ML20137J238
| ML20137J238 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 01/15/1986 |
| From: | Gucwa L GEORGIA POWER CO. |
| To: | Muller D Office of Nuclear Reactor Regulation |
| References | |
| 0237C, 237C, SL-180, NUDOCS 8601220336 | |
| Download: ML20137J238 (2) | |
Text
Georg a Power Compar:y 333 Ptearnont Avenue Atlanta. Georg a 30308 Temphone 404 526-6526 MaMg Address Post Of f.ce Box 4545 Atianta. Georg a 30302 h
Georgia Power L T. Gucwa
- eS-v" e ec S We'n Ma ager Nuclear Eng reer og and Ch.ef Nocfear Eng reer SL-180 0237C
~
January 15, 1986 Director of Nuclear Reactor R3gulation Attention: Mr. D. Muller, Project Director 4
BWR Project Directorate No. 2 Division of Boiling Water Reactor Licensing U. S. Nuclear Regulatory Commission Washington, D. C.
20555 NRC DOCKETS 50-321, 50-366 OPERATING LICENSES DPR-57, NPF-5 EDWIN I. HATCH NUCLEAR PLANT UNITS 1, 2 PLANT HATCH TURBINE INSPECTIONS Gentlemen:
Recent turbine inspections at Plant Hatch have revealed information which may be of interest to the NRC.
The information presented herein is preliminary and an evaluation of the inspection results is underway. This letter provides the status of inspection results and conclusions to date.
Unit I:
Low pressure (LP) turbines "A" and "B" are being inspected during the current refueling outage which started on November 27, 1985.
Cracks have been found in the dovetail area between pin holes which are used for attaching the buckets to the wheel. Other cracks have been found in the keyway area of the rotor. The following table summarizes findings to date:
"A" LP ROTOR Stage Condition L-0, both ends Cracking in dovetail area L-1, both ends Shroud lifting L-2, both ends Keyway cracking L-3, generator end Keyway cracking L-4, generator end Keyway cracking CAN 8601220336 860115 A
%F, PDR ADOCM 05000321 G
PDR 1
1 4
GeorgiaPower h(
Director of Nuclear Reactor Regulation Attention: Mr. D. Muller, Project Director BWR Project Directorate No. 2 January 15, 1986 "B"
LP ROTOR Stage Condition L-0, both ends Cracking in dovetail area L-2, both ends Keyway cracking L-3, both ends Keyway cracking L-4, both ends Keyway cracking Cause of the cracking is under investigation. Water induction is not believed to be a cause. Material or fabrication problems are being considered. Resonant torsional oscillation of the turbine rotor induced by adverse generator load characteristics is also considered a possible cause.
Unit _21 The unit was shutdown on December 25, 1985 for a maintenance outage to repair steam leaks and to inspect the LP turbine last stage wheels for problems similar to those found or, Unit 1.
No significant problems were noted, and the unit was returned to service on December 29.
Please contact this office if you have any questions or comments.
Very truly yours, WY&w L.T. Gucwa PLSpringer/lc c: Mr. J. T. Beckham, Jr.
Mr. H. C. Nix, Jr.
Dr. J. N. Grace (NRC-Region II)
Senior Resident Inspector GO-NORMS rwns