ML17311B235

Forwards Revised ARC Region Projections for PVNGS Unit 3 Refueling Outage 5,as Requested During 950920 Meeting W/Nrc

ML17311B235
Person / Time
Site:	Palo Verde
Issue date:	10/16/1995
From:	Stewart W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
102-03513-WLS-S, 102-3513-WLS-S, NUDOCS 9510250190
Download: ML17311B235 (14)

Text

PRIORITY 1 (ACCELERATED RZDS PROCESSING)

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9510250190 DOC.DATE: 95/10/16 NOTARIZED: NO DOCKET FACIL:STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 P AUTH. NAME AUTHOR AFFILIATION STEWART,W.L. Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Forwards revised ARC region projections for PVNGS Unit 3 Refueling Outage 5,as requested during 950920 meeting w/NRC.

DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR ENCL SIZE-TITLE: OR Submittal: General Distribution NOTES:Standardized plant. 05000530 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD4-2 LA 1 1 PD4-2 PD 1 1 THOMAS,C 1 1 INTERNAL: ACRS 6 6 FILE'ENTER~1 1 1 NRR/DE/EMCB 1 1 NRR/DRCH/HICB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 NUDOCS-ABSTRACT 1 1 OGC/HDS2 1 0

'EXTERNAL: NOAC 1 1 NRC PDR 1 1 D

N NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESKS ROOM OWFN 5D8 (415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 18 ENCL 17

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Arizona Public Service Company P.O. BOX 53999 ~ PHOENIX. ARIZONA 85072-3999 WILLIAML. STEWART 102-03513-WLS/SAB/RJR EXECUTIVEVICEPRESIOENT NUCLEAR October 16, 1995 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001

References:

(1) Unit 3 Steam Generator, Evaluation, May 1995, submitted to USNRC via letter 102-03364-WLS/SAB/JRP, dated May 19, 1995 (2) Unit 2 Steam Generator Evaluation, August 1995, submitted to USNRC via letter 102:03465-WLS/SAB/JRP, dated September 7, 1995

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 3 Docket No. STN 50-530 Unit 3 Refueling Outage 5 ARC Region Projections This letter is being sent as requested during the meeting between the NRC Staff and APS on September 20, 1995. During the meeting, APS indicated that the Unit 3 results presented on July 12, 1995 had not been adjusted for the use of the Plus Point Probe. The enclosure contains the revised projections for U3R5 and is provided in distributional form in Figures 1 and 2.

Figure 1 provides projections using the Unit 3 base case input which incorporates best estimate crack growth rates as described:in Reference 1. Figure 2 provides a similar projection using the upper bound 95%.crack growth rates also derived from Unit 3 specific data. In both cases, the basic Weibull crack initiation parameters were maintained per the Unit 3 base values. The basic Weibull:initiation function for Unit 3 has a shape parameter of 5.8 and a scale parameter of 22 EFPY. In each case, however, the setback parameter (as described in Reference 2) has been optimized on the basis of the U3R3, U3R4, and U3M5 actual results.

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U.h..lluclear Regulatory Commission ATTN: Document Control Desk Unit 3 Refueling Outage 5 ARC Region Projections Page 2 The crack projection numbers for Figures l and 2 are based on the Plus Point Probability of Detection function described in Reference 2. The POD function was applied exclusively to the simulated U3R5 inspection. An MRPC POD function was utilized for the earlier inspections. Figure 3 has been reprinted from Reference 2 and has been provided to show the predicted results of performing the U3R5 inspection with the standard MRPC.

Comparison of these figures show the relative impact of performing the U3R5 inspection using standard MRPC and Plus Point.

I Should you have any questions, please contact Scott A. Bauer at (602) 393-5978.

Sincerely, WLS/SAB/RJR/dpr-Enclosure cc: K. E. Perkins L. J. Callan B. E. Holian K. E. Johnston

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ENCLOSURE FIGURE 1 - U3 BEST ESTIMATE GROWTH RATES FIGURE 2 - U3 UPPER 95 GROWTH RATES FIGURE 3 - NUMBER OF CRACKS

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0 T 38 48 58 68 78 88 NUMBER OF CRACKS Prediction presented to NRC Staff July 12, 1995 Prediction based on MRPC POD curve and >vithout 'Weibull setback optimization

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