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=Text=
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{{#Wiki_filter:June 26, 2012 Mr. Peter Dietrich Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674
{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION REGION I V 1600 EAST LAMAR BLVD ARLINGTON, TEXAS 76011-4511 June 26, 2012 Mr. Peter Dietrich Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128
-0128  


==SUBJECT:==
==SUBJECT:==
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==SUMMARY==
==SUMMARY==
FOR AUGMENTED INSPECTION TEAM EXIT MEETING WITH SOUTHERN CALIFORNIA EDISON COMPANY Dear Mr. Dietrich
FOR AUGMENTED INSPECTION TEAM EXIT MEETING WITH SOUTHERN CALIFORNIA EDISON COMPANY
:
 
==Dear Mr. Dietrich:==
 
On June 18, 2012, NRC personnel met with representatives of Southern California Edison at the San Juan Capistrano Community Center Community Hall, located in San Juan Capistrano, California to present the Augmented Inspection Team exit issues and observations.
On June 18, 2012, NRC personnel met with representatives of Southern California Edison at the San Juan Capistrano Community Center Community Hall, located in San Juan Capistrano, California to present the Augmented Inspection Team exit issues and observations.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading
In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
-rm/adams.html (the Public Electronic Reading Room).
Sincerely,
Sincerely,   /RA/
                                              /RA/
Gregory Werner, Chief       Plant Support Branch 2 Division of Reactor Safety
Gregory Werner, Chief Plant Support Branch 2 Division of Reactor Safety Docket Nos. 0500050361, 0500050362 License Nos. NPF-10, NPF-15
 
Docket Nos. 0500050361, 0500050362 License Nos. NPF
-10, NPF-15  


==Enclosure:==
==Enclosure:==
: 1. NRC Presentation
: 1. NRC Presentation
: 2. Southern California Edison Presentation     Electronic Distribution for SONGS U N I T E D S T A T E S N U C L E A R R E G U L A T O R Y C O M M I S S I O N R E G I O N I V1600 EAST LAMAR BLVD A R L I N G T O N , T E X A S 7 6 0 1 1-4511 
: 2. Southern California Edison Presentation Electronic Distribution for SONGS
 
ML12179A447 SUNSI Rev Compl. Yes  No            ADAMS      Yes  No    Reviewer Initials  GEW Publicly Avail            Yes  No    Sensitive  Yes  No    Sens. Type Initials  GEW C:PSB2                  PAO              RSLO                          C:PSB2 GEWerner                VLDricks          WAMaier                        GEWerner
/RA/                    /RA/              /E/                            /RA/
6/20/2012              6/21/12            6/26/12                        6/26/2012
 
NRC PRESENTATION San Onofre Nuclear Generating Station Augmented Inspection Team Purpose of Todays Meeting Public Exit Meeting Present the Status of the Augmented Inspection Discuss Activities Going Forward Answer Questions from the Audience Nuclear Regulatory Commission - Region IV June 18, 2012 1                                                        2 Agenda                                                NRC Representatives Introduction Augmented Inspection Team Decision                                Elmo Collins, Regional Administrator, Region IV Augmented Inspection Team Charter Thomas Blount, Acting Director, Division Reactor NRC Discussion on Augmented Inspection Status                      Safety Licensee Response to AIT Status Path Forward                                                      Greg Werner, Branch Chief , AIT Team Lead NRC Closing Remarks                                              Greg Warnick, Senior Resident Inspector Question and Answer Session 3                                                        4 NRC Representatives (Cont)                                            SONGS Representatives Michele Evans, Director, Division of Operating Reactor Licensing Peter Dietrich, Senior Vice President and Chief Ryan Lantz, Branch Chief, Region IV Nuclear Officer, SONGS, SCE Victor Dricks, Senior Public Affairs Officer, Region IV John Reynoso, Resident Inspector, AIT Team Member                  Douglas Bauder, Vice President and Station Manager, Emmett Murphy, Senior Materials Engineer, Office of Nuclear        SONGS, SCE Reactor Regulation, AIT Team Member Carl Thurston, Reactor Systems Engineer, Office of Research,      Thomas Palmisano, Vice President of Nuclear AIT Team Member Engineering, Projects and Site Support, SONGS, SCE Joel Rivera-Ortiz, Senior Reactor Inspector, Region II, AIT Team Member Michael Bloodgood, Operations Engineer, Region IV 5                                                        6 Enclosure 1
 
NRC PRESENTATION NRC Opening Remarks                                      Steam Generator Tube Leak Actual tube leak was of minor safety significance.
Elmo Collins, Regional Administrator , Region IV Offsite radiation release was minimal.
Thomas Blount, Acting Director, Division of Reactor Safety                                                    The plant operators responded properly and minimized the release.
8 7
AIT Decision Management Directive 8.3
                                                                  -      Pre-Planning
                                                                  -      Criteria
                                                                  -      NRC Response 9                                                          10 AIT Charter                                      AIT Issues and Observations Team Members - 7 inspectors/engineers from 5 NRC offices Eight tubes failed pressure testing.
Key Objectives SONGS used multiple independent consultants and S/G manufacturers.
Additional information and observations provided by the resident inspectors 11                                                          12 Enclosure 1


SUNSI Rev Compl.
NRC PRESENTATION AIT Issues and Observations (cont)                                      AIT Follow-up Items Ten items identified for follow-up:
Yes  No ADAMS Yes  No Reviewer Initials GEW Publicly Avail Yes  No Sensitive  Yes  No Sens. Type Initials GEW C:PSB2 PAO RSLO  C:PSB2 GEWerner VLDricks WAMaier  GEWerner /RA/ /RA/ /E/  /RA/ 6/20/2012 6/21/12 6/26/12  6/26/2012 NRC PRESENTATION Enclosure 1 1San Onofre Nuclear Generating StationAugmented Inspection Team Public Exit MeetingNuclear Regulatory Commission
Mitsubishis thermal/hydraulic computer simulation          1. Post trip/transient procedure model did not accurately predict the behavior of the
-Region IVJune 18, 2012 2Purpose of Today's MeetingPresent the Status of the Augmented InspectionDiscuss Activities Going ForwardAnswer Questions from the Audience 3AgendaIntroduction Augmented Inspection Team DecisionAugmented Inspection Team CharterNRC Discussion on Augmented Inspection StatusLicensee Response to AIT StatusPath ForwardNRC Closing RemarksQuestion and Answer Session 4NRC RepresentativesElmo Collins, Regional Administrator, Region IVThomas Blount, Acting Director, Division Reactor Safety Greg Werner, Branch Chief , AIT Team LeadGreg Warnick, Senior Resident Inspector 5NRC Representatives (Cont)Michele Evans, Director, Division of Operating Reactor  LicensingRyan Lantz, Branch Chief, Region IVVictor Dricks, Senior Public Affairs Officer, Region IVJohn Reynoso, Resident Inspector, AIT Team MemberEmmett Murphy, Senior Materials Engineer, Office of Nuclear Reactor Regulation, AIT Team MemberCarl Thurston, Reactor Systems Engineer, Office of Research, AIT Team MemberJoel Rivera
: 2. Evaluation and disposition of numerous steam and water in the steam generators.
-Ortiz, Senior Reactor  Inspector, Region II, AIT Team MemberMichael Bloodgood, Operations Engineer, Region IV 6SONGS RepresentativesPeter Dietrich, Senior Vice President and Chief Nuclear Officer, SONGS, SCE Douglas Bauder, Vice President and Station Manager, SONGS, SCEThomas Palmisano, Vice President of Nuclear Engineering, Projects and Site Support, SONGS, SCE
Unit 3 loose parts monitor alarms
: 3. Retainer bar design not evaluated for Manufacturing differences between the steam                    vibration impacts generators contributed to the difference in tube
: 4. Evaluation of and control of Unit 3 divider plate degradation.
repair
: 5. Unit 3 steam generator shipping requirements 13                                                            14 AIT Follow-up Items (cont)                                             AIT Summary
* The NRC understands the steam generator thermal
: 6. Lack of tube bundle support for steam                        hydraulic conditions that resulted in the tube generators during shipment                                  degradation.
: 7. Evaluation and disposition of shipping accelerometer data
* The thermal hydraulic conditions were not accurately predicted during design.
: 8. 50.59 evaluation
: 9. Control of manufacturing differences
* Additional actions to fix and prevent any additional tube-to-tube degradation due to excessive vibration
: 10. Adequacy of Mitsubishis computer simulation                are being evaluated and developed. The NRC has model                                                      additional inspections to perform.
* The NRC will take as much time as needed to 15        ensure the safety of the public.                  16 Path Forward - Key NRC Activities SONGS Response
* Continue review of steam generator tube wear
* Confirmatory Action Letter inspections Peter Dietrich
* Augmented Inspection followup inspection Senior Vice President
* Additional public meetings and
* NRC decision about the acceptability of the resumption of power operations Chief Nuclear Officer
* Routine process to recommend improvements to the inspection program 17                                                            18 Enclosure 1


NRC PRESENTATION Enclosure 1 7NRC Opening RemarksElmo Collins, Regional Administrator , Region IVThomas Blount, Acting Director, Division of Reactor Safety 8Steam Generator Tube LeakActual tube leak was of minor safety significance.Offsite radiation release was minimal.The plant operators responded properly and minimized the release.
NRC PRESENTATION NRC Closing Remarks Elmo Collins 15 Minute Break Regional Administrator Region IV 19                                                          20 Contacting the NRC
9 10AIT DecisionManagement Directive 8.3
* Report an emergency (301) 816-5100 (24/7 NRC Headquarters Operation Center) (call collect)
-Pre-Planning-Criteria-NRC Response 11AIT CharterTeam Members
* Report a safety concern:
-7 inspectors/engineers from 5 NRC officesKey Objectives Additional information and observations provided by the resident inspectors 12AIT Issues and ObservationsEight tubes failed pressure testing.SONGS used multiple independent consultants and S/G manufacturers.  
Questions and Answers                      (800) 695-7403 (Toll-free Safety Hotline)
Allegation@nrc.gov
* General information or questions www.nrc.gov
* Victor Dricks, Public Affairs Officer, RIV 817-200-1128 Victor.Dricks@nrc.gov 21                                                          22 Enclosure 1


NRC PRESENTATION Enclosure 1 13AIT Issues and Observations (cont)Mitsubishi's thermal/hydraulic computer simulation model did not accurately predict the behavior of the steam and water in the steam generators. Manufacturing differences  between the steam generators contributed to the difference in tube degradation.
SOUTHERN CALIFORNIA EDISON PRESENTATION SONGS EXCELLENCE 2012                                      SONGS EXCELLENCE 2012 Southern California Edison Commitment We operate San Onofre Nuclear Generating Station (SONGS) safely and reliably to the highest standards to protect the health and safety of the public and our employees Steam Generator Recovery Update                          We will not restart either Unit 2 or Unit 3 until we Nuclear Safety in Action                            and the NRC are satisfied it is safe to do June 18, 2012 SONGS EXCELLENCE 2012                                        SONGS EXCELLENCE 2012 Pressurized Water Reactor Layout Current Status
14AIT Follow
* Unit 2 Status:
-up ItemsTen items identified for follow
  - Shutdown on Jan. 9 for routine refueling and maintenance outage &
-up: 1.Post trip/transient procedure 2.Evaluation and disposition of numerous Unit 3 loose parts monitor alarms 3.Retainer bar design not evaluated for vibration impacts 4.Evaluation of and control of Unit 3 divider   plate repair 5.Unit 3 steam generator shipping requirements 15AIT Follow
reactor vessel head replacement
-up Items (cont) 6.Lack of tube bundle support for steam  generators during shipment 7.Evaluation and disposition of shipping accelerometer data 8.50.59 evaluation 9.Control of manufacturing differences 10.Adequacy of Mitsubishi's computer simulation  model 16AIT SummaryThe NRC understands the steam generator thermal hydraulic conditions that resulted in the tube degradation.The thermal hydraulic conditions were not accurately predicted  during design. Additional actions to fix and prevent any additional tube-to-tube degradation due to excessive vibration are being evaluated and developed. The NRC has additional inspections to perform.The NRC will take as much time as needed to ensure the safety of the public.
* Unit 3 Status:
17SONGS ResponsePeter DietrichSenior Vice President and Chief Nuclear Officer 18Path Forward
   - Operators safely shutdown Unit 3 after steam generator tube leak identified on January 31
-Key NRC ActivitiesContinue review of steam generator tube wearConfirmatory Action Letter inspections Augmented Inspection followupinspectionAdditional public meetingsNRC decision about the acceptability of the resumption of power operationsRoutine process to recommend improvements to the inspection program
  - Shared learning with industry 3                                                            4 SONGS EXCELLENCE 2012                                        SONGS EXCELLENCE 2012 Steam Generator Cut-Away Elevation View Actions Taken to Date
* Discovered unexpected tube-to-tube wear in limited portions of Unit 3 steam generators
* Deferred Unit 2 restart pending investigation
* Assembled team of experts to inform, assist and challenge
* Completed extensive tests and analysis on both units in all steam generators to support determining cause 5                                                            6 Enclosure 2


NRC PRESENTATION Enclosure 1 19NRC Closing RemarksElmo CollinsRegional AdministratorRegion IV 15 Minute Break 20 21Questions and Answers Contacting the NRCReport an emergency(301) 816-5100 (24/7 NRC Headquarter'sOperation Center)    (call collect)Report a safety concern
SOUTHERN CALIFORNIA EDISON PRESENTATION SONGS EXCELLENCE 2012                                         SONGS EXCELLENCE 2012 Technical Expertise Supporting SCE Cause of Unexpected Tube-to-Tube Wear
:  (800) 695-7403 (Toll
* Mitsubishi Heavy
-free Safety Hotline) Allegation@nrc.govGeneral information or questionswww.nrc.govVictor Dricks, Public Affairs Officer, RIV817-200-1128Victor.Dricks@nrc.gov 22 SOUTHERN CALIFORNIA EDISON PRESENTATION Enclosure 2 SONGS EXCELLENCE 2012Steam Generator Recovery UpdateNuclear Safety in ActionJune 18, 2012 SONGS EXCELLENCE 2012We operate San Onofre Nuclear Generating Station (SONGS) safely and reliably to the highest standards to protect the health and safety of the public and our employeesWe will not restart either Unit 2 or Unit 3 until we and the NRC are satisfied it is safe to doSouthern California Edison Commitment SONGS EXCELLENCE 2012Current StatusUnit 2 Status:
* AREVA Industries
-Shutdown on Jan. 9 for routine refueling and maintenance outage & reactor vessel head replacementUnit 3 Status:
* Specific mechanism is Fluid Elastic Instability causing excessive tube vibration
-Operators safely shutdown Unit 3 after steam generator tube leak identified on January 31
* Westinghouse
-Shared learning with industry 3 SONGS EXCELLENCE 2012 4Pressurized Water Reactor Layout SONGS EXCELLENCE 2012Steam Generator Cut
* B&W Canada                      - Most excessive wear occurring in limited area of Unit 3 steam generators
-Away Elevation View 5 SONGS EXCELLENCE 2012Actions Taken to DateDiscovered unexpected tube
* This is due to:
-to-tube wear in limited portions of Unit 3 steam generatorsDeferred Unit 2 restart pending investigationAssembled team of experts to inform, assist and challengeCompleted extensive tests and analysis on both units in all steam generators to support determining cause 6
* High steam flow velocities
SOUTHERN CALIFORNIA EDISON PRESENTATION Enclosure 2 SONGS EXCELLENCE 2012Technical Expertise Supporting SCEMitsubishi Heavy IndustriesWestinghouseMPR AssociatesAREVA                        B&W CanadaEPRI 7Other industry personnel, recognized academics and specialized consultants SONGS EXCELLENCE 2012Cause of Unexpected Tube
* MPR Associates
-to-Tube WearSpecific mechanism is Fluid Elastic Instability causing excessive tube vibration  
* EPRI
-Most excessive wear occurring in limited area of Unit 3 steam generators This is due to: High steam flow velocities Very dry steamInadequate tube support structure in the U bend region for the tubes experiencing the wear 8 SONGS EXCELLENCE 2012Next StepsFollow up on Augmented Inspection Team's additional requestsImplement our corrective actionsDevelop additional information as stated in Confirmatory Action Letter Continue work to develop intermediate and long term solutions
* Very dry steam
-Will require extensive analysis, mock
* Inadequate tube support structure in the U bend region for the tubes experiencing the wear
-ups and testing 9 SONGS EXCELLENCE 2012 10There is no timeline on safety}}
* Other industry personnel, recognized academics and specialized consultants 7                                                              8 SONGS EXCELLENCE 2012                                        SONGS EXCELLENCE 2012 Next Steps
* Follow up on Augmented Inspection Teams additional requests
* Implement our corrective actions
* Develop additional information as stated in Confirmatory Action Letter
* Continue work to develop intermediate and long term solutions
  - Will require extensive analysis, mock-ups and testing There is no timeline on safety 9                                                            10 Enclosure 2}}

Latest revision as of 02:31, 12 November 2019

6/18/2012 Meeting Summary for Augmented Inspection Team Exit Meeting with Southern California Edison Co
ML12179A447
Person / Time
Site: San Onofre  Southern California Edison icon.png
Issue date: 06/26/2012
From: Greg Werner
NRC/RGN-IV/DRS/PSB-2
To: Peter Dietrich
Southern California Edison Co
vlm/Werner G
References
Download: ML12179A447 (8)
v • d • e


Text

UNITED STATES NUCLEAR REGULATORY COMMISSION REGION I V 1600 EAST LAMAR BLVD ARLINGTON, TEXAS 76011-4511 June 26, 2012 Mr. Peter Dietrich Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128

SUBJECT:

MEETING

SUMMARY

FOR AUGMENTED INSPECTION TEAM EXIT MEETING WITH SOUTHERN CALIFORNIA EDISON COMPANY

Dear Mr. Dietrich:

On June 18, 2012, NRC personnel met with representatives of Southern California Edison at the San Juan Capistrano Community Center Community Hall, located in San Juan Capistrano, California to present the Augmented Inspection Team exit issues and observations.

In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,

/RA/

Gregory Werner, Chief Plant Support Branch 2 Division of Reactor Safety Docket Nos. 0500050361, 0500050362 License Nos. NPF-10, NPF-15

Enclosure:

1. NRC Presentation
2. Southern California Edison Presentation Electronic Distribution for SONGS

ML12179A447 SUNSI Rev Compl. Yes No ADAMS Yes No Reviewer Initials GEW Publicly Avail Yes No Sensitive Yes No Sens. Type Initials GEW C:PSB2 PAO RSLO C:PSB2 GEWerner VLDricks WAMaier GEWerner

/RA/ /RA/ /E/ /RA/

6/20/2012 6/21/12 6/26/12 6/26/2012

NRC PRESENTATION San Onofre Nuclear Generating Station Augmented Inspection Team Purpose of Todays Meeting Public Exit Meeting Present the Status of the Augmented Inspection Discuss Activities Going Forward Answer Questions from the Audience Nuclear Regulatory Commission - Region IV June 18, 2012 1 2 Agenda NRC Representatives Introduction Augmented Inspection Team Decision Elmo Collins, Regional Administrator, Region IV Augmented Inspection Team Charter Thomas Blount, Acting Director, Division Reactor NRC Discussion on Augmented Inspection Status Safety Licensee Response to AIT Status Path Forward Greg Werner, Branch Chief , AIT Team Lead NRC Closing Remarks Greg Warnick, Senior Resident Inspector Question and Answer Session 3 4 NRC Representatives (Cont) SONGS Representatives Michele Evans, Director, Division of Operating Reactor Licensing Peter Dietrich, Senior Vice President and Chief Ryan Lantz, Branch Chief, Region IV Nuclear Officer, SONGS, SCE Victor Dricks, Senior Public Affairs Officer, Region IV John Reynoso, Resident Inspector, AIT Team Member Douglas Bauder, Vice President and Station Manager, Emmett Murphy, Senior Materials Engineer, Office of Nuclear SONGS, SCE Reactor Regulation, AIT Team Member Carl Thurston, Reactor Systems Engineer, Office of Research, Thomas Palmisano, Vice President of Nuclear AIT Team Member Engineering, Projects and Site Support, SONGS, SCE Joel Rivera-Ortiz, Senior Reactor Inspector, Region II, AIT Team Member Michael Bloodgood, Operations Engineer, Region IV 5 6 Enclosure 1

NRC PRESENTATION NRC Opening Remarks Steam Generator Tube Leak Actual tube leak was of minor safety significance.

Elmo Collins, Regional Administrator , Region IV Offsite radiation release was minimal.

Thomas Blount, Acting Director, Division of Reactor Safety The plant operators responded properly and minimized the release.

8 7

AIT Decision Management Directive 8.3

- Pre-Planning

- Criteria

- NRC Response 9 10 AIT Charter AIT Issues and Observations Team Members - 7 inspectors/engineers from 5 NRC offices Eight tubes failed pressure testing.

Key Objectives SONGS used multiple independent consultants and S/G manufacturers.

Additional information and observations provided by the resident inspectors 11 12 Enclosure 1

NRC PRESENTATION AIT Issues and Observations (cont) AIT Follow-up Items Ten items identified for follow-up:

Mitsubishis thermal/hydraulic computer simulation 1. Post trip/transient procedure model did not accurately predict the behavior of the

2. Evaluation and disposition of numerous steam and water in the steam generators.

Unit 3 loose parts monitor alarms

3. Retainer bar design not evaluated for Manufacturing differences between the steam vibration impacts generators contributed to the difference in tube
4. Evaluation of and control of Unit 3 divider plate degradation.

repair

5. Unit 3 steam generator shipping requirements 13 14 AIT Follow-up Items (cont) AIT Summary
6. Lack of tube bundle support for steam hydraulic conditions that resulted in the tube generators during shipment degradation.
7. Evaluation and disposition of shipping accelerometer data
  • The thermal hydraulic conditions were not accurately predicted during design.
8. 50.59 evaluation
9. Control of manufacturing differences
  • Additional actions to fix and prevent any additional tube-to-tube degradation due to excessive vibration
10. Adequacy of Mitsubishis computer simulation are being evaluated and developed. The NRC has model additional inspections to perform.
  • The NRC will take as much time as needed to 15 ensure the safety of the public. 16 Path Forward - Key NRC Activities SONGS Response
  • Augmented Inspection followup inspection Senior Vice President
  • Additional public meetings and
  • NRC decision about the acceptability of the resumption of power operations Chief Nuclear Officer
  • Routine process to recommend improvements to the inspection program 17 18 Enclosure 1

NRC PRESENTATION NRC Closing Remarks Elmo Collins 15 Minute Break Regional Administrator Region IV 19 20 Contacting the NRC

  • Report an emergency (301) 816-5100 (24/7 NRC Headquarters Operation Center) (call collect)
  • Report a safety concern:

Questions and Answers (800) 695-7403 (Toll-free Safety Hotline)

Allegation@nrc.gov

  • General information or questions www.nrc.gov
  • Victor Dricks, Public Affairs Officer, RIV 817-200-1128 Victor.Dricks@nrc.gov 21 22 Enclosure 1

SOUTHERN CALIFORNIA EDISON PRESENTATION SONGS EXCELLENCE 2012 SONGS EXCELLENCE 2012 Southern California Edison Commitment We operate San Onofre Nuclear Generating Station (SONGS) safely and reliably to the highest standards to protect the health and safety of the public and our employees Steam Generator Recovery Update We will not restart either Unit 2 or Unit 3 until we Nuclear Safety in Action and the NRC are satisfied it is safe to do June 18, 2012 SONGS EXCELLENCE 2012 SONGS EXCELLENCE 2012 Pressurized Water Reactor Layout Current Status

  • Unit 2 Status:

- Shutdown on Jan. 9 for routine refueling and maintenance outage &

reactor vessel head replacement

  • Unit 3 Status:

- Operators safely shutdown Unit 3 after steam generator tube leak identified on January 31

- Shared learning with industry 3 4 SONGS EXCELLENCE 2012 SONGS EXCELLENCE 2012 Steam Generator Cut-Away Elevation View Actions Taken to Date

  • Discovered unexpected tube-to-tube wear in limited portions of Unit 3 steam generators
  • Deferred Unit 2 restart pending investigation
  • Assembled team of experts to inform, assist and challenge
  • Completed extensive tests and analysis on both units in all steam generators to support determining cause 5 6 Enclosure 2

SOUTHERN CALIFORNIA EDISON PRESENTATION SONGS EXCELLENCE 2012 SONGS EXCELLENCE 2012 Technical Expertise Supporting SCE Cause of Unexpected Tube-to-Tube Wear

  • Mitsubishi Heavy
  • AREVA Industries
  • Specific mechanism is Fluid Elastic Instability causing excessive tube vibration
  • Westinghouse
  • This is due to:
  • High steam flow velocities
  • Very dry steam
  • Inadequate tube support structure in the U bend region for the tubes experiencing the wear
  • Other industry personnel, recognized academics and specialized consultants 7 8 SONGS EXCELLENCE 2012 SONGS EXCELLENCE 2012 Next Steps
  • Follow up on Augmented Inspection Teams additional requests
  • Implement our corrective actions
  • Develop additional information as stated in Confirmatory Action Letter
  • Continue work to develop intermediate and long term solutions

- Will require extensive analysis, mock-ups and testing There is no timeline on safety 9 10 Enclosure 2

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