ML110180609

Enclosure 1, Oconee Nuclear Station, Major Project Plans

ML110180609
Person / Time
Site:	Oconee
Issue date:	01/05/2011
From:	Duke Energy Carolinas
To:	NRC/RGN-II
Shared Package
ML110180609	List: ML110180609
References
Download: ML110180609 (10)

Text

OFFICIAL USE ONLY - SECURRITY RELATED INFORMATON Major Project Plans January 5, 2011 Oconee Nuclear Statio on Withhold from Public Disclossure under 10 CFR 2.390 For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECURRITY RELATED INFORMATON External Flood Regulatory Status Interim Actions in place; enforcced by CAL Work ongoing to achieve comm mon understanding of; Analysis parameters for base case, and Safety significance Project Status All Interim Actions implemented per commitments Self Assessment of Interim Acttions completed p in May y 2010 NRC Inspection of Interim Actions completed in June 2010 FERC Stop Work on tempora ary Intake Diversion Wall cleared Design study of potential modiffications nearing completion Need confirmation of design inputs Parallel work has eliminated so ome options and focused efforts Risk Benefit Small (<1E-06 / yr) - actual riskk improvement Cost

~$ 4 M to date - analyses and interim actions only Withhold from Public Disclossure under 10 CFR 2.390 2

For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECUR RITY RELATED INFORMATON External Flood CAL Commitments No. Compensatory Meas sures Implementation Status Perform flooding studies using the Hydrologic Engineering Ce enter-River Complete Analysis System (HEC-1 RAS) model for comparison with previous DAMBRK models to o more accurately represent anticipated flood Complete heights in the west yard following a postulated failure of the Jo ocassee Dam.

Maintain plans, procedures (Jocassee and Oconee) and guida ance documents implemented (Oconee) to address mitigation of postulated flood events which could rend der the Standby Shutdown facility inoperable 2 and are consistent with current perspectives gained following the HEC-RAS sensitivity studies and the Complete subsequent 2D inundation studies. To the extent practical, the mitigation strategy is similar to existing extensive plant damage scenario (B.5.b) equipment methods and criteria.

Duke Energy Hydro generation will create a guidance docume ent to consolidate river management and 3 C Complete storm management processes. (includes the Jocassee Develo opment and the Keowee Development.)

Maintain a dam safety inspection program that includes: (1) weekly w dam safety inspections of the Jocassee Dam by Duke Energy personnel, (2) dam safety insspections following any 2-inch or greater 4 rainfall or felt seismic event, (3) annual dam safety inspectionss by Duke Energy, (4) annual dam safety Complete inspections by FERC representatives, (5) five year safety insp pections by FERC approved consultants, and (6) five year underwater inspections.

Maintain a monitoring program that includes: (1) continuous remote r monitoring from Hydro Central 5 Operating Center in Charlotte, NC, (2) monthly monitoring of observation wells, (3) weekly monitoring of Complete seepage monitoring points, and (4) annual surveys of displace ement monuments.

6 Assign an Oconee engineer as Jocassee Dam contact to heig ghten awareness of Jocassee Dam status. Complete 7 Install ammeters and voltmeters on Keowee spillway gates for equipment condition monitoring. Complete Withhold from Public Disclossure under 10 CFR 2.390 3

For Information Only OFFICIAL USE ONLY - SECURITY Y RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECUR RITY RELATED INFORMATON External Flood CAL Commitments No. Compensatory Meas sures Implementation Status Ensure forebay and tailrace level alarms are provided for Joccassee to support timely detection of a 8 Complete developing dam failure.

Add a storage building adjacent to the Jocassee spillway to house h the backup spillway gate operating 9 Complete equipment (e.g., compressor and air wrench).

Obtain and stage a portable generator and electric drive mottor near the Jocassee spillway gates to 10 Complete serve as a second set of backup spillway gate operating equ uipment.

Conduct Jocassee Dam failure Table Top Exercise with Oco onee participation to exercise and improve 11 Complete response procedures.

Instrument and alarm selected seepage monitoring locationss for timely detection of degrading 12 Complete conditions.

Provide additional video monitoring of Jocassee Dam (e.g. dam toe, abutments, and groin areas) for 13 Complete timely assessment of degrading conditions 14 Add equipment to provide third means of operating Jocassee e spillway gates Complete Conduct Jocassee Dam/Oconee Emergency Response Orga anization Drill to exercise and improve 15 Complete response procedures.

Withhold from Public Disclossure under 10 CFR 2.390 4

For Information Only OFFICIAL USE ONLY - SECURITY Y RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECURRITY RELATED INFORMATON Feasibility /

Constructability Study Study has been pursued in parallel with implementation of Compensatory Measures.

Sensitivity analyses have eliminated some potential solutions Compatibility with other safe shutdown strategies (Fire, HELB, tornado) factored into consideration of potential solutions First milestone has not been met Frrom 12/2/2009 presentation Withhold from Public Disclossure under 10 CFR 2.390 5

For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECURRITY RELATED INFORMATON Feasibility /

Constructability Study Disposition of concepts from f 11/30/09 letter Flood Mitigation device located in the Oconee Intake Canal Required hardening of backk side of Intake Dike to prevent erosion Did NOT resolve second p pe eak flooding g of west yyard Downstream modificatio ons (earth removal) to flood zone to smooth flow through the t Keowee Tailrace Sensitivity study demonstra ated little benefit and high cost; eliminated from consideration Assured integrity of porttion of the Oconee Intake Canal Dike to preclude failure of the dike toward the SSF Temporary wall in place; pe ermanent wall listed in 11/29/10 letter Withhold from Public Disclossure under 10 CFR 2.390 6

For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECUR RITY RELATED INFORMATON Feasibility /

Constructability Study Disposition of concepts from f 11/30/09 letter Diversion Wall located on o the north rim of the Oconee Intake Canal Dike Temporary wall in place; pe ermanent wall listed in 11/29/10 letter Protection of the SSF fo or higher inundation levels Purchase specification for submarine s doors developed Increase in wall height was also considered; submarine doors preferred Use of 100 kV line to powerr SSF instead of diesel increases margin Listed in 11/29/10 letter Water retaining structure e/wall/raised roadbed in swale adjacent to the World off Energy Visitors Center Permanent wall installed Withhold from Public Disclossure under 10 CFR 2.390 7

For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECUR RITY RELATED INFORMATON Feasibility /

Constructability Study List of modifications in 11/29//2010 letter Provide a flood diversion walll on the north portion of the Oconee Intake Dike. (requires approval by the Federal Energy Regulatory Commission (FERC))

Provide a flood protected (i.e e. will be available during and after the postulated inundation) offsite e electrical power source to the SSF sufficient to support operation of the SSF related equipment without reliance on operation of the SSF S diesel generator.

Provide flood protection for SSF S related Structures, Systems, and Components (SSCs), excluding the SSF diesel generator and its support systems, sufficient to o ensure they are capable of performing their safe shutdown functionss for the flood conditions in which they are expected to operate.

Provide makeup water to and d boration of the spent fuel pools sufficient to support extended d operation of the SSF and maintain the spent fuel pools in a safe con ndition.

Withhold from Public Disclossure under 10 CFR 2.390 8

For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECURRITY RELATED INFORMATON Feasibility /

Constructability Study April 2011 Submittal Contentts Modification Descriptions Design Inputs Scope Description Implementation Schedule To meet schedule schedule, team is moving forward with assumption that Case 2 2, as described in 8/20/2010 submittal, s is base case.

Withhold from Public Disclossure under 10 CFR 2.390 9

For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1

OFFICIAL USE ONLY - SECURRITY RELATED INFORMATON Action Items and Closing Remarks NRC Duke Energy Withhold from Public Disclossure under 10 CFR 2.390 10 For Information Only OFFICIAL USE ONLY - SECURITYY RELATED INFORMATON Enclosure 1