ML20207E653
| ML20207E653 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/26/1999 |
| From: | Jain S DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20207E659 | List: |
| References | |
| L-99-024, L-99-24, NUDOCS 9903110027 | |
| Download: ML20207E653 (5) | |
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Beav Valley Power Station Shippingport, PA 15077-0004 r i e Pr sident February 26, 1999 Fax 7 4
69 Nuclear Pow Mon L-99-024 U. S. Nuclear Regulatory Commission Attention: Document Control Desk j
Washington, DC 20555-0001
Subject:
Beaver Valley Power Station, Unit No.1 Docket No. 56 334, License No. DPR-66 Response to Request for Additional Information Concerning License Amendment Request No. 261
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This provides the response to a request for additional information conceming License Amendment Ret est (LAR) No. 261 submitted by letter dated November 11,1998. The LAR requeste/
extension of the Unit I steam generator surveillance interval to 4
coincide with t.,13* refueling outage or the end of 500 effective full power days, whichever is
- 3. mer. The requested infonnation is provided in the attachments to i
formally docket information discussed during a conference call with the NRC staff on January 21,1999, and formally requested by letter dated February 4,1999.
Reauest 1 i
For each degradation mechanism, provide a general description of the methodology for performing the operational assessment for End of Cycle 13 and a description of the flaw y
growth rate and eddy current measurement error allowances used in the assessments and
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i how they were determined. For Primary Water Stress Corrosion Cracking (PWSCC), the j
description should include an explanation of the model for assessing accident leak rate 1
and the technical basis for the model.
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Response 1 "An Operational Assessment of Steam Generator Tubing at Beaver Valley Unit 1, Cycle 13" is provided in Attachment A to address these concerns. The postulated leak U
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DEllVERING 9903110027 990226 PDR ADOCK 05000334 0 0 A LIT Y P
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j Beaver Valley Power Stati::n, Unit No. I t
I Response to RAI Concerning LAR No.'261 -
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Page 2
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rates described in Attachment A for PWSCC were calculated as follows:
Leak rate calculations for normal operating and accident conditions are provided in j
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Reference 1 based on curve fits to a series of Pipe Crack Evaluation Program (PICEP) (Reference 2) calculations. The leak rate is expressed as a function of l
differential pressure, crack opening area and crack length. These equations may be used for either circumferential or axial cracks. To make the conversion from one geometry to another, only the correct crack opening area equations need to be 1
applied.- The Electric Power Research Institute (EPRI) Ductile Fracture Handbook l
(Reference 3) provides this infonnation. A double iteration of a plastic zone correction to the axial crack length provides the appropriate incorporation of plasticity effects on the calculation of axial crack opening areas.
i As described in Reference 1, benchmarking of the leak rate equations is based on j
the comparison of measured versus calculated leak rates.- Several series of leak i
tests of tubes with axial cracks were included in the benchmarking effort.
Measured leak rates for fatigue crack samples and stress corrosion cracked samples i
were compared to calculated leak rates. This benchmarking effort concluded that l
the leak rate equations provide an excellent bounding result. Smooth fatigue cracks i
do not exhibit the tortuous crack path produced by the corrosion degradation
- process. Hence, good correspondence of calculated leak rates and measured leak i
rates for fatigue crack samples demonstrates the validity of utilizing the calculated leak rates as a good upper bound value for the expected leak rate behavior of tubes degraded by stress corrosion.
Rgauest 2 What degradation mechanisms were in-situ tested? How were samples selected? How were conclusions derived? For the case of PWSCC at tight radius U-bends, what were the leak rates when tested at the postulated Main Steam Line Break accident pressure?
Resoonse 2
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" Summary of In Situ Testing Performed at Beaver Valley Unit 1 During IR12" is provided in Attachment B to address these concerns.
Sincerely, Sushil C. Jain
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Beaver Valley Power Station Unit No.1 0
Response to RAI Concerning LAR No. 261 i
Page 3 c:
Mr. D. S. Collins, Project Manager Mr. D. M. Kern, Sr. Resident Inspector Mr. H. J. Miller, NRC Region I Administrator
References:
1.
" Depth-Based Structural Analysis Methods for Steam Generator Circumferential Indications," EPRI Report TR-107197-P1, Interim Report, November 1997.
2.
"PICEP: Pipe Crack Evaluation Program (Revision 1)," Electric Power Research Institute, NP-3596-SR, Revision 1, December 1987.
3.
Zahoor, A., " Ductile Fracture Handbook," EPRI Report NP-6301-D, N14-1, Project -
1757-69, June 1989.
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AFFIDAVIT FOR APPLICATION OF AMENDMENT j
l COMMONWEALTH OF PENNSYLVANIA)
) SS:
COUNTY OF BEAVER
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Subject:
Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 Response to Request for Additional Information Concerning License Amendment Request No. 261 Before me, the undersigned notary public, in and for the County and Commonwealth aforesaid, this day personally appeared Sushil C. Jain, to me known,
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who being duly sworn according to law, deposes and says that he is Senior Vice President, Nuclear Services of the Nuclear Power Division, Duquesne Light Company, j
he is duly authorized to execute and file the foregoing submittal on behalf of said Company, and the statements set forth in the submittal are true and correct to the best of his knowledge, information and belief.
p_
W Sushil C. Jain
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Subscribed and sworn to before me onthigh ayof fg[Lubu
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" ' '$d* al$1 Seal Tracey A. Baczek, Notary Public My m
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.6 Member. Pennsytvania Association of Notares
ATTACHMENT A Beaver Valley Power Station, Unit No. 1 l
Response to Request for Additional Information Concerning License Amendment Request No. 261 An operational Assessment of Steam Generator Tubing at Beaver Valley Unit 1, Cycle 13 1
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