ML20195K051
| ML20195K051 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 05/26/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20195K049 | List: |
| References | |
| PROC-880526, NUDOCS 8806290331 | |
| Download: ML20195K051 (11) | |
Text
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4 OYSTER CREEK 12R OUTAGE i
IGSCC INSPECTION / STRESS IMPROVEMENT PLANS l
GPU NUCLEAR CORP.
MAY 26,1988 l
1 G806270331 880616 PDR hDOCK 0500021t)
O purg
OUTLINE 3
OYSTER CREEK IGSCC EXPERIENCE l
12R OUTAGE INSPECTION AND STRESS IMPROVEMENT PLANS BASIS FOR INSPECTION PLAN PERCENTAGES TECHNICAL BASIS FOR INSPECTING (100% OF STRESS IMPROVED WELDS GENERAL ALARA TECHNICAL COMPARISON OF GPUN PLAN AND 84-11 REINSDECTIONS NEW INSPECTIONS POST-STRESS IMPROVEMENT INSPECTIONS
SUMMARY
AND CONCLUSIONS i
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BACKCROUND/ HISTORY OF WELDS IN 84-11 SCOPE NO ICSCC DETECTED PI 10R REINSP PI TOTAL 10R IN llR TOTAL ICSCC DETECTED, ICSCC DETECTED, SYSTEM WELDS NI*
ONLY IIR ONLY INSP NOT REPLACED REPLACED RECIRC.
89 20(5) 2 28 36 66 3 - 2 OL, 1 SI O
SHUTDOWN COOLING 14 8(0) 0 2
4 6
0 0
CORE SPRAY 26 18(0) 0 1
7 8
0 0
RWCU 51 35(5) 6 2
8 16 0
0 ISO CONDENSER l
INSIDE 2ND VALVE 58 34(14) 12 6
6 24 0
0 i
OUTSIDE 2?JD VALVE 131 19(2) 54 39 0
93 19 - All OL 9 w/ IGSCC. 17 new welds in 10R I
CLOSURE HEAD 8
8(0) 0 0
0 0
0 TOTAL 377 142(26) 74 78 61 213 22 o UNINSPECTABLE WELDS IN "( )"
a GPUN 12R IGSCC INSPECTION PLAN TOTAL BUTT PREV.
(GSCC SYSTEM WELDS WELDS INSP.
WELDS RECIRC 89 10 7
3 SHUTDOWN COOLING 14 3
0 0
CORE SPRAY 26 9
0 0
RWCU 51 10 0
0 ISC CONDENSER INSIDE 58 14 3
0 OUTSIDE 1 31 15 11 4
CLOSURE HEAD 8
2 0
0 TOTAL 377 63 17 7
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12R SI PLAN 2 DECIRC SAFE ENDS (4 WELDS) 2 CORE SPRAY SAFE ENDS (4 WELDS) 2 ISO. CONDENSER SAFE ENDS (4 WELDS) 22 CORE SPR AY PIPE WELDS (8" NPS) 9 ISO CONDENSER PlPE WELDS INSIDE DRYWELL (10" NPS)
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j BASIS FOR GPUN's 12R PLAN FOCUS ON WELDS NOT INSPECTED IN 10R (TO 82-03) OR 11R (TO 84-1 1)
PERCENTAGES ARE A COMBINATION OF 84-11 AND DRAFT REV. 2 OF NUREG 0313 1
STRESS IMPROVED IN 11R (RECIRC-61, ALL POST-Si INSPECTED): 10% (50% EVERY 10 YRS.)
INCLUDES WELDS REQUIRING ADDITION AL EXAMS TO DISPOSITION.
REMAINDER OF SYSTEMS INSIDE 2nd VALVE: 20%, MOSTLY UNINSPECTED IN 10R OR 11R ISO CONDENSER OUTSIDE 2nd VALVE: 10% (ALL INSPECTABLE WELDS INSPECTED IN 10R,17 NEW WELDS INSTALLED IN 10R)
IGSCC FOUND IN 11R: FOUR WELDS (100%,3 IN REClRC.,1 IN IC OUTSIDE ?.ND VALVE; 2 WERE INSPECTED IN 10R, DISPOSITIONED AS GEOMETRY) 3 M OF THE OL's DEPOSITED IN 10R (IC): 10%
ALL SAFE END WELDS (12) INSPECTED AFTER SI ALL NOT PREVIOUSLY INSPECTED DUE TO AS-WELDED CLADDING ON OD, SAMPLE EXPANSIONS, SHOULD IGSCC BE FOUND, IN ACCORD ANCE WITH 84-11 4
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BASIS FOR GPUN's 12R PLAN (cont'd) 84-11 REQUIRED REINSPECTION OF WELDS INSPECTED TO 82-03 84-11 INSPECTIONS PERFORMED UNDER PERSONNEL REQU ALIFICATION PROGRAM VERIFIED ADEQUACY OF 82-03 INSPECTIONS HWC TO BE IMPLEMENTED START OF CYCLE 12 NWC CONDUCTIVITY SINCE 82-03 INSPECTIONS EXCELLENT AVER AGE 4 0.11 pS/cm., FEW UPSETS CRACK GROWTH VERY SLOW UNDER THESE CONDITIONS DR AFT REV. 2 OF NUREG-0313 DOES NOT REQUIRE SUCCESSIVE-OUTAGE INSPECTION OF CATEGORY D WELDS i
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t INSPECTION AFTER STRESS IMPROVEMENT PLAN 2 RECIRC SAFE ENDS (4 WELDS)- INSPECT AFTER SI-2 CORE SPRAY SAFE ENDS (4 WELDS)-INSPECT AFTER Si 2 ISO. CONDENSER SAFE ENDS (4 WELDS)-INSPECT AFTER Si 22 CORE SPRAY PlPE WELDS (6" NPS) INSPECT 5, AIM TO PERFORM AFTER SI 9 ISO CONDENSER PIPE WELDS (10" NPS)- INSPECT 5, AIM TO PERFORM AFTER Si BASIS FOR INSPECTING < 100% OF SI'd WELDS GENERAL PHILOSOPHY - BETTER TO SI AND INSPECT < 100% THAN NOT PERFORM St.
ALARA - WELD CROWN REDUCTION AND INSPECTION HAVE BIG IMPACT ON DOSE (~ 18 MAN-REM FOR CURRENT PIPE SI SCOPE)
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BASIS FOR INSPECTING < 100% OF SI'd WELDS TECHNICAL GROWTH OF EXISTING CRACKS IN PIPE <12" NPS l
AS-WELDED: SHALLOW CR ACKS COULD GROW TO UNACCEPTABLE DEPTH IN < 1 CYCLE.
AS SI'd: CRACK MUST BE DEEP (> 50% TW) TO GROW i
(BY ANALYSIS)
GPUN UNAWARE OF GROWTH OF CRACKS IN SI'd WELDS i
GPUN UNAWARE OF NEW CRACKING IN SI'd WELDS WITH NO j
INDICATlOM3 IN PREVIOUS INSPECTIONS
}
F-REYlOUS FINDINGS OF "NEW" CR ACKS IN Sl'd WELDS ATTRIBUTED TO MISlNTERPRETATION OF PREVIOUS i
INSPECTION DATA.
i GPUN INSPECTION PLANS INCLUDE REINSPECTION OF WELDS WITH INDICATIONS CONSIDERED POTENTIAL, BUT ONLY SLlGHTLY SO, "MIS-CALLS" i
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GPUN PLAN AND 84-11 DIFFERENCES THESE ARE DIFFERENCES BETWEEN OUR APPROACH TO APPLYING 84-11 TO A SECOND OUTAGE VS. LITERAL INTERPRETATION OF l
DOCUMENT INTENDED TO APPLY TO ONE OUTAGE.
REINSPECTIONS 84-11 REQUIRES 20%, NLT 2 GPUN: 10% of RECIRC (SI'd),10% ISO CONDENSER OUTSIDE DRYWELL (ALL INSPECTED IN 10R)
NEW INSPEC1!ONS 84-11 REQUIRES 20% OF THOSE WELDS NOT PREVIOUSLY INSPECTED, NLT 4 GPUN: 20% OF TOTAL SYSTEM WELDS, NOT PREVIOUSLY INSPECTED POST-El INSPECTIONS 84-11 IMPLIES 100%
GPUN: 47% IN 12R (20 OF 43), BUT 88% (38 OF 43) WILL HAVE BEEN INSPECTED IN 10,11, AND 12R RECIRC: 4 OF 4 TO BE INSPECTED IN 12R CORE SPRAY 9 OF 26 TO BE INSPECTED IN 12R 8 OF 26 WERE INSPECTED IN 11R (2 WERE REPEATS OF 10R INSPECTION) 9 NOT INSPECTED FOR IGSCC ISO CONDENSER INSIDE DRYWELL 9 OF 13 TO BE INSPECTED IN 12R 4 OF 13 WERE INSPECTED IN 11R (2 WERE REPEATS OF 10R INSPECTION) 4531H
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SUMMARY
AND CONCLUSIONS l
PLAN TO INSPECT AT LEAST 20% OF WELDS NOT PREVIOUSLY INSPECTED IN 10R OR 11R.
REINSPECTION OF 10% OF WELDS PREVIOUSLY INSPECTED OCCURS IN SYSTEMS WHERE ALL WELDS HAVE RECEIVED AT i
LEAST ONE INSPECTION IN 10R AND/OR 11R.
l RECIRC AND ISO CONDENSER OUTSIDE DRYWELL GPUN SATISFIED WITH ADEQUACY OF 82-03 INSPECTIONS GOOD WATER CHEMISTRY IN CYCLES 10 AND 11 SIGNIFICANTLY REDUCES POTENTIAL FOR NEW CRACKS AND GROWTH RATE OF EXISTING CR ACKS INSPECTION OF <100% OF WELDS AFTER Si JUSTIFIABLE FOR SMALL DIAMETER PIPING j
INSPECTION PLAN ADEQUATE TO DETERMINE IF MAJOR IGSCC PROBLEM EXISTS AT OYSTER CREEK l
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MEETING
SUMMARY
DISTRIBUTION g
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iDocketFiIel NRC PDR PDI4 Gray File S. Varga B.Boger J. Stolz A.Drorrerick OGC E. Jordan B. Grirres ACRS (10)
GPA/PA HBClayton NRC Participants A.Dromerick W.H. Koo
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