ML20245F037
| ML20245F037 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 04/24/1989 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-88-009, IEB-88-9, NUDOCS 8905020242 | |
| Download: ML20245F037 (2) | |
Text
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(
ave Hey Power Staten
- Nppingport. PA 50770X)4 "3N$1., c,oup v
wumms April 24, 1989 jb.
S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
Reference:
Beaver Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 NRC Bulletin 8G-09:
Thimble Tube Thinning in Westinghouse Reactors; Unit No. 2 Inspections Gentlemen:
This submittal is in response to the Reportina Requirements section of NRC Bulletin No.
88-09:
Thimble Tube Thinning In Westinghouse Reactors.
This section stated: Addressees are required to, in accordance with the following schedule, within 30 days of completion of the thimble tube inspections, submit a written response that a) confirms that an inspection program consistent with that requested in Item 1 of Actions Reauested has been established and b) confirms that inspections of the thimble tubes have been performed and that appropriate corrective actions were taken.
Our submittal dated November 7,
1988 provided our initial i
response to this Bulletin.
We stated that a formal program for performing flux thimble tube inspections had not been developed, but committed to having one prior to conducting inspections on Unit No.
(
2.
- However, our submittal did respond to each of the concerns j
l identified in the Actions Recuested section of your letter by l
providing the wear acceptance criterion, inspection frequency and an l
inspection methodology utilized during the initial inspection of the Unit No.
1 thimble tubes.
The same elements as discussed in our i
November 7,
1988 submittal form the basis for our Thimble Tube Examination Program with one exception as stated below.
We had previously stated that any flux thimble tubes exhibiting wear indications in excess of 45% will be removed from service.
This was based on a
15% allowance to account for inspection methodology and wear scar geometry uncertainties.
The inspections conducted on Unit No.
2 had a i 10% uncertainty versus a 15% uncertainty for the inspections performed on Unit No.
1.
The ilifference in uncertainties is due to the use of different vendors.
As a recult, our Thimble Tube Examination Program will take different uncertainties into l
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8905020242 890424 2 fhg PDR ADOCK 05000412f.
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Beaver Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 Page 2 i
l consideration when determining if a
flux thimble tube should be removed from service.
The finite element structural analysis which concluded a flux thimble tube could experience 60% material wear loss j
still remains the basis for determining if a flux thimble may remain in service or not.
Unit No.
2 entered its' first refueling outage on March-17, 1989.
As stated in our earlier submittal, flux thimble tube inspections were scheduled to occur during this outage.
1 I
All flux thimble tube inspections were completed on March 25,
- 1989, in accordance with our Thimble Tube Examination Program discussed above.
One flux thimble had wear indication which required that it be removed from service.
The remaining 49 flux thimble tubes
)
were within our acceptance criteria for remaining in
- service, 1
however, four were repositioned.
If you have any questions regarding this submittal, please contact me or members of my staff.
Very truly yours, 0
l'
( LA Aulm---
D.
Sieber ice President Nuclear Group l.
cc:
Mr. J.
Beall, Sr. Resident Inspector Mr. W. T. Russell, NRC Region I Administrator Mr.
P. Tam, Sr. Project Manager Director, Safety Evaluation & Control (VEPCO) l l
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