LIC-09-0083, Response to Request for Additional Information Regarding Steam Generator Tube Inservice Inspections During 2008 Refueling Outage

Response to Request for Additional Information Regarding Steam Generator Tube Inservice Inspections During 2008 Refueling Outage

ML093000157
Person / Time
Site:	Fort Calhoun
Issue date:	10/16/2009
From:	Clemens R Omaha Public Power District
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LIC-09-0083
Download: ML093000157 (10)

Text

1 Omaha Public Power Disftrct 444 South 16th Street Mall Omaha, NE 68102-2247 October 16, 2009 LIC-09-0083 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

References:

1. Docket No. 50-285

2. Letter from OPPD (R. P. Clemens) to NRC (Document Control Desk),

"Fort Calhoun Station (FCS), Unit No. 1, Steam Generator Eddy Current Test Report - 2008 Refueling Outage," dated December 9, 2008 (LIC-08-0120) (ADAMS Accession No. ML083440629)

3. Email from NRC (L. E. Wilkins) to OPPD (M. Edwards), "Request for Additional Information Regarding Steam Generator Tube Inservice Inspections During the 2008 RFO," dated October 7, 2009 (ADAMS Accession No. ML092800205)

SUBJECT:

Response to Request for Additional Information (RAI)

Steam Generator Tube Inservice Inspections During Refueling Outage at Fort Calhoun Station, Unit No. 1 Regarding the 2008 In Reference 2, pursuant to Technical Specification 3.1.7(3), the Omaha Public Power District (OPPD) submitted the FCS Steam Generator Eddy Current Test Report summarizing testing performed during the 2008 Refueling Outage.

In Reference 3, the NRC requested additional information regarding the Reference 2 submittal.

OPPD's response is attached.

AOO Employment with Equal Opportunity

U. S. Nuclear Regulatory Commission LIC-09-0083 Page 2 No regulatory commitments are made in this letter. If you should have any further questions, please contact Mr. Bill R. Hansher at (402) 533-6894.

Sincerel, 7.'. Clemens Division Manager Nuclear Engineering RPC/MLE/mle Attachments:

1. Response to NRC RAI

2. Tubesheet Map

3. Sketch of Steam Generator c:

E. E. Collins, NRC Regional Administrator, Region IV L. E. Wilkins, NRC Project Manager J. C. Kirkland, NRC Senior Resident Inspector

LIC-09-0083 Page 1 Response to Request for Additional Information (RAI) Regarding Steam Generator Tube Inservice Inspections During the 2008 Refueling Outage at Fort Calhoun Station, Unit No. 1 NRC RAI No. 1 Please provide the following information pertaining to your steam generators (SGs):

" a tubesheet map depicting the row and column numbers a sketch of the SG depicting the tube support naming convention the thickness of the tubesheet with and without cladding the design/size of the anti-vibration bars (i.e., rectangular shape, 2 inches wide, 0.1 inches thick)

OPPD Response Attachments 2 and 3 provide the requested information.

NRC RAI No.: 2 On page 3 of your report, it states that the broached supports are chamfered at both the top and bottom edges. Please describe the exact design.

oPPD Response Chamfer is a bevel or rounded edge specified at a broached support opening to reduce the likelihood of wear caused by a sharp-machined edge.

A

.O 6TnNISH BY 08A_6=Nr MAHINE)

ARRANGEMENT OF HOLES SECTION AA CETAIL O" HO*,E FLAT-LAND AREA NRC RAI No. 3 Please discuss whether the two bulges identified in two different tubes in SG RC-2B were-present in the baseline inspection and discuss the cause of the bulges.

LIC-09-0083 Page 2 OPPD Response A.Bulge (BLG) is a condition where the tubing's outside diameter is greater than normal.

Both bulges are located in the U-bend section of the tube and they do not produce a large eddy current testing (ECT) voltage response (<

.50 volts).

They are manufacturing anomalies created as a result of the bending process.

Both bulges were present during the shop base line inspection, and the 1st In-Service Inspection (ISI). See table below.

During the 1st ISI, both bulges were detected by the bobbin coil exam and inspected with a motorized rotating probe coil (MRPC) probe with a plus point coil. Test results showed that no defects were found (NDF).

SG RC-2B Exam Row Col.

Volts DEG.

IND.

Loc.

Inches

-2008.

54 110

.49 0

BLG A05 6.18 1 st I n-Service 54 110

.47 3

BLG

A05, 6.06 Shop Baseline

'2008 56 114

.42 2

BLG A05 6.1.6 1 st I1n-Service 2.005 56 114

.42 4

BLG A05 6.18

.Shop Baseline NRCRAI No.4.

On page. 9 of your report, it states that three dents/dings were identified in three different tubes in SG RC-2A and one new dent was identified in SG RC-2B. Please discuss the cause and the severity (voltage) of the dents.

OPPD Response A review of the shop baseline inspection data was performed and it was determined that one of the indications found in RC-2A was also present during the shop baseline inspection but was not called out in the shop baseline report. The other indications, two in RC-2A and one in RC-2B, are approximately 1 volt (see table below). Due to the small magnitudeof the indications, the cause is indeterminable.

LIC0-09-0083 Page 3 SG RC-2A Exam Row Col.

Volts DEG.

IND.

Loc.

Inches 2008 34 66 1.07 170 DNT 02H

-.38 1st In-Service 2008 50 76 1.08 170 DNT 04H 2.93 1st In-Service 2008 2

60 1.44 168 DNG 05H

.19 1st In-Service 20051,,0 2

60 1.49 167 Not 05H

.60 Baseline Reported SG RC-2B Exam Row Col.

Volts DEG.

IND.

Loc.

Inches 2008.

2 64 1.03 172 DNT 01H 30.73 1st In-Service

LIC-09-0083 Page 1 Tubesheet Map

LIC-09-0083 Page 2 Fen Calhounl UnHi 1 1SG 20 60 70 eo 10 20 100 ISO loo 90 go so

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1 1o0 00 7o 80 so 20 21 t0 so 20 30 3

so 60 70 cc No. of Tube 5,200 Model : MHI-4*TT no 080 11 120 Tubesheet Map (Columns depicted on x-axis, Rows on y-axis)

LIC-09-0083 Page 1 Tube Support and Tubesheet Data

LIC-09-0083 Page 2 A05 A06 A04

+A07 A03 A08 A02 A09 A01 A10

+

i,,:

i..

05H 05C 04H 04C

+

+

t T

03H 03C

4.

+

T t

02H 02C

+

4.

+

01H 01C

4.

÷.

TSH TSC TEH TEC A sketch of the SG depicting the tube support naming convention.

LIC-09-0083 Page 3 Tube-sheet Data:

Hole diameter -

Pitch -

Thickness -

Expansion process -

Tube Support Data:

0.759 inches 1.00 inches 25.57 inches including 0.37 inches Inconel 690 cladding Mechanical hard roll at primary face, hydraulic expansion remainder Hole geometry -

Thickness -

Broach land width Material -

Broached support, 1 inch on center 1.38 inches 0.18 inches 405 Stainless Steel Anti-Vibration Bar Data:

Width -

Thickness -

Material-Shape -

Tube Data:

0.59 inches 0.11 inches 405 Stainless Steel Rectangular ID-0.750 inches 0.664 inches Wall Thickness -

Number of tubes -

U-Bend radius:

Maximum -

Minimum -

0.043 inches 5,200 51 inches 3.5 inches

• 'All dimensions are nominal.