ML13336A545

11/13/13 Presentation Slides from Meeting with Duke Energy Carolinas, LLC, Oconee Nuclear Station Units 1, 2, and 3, Keowee Hydro Unit Generator Field Pole Rewind Project - License Amendment Request

ML13336A545
Person / Time
Site:	Oconee
Issue date:	11/13/2013
From:	Shingleton B Duke Energy Carolinas
To:	Office of Nuclear Reactor Regulation
Guzman R V
References
Download: ML13336A545 (29)

Text

Oconee Nuclear Station Improving Keowee Reliability, November 13, 2013

Duke Participants Scott Batson, Site Vice President, Oconee Nuclear Station Ed Burchfield, Engineering Manager, Oconee Nuclear Station Todd Grant, Critical Systems Engineering Manager, Oconee Nuclear Station Terry Patterson, Safety Assurance Manager, Oconee Nuclear Station Chris Nolan, Director Regulatory Affairs, Duke Energy For Information Only 2

Agenda Opening Remarks Scott Batson Improving Keowee Reliability

- Generator Pole Rewind Project Ed Burchfield Required Technical Specification Change Todd Grant Outage Duration Timeline Todd Grant Diverse Backup Power for Emergency Power System Todd Grant Critical Activity Plan

- Risk Reduction Measures Todd Grant Closing Comments Scott Batson For Information Only 3

Opening Remarks Scott Batson Site Vice President, Oconee Nuclear Station For Information Only 4

Improving Keowee Reliability

- Generator Pole Rewind Project Ed Burchfield Engineering Manager, Oconee Nuclear Station 5 For Information Only

Improving Keowee Reliability

- Generator Field Pole Rewind Project Keowee Hydro Station commissioned in 1971 Previous Major Maintenance and Refurbishment Upgrades 1979 - weld repair of turbine blades for each KHU 1987 - Keowee Hydro Unit (KHU)

-1 generator stator maintenance 1994 - Keowee transformer upgrade 2004 and 2005 for each KHU

- Turbine refurbishment; governor, voltage regulator, and battery replacements 2008 - 2009 preventative maintenance inspections identified aging mechanisms in rotor pole assemblies 2009 Duke Energy started planning efforts to refurbish/overhaul both Keowee generators First phase is to refurbish/replace all 56 generator field poles on each KHU KHU-2 scheduled for January 2014 KHU-1 scheduled for July 2014 Second phase is to refurbish stator for each KHU planned for 2016 and 2017 6 For Information Only

Generator Pole Rewind Project 7 For Information Only

Generator Pole Rewind Project Todd Grant Critical Systems Engineering Manager Oconee Nuclear Station 8 For Information Only

Technical Specification Change Needed to Allow Work to Proceed LAR 2012-01 requests a separate one time 75 day Technical Specification (TS) completion time for each KHU when aligned to the overhead path for pole rewind work TS 3.8.1 C

- KHU aligned to the overhead path out of service (OOS)

Cumulative 45 day completion time over a 3 year period.

TS 3.8.1 H

- Planned Dual KHU OOS*

60 hour6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> completion time for planned work Cumulative 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> limit over a 3 year period when using the 45 day completion time A portion of the 45 day completion time has been used for each KHU for Protected Service Water (PSW) tie

-in work: 30 days available for KHU

-1 22 days available for KHU

-2 No cumulative dual unit completion time has been used in the last 3 years.

The License Amendment Request (LAR) is requesting additional OOS time for a KHU when aligned to the overhead path

• Risk Mitigation Plans will preclude entering dual unit outage if severe weather is forecast in the area.

9 For Information Only

Keowee Generator Pole Rewind Outage Timeline 10 For Information Only Risk Reduction Single KHU outage duration reduced from 75 days to 62 days Dual KHU outage duration reduced from 160 hours0.00185 days <br />0.0444 hours <br />2.645503e-4 weeks <br />6.088e-5 months <br /> to 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> Start Finish Revised 62 Days - Total Work Window 1.7 days - Dewater Dual KHU Outage 2.1 days - Dewater Dual KHU Outage 35 days physical work 4 days balancing 4 days testing 10 days contingency for physical work 5.6 days outage contingency 35 days physical work Finish 15 days contingency f or physical work 7.7 days outage contingency problems Original 75 Days - Total Work Window 1 day balance run s .83 day balance shot s (dual KHU outage)

Final balance run (2 days) 4.7 days testing .83 day contingency balance shots (dual KHU outage) 1 day contingency balance run s 1.7 days - Dewater Dual KHU Outage 1.7 days - Dewater Dual KHU Outage 1.7 days - Dewater Dual KHU Outage Note: Risk Mitigation Plans will preclude entering dual unit outage if severe weather is forecast in the area

ONS Electrical Distribution System 11 For Information Only 2 1 4 3 4 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 27 28 31 33 54 55 56 57 58 59 60 61 4 T KEOWEE HYDRO Gen 2 Gen 1 40 AUXILIARY POWER SYSTEM to B 4 T 1 T CT 1 6900 Main Generator Unit #1 6900 4160 NORMAL SOURCE STARTUP SOURCE 2 TA 2 TB 2 T CT 2 6900 4160 Main Generator Unit #2 6900 4160 NORMAL SOURCE STARTUP SOURCE 3 TA 3 TB 3 TC 3 TD 3 TE 3 T CT 3 6900 Main Generator Unit #3 6900 4160 NORMAL SOURCE STARTUP SOURCE N 1 N 2 E 1 E 2 S 1 S 2 AUXILIARY POWER SYSTEM to B 3 T MFB #1 MFB #2 MFB #1 MFB #2 CT 4 4160 CS 90 CT 5 4160 22.6 Miles Central White SK 1 SK 2 SL 1 SL 2 AUTO TRANSFORMER 5 T STANDBY BUS

1. 1 STANDBY BUS

1. 2 KEOWEE OVERHEAD KATOMA ASBURY NEWPORT SOUTH HALL 525 KV RED BUS YELLOW BUS RED BUS YELLOW BUS 230 KV (NORTH GREENVILLE

)DACUS (CENTRAL)OCONEE (CENTRAL)CALHOUN JOCASSEE 13.8 KV UNDERGROUND FEEDER 4160 EMERGENCY STARTUP BUS 6900 STARTUP BUS NORMAL ALTERNATE B 3 T B 4 T NORMAL FROM 4 T FROM 5 T AUXILIARY POWER SYSTEM ELECTRICAL DISTRIBUTION B W W B W B W B Aux Transformer Aux Transformer Aux Transformer Main Transformer Main Transformer Main Transformer Startup Transformer Startup Transformer Startup Transformer 1 TC 1 TD 1 TE N 1 N 2 E 1 E 2 S 1 S 2 2 TC 2 TD 2 TE N 1 N 2 E 1 E 2 S 1 S 2 MFB #1 MFB #2 Unit 1 HPIP Unit 3 HPIP Unit 2 HPIP ASWP UNIT 1 & 3 PRIMING PUMP A H P S W P B H P S W P SSF OTS 1 4160/600 AUXILIARY SERVICE SWITCHGEAR Disconnect open Disconnect closed 30 1 TA 1 TB 1 A 1 RCP 1 B 1 RCP 1 A 2 RCP 1 B 2 RCP 2 A 1 RCP 2 B 1 RCP 2 A 2 RCP 2 B 2 RCP 3 A 1 RCP 3 B 2 RCP 3 A 2 RCP 3 B 1 RCP OCB 41 OCB 101 Central Switchyard 100 KV 1 11 7 C CT 8 C CT 2 12 34 13 Lee Switchyard 100 KV 8.5 Miles Fant Black OCB 35 SL 1/2 Trip Interlock Defeat switch In Central

always has degraded grid protection Auto/Man In Auto: always has UV protection SL 1&2 are manual brkrs (no auto closure

)Close on SYI with ES or MFBMP timed out SBCI: Must have Load Shed

Prevents closing 'E' brkrs Allows closing 'S' brkrs SYI:- Starts Keowee units

- Isolates Yellow bus

- Feeds S/U Xfmrs via overhead path (ACB 1 or 2 and 18 , 27 , 30 close)- Opens RCP brkrs from S

/U Xfmr (Aux still feeds

) SYI Complete

All required brkrs open Allows PCB 9 to close Allows ACB 1 & 2 to close SYI:- UV or UF on same 2/3 Yellow and Red buses OR - Yellow bus

<227.468 Kv for > 9 sec and ES 1 or 2 230 KV bus L.O. overrides SYI

.Opens on SYI. Recloses after 8.5 sec.Aux Xfmr is sized for its own unit loads plus 2 nd unit ES loads SYI causes 1 sec delay in closing 'E' brkrs to prevent closing out of phase. SWYD Xfmrs and L

.C.s are pwrd from 1 TE & 2 TE.Red / Yellow Bus Differential L

.O.230- must be manually reset

.525- Auto resets when PCBs open

.LCT - can be started w/I 1 hr.TCC operates brkrs.Transfer switch must be in manual to close SL 1 & 2 brkrs. CT 4/5 rated for ES loads from 1 unit plus Load Shed loads from other 2 units. Loss if pwr to 4 T/5 T will cause auto swap of B 3 T/B 4 T to alt pwr supply PIAC C & D Chillers ACB 1 or 2 close 11 sec after SYI complete X 5 & X 6 Load Shed if all the following:- Load shed signal (SBCI)- SL Brkrs closed

- No ES Automatically come back after 30 seconds.1 X 7 , 2 X 4 & 3 X 4 Always Load Shed and come back after 60 sec (even if pwr not restored yet

)Limits & Precautions

Cross-connection between transformers (1 , 2 , 3)T and CT-(1 , 2 , 3) through the 4160 V buses should be limited to the time required to perform a normal transfer of auxiliary loads

.Extended cross

-connection could backcharge the transformer with the lower output voltage and create an overcurrent condition with the buses and/or associated breakers

.LOCA Load Shed occurs on ES and CRD Trip Confirm

.Purpose: to reduce post LOCA Rx trip voltage dip by tripping 4 kv , nonsafety related , secondary system pump motors in the event of LOCA or inside cntmt MSLB with offsite pwr. Resets automatically after 10 seconds. If Auto/Man switch left in the Man position , 'E' brkr still auto swaps on unit trip. If Auto/Man switch left in the mid postion , prevents 'E' brkr from auto swapping on unit trip.PCB 21 , 24 , 58 & 59 must be closed before the auto

/man switch is placed in auto to arm the rapid bus Xfer. If not , a slow bus Xfer will occur (i.e. lose secondary but RCPs stay on) unless the switch is cycled to man and back to auto. ELECTRICAL Distribution DRAWING #DATE: 9/21/10 TRAINING USE ONLY

REFERENCE:

DRAWN BY: SRS APPROVED BY

OP-OC-EL-EPD-2 rev 2 700 series O Drawings Signature On File SL 1 & SL 2 TRIP INTERLOCK DEFEAT CH 1 CT 5 BUS 1 AUTO / MAN CENTRAL LEE AUTO MAN MFB 2 AUTO/MAN ONS Transmission Lines 12 For Information Only Oconee Nuclear Station Oconee Nuclear Station Defense-in-Depth - Multiple Diverse Backup Power Sources 13 For Information Only Start Finish Keowee Outage Timeline 6 2 Days - Total Work Window 1.7 days - Dewater Dual KHU Outage 4 days balancing 4 days testing Temporary Diesel Generator at Keowee for restoring KHU associated U/G Path PSW Power System installed for use to SSF SSF Operable (including SSF DG) 1 Lee CT running and energizing Standby Bus es 2 nd Lee CT in Standby available within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 9 offsite power sources available Two Jocassee Hydro Unit s available within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 10 days contingency for physical work 5.6 days outage contingency 35 days physical work Temporary diesel-driven feedwater pump (Hale Pump) 1.7 days - Dewater Dual KHU Outage Underground (U/G) KHU existing additional

Additional Power Sources Considered Additional onsite temporary power sources beyond those already mentioned were considered but none provided significant risk benefit Overall Incremental Conditional Core Damage Probability (ICCDP) for extended outage is 5E-08 Additional onsite diesel generators (DGs) have negligible risk benefit of < 1E

-08 ICCDP Additional Temporary DGs considered Temporary DGs to power safe shutdown loads Temporary DGs to power the Standby Shutdown Facility (SSF)

Temporary DGs to power station Auxiliary Service Water (ASW) loads Challenges Station LOOP load approximately 10,000 KW requiring a minimum 6 package DGs DG and fuel tanker staging, environmental and fire concern issues 3 Unit Load sequencing issues Complex operating procedures and coordination between Control Rooms First of a kind application that would result in deferring January Keowee outage and significantly challenging the July Keowee outage 14 For Information Only

Backup Power for Emergency Power System LAR 2012-01 currently credits following backup power sources Underground Keowee Hydro Unit Dedicated Lee Combustion Turbine energizing both Standby Buses during extended completion time Remaining LCT available and capable of energizing the Standby Buses within one hour Required offsite power sources available SSF capable of mitigating SBO for at least 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Additional backup power sources Two dedicated Jocassee Hydro Units available either of which has capacity of powering ONS shutdown loads within approximately one hour Temporary diesel generator at Keowee capable of restoring unwatered Underground KHU within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Temporary diesel

-driven feedwater pump (Hale pump) to feed steam generators PSW power system installed and capable of powering SSF 15 For Information Only

Alternate Methods of Maintaining Safe Shutdown The following systems/equipment can be used to maintain all three Oconee units in a safe shutdown condition:

Turbine Driven Emergency Feedwater Pump capable of feeding steam generators SSF operable and capable of providing alternate shutdown capability Onsite diesel

-driven Hale feedwater pump capable of feeding steam generators One or more of the following power sources can be used to place all three Oconee units in cold shutdown: One LCT energizing ONS standby buses prior to outage start Underground KHU A second LCT can be started and aligned to the standby buses within one hour Two Jocassee Hydro Units available either of which can be aligned to the Oconee 230kV Yellow Bus within approximately one hour Any of multiple offsite power sources 16 For Information Only

Lee Combustion Turbines Two LCTs (7C, 8C) available to power Oconee standby buses Dedicated line electrically separated from the system grid and offsite loads Capacity to supply ONS shutdown loads Routinely operate/test demonstrating reliability Black start capable, tested annually Included in the ONS Normal and Emergency Operating Procedures Verified available each shift Manned continuously 17 For Information Only

Lee Combustion Turbines 18 For Information Only

Jocassee Hydro Station Two of the four Jocassee Hydro Units can be separated from the grid and dedicated to ONS within approximately one hour Each Jocassee Hydro Station unit is rated at 195 MW Two transmission lines, north of ONS, directly connect the Jocassee 230 kV switchyard to the Oconee 230 kV switchyard Capacity to supply ONS shutdown loads Routinely operate/test demonstrating reliability Black start capable, tested annually Included in the ONS Emergency Operating Procedures Verified available each shift Manned continuously 19 For Information Only

Jocassee Hydro Station 20 For Information Only

Temporary DG located at Keowee for restoring U/G KHU Onsite DG supplies backup power to KHS during dual KHU outage when unwatered Adequate capacity to restore the underground KHU Allows for rapid restoration of the underground KHU during loss of all power (4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) Black start capable Use approved Keowee operating procedures Operated and tested prior to outage Verified available each shift Keowee Hydro Station continuously manned 21 For Information Only

Standby Shutdown Facility and Protected Service Water System Standby Shutdown Facility Provides an alternate means to achieve and maintain the ONS units in safe shutdown conditions Provides additional defense in depth protection by serving as a backup to existing safety systems Includes a dedicated power system including a diesel generator Credited to mitigate Station Blackout, and other non design basis events Mission time is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Manned continuously during dual KHU outages Protected Service Water Alternate power path to connect the SSF switchgear, with sufficient capacity to operate SSF equipment in the event of a failure of the SSF diesel generator Commissioned and turned over to Operations on August 2, 2013 22 For Information Only

Risk Reduction Measures

- Regulatory Commitments Duke Energy commits to the following:

ONS will not start the extended single KHU outage or a dual KHU outage if severe weather conditions are forecast.

ONS will contact the system load dispatcher once per day to ensure no significant grid perturbations (high grid loading not able to withstand a single contingency of line or generation outage) are expected during extended TS completion time.

ONS will avoid 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. In addition, no discretionary switchyard maintenance will be performed.

ONS will verify that TS required systems, subsystems, trains, components, and devices that depend on the remaining power sources are operable and preclude subsequent nondiscretionary testing or maintenance activities on these systems, subsystems, trains, components, and devices during the extended TS completion time.

ONS will control the steam

-driven emergency feedwater pump(s) as "protected" equipment during the extended TS completion time.

ONS will continuously staff the SSF during the dual KHU outages.

23 For Information Only

Other Risk Reduction Measures Critical Activity Plan, approved by the Plant Operations Review Committee prior to implementation, used for risk management. Plan will include the following risk reduction measures: LCT and Central Switchyard protected 2 nd LCT protected and available within one hour Two Jocassee Hydro Units available either of which can be aligned to the Oconee 230kV Yellow Bus within approximately one hour Temporary DG located at Keowee Hydro Station with capability to restore available KHU unit to operable status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> from dual KHU outage Reduced RCS Inventory not permitted during dual KHU outage Temporary Diesel-Driven Hale pump available to feed each unit's steam generators PSW equipment installed to backup SSF 24 For Information Only

Diverse Backup Power Sources Guideline Lee CT Jocassee Hydro Station Backup power source available to the inoperable EDG to maintain defense-in-depth philosophy of electrical design Permanently installed power source located south of ONS required by TSs when KHUs are OOS to maintain defense-in-depth. Second Lee CT available

. Nearby hydro facility located north of ONS.

Connects directly to ONS 230 kV switchyard (opposite side of ONS site from CT5/Lee CT connection

). Supplemental source must be capable of bringing unit to safe S/D for LOOP w/single failure Lee CTs rated for 41 MW each with capacity for all three ONS unit's LOOP loads. Procedures require it be connected to safety buses prior to entering extended TS completion time. 2 nd Lee CT available should an issue with the 1 st Lee CT occur. Jocassee Hydro Units (2) are rated for 195 MW each and have capacity for all 3 ONS Unit's LOOP loads.

The power source can be either a DG, gas or CT, or power from nearby hydro unit. Lee CT site is a two unit combustion turbine site. Either CT (7C or 8C) are fully capable to supply ONS LOOP loads. The use of Lee CTs exists in the normal & abnormal operating procedures.

Jocassee Hydro Station is a nearby hydro station north of Oconee. The Jocassee unit is rated for 195 MW with capability to supply ONS LOOP loads. Provision to use Jocassee Units as a backup power source for ONS exists in the station emergency operating procedures.

25 For Information Only

Diverse Backup Power Sources

26 For Information Only Guideline Lee CT Jocassee Hydro Station Time to make supplemental power source available, including cross connects, should be approximately one hour (to enable restore battery chargers and RCS inventory).

Lee CT is connected to ONS safety busses prior to extended TS completion time. A second Lee CT is available and can be connected within one hour. ONS batteries sized for 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> duty for SBO. Jocassee Hydro is available and can be connected to ONS safety bus (230 kV Yellow bus) within approximately one hour. ONS batteries sized for 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> duty for SBO.

Power source verified w/in last 30 day of extended AOT (operate and bring to rated V&F for 5 min ensuring all support system operational).

Lee CT verified every shift as available. Tested often to ensure support system work.

Used frequently for commercial generation. Source will be verified available and tested prior to extended outage.

To allow one hour time to make available plant must assess ability to cope for loss of power for one hour independent of AAC source.

ONS is 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> coping site and can maintain the site in safe stable condition independent of AAC sources. TDEFWP available and protected during outage. SSF will be verified operable prior to extended TS completion time and protected during the dual KHU portion of this outage. Temporary DG at KHS available to restore UG hours) if necessary.

ONS is 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> coping site and can maintain the site in safe stable condition independent of AAC sources. TDEFWP available and protected during outage. SSF will be verified operable prior to extended TS completion time and protected during the dual KHU portion of this outage. Temporary DG at KHS available to

Diverse Backup Power Sources 27 For Information Only Guideline Lee CT Jocassee Hydro Station The TS must contain RA and CT to verify the supplemental source is available prior to entering extended AOT TS 3.8.1 Required Action C.2.2.1 requires both standby buses to be energized by LCT prior to entering extended outage time. Regulatory Commitment

- include requirement in Critical Activity Plan Availability of power source shall be checked once per shift Continuous since LCT is energizing standby bus. Spare LCT checked shiftly. Regulatory Commitment

- include requirement in Critical Activity Plan If supplemental source becomes unavailable then enter the LCO and follow the SD actions The 2 nd Completion Time of Required Action C.2.2.1 requires the standby buses to be re-energized within one hour. If not met, entry into Condition M and shutdown of all three ONS units required. Regulatory Commitment

- include requirement in Critical Activity Plan to require action be initiated immediately to restore Jocassee capability AOT limited to 14 days (typical for DG rebuild). Licensee must provide justification for duration of the requested AOT (actual hours plus margin based on plant specific past OE)

N/A Note: Keowee not typical DG. Actual schedule plus contingency results in 62 days. Extensive planning using hydro and nuclear subject matter experts to minimize outage time.

N/A Summary Generator pole rewind work is needed and will improve equipment reliability for emergency power system.

Generator pole rewind outages scheduled for January 2014 and July 2014 Staff approval of LAR is essential to allow Duke Energy to implement KHU reliability improvements in January Significant reduction in dual KHU and single KHU outage duration reduces risk.

Additional diverse backup power sources result in electrical system defense

-in-depth that provides level of protection equivalent with BTP guidelines Additional risk reduction measures will be implemented and managed by critical activity plan Risk reduction from the installation of a temporary diesel generator is < 1E-08 ICCDP Staff approval of LAR is essential to allow Duke Energy to implement KHU reliability improvements in January and July 28 For Information Only

Closing Comments Scott Batson ONS Vice President 29 For Information Only