ML19260D353
| ML19260D353 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/01/1980 |
| From: | Janecek R COMMONWEALTH EDISON CO. |
| To: | Gammill W Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19260D354 | List: |
| References | |
| NUDOCS 8002080530 | |
| Download: ML19260D353 (3) | |
Text
e-Commonwealth Edison O
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j 7 _ g' One_ First NM.cnal f ara,Ch< lao Ismo's
- kvl, Address Rep:y to Post Othce Box 7F
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Chicago, lihnois C0690
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a l'ebruary 1, 1980 Mr. William Gammill, Acting Assistant Director for Operating Reactor Projects Division of Operating Reactors U.S.
Nuclear Regulatory Commiscion Washington, DC 20555
Subject:
Drenden Station Unit 1 Adequia:y of S t at ion 1;l ect I ic Dint ribut ion Syntem Voltage >
NRC Dochet No.
50-1_0_
References (a):
W.
P.
Gammil] letter to All l' owe r Re a c t.o r 1,icenseen dated Augunt. 8, 1979 (b) :
R.
I'.
Janecek lot ter to W. Gammill.
dated November 1,
1979
Dear Mr. Gammill:
In accordance wit h R.
esences ( ci ) and (b), Common-wealth 1:dison Co. hac revicwed the adc.quacy of the 1)re ; den Unit 1 auxiliary power cynt em.
The attachment to this letter containt a report which addresscn the adequacy of the electric distribution system voltages and describen the results of our analysin of the auxiliary power system.
Please addreco any additional questions you may have concerning this matter to this office.
One (1) signed oi2qinal and thirty-nin (39) copies of this trannmit.ta] are-provided for your une.
Very truly yours, fi fGfo (fJ. f..me u2i u
Robert l'. Janecek Nuclear Licenning Administrator Boiling Water H e a c t.o r s Attachment 80020 o $ 3 a g
8
Attachment Adequacy of Station Electric Distribution System Voltages Commonwealth Edison Company Dresden Unit 1 February 1, 1980
Dresden Unit 1 The NRC has required the licensees of power reactors to show that each plant's station auxiliary power system will provide adequate power to essential loads. Specifically, the licensee is asked to confinn the acceptability of the voltage conditions on the station electric distribution systms with regard to:
1.
Potential overloading due to transfers of either safety or non-safety loads.
2.
Adequacy of the offsite and the onsite distribution system to automatically start as well as operate all required safety loads.
Dresden Statin Unit I has two possible sources of offsite power (see Figure 1 Attachment A). One is Reserve Auxiliary Transformer #12 (RAT-12) and the second is 34 KV Transfonner #13.
RAT-12 has the capacity to carry all the nonnal auxiliary power needs of Unit 1.
34 KV Transfonner 13 has the capacity to carry all essential auxiliary power loads on Unit 1 except for the new Unit i HPCI loads.
There are two separate and complete HPCI systms being installed for Unit 1.
Each HPCI system is driven from its own diesel generator set so that these loads are separated frm either RAT-12 cr 34 KV Transformer 13.
This plant modification is being reviewed as part of the Dresden Unit 1 backfit program.
Attachment A provides an analysis of the Dresden Station Unit 1 auxiliary power system voltages for RAT-12 assuming the transfonner is loaded w.ch the maxi-mum expected loading on the auxiliary power system, and for 34 KV Transformer 13 assuming the transfonner is loaded with the maximum expected essential loads con-nected to 480 volt substations 14, 16, 116 and 117.
Attachment B provides a review of the electric power system to the re-quirements of GDC-17.
As indicated in Attachment A, the perfonnance of the auxiliary power system at th? 4 KV and 480 volt levels is adequate provided that the taps on RAT-12 are cnanged to provide a 2h% boost (i.e.: present tap 138.00 KV is changed to new tap 134.55 KV). This tap change will be made before Dresden Unit 1 is returned to service in June 1981.
A test was perfonned at Zion Station to verify the results of the com-puter program used to analyze the auxiliary power voltages. The results of that test were reported in a letter to W. Gantnill from R.F. Janecek dated December 14, 1979. The same computer program was used to compute the Dresden 1 voltages as was used to compute the Zion voltages; therefore, we conclude that no further testing is necessary to verify the results of the Dresden Unit I voltage analysis.