ML20137M097

Forwards Rept of SG Tube Inservice Insp Results Which Provides Description of Number & Extent of Tubes Inspected, Location & Percent wall-thickness Penetration for Indication of Imperfection & Identification of Tubes Plugged

ML20137M097
Person / Time
Site:	Davis Besse
Issue date:	03/27/1997
From:	Jeffery Wood CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2452, NUDOCS 9704080012
Download: ML20137M097 (6)

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.CENTERDOR ENERGY 5501 N. State Route 2 -

419 249-2300 John K. Wood Oak Harbor. CH 43449 FAX: 419-321-8337 Vce Presdent - Nurjear Daves4 esse Docket Number 50-346 License Number NPF-3 SerialNumber 2452 March 27, 1997 l

United States Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

Subject:

Report of Steam Generator Tube Inservice inspection Results F

Ladies and Gentlemen:

i The enclosed report is submitted in accordance with the Davis-Besse Nuclear Power Station (DBNPS), Unit Number 1, Operating License, Appendix A, Technical Specifications. Technical Specification (TS) Surveillance Requirements 4.4.5.5.b and 6.9.1.5.b require Toledo Edison to submit the results of the Steam Generator (SG) tube

. inservice inspection performed in accordance with TS 4.4.5.0. The tubing in the Once Through Steam Generators (OTSGs) at the Davis Besse Nuclear Power Station was

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examined in April,1996, during the Tenth Refueling Outage (April 8 - June 2,1996).

This report provides a description of the number and extent of tubes inspected, the location and percent wall-thickness penetration for each indication of an imperfection and the identification of the number and location of tubes plugged or sleeved.

The steam generator tube eddy current examinations were performed utilizing a Bobbin Coil Probe, a Motorized Rotating Pancake Coil (MRPC) Probe, a Sleeve Bobbin Coil Probe, and a Plus Point Coil Probe. The Bobbin Coil Probe was used to perform the j

standard American Society of Mechanical Engineers (ASME) Code Section XI examinations of the tubes and the auxiliary feedwater header gap measurement. The MRPC technique was used to confirm and characterize Bobbin Coil Probe indications and to size wear indications on the tubes. Tube sleeves were examined the length of the sleeve with the Sleeve Bobbin Coil Probe and with a Plus Point Coil Probe at the upper and lower sleeve-to-tube rolls.

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Docket Number 50-346 License Number NPF-3 l

Serial Number 2452.

Page 2 i

Should you have any questions or require additional information, please contact Mr.

James L. Freels, Manager - Regulatory Affairs, at (419) 321-8466.

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truly yours, KAS/laj enclosure l

cc: A. B. Beach, Regional Administrator, NRC Region III A. G. Hansen, DB-l >NRC/NRR Project Manager S. Stasek, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board i

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' Docket Number 50-346 -

' License Number NPF-3

e. : -

Serial Number 2452 i

Enclosure 5

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Davis-Besse Nuclear Power Station Tenth Refueling Outage i

Steam Generator Report -

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i Docket Number 50-346 License Number NPF-3 Serial Number 2452 Enclosure

- Page1 4

i Number and Extent of Tubes Inspected Steam Generator 1-1 i

In Steam Generator 1-1,3094 tubes were examined full length. Tubes with percent through-wall (%TW) indications are listed on the next page. Sixty-six sleeved tubes were j

examined with a Sleeve Bobbin Coil Probe and a Plus Point Coil Probe. No indications of through-wall degradation were found. One hundred ninety-six tubes were examined to determine their proximity to the internal auxiliary feedwater header. All tubes were -

determined to have a gap greater than 0.250 inches.

Steam GeneratG j

In Steam Generator 1-2,3101 tubes were examined full length with the exception of one

' tube. Only the sleeved portion of this tube was examined as access from the lower tube j

end was restricted by the data acquisition system. Tubes with percent through-wall

- (%TW) indications are listed on the next page. Forty sleeved tubes were examined with a Sleeve Bobbin Coil Probe and a Plus Point Coil Probe. No indications of through-wall i

degradation were found. One hundred eighty-one tubes were examined to determine their proximity to the internal auxiliary feedwater header. All tubes were determined to have a gap greater than 0.250 inches.

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Docket Number 50-346 License Number NPF-3 Serial Number 2452 Enclosure Page 2 Location and Percent of Wall Thickness Penetration for Each imperfection STEAM GENERATOR l-1 ROW TUBE REFERENCE DISTANCE'

%TW LOCATION FROM REFERENCE i

14 74 12S

-0.23 17 15 78 14S

-0.61 8

25 97 10S

+ 0.72 5

30 104 10S

-0.70 10 59 122 09S

+0.73 12 60 128 10S

+ 0.54 10 61 121 09S

+0.66 8

61 125 10S

+0.48 8

64 27 04S

-0.55 12

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69 2

12S

+1.12 10 101 124 12S

-0.60 12 115 114 07S

-0.70 15 121 90 07S

+0.66 7

122 104 10S

-0.64 21 128 94 10S

-0.60 15 129 93 10S

-0.64 13 138 75 10S

-0.72 9

141 68 14S

+0.36 12 147 33 10S

+0.59 11

' + is distance above the reference point and - is the distance below the reference point.

STEAM GENERATOR 1-2 ROW TUBE REFERENCE DISTANCE'

%TW LOCATION FROM REFERENCE 52 1

12S

+ 0.66 25 52 1

13S

-0.66 23 74 1

14S

+0.62 11 87 8

03S

+0.73 10 132 1

09S

+0.07 15 133 7

10S

+0.59 9

146 34 10S

+0.56 10 146 37 10S

+0.62 17 148 30 10S

-0.67 12 149 26 10S

+0.62 8

' + is distance above the reference point and - is the distance below the reference point.

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. c.,;.,

,.. Docket Number 50-346 '

. License Number NPF-3 SerialNumber 2452

' Enclosure.

Page 3 Tubes Plugged or Sleeved Steam Generator 1-1 Tube 10-64 (row 10-tube 64) was plugged in Steam Generator 1-1. This tube was characterized as having a manufacturing burnish with no loss of wall thickness.

Ilowever, since its signal amplitude had increased from pr::vious examinations, it was a

_ plugged as a preventive measure. No tubes were sleeved in this Steam Generator.

l Steam Generator 1-2 Tubes 3-34,29-104,58-119,78-52, and 110-80 were plugged in Steam Generator 1-2.

i' Tubes 3-34,29-104, and 78-52 contained through wall-degradation which was

. characterized by the MRPC Probe as volumetric. These tubes were plugged as a preventive measure. Tube 110-80 was characterized as having a manufacturing burnish by the MRPC Probe. Although its signal phase and amplitude did not change from

. previous examinations, it was plugged as a preventive measure because the burnish was in a region'of outside (OD) deposits on the tube. Tube 58-119 exhibited an axial crack

. indication in the roll transition area in the Upper Tube Sheet. A portion of this tube was -

. removed for further examination, resulting in the plugging of this tube. No tubes were sleeved in this Steam Generator.

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