ML17313A207

Discusses SG Operational Assessment for Unit 3 Cycle 7 Operation.Util Concluded,Interim Unit 3 Operation Justified for at Least 10.6 Months

ML17313A207
Person / Time
Site:	Palo Verde
Issue date:	02/06/1998
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
102-04073-JML-S, 102-4073-JML-S, NUDOCS 9802180081
Download: ML17313A207 (6)

Text

CATEGORY 1 REGULA RY INFORMATION DISTRIBUTI SYSTEM (RIDS)

Ir ACCESSION NBR:9802180081 DOC.DATE: 98/02/06 NOTARIZED: NO DOCKET FACIL:STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH.NPPKP AUTHOR AFFILIATION LEVIN&,J.M. Arizona Public Service Co; (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Discusses SG operational assessment for Unit 3 Cycle 7 operation. Util concluded, interim Unit 3 operation justified for at least 10.6 months.

DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: OR Submittal: General Distribution NOTES:Standardized plant. 05000530E RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL " ID CODE/NAME LTTR ENCL 0 PD4-2 LA PD4-2 PD CLIFFORD,J INTERNAL: ACRS E CENTER 01 NRR/DE/ECGB/A NRR/DE/EMCB NRR/DRCH/HICB NRR/DSSA/SPLB NRR/DSSA/SRXB NUDOCS-ABSTRACT OGC/HDS2 EXTERNAL: NOAC NRC PDR D

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NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 TOTAL NUMBER OF COPIES REQUIRED: LTTR 14 ENCL

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James M. Levine TEL (602)393-5300 Mail Station 7602 Palo Verde Nuclear Senior Vice President FAX (602)3936077 P.O. Box 52034 Generating Station Nuclear Phoenbt, AZ 85072-2034 102-04073 -JML/SAB/RMW U. S. Nuclear Regulatory Commission February 6, 1998 ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001

References:

1. Letter 102-04040-JML/AKK/JRP, dated November 18, 1997, from J. M. Levine, Senior Vice President, Nuclear, APS to USNRC. T

. 2 Letter,102-03931-JML/AKK/JRP, dated May 09, 1997, from J. M. Levine, Senior Vice President, Nuclear, APS to USNRC.

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 3 Docket No. STN 50-530 Steam Generator Operational Assessment for Unit 3 Cycle 7 Operation Reference 1 submitted to the USNRC an interim steam generator operational assessment that was performed for Unit 3 Cycle 7 operation. As indicated in Reference 1, the installation of shroud holes was completed in both of the Unit 3 steam ge'nerators (SG 31 and 32) during the sixth refueling outage for Unit 3 (U3R6). Therefore, Unit 3 .

could be expected to experience steam generator tube wear conditions similar to that.

which was observed during Unit 2 Cycle 7 operation. The Unit 3 interim operational assessment conservatively adopted the assumption that the worst Unit 2 tube wear indication observed in the Batwing Stay Cylinder (BWSC) region had developed from 0% to 93% in a 16.5 month operating cycle. The Unit 3 interim analysis also conservatively assumed that any tube in the BWSC region is susceptible to an accelerated growth rate, despite the fact that the tubes which may be affected in SG 31 and SG 32 have been either preventatively plugged or plugged for cause. Based on these assumptions, APS concluded that interim Unit 3 operation was justified for at least 10.6 months. This time period would allow acceptable operation of Unit 3 until February 15, 1998.

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U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Steam Generator Operational Assessment for Unit 3 Cycle 7 Operation Page 2 APS committed to perform a final steam generator operational assessment for Unit 3 Cycle 7 operation by January 15, 1998. The final assessment for Unit 3 has been completed and incorporates a determination of the applicability of the Unit 2 seventh refueling outage (U2R7) steam generator eddy current testing results to Unit 3 operation. Based on the determination that the wear phenomenon continues to behave as indicated in the operational assessment report for Unit 2 Cycle 7 that was submitted by APS in Reference 2, APS concludes that Unit 3 may safely operate for the full duration of the current fuel cycle. The final assessment results for Unit 3 indicate a low probability (4x10') that wear rates in the BWSC region will result in an indication which fails to satisfy the structural (35P) and leakage integrity limits defined in Draft Regulatory Guide 1074, Steam Generator Tube Integrity.

COMMITMENTS MADE AS PART OF THIS DOCUMENT This letter does not imply or make any commitments.

Please contact Mr. Scott Bauer at (602) 393-5978 if you have any questions or comments.

Sincerely, JML/SAB/RMW/rlh cc: E. W. Merschoff J. W. Clifford J. H. Moorman K. E. Perkins

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