NL-24-0286, Emergency Request to Revise Technical Specification 3.7.9 for a One-Time Change to Support a Unit 1 Nuclear Service Cooling Water Transfer Pump Repair

Emergency Request to Revise Technical Specification 3.7.9 for a One-Time Change to Support a Unit 1 Nuclear Service Cooling Water Transfer Pump Repair

ML24202A001
Person / Time
Site:	Vogtle
Issue date:	07/20/2024
From:	Coleman J Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-24-0286
Download: ML24202A001 (1)

Text

Reg u lat o ry Af f airs 3535 Colonnade Parkway Birmingham, AL 35243

Tel 205.992.5000

J uly 20, 2024 N L-24-0286 10 C FR 50.90

D oc k et N os.: 50-424

U. S. N uc lear R egulatory C om m ission ATTN: Doc um ent Control Desk Washington, D. C. 20555-0001

Vogtle Electric G enerating Plant Unit 1 Emergency Request to Revise T echnical Specification 3.7.9 for a O ne-T ime Change to Support a Unit 1 Nuclear Service Cooling Water T ransfer Pump Repair

Pursuant to 10 C FR 50.90 and 10 C FR 50.91(a)(5), Southern N uc lear O perating C om pany (SN C ) hereby requests an em ergenc y am endm ent to Vogtle Elec tric G enerating Plant (VEG P)

U nit 1 renew ed f ac ility operating lic ense (R FO L) N PF-68. The proposed c hange w ould rev ise Tec hnic al Spec if ic ations (TS) Lim iting C ondition f or O peration (LC O ) 3.7.9, U ltim ate H eat Sink (U H S), suc h that a 92-day C om pletion Tim e is allow ed f or R equired Ac tion D.2 f or an inoperable N uc lear Serv ic e C ooling Water (N SC W) basin transf er pum p. The TS c hanges w ould be a one-tim e c hange and in ef f ec t only during Vogtle U nit 1 C y c le 25. The c hange also inc ludes a R equired Ac tion D.2 N ote w hic h prev ents applic ation of LC O 3.0.4.a and b f or entry into M O D E 4 f ollow ing 1R 25 unless the 1A N SC W transf er pum p repairs hav e been c om pleted.

The proposed em ergenc y am endm ent is requested bec ause the 1A N SC W transf er pum p is inoperable and w ill lik ely not be dec lared O PER ABLE until af ter the ex piration of the c urrent R equired Ac tion and assoc iated C om pletion Tim e of TS 3.7.9 C ondition D, upon w hic h tim e C ondition F w ould be entered. TS 3.7.9 C ondition F requires the plant to be in M O D E 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in M O D E 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The repair of the 1A N SC W transf er pum p is in progress.

SN C requests approv al of the proposed lic ense am endm ent on an em ergenc y basis by J uly 24, 2024, to av oid entry into TS 3.7.9 C ondition F. The proposed c hange w ould be ef f ec tiv e im m ediately upon issuanc e of the am endm ent.

The Enc losure prov ides the desc ription, tec hnic al ev aluation, regulatory ev aluation (inc luding the Signif ic ant H azards C onsideration D eterm ination) and env ironm ental c onsiderations f or the proposed c hange. Attac hm ent 1 c ontains the m ark ed-up TS page, Attac hm ent 2 prov ides the c lean-ty ped TS page, and Attac hm ent 3 prov ides the m ark ed-up TS Bases pages (f or inf orm ation only ).

This letter c ontains no regulatory c om m itm ents. This letter has been rev iew ed and determ ined not to c ontain sec urity -related inf orm ation.

In ac c ordanc e w ith 10 C FR 50.91, a c opy of this applic ation, w ith enc losures, is being prov ided to the designated State of f ic ial(s).

U. S. Nuclear Regulatory Commission N/ 0286 Page 2

If y ou hav e any questions, please c ontac t M r. R y an J oy c e at (205) 992-6468.

I dec lare under penalty of per jury that the f oregoing is true and c orrec t.

Ex ec uted on the 20th day of J uly 2024.

R espec tf ully subm itted,

J am ie M. C olem an D irec tor, R egulatory Af f airs Southern N uc lear O perating C om pany

Enclosure Ev aluation of Proposed C hange

cc: NRC Regional Adm inistrator, R egion ll NRR Project Manager - Vogtle 1 

Senior Resident Inspector - Vogtle 1 

State of G eorgia Env ironm ental P rotec tion D iv ision D oc um ent Serv ic es R TYPE: C VC 7000 Enclosure to NL-24-0286 Evaluation of Proposed Change

Enclosure to NL-24-0286 Evaluation of Proposed Change

1.

SUMMARY

DESCRIPTION

2. DETAILED DESCRIPTION 2.1. System Description 2.2. Current Technical Specifications Requirements 2.3. Need for Emergency Change 2.4. Description of the Proposed Change

3. ENGINEERING ANALYSIS 3.1. Defense in Depth 3.2. Safety Margins 3.3. Compensatory Measures 3.4. Maintenance Rule Control 3.5. Risk

4. REGULATORY EVALUATION 4.1. Applicable Regulatory Requirements/Criteria 4.2. Precedent 4.3. No Significant Hazards Consideration Determination Analysis 4.4. Conclusions

5. ENVIRONMENTAL CONSIDERATION

Attachments

1. Technical Specification Marked-up Pages

2. Revised Technical Specification Pages

3. Technical Specifications Bases Marked-up Pages (for information only)

Enclosure to NL-24-0286 Evaluation of Proposed Change

1.0 Summary Description

Pursuant to 10 CFR 50.90 and 10 CFR 50.91(a)(5), Southern Nuclear Operating Company (SNC) hereby requests an emergency amendment to Vogtle Electric Generating Plant (VEGP)

Unit 1 renewed facility operating license (RFOL) NPF-68. The proposed change would revise Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.7.9, Ultimate Heat Sink (UHS), such that a 92-day Completion Time is allowed for Required Action D.2 for an inoperable Nuclear Service Cooling Water (NSCW) basin transfer pump. The TS changes would be a one-time change and in effect only during Vogtle Unit 1 Cycle 25. The change also includes a Required Action D.2 Note which prevents application of LCO 3.0.4.a and b for entry into MODE 4 following 1R25 unless the 1A NSCW transfer pump repairs have been completed.

The proposed emergency amendment is requested because the 1A NSCW transfer pump is inoperable and will likely not be declared OPERABLE until after the expiration of the current Required Action and associated Completion Time of TS 3.7.9 Condition D, upon which time Condition F would be entered. TS 3.7.9 Condition F requires the plant to be in MODE 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The repair of the 1A NSCW transfer pump is in progress.

2.0 Detailed Description

2.1 System Description

The NSCW transfer pump is a column type design which is over 80 feet in length. There are 8 pairs of seismic restraint pins spaced along the length of the pump. These pins fit into matching loops embedded into the wall of the NSCW tower basin. The alignment of these pins is so precise that the pump column mating flanges are line scribed (match marked) prior to disassembly so that when the columns are reassembled the pins and loops realign. Even with this precaution, divers are sometimes required to enter the water, loosen the column bolts, shimmy the pin into the loop and then retighten the column bolts. The 8 pairs of seismic pins are approximately 180 degrees apart on their respective flanges. When the pumps were installed more than 35 years ago, the mating loops to the seismic pins were welded to the basin walls with the existing pump in place. Because of this custom fit, each pump is unique to its own basin and as a result removal and replacement is challenging.

The NSCW system provides cooling water for the containment coolers, control building essential chiller condensers, various engineered safety features (ESF) pump coolers, standby diesel generator jacket water coolers, and the component cooling water (CCW) and auxiliary component cooling water (ACCW) heat exchangers. The NSCW system transfers the heat removed from these systems to the UHS. The UHS consists of the NSCW mechanical draft cooling towers. Two 100-percent capacity redundant NSCW towers are provided for each generating unit, with one tower associated with each train of the NSCW system. Each NSCW tower consists of a basin containing the UHS water and an upper structure in which the NSCW heat loads are transferred to the atmosphere. The combined storage capacity of the two tower basins per unit provide sufficient cooling for at least 30 days, with no makeup water, assuming two-train operation for 1 day and single-train operation for the remaining 29 days. The design is based upon maximum conditions of dry and wet bulb temperatures as they affect peak basin temperature, tower evaporation losses and basin capacity.

E-2 Enclosure to NL-24-0286 Evaluation of Proposed Change

The UHS provides a heat sink for process and operating heat from safety-related components during a transient or accident, as well as during normal operation. This is done by utilizing the NSCW system and the CCW system. Each redundant NSCW tower consists of a basin that contains the UHS water supply and an upper structure that contains four individual fan spray cells where the heat loads are transferred to the atmosphere. Each spray cell contains one safety-related temperature-controlled fan. Instrumentation is provided for monitoring basin level and water temperature. The tower basins each contain a safety-related transfer pump to permit the use of the combined storage capacity of the basins. The combined storage capacity of two tower basins provides greater than a 30-day cooling water supply assuming the worst combination of meteorological conditions and accident heat loads which maximize the tower heat load, basin temperature, and evaporative losses.

2.2 Current Technical Specification Requirements

TS 3.7.9 requires the UHS to be OPERABLE in Modes 1, 2, 3, and 4. SR 3.7.9 requires verification of the NSCW basin transfer pumps in accordance with the Inservice Testing Program.

The LCO 3.7.9 Bases state that the UHS is required to be OPERABLE and is considered OPERABLE if it contains a sufficient volume of water at or below the maximum temperature that would allow the NSCW to operate for at least 30 days following the design basis loss of coolant accident (LOCA) without the loss of net positive suction head (NPSH) and without exceeding the maximum design temperature of the equipment served by the NSCW. In order to meet these requirements, two NSCW tower basins are required OPERABLE with the following:

1. Basin water level must be 80.25 feet as measured from the bottom of the basin,

2. Basin water temperature must be 90°F,

3. Two OPERABLE trains of NSCW tower fans/spray cells, each train with the required number of fans/spray cells, and

4. Two OPERABLE NSCW basin transfer pumps.

2.3 Need for Emergency Change

On June 9, 2024, at 1013 EDT, the 1A NSCW Transfer Pump was removed from service and started for the scheduled quarterly run. After approximately one minute of run time, the pump tripped and TS 3.7.9, Ultimate Heat Sink, Condition D was entered for an inoperable NSCW transfer pump. Intrusive maintenance investigation on June 9 and June 10, 2024, included satisfactory megger of the pump motor and satisfactory hand rotation of the pump. On June 13, 2024, an alternate method of basin transfer was implemented to satisfy Required Action D.1 of TS 3.7.9.

The pump motor was shipped to an off-site vendor for testing and inspection on June 19, 2024.

The motor inspection showed a failure in the windings, which would require a full rewind. On June 20, 2024, the pump was shipped to an offsite vendor for inspection and repairs of damage that was found on the second stage wear ring due to stress corrosion cracking.

E-3 Enclosure to NL-24-0286 Evaluation of Proposed Change

Following installation of the repaired pump and an equivalent motor, testing of the installed pump/motor assembly on July 17, 2024, identified out-of-specification motor current readings.

As a result, the newly installed motor was removed and sent to the vendor for additional testing and inspection.

This emergency amendment is requested to allow for the removal and repair of the 1A NSCW transfer pump motor to perform repairs of the condition that resulted in the out-of-specification motor current condition. With the pump motor off-site for these repairs, TS 3.7.9, Condition F, is set to be entered on July 25, 2024, at 1013 EDT. Additional time is needed because of the complexity of the repair. As of July 19, 2024, the estimated repair timeline is as follows:

x Decouple motor and perform uncoupled run - Complete x Remove electrical connections - Complete x Perform Diving Inspections - Complete x Remove seismic restraints within the cooling tower - Complete x Remove pump from the cooling tower via a roof plug - Complete x Send pump off site for repair - Complete x Install repaired pump in the cooling tower - Complete x Perform Diving Inspections - Complete x Install seismic restraints within the cooling tower - Complete x Repair pump motor - 1004 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.82022e-4 months <br /> x Pump return to site - 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> x Install repaired motor in the cooling tower - 33 hours3.819444e-4 days <br />0.00917 hours <br />5.456349e-5 weeks <br />1.25565e-5 months <br /> x Mount motor to the pump casing - 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> x Install electrical connections - 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> x Perform uncoupled run - 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> x Couple motor to pump and align - 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> x Perform Functional Tests and IST of motor and pump - 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />

From this timeline, the expected time to restore to OPERABLE is approximately 46 days from July 19, 2024. The proposed 92-day CT (which began June 9, 2024) for the NSCW basin transfer pump allows additional time as a contingency for unexpected circumstances. However, SNC will strive to return the pump to OPERABLE status in the minimal time achievable.

2.4 Proposed Technical Specification Change

The proposed change revises TS 3.7.9, Condition D, Required Action D.2 and its associated Completion Time.

A Note is added to the Required Action D.2 Completion Time to provide a one-time extension of the Completion Time (CT) for this Required Action specifically for repairs to the 1A NSCW transfer pump (including its motor). Required Action D.2 requires restoration of an inoperable NSCW basin transfer pump within 46 days. The proposed change would add a Note to Required Action (RA) D.2 which allows a one-time extension of the CT to 92 days for the noted repairs.

E-4 Enclosure to NL-24-0286 Evaluation of Proposed Change

A Note is also added to Required Action D.2 to preclude use of LCO 3.0.4.a and b to return to MODE 4 following 1R25 (which is scheduled to begin on September 9, 2024). Since unlimited operation is allowed in MODE 4 with the pump inoperable, LCO 3.0.4 would allow for a return to operation with the pump inoperable, re-entering Required Action D.2 and allowing for another 46 days for repair. This is not the intended purpose and SNC is adding the Required Action Note to preclude such entry following 1R25 if the repairs have not been completed and the 1A NSCW transfer pump has not been restored to OPERABLE status.

These one-time purpose Notes will expire once TS 3.7.9 Condition D is exited or upon completion of the repairs.

3.0 Engineering Analysis

3.1 Defense-in-Depth

During the time the NSCW transfer pump is out of service, the required fans, basin level, and basin temperature will remain within the limits of the Technical Specifications. Consequently, should an event occur requiring the NSCW system and the UHS, either train will be capable of performing its safety function of providing cooling water, assuming no additional failures. This is inherent in the TS 3.7.9 D.1 ACTION itself, in that a compensatory measure for an alternate method of basin transfer has been provided to satisfy the UHS safety function.

3.2 Safety Margins

The proposed TS change is consistent with the principle that sufficient safety margins are maintained based on the following:

Codes and standards (e.g., American Society of Mechanical Engineers (ASME), Institute of Electrical and Electronic Engineers (IEEE) or alternatives approved for use by the NRC) are met. The proposed change is not in conflict with approved codes and standards relevant to the NSCW system.

The NSCW system and the UHS have sufficient capacity to function for design basis accidents. Assuming no additional failures, the FSAR acceptance criteria for the design events will be met should such an event occur during the time that the 1A NSCW transfer pump is out of service.

3.3 Compensatory Measures

To satisfy the requirements for TS 3.7.9, Required Action D.1, an alternate method of basin transfer has been implemented during repair of the 1A NSCW transfer pump. The alternate method utilizes a B-Train NSCW pump, the NSCW cross-tie fill connection, and a 6-inch hose staged for routing along the ground to the A-Train NSCW tower. This compensatory measure ensures that a 30-day inventory of NSCW water is available during a design basis accident.

A simplified drawing of the NSCW system, which shows the alternate method of basin transfer, is provided at the end of this enclosure.

E-5 Enclosure to NL-24-0286 Evaluation of Proposed Change

The alternative means for 1A NSCW water transfer consist of routing a fire hose from the 1B NSCW Tower to the 1A NSCW Tower. The fire hose is connected to the 1B NSCW cross-pumping flange and will be routed to the 1A NSCW Tower.

The detailed actions for the alternative transfer source are governed by an NSCW System operating procedure, which instructs maintenance personnel to implement the alternative source transfer in the field and give Operators clear instructional guidance in the event of an occurrence when the transfer system is called upon to perform its function. In addition, standing orders will be issued in the control room to promote awareness and to ensure expectations and guidance is understood by all oncoming shift operators.

In support of the plants readiness for implementing the alternative means for NSCW transfer, the fire hose will initially be connected to the flange for cross-pumping. In the case of an event, doors will be propped open and the fire hose routed to the 1A tower in support of NSCW transfer.

No additional maintenance or operating training is required. The actions that will be performed in support of the alternative source for transfer are already governed by system operating procedure and are supported by system operating training and initial maintenance training. The actions involved for implementing the alternative transfer source is connecting a fire hose to NSCW piping and valve manipulation to allow water flow to the 1A NSCW Tower.

3.4 Maintenance Rule Control

Since this is a one-time change, it is not expected that additional out-of-service time for the 1A NSCW transfer pump will adversely affect the performance of this pump or the NSCW system.

The NSCW transfer pumps are included under the VEGP Maintenance Rule Program and function to transfer NSCW water between cooling water basins. The pumps' function is to operate during a design basis accident (DBA) and the pumps are on standby during normal operation. The pumps reliability is tracked by quarterly IST testing. If adverse conditions exist, then IST testing is increased to monthly testing until the problem is identified and resolved. If the pre-established reliability performance criteria for the NSCW transfer pumps are exceeded, the pumps are evaluated for the 10 CFR 50.65(a)(1) actions, which requires increased management attention and goal setting in order to restore their performance to an acceptable level.

3.5 Risk

This license amendment has been reviewed with respect to risk for Vogtle Unit 1. There would be no increase to the core damage frequency (CDF) or large early release frequency (LERF) in the plant-specific probabilistic risk assessment (PRA) as a result of this license amendment.

The Nuclear Service Cooling Water (NSCW) and the Ultimate Heat Sink (UHS) systems are modeled in the PRA; However, the NSCW transfer pumps are not explicitly or implicitly modeled.

NSCW cooling tower basin transfer is only needed in the event of a Design Basis Accident (DBA) requiring long-term cooling, up to the design basis mission time of 30 days. The specific time at which makeup from the standby train to the in-service train would occur varies due to

E-6 Enclosure to NL-24-0286 Evaluation of Proposed Change

heat loads and ambient conditions, however, this time would be much greater than the 24-hour mission time of the PRA.

Additionally, there is a low risk of losing a NSCW train when the 1A NSCW transfer pump is inoperable for the following reasons:

x TS 3.7.9, Required Action D.1, requires compensatory measures for alternate basin transfer to be implemented within 8 days. This action was completed on June 13, 2024.

x Additional defense-in-depth strategies using FLEX are available should the primary alternate basin transfer compensatory method fail. Methods to makeup the UHS basins during a DBA (from the test well or from the circulating water basin) are discussed in FLEX procedure NMP-OS-019-002-GL03.

Repair Capabilities: NSCW transfer is only needed in the event of a Design Basis Accident.

Any needed repairs would be completed expeditiously. Additionally, the electrical power to the Operable NSCW train is protected per plant procedures for the duration of the extension and work is limited to further ensure the reliability of the opposite train power.

Supplemental Equipment: If supplemental equipment were needed to transfer water from basin to basin an already identified pump (hydraulically driven submersible pump) with sufficient pump head and comparable flow is available onsite. This pump would be able to pump water from the bottom of either basin to the desired basin utilizing a separate already identified mechanical power source (diesel - hydraulic power skid). The use of supplemental equipment is described in the operational guidance in the NSCW System operating procedure. This represents a defense-in-depth strategy which does not rely on like power sources to facilitate basin transfer.

4.0 Regulatory Analysis

4.1 Applicable Regulatory Requirements The design of the NSCW system and the Ultimate Heat Sink satisfies the criteria of 10 CFR 50.36, Technical Specifications, paragraph (c)(2)(ii), Criterion 3, which states the following:

(ii) A technical specification limiting condition for operation of a nuclear reactor must be established for each item meeting one or more of the following criteria:

Criterion 3. A structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.

The NSCW system and the Ultimate Heat Sink are described in the VEGP FSAR Sections 9.2.1 and 9.2.5.

The design of the NSCW System and the Ultimate Heat Sink satisfies the requirements of 10 CFR 50, Appendix A, General Design Criteria 44 which states, in part:

E-7 Enclosure to NL-24-0286 Evaluation of Proposed Change

Criterion 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.

4.2 Precedent

On October 31, 2016, the NRC issued a similar amendment for Southern Nuclear Operating Company (SNC) regarding Vogtle Electric Generating Plant, Unit 2 [ADAMS Accession No. ML16265A162] to allow for refurbishing the 2B NSCW transfer pump. This change extended the restore action from 31 days to 46 days on a one-time basis.

On September 19, 2017, the NRC issued a second amendment for Southern Nuclear Operating Company (SNC) regarding Vogtle Electric Generating Plant, Unit 2 [ADAMS Accession No. ML17213A1 3] that permanently extended the restore action from 31 days to 46 days and included a new Condition and Actions for two NSCW pumps inoperable.

4.3 No Significant Hazards Evaluation

Pursuant to 10 CFR 50.90, Southern Nuclear Operating Company hereby requests an emergency amendment to Vogtle Electric Generating Plant (VEGP) Unit 2 Operating License NPF-81. The proposed change would revise Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.7.9, Ultimate Heat Sink (UHS), such that a 92-day Completion Time is allowed for Required Action D.2 for an inoperable nuclear service cooling water (NSCW) basin transfer pump. The TS changes would be a one-time change and in effect only during Vogtle Unit 1 Cycle 25.

Southern Nuclear Operating Company (SNC) has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, Issuance of Amendment, as discussed below:

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No

The proposed change does not alter any plant equipment or operating practices in such a manner that the probability of an accident is increased. The proposed changes will not alter assumptions relative to the mitigation of an accident or transient event. Furthermore, the ultimate heat sink (UHS) will remain capable of adequately responding to a design basis event during the period of the extended completion time (CT). Therefore, the proposed

E-8 Enclosure to NL-24-0286 Evaluation of Proposed Change

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

2. Does the proposed change create the possibility of a new or different accident from any accident previously evaluated?

Response: No

The proposed change does not introduce any new or unanalyzed modes of operation. The repair of the pump does not involve any unanalyzed modifications to the design or operational limits of the nuclear service cooling water (NSCW) system. The redundant pump and compensatory measures allowed by the Technical Specifications will remain unaffected.

Therefore, no new failure modes or accident precursors are created due to the pump repair during the extended Completion Time. For the reasons noted above, the proposed change will not create the possibility of a new or different accident previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No.

The margin of safety is related to the ability of the fission product barriers to perform their design functions during and following an accident. These barriers include the fuel cladding, the reactor coolant system, and the containment. The performance of these fission product barriers will not be affected by the proposed change; therefore, the margin to the onsite and offsite radiological dose limits are not significantly reduced.

During the extended CT for the NSCW transfer pump, the NSCW system and the UHS will remain capable of mitigating the consequences of a design basis event such as a loss of coolant accident (LOCA). Technical Specifications 3.7.9 Action D.1 will be taken to provide an alternate method of basin transfer.

For the reasons noted above, there is no significant reduction in a margin of safety.

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 Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 Environmental Assessment

SNC has evaluated the proposed amendment and has determined that the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released off site, or (iii) a significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the proposed amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact

E-9 Enclosure to NL-24-0286 Evaluation of Proposed Change

statement or environmental assessment need to be prepared in connection with the proposed amendment.

E-10 Enclosure to NL-24-0286 Evaluation of Proposed Change

SIMPLIFIED NSCW DRAWING OF ALTERNATE TRANSFER CONFIGURATION

E-11 AT T ACHMENT 1 to NL 0286 T echnical Specification M ar ked-up Pages

Emer gency R equest to R evise T echnical Specification 3.7.9 for a O ne-T ime C hange to Support a Unit 1 Nuclear Service Cooling Water T ransfer Pump Repair

(This Enc losure inc ludes 2 pages, inc luding this c ov er page.)

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AT T ACHMENT 2 to NL-24-0286 R evised T echnical Specifications Pages

Emer gency R equest to R evise T echnical Specification 3.7.9 for a O ne-T ime C hange to Support a Unit 1 Nuclear Service Cooling Water T ransfer Pump Repair

(This Enc losure inc ludes 2 pages, inc luding this c ov er page.)

UHS 3.7.9

ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME

D. One NSCW basin D.1 Implement an alternate 8 days transfer pump method of basin transfer inoperable. to the affected basin.

AND

D.2 ------------NOTE---------- ------------NOTE----------

LCO 3.0.4.a and b are A one-time only not applicable for initial change of the entry into MODE 4 Completion Time to following 1R25 until 92 days is permitted completion of 1A NSCW for the 1A NSCW transfer pump repair. transfer pump repair

---

during Vogtle Unit 1, Cycle 25. The Restore the transfer increased Completion pump to OPERABLE Time is applicable only status. to the 1A NSCW transfer pump.

46 days

E. Two NSCW basin E.1 Implement an alternate 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> transfer pumps method of basin transfer inoperable. for one NSCW basin transfer pump.

AND

E.2 Restore one NSCW 8 days basin transfer pump to OPERABLE status.

F. Required Action andF.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion Time not met. AND

OR F.2 -------------NOTE------------

LCO 3.0.4.a is not UHS inoperable for applicable when entering reasons other than MODE 4.

Conditions A, B, C, D, or ---------------------------------

E.

Be in MODE 4. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />

Vogtle Units 1 and 2 3.7.9-2 Amendment No. ___ (Unit 1)

Amendment No. 175 (Unit 2)

AT T ACHMENT 3 to NL-24-0286 T echnical Specifications B ases M ar ked-up Pages (for information only)

Emer gency R equest to R evise T echnical Specification 3.7.9 for a O ne-T ime C hange to Support a Unit 1 Nuclear Service Cooling Water T ransfer Pump Repair

(This Enc losure inc ludes 3 pages, inc luding this c ov er page.)

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