ML18059A423
ML18059A423 | |
Person / Time | |
---|---|
Site: | Palisades ![]() |
Issue date: | 10/07/1993 |
From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
To: | |
Shared Package | |
ML18059A421 | List: |
References | |
PROC-931007, NUDOCS 9310120434 | |
Download: ML18059A423 (14) | |
Text
9310120434 931007 PDR ADOCK05000255 5 .. PDR ENCLOSURE 2 Consumers Power Company Palisades Plant Docket 50-255 PRESSURIZER SAFE END CRACK ACTION PLAN October 7, 1993
- PALISADES PLANT PRESSURIZER SAFE END CRACK REPAIR ACTION PLAN REVISION 0 10/07 /93 APPROVALS:
Action Plan Revision 0: Plant General Manager Date PURPOSE: The purpose of the Pressurizer Safe End Crack Repair Action Plan is to provide a document which identifies responsibilities, ensures necessary actions are completed prior to the plant startup, and ensures assignments for long term actions are made. The Action Plan may only be modified with the approval of the Plant General Manager or his designated alternate .
- Page 1 of 5 Action Plan 1. Conduct an engineering evaluation of the failure. The specific elements of this engineering analysis include the following:
- a. Metallurgical analysis of the failed safe end to identify the cause of the crack. Metallurgical Analysis Complete and Crack Cause Evaluated NECO Mechanical, Civil, and Structural Manager b. Analysis of factors contributing to PWSCC in the pressurizer nozzle safe end. This includes evaluation of material properties and stresses that may have contributed to the failure. Piping stresses and weld residual stresses are being evaluated and will be reviewed by an independent third party . Analysis of Material Properties and Stresses Complete and Third Party Review Complete NECO Mechanical, Civil, and Structural Manager c. Evaluation of other nozzles safe ends in the primary coolant system, based on the engineering evaluation of the failure, to identify other locations which may be susceptible to the same failure cause. This evaluation includes both nozzles with Inconel 600 safe ends and other safe end materials.
Contributing factors to PWSCC will also be evaluated for the safe ends that are identified as being susceptible to the same failure cause. This will include evaluation of material properties and stresses.
Nozzle Safe End Evaluation Complete NECO Mechanical, Civil, and Structural Manager
- Page 2 of 5 d. Evaluation of appropriate non-destructive examination techniques to identify similar flaws in other susceptible safe ends. Evaluation of NDE Predictive Testing Services Supervisor
- 2. Identify corrective actions for the specific safe end that failed. An engineering evaluation of the repair to the pressurizer safe end, based on the root cause analysis of the failure, has shown that. the lifetime of the repaired safe end well exceeds the length of the next operating cycle. Corrective Actions of Safe End Failure Identified NECO Mechanical, Civil, and Structural Manager 3. Identify corrective actions for other safe ends that may be susceptible to the same failure. Other safe ends that may be susceptible to the same failure will be inspected for flaws using appropriate non-destructive examination techniques.
NDE for Additional Safe Ends Identified, Documented, and Evaluated Satisfactorily Predictive Testing Services Supervisor
- Page 3 of 5 4. Complete necessary corrective actions to ensure safe operation of Palisades during the next operating cycle prior to returning the plant to service. a. Repair of the failed pressurizer safe end. Repair Complete Maintenance Manager b. Non-destructive examinations of other safe ends potentially susceptible to the same failure cause. Repair Complete and Acceptance NDE Satisfactory Predictive Testing Services Supervisor
- 5. Identify corrective actions necessary to ensure long term safe operation of Palisades.
- a. Engineering evaluation of additional repairs which may be necessary for long term operation of the pressurizer safe ends will be performed and additional repairs and corrective actions, if required, will be completed by the end of the next refueling shutdown.
Assign Action for the Above Corrective Actions for Next Refueling Outage NECO Mechanical, Civil, and Structural Manager
,-*
- Page 4of5 b. Further evaluation of non-destructive examination techniques in light of the pressurizer safe end crack will be conducted.
Enhanced ultrasonic techniques will be employed in an augmented inspection program for safe ends beginning in the next refueling shutdown.
To provide assurance that we are performing the most effective NDE possible the following actions will be completed:
Assign Action to Evaluate NDE Techniques and Employ Them in Augmented Inspection Program in Next Refueling Outage 6. Technical Report Prepared, Finalized.
- 7. Send Report to NRC. 8. Hold Meeting with NRC to Review Technical Report. Predictive Testing Services Supervisor NECO Mechanical, Civil and Structural Manager Safety and Licensing Manager Safety and Licensing Manager 9. Provide NRC with crack tip sample for independent sample analysis.
Predictive Testing Service Supervisor Page 5 of 5
- 10. PRC Review of Technical Report and Recommended Approvals.
PRC Chairman 11. Authorization For Leaving Cold Shutdown.
Plant General Manager
- I . I
' *
- ENCLOSURE 3 Consumers Power Company Palisades Plant Docket 50-255 PRESSURIZER SAFE END CRACK NDE
SUMMARY
October 7, 1993 WALL THICKNESS WELD # DIA PIEL SEIF N PORV #1 6" 1.5" 1.8" SE TO NOZZLE 4-6" .438" 1.5" WELD #lA SE TO PIPE I SPRAY #20 4" .625" .625" ELBOW TO SE #21 #21 NOZZLE 4-8" .625" 2. 5" TO SE RELIEF VALVES RV-1039 #1 6" 1.3" 1. 6" NOZZLE TO IN FLANGE RV-1040 #1 6" 1. 3" 1. 6" NOZZLE TO IN FLANGE RV-1041 #1 I 6" 1. 3" 1. 6" NOZZLE TO IN FLANGE Do = Scheduled But Not Complete Done = Completed
- No = Decision Made Not To Examine SURFACE PROFILE ID OD Smooth Moderate Bore Transition Taper Heavy Bore Transition As No Welded Transition Smooth Heavy Bore Transition Smooth Moderate Bore Transition Smooth Moderate Bore Transition Smooth Moderate Bore I Transition P/EL = Pipe or Elbow SE = Safe End N Nozzle F = Flange RT OD CIL PT Done Done Done Done Done Done Done Done Done Done Done Done Done Done ID IGSCC CODE PT UT UT COMMENTS Done No* No* *Configuration precludes UT Done No* No* . New Weld *Configuration precludes UT No No* No* *Configura-ti on precludes UT No No* No* *Configura-tion precludes UT Done Done No Done Done No Done Done ifo Effective as of October 7, 1993
- WALL THICKNESS WELD # DIA P/EL SEIF PORV PIPING WELDS WELD #2 4" .438 PIPE TO PIPE WELD #3 4" .438 PIPE TO ELBOW WELD #4 4" .438 ELBOW TO PIPE WELD #5 4" .438 PIPE TO ELBOW WELD #6 4" .438 ELBOW TO PIPE Do = Scheduled But Not Complete Done = Completed No = Decision Made Not To Examine N SURFACE PROFILE ID OD As-No Welded Transition As-No Welded Transition As-No Welded Transition As-No Welded Transition As-No Welded Transition P/EL = Pipe or Elbow SE = Safe End N Nozzle F Flange RT OD C/L PT Done Done Done Done Done Done Done Done Done Done -=* ID IGSCC CODE PT UT UT COMMENTS No No No New Weld No No No New Weld No No No No No No No No No Effective as of October 7, 1993 PRESSlJRl2ER VALVE OZZLE ASSEt16l Y IMCDMNEL FLANGE 1 1iELD '"1 r:
- j . I I ' r 1Jf1Ti'1 E( J. ---L I *,_ .,\
WELD *2 \.VELD # 1 A c z w w ...... <( (0 WELD # 1-------.....__
-LU _J N N 0 _z PORV NOZZLE ASSEMBLE SPRAY NOZZLE ASSEMBLE r WELD #6 October 8, 1993 THE ATTACHED TWO DOCUMENTS (ONE OF WHICH IS PROPRIETARY)
AR.E REFERENCES LISTED IN CONSUMERS 10/7 /93 LETTER FROM SLADE TO NRC DOCUMENT CONTROL DESK. THESE DOCUMENTS WERE SENT TO NRC AT NRC'S REQUEST AND
- SHOULD BE DOCKETED ALONG WITH THE INCOMING LETTER. THANK YOU. ,CAROLE JAMERSON, PD3-1 -,* *' : 504-1337'
*, .. , **: *.' . , -..: .:* ... :. *: ,,.,* ***.* ' . . ' . ,' ' ' *,, '.*. i
- OUTLINE
- PRESENT SITUATION
- CORRELATION ANALYSIS
- PRESSURIZER NOZZLES
- TUBE MATERIAL
- THEORETICAL MODEL
- WEIBULL FAILURE MODEL
- EST/MA TION OF PARAMETERS
- DEVELOPMENT OF EXTREMAL MODEL *ESTIMATION OF BOUNDS FOR FIRST FAILURES
- APPL/CATION TO CROM LIFE PREDICT/ON ANALYSIS
- CASE 1 : 50 KS/ MATERIAL
- CASE 2: 36 KS/ MATERIAL
- CONCLUSIONS I ALLOY600
- PRESENT SITUATION
- RECENT HISTORY *STATUS OF PRESSURIZER NOZZLES
- FIELD FAILURES EVEN IN LEAST SUSCEPTIBLE HEATS
- STATISTICAL QUANDRY
- ONLY INITIAL FAILURE INFORMATION AVAILABLE
- DIFFICULTY IN DEVELOPING OVERALL ASSESSMENT
- I ALLOY600