ML17310A821

Forwards Response to & Provides Scope of Unit 3 ECT Insp Prior to Commencing Insp

ML17310A821
Person / Time
Site:	Palo Verde
Issue date:	11/17/1993
From:	James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
102-02730-JML-R, 102-2730-JML-R, NUDOCS 9312020498
Download: ML17310A821 (12)

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REGUL ORY INFORNATION DISTRIBUTION SYSTEN (RIDS)

DOCKET 5 05000530 ACCESSION NBR: V312020498 DOC. DATE: 93/11/17 NOTARIZED:

NO FACIL:STN-50-530 Palo Verde Nuclear Station>

Unit 3> Arizona Publi AUTH. NAME AUTHOR AFFILIATION LEVINE> J. N.

Arizona Public Service Co.

<formerly Arizona Nuclear Power RECIP. NANE RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Forwards response to 931004 ltr 5 provides scope of Unit 3 ECT insp prior to commencing insp.

DISTRIBUTION CODE:

A001D COPIES RECEIVED: LTR ENCL SIZE:

TITLE:

OR. Submi tta 1:

Genera l Distribution NOTES: Standardized plant.

RECIPIENT ID CODE/NAME PDV L*

TRAN> L COPIES LTTR ENCL 1

1 2

2 RECIPIENT ID CODE/NAKE PDV PD COPIES LTTR ENCL 1

1 05000530

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F INTERNAL: ACRS NRR/DORS/OTSB NRR/DSSA/SPLB NUDOCS-ABSTRACT OGC/HDS1 EXTERNAL:

NRC PDR b

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NRR/DE/EELB NRR/DRCH/HICB NRR/OSSA/SRXB OCJASPAQ EG FILE 01 WtD NSIC 1

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1 NOTE TO ALL RIDS RECIPIENTS:

PLEASE HELP US TO REDUCE V>'ASTE! CONTACT THE DOCUMENT CONTROL DESK.

ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR iNAME FROM DISTRII3UTION LISTS FOR DOCUih<ENTS YOU DON'T NEED!

TOTAL NUNBER OF COP IES REQUIRED:

LTTR 21 ENCL 19

JAMES M. LEVINE VICE PRESIDENT NUCLEAR PRODUCTION Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034

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PHOENIX, ARIZONA85072-2034 102-02730-JML/RAB/JRP November 17, 1993 U. S. Nuclear Regulatory Commission ATlN: Document Control Desk Mail Station P1-37 Washington, D. C. 20555

Reference:

Letter dated October 4,

1993, from B.

H.

Faulkenberry, Regional Administrator, Region V, USNRC, to W.

F.

Conway, Executive Vice President, Nuclear, APS

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 3 Docket No. STN 50-530 Unit 3 Steam Generator Tube Inspection Plan File: 93-056-026 By letter dated October 4, 1993 (Reference), the NRC required that Arizona Public Service Company (APS) provide the scope of the Unit 3 Eddy Current Testing (ECT) inspection prior to commencing the inspection.

The enclosure to this letter contains the initial inspection scope, the basis for the initial scope, and the criteria for expansion.

Should you have any questions, please contact Richard A. Bernier at (602) 393-5882.

Sincerely, JML/RAB/JRP/rv Enclosure cc:

W. F. Conway B. H. Faulkenberry B. E. Holian J. A. Sloan l

9312020498 931117 PDR 'DOCK,05000530 8

PDR

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STATE OF ARIZONA

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) ss.

COUNTY OF MARICOPA )

I, J.

IVI. Levine, represent that I am Vice President Nuclear Production, that the foregoing document has been signed by me on behalf of Arizona Public Service Company with full authority to do so, that I have read such document and know its

contents, and that to the best of my knowledge and

belief, the statements made therein are true and correct.

J. M. Levine Sworn To Before Me This ~l& Day Of

, 1993.

~P ANNAL>

Notary;Publ,i,c~~j,>>,"';

My Commission Expires

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ENCLOSURE UNIT 3 STEAM GENERATOR TUBE INSPECTION PLAN

UNIT 3 STEAM GENERATOR TUBE INSPECTION PLAN The Unit 3 Steam Generators will be inspected in the mid-cycle. outage (U3M4) for tube defects using Eddy Current Testing (ECT) technology as opposed to ultrasonic or other NDE methods.

The initial inspection scope, the basis for initial scope, and criteria for scope expansion are described below:

Initial Sco e

I Approximately 3800 tubes in the analytical arc as defined by the Unit 2 Steam Generator Tube Rupture Analysis Report will be inspected full length with bobbin coil.

20% Tubesheet Hot (TSH) willbe inspected with Motorized Rotating Pancake Coil (MRPC)

Batwing 1

(BW1) to the first vertical support will be inspected with MRPC (Approximately 200 tubes in the highest susceptible area of the arc).

08H to the firstvertical support willbe inspected with MRPC (Tubes identified from U3R3 ECT data with unresolved ECT signatures).

Basis for Initial Sco e and Criteria for Ex ansion The tube pull results from U2R4 inspection indicated that the bobbin probe is an effective method of scanning for critical axial indications of the type seen in Unit 2.

The detectability studies conducted in Unit 2 indicate that the bobbin coil technique provides a detectability threshold of approximately 50% throughwall in straight runs of tubing.

Since the period of operation from the end of the mid-cycle outage to the next refueling outage is approximately four months, it is not deemed necessary to perform extensive MRPC inspection for the marginal increase in detection sensitivity.

The MRPC sample program of 200 tubes will be performed to confirm the expected sensitivity of the bobbin coil probe in the bend region (BW1 to the first vertical support).

Mock-up testing of square bends using Electro-Discharge Machining (EDM) slots indicates a bobbin threshold of approximately 60% throughwall in the bend region.

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Expansion of MRPC to the full 1800 tube arc program conducted in Unit 1 will be performed if a No Bobbin Indication (NBI) axial crack is detected which is predicted to exceed Regulatory Guide (RG) 1.121 limits.

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The mid-cycle inspection is not a surveillance inspection as defined in PVNGS Technical Specifications.

However, the criteria for expansion must be adequate to ensure marginal tubes are identified while'recognizing that a full surveillance test inspection will be performed in U3R4, approximately four months after the mid-cycle outage. Therefore, the following expansion criteria are established:

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A buffer zone of five tubes without axial crack indications will be maintained from the edge of the bobbin inspected area.

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MRPC will be conducted to resolve ul" code indications (NQI, DTI, SVI, and DSl).'ny circumferential crack at the hotleg tubesheet triggers a 100% MRPC of the hotleg tubesheet area of the affected steam generator.

The Unit 1 arc program of 1800 tubes will be examined by MRPC from the 08H to the vertical support region if an NBI axial crack is detected which is predicted to exceed the RG 1.121 limits.

Tubes will not be pulled from Unit 3 Steam Generators during U3M4 unless a new unexplained failure mechanism is identified by ECT inspection or tube samples are necessary to show compliance with RG 1.121.

No visual examination of Unit 3 Steam Generators secondary side will be conducted in U3M4 as the six inch handholes will not be installed until the next refueling outage.

Conam will be the vendor used to conduct ECT in the U3M4 outage.

There will be no experimental alternate inspection technologies used during U3M4.

NQI - Non-QuantiTctble Indication; DSI - Distorted Support Signal viith Indication; DTI; Distorted Top of Tubesheet with Indication; SVI - Single Volumetric Indication.

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