ML19347E812
| ML19347E812 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 05/01/1981 |
| From: | Withers B PORTLAND GENERAL ELECTRIC CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-80-18, NUDOCS 8105130427 | |
| Download: ML19347E812 (3) | |
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May 1, 1981 1G gy
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Trojan Nuclear Plant
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Docket 50-344
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9 License NPF-1 Mr. R. H. Engelken, Director U. S. Nuclear Regulatory Ccomission Region V Walnut Creek Plaza, Suite 202 1990 N. California Blvd.
Walnut Creek, CA 94596
Dear Mr. Engelken:
As stated in PCE's response dated September 24, 1980 to IE Bulletin 80-18, flow verification tests were conduc.ed in December 1980 to determf.ne whether the Centrifugal Charging Pump (CCP) miniflow bypass systems are functioning as designed. Based on data taken during these tests and additional information from Westinghouse, PCE concluded that the CCP miniflow flow rates are in line with those assumed for the associated safety evaluation provided by Westinghouse, thus allowing impicmentation of the recommended interim modification.
The initial test results indicated that the potential existed for a low flow condition in the South (Train A) CCP miniflow line. Piping config-urations would not permit optimum placement of the flow instrument, and the instrument produced the low readings. This anomaly, when evaluated with other tcat data taken, data error analysis, and periodic operating test results, tended to lead to the conclusion that the South CCP miniflow system is functioning satisfactorily and is adequate to prevent damage to the pump. However, in order to fully assess the potential problem of inadequate pump cooling flow, PCE retested the South CCP miniflow system in March 1981 utilizing more reliable instrumentation.
In addition to recording flow data, the rise and stabilization of pump miniflow line and internal recirculation line temperatures were closely monitored. These results confirmed that the miniflow flow rate for the South CCP is probably slightly below the recommended minimum value of 60 gpm.
PCE concludes, however, that the South CCP miniflow system is operating satisfactorily, and the pump can be safely operated at these conditions.
This conclusion is based on the demonstrated stability of the recirculation line temperatures and comparisons to those observed for the North CCP, and the relatively small dif ference between the measured and recommended minimum flow.
In light of the current status of Westingheuse efforts to 810 513 0 g 12i sw m man em asi o, coon 97:o.
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Po:tland Gana:n! Elco':icCoapany Mr. R. H. Engelken May 1, 1981 Page two permanently resolve the issues of CCP deadheading and CCP pump shaf t fatigue cracking, we 1-lieve that continued operation is acceptable until final recommendationt m Westinghouse are received. Based on those recommendations, we w
. then determine whether actions to increase recirculation flow are warranted.
In the interim, we will continue to periodically conduct pump vibration tests in accordance with previous Westinghouse recommendations.
A summary of test is attached to this letter.
It should be noted that the results of this additional testing do not alter PGE's original response to IE Bulletin 80-18.
If you have any questions, please contact me.
Sincerely, L
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Bart D. Withers Vice President Nuclear Attachments c:
Mr. Lynn Frank, Director State of Oregon Department of Energy Director, Office of Inspection and Enforcement Division of Reactor Operations Inspection U. S. Nuclear Regulatory Commission 9
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c-Attachment R.11. Engicken Trojan Nuc1 car Plant May 1,1981 Docket 50-344 License NPF-1 DATA
SUMMARY
CCP MINIFLOW TESTS Table 1 December Flow Data
(.orrected)
Best Estimate Flow Range (Mean) Flow (gpm)
(gpm)
North single-pump operation:
61.6 - 72.7 67.1 North dual-pump operation:
62.7 - 74.0 68.3 South single pump operation:
60.2 - 71.0 65.6 South dual-pump operation:
52.7 - 62.0 57.4 Table 2 March Flow Data Best Estimate Standa.d Flow Range (Mean) Flow Deviacion (gpm)
(gpm)
(gpm)
South single pump operation:
58.9 - 60.7 59.8 0.59 South dual pump operation:
58.8 - 61.6 59.7 0.97 March Temperature Data (Steady-State)
Internal Recire Line Miniflow Line Temperature (*F)
Temperature (*F)
South single-pump operation:
116 118 North dual-pump operation:
NA 115 NOTE:
Temperature of miniflow lines while pumps are supply-ing normal charging to the RCS is 106*F + 2*F for single pump operation (pump flow rates of approximately 140-150 gpm).
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