ML20039D993
| ML20039D993 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 12/29/1981 |
| From: | Parker W DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8201060411 | |
| Download: ML20039D993 (2) | |
Text
i DUKE POWEH COMPANT Powsa Durtotxo 422 SocTu Cncacu STanET, CIIAHl.OTTE, N. C. ana4a WILLIAM O. PAR K ER.J R.
December 29, 1981 wcr Potsicru, TtttPwont:AntA 704 g
Srtase PacDuctron 373-4083
/
RECELVED Mr. Harold R. Denton, Director
~
Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission JAN 5 1982>
Washington, D. C.
20555 i auttasanuar seus fg getszw assa9t a DQC Attention:
Ms. E. G. Adensam, Chief f
Licensing Branch No. 4 to to Re: McGuire Nuclear Station Docket No. 50-369
Dear Mr. Denton:
On October 31, 1981 Duke Power Company notified the NRC Staff of tube degradation on a non-domestic Westinghouse plant with Model D_ steam generators similar to those at McGuire Nuclear Station. Subsequently a meeting was held on November 20, 1981 in Bethesda to brief the Staff on the details of the problem as well as Duke Power Company's plans for operation of McGuire. In particular Mr. H. B. Tucker. outlined a planned sequence of plant operation, steam generator tube inspection and instru-mentation installation. The purpose of this letter is to update the NRC Staff on the status of this effort to date and on plans for future operation.
Eddy current testing was performed on the 'A' Steam Generator to determine if a threshold power level existed at which tube vibration in the preheater was initia-ted.
Rows 49, 48 and 47 were examined. This testing was conducted after two weeks operation at approximately 50% power and again after one week operation at 75% power.
This testing was conducted by Babcock and Wilcox Company personnel utilizing a.590" diameter differential probe. A Zetec MIZ-12 multi-frequency apparatus was employed at frequencies of 130 khz, 200 khz, 400 khz and 550 khz. Since this examination was looking for wear damage at tube support plate locations both 130-550 khz and 200-400 khz mixed outputs were used to eliminate the support plate signal leaving only defect signals for analysis. An ASME Section XI type calibration standard was used.
Results of both of these inspections (i.e. after operation at 50% and 75% power) were reviewed by Babcock and Wilcox, Duke Power Company, Westinghouse and EPRI NDT personnel. A comparison with the results of the preservice inspection was made.
No wear type indications were observed.
'During the November outage, three transducers were mounted around the feedwater nozzle on each steam generator. These transducers are intended to provide an early indication of any gross mechanical vibration inside the preheater and will eventually be used in conjunction with the internal instrumentation when installed. To date no signals have been noted which correlate to preheater/ tube vibration. Resonance peaks which have been observed were caused by flow turbulence rather than any mechanical vibration phenomenon.
Ohhh fl
~
2
.u.
i Mr.' Harold R. Denton December 29,>1981
~
Page 2 Currently, the unit is in the startup phase. Plans are to increase ~ power to 90%,
hold at that level for up to 4 days then increase to 100% for one day.: Power opera-
~ ion would then continue for up to 6 weeks:at power levels up to approximately-75%.
t The-unit will then be shutdown, eddy current examination performed on all-4 steam generators and internal. instrumentation mounted in one steam generator as described in our November 20, 1981 meeting in Bethesda. This operating plan represents our best efforts to balance testing and operational needs with a prudent course'of action to assure the integrity.of the steam generators. Minor changes to this planned sequ-ence may occur due to unf9rseen circumstances; however, we will keep you advised of any significant departure.from this plan.
Please advise if u have any questions.regarding this matter.
V truly yours,
- ().,
m..
William O. Parker, J GAC/jfw
'cc:
Mr. P. R. Bemis Mr. James P. O'Reilly, Regional Administrator.
Senior Resident Inspector U. S.. Nuclear Regulatory Commission
.McGuire Nuclear Station Region II 101 Marietta Street,. Suite 3100 Atlanta, Ceorgia-30303 t
.