ML080290386
| ML080290386 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 01/29/2008 |
| From: | Andrea Johnson Office of Nuclear Reactor Regulation |
| To: | Allen Hiser, Siva Lingam NRC |
| Lingam, Siva NRR/DORL 415-1564 | |
| References | |
| TAC MD6625, TAC MD6626 | |
| Download: ML080290386 (2) | |
Text
From:
Andrew Johnson To:
Allen Hiser; Siva Lingam Date:
1/29/2008 1:36:21 PM
Subject:
Re: NRC Question Regarding the VEGP MUR-PU Licensing Report (TAC Nos. MD6625 and MD6626)
- Siva, I concur. I will provide SE ASAP.
- regards, Andy Johnson
>>> Siva Lingam 1/29/2008 12:57 PM >>>
Per our telephone conversation with the licensee and Westinghouse (representing the licensee), the licensee in the below e-mail states that the critical cross sectional area of the tube-tubesheet welds in the steam generators at Vogtle Unit 1 (including SG 4 that experienced loose parts) has been analyzed and shown to be in compliance with the ASME Code at the MUR-PU conditions. Please review the licensee's e-mail, and provide your comments/concurrence/SE. After you are satisfied with the licensee's explanation, I will then docket the e-mail in ADAMS. Please respond.
>>> "Graham, D. Rick" < DORGRAHA@southernco.com > 1/29/2008 12:27 PM >>>
- Siva, A telephone conference between SNC, Westinghouse, and the NRC was held Monday, January 28, 2008, regarding the NRC question on the Unit 1 SG 4 loose part discussion that is contained in the Section 6.6.11 of the VEGP MUR-PU Licensing Report. Below is the SNC response:
The loose part occurred in VEGP Unit 1, not Unit 2.
The entire underside of the tubesheet in the hot leg side of SG 4 in Unit 1 was visually inspected using high resolution video viewing and recording techniques after the loose part was detected in 1996. The conclusion of the visual examination and tape review was that the amount of material present at the tube to tubesheet welds for all tubes was greater than or equal that that modeled in the original design analysis used to demonstrate compliance with ASME Code requirements. It should be noted that the actual weld shape and critical cross sectional area are significantly larger than that modeled in the structural analysis.
For defense in depth, an analysis of the structural integrity assuming a degraded tube to tubesheet weld was performed to demonstrate that the interface contact between the tube/tubesheet is sufficient to retain the tube in the tubesheet and prevent significant leakage even assuming no tube to tubesheet weld. This structural integrity analysis is not needed to support implementation of the MUR-PU at Vogtle Unit 1.
As discussed above, the critical cross sectional area of the tube-tubesheet welds in the steam generators at Vogtle Unit 1 (including SG 4) has been analyzed and shown to be in compliance with the ASME Code at the MUR-PU conditions.
There were no other SNC regulatory commitments.
- Thanks, Rick Graham Senior Engineer Southern Nuclear Operating Company Nuclear Licensing *Bin B048
- (205) 992-5808 * (205) 992-7885 CC:
Melanie Wong Mail Envelope Properties (479F721B.896 : 18 : 9144)
Subject:
Re: NRC Question Regarding the VEGP MUR-PU Licensing Report (TAC Nos. MD6625 and MD6626)
Creation Date 1/29/2008 1:36:11 PM From:
Andrew Johnson Created By:
ABJ1@nrc.gov Recipients nrc.gov EBGWPO01.HQGWDO01 MCW CC (Melanie Wong) nrc.gov OWGWPO04.HQGWDO01 ALH1 (Allen Hiser) nrc.gov TWGWPO01.HQGWDO01 SPL (Siva Lingam)
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