ML17311A893

Forwards PVNGS Unit 3 SG Evaluation to Justify Continued Operation of Unit 3 Until Next Refueling Outage Scheduled to Begin 951014.Evaluation Supports Up to 11 Months of Operation Following Midcycle Outage 5

ML17311A893
Person / Time
Site:	Palo Verde
Issue date:	05/19/1995
From:	Stewart W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17311A894	List: ML17311A893
References
102-03364-WLS-S, 102-3364-WLS-S, NUDOCS 9505250063
Download: ML17311A893 (6)

Text

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ACCESSION NBR:9505250063 DOC.DATE: 95/05/19 NOTARIZED: NO DOCKET FACIL:STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH.NAME AUTHOR AFFILIATION STEWART,W.L.

Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION P

Document Control Branch (Document Control Desk) ~

SUBJECT:

Forwards "PVNGS Unit 3 SG Evaluation" to justify continued M R

operation of Unit 3 until next refueling outage scheduled to begin 951014.Evaluation supports up to 11 months of I

operation following Midcycle Outage 5.

DISTRIBUTION CODE:

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TITLE: OR Submittal:

General Distribution NOTES:Standardized plant.

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Arizona Public Service Company P.O. BOX 53999

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PHOENIX. ARIZONA85072-3999 WILLIAML, STEWART EXECUTIVEVICEPAESIDENT NUCLEAR 102-03364-WLS/SAB/JRP May 19, 1995 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Reference:

Letter 102-03013, dated June 20, 1994, from W.L.Stewart, Executive Vice President - Nuclear, APS, to USNRC

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 3 Docket No. STN 60-630 Steam Generator Evaluation This letter transmits the Palo Verde Nuclear Generating Station Unit 3 Steam Generator Evaluation to justify the continued operation of Unit 3 until the next refueling outage scheduled to begin October 14, 1995. The enclosed evaluation supports up to eleven (11) months of operation following Midcycle Outage 5.

The enclosed evaluation contains a Regulatory Guide 1.121 analysis which consists of a methodology similar to the evaluation submitted to the NRC by the referenced letter and presented to the NRC on August 22, 1994, by members of the Palo Verde staff.

Based on more recent discussions with the NRC, APS has incorporated improvements to the engineering models which are discussed in the report. The report also describes the actions taken by APS to provide defense-in-depth in order to prevent a challenge to nuclear safety.

These actions include preventative measures such as chemistry improvements, primary temperature reduction, N-16 monitoring improvements, comprehensive steam generator inspections, and conservative plugging criteria. An improved leak rate monitoring program and administrative limits on primary-to-secondary leakage provide additional assurance that an orderly shutdown will be conducted prior to a rupture. Training of operations personnel for tube rupture events and upgrades to the emergency operating procedures permit faster identification and isolation of the affected steam generator. An analysis was also performed to demonstrate that, in the unlikely event of a main steam line break with consequential multiple tube ruptures, with the current administrative limits on reactor coolant system dose equivalent iodine, the resulting offsite doses are less than 10CFR100 limits.

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U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Steam Generator Evaluation (Unit 3)

Page 2 APS, therefore, concludes that the integrity of Unit 3 Steam Generators will be maintained and the unit can be safely operated until the next scheduled refueling outage at the end of cycle 5.

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

Sincerely, WLS/SAB/JRP/AI Enclosure cc:

L. J. Callan K. E. Perkins B. E. Holian K. E. Johnston I.

Barnes

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