ML20205G129
| ML20205G129 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 03/05/1987 |
| From: | Rhodes F WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| Shared Package | |
| ML20205G104 | List: |
| References | |
| 87-0041, 87-41, NUDOCS 8703310379 | |
| Download: ML20205G129 (2) | |
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M NUCLEAR OPERATING CORPORATION March 5, 1987 Mr. Eric Johnson, Director Division of Reactor Safety & Projects U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 Letter: NO 87-0041
Dear Mr. Johnson:
In response to telephone discussions with your staff on March 4, 1987, we are providing the following additional information concerning Inspection Report 50-482/87-05 and the Surveillance Procedure STS RE-011, Revision 1, "RCS Total Flow Rate Measurement", which was performed on January 14, 1987.
The precision heat balance was performed on January 14, with the indicated RCS flow reading an average of 99%. From the previous precision heat balance, the Technical Specification limit would correspond to 975. Thus, when preliminary calculations indicated an RCS flow of 391,287 GPM (equivalent of 96.4%), these results were not believed because of the indicated flow indication being clearly above the LCO limit.
A On January 15, 1987, the precision heat balance was resumed with similar results. The data was still considered invalid. The evaluation process as to why the low result included:
Consideration of reduced power levels and possible non linearities in instrumentation Evaluation of potential calorimetric errors Evaluation of loose parts monitor and core exit thermocouples for evidence of real problems Evaluation of reactor coclant pump performance All the while however, recognizing the RCS flow indication was being relied on to meet the Technical Specification.
8703310379 870305 DR ADOCK 05000482 PDR
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h P.O. Box 411/ Burfington, KS 66839 / Phone: (316) 364-8831 An Equal opportunity Empoyer M F.tCVET
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NO 87-0041 Page 2 These reviews by I&C, Results Engineering, and Reactor Engineering were thorough, detailed, and required time to complete. This, coupled with plant conditions limiting plant power levels, delayed the final results. However, these efforts provided assurance on a daily basis that the decision to remain at power was within Technical Specification limits. In all, 3 Reactor Engineers, 1 Results Engineer, 8-12 I&C Technicians representing 2 crews, and 2 I&C Engineers were working almost full time to resolve or prove our surveillances. Subsequently, 2-3 NPE Engineers with 2 KG&E Corporate Relay personnel performed analysis and electrical testing to verify RCP motor and speed performance. Supervisory and Management personnel were involved as new data was obtained.
In addition to these efforts, z
Westinghouse was contacted and provided with whatever data was requested.
Conference calls with Westinghouse and several other Nuclear Stations were conducted to provide options and inquire if similar problems were occurring at other sites.
On January 20, 1987, the plant had achieved 1005 power and a precision heat balance was performed. Since the 7 day window for instrument calibration had been exceeded, the results could not be official, however, the calibrated flow rate was 393,591 GPM, which would satisfy the Technical Specification. The results were still considered questionable, however due to the disparity with flow indication and the ongoing investigation as discussed above.
On February 4,1987, after resolution of problems with feedwater flow indication, and again after resumption of full power operation, a precision heat balance performed to evaluate the impact of these corrections, and RCS flow was calculated to be 395,473 GPM. On February 5, 1987, the required calibrations were completed and the precision heat balance surveillance test was performed. The RCS flow rate was determined to be 395,792 GPM. While our evaluation of this deviation is not complete, we are comfortable that
'E this establishes a lower bound on RCS flow.
It is important to remember that during this evaluative process, we had RCS flow indication which, while indicating some apparent flow reduction, also provided clear indication of compliance with the LCO.
Sincerely, Forrest T. Rhodes Vice President Nuclear Operations FTR/aew cc: RMS
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