ML17305B323
| ML17305B323 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 01/11/1991 |
| From: | Conway W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 161-03697-WFC-J, 161-3697-WFC-J, NUDOCS 9101220444 | |
| Download: ML17305B323 (6) | |
Text
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR: 9101220444 DOC. DATE: 91/01/11 NOTARIZED: NO DOCKET, 8 FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 AUTH.NAME AUTHOR AFFILIATION CONWAY,W.F.
Arizona Public Service Co.
(formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Provides response to NRC questions re steam generator eddy current exams at facility & request for extension of interval for exam.
DISTRIBUTION CODE:
AOOID COPIES RECEIVED:LTR g ENCL L7 SIZE:
TITLE: OR Submittal:
General Distribution NOTES:STANDARDIZED PLANT 05000528 RECIPIENT ID CODE/NAME PD5 LA TRAMMELL,C INTERNAL: ACRS NRR/DET/ESGB NRR/DST 8E2 NRR/DST/SICB 7E NUDOCS-ABSTRACT OGC/HDS 1 RES/DSIR/EIB EXTERNAL: NRC PDR NOTES COPIES LTTR ENCL RECIPIENT ID CODE/NAME PD5 PD TRAMMELL,C.
NRR/DET/ECMB 9H NRR/DOEA/OTSB11 NRR/DST/SELB 8D NRR/DST/SRXB 8E REG LE 01 NSIC COPIES LTTR ENCL NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE iVASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 27 ENCL
&5-
0
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WILLIAMF. CONWAY EXECUTIVEVICEPRESIDENT NUCLEAR Arizona Public Service Company P.O. BOX 53999
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PHOENIX, ARIZONA85072-3999 161-03697-WFC/JRP January 11, 1991 Docket No.
STN 50-528 Document Control Desk U.
S. Nuclear Regulatory Commission Mail Station Pl-37 Washington, D.
C.
20555
Reference:
Letter from W. F.
- Conway, APS to NRC, dated November 14,
- 1990, (161-03589).
Subject:
Extension of Interval for SG Eddy Current Examination
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 1 Extension of Interval for SG Eddy Current Examination File: 91-F-005-419.05; 91-056-026 This letter is being provided in response to NRC questions regarding steam generator eddy current examinations at PVNGS and the request for an extension of the interval for this examination.
As a result of the NRC's recent review of the 1989 Unit 1 steam generator eddy current examination report, Mr. Trammell, of the NRC staff, requested that APS provide an explanation for not plugging two Unit 1 steam generator
- tubes, which had indications of greater than the Technical Specification limit for through wall wear at the time of the pre-service inspection.
Additionally, he requested that APS describe the administrative controls currently in place to ensure that tubes which require plugging do, in fact, get plugged.
As stated in previous conversations and by the referenced letter, the Unit 1
steam generators 100% pre-service inspection (baseline) was performed during July and August of 1981.
The analysis of the data identified approximately 10 tubes that were required to be plugged because of fabrication errors or damage.
This data analysis was performed by the eddy current contractor and was not independently verified, nor was it required by procedure.
During analysis of the July 1989, 100% eddy current examination data, it was discovered that two tubes in steam generator Pl, R53 L116 and R39 L182, were degraded (i.e.,
82% and 79% through wall indications).
Upon re-review of the 1981 baseline eddy current tapes in 1989, both 'of these indications were present but had not been identified through the data analysis in 1981.
It was also noted in 1989 that neither indication had grown larger since the baseline inspection.
APS attributes not plugging the subject tubes to not having performed an independent verification of the eddy current data analysis in 1981.
9101220444 9'1011l PDR 4DOCK 0500052S PDR
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161-03697-WFC/JRP January 11, 1991 Document Control Desk U.
S. Nuclear Regulatory Commission SG Eddy Current Page Two The procedures used for the 1989 eddy current examination did not require an independent verification of the data analysis;
- however, an independent verification of the data analysis was performed.
The work orders generated to perform the tube plugging included Quality Control (QC) holdpoints to verify that the correct tubes were plugged.
The Inservice Inspection (ISI) engineer performed an independent visual verification of the plugged tubes.
Additionally, the contractor used for the 1989 steam generator tube plugging installation had a step in their procedure which identified APS work order requirements to include QC holdpoint identification for plug location.
A review of the work orders from the 1989 tube plugging indicated that all tubes identified in the eddy current test report have been plugged and that the plugs are in the correct locations.
The present requirements for steam generator eddy current examinations and tube plugging procedurally include an independent verification of the steam generator eddy current data analysis as well as QC holdpoints for verification that plugs are installed in the correct locations.
During the eddy current testing of the Unit 2 steam generators in April 1990, it was discovered that a tube, required to be plugged during the first Unit 2 refueling, had only been plugged on the cold leg side of the steam generator.
The event was described in LER 2-90-005, which was transmitted by letter 192-00660 dated May 15, 1990.
The discovery of this error during the 1990 inspection demonstrates that the process currently in place for steam generator eddy current testing is, capable of determining degraded conditions and implementing corrective actions.
If you have any questions or require additional information, please contact M. E. Powell of my staff at (602) 340-4981.
WFC/JRP/pmm CC:
C.
M.
J.
B.
D. H.
A. C.
A. H.
Trammell Martin Coe Gehr Gutterman
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