PY-CEI-NRR-1264, Summary Technical Rept,Evaluation of Indications in Perry Feedwater to Safe-End Welds

Summary Technical Rept,Evaluation of Indications in Perry Feedwater to Safe-End Welds

ML20062H047
Person / Time
Site:	Perry
Issue date:	11/21/1990
From:	Fleming W, Thornton H CLEVELAND ELECTRIC ILLUMINATING CO.
To:
Shared Package
ML20062H041	List: ML20062H040 PY-CEI-NRR-1264, Summary Technical Rept,Evaluation of Indications in Perry Feedwater to Safe-End Welds
References
PY-CEI-NRR-1264, NUDOCS 9012040060
Download: ML20062H047 (8)

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SUMMARY

TECHNICAL REPORT EVALUATION OF THE INDICATION (S)

IN THE PERRY FEEDWATER TO SAFE-END WELDS November 21, 1990 Cleveland Electric Illuminating Company l

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4 PY-CEI/NRR-1264 L g Attachment 2 As part of Perry's Inserw ;e Inspection (ISI) Program, all six reed-water (rW) nozzle to sa: and welds were ultrasonically examined (UT) during the second refuel outage (RFO-2). Flaws were detected in nozzles N4E and N4C that were outside of the acceptance criteria of IWB 3514.3 of ASME XI (reference Nonconformance Reports 490-S-270 and 90-S-277 dated November 9, 1990 and November 13, 1990, respectively).

Both flaws were 0.15" deep, with the flaw in nozzle N4C being 2.9" long, versus 1.6" long for nozzle N4E. Since both flaws are the same depth, and very nearly the same location (although one was oriented at 6:00 0' Clock and the other 012:00 o' clock - see Figure

1. 1), justification for the larger flaw will serve as *.e :hnical justification for both.

The UT indications were not identifiable as characterit. tic of IGSCC.

L However, the current limited size of the irdications maf de such

! that IGSCC charactettstics would not be sufficiently pronounced 3 be apparent. Consequently, CEI has taken a conservative appecach and included an appropriate IGSCC contribution in conjunction with cyclic fatigue growth when determining the " final" flaw size. The

'inal flaw size is fully acceptable within the criteria of ASME XI, Tables IWB 3641-5 and 3641-6 for the full duration af operating cycle 3 for Perry (nominal 18 month cycle).

l The subject nozzles will be UT re-inspected during 'efueling Outage 43 (RF1-3) and further engineering evaluation will be performed at that time. The current conservative projected results, however, l

indicate that some additional action (i.e., other than a "use-as-is" l condition) would be required beyond RFO-3. '

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PY-CEI/Niut-1264 L Attachant 2 STRESS HISTORY The stress hissory for this location was taken from CBIN Stress Report #4,(L4, T4, S4 and F4), as analyzed for the modified sparger configuration. (GE had changed the sparger attachment from being welded to a " freeze fit" configuration to remove a " cyclic" fatigue weld problem in the attachment weld). A residual stress .as added to the stress profile. The value of residual stress added was a function of percentage of crack depth (a/t). The equation used was i taken from NUROG-0313/ Revision 2 with a suggested value for Sy of 30 kai, which closely approximates the value for Inconel 182 of 28.4 ksi at temperature.

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PY-CEI/NRR-1264 L Attacha nt 2 CRACK GROWTH The initial crack of 0.15" deep X 2.9" long was projected to grow for 1148 operating cycles, assuming worst case cycle combination to determine " Delta" K 7 From Figure C-3210-1 of ASME XI, the projected cyclic fatigue growth increased the flaw depth to only 0.16". The growth attributed to the '.GSCC contribution for the 12000 operational hours during operating cycle 3 is 0.29 This is based on a crack gravth rate of 2.41 x 10-5 in/hr, which came from EPRI NP-5882M, Project 1566-1 " Stress Corrosion Cracking Resistance of Alloy 600 and 690 and Compatible Weld Metals in BWRs". (In conversations with personnel at River Bend, this value is comparable to what was used in their evaluation).

The reported crack g;owth rate is associated with a K y value of 46.0 MPafm (41.9 ksifIn). This compares favorably with the actual K y expected for normal operating conditions (26.9 ksifIn). Since the crack growth rate is a function of K g, the actual rate would be expected to be less than the value used, and the calculated growth is conservative. Concurrent with the crack growth to a depth of 0.45" is the circumferential growth to 9". This growth was based on the 20:1 (maximum) aspect ratio (or circumferential growth) as specified in NUREG-0313/ Revision 2. See Figure 2 for the projected crack growth for operating cycle 3. TP: contribution of emergency or faulted conditions on the crack growth produced a negligible effect (on the final projected crack depth).

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PY-CEI/NRR-1264 L Attachment 2 ACCEPTANCE CRITERIA Although the flaw location is at or close to the Inconel 182 butter-ing and the SA-508 Class 1 interface, it was assumed (as dictated by ASME XI) that the crack growth would occur in the buttering. The buttering was applied by using SMAW procedures; consequently rables IWB 3( '-5 and 3641-6 are the basis of the acceptance criteria.

Figure 2 shows the acceptance envelopes based on a stress ratio of 0.81. This value considers the Primary Membrane and Primary Bending contribution to be 13.0 kai as determined by CBIN in Repott D4, and an expansion stress (Pe) value of 16.0 ksi for RFE stress, based upon GE specified design thermal loads for the reedwater nozzle.

The acceptance criteria determines en allowable crack depth v.lue of 0.65", versus the projected (calculateci growth to 0.45". This difference of 0.20" supplies almost a 50% margin at the end of the next operational cycle for Perry.

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-d PY-CEI/NRR-1264 L Attachment 2 CONCLUSIONS l 1. The subject indications have been evaluated and shown to be l

acceptable as-is for continued full service operation during Perry's next operating cycle (Cycle #3).

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[ 2. Subsequent to UT inspection of the subject welds during RPO-3, an engineering evaluation will be performed to determine additional corrective actions (if any).

3. The subject nozzle welds will be treated as Category "r" weld-

! ments per Generic Letter 88-01/ Revision 0, Table 1 until such time as.further inspection / evaluation justifies otherwise.

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A = 2.9" N0ZZLE N40 A = 1.6" N0ZZLE N4E SECTION "A-A" a = 0.15" 8OTH N0ZZLES

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1. SAFE END 8 UTTERING

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2. FIELO WELD IN82 ROOT-PASS WITH INCONEL 82 HOT PASSESM AND INCONEL id2 FILL ,

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3. PORTION OF ORIGINAL FIELO WELD

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4. N0ZZLE BUTTERING

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5. ORIGINAL SAFE ENO INCONEL 600

• IN82 ANO IllCONEL 82 HAVE IDENTICAL 1 CHEMICAL COMPOSITION REQUIREMENTT AS SPECIFIED BY ASME SECTION II PART C SFA 5.30 +G SFA 5.14.RESPECTIVELY.

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