ML17311A303

Forwards Table 1,comparison of PVNGS ECT & Recent ABB-CE Plant Experience & Table 2,addl Program Requirements/ Enhancements,Per Request as Result of Util Presentation at 940822 Meeting in Rockville,Md

ML17311A303
Person / Time
Site:	Palo Verde
Issue date:	09/22/1994
From:	Stewart W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
102-03124-WLS-A, 102-3124-WLS-A, NUDOCS 9409280244
Download: ML17311A303 (8)

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1 REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION'BR: 940 FACIL:STN-50-528 STN-50-529 STN-50-530 AUTH.NAME STEWART,W.L.

RECIP.NAME 9280244 DOC.DATE: 94/09/22 NOTARIZED: NO DOCKET Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 Palo Verde Nuclear Station, Unit 2, Arizona Publi 05000529 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTHOR AFFILIATION Arizona Public Service Co.

(formerly Arizona Nuclear Power RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

P SUBZECT: Forwards Table 1,comparison of PVNGS ECT

& recent ABB-CE plant experience 6 Table 2,addi program requirements/

enhancements,per request as result of util presentation at 940822 meeting in Rockville,MD. ~

DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR ENCL SIZE:

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General Distribution NOTES:STANDARDIZED PLANT Standardized plant.

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NOTE TO ALL"RIDS" RECIPIENTS:

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Arizona Public Service Company P.O. BOX 53999

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PHOENIX, ARIZONA85072-3999 WILLIAML. STEWART EXECUTIVEVICEPRESIDENT NUCLEAR U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington DC 20555 102-03124-WLS/AKK/JR P September 22, 1994

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Units 1, 2, and 3 Docket Nos. STN 50-528/529/530 Eddy Current Program Review File: 94-056-026 During a meeting between Arizona Public Service Company (APS) and the NRC in Rockville, MD on August 22, 1994, APS presented the status of the steam generator activities at PVNGS.

In addition to the status, a discussion of recent ABB-CE plant experiences was presented, including the PVNGS program vs recent industry experiences.

As a result of this presentation, the NRC requested, through their project manager, APS compare its program with that of recent ABB-CE plant experiences.

In accordance with this request, enclosed please find Table 1, Comparison of PVNGS Eddy Current Test (ECT) and Recent ABB-CE Plant Experience, and Table 2, Additional Program Requirements/Enhancements.

In addition to the information provided in the ericlosure, APS confirms that the ECT program used during the Unit 1 fourth refueling outage (U1R4) was adequate and the need to re-review the ECT data is not necessary based on recent ABB-CE plant experiences.

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

WLS/AKK/JRP/rv Enclosure cc:

L. J. Callan K. E. Perkins K. E. Johnston B. E. Holian 9409280244 940922 PDR ADQCK 05000528

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Eddy Current Program Review Several recent utilitypresentations have been provided to the NRC Staff regarding improvements/refinements in ECT equipment, scope, and techniques for detection ofcircumferential defects. In an effort to benchmark the ECT inspections at PVNGS during U1R4 in November 1993, APS has compared its U1R4 program plan with the noted 1994 ABB-CEplant improvements.

Table 1: Comparison ofPVNGS ECT and Recent ABB-CEPlant Experience Improvement/Refinement Implemented AtU1R4 Comments 100% MRPC inspection ofhot leg tubesheet transition region Review ofPancake Coil Terrain Plot ofeach tube Yes Yes 20% MRPC inspection ofcold leg tubesheet transi-tion also conducted in SG 1-2 APS ECT procedure requires analyst review ofboth terrain plot (C-scan) and lissajous presentation Larger (0.115) pancake coil and low loss cable Yes Plant B reported improved signal to noise ratios and reduced impedance with this equipment improve-ment Utilized Ultrasonics (UT) to assess MRPC results Training Yes Yes APS demonstrated consistent results between MRPC and independent UT examinations (See report sub-mitted to NRC via letter 102-02716 dated 11/2/93)

Analysts trained and tested on both axial and circum-ferential indications. Training included lessons learned from Unit2 tube pull ofgeometry indica-tions. Training includes experience/lessons learned from ABB-CEplants.

Independent Primary and Secondary Analyses Yes APS utilizes independent analysis teams from CONAMand ABB-CE

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Based on the critical nature ofcircumferential indications at ABB-CEplants, additional enhancements are employed/credited at Palo Verde. APS believes the followingitems, in Table 2, further indicate a high level ofconfidence in the ability to detect ID/OD circum-ferential cracks in PVNGS steam generators.

Table 2: Additional Program Requirements/Enhancements Program Requirement/Enhancement Filters not permitted for detection In-situ Pressure Test Tubesheet exam typically performed as push (ris-ing) through transition region Physical differences between PVNGS and other plants reduce effect ofinterfering signals ID/ODcircumferentiaVaxial EDMnotch calibration standard utilized as needed Tracking ofanalyst performance Comment Avoid possible signal suppression Verifystructural integrity and conservatism ofECT exam Reduce/prevent liftoffeffect due to transition

1. No evidence oftubesheet denting

2. No evidence ofhigh copper levels in sludge Analyst assistance Comparison and feedback made on daily basis

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