ML20080R195
| ML20080R195 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/03/1995 |
| From: | Beckham J SOUTHERN NUCLEAR OPERATING CO. |
| To: | Brinkman D NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9503090195 | |
| Download: ML20080R195 (3) | |
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internals Project Issue Management and Resolution March 3,1995 U.S. Nuclear Regulatory Commission Document Control Desk Washington DC 20555 Attention:
Mr. Donald S. Brinkman, Senior Project Manager Project Directorate I-I Division of Reactor Projects -I/II Office of Nuclear Reactor Regulation
Subject:
MPR Brochure Transmitted to the NRC The attached information is in response to your letter of February 3,1995, requesting our evaluation of advertised data that predicts gaps could occur in solid tic rod shroud repair designs, under some preload conditions, when certain key welds fail. Your letter also referenced recent technical questions that the NRC has raised regarding the GE designed repair that is installed on Hatch Unit 1.
As indicated in the attached response, we believe that the BWR Core Shroud Repair Design Criteria and the NRC Staff's Safety Evaluation of those criteria remain valid and no changes are necessary. Our response also states that the BWR Vessel and Internals Project cannot perform an evaluation of repair designs for any vendor or plant. These must be conducted by, or for, the licensee contracting for the repair.
Please feel free to contact me or Robin Dyle, Integration Committee Chairman, at (205) 877-7121, if you have any questions or need additionalinformation.
Sincerely, f
NO
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< T. Beckham,Jr.
Southern Nuclear Operating Company Chairman, BWR Vessel & Internals Project RT.0997.M/kew Reply To:
J. T. Beckham, Jr., BWRVIP Chairman, Southem Nuclear Operating Co.,42 Invernes:
Center Parkway, Birmingham, AL 35242 * (205) 877-7279
- Fax: (205) 802-0393 J
A t' n n n 4 p l 9503090195 950303 i
PDR ADOCK 05000321 i
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J EVALUATION OF ADVERTISED SHROUD REPAIR DATA
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RECEIVED BY NRC
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Summary of Advertised Data The advertised data indicates that gaps could occur at specific shroud welds (H6B,H7 or H8) in solid tie rod designs, under some preload conditions, when certain key welds (H2 and H3) fail.
Summary of NRC Concern i
The consequences of leakage through gaps as large as those indicated in the i
advertised data has not been evaluated by NRC.
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RESPONSE
.1 BWRVIP Repair Criteria and Staff Safety Evaluation The BWR Core Shroud Repair Design Criteria addresses the separation of failed I
- welds, during normal operation, in the following sections:
Sections 5.1.5 and 5.3.1 require repairs to be designed so that there is no.
separation of 360* through wall cracked shroud welds during normal operation.
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. Section 5.2.3 requires,in part, that the design analysis assume that all welds encompassed by the repair are completely failed through wall.
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Section 5.2.3.6 requires, in part, that design preloads be analyzed to a
demonstrate that shroud displacement limits specified in 5.3.1 are met.
l In summary, a repair which meets these design criteria will not permit separation of failed welds, within the scope of the repair, during normal operation.
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- The advertised data received by NRC describes a situation where the repair does not meet the BWR Core Shroud Repair Design Criteria. This does not invalidate either the repair design criteria or the staff's safety evaluation of those criteria.
i Evaluation of Soecific Vendor Designs or Data e
The BWRVIP has not evaluated specific vendor repair designs to determine if j
they comply with the repair criteria. These evaluations are plant specific and
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must be conducted by, or for, the licensee contracting for the repair.
It is the position of the BWRVIP that shroud repairs should meet the repair
-l criteria.
1 Hatch Unit 1 Repair Design Analysis The NRC letter referenced a recent NRC letter to Georgia Power Company -
outlining details of some questions regarding the design analysis of the GE Shroud Repair recently installed on Hatch Unit 1. Georgia Power Company has submitted a response to those ' questions.
1 RT.0998.G/kew
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