ML20032A980
| ML20032A980 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 10/30/1981 |
| From: | Parker W DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8111040177 | |
| Download: ML20032A980 (2) | |
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Dunr Powsu COMPANY Powsu Bunmixo 422 Scurn Cuuncu Stanzr, CHAHLorTE, N. C 28242 WILLI AM O. PAR KER, J R.
Vice Patsiorut TELEPwont:AntA 704 sic.a emoouctio.
October 30, 1981 s734083 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.-C.
20555 Attention:
Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: McGuire Nuclear Station Docket Nos. 50-369, 50-3
Dear Mr. Denton:
The purpose of this letter is to inform you of the action that Duke Power intends to take following notification from Westinghouse of steam genera-tor experience on a Westinghouse non-domestic plant.
The steam generators are of sbnilar design to that in the McGuire Unit 1 plant.
A 3-loop unit was shutdown on October 21, 1981 due to primary to secondary leakage. The unit had been operating at power levels greater than 50% for a period of approximately five months.
Inspection of the Number 1 steam generator revealed a tube was leaking on the cold leg side of the steam generator within the preheater section.
Eddy current inspection is in progress. The data to date reveals numerous tubes with indications localized within the preheater section at baffle plate loca-tions. The tubes affected are peripherial in rows adjacent to the feed"ater inlet. The number of tubes with indications is cf the order of 100 per steam generator. The number of tubes with indications reported greater than 50%
of wall reduction are:
Steam Generator No. 1 - 21 Steam Generator No. 2 - 15 Steam Generator No. 3 - 10 Westinghouse believes these indications are due to excitation the steam gen-erator tubes from high fluid velocities and/or non-uniform _ vel
.ty distribution atd that reduction of flow velocity by reducing total feed flot should reduce the potential for vibration. Preliminary evaluations have been performed to determine the effects of continuing to operate the McGuire Steam Generators for the near term.
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8111040177 811030 h%E DR ADOCK 05000369 PDR
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Mr. Harold R. Denton October 30,.1981 Page 2
'A conservative evaluation of existing data indicates that operation for one month at 50% power is.not expected to cause unacceptable tube wall degrada-tion. Consequently, no potential safety problem is deemed to exist. McGuire is currently in the power ascension test program at 30% power and is scheduled to increase power _to 50% within the next few days..It is our intention to com.
plete the testing at the 50% plateau. This is expected to take approximately-two weeks. At that time we will evaluate the information available to deter-mine if further testing at higher power levels can be undertaken.
We will keep you advised as additional information becomes available..
Very truly yours, CJ $ k A f William O. Parker, 2-GAC/smh cc:
M. J. Graham Mr. James 7eilly, Director Residenr. Inspector U.S. Nucles A gulatory Comission McGuire Nuclear Station Region 11 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 I
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