ML20058B382
| ML20058B382 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 10/23/1990 |
| From: | Hairston W GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-88-009, IEB-88-9, MSV-00344, MSV-344, NUDOCS 9010300159 | |
| Download: ML20058B382 (3) | |
Text
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l L Georo a Power Company I.
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333 Pedmont Aenue Ananta. Georg a 30300 -
f Telephone 404 526-3195 j Maang Address.
40 lnvernens Center Parkway Post Offce Box 1NS 4""3"Me"71" October 23, 1990
, m g.,,n y -,, m f,
r W. o, Hairston, til Senior Veo Preudent NsJear Opereons.
M$y.QQ344
- 1153 i
t Docket Nos. 50-425
)
U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C.
20555 j.
Gentlemen:
V0GTLE ELECTRIC GENERATING PLANT RESPONSE TO NRC BULLETIN 88-09 j
L Nuclear Re ulatory Commission (NRC)Bulletin 88-09 which concerns thimble tube thinn ng in Westinghouse reactors requires submittal of a written response that (a) confirms that an inspection program consistent with that requested in Action Item I of the Bulletin has been established and (b) n nfirms that inspections'of the thimble tubes have been performed and that
- appropriate corrective actions were taken.
The Bulletin requests that a written ~' response be submitted within 30 days of completion of the thimble
. tube inspections.
Thimble tube inspections as required by NRC Bulletin 88-09 were completed-
~for Vogtle Electric Generating Plant, Unit 2. (VEGP-2) on September 27,-
1990,: during the unit's first maintenance / refueling. outage.
Eddy current
,testingy was performed on each of the thimble tubes by Westinghouse. Th'e results.of the inspection indicate that twelve (12) out of' fifty-eight (58)
' tubes have some degree of wall-less due to external wear.
The indicated
- wall loss ranged.from a minimum of eighteen percent -(18%)- for one thimble a
to a maximum of thirty-four percent- (34%) for one-- thimble.
. estinghouse W
has indicated that the allowable wall loss criteria is' sixty percent (60%)
of wall thickness.-
The < Westinghouse -evaluation of~'the VEGP.-2 data concluded that each of the affected thimble tubes were-found to be acceptable for continued operation without any: corrective action required
.at this time.
~ Predictions were made by. Westinghouse regarding 'the anticipated wall loss C
which could: exist by the end of the next eighteen month toerating cycle if no corrective action was taken.
Based on the Westinghouse predictions,
- none-of the-affected twelve thimble tubes are expected to wear-beybnd the-sixty percent (60%) maximum wall loss acceptance criteria be.%re the end of the next eighteen month operating ~ cycle.
Accordingly, no corrective
- action, e.g., repositioning of tubes, is required at this time.
It should
-be. noted that Westinghouse no longer adds ten percent (10%) to the eddy current-indicated wall. loss as a result of a Westinghouse Owner's Group E8A28a8488a8%$'
T61f.
O PDC g.
/
U. S. Nuclear Regulatory Commission MSV-00344 Page 2 program on thimble wear. Worn thimbles were precisely measured in a Hot Cell and the results were then compared to eddy current inspection performed on the same tubes.
Westinghouse has indicated that in all cases, the eddy current inspection results were either the same as the measurements, or in most cases, greater than the actual measurements.
Since thimble tube thinning was observed by this inspection, the thimble tubes will be reinspected during the next VEGP-2 maintenance / refueling
-outage.
Once this second inspection is performed, it will be possible to refine the wall loss predictions for future cycles and therefore determine whether inspection during each future VEGP-2 maintenance / refueling outage will be warranted.
Submittal. of the VEGP-2 thimble tube inspection results for the unit's first maintenance / refueling outage completes the reporting requirements associated with NRC Bulletin 88-09 relative to the Vogtle Electric Generating Plant.
Inspection results for the eddy current inspection of the thimble tubes at Vogtle Electric Generating Plant, Unit I during its first maintenance / refueling outage were submitted previously by Georgia Power Company letter ELV-00063 dated December 7, 1988.
Mr.- W. G.
Hairston, III states that he is a Senior Vice President of Georgia Power Company and is authorized to execute this oath on bahalf of Georgia Power Company and that, to the best of his knowledge and belief, the facts set forth in this letter are true.
Georgia Power Company By: /t.)I. 4/,3.,Y r
/
W. G. Hairston, III.
Sworn to and subscribed before me this JZ3 day of October, 1990.
I JfAtwA nl:14ff Notary Public WGH,III/JAE/gb -
L
4 U. S. Nuclear Regulatory Commission M',V-00344 Page 3 xc:
Georoia Power Company Mr. C. K. McCoy Mr. W. B. Shi) man Mr. P. D. Rus1 ton Mr. J. A. Bailey Mr. L. A. Ward Mr. R. M. Odom NORMS U. S. Nuclear Reaulatory Commission Mr. S. D. Ebneter, Regional Administrator Mr. D. S. Hood, Licensing Project Manager, NRR Mr. B. R. Bonser, Senior Resident inspector, Vogtle
.