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 PublicPowerDisftrct 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) Regarding Steam Generator Tube Inservice Inspections During the 2008 Refueling Outage at Fort Calhoun Station, Unit No. 1 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 .O6TnNISH 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 1 st In-Service Inspection (ISI). See table below.

During the 1 st 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 In-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 1 st In-Service 2008 50 76 1.08 170 DNT 04H 2.93 1 st In-Service 2008 2 60 1.44 168 DNG 05H .19 1 st 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 1 st In-Service

LIC-09-0083 Page 1 Tubesheet Map

LIC-09-0083 Page 2 Fen Calhounl UnHi 1 1SG 10 70 100 20 20

________00 ~0~0 60~0~~0~ 000000 eo ISO loo 1o0

______ ____- 0 O % O 00000 90 00 go 7o 000.00000 000 aoooo 00.0 0000000000 a0000 0000 2Oo2 0

• 0 aoao 80 ago~ oo o001 ~4~~0 ~

so 00 000000 00.0 00000 0000 0000 0 0

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~~ 2~0 0 0: 0 .00% o 0000go o4 000000 00000 000000~~~ .00ooo0.0 r0 0

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20 t0 so 20 30 3 so 60 70 cc no 080 11 120 No. of Tube 5,200 Model : MHI-4*TT 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

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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 - 0.759 inches Pitch - 1.00 inches Thickness - 25.57 inches including 0.37 inches Inconel 690 cladding Expansion process - Mechanical hard roll at primary face, hydraulic expansion remainder Tube Support Data:

Hole geometry - Broached support, 1 inch on center Thickness - 1.38 inches Broach land width 0.18 inches Material - 405 Stainless Steel Anti-Vibration Bar Data:

Width - 0.59 inches Thickness - 0.11 inches Material- 405 Stainless Steel Shape - Rectangular Tube Data:

ID- 0.750 inches 0.664 inches Wall Thickness - 0.043 inches Number of tubes - 5,200 U-Bend radius:

Maximum - 51 inches Minimum - 3.5 inches

• 'All dimensions are nominal.