduce the likelihood of fires in these zones by limiting transient combustibles, ensuring transients, if required to be present, are located away from fixed ignition

Enclosure to TXX-20086 Page 22 of 37 sources and eliminating or isolating potential transient ignition sources, e.g., energized temporary equipment and associated cables).

Fire Zone Fire Zone Description1 FC1UGA Unit 1 Train A SSW Cable Tunnel2 FC1UGB Unit 1 Train B SSW Cable Tunnel2 FC2UGA Unit 2 Train A SSW Cable Tunnel2 FC2SG Unit 2 Train A EOG Safeguards, up to El. 844'2 FC2SI Unit 2 Train B EOG Safeguards, up to El. 844'2 FCEO Main Control Room3 Unit 2 Electrical Equipment Room I Train A FC2SD Switchgear Safeguards El. 810' 6" Unit 2 Remote Shutdown Panel I Train B FC2SE Switchgear Safeguards El. 831' 6" Unit 2 Cable Spreading Room Electrical Control FCEM Bldg. El. 807' Unit 1 Cable Spreading Room Electrical Control FCEN Bldg. El. 807' FCWB Service Water Intake Structure3 UPS Train A I Batteries Electrical Control Bldg.

FCEH Basement UPS Train BI Batteries Electrical Control Bldg.

FCEC Basement FCEA Electrical Control Bldg. El. 792'2 (1) Identification of these areas is described in more detail, including room designations, in the evaluation documented for STl-604.05.

(2) For larger fire zones walkdowns may be focused on specific fire sensitive areas within the larger fire zones.

(3) Walkdowns are judged as not being required for areas with continuous operator occupation (e.g. MGR). Fire Risk Management Actions (RMAs) where they occur may address the need for walkdowns in some of these areas.

Additionally, planned hot work activities in the fire zones identified above will be prohibited during the time within the extended SSWP 2-02 CT. In the event of an emergent issue requiring hot work in one of the listed

Enclosure to TXX-20086 Page 23 of 37 zones, additional compensatory actions will be developed to minimize the risk of fire.

Roving Fire Watch, performed twice shiftly - focused on specific fire sensitive areas of the EOG (2-01); Switchgear (2EA1); Train A UPS (Fire Zone FCEH); MCR/CSR/RSP (Fire Zones FCEO, FCEM, FCEN, FCEH, FCEC); SSWP 2-01 (FCWB, excluding SSWP 2-02 and the area common to service water pumps while occupied for ongoing replacement work).

The actions described above mitigate additional plant risk beyond that directly represented in the extended Station Service Water train CT quantified risk metrics provided in Attachment 6.

3.4.4 Operations Inspections Shiftly Surveillances OPT-102A-7, Revision 30, "Local Shiftly Surveillances" OPT-1028-7, Revision 20, "Local Shiftly Surveillances" Shiftly Tours I Inspections Shiftly Tours I Inspections (OWl-104-18) Operations shiftly inspection guidelines for Perimeter which includes the Station Service Water Structure and pumps.

Shiftly Tours I Inspection (OWl-104-19) Operations shiftly inspection guidelines for Safety Chillers, CCW pumps, CCPs and Spent Fuel Pool Cooling.

Shiftly Tours I Inspection (OWl-104-17 & OWl-104-42) Operations shiftly inspection guidelines for UPS room coolers.

Shiftly Tours I Inspection (OWl-104-21 & OWl-104-43) Operations shiftly inspection guidelines for Safety Injection, Residual Heat Removal, Containment Spray, and Auxiliary Feedwater pumps.

Preplanning I Staging of Materials The activities to replace Station Service Water Pump 2-02 compressor have been preplanned and materials pre-staged at the Service Water Intake Structure (SWIS).

3.4.5 Fire Protection Program Considerations There are two impacts for proposed activity on the CPNPP Fire Protection Program. The first is the impact due to the physical work itself. The second impact is on the Fire Safe Shutdown Analysis (FSSA).

Impact on the FP Program due to Physical Work -

This scope of work is known, understood, and the maintenance activity will have the necessary fire protection considerations included as required by station procedures. It is not anticipated that the replacement of the SSWP 2-02 will require removing either detection for suppression systems from service. If, for unanticipated reasons, suppression and/or detection has to be removed from service, the compensatory measures specified in the CPNPP Fire Protection Report Revision will be implemented.

Enclosure to TXX-20086 Page 24 of 37 CPNPP FP Deviation 1 a in the FPR (Reference 6.2) (ML20226A417 I ML20315A108) addresses a Deviation from 1 OCFR50, Appendix R, Section 111.G.2.b. This Deviation is summarized below.

Redundant safety water pumps and raceways, service water exhaust fans and their associated raceways, service water isolation valves and their associated raceways, branch circuits from redundant Unit 1 MCC's 1 EB4-3 and 1 EB3-3 and Unit 2 MCC's CP2-EPMCEB-08 and CP2-EPMCEB-07 are located in the same fire area.

The justification for this Deviation was based on physical construction features, suppression and detection, documented "NO Storage Area" for transient combustibles, and cable routing.

In NUREG-0797, Supplement No. 12, "Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2," (SSER 12),

the NRC reviewed and accepted the lack of separation between the SSW pumps. Subsequently the Deviation was expanded to include equipment associated with the SSW pumps as listed above, and in NUREG-0797, Supplement No. 21, "Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2," (SSER 21), the NRC concluded that this was acceptable.

The area of the pump replacement activities and surrounding space are relatively congested at the floor level where the physical construction barriers exist and control of transient combustibles will be problematic. To provide protection against a transient fire due to the pump replacement activities, a Full Time fire watch will be provided 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day until the SSWP 2-02 has been returned to service.

Impact on the FSSA due to the Loss of the SSWP 2 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. 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 SSWP 2-02 discussed here.

CPNPP addresses the FSSA impact and risk associated with performing maintenance on FSSA credited components in accordance with NEI guidance.

CPNPP Procedure STl-604.05, "On-Line Fire Risk Management," delineates the application of Fire Risk to the maintenance process and identifies the subject components and requirements to determine and specify compensatory measures (Risk Management Actions - RMAs) when maintenance is being performed on affected FSSA equipment for extended periods. When one of the required active FSSA 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.

At CPNPP the usual risk management action (RMA) practice is to reduce the likelihood of a fire through a series of administrative controls and limitations on plant activities that significantly reduce the potential for a fire in the subject

Enclosure to TXX-20086 Page 25 of 37 locations. These administrative controls include fire watches, limitations on performing Hot Work, and limitations on introduction and storage of transient combustibles.

The Station Service Water System at CPNPP is credited by the FSSA to provide support to ensure acceptable fire safe shutdown system performance. CPNPP will implement the risk mitigating measures that are specified for addressing impact of maintenance on FSSA credited equipment due to the SSWP 2-02 out of service time extension.

Service Water is used in the FSSA to cool the associated EOG, the associated train of CCW, the associated Centrifugal Charging Pump Lube oil cooler, and be a backup supply of auxiliary feedwater when the condensate storage tank is depleted for secondary side cooling. 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 Station Service Water train prior to entry into the proposed 8 day COMPLETION TIME of TS 3.7.8 REQUIRED ACTION B.2:

Provide a Hourly roving fire watch in the Fire Areas of

Concern, Suspend performance of any ongoing "Hot Work" and prohibit the start of any new "Hot Work," in the 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 Fire Areas of concern are those fire areas that credit Train B Station Service Water to achieve Fire Safe Shutdown.

Additional compensatory measures based on PRA risk insights for this activity (not required for FSSA) are discussed in Section 3.5.

A complete list of assumptions, inspections, and regulatory commitment (including compensatory measures and conditions) are provided in Section 3.5 of this Enclosure and regulatory commitment 5966825 is documented in.

3.5 Assumptions, Inspections, and Regulatory Commitment (for PRA, FSSA, and deterministic defense in depth) 3.5.1 Assumptions Average test and maintenance as allowed within TS is assumed for the PRA analysis and calculation results in Attachment 6 including during the proposed CT. Compensatory measures listed below provide a qualitative risk impact to the calculation results; no quantitative credit was taken in the PRA analysis for any of the proposed compensatory measures. The compensatory measures in Section 3.5.3 will be implemented upon entering proposed TS 3.7.8 REQUIRED ACTION B.2. Compensatory shutdown actions for Severe Thunderstorms and Tornado Warnings are not included in Section 3.5.3, as these warnings are transitory in nature and normally do not last long enough to complete a plant shutdown.

Enclosure to TXX-20086 Page 26 of 37 3.5.2 Inspections Summary of Current Routine Inspections Operations Inspections o Shiftly Surveillance OPT-102A-7, Revision 30, "Local Shiftly Surveillances" OPT-102B-7, Revision 20, "Local Shiftly Surveillances" o Shiftly Tours/ Inspection of equipment OWl-104-18, Revision 76, "Perimeter" OWl-104-19, Revision 69, "Auxiliary Building" OWl-104-17, Revision 126, "Unit 1 Turbine Building" OWl-104-42, Revision 116, "Unit 2 Turbine Building" OWl-104-21, Revision 48, "Unit 1 Safeguards Building" OWl-104-43, Revision 49, "Unit 2 Safeguards Building" 3.5.3 Regulatory Commitment 5966825

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 extended CT. This risk reduction measure was selected based on the reliance on offsite power during the extended CT. 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, CPNPP procedure STA-629 "Switchyard Control and Transmission Grid Interface," 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 or response to abnormal or emergency conditions.

2. Posting of Protected Equipment and all discretionary testing and maintenance suspended for the duration of the SSWP 2-02 extended CT.

Additionally, during the extended CT, signs will be placed on the doorways to the equipment, or in case of the in-service startup transformers, boundary signs, and barrier tape, rope, or chains will be installed. These risk reduction measures ensure continued availability of these components for the entire duration of the extended CT.

Station Service Water Pump 1-01, 1-02, 2-01 Emergency Diesel Generator 1-01, 1-02, 2-01, 2-02 1 E switchgear 2EA 1, 2EA2 Alternate Power Generators 2-01, 2-02 Startup Transformer XST1 (Unit 2 Preferred, Unit 1 Alternate)

Startup Transformer XST2 (Unit 1 Preferred, Unit 2 Alternate)

Enclosure to TXX-20086 Page 27 of 37 138 kV and 345 kV Switchyards and Relay House Access (see exception in item 1 above)

Component Cooling Water Pump 1-01, 1-02, 2-01, 2-02 Motor Driven Auxiliary Feedwater Pump 2-01, 2-02 Turbine Driven Auxiliary Feedwater Pump 2-01 Residual Heat Removal Pumps 2-01, 2-02 Centrifugal Charging Pumps 2-01, 2-02 Safety Chiller 2-05, 2-06 Safety Chilled Water Recirculation Pump 2-05, 2-06

3. For Fire Safe Shutdown Analysis (FSSA)

Fire Areas of Concern will have additional restrictions during the extended CT. The Fire Areas of Concern are the areas that credit the affected SSWP 2-02 for achieving FSSA.

Roving fire watch - hourly Suspend ongoing "Hot Work" and prohibit start of any new "Hot Work" Do not introduce any new transient combustibles, or add to any transient combustibles already authorized Area of the pump replacement activities - Full time fire watch 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day

4. For PRA Risk Mitigation Fire Zones will have additional restrictions during the extended CT.

Roving fire watch - twice per shift Suspend ongoing "Hot Work" and prohibit start of any new "Hot Work" Do not introduce any new transient combustibles, or add to any transient combustibles already authorized

5. SSW Pump 2-02 replacement will not be started if severe weather conditions are anticipated.

6. SSW Pump 2-02 replacement will not be started if grid instability conditions are anticipated.

If the grid becomes unstable in accordance with ABN-601, "Response to a 138/345 KV System Malfunction" after entry into TS 3. 7.8 proposed REQUIRED ACTION B.2, and 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> have elapsed then exit TS 3.7.8 proposed REQUIRED ACTION B.2 and enter TS 3.7.8 REQUIRED ACTION C.1 (Be in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) and TS 3.7.8 REQUIRED ACTION C.2 (Be in MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />).

Once grid stability is restored and plant system statuses are verified, TS 3.7.8 REQUIRED ACTIONs C.1 and C.2 will be exited and TS 3.7.8 proposed REQUIRED ACTION B.2 will be re-entered and SSW Pump 2-02 replacement will continue until completed or 8 days from initial entry into TS 3.7.8 proposed REQUIRED ACTION B.2.

Enclosure to TXX-20086 Page 28 of 37 For example:

TS 3.7.8 proposed REQUIRED ACTION 8.2 is entered and SSW Pump 2-02 replacement begins.

73 hours8.449074e-4 days <br />0.0203 hours <br />1.207011e-4 weeks <br />2.77765e-5 months <br /> after entering TS 3.7.8 proposed REQUIRED ACTION 8.2 the ERGOT grid becomes unstable due to degraded voltage or fluctuating frequency.

At that 73 hour8.449074e-4 days <br />0.0203 hours <br />1.207011e-4 weeks <br />2.77765e-5 months <br /> point TS 3.7.8 proposed REQUIRED ACTION B.2 is exited and TS 3.7.8 REQUIRED ACTIONs C.1 and C.2 are entered.

One hour after exit from TS 3.7.8 proposed REQUIRED ACTION B.2 and entry into TS 3.7.8 REQUIRED ACTIONs C.1 and C.2, the ERGOT grid voltage and frequency are restored with no anticipated instabilities.

TS 3.7.8 REQUIRED ACTIONs C.1 and C.2 are exited and TS 3.7.8 proposed REQUIRED ACTION B.2 is re-entered and SSW Pump 2-02 replacement will continue until completed or 8 days from initial entry into TS 3.7.8 proposed REQUIRED ACTION B.2.

7. Prior to entry into TS 3.7.8 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

8. Prior to entry into TS 3.7.8 REQUIRED ACTION B.2, CPNPP will verify the following items and every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter. If any of the following items are not met, and after 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> have elapsed CPNPP will exit TS 3.7.8 REQUIRED ACTIONS B.2 and enter TS 3.7.8 REQUIRED ACTIONS C.1 and C.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 in accordance with ABN-602, Response to a 6900/480V System Malfunction

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 (Train A) Emergency Diesel Generator or the opposite train (Train A) Station Service Water System For example:

Similar to the example described in grid instability above, if TS 3.7.8 REQUIRED ACTIONS C.1 and C.2 are entered due to an item (a, b, c, or d) above not being met and the items are subsequently met, then TS 3.7.8 REQUIRED ACTIONs C.1 and C.2 will be exited and TS 3.7.8 proposed REQUIRED ACTION B.2 will be re-entered and SSW Pump 2-02 replacement will continue until completed or 8 days from initial entry into TS 3.7.8 proposed REQUIRED ACTION B.2.

Enclosure to TXX-20086 Page 29 of 37

9. Prior to entry into TS 3.7.8 REQUIRED ACTION B.2, and at crew shift turnover during the extended CT, Operations briefings will address the following actions:

a. On a loss of all Reactor Coolant Pump (RCP) seal cooling, Operations trips RCPs in time to prevent damage to the Shutdown Seals

b. On a post-trip loss of AFW, Operations initiates flow from either the motor-driven feedwater pump (2-01) or the turbine-driven feedwater pump (2-01) to at least one SG prior to reaching dry SG conditions.

c. On a loss of Unit 2 SSWP 2-01, Operations opens the crosstie between the units per ABN-501 "STATION SERVICE WATER SYSTEM MALFUNCTION"

d. On a LOOP and coincident failure of EOG 2-01, Operations starts the APG per SOP 6148 "ALTERNATE POWER GENERATOR OPERATION" and aligns to support Train A equipment

e. Remind staff of transient combustibles restrictions in items 3.5.3.3 and 3.5.3.4 above 3.6 Evaluations of Safety Margins The design and operation of the Station Service Water System is not altered by this LAR. The COMPLETION TIME on the system currently allowed by CPNPP TS for a time period of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> will be extended to 8 days. The safety analysis acceptance criteria stated in the FSAR are not impacted by this change. The proposed change will not allow plant operation in a configuration outside the design basis. The requirements regarding the Station Service Water System and Emergency Diesel Generator are credited in the accident analysis will remain the same. As such, it can be concluded that safety margins are not impacted by the proposed change. The proposed change involves a COMPLETION TIME extension of the current TS. The systems that are affected during a particular Station Service Water System or Emergency Diesel Generator outage time period are all associated with the train that corresponds to the affected Station Service Water System train or Emergency Diesel Generator train, leaving one train of safety equipment fully operable and capable of performing its safety functions. Preserving the operability of one Station Service Water System train and Emergency Diesel Generator Train A during the extended COMPLETION TIME will maintain the balance among the prevention of core damage, prevention of containment failure, and consequence mitigation.

3.7 Risk Informed Configuration Management Risk will 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. The process governing CRMP is described in Technical Specifications, Section 5.5.18 (Reference 6.1 ).

Enclosure to TXX-20086 Page 30 of 37 3.8 Conclusions The results of the deterministic evaluation provide assurance thatthe 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 probabilistic 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 Station Service Water System train or Emergency Diesel Generator inoperable to 8 days 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 GDF and LERF are small and consistent with the NRG Safety Goal Policy Statement and the thresholds referenced in Regulatory Guides 1.174 and 1.177.

Constraints on concurrent maintenance of other equipment while the Station Service Water System Train B and Emergency Diesel Generator Train B is 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 allow a one-time COMPLETION TIME of 8 days to allow replacement of the Station Service Water System Pump 2-02 during Unit 2 Cycle 19.

A list of assumptions, inspections, compensatory measures, and conditions are provided in Section 3.5 and regulatory commitment 5966825 is described in Section 3.5.3 and documented in Attachment 1.

The proposed TS 3.7.8 REQUIRED ACTION B.2, new NOTE, and COMPLETION TIME and proposed TS 3.8.1 REQUIRED ACTION B.4.2, new NOTE and COMPLETION TIME are consistent with NRG guidance and meet the following principles:

Meets the current regulations Consistent with defense-in-depth philosophy Maintains sufficient safety margins Vistra OpCo concludes with assurance that the systems and equipment required to safely shut down the plant and mitigate the effects of a design basis accident will remain capable of performing their safety functions, with the established assumptions and compensatory measures in place for the proposed COMPLETION TIME. The proposed one-time TS COMPLETION TIME extension is consistent with NRG guidance and meets the principles of current regulations, defense-in-depth philosophy, and maintains sufficient safety margins.

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 NRG regulations, and (3) the issuance of the amendment will not b~e inimical to the common defense and security or to the health and safety of the public.

Enclosure to TXX-20086 Page 31 of 37

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements I Guidance Section 182a of the Atomic Energy Act requires applicants for nuclear power plant operating licenses to include technical specifications as part of the license.

The Commission's regulatory requirements related to the content of the technical specifications are contained in Title 10, Code of Federal Regulations (10 CFR),

Section 50.36, "Technical Specifications," of 10 CFR Part 50 "Domestic Licensing of Production and Utilization Facilities." The technical specification requirements in 10 CFR 50.36 include the following categories: (1) safety limits, limiting safety systems settings and control settings, (2) limiting conditions for operation, (3) surveillance requirements, (4) design features, and (5) administrative controls. The requirements for one station service water system train inoperable are included in the technical specifications in accordance with 10 CFR 50.36(c)(2), "Limiting Conditions for Operation."

As stated in 10 CFR 50.59(c)(1 )(i), a licensee is required to submit a license amendment pursuant to 10 CFR 50.90 if a change to the technical specifications is required. Furthermore, the requirements of 10 CFR 50.59 necessitate that the NRG approve technical specification changes before the changes are implemented. Vistra OpCo's submittal meets the requirements of 10 CFR 50.59(c)(1 )(i) and 10 CFR 50.90.

The proposed changes involve extensions of the affected COMPLETION TIME from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 8 days. The LCOs themselves remain unchanged, as do the required remedial actions or shutdown requirements in accordance with 10 CFR50.36(c). Therefore, the proposed changes are consistent with the current regulations.

General Design Criteria (GDC), as outlined in 10 CFR 50, Appendix A, were considered for the proposed amendment. Although not the direct subject matter of this License Amendment Request, CPNPP will maintain the ability to meet GDC 2, 4, 5, 17, 18, 44, 45, and 46, which are applicable to the Station Service Water System and Emergency Diesel Generator design, with the proposed licensing amendment. The applicable GDCs considered are described below:

GDC-2 Design bases for protection against natural phenomena Structures, systems, and components important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions. The design bases for these structures, systems, and components shall reflect: (1) Appropriate consideration of the most severe of the natural phenomena that have been historically reported for the site and surrounding area, with sufficient margin for the limited accuracy, quantity, and period of time in which the historical data have been accumulated, (2) appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena and (3) the importance of the safety functions to be performed.

Enclosure to TXX-20086 Page 32 of 37 GDC-4 Environmental and Dynamic Effects Design Bases Structures, systems, and components important to safety shall be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents, including loss-of-coolant accidents. These structures, systems, and components shall be appropriately protected against dynamic effects, including the effects of missiles, pipe whipping, and discharging fluids, that may result from equipment failures and from events and conditions outside the nuclear power unit. However, dynamic effects associated with postulated pipe ruptures in nuclear power units may be excluded from the design basis when analyses reviewed and approved by the Commission demonstrate that the probability of fluid system piping rupture is extremely low under conditions consistent with the design basis for the piping.

GDC-5 Sharing of Structures, Systems, and Components Structures, systems, and components important to safety shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units.

GDC-17 Electric Power Systems An onsite electric power system and an offsite electric power system shall be provided to permit functioning of structures, systems, and components important to safety. The safety function for each system (assuming the other system is not functioning) shall be to provide sufficient capacity and capability to assure that (1) specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded as a result of anticipated operational occurrences and (2) the core is cooled and containment integrity and other vital functions are maintained in the event of postulated accidents.

The onsite electric power supplies, including the batteries, and the onsite electric distribution system, shall have sufficient independence, redundancy, and testability to perform their safety functions assuming a single failure.

Electric power from the transmission network to the onsite electric distribution system shall be supplied by two physically independent circuits (not necessarily on separate rights of way) designed and located so as to minimize to the extent practical the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions. A switchyard common to both circuits is acceptable. Each of these circuits shall be designed to be available in sufficient time following a loss of all onsite alternating current power supplies and the other offsite electric power circuit, to assure that specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded. One of these circuits shall be designed to be available within a few seconds following a loss-of-coolant accident to assure that core cooling, containment integrity, and other vital safety functions are maintained.

Provisions shall be included to minimize the probability of losing electric power from any of the remaining supplies as a result of, or coincident with, the loss of

Enclosure to TXX-20086 Page 33 of 37 power generated by the nuclear power unit, the loss of power from the transmission network, or the loss of power from the onsite electric power supplies.

GDC-18 Inspection and Testing of Electric Power System Electric power systems important to safety shall be designed to permit appropriate periodic inspection and testing of important areas and features, such as wiring, insulation, connections, and switchboards, to assess the continuity of the systems and the condition of their components. The systems shall be designed with a capability to test periodically (1) the operability and functional performance of the components of the systems, such as onsite power sources, relays, switches, and buses, and (2) the operability of the systems as a whole and, under conditions as close to design as practical, the full operation sequence that brings the systems into operation, including operation of applicable portions of the protection system, and the transfer of power among the nuclear power unit, the offsite power system, and the onsite power system.

GDC-44: Cooling Water A system to transfer heat from structures, systems, and components important to safety, to an ultimate heat sink shall be provided. The system safety function shall be to transfer the combined heat load of these structures, systems, and components under normal operating and accident conditions.

Suitable redundancy in components and features, and suitable interconnections, leak detection, and isolation capabilities shall be provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available) the system safety function can be accomplished, assuming a single failure.

GDC-45: Inspection of cooling water system The cooling water system shall be designed to permit appropriate periodic inspection of important components, such as heat exchangers and piping, to assure the integrity and capability of the system.

GDC-46: Testing of cooling water system The cooling water system shall be designed to permit appropriate periodic pressure and functional testing to assure (1) the structural and leak tight integrity of its components, (2) the operability and the performance of the active components of the system, and (3) the operability of the system as a whole and, under conditions as close to design as practical, the performance of the full operational sequence that brings the system into operation for reactor shutdown and for loss-of-coolant accidents, including operation of applicable portions of the protection system and the transfer between normal and emergency power sources.

NRC Regulatory Guide 1.93 For a loss of one AC power source, Section C.4 of Regulatory Guide 1.93, Revision 0, "Availability of Electric Power Sources," (Reference 6.4) states in part, "power operation may continue for a total time that should not exceed 72

Enclosure to TXX-20086 Page 34 of 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />." The proposed change does deviate from the NRC guidance "should not exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />" on a one-time basis for Unit 2 Train B Emergency Diesel Generator as supported by Technical Evaluation in Section 3 of the LAR.

Additional inspections and risk reduction measures will be implemented during the extended COMPLETION TIME to minimize the failure of the remaining Unit 2 Train A Emergency Diesel Generator of the opposite train (see Section 3.5.3 for additional information).

NRC Generic Letter (GL) 91-13, "Request for Information Related to the Resolution of Generic Issue 130, 'Essential Service Water System Failures at Multi-Unit Sites,' Pursuant to 10 CFR 50.54(f)"

As part of CPNPP response to GL 91-13, cross-connections were provided between trains and between units such that any pump can supply any other pump's required flow. In the event of loss of service water at a Unit, the other Unit can provide service water. This capability is not changed by this LAR As stated previously, although a train of the Station Service Water System and Emergency Diesel Generator will be inoperable during the extended CT, the opposite train of the Station Service Water System and Emergency Diesel Generator will remain operable. NRC Generic Letter 80-30 states that the specified time to take action when an LCO is not met is a temporary relaxation of the single failure criterion since the completion time provides a limited time to fix equipment or otherwise make it operable.

There are no permanent changes to the design of the Station Service Water System or its supported systems involved with this LAR. The evaluations provided within this proposed amendment confirm that the plant will continue to comply with the applicable design criteria. Additionally, prior to entering proposed TS 3.7.8 REQUIRED ACTION B.2 Restore SSWS train to OPERABLE status CT and TS 3.8.1 REQUIRED ACTION B.4.2 Restore DG to OPERABLE status CT, action will be taken to ensure no discretionary maintenance or discretionary testing is planned for the remaining duration as described in Section 3.5.3.

In this configuration, the operable train will respond as designed during design basis events. The requested period of 8 days to complete the required actions of the affected TS is reasonable considering the redundant capabilities of the above systems, the defense-in-depth measures that will be available, and compensatory measures that will be in place.

4.2 Precedent The U.S. Nuclear Regulatory Commission (the Commission) has issued Amendment No. 191 to Renewed Facility Operating License No. NPF-77 for the Braidwood Station, Unit 2. The amendment allows one train of the Essential Service Water to be inoperable for up to 200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> from the previously allowed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for pump repair (Reference 6.9). This approved LAR from Braidwood is not identical to CPNPP LAR 20-007 in that the Braidwood amendment is risk based whereas the CPNPP requested amendment is deterministic with risk insights. Braidwood is similar to CPNPP in that both are a one-time request.

Enclosure to TXX-20086 Page 35 of 37 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 1 O 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 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 8 days, on a one-time basis for Comanche Peak Nuclear Power Plant Station Service Water System Train B (replacement of Station Service Water System Pump 2-02). This one-time increase will be used once at power during Unit 2 Cycle 19. An additional REQUIRED ACTION, new Note, and associated COMPLETION TIME is specified for Technical Specification (TS) 3.7.8, "Station Service Water System," and TS 3.8.1, "AC Sources - Operating," when Station Service Water System Train B is declared inoperable to replace the Station Service Water Pump 2-02. The proposed changes do not physically alter any plant structures, systems, or components, and are not an accident initiator: therefore, there is no effect on the probability of accidents previously evaluated. As part of the single failure design feature, loss of one Station Service Water System train or one Emergency Diesel Generator does not prevent the minimum safety function from being performed. Also, the proposed changes do not affect the type or amounts of radionuclides released following an accident, or affect the initiation and duration of their release. Therefore, the consequences of accidents previously evaluated, which rely on Station Service Water System or Emergency Diesel Generator to mitigate, are not significantly increased.

Therefore, the proposed changes do 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 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.

Enclosure to TXX-20086 Page 36 of 37

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 insights.

The deterministic evaluation concluded with one inoperable Station Service Water System train and one inoperable Emergency Diesel Generator, the redundant OPERABLE Station Service Water System train and Emergency Diesel Generator will be able to perform the safety function as described in the accident analysis. Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Supplemental risk information supporting this license amendment request concluded that the additional REQUIRED ACTIONs, new NOTEs, and associated COMPLETION TIMEs have a small impact on overall plant risk and is consistent with the NRC Safety Goal Policy statement and the thresholds in Regulatory Guide (RG) 1.174, "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 Station Service Water System and AC Sources Operating will be able to perform their design function with a longer COMPLETION TIME for inoperable Station Service Water System Train B (replacement of Station Service Water System Pump 2-02) and inoperable Emergency Diesel Generator Train B during Unit 2 Cycle 19, 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 proposed 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-20086 Page 37 of 37

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 I ML053180525) 6.2. Comanche Peak Units 1 and 2, Transmittal of Electronic Licensing Basis Documents including Certified FSAR Amendment 110, Dated August 3, 2020 (M L20226A417 /M L20315A055) 6.3. NRC Regulatory Guide 1.27, Revision 2, January 1976, "Ultimate Heat Sink for Nuclear Power Plants" (ML003739969) 6.4. NRC Regulatory Guide 1.93, December 1974, "Availability of Electric Power Sources" (MP003740292) 6.5. 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. (ML100910006) 6.6. NRC Regulatory Guide 1.177, ""An Approach for Plant-Specific, Risk-Informed Decision-making: Technical Specifications," Revision 1, May 2011. (ML100910008) 6.7. 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) 6.8. NRC NUREG 0800 Standard Review Plan, Branch Technical Position (BTP) 8-8 "Onsite (Emergency Diesel Generators) and Offsite Power Sources Allowed Outage Time Extensions (February 2012)

(ML113640138) 6.9. Braidwood Station, Unit 2 - Issuance of Amendments Regarding 2A Essential Service Water Pump Technical Specifications for Pump Repair (CAC No. MF8438) (ML16315A302) to TXX-20086 Page 1 of 1 Regulatory Commitment Number 5966825 Implemented during Unit 2 SSW Pump 2-02 extended COMPLETION TIME Commitment Description Date Number 5966825 Implement the compensatory Upon Implementation of measures listed in Section 3.5.3 the one-time extension of of Enclosure to TXX-20086 completion time for replacement of SSWP 2-02 during Unit 2 Cycle 19 to TXX-20086 CPNPP Post-Work Guide Excerpt Pumps

COMANCHE PEAK NUCLEAR POWER PLANT POST-WORK TEST GUIDE I REVISION NO. 14 I PAGE 23 OF 102 WORK PUMPS disassemble/repair/rework*

bearings 1) 3) 4) 9) 13) 14) 16) 18)

19) couplings **1) 18) seals/packing 4) 7) 8) 11) 12) 13) 15)

16) 17) 19) impeller/shaft/casing 1) 3) 4) 7) 8) 9)

11) 12) 13) 14) 15) 16) 17) 18) 19) wear rings 1) 3) 4) 7) 8) 9) 11) 12) 15)

17) 18) disturb mounting 1) 2) 18)

ASME pump 17)

Reactor Coolant Pumps 5) 6) new installation (or at System Engineer request)

ASME pumps 1-16 (apply as needed), 17) 18) 19)

Non-ASME pumps 1-16 (as needed)

18) 19)

ECCS Subsystems maintenance which drains portions of the system 20)

TDAFWP maintenance which drains pump 21)

See requirements for MOTOR, ELECTRIC CONTROL CIRCUITS.

Exclude PWT requirements for Coupling Inspection/Lubrication type activities REACTOR VESSEL AND INTERNAL COMPONENTS [CJ maintenance/modification of the reactor vessel, vessel internals, or the space between the vessel and the excore detectors that could affect the response of the ex core detectors.

1) disassemble/repair/rework internals 2) welding /metal removal internal surface of pressure boundary 2)

ATTACHMENT A PAGE 15 OF 22 GENERAL TESTING GUIDELINES TESTING ATTRIBUTE Inspection check:

RESPONSIBLE TEST ORGANIZATION (RTO)

1) alignment

1)

MAINT-M MAINT-M MAINT-M MAINT-M QC

2) mounting fastener torque

2)

3) lubrication

3)

4) manual shaft rotation

4)

5) casing internal surfaces (PSI)

5)

6) casing welds and 1/2" of base metal on either side 6)

QC of weld (PSI)

Functional/Operational checks:

7) venting

8) seal injection/seal cooling (as applicable)

9) bearing/oil cooling (as applicable)

10) Deleted

11) suction/discharge pressure

12) adequate mini-flow

13) running current

14) bearing temps

15) gland/packing/seal leakage

16) sample oil if lube capacity >10 gal. after functional test Special tests:

17) ASME test requirements for ASME pumps only, Attachment B-IST

18) Vibration Analysis for pumps in Attachment B-VIB

19) Response time test for pumps listed in Attachment B-TRM

20) Vent ECCS pump casings and accessible discharge piping high points (Reference SR 3.5.2.3 & BASES SR 3.5.2.3)

21) perform post maintenance SOP run

1) lncore/Excore Calibration (Reference SR 3.3.1.6)

Reactor Engineering to determine specific testing requirements.

2) Contact ISi Coordinator in ENGINEERING PROGRAMS

7)

OPS***

8)

OPS***

9)

OPS***

10) Deleted

11) OPS***

12) OPS***

13) MAINT-E

14) OPS*

15) MAINT-M/OPS

16) MAINT-M

17) OPS

18) ZST

19) ZST

20) OPS

21) OPS

• • • Not Post Work Test Step, but a good Operator Fundamenta step

1)

RXE

2)

QC/ENG to TXX-20086 (Total pages including this page - 17)

Technical Specifications - Markup Pages 3.7-21 Insert A 3.8-4 Insert B Technical Specifications - Clean Pages 3.7-21a 3.7-21b 3.8-4a 3.8-4b Technical Specifications Bases - Markup Pages (For Information Only)

B 3.7-41 B 3.7-42 Insert C B 3.8-10 Insert D Technical Specifications Bases - Clean Pages (For Information Only)

B 3.7-41 B 3.7-42 B 3.8-10

ACTIONS (continued)

CONDITION B. One SSWS train inoperable.

Insert A REQUIRED ACTION

---

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

"'--"""~1. Enter applicable Conditions and Required Actions of LCO 3.8.1, "AC Sources -- Operating," for emergency diesel generator made inoperable by SSWS.

2. Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops -- MODE 4," for residual heat removal loops made inoperable by SSWS.

C. Required Action and C.1 Be in MODE 3.

associated Completion Time of Condition A or B AND not met.

C.2 Be in MODE 5.

ssws 3.7.8 COMPLETION TIME 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 36 hours

==::;================:===-=~==-==---=-~--=-=============:;;;=====~=======

COMANCHE PEAK - UNITS 1 AND 2 3.7-21 Amendment No. 4§.G.;. 156

Insert A B.1 ---------------- NOTE --------------------

OR Required Action B.1 is not applicable to Unit 2 during replacement of the SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19.

Restore SSWS train to OPERABLE 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> status B.2 ---------------- NOTE --------------------

Required Action B.2 is applicable on a one-time basis to replace SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19. If Unit 2, Train A SSWS becomes inoperable, immediately enter LCO 3.0.3. Regulatory Commitment 5966825 (Attachment 1 to TXX-20086) will be implemented during the 8 day COMPLETION TIME.

Restore SSWS train to OPERABLE 8 days status

ACTIONS (continued)

CONDITION REQUIRED ACTION B. (continued)

AND Insert B C. Two required offsite circuits C.1

---

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

inoperable.

In MODES 1, 2 and 3, the TDAFW pump is considered a required redundant feature.

AND Declare required feature(s) inoperable when its redundant required feature(s) is inoperable.

AC Sources -- Operating 3.8.1 COMPLETION TIME 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> from discovery of Condition C concurrent with inoperability of redundant required features C.2 Restore one required offsite circuit to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> OPERABLE status.

COMANCHE PEAK - UNITS 1 AND 2 3.8-4 Amendment No. 150

Insert B B.4.1

---

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

Required Action B.4.1 is not applicable to Unit 2 during replacement of the SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19.

Restore DG to OPERABLE status.

72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> OR B.4.2

---

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

Required Action B.4.2 is applicable on a one-time basis to replace SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19. If Unit 2, Train A SSWS becomes inoperable, immediately enter LCO 3.0.3.

Regulatory Commitment 5966825 (Attachment 1 to TXX-20086) will be implemented during the 8 day COMPLETION TIME.

Restore DG to OPERABLE status 8 days

ACTIONS (continued)

CONDITION B. One SSWS train inoperable.

ssws 3.7.8 REQUIRED ACTION COMPLETION TIME

---

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

1. Enter applicable Conditions and Required Actions of LCO 3.8.1, "AC Sources -- Operating," for emergency diesel generator made inoperable by SSWS.

2. Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops -- MODE 4," for residual heat removal loops made inoperable by SSWS.

B. 1 ---------------------N 0 TE--------------------

Req u ired Action B.1 is not applicable to Unit 2 during replacement of the SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19.

Restore SSWS train to OPERABLE 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> status.

COMANCHE PEAK - UNITS 1 AND 2 3.7-21a Amendment No. 150, 156,

ACTIONS CONDITION B. (continued)

C. Required Action and associated Completion Time of Condition A or B not met.

REQUIRED ACTION B. 2 ---------------------NOTE--------------------

Required Action B.2 is applicable on a one-time basis to replace SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19. If Unit 2, Train A SSWS becomes inoperable, immediately enter LCO 3.0.3. Regulatory Commitment 5966825 (Attachment 1 to TXX-20086) will be implemented during the 8 day COMPLETION TIME.

Restore SSWS train to OPERABLE status.

C.1 Be in MODE 3.

AND C.2 Be in MODE 5.

ssws 3.7.8 COMPLETION TIME 8 days 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 36 hours COMANCHE PEAK - UNITS 1 AND 2 3.7-21 b Amendment No. 150, 156,

ACTIONS CONDITION B. (continued)

REQUIRED ACTION AND B. 4.1 -------------------N 0 TE-------------------

Req u ired Action B.4.1 is not applicable to Unit 2 during replacement of the SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19.

AC Sources -- Operating 3.8.1 COMPLETION TIME Restore DG to OPERABLE status. 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> B. 4. 2 -------------------N 0 TE-------------------

Req u ired Action B.4.2 is applicable on a one-time basis to replace SSWS Pump 2-02 (Train B) during Unit 2 Cycle 19. If Unit 2, Train A SSWS becomes inoperable, immediately enter LCO 3.0.3.

Regulatory Commitment 5966825 (Attachment 1 to TXX-20086) will be implemented during the 8 day COMPLETION TIME.

Restore DG to OPERABLE status. 8 days COMANCHE PEAK - UNITS 1 AND 2 3.8-4a Amendment No. 4-W,

ACTIONS (continued)

CONDITION C. Two required offsite circuits C.1 inoperable.

AND REQUIRED ACTION

---

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

1 n MODES 1, 2 and 3, the TDAFW pump is considered a required redundant feature.

Declare required feature( s) inoperable when its redundant required feature(s) is inoperable.

AC Sources - Operating 3.8.1 COMPLETION TIME 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> from discovery of Condition C concurrent with inoperability of redundant required features C.2 Restore one required offsite circuit to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> OPERABLE status.

COMANCHE PEAK-UNITS 1 AND 2 3.8-4b Amendment No. 4eG,

BASES LCO (continued)

APPLICABILITY ACTIONS ssws B 3.7.8

b.

The associated piping, valves, and instrumentation and controls required to perform the safety related function are OPERABLE.

A SSW Pump on the opposite unit is OPERABLE as back-up in the event of a LOSSW if it is capable of providing required flow rates. An emergency diesel generator power source is not required because loss of offsite power is not assumed coincident with a LOSSW event.

A cross-connect valve is OPERABLE if it can be cycled or is locked open. A valve that cannot be demonstrated OPERABLE by cycling is considered inoperable until the valve is surveilled in the locked open position. However, at least one cross-connect valve between units is required to be maintained closed in accordance with GDC-5 unless required for flushing or due to total loss of Station Service Water pumps for either unit.

In MODES 1, 2, 3, and 4, the SSWS is a normally operating system that is required to support the OPERABILITY of the equipment serviced by the SSWS and required to be OPERABLE in these MODES.

In MODES 5 and 6, the OPERABILITY requirements of the SSWS are determined by the systems it supports.

A.1 and A.2 If no SSW pump on the opposite unit or its associated cross-connects are operable, the overall reliability is degraded since a back-up in the event of a Loss of Station Service Water System (LOSSWS) event may not be capable of performing the function. The 7 day completion time is based on the low probability of a LOSSWS during this time period.

• operable, action must be taken to restore OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

• s Condition, the remaining OPERABLE SSWS train is adequate to perform the t removal function. However, the overall reliability is reduced because a single e in the OPERABLE SSWS train could result in loss of SSWS function. Requir ction A.1 is modified by two Notes. The first Note indicates that the applicab nditions and Required Actions of LCO 3.8.1, "AC Sources - Operating," s be entered if an inoperable SSWS train results in an inoperable emergency die (continued)

COMANCHE PEAK-UNITS 1 AND 2 B 3.7-41 Revision79

BASES ACTIONS SURVEILLANCE REQUIREMENTS ssws B 3.7.8 generator. T ond Note indicates that the applicable Conditions and Required Actions of L 4.6, "RCS Loops - MODE 4," should be entered if an inoperable SSWS train resu

• an inoperable decay heat removal train.

This is an exception to LCO 3.0.6 and e es the proper actions are taken for these components. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion

• is based on the redundant capabilities afforded by the OPERABLE train, the low probability of a OBA occurring during this time period.

C.1 and C.2 If the SSWS train or an SSW Pump on the opposite unit and its associated cross-connects cannot be restored to OPERABLE status within the associated Completion Time, the unit must be placed in a MODE in which the LCO does not apply. To achieve this status, the unit must be placed in at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

SR 3.7.8.1 This SR is modified by a Note indicating that the isolation of the SSWS components or systems may render those components inoperable, but does not affect the OPERABILITY of the SSWS.

Verifying the correct alignment for manual, power operated, and automatic valves in the SSWS flow path provides assurance that the proper flow paths exist for SSWS operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since they are verified to be in the correct position prior to being locked, sealed, or secured. This SR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of being mispositioned are in the correct position. This SR does not apply to valves that cannot be inadvertently misaligned, such as check valves.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

(continued)

COMANCHE PEAK - UNITS 1 AND 2 B 3.7-42 Revision79

Insert C B.1 and B.2 Required Actions B.1 and B.2 are modified by two Notes. The first Note indicates that the applicable Conditions and Required Actions of LCO 3.8.1, "AC Sources - Operating," should be entered if an inoperable SSWS train results in an inoperable emergency diesel generator. The second Note indicates that the applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops - MODE 4," should be entered if an inoperable SSWS train results in an inoperable decay heat removal train. This is an exception to LCO 3.0.6 and ensures the proper actions are taken for these components.

If one SSWS train is inoperable, action must be taken to restore OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. In this Condition, the remaining OPERABLE SSWS train is adequate to perform the heat removal function.

However, the overall reliability is reduced because a single failure in the OPERABLE SSWS train could result in loss of SSWS function. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time is based on the redundant capabilities afforded by the OPERABLE train, and the low probability of a DBA occurring during this time period.

The COMPLETION TIME for restoring the inoperable SSWS train to OPERABLE status can be extended to 8 days, on a one time basis for SSWS 2-02 (Train B) pump and motor replacement during Unit 2 Cycle

19. This one-time change regains reliability margin for Unit 2, Train B SSWS. The 8 day completion time is based on a deterministic evaluation supplemented with risk insights.

BASES ACTIONS

!Insert D

~

B.3.1 and B.3.2 (continued)

AC Sources - Operating B 3.8.1 performed. If the cause of inoperability exists on the other DG, the other DG would be declared inoperable upon discovery and Condition E of LCO 3.8.1 would be entered. Once the failure is repaired, the common cause failure no longer exists, and Required Action B.3.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on the remaining DG, performance of SR 3.8.1.2 suffices to provide assurance of continued OPERABILITY of that DG.

In the event the inoperable DG is restored to OPERABLE status prior to completing either B.3.1 or B.3.2, the applicable plant procedures will continue to evaluate the common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> constraint imposed while in Condition B.

According to Generic Letter 84-15 (Ref. 7), 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable to confirm that the OPERABLE DG is not affected by the same problem as the inoperable DG.

During performance of surveillance activities as a requirement for ACTION statements, the air-roll test shall not be performed.

According to Regulatory Guide 1.93 (Ref. 6), operation may continue in Condition B for a period that should not exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

In Condition B, the remaining OPERABLE DG and offsite circuits are adequate to supply electrical power to the onsite Class 1 E Distribution System. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a OBA occurring during this period.

C.1 and C.2 Required Action C.1, which applies when two offsite circuits are inoperable, is intended to provide assurance that an event with a coincident single failure will not result in a complete loss of redundant required safety functions. The Completion Time for this failure of redundant required features is reduced to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> from that allowed for one train without offsite power (Required Action A.2). The rationale for the reduction to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is that Regulatory Guide 1.93 (Ref. 6) allows a Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for two required offsite circuits inoperable, based upon the assumption that two complete (continued)

COMANCHE PEAK - UNITS 1 AND 2 B3.8-10 Revision 76

Insert D The COMPLETION TIME for restoring the inoperable SSWS train to OPERABLE status can be extended to 8 days, on a one time basis for SSWS 2-02 (Train B) pump and motor replacement during Unit 2 Cycle

19. This one-time change regains reliability margin for Unit 2, Train B SSWS. The 8 day completion time is based on a deterministic evaluation supplemented with risk insights.

BASES LCO (continued)

APPLICABILITY ACTIONS ssws B 3.7.8

b.

The associated piping, valves, and instrumentation and controls required to perform the safety related function are OPERABLE.

A SSW Pump on the opposite unit is OPERABLE as back-up in the event of a LOSSW if it is capable of providing required flow rates. An emergency diesel generator power source is not required because loss of offsite power is not assumed coincident with a LOSSW event.

A cross-connect valve is OPERABLE if it can be cycled or is locked open. A valve that cannot be demonstrated OPERABLE by cycling is considered inoperable until the valve is surveilled in the locked open position. However, at least one cross-connect valve between units is required to be maintained closed in accordance with GDC-5 unless required for flushing or due to total loss of Station Service Water pumps for either unit.

In MODES 1, 2, 3, and 4, the SSWS is a normally operating system that is required to support the OPERABILITY of the equipment serviced by the SSWS and required to be OPERABLE in these MODES.

In MODES 5 and 6, the OPERABILITY requirements of the SSWS are determined by the systems it supports.

A.1 and A.2 If no SSW pump on the opposite unit or its associated cross-connects are operable, the overall reliability is degraded since a back-up in the event of a Loss of Station Service Water System (LOSSWS) event may not be capable of performing the function. The 7 day completion time is based on the low probability of a LOSSWS during this time period.

B.1 and B.2 Required Actions B.1 and B.2 are modified by two Notes. The first Note indicates that the applicable Conditions and Required Actions of LCO 3.8.1, "AC Sources - Operating," should be entered if an inoperable SSWS train results in an inoperable emergency diesel generator. The second Note indicates that the applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops - MODE 4," should be entered if an inoperable SSWS train results in an inoperable decay heat removal train. This is an exception to LCO 3.0.6 and ensures the proper actions are taken for these components.

(continued)

COMANCHE PEAK-UNITS 1 AND 2 B 3.7-41 Revision TBD

BASES ACTIONS (continued)

SURVEILLANCE REQUIREMENTS ssws B 3.7.8 If one SSWS train is inoperable, action must be taken to restore OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. In this Condition, the remaining OPERABLE SSWS train is adequate to perform the heat removal function. However, the overall reliability is reduced because a single failure in the OPERABLE SSWS train could result in loss of SSWS function. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time is based on the redundant capabilities afforded by the OPERABLE train, and the low probability of a OBA occurring during this time period.

The COMPLETION TIME for restoring the inoperable SSWS train to OPERABLE status can be extended to 8 days, on a one time basis for SSWS 2-02 (Train B) pump and motor replacement during Unit 2 Cycle 19.

This one-time change regains reliability margin for Unit 2, Train B SSWS.

The 8 day completion time for action B.2 is based on a deterministic evaluation supplemented with risk insights.

C.1 and C.2 If the SSWS train or an SSW Pump on the opposite unit and its associated cross-connects cannot be restored to OPERABLE status within the associated Completion Time, the unit must be placed in a MODE in which the LCO does not apply. To achieve this status, the unit must be placed in at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

SR 3.7.8.1 This SR is modified by a Note indicating that the isolation of the SSWS components or systems may render those components inoperable, but does not affect the OPERABILITY of the SSWS.

Verifying the correct alignment for manual, power operated, and automatic valves in the SSWS flow path provides assurance that the proper flow paths exist for SSWS operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since they are verified to be in the correct position prior to being locked, sealed, or secured. This SR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of being mispositioned are in the correct position. This (continued)

COMANCHE PEAK - UNITS 1 AND 2 B 3.7-42 Revision TBD

BASES ACTIONS B.3.1 and B.3.2 (continued)

AC Sources - Operating B 3.8.1 performed. If the cause of inoperability exists on the other DG, the other DG would be declared inoperable upon discovery and Condition E of LCO 3.8.1 would be entered. Once the failure is repaired, the common cause failure no longer exists, and Required Action B.3.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on the remaining DG, performance of SR 3.8.1.2 suffices to provide assurance of continued OPERABILITY of that DG.

In the event the inoperable DG is restored to OPERABLE status prior to completing either B.3.1 or B.3.2, the applicable plant procedures will continue to evaluate the common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> constraint imposed while in Condition B.

According to Generic Letter 84-15 (Ref. 7), 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable to confirm that the OPERABLE DG is not affected by the same problem as the inoperable DG.

During performance of surveillance activities as a requirement for ACTION statements, the air-roll test shall not be performed.

B.4.1 According to Regulatory Guide 1.93 (Ref. 6), operation may continue in Condition B for a period that should not exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

In Condition B, the remaining OPERABLE DG and offsite circuits are adequate to supply electrical power to the onsite Class 1 E Distribution System. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a OBA occurring during this period.

B.4.2 The COMPLETION TIME for restoring the inoperable SSWS train to OPERABLE status can be extended to 8 days, on a one time basis for SSWS 2-02 (Train B) pump and motor replacement during Unit 2 Cycle19.

This one-time change regains reliability margin for Unit 2, Train B SSWS.

The 8 day completion time is based on a deterministic evaluation supplemented with risk insights.

C.1 and C.2 Required Action C.1, which applies when two offsite circuits are inoperable, is intended to provide assurance that an event with a coincident single failure (continued)

COMANCHE PEAK - UNITS 1 AND 2 B 3.8-10 Revision TBD to TXX-20086 Supporting Tables and Figures For LAR 20-007

{For Information Only)

Table 4.1 Service Water Pump & Motor History Figure 4.1 Station Service Water System - Unit 2 Figure 4.2 6.9 kV I 480 VI Switchyard (Unit 1 - Typical)

Figure 4.3 Emergency Diesel Jacket Water Simplified Drawing Figure 4.4 SSW Pump 2-01 Replacement (April 2008)

Figure 4.5 SSW Pump 2-01 Replacement (April 2008)

Figure 4.6 SSW Pump Motor 2-02

Table 4.1 Service Water Pump & Motor History Last Recommended Current Component Replacement Scheduled Performance Issues Replaced Frequency Replacement 1-01 SWP April 2016 7.5 years April 2025 No known performance issues 1-02 SWP Oct 2020 7.5 years Oct 2029 Newly installed pump; no known performance issues 2-01 SWP April 2008 7.5 years Oct 2021 See NOTE 1 below.

2-02 SWP Oct 2012 7.5 years Feb 2021 July 2020 - seal & cooling water low pressure alarms October 2020 - experienced reduced flow margin Temporary seal and lubrication water pressure and flow instrumentation has been installed 1-01 SWP Motor Oct 2011 9 years or April 2022 No known performance issues; scheduled due to service life condition based 1-02 SWP Motor Oct 2020 9 years or TBD Newly installed motor; no known performance issues condition based 2-01 SWP Motor April 2008 9 years or Oct 2021 No known performance issues; scheduled due to service life condition based 2-02 SWP Motor Oct 2012 9 years or TBD No known performance issues condition based NOTE 1 The 2-01 station service water pump was last replaced in April 2008 and replacement is scheduled for October 2021.

Although Comanche Peak replaces service water pumps on a nominal 7.5 year frequency, the original equipment manufacturer does not recommend a specific frequency. Replacement deferral had been thoroughly reviewed in a formal evaluation. Low cooling and lubrication alarms are received more frequently than normally expected; however, the pump's flow/pressure performance has been steady with no indications of problems. Pump motor loading and temperatures are normal, revealing no obvious problems with pump performance. Mitigation strategies were identified in the event the number of cooling and lubrication water low pressure alarms becomes excessive. It was concluded that the pump's expected operation would be acceptable for an additional operating cycle.

Figure 4.1 Station Service Water System - Unit 2 PT SSW Pump N

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PT SSW Pump 2-02 FE FT

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SCREEN WASH PUMP X-01 SCREEN WASH PUMP Die-I Generator Jacket Water Cooler FE FT Unit 1 B

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-0 2

__.____.STATION SERVICE WATER SYSTEM Unit 2

Figure 4.2 - 6.9 kV I 480 V (Unit 1 - typical) 345kV Switc:hyartl 345kV Switchyartl 345kV 345kV 345kV swttc:hyartl Swi!Cllyartl 1MT1~ 1MT2 I

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y lhere are Iola! of 6 removable links per Transformer (1/phase of the X Winding and 1/phase of the Y Winding).

GD Removable Link U2 safeguartls Susses Alternate

Figure 4.3 - Emergency Diesel Jacket Water Simplified Drawing Return from Cylinder Jackets Diesel Exhaust Jacket Flowpath shown is based u on the diesel runnin.

Emergency Diesel Jacket Water Simplified Drawing Return from Cylinder Jackets Diesel Exhaust Jacket Governor Engine Driven Cooler Jacket Water Pump -

JW Temperature Control Valve Return from Governor Cooler Auxiliary Jacket Water Pump

.... -oa---.~~~~---1 SSW SSW Floor Drain Drain valve Lube Oil Cooler Keep Warm Pump Chem Add Pot Demin Water

Figure 4.4 - SSW Pump 2-01 Replacement (April 2008)

Figure 4.5 - SSW Pump 2-01 Replacement (April 2008) r I

Figure 4.6 - SSW Pump Motor 2-02 to TXX-20086 Page 1of5 Baseline PRA Model Average Annual CDF /LERF Table 1: Baseline PRA Model Average Annual CDF /LERF1 Hazards Unit2CDF Unit2 LERF (per year)

(per year)

Internal Events and Internal i.25E-06 i.12E-07 Flooding Internal Fire 5.02E-05 6.68E-o6 Total 5.14E-052 6.79E-063 Table Notes:

1.

The contribution of High Winds to baseline CDF / LERF values was evaluated qualitatively; risk from this hazard is small compared to other events based on plant design and low likelihood of occurrence of a significant wind event due to the time frame of the extended CT and prior confirmation of the long range forecast.

2. Total CDF meets the RG i.174 acceptance criteria of < 1E-4 per year

3. Total LERF meets the RG i.174 acceptance criteria of< 1E-5 per year A5 References

1.

Engineering Evaluation 321, "Station Service Water - One-Time CT Extension"

2. NRC Regulatory Guide i.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities," Revision 2, March 2009.

(ML090410014)

3. CPNPP received NRC approval for the Surveillance Frequency Control Program on June 29, 2012 (ML12067A244)

As.1 Technical Adequacy of the PRA The CPNPP PRA model is sufficiently robust and suitable for use in risk informed processes such as for regulatory decision making. The peer reviews that have been conducted and the resolution of findings from those reviews demonstrate that the internal events, internal flooding and fire models of the PRA have been performed in a technically correct manner. The assumptions and approximations used in development of the PRA have also been reviewed and are appropriate for their application.

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 to TXX-20086 Page 2 of 5 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.

PRA Acceptability 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 which quantify Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) due to internal events, including internal flooding, at power. The 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 2). 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 3 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.

In 2018, an independent assessment was performed to review actions taken by CPNPP to close out the open internal events F&Os. The assessment followed the process documented in Appendix X to NEI 05-04. All finding level internal events F&O dispositions and identified suggestion F&Os were determined to have been adequately addressed and are now considered CLOSED and no longer relevant to the PRA model. 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.

to TXX-20086 Page 3 of 5 The baseline CDF and LERF for the internal events and internal flooding model are provided in the table above [see Engineering Evaluation 321, Summary of Results section, Table 1].

Fire Hazards This one-time Technical Specification change evaluation includes results from the 2019 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 methodology with no exceptions. 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 revised to incorporate updated industry information and applicable FAQs. The current Comanche Peak Fire PRA model has been developed, documented and reviewed with reference to RG i.200, Revision 2, Capability Category II standards (Reference 2).

Following a model revision, an independent assessment was performed in 2018 to review actions taken by CPNPP to close out the open fire F&Os. The assessment followed the process documented in Appendix X to NEI 05-04. All finding level fire F&O dispositions were determined to have been adequately addressed and are now considered CLOSED and no longer relevant to the PRA model.

The baseline CDF and LERF for the internal fire are provided the table above [see Engineering Evaluation 321, Summary of Results section, Table 1].

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 Station Service water system and its supports are in Category I seismic structures, they are assumed to not be damaged (total failure) in the seismic event. The change in risk associated with a train of Station Service water 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 8 day extended CT is considered small, and when considering that a train of safety related equipment would remain available, the overall change in risk due to the extended CT can be considered small. Updated seismic hazard information was reviewed in Engineering Evaluation 321 (Reference 1) and determined the IPEEE to TXX-20086 Page 4 of 5 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 321 (Reference 1) to evaluate other external events for risk impact associated with the requested extension to the Station Service water 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.

IPEEE results were considered as part of the qualitative evaluation for the extended CT. The high wind PRA recently developed provides quantitative results and walkdown insights that confirm the IPEEE insights and conclusions.

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 explained by 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 1 of this submittal), the change in tornado risk as discussed above is considered to be small. The IPEEE concluded that the significant contribution from this hazard was due to the lower range of high wind events. The likelihood of a tornado strike at CPNPP was estimated to be 5.oE-04 annually. The likelihood of a high wind event to occur during the one-time extended CT duration is relatively small (~i.09E-04, IPEEE) for a wind event during the 8-day CT) and major mitigating systems are not directly affected by the wind event. 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.

As.2 PRA Uncertainty Evaluations The review of generic and plant specific sources of uncertainty for the baseline models is documented in Reference 1. The sensitivity studies were adequate to address uncertainty associated with this application, including the uncertainty evaluated with respect to room heat-up calculations. Parametric uncertainties were examined using standard statistical error propagation techniques and CDF to TXX-20086 Page 5 of 5 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.

to TXX-20086 Page 1of1 PRA Analysis for one-time Technical Specification Change Table 1: ICCDP and ICLERP for One-Time Technical Specification Change

- CP2-SWAPSW-02 Results1 Hazards DeltaCDF ICCDP DeltaLERF ICLERP (per year)

(CT)

(per year)

(CT)

Internal Events and i.46E-06 i.46E-06 7.54E-08 7.54E-08 Internal Flooding Internal Fire i.35E-06 i.35E-06 L82E-08 i.82E-08 Total 2.81E-06 2.81E-062 9.35E-08 9.35E-08s Table Notes:

1.

Results are based on assumed equipment unavailability set to the average test and maintenance and defined protected train alignments (i.e., no T&M allowed on protected train equipment or the TDAFWpump)

2. Total ICCDP meets the RG 1.177 acceptance criteria of< 1E-5 per year with the benefit of effective compensatory measures implemented to reduce the sources of increased risk (not credited in the quantitative risk evaluation)

3. Total ICLERP meets the RG 1.177 acceptance criteria of< 1E-6 per year with the benefit of effective compensatory measures implemented to reduce the sources of increased risk (not credited in the quantitative risk evaluation)

4. The risk impact to the opposite unit from reduced availability of the crosstie was evaluated separately and was found to be non-risk significant with ICCDP and ICLERP results on the order of E-B and E-9, respectively Table

References:

1.

Regulatory Guide i.177, An Approach for Plant-Specific, Risk-Informed Decisionmaking:

Technical Specifications, Revision 1, dated May 2011

2. Engineering Evaluation 321, "Station Service Water - One-Time CT Extension"