ML20044E699
| ML20044E699 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 05/05/1993 |
| From: | Terry C NIAGARA MOHAWK POWER CORP. |
| To: | Ruland W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NMP88361, NUDOCS 9305250329 | |
| Download: ML20044E699 (2) | |
Text
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Y NIAGARA N.UMOHAWK NINE MILE POINT NUCLEAR STATION /P.o. BOX 32 LYCOMiNG. NEW YORK 13093 / TELEPHONE (315) 343-2110 May 5,1993 NMP88361 U. S. Nuclear Regulatory Commission Region I Attn: William Ruland 475 Allendale Road King of Prussia, PA 19406
Reference:
Nine Mile Point Unit 1 Docket No. 50-220 DPR-63
Dear Mr. Ruland:
The purpose of this correspondence is to summarize the discussion on April 5,1993, between yc,u and members of my staff, regarding the status of a commitment for unresolved item 50/220 91-30-015 from the Nine Mile Point Unit 1 Electrical Distribution System Functional Inspection (EDSFI). This commitment was to complete an analysis to determine the adequacy of degraded bus voltage setpoints and to implement any changes necessary prior to startup from the 1993 refuel outage (RFO12), as contained in Niagara Mohawk Power Corporation letter hWP1LO643, dated February 18,1992. Analysis of the degraded bus voltage was completed as committed; however, as a result of the analysis, the need for a Technical Specification (TS) Amendment was identified. Submittal of an amendment is not expected for several months and setpoint changes cannot be made until after NRC approval. We agreed to continue administrative controls on the degraded bus voltage as necessary.
You had severr.1 questions concerning the margin that was available in the administrative limits that have been imposed on the grid voltage since the time of the EDSFI. In response to those
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questiens, we indicated that our administrative controls implemented during EDSFI have been eficctive in maintaining grid voltage above the minimum allowable value of Il5kv. This administrative limit provides sufficient margin to assure adequate voltage is available to all safety related equipmeat. Average grid voltage at Nine Mile Unit 1 over a three year period, ending w
November 1992, is approximately 119kv. During the period following EDSFI(November 1991 through November 1992) the lowest recorded grid voltage was a single reading of 115.7kv. A load flow study completed in response to the above commitment, shows the most limiting componeni to be operable down to 113.6kv under maximum loading conditions. Therefore, we proposed to continue the use of administrative controls.
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s Mr. William Ruland a
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. Page 2 May 5,1993 It is our understanding that you are in agreement with the condnued use of these administrative i
limits on the 115kv grid, considering we have had no problem maintaining control of he system
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t under these limits, and the limit provides adequate safety margin.
Should you have any questions that concern this matter, please contact Mr. Alex Pinter of our Licensing Group at (315) 349-4621.
Very trul yours,
/
I l
C. D. Terry Vice President Nuclear Engineering NN.dgo pc:
Mr. T. T. Martin, Regional Administrator, Region I Mr. W. L. Schmidt, Senior Resident Inspector Mr. D. S. Brinkman, Senior Project Manager, NRR Mr. R. A. Capra, Director, Project Directorate I-1, NRR Records Management