NL-08-0350, Core Shroud Stabilizer Assembly Update
| ML080670429 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/07/2008 |
| From: | David Jones Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-08-0350 | |
| Download: ML080670429 (2) | |
Text
David H. Jones Southern Nuclear Vice President Operating Company, Inc.
Engineering 40 Invemess Center Parkway Birmingham, Alabama 35242 Tel 205.992.5984 Fax 205.992.0341 SOUTHERNA COMPANY March 7, 2008 Energy to Serve.tOurWorM'"
Docket No.:
50-321 NL-08-0350 U. S. Nuclear Regulatory Commission ATrN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant Core Shroud Stabilizer Assembly Update Ladies and Gentlemen:
In Southern Nuclear Operating Company (SNC) letter NL-07-1155 dated August 14, 2007 SNC requested NRC approval of a proposed modification to each of the four core shroud stabilizer assemblies. In that letter, SNC proposed to replace the Hatch Unit 1 stabilizer assembly upper supports and tie rod top nuts during the 2008 Refueling Outage (1 RF023).
During the 2008 refueling outage (1 RF023), the upper support brackets were replaced at locations 135' and 315'. Although plans called for the upper support brackets at all four locations (45', 135',225', and 315') to be replaced, the upper bracket at location 225' could not be replaced during 1RF023 and it was decided to defer replacement of the symmetric upper support bracket at 45' as well. The 45' and 225' brackets were reexamined using IWI and the results documented.
Evaluation of the inspection results of the 225' bracket demonstrates that the bracket does not pose a hazard during the next operating cycle of the Unit 1 reactor. No anomalies were observed on the 45' bracket.
Because analysis of the UT examination of the Plant Hatch Unit 1 shroud horizontal welds has demonstrated that the original design function is maintained and there is adequate structural margin for the next cycle of operation without crediting the repair hardware, SNC requests that completion of the installation of the modified core shroud stabilizer assemblies described in the August 14, 2007 letter be extended until the 2010 refueling outage (1RF024).
- u. S. Nuclear Regulatory Commission NL-08-0350 Page 2 This letter contains no NRC commitments. If you have any questions, please advise Mr. Ray D. Baker at 205-992-7367.
D. H. J es Vice President - Engineering DHJ/PAH/daj cc: Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. D. R. Madison, Vice President - Hatch RTYPE: CHA02.004 U. S. Nuclear Regulatory Commission Mr. V. M. McCree, Acting Regional Administrator Mr. R. E. Martin, NRR Project Manager - Hatch Mr. J. A. Hickey, Senior Resident Inspector - Hatch