ML20073R516
| ML20073R516 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 04/28/1983 |
| From: | Tucker H DUKE POWER CO. |
| To: | Harold Denton, Novak T NRC, Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8305040273 | |
| Download: ML20073R516 (2) | |
Text
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s s DUKE POWER GoxPm P.O. nox 33180 CHAH1XYTTE, N.C. 28242 HALH. TUCKER TE I.E PIION E
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April 28, 1983 N H"~*"
Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
T. H. Novak Re: McGuire Nuclear Station Docket Nos. 50-369, 50-370 This letter is provided to clarify information related to reactor trip breakers (RTB) as reported in our letters of February 28, 1983, March 1, 1983, and March 22, 1983. The following information was provided:
The February 28, 1983 letter stated that no RTB failures had occurred.
The March 1, 1983 letter corrected the previous letter by stating that a failure of one Unit 2 RTB to trip had occurred during preoperational testing of the Reactor Protection System (RPS). The March 22, 1983 letter in response to IE Bulletin 83-04 stated that failure of one Unit 2 RTB occurred on five occasions in early 1983.
In responding to an NRC staff request oa February 28, 1983 related to the Unit 2 license review, a quick review was performed by station personnel and no RTB failures were identified or documented. On February 28, 1983 after the letter was submitted, an individual remembered that a failure may have occurred during pre-operational testing of the RPS on Unit 2.
At the time of the event, whether a failure had actually occurred was not clear. This is due to the fact that no problems were found with the RTB when investigated by maintenance personnel on February 18, 1983. Nevertheless, the event was reported in the March 1, 1983 MMl letter as a potential failure.
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Accurate details of the apparent failure were not documented as a test discrepancy because the specific test was not intended to verify RTB operation and, therefore, j,h the failure did not involve a failure to meet the test acceptance criteria. A h work request for repair was initiated, but as stated previously, no further problems p
were found. Because of the lack of documentation of the event, recollection by g, ged station personnel was necessary to identify the event. Please note that the event 8 N j was not reportable to the NRC under Technical Specifications because Unit 2 did not l hold an operating license.. Also, reportability under 10 CFR 50.55(e) was not g.S'.iLNIrequired because there was no reason to suspect a design or construction deficiency.
The March 22, 1983 letter stated that RIB failure had occurred on five occasions in early 1983. This apparent discrepancy is attributable to the fact that different 8305040273 830428 PDR ADOCK 05000369 S
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Harold R. Denton April 28, 1983 Page 2 persons describing their recollection of the event used different definitions of
" failures". For example, failure to trip upon five consecutive attempts was con-sidered to be five failures.
Investigation of subsequent failures has shown that once a failure to trip via the undervoltage (UV) attachment has occurred, further attempts to trip the RTB by the UV attachment will not execute until the RTB is tripped via the shunt coil attachment, thus freeing the UV attachment. Therefore, the five consecutive failures to trip the RTB are considered to be a single failure.
We apologize for any inconvenience caused by the differences in the aforementioned letters.
Very truly yours, C c(/$ ?
al B. Tucker REH:j fw cc:
Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia Mr. W. T. Orders NRC Resident Inspector McGuire Nuclear Station e*--vWe'w-se se*-e e te
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