ML17310A343

Requests Addl Info in Reviewing SG Tube Insps & Evaluations Conducted as Result of SG Tube Rupture & Other Tube Degradation Detected During Current Refueling Outage,As Soon as Possible

ML17310A343
Person / Time
Site:	Palo Verde
Issue date:	06/15/1993
From:	Trammell C Office of Nuclear Reactor Regulation
To:	Conway W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
References
TAC-M86178, NUDOCS 9306180333
Download: ML17310A343 (8)

Text

Pocket No. 50-529 Hr. William F.

Conway Executive Vice President, Nuclear Arizona Public Service Company P.O.

Box 53999

Phoenix, Arizona 85072-3999 June 15, 1993

SUBJECT:

STEAM GENERATOR TUBE INSPECTION AND EVALUATION PALO VERDE NUCLEAR GENERATING STATION (TAC NO. H86178)

In reviewing the steam generator tube inspections and evaluations that you are conducting as a result of the steam generator tube rupture and other tube degradation detected during the current refueling outage, we have determined that we will need written responses to the enclosed questions.

You should respond to these questions promptly (in the order of a few days),

so that the NRC staff can keep abreast of the work that you are doing and expedite its review of this matter before startup of the unit.

To further this objective, we will provide you questions such as those enclosed as they are identified, and not wait to collect a complete set before issuance.

This request for information affects fewer than 10 respondents.

Therefore, it is not subject to Office of Management and Budget review under Pub.

L.96-511.

Please contact us should you have any questions regarding this request.

Sincerely,

Enclosure:

Request for Additional Information cc w/enclosure:

See next page DISTRIBUTION:

Original signed by Charles M. Trammell, Sr. Project Manager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation Docket File JRoe CTrammell OGC 15B18 HConrad JHuscara NRC 8 Local PDRs EAdensam LTran ACRS (10)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555.0001 June 15, 1993 Docket No. 50-529 Mr. William F.

Conway Executive Vice President, Nuclea}

Arizona Public Service Company P.O.

Box 53999

Phoenix, Arizona 85072-3999

SUBJECT:

STEAM GENERATOR TUBE INSPECTION AND EVALUATION PALO VERDE NUCLEAR GENERATING STATION (TAC NO. M86178)

In reviewing the steam generator tube inspections and evaluations that you are conducting as a result of the steam generator tube rupture and other tube degradation detected during the current refueling outage, we have determined that we will need written responses to the enclosed questions.

You should respond to these questions promptly (in the order of a few days),

so that the NRC staff can keep abreast of the work that you are doing and expedite its review of this matter before startup of the unit.

To further this objective, we will provide you questions such as those enclosed as they are identified, and not wait to collect a complete set before issuance.

This request for information affects fewer than 10 respondents.

Therefore, it is not subject to Office of Management and Budget review under Pub.

L.96-511.

Please contact us should you have any questions regarding this request.

Sincerely,

Enclosure:

Request for Additional Information cc w/enclosure:

See next page fjg.~r Charles M. Trammell, Sr. Project Manager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation

'l tt

Mr.

Wi 1 1 i am F.

Conway Arizona Public Service Company Palo Verde CC:

Mr. Steve Olea Arizona Corporation Commission 1200 W. Washington Street

Phoenix, Arizona 85007 James A. Beoletto, Esq.

Southern California Edison Company P. 0.

Box 800

Rosemead, California 91770 Senior Resident Inspector Palo Verde Nuclear Generating Station 5951 S. Wintersburg Road

Tonopah, Arizona 85354-7537 Regional Administrator, Region V

U. S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596 Mr. Charles B. Brinkman, Manager Washington Nuclear Operations ABB Combustion Engineering Nuclear Power 12300 Twinbrook Parkway, Suite 330 Rockville, Maryland 20852 Mr. William A. Wright, Acting Director Arizona Radiation Regulatory Agency 4814 South 40 Street

Phoenix, Arizona 85040 Chairman Maricopa County Board of Supervisors 111 South Third Avenue

Phoenix, Arizona 85003 Jack R.

Newman, Esq.

Newman

& Holtzinger, P.C.

1615 L Street, N.W., Suite 1000 Washington, D.C.

20036 Mr. Curtis Hoskins Executive Vice President and Chief Operating Officer Palo Verde Services 2025 N. 3rd Street, Suite 220

Phoenix, Arizona 85004 Roy P.

Lessey, Jr.,

Esq.

Bradley W. Jones, Esq.

Akin, Gump, Strauss, Hauer and Feld El Paso Electric Company 1333 New Hampshire Ave., Suite 400 Washington, D.C.

20036 Mr. Thomas R. Bradish, Manager Nuclear Regulatory Affairs Arizona Public Service Company P. 0.

Box 52034

Phoenix, Arizona 85072-2034

II 1

RE VEST FOR ADDITIONAL INFORMATION 1.

Pi 1 gering Noise.

a.

Please provide frequency distributions of vertical noise amplitude at Palo Verde Units 1, 2,

and 3, respectively.

b.

Please provide the voltage of all bobbin indications found to be single axial indications (SAIs) or multiple axial indications (MAIs) by motorized rotating pancake coil (MRPC).

Also provide the corresponding vertical noise amplitude.

c.

APS has reported that signal-to-noise (S/N) ratios ranged to a maximum of 8. 1: 1 at NSI (no bobbin indication) locations.

What was the minimum S/N ratio7 2.

3.

Tubes exhibit enhanced noise in U-bend regions (particularly at the tangent point) when the bobbin is used due to the curvature of the tubing.

This noise is in addition to pilgered-induced noise.

Please provide frequency distribution of total vertical noise amplitude in the U-bend regions.

What is the explanation for the lack of crack indications in the U-bend region above the batwing supports Please provide a description of alternate eddy-current probe designs considered for use at Palo Verde.

Describe their advantages and disadvantages and the technical basis for selecting the probes actually used.

Given the relatively poor performance of the bobbin probe inspections and the slow inspection speed which can be achieved with MRPC, what is the basis for not using ultrasonic testing (UT) to detect cracks?

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