NL-16-1246, Request to Revise Technical Specifications LCO 3.7.9 for a One-Time Change to Support a Unit 2 Nuclear Service Cooling Water Transfer Pump Refurbishment

Request to Revise Technical Specifications LCO 3.7.9 for a One-Time Change to Support a Unit 2 Nuclear Service Cooling Water Transfer Pump Refurbishment

ML16225A619
Person / Time
Site:	Vogtle
Issue date:	08/12/2016
From:	Wheat J Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-16-1246
Download: ML16225A619 (13)

Text

• Justin T. Wheat Southern Nuclear Nuclear Licensing Manager Operating Company, Inc.

40 Inverness Center Parkway Post Office Box 1295 Birmingham, AL 35242 Tel 205.992.5998 SOUTHERN << \

Fax 205.992.7601 NUCLEAR A SOUTHERN COMPANY August12,2016 Docket No.: 50-425 NL-16-1246 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant- Unit 2 Request to Revise Technical Specifications LCO 3.7.9 for a One-Time Change to Support a Unit 2 Nuclear Service Cooling Water Transfer Pump Refurbishment Ladies and Gentlemen:

Pursuant to 10 CFR 50.90, Southern Nuclear Operating Company hereby requests an 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 with the 28 Nuclear Service Cooling Water (NSCW) transfer pump inoperable for refurbishment, the Completion Time of Condition 3.7.9.D.2.2 would be 46 days as opposed to 31 days. This TS change would be a one-time change and in effect only for the 28 NSCW transfer pump for the remainder of Cycle 19.

The proposed amendment is needed because the 28 NSCW transfer pump must be refurbished. It is desirable to refurbish the pump during normal operation because, while the pump is fully operable, it is exhibiting a decline in performance. The removal of the 28 NSCW transfer pump is scheduled to begin the week of October 3, 2016.

SNC requests approval of the proposed license amendment by October 1, 2016. The proposed change would be effective immediately upon issuance of the amendment.

Enclosure 1 contains a description of the proposed change, the supporting engineering analysis and the no significant hazards determination. Enclosure 2 contains the marked-up TS page, and Enclosure 3 provides the clean-typed TS page. No changes are proposed to the TS Bases.

This letter contains no NRC commitments.

If you have any questions, please contact Ken McElroy at (205) 992-7369.

U.S. Nuclear Regulatory Commission NL-16-1246 Page2 Mr. J. T. Wheat states he is Nuclear Licensing Manager of Southern Nuclear Operating Company, is authorized to execute this oath on behalf of Southern Nuclear Operating Company and, to the best of his knowledge and belief, the facts set forth in this letter are true.

Respectfully submitted,

~c~

J.~at.

Nuclear Licensing Manager .

~

)

?

JTW/kgl/lc to and subsc1'jd before me this J2}!day of A~ '2016.

~ C;i?~J--

Notary Public My commission expires: /6 - 8 *)1J l1

Enclosures:

1. Description and Assessment of Proposed Change

2. Marked-Up Technical Specifications Page

3. Clean-Typed Technical Specifications Page cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Bost, Executive Vice President & Chief Nuclear Officer Mr. D. R. Madison, Vice President- Fleet Operations Mr. M. D. Meier, Vice President- Regulatory Affairs Mr. B. K. Taber, Vice President- Vogtle 1 & 2 Mr. B. J. Adams, Vice President- Engineering Mr. G. W. Gunn, Regulatory Affairs Manager- Vogtle 1 & 2 RType: CVC7000 U. S. Nuclear Regulatory Commission Ms. C. Haney, Regional Administrator Mr. R. E. Martin, NRR Senior Project Manager- Vogtle 1 & 2 Ms. N. R. Childs, Senior Resident Inspector- Vogtle 1 & 2 State of Georgia Mr. J. H. Turner, Director- Environmental Protection Division

Vogtle Electric Generating Plant- Unit 2 Request to Revise Technical Specifications LCO 3.7.9 for a One-Time Change to Support a Unit 2 Nuclear Service Cooling Water Transfer Pump Refurbishment Enclosure 1 Description and Assessment of Proposed Change Description and Assessment of Change Enclosure 1 Description and Assessment of Change 1.0 Description Pursuant to 10 CFR 50.90, Southern Nuclear Operating Company hereby requests an 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 with the 2B Nuclear Service Cooling Water (NSCW) transfer pump inoperable for refurbishment, the Completion Time of Condition 3.7.9.D.2.2 would be 46 days as opposed to 31 days. This TS change would be in effect only for the 2B NSCW transfer pump for the remainder of Cycle 19. This LCO requires that the NSCW transfer pump be OPERABLE in Modes 1, 2, 3, or 4.

The proposed amendment is needed because the 2B NSCW transfer pump must be refurbished. It is desirable to refurbish the pump during normal operation because, while the pump is fully operable, it is exhibiting a decline in performance.

Condition 3.7.9.D requires that, if the required NSCW basin transfer pump is inoperable, then the inoperable pump must be restored to OPERABLE status within 8 days OR an alternate method of basin transfer must be implemented within 8 days AND the inoperable pump must be restored to OPERABLE status within 31 days. If these ACTIONS and the associated Completion Times are not met, the reactor must be taken to Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> AND to Mode 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The proposed amendment revises the Completion Time for ACTION 3.7.9.D.2.2 from 31 days to 46 days, but will apply only to the 2B Nuclear Service Cooling Water (NSCW) transfer pump.

Furthermore, this change will only be used one time on VEGP Unit 2 prior to the Cycle 19 shutdown for the purpose of refurbishing the 2B NSCW transfer pump.

2.0 Background

2.1 Need for Amendment This amendment is needed to allow for the refurbishment of the 2B Nuclear Service Cooling Water (NSCW) transfer pump. It is necessary to perform the pump refurbishment due to degraded performance. Additional time is needed because of the complexity of the refurbishment which includes: decoupling the motor, removal of electrical and cooling water connections, removal of physical interferences within the cooling tower, removal of the pump from the cooling tower via a roof plug, sending the pump off site for refurbishment, installing the refurbished pump in the cooling tower, mounting the motor to the pump casing, making all the electrical and cooling water connections, running the motor uncoupled, coupling the motor to the pump, alignment, and finally performing a coupled run of the motor and pump.

Discovery from a previous NSCW transfer pump (1 B) refurbishment in 2008 indicated the Chromalloy coating on the wear rings was flaking off. The coating loss resulted in larger clearances and worsening the low pump delta pressure values during 1ST testing. The 2B NSCW transfer pump has been in its alert range due to low delta pressure since 2011. As a result, VEGP has increased the frequency of their In-Service Testing (1ST) from quarterly to monthly surveillances. Furthermore, Operations has been burdened with frequently testing the El-l Description and Assessment of Change pump. The pump's degrading performance is leaving VEGP with reduced margin for the future.

Refurbishment will restore pump margin, improve operation, and increase equipment reliability.

The NSCW transfer pump is a column type design which is over 80 feet in length. There are 7 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 7 pairs of seismic pins are roughly but not exactly 180 degrees apart on their respective flanges. When the pumps were installed 30 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 total 31 day schedule duration for the NSCW transfer pump refurbishment includes approximately 4 days for removal, 21 days for refurbishment, and 6 days for reinstallation.

Efforts have been made to reduce schedule duration. The vendor has committed to refurbish the pump in 21 days. VEGP has preordered raw materials for the vendor to have available during refurbishment, and the vendor will send some of the sections of the pump early while refurbishment is still in progress. The work is estimated to take all31 days of the Completion Time for LCO Condition 3.7.9., Required Action 0 .2.2. The 15 day increase in Completion Time is requested to cover uncertainties in the refurbishment schedule.

2.2 System Description

The Nuclear Service Cooling Water (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 Ultimate Heat Sink (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.

The UHS provides a heat sink for processing 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 Component Cooling Water (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 El-2 Description and Assessment of Change water supply assuming the worst combination of meteorological conditions and accident heat loads which maximize the tower heat load, basin temperature, and evaporative losses. This NSCW transfer pump needs to be refurbished because of degraded performance.

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 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 s 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.

3.0 Engineering Analysis 3.1 Defense-in-Depth During the time the 2B 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 3.7.9.D.2 ACTION itself, in that a compensatory measure for an alternate method of basin transfer is required; if such method is not available, the 31 day Completion Time (CT) cannot be used. In such a situation, an 8 day CT would be in effect per ACTION 3.7.9.D.1. If the 8 day CT could not be met, the unit is taken to Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> AND to Mode 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. In this proposed amendment, the 3.7.9.D.2.2 CT would be extended (for the 2B NSCW transfer pump only) for a period of up to 46 days.

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 2B NSCW transfer pump is out of service.

El-3 Description and Assessment of Change 3.3 Compensatory Measures To satisfy the requirements for Action 3.7.9.0.2.1, an alternate method of basin transfer will be implemented during refurbishment of the 28 NSCW transfer pump. The alternate method will utilize an A-Train NSCW pump, the NSCW cross-tie fill connection, and a 6 inch hose staged for routing along the ground to the S-Train NSCW tower. This compensatory measure will ensure that a 30 day inventory of NSCW water is available during a design basis accident.

3.4 Maintenance Rule Control Since this is a one-time change, it is not expected that additional out-of-service time for the 28 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. Since the pumps' function is to operate during design basis accident (DBA) and the pumps are on standby the majority of the time, Maintenance Rule unavailability hours are exempt. The pumps' reliability is tracked by quarterly 1ST testing. If adverse conditions exist then 1ST 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 The risk will be low when the 28 NSCW transfer pump is INOPERABLE during refurbishment because Action 3.7.9.0.2.1 for the compensatory measures will be in place. Shutting down the reactor to refurbish the pump with the subsequent start-up would introduce unnecessary transition risk. The VEGP NSCW system and the Ultimate Heat Sink are modeled in the Probabilistic Risk Assessment (PRA model). However, the NSCW transfer pumps are not included in the PRA model. This license amendment has been reviewed with respect to risk for VEGP. There is no impact on the core damage frequency (CDF) or large early release frequency (LERF) as modeled in the PRA for VEGP as a result of this license amendment.

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.

El-4 Description and Assessment of Change 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:

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 No Significant Hazards Evaluation This amendment request proposes a one-time change to the Unit 2 Vogtle Electric Generating Plant (VEGP} Technical Specifications Limiting Condition for Operation (LCO} 3.7.9. The one-time change would revise the Completion Time (CT} for ACTION 3.7.9.D.2.2 from 31 days to 46 days. However, the 46 day CT would only be applicable for a one-time refurbishment of the 28 Nuclear Service Cooling Water transfer pump. Furthermore, the revised CT would apply only until the end of the Unit 2 VEGP current operating cycle 19. At the start of cycle 20, the CT for ACTION 3.7.9.D.2.2 would revert to 31 days for all NSCW transfer pumps.

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 UHS will remain capable of adequately responding to a design basis event during the period of the extended CT. Therefore, the proposed 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 El-5 Description and Assessment of Change The proposed change does not introduce any new or unanalyzed modes of operation. The refurbishment of the pump does not involve any unanalyzed modifications to the design or operational limits of the 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 refurbishment 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 Completion Time for the 28 NSCW transfer pump, the NSCW system and the UHS will remain capable of mitigating the consequences of a design basis event such as a LOCA. Technical Specifications Action 3.7.9.D.2.1 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.

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

El-6

Vogtle Electric Generating Plant- Unit 2 Request to Revise Technical Specifications LCO 3.7.9 for a One-Time Change to Support a Unit 2 Nuclear Service Cooling Water Transfer Pump Refurbishment Enclosure 2 Marked-Up Technical Specification Page

UHS 3.7.9 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME D. One NSCW basin D.1 Restore the transfer 8 days transfer pump pump to OPERABLE inoperable. status.

OR D.2.1 Implement an alternate 8 days method of basin transfer.

AND D.2.2 Restore the transfer pump to OPERABLE 31 days\

status.

E. Required Action and E.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 E.2 -------------NOTE------------

LCO 3.0.4.a is not UHS inoperable for applicable when entering reasons other than MODE4.

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

Be in MODE 4. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> NOTE A one-time only change of the

\

Completion Time to 46 days is permitted for the 2B NSCW transfer pump refurbishment during

- Vogtle Unit 2, Cycle 19. The increased Completion Time is applicable only to the 2B NSCW transfer pump.

Vogtle Units 1 and 2 3.7.9-2 Amendment No. 179 (Unit 1)

Amendment No. 160 (Unit 2)

Vogtle Electric Generating Plant - Unit 2 Request to Revise Technical Specifications LCO 3.7.9 for a One-Time Change to Support a Unit 2 Nuclear Service Cooling Water Transfer Pump Refurbishment Enclosure 3 Clean-Typed Technical Specification Page

UHS 3.7.9 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME D. One NSCW basin D.1 Restore the transfer 8 days transfer pump pump to OPERABLE inoperable. status.

OR D.2.1 Implement an alternate 8 days method of basin transfer.

AND D.2.2 Restore the transfer ------------NOTE----------

pump to OPERABLE A one-time only status. change of the Completion Time to 46 days is permitted for the 2B NSCW transfer pump refurbishment during Vogtle Unit 2, Cycle 19. The increased Completion Time is applicable only to the 2B NSCW transfer pump.

31 days E. Required Action and E.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 E.2 -------------NOTE------------

LCO 3.0.4.a is not UHS inoperable for applicable when entering reasons other than MODE4.

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

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. (Unit 2)