ML12066A037

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Revision to Tornado/Helb Mitigation Strategies and Regulatory Commitments
ML12066A037
Person / Time
Site: Oconee  Duke Energy icon.png
Issue date: 02/21/2012
From: Gillespie T
Duke Energy Carolinas
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML12066A037 (15)


Text

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T. PRESTON GILLESPIE, JR.

Vice President

  • Energy Oconee Nuclear Station Duke Energy ONO VP / 7800 Rochester Hwy.

Seneca, SC 29672 February 21, 2012 864-873-4478 864-873-4208 fax Document Control Desk T.Gillespie@duke-energy.com U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Duke Energy Carolinas, LLC Oconee Nuclear Station, Units 1, 2, and 3 Docket Numbers 50-269, 50-270, and 50-287, Renewed Operating Licenses DPR-38, DPR-47, and DPR-55 Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments

References:

1. Letter to the Nuclear Regulatory Commission from Henry B. Barron (Duke Energy) dated November 30, 2006, "Tornado/HELB Mitigation Strategies and Regulatory Commitments."
2. Letter to the Nuclear Regulatory Commission from T.P. Gillespie (Duke Energy) dated December 16, 2011, "Tornado and High Energy Line Break (HELB)

Mitigation License Amendment Requests (LARs) - Responses to Request for Additional Information."

This letter documents Duke Energy Carolinas, LLC (Duke Energy) notification to the Nuclear Regulatory Commission (NRC) of a revision to the tornado and high energy line break (HELB) mitigation strategy commitments originally documented in and last revised in references 1 and 2, respectively.

Vendor equipment delivery and document completion schedules have resulted in challenges to engineering change package preparation and associated licensing activities.

These challenges have caused Duke Energy to defer the final portion of the Protected Service Water System implementation from July 31, 2012 to December 31, 2012. The basis for this change was discussed with NRC management on February 9, 2012. The associated commitment is 8T. An updated status of the tornado and HELB related commitments are given in the Enclosure to this letter.

The revised implementation schedule coordinates the removal of the Station Auxiliary Service Water (ASW) pump and switchgear, replacement with the Protected Service Water (PSW) system pumps, and post-modification testing of the PSW system with Unit l's Fall 2012 refueling outage. Much of the major infrastructure elements of the PSW system remain in-progress and are scheduled to be completed by July 31, 2012, i.e., the PSW building equipment installation and power up, followed by completion of the backup power feed to the Standby Shutdown Facility.

Duke Energy remains committed to the completion of this project and recognizes its contribution to resolution of outstanding tornado, HELB, and fire protection regulatory issues as well as its significant positive impact on the station's probabilistic risk assessment margin. As such, the project team's goal is to complete the PSW project as www. duke-energy.com

Nuclear Regulatory Commission Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments February 21, 2012 Page 2 soon as reasonably achievable. In no case will safety or quality be compromised for the sake of schedule.

If you have any questions in regard to this letter, please contact Stephen C. Newman, Regulatory Compliance Senior Engineer, Oconee Nuclear Station, at (864) 873-4388.

Sincerely, T. Preston Gillespie, Jr.,

Vice President, Oconee Nuclear Station Enclosure

Nuclear Regulatory Commission Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments February 21, 2012 'Page 3 cc (w/enclosure):

Mr. John F. Stang, Project Manager Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 8 G9A Washington, D. C. 20555 Mr. Victor M. McCree, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Mr. Andrew T. Sabisch NRC Senior Resident Inspector Oconee Nuclear Station Ms. Susan E. Jenkins, Manager Radioactive & Infectious Waste Management SC Dept. of Health and Environmental Control 2600 Bull St.

Columbia, SC 29201

Nuclear Regulatory Commission Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments February 21, 2012 Page 4 bcc (w/enclosure):

J. W. Pitesa T. P. Gillespie, Jr.

D.A. Baxter S. L. Batson R. J. Freudenberger R. H. Guy T. D. Ray T. L. Patterson K. R. Alter E. S. Lynch D. K. Mc Rainey F. T. Rickenbaker J. E. Burchfield D. A. Coyle T. D. Mills C. W. Williams G. K. Mc Aninch J. A. Patterson T. D. Brown C. J. Thomas - NRI&IA R. D. Hart - CNS K. L. Ashe - MNS NSRB, EC05N ELL, EC050 File - T.S. Working ONS Document Management

Enclosure Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments

Enclosure - Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments February 21, 2012 Page 2 No. Tornado Commitments Due Date Complete (Y/N) 1T U3 Control Room North Wall Modification. - Y 2T SSF Diesel Fuel Vent Modification. - Y 3T SSF and CT-5 Trenches Intersection Modification SSF - Y Trench at north end of SSF (TORMIS).

4T Borated Water Storage Tank Modifications. - Y 5T West Penetration Room (WPR) and Cask - Y Decontamination Tank Room (CDTR) Wall Modifications.

6T Fiber Reinforced Polymer (FRP) LAR for strengthening - Y selected masonry walls for tornado wind and AP.

7T Tornado Mitigation Strategy LAR. - Y 8T PSW/HPI modifications. 12-2012 N 9T Missile inventory program developed. Y 10T Verbally notify in advance the Deputy Director, Division of 6-2016 N Reactor Licensing of the NRC, followed by a written communication, of significant changes in the scope and/or completion dates of the commitments. The notification will include the reason for the changes and the modified commitments and/or schedule.

11T Installation of MSIVs. Ul: 12-2014 N 12T U2: 12-2015 13T U3: 06-2016 14T Fiber Reinforced Polymer (FRP) LAR for strengthening - Y selected "brick" masonry walls for tornado wind and AP.

15T Analyze the double column set which support each unit's - Y Main Steam lines outside of the containment building, and provide modifications, as necessary, to meet tornado criteria 16T Physically protect the Atmospheric Dump Valve's (ADV's) Ul: 12-2014 N function per RG 1.76, Rev. 1. U2: 12-2015 U3: 06-2016 17T Improve protection of the Standby Shutdown Facility 12-31-2013 N (SSF) double doors (large 8'xl 2' doors located on the south side of the SSF structure) per UFSAR SSF tornado criteria.

18T Revise and clarify the tornado LB description as After N documented in UFSAR Section 3.2.2; add the TORMIS issuance of methodology results to UFSAR Section 3.5.1.3, and the SER.

correct inaccurate tornado design information for the Auxiliary Building Cable and Electrical Equipment Rooms

Enclosure - Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments February 21, 2012 Page 3 No. Tornado Commitments Due Date Complete (Y/N) as described in UFSAR Table 3-23.

19T The SSF BASES for TS 3.10.1 will be clarified to address After N degradation of passive civil features as not applying to issuance of operability under Technical Specifications Limiting the SER.

Condition for Operation (TS LCO) 3.10.1, "Standby Shutdown Facility," but rather as UFSAR commitments outside of the ONS TS.

20T 1 Duke Energy will perform qualification testing and Y reporting in accordance with ICC AC125 [Reference 5 of Enclosure 2] for the selected FRP System.

21T Duke Energy will perform and document a technical Y evaluation of the FRP system (fibers and polymeric resin) in accordance with Duke Energy's Supply Chain Directive SCD230 [Reference 7 of Enclosure 2] to demonstrate that:

1. The item qualifies as a commercial grade item.
2. The supplier is capable of supplying a quality product.
3. The quality of the item can be reasonably assured.

22T Duke Energy will utilize technical procedures to control Y testing of concrete substrate and installation and inspection of the FRP system in accordance with ICC AC125 [Reference 5 of Enclosure 2], ACI 440.2R-02

[Reference 6 of Enclosure 2], and ICC AC178 [Reference 8 of Enclosure 2].

23T Duke Energy will perform long-term inspection of the FRP Y system as described in UFSAR Section 18.3.13 and [see 27T]

EDM-410, and in accordance with ICC AC125 [Reference 5 of Enclosure 2], ACI 440.2R-02 [Reference 6 of Enclosure 2], and ICC AC178 [Reference 8 of Enclosure 2], on a nominal 5 year interval. This inspection frequency may be reduced to a nominal 10 year interval with appropriate justification based on the structure, environment, and previous long-term inspection results.

Inspections of the installed FRP system will include:

  • visual inspections of test walls and selected portions of WPR walls for changes in color, debonding, peeling, blistering, cracking, crazing, deflections and other anomalies; and,

" tension adhesion testing of cored samples taken from test walls using methods specified in ASTM D4541 1 Tornado commitments 20-23 originate from the FRP LAR dated 6-1-2006 (NRC SER dated 2-21-2008).

Enclosure - Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments February 21, 2012 Page 4 No. Tornado Commitments Due Date Complete (Y/N)

[Reference 9 of Enclosure 2] or ACI 530R-02

[Reference 16 of Enclosure 2].

24T 2 Duke Energy will perform qualification testing and - Y reporting in accordance with ICC AC125 [Approved 10/2006, Effective 1/1/2007] for the selected FRP System.

25T Duke Energy will perform and document a technical Y evaluation of the FRP system (fibers and polymeric resin) in accordance with Duke Energy's Supply Chain Directive SCD230 [Reference 7 of Enclosure 2] to demonstrate that:

  • The supplier is capable of supplying a quality product.
  • The quality of the item can be reasonably assured.

26T Duke Energy will utilize technical procedures to control Y testing of concrete substrate and installation and inspection of the FRP system in accordance with ICC AC125 [Approved 10/2006, Effective 1/1/2007], ACI 440.2R-02 [Effective 7/1/2002], and ICC AC178

[Approved 6/2003, Effective 7/1/2003, editorially revised 6/2008].

27T Duke Energy will implement a long-term inspection Prior to N program of the FRP system that will be described in startup from UFSAR Section 18.3.13 and EDM-410, meet the the Unit 3 requirements of ICC AC125 [Approved 10/2006, Effective Spring 2012 1/1/2007], ACI 440.2R-02 [Effective 7/1/2002], and ICC refueling AC178 [Approved 6/2003, Effective 7/1/2003, editorially outage.

revised 6/2008], on the following schedule: at each unit's outage cycle for the first six years from 2012 through 2017, then, if justified based on no observed FRP degradation, transition to every-other outage cycle for the next four years from 2018 through 2021, then, if justified based on continued no observed FRP degradation, transition to every third outage cycle thereafter from 2022 until end of license in July 2034. Inspections of the installed FRP system will include:

  • visual inspections of test walls and portions (both random and controlled locations) of WPR in-service walls for changes in color, 2 Tornado commitments 20-26 are addressed in the NRC's FRP SER for brick masonry dated 6-27-2011. The completion status has been updated for several of the commitments.

Enclosure - Revision to Tornado/HELB Mitigation Strategies and Regulatory Commitments February 21, 2012 Page 5 No. Tornado Commitments Due Date Complete (Y/N) debonding, peeling, blistering, cracking, crazing, deflections and other anomalies;

  • tension adhesion testing of cored samples taken from designated test walls using methods specified in ASTM D7234; and,
  • visual inspections of mortar joints located along the bottom edge of FRP-strengthened masonry walls.

For each inspection interval, the portions of FRP-strengthened masonry walls to be inspected will be chosen in accordance with a sampling plan developed from guidance provided by a) Draft Regulatory Guide DG-1070, "Sampling Plans Used for Dedicating Simple Metallic Commercial Grade Items for use in Nuclear Power Plants", and b) EPRI NP-7218 document "Guidelines for the Utilization of Sampling Plans for Commercial Grade Item Acceptance" (NCIG-19), as implemented at ONS by Supply Chain Directive SCD-290

[(new) Reference 21 of Enclosure 2].

Note: This response replaces the five (5) year inspection commitment made in FRP LAR (No. 2009-05) dated June 29, 2009, and will apply to the FRP application for both block and brick.

28T Duke Energy will install mechanical shear restraints along Y the brick masonry wall perimeter (top and sides only) and block masonry wall perimeter (top only) to remediate potentially limiting conditions of construction.

29T Duke Energy will incorporate the FRP testing and Y inspection program into Oconee Nuclear Station's Aging Management Program.

30T As discussed with the Staff, Fyfe Company, LLC, the Y manufacturer of the FRP products, will provide Duke Energy with a Certificate of Compliance certifying that both the FRP product and its installation meet all applicable requirements.

Enclosure - Revision to Tornado/HELB Regulatory Commitment Due Dates February 21, 2012 Page 6 Complete HELB Commitments Due Date (YIN)

No. (Y/N) 1H Implement an inspection program for the Aux Bldg MS - Y and FW girth and accessible attachment welds.

2H Implement an inspection program for other Aux. Bldg high - Y energy piping critical crack locations at welds.

3H Initial ASME Section XI ISI interval UT of the Aux. Bldg - Y MS and FW girth welds and accessible attachment welds.

4H Initial ASME Section Xl ISI interval UT of other Aux. Bldg - Y high energy piping critical crack locations at welds.

5H Implement an inspection program for accessible piping - Y base metal downstream of the FW isolation valves located in the EPR.

6H Implement an inspection program for accessible piping - Y base metal of other Aux. Bldg high energy piping critical crack locations not at welds.

7H Initial ASME Section XI ISI interval UT inspection of - Y piping base metal downstream of FW isolation valves located in the EPR.

8H Initial ASME Section XI ISI interval UT inspection for - Y accessible piping base metal of other Aux. Bldg high energy piping critical crack locations not at welds.

9H Implement an inspection program of accessible - Y attachment welds at the terminal ends inside the FW guard pipe.

10H Initial visual inspections of accessible attachment welds at - Y the terminal ends inside the FW guard pipe.

11H Inspect and repair the Unit 2 East Penetration Room - Y electrical penetration termination enclosures to their correct configuration. Missing and/or damaged covers, gaskets, and fasteners will be repaired or replaced.

12H Inspect and repair the Unit 1 East Penetration Room Y electrical penetration termination enclosures to their correct configuration. Missing and/or damaged covers, gaskets, and fasteners will be repaired or replaced.

13H Inspect and repair the Unit 3 East Penetration Room Y electrical penetration termination enclosures to their correct configuration. Missing and/or damaged covers, gaskets, and fasteners will be repaired or replaced.

14H Create an inspection plan to select a portion of Units 1, 2 Y and 3 enclosures to open and inspect for signs of internal debris and corrosion.

Enclosure - Revision to Tornado/HELB Regulatory Commitment Due Dates February 21, 2012 Page 7 HELB Commitments Due Date Complete No.

(Y/N) 15H Revise station procedures and processes as needed to - Y ensure penetration termination enclosures are maintained in their correct configurations.

16H Complete the design and installation of flood outlet - Y devices for the Unit 1 East Penetration Room.

17H Complete the design and installation of flood outlet - Y devices for the Unit 2 East Penetration Room.

18H Complete the design and installation of flood outlet - Y devices for the Unit 3 East Penetration Room.

19H Complete the design and installation of flood - Y impoundment and exterior door flood improvement features for the Unit 1 East Penetration Room 20H Complete the design and installation of flood - Y impoundment and exterior door flood improvement features for the Unit 2 East Penetration Room.

21 H Complete the design and installation of flood - Y impoundment and exterior door flood improvement features for the Unit 3 East Penetration Room.

22H HELB LB and Mitigation Strategy LARs. - Y 23H 24H 25H Verbally notify in advance the Deputy Director, Division of As N Reactor Licensing of the NRC, followed by a written necessary communication, of significant changes in the scope and/or until 7-2012 completion dates of the commitments. The notification will include the reason for the changes and the modified commitments and/or schedule.

26H The inlet isolation valves to the Letdown Coolers on the To be N Letdown Line (1 HP-1 & 1 HP-2) will be upgraded to permit provided to their use following a postulated HELB on the Letdown the Staff Line at Containment Penetration No. 6. With these valves upon upgraded, either could then be closed if either of the issuance of inboard containment isolation valves (1HP-3 & 1HP-4) the SER.

fails to close in order to mitigate the postulated HELB on the Letdown line.

27H The ducting near the Control Complex is being upgraded To be N with duct registers or cover plates to prevent the potential provided to propagation of the HELB generated environment in the the Staff East Penetration Room to the Control Complex. upon issuance of the SER.

Enclosure - Revision to Tornado/HELB Regulatory Commitment Due Dates February 21, 2012 Page 8 Complete HELB Commitments Due Date (opN)

No. (Y/N) 28H The valves (1 HP-1 03 & 1HP-1 07) on the individual - Y suction lines to the "A" & "B" High Pressure Injection (HPI) pumps are being upgraded to allow the remote operation (operated outside the HPI pump room) of these valves.

The remote operation of these valves allow the isolation of postulated HELBs on the discharge side of the HPI Pumps without compromising the availability of the other HPI Pumps and the need for maintaining the Letdown Storage Tank aligned to the HPI Pump suction piping.

For a single active failure of either valve 1 HP-1 03 or 1 HP-107 to close, a redundant, remotely operated valve is provided on each of the HPI Pumps "A" and "B" to assure HELB mitigation.

29H The position of several Plant Heating System isolation Y valves is being changed from "OPEN" to "CLOSED." This position change will eliminate the need to postulate Plant Heating System HELBs in the East Penetration Room and West Penetration Room, because these piping lines will isolated during normal plant conditions of the station.

30H Turbine Building structural support column D-26 will be To be N modified by adding a brace to the column. This brace is provided to necessary to prevent potential failure of the column, when the Staff subjected to a pipe whip load. This upgrade prevents the upon loss of the routing to get temporary cabling to the Low issuance of Pressure Injection and Low Pressure Service Water pump the SER.

motors.

31 H The existing Condenser Circulating Water (CCW) To be N discharge stop gates will be replaced and four (4) new provided to stop gates will be obtained. These stop gates will be the Staff used to terminate all reverse flow through HELB damaged upon Low Pressure Service Water and CCW piping. This issuance of modification is required, in order to recover from a the SER.

Turbine Building flood event caused by a postulated HELB therein.

32H Evaluate the ability of the Standby Shutdown Facility to Y perform its safety functions with a compromised main steam pressure boundary due to potential breaks in the main steam system and other HELBs.

33H Weep holes will be installed in the bottom of the outside- Y containment junction box enclosures for the Viking Electrical Penetrations. Also, the electrical penetration inspection procedure is being amended to inspect the weep holes for blockage

Enclosure - Revision to Tornado/HELB Regulatory Commitment Due Dates February 21, 2012 Page 9 Complete HELB Commitments Due Date (YIN)

No. (Y/N) 34H The inlet isolation valves to the Letdown Coolers on the To be N Letdown Line (2HP-1 & 2HP-2) will be upgraded to permit provided to their use following a postulated HELB on the Letdown the Staff Line at Containment Penetration No. 6. With these valves upon upgraded, either could then be closed if either of the issuance of inboard containment isolation valves (2HP-3 & 2HP-4) the SER.

fails to close in order to mitigate the postulated HELB on the Letdown line.

35H The Unit 2 HVAC ducting near the Control Complex is To be N being upgraded with duct registers or cover plates to provided to prevent the potential propagation of the HELB generated the Staff environment in the East Penetration Room to the Control upon Complex. issuance of the SER.

36H The valves (2HP-103 & 2HP-1 07) on the individual To be N suction lines to the "A" & "B" High Pressure Injection (HPI) provided to pumps are being upgraded to allow the remote operation the Staff (operated outside the HPI pump room) of these valves, upon The remote operation of these valves allow the isolation issuance of of postulated HELBs on the discharge side of the HPI the SER.

pumps without compromising the availability of the other HPI Pumps and the need for maintain the Letdown Storage Tank aligned to the HPI Pump suction piping.

For a single active failure of either valves 2HP-1 03 or 2HP-107 to close, a redundant, remotely operated valves is provided on each of the HPI Pumps "A" and "B" to assure HELB mitigation.

37H The position of several Unit 2 Plant Heating System Y isolation valves is being changed from "OPEN" to "CLOSED." This position change will eliminate the need to postulate Plant Heating System HELBs in the East Penetration Room and West Penetration Room, because these piping lines will be isolated during normal plant conditions of the station.

38H Turbine Building structural support Column D-29 & D-31 To be N will be modified by adding a brace to the column. This provided to brace is necessary to prevent potential failure of the the Staff column, when subjected to a pipe whip load. upon issuance of the SER.

Enclosure - Revision to Tornado/HELB Regulatory Commitment Due Dates February 21, 2012 Page 10 Complete HELB Commitments Due Date (YIN)

No. (Y/N) 39H Weep holes will be installed in the bottom of the Unit 2 - Y outside-containment junction box enclosures for the Viking Electrical Penetrations. Also, the electrical penetration inspection procedure is being amended to inspect the weep holes for blockage.

40H The inlet isolation valves to the Letdown Coolers on the To be N Letdown Line (3HP-1 and 3HP-2) will be upgraded to provided to permit their use following a postulated HELB on the the Staff Letdown Line at Containment Penetration No. 6. With upon these valves upgraded, either could then be closed if issuance of either of the inboard containment isolation valves (3HP-3 the SER.

and 3HP-4) fails to close in order to mitigate the postulated HELB on the Letdown Line.

41H The Unit 3 Auxiliary Building HVAC ducting near the Unit To be N 3 Control Complex is being upgraded with duct registers provided to or cover plates to prevent the potential propagation of the the Staff HELB generated environment in the East Penetration upon Room to the Unit 3 Control Complex. issuance of the SER.

42H The valves (3HP-103 and 3HP-107) on the individual Y suction lines to the "A" and "B" High Pressure Injection (HPI) pumps are being upgraded to allow the remote operation (operated outside the HPI pump room) of these valves. The remote operation of these valves allow the isolation of postulated HELBs on the discharge side of the HPI Pumps without compromising the availability of the other HPI Pumps and the need for maintaining the Letdown Storage Tank aligned to the HPI Pump suction piping. For a single active failure of either valve 3HP-103 or 3HP-107 to close, a redundant, remotely operated valve is provided on each of the HPI Pumps "A" and "B" to assure HELB mitigation.

43H The position of the Unit 3 Plant Heating System isolation Y valve 3AS-182 being changed from "OPEN" to "CLOSED." This position change will eliminate the need to postulate Plant Heating System HELBs in the East Penetration Room and West Penetration Room, because these piping lines will be isolated during Normal Plant Conditions of the station.

Enclosure - Revision to Tornado/HELB Regulatory Commitment Due Dates February 21, 2012 Page 11 Complete HELB Commitments Due Date (YIN)

No. (Y/N) 44H Turbine Building structural support columns M-20 (Unit 1), To be N M-35 (Unit 2), D-43 and D-45 (Unit 3), M-49 (Unit 3), and provided to L-47 (Unit 3) will be modified by adding a brace or the Staff reinforcement to each column. These modifications are upon necessary to prevent potential failure of the column(s), issuance of when subjected to a pipe whip load. the SER.

45H Weep holes will be installed in the bottom of the Unit 3 Y outside-containment junction box enclosures for the Viking Electrical Penetrations. Also, the electrical penetration inspection procedure is being amended to inspect the weep holes for blockage.