ML13336A545

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
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 For Information Only 5

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 For Information Only 6

Generator Pole Rewind Project For Information Only 7

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

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.

For Information Only 9

Keowee Generator Pole Rewind Outage Timeline Original 75 Days - Total Work Window Final balance run 1 day 1.7 days - Dewater 1.7 days - Dewater 1 day balance (2 days) contingency Dual KHU Outage Dual KHU Outage runs balance runs 15 days contingency Finish 35 days physical work for physical work 7.7 days outage

.83 day balance shots 4.7 days

.83 day contingency contingency (dual KHU outage) testing balance shots (dual problems KHU outage)

Revised 62 Days - Total Work Window 1.7 days 2.1 days--Dewater Dewater Start 1.7 days - Dewater Dual KHU Outage Dual KHU Outage Finish 4 days testing 10 days contingency 35 days physical work for physical work 5.6 days outage contingency 4 days balancing Risk Reduction

• Single KHU outage duration reduced from 75 days to 62 days Note: Risk Mitigation Plans will preclude entering dual unit

• 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 /> outage if severe weather is forecast in the area For Information Only 10

ONS Electrical Distribution System SYI: TRAINING USE ONLY SYI: - Starts Keowee units SYI Complete: PCB 21, 24, 58 & 59 must be closed

- UV or UF on same 2/3 - Isolates Yellow bus ELECTRICAL Distribution All required brkrs open before the auto/man switch is placed in ELECTRICAL Yellow and Red buses 230 KV bus L.O.

- Feeds S/U Xfmrs via overhead path Allows PCB 9 to close DRAWING # OP-OC-EL-EPD-2 rev 2 OR overrides SYI. auto to arm the rapid bus Xfer. If not, a Disconnect (ACB 1 or 2 and 18, 27, 30 close) Allows ACB 1 & 2 to close open DRAWN BY: SRS DATE: 9/21/10

- Yellow bus <227.468 Kv slow bus Xfer will occur (i.e. lose DISTRIBUTION

- Opens RCP brkrs from S/U Xfmr ASBURY for > 9 sec and ES 1 or 2 ( NORTH secondary but RCPs stay on) unless the NEWPORT Disconnect

REFERENCE:

700 series O Drawings (Aux still feeds) ( CENTRAL) ( CENTRAL)

GREENVILLE)

OCONEE CALHOUN switch is cycled to man and back to auto. closed APPROVED BY: Signature On File DACUS KATOMA SOUTH HALL KEOWEE OVERHEAD B W B W B W 230 KV 525 KV SWYD Xfmrs and L.C.s are RED BUS RED BUS Red / Yellow Bus Differential L.O.

pwrd from 1TE & 2 TE.

230- must be manually reset.

AUTO 525- Auto resets when PCBs open.

4 7 10 13 16 19 22 28 31 TRANSFORMER 54 57 60 1 2 KEOWEE HYDRO 2 1 7C Lee CT 34 Switchyard 8 11 14 17 20 23 26 55 58 61 8C 100KV CT 40 4 3 4T 5T 11 12 Opens on SYI . 9 12 15 18 21 24 27 30 33 13 Gen 2 Gen 1 56 59 Recloses after

8. 5 sec. LCT - can be started w/ I 1 hr.

ACB 1 or 2 YELLOW BUS YELLOW BUS OCB TCC operates AUXILIARY AUXILIARY 22. 6 Miles brkrs.

close 11 sec POWER SYSTEM W B Central 41 POWER SYSTEM after SYI to B3T JOCASSEE to B4T White Central complete CS Switchyard 90 100 KV SL1 & SL2 TRIP INTERLOCK DEFEAT CH1 OCB CENTRAL LEE 35

13. 8 KV UNDERGROUND FEEDER

8. 5 Miles Aux Xfmr is sized for Fant OCB CT5 BUS 1 its own unit loads Black AUTO / MAN 101 Main Transformer plus 2nd unit ES loads Main Transformer Main Transformer 1T CT1 2T CT2 3T CT3 CT4 CT5 Aux Transformer Startup Transformer Aux Transformer Startup Transformer Aux Transformer Startup Transformer 6900 6900 4160 6900 4160 6900 4160 6900 6900 4160 4160 4160 Main Generator Main Generator Main Generator SL1/ 2 Trip Unit #1 Unit #2 Unit #3 Interlock Defeat switch If Auto/ Man switch In Central :

left in the Man always has position , E brkr degraded grid 4160 EMERGENCY STARTUP BUS still auto swaps on protection unit trip . Auto/Man 6900 STARTUP BUS In Auto :

MFB2 always has NORMAL AUTO/MAN UV protection SOURCE TO M 1TA 1TB A

U AN Close on SYI with ES or MFBMP SK1 SK2 SL1 SL2 1A1 1B1 1A2 1B2 timed out SL 1& 2 are RCP RCP RCP RCP 2TA 2TB 3TA 3TB manual brkrs

( no auto closure)

STARTUP SOURCE If Auto/Man NORMAL SOURCE 2A1 2B1 2A2 2B2 3A1 3B1 3A2 3B2 Transfer switch must RCP RCP RCP RCP RCP RCP RCP RCP switch left in be in manual to close STARTUP SOURCE the mid STARTUP SOURCE SL 1 & 2 brkrs .

NORMAL SOURCE postion, CT 4/ 5 rated for ES prevents E loads from 1 unit plus STANDBY BUS #1 Load Shed loads from brkr from auto swapping on STANDBY BUS #2 other 2 units .

unit trip. 4160/ 600 AUXILIARY SERVICE SWITCHGEAR FROM 4T FROM 5T Loss if pwr to 4T/5 T N1 N2 E1 E2 S1 S2 N1 N2 E1 E2 S1 S2 N1 N2 E1 E2 S1 S2 will cause auto swap MFB #1 MFB #1 MFB #1 of B3T/B4 T to alt MFB #2 MFB #2 MFB #2 NORMAL ALTERNATE NORMAL pwr supply Unit 1 Unit 2 Unit 3 ASWP UNIT HPIP HPIP HPIP 1&3 B3T X 5 & X 6 Load Shed if all the 1TC 1TD 1TE B A PRIMING 2TC 2TD 2TE SSF 3TC 3TD 3TE B4T following:

PUMP OTS1 - Load shed signal (SBCI)

HPSWP HPSWP AUXILIARY POWER SYI causes 1 sec SBCI : LOCA Load Shed occurs on ES and CRD Trip Confirm. Limits & Precautions: SYSTEM - SL Brkrs closed delay in closing E Must have Load Shed: Purpose : to reduce post LOCA Rx trip voltage dip by Cross- connection between transformers (1,2,3) T and CT-(1,2,3 ) through the 4160 V buses 1X7 , 2X 4 & 3X 4 - No ES brkrs to prevent Prevents closing E brkrs tripping 4kv , nonsafety related , secondary system pump should be limited to the time required to perform a normal transfer of auxiliary loads. Always Load Shed and come PIAC C&D Automatically come back after closing out of phase . Allows closing S brkrs motors in the event of LOCA or inside cntmt MSLB with Extended cross- connection could backcharge the transformer with the lower output voltage back after 60 sec ( even if pwr Chillers 30 seconds.

offsite pwr . Resets automatically after 10 seconds . and create an overcurrent condition with the buses and/ or associated breakers. not restored yet)

For Information Only 11

ONS Transmission Lines Oconee Nuclear Oconee NuclearStation Station For Information Only 12

Defense-in-Depth - Multiple Diverse Backup Power Sources Keowee Outage Timeline 62 Days - Total Work Window Start 1.7 days - Dewater Finish Dual KHU Outage 1.7 days - Dewater 5.6 days Dual KHU Outage 10 days contingency 4 days 4 days outage for physical work 35 days physical work balancing testing contingency 9 offsite power sources available Underground (U/G) KHU 1 Lee CT running and energizing Standby Buses nd 2 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 /> SSF Operable (including SSF DG)

Two Jocassee Hydro Units available within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Temporary Diesel Generator at Keowee for restoring KHU associated U/G Path Temporary diesel-driven feedwater pump (Hale Pump)

PSW Power System installed for use to SSF existing additional For Information Only 13

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 For Information Only 14

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 For Information Only 15

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 For Information Only 16

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 For Information Only 17

Lee Combustion Turbines For Information Only 18

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 For Information Only 19

Jocassee Hydro Station For Information Only 20

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 For Information Only 21

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 For Information Only 22

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.

For Information Only 23

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 2nd 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 units steam generators PSW equipment installed to backup SSF For Information Only 24

Diverse Backup Power Sources Guideline Lee CT Jocassee Hydro Station Backup power source available to the Permanently installed power source located Nearby hydro facility located north of ONS.

inoperable EDG to maintain defense-in- south of ONS required by TSs when KHUs are Connects directly to ONS 230 kV switchyard depth philosophy of electrical design OOS to maintain defense-in-depth. Second Lee (opposite side of ONS site from CT5/Lee CT CT available. connection).

Supplemental source must be capable Lee CTs rated for 41 MW each with capacity for Jocassee Hydro Units (2) are rated for 195 MW of bringing unit to safe S/D for LOOP all three ONS units LOOP loads. Procedures each and have capacity for all 3 ONS Units w/single failure require it be connected to safety buses prior to LOOP loads.

entering extended TS completion time. 2nd Lee CT available should an issue with the 1st Lee CT occur.

The power source can be either a DG, Lee CT site is a two unit combustion turbine Jocassee Hydro Station is a nearby hydro gas or CT, or power from nearby hydro site. Either CT (7C or 8C) are fully capable to station north of Oconee. The Jocassee unit is unit. supply ONS LOOP loads. The use of Lee CTs rated for 195 MW with capability to supply ONS exists in the normal & abnormal operating LOOP loads. Provision to use Jocassee Units procedures. as a backup power source for ONS exists in the station emergency operating procedures.

For Information Only 25

Diverse Backup Power Sources Guideline Lee CT Jocassee Hydro Station Time to make supplemental power Lee CT is connected to ONS safety busses prior Jocassee Hydro is available and can be source available, including cross to extended TS completion time. A second Lee connected to ONS safety bus (230 kV Yellow connects, should be approximately CT is available and can be connected within one bus) within approximately one hour. ONS one hour (to enable restore battery 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 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.

chargers and RCS inventory). SBO.

Power source verified w/in last 30 day Lee CT verified every shift as available. Tested Used frequently for commercial generation.

of extended AOT (operate and bring to often to ensure support system work. Source will be verified available and tested prior rated V&F for 5 min ensuring all to extended outage.

support system operational).

To allow one hour time to make 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 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 available plant must assess ability to site in safe stable condition independent of AAC site in safe stable condition independent of AAC cope for loss of power for one hour sources. TDEFWP available and protected sources. TDEFWP available and protected independent of AAC source. during outage. SSF will be verified operable during outage. SSF will be verified operable prior to extended TS completion time and prior to extended TS completion time and protected during the dual KHU portion of this protected during the dual KHU portion of this outage. Temporary DG at KHS available to outage. Temporary DG at KHS available to restore UG unit ( 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) if necessary. restore UG unit ( 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) if necessary.

For Information Only 26

Diverse Backup Power Sources Guideline Lee CT Jocassee Hydro Station The TS must contain RA and CT to TS 3.8.1 Required Action C.2.2.1 requires both Regulatory Commitment - include requirement in verify the supplemental source is standby buses to be energized by LCT prior to Critical Activity Plan available prior to entering extended entering extended outage time.

AOT Availability of power source shall be Continuous since LCT is energizing standby bus. Regulatory Commitment - include requirement in checked once per shift Spare LCT checked shiftly. Critical Activity Plan If supplemental source becomes The 2nd Completion Time of Required Action Regulatory Commitment - include requirement in unavailable then enter the LCO and C.2.2.1 requires the standby buses to be re- Critical Activity Plan to require action be initiated follow the SD actions energized within one hour. If not met, entry into immediately to restore Jocassee capability Condition M and shutdown of all three ONS units required.

AOT limited to 14 days (typical for DG N/A N/A rebuild). Licensee must provide Note: Keowee not typical DG. Actual schedule justification for duration of the plus contingency results in 62 days. Extensive requested AOT (actual hours plus planning using hydro and nuclear subject matter margin based on plant specific past OE) experts to minimize outage time.

For Information Only 27

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 For Information Only 28

Closing Comments Scott Batson ONS Vice President For Information Only 29