ML17331A598
| ML17331A598 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 01/27/1981 |
| From: | Dolan J INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| AEP:NRC:00268C, AEP:NRC:268C, NUDOCS 8102020372 | |
| Download: ML17331A598 (5) | |
Text
A'r REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIOS)
ACCESSION NBR R 8 1 0202037?
DOC ~ DATEj 8 1/0 1 /27 NOTARIZED:
NO DOCKET ¹ FACIL:50 315 Donald C ~
Cook Nuclear Power Pl anti Unit 1 i Indi ana K
0 50 "316 Dona 1 a C ~
Cook Nuc1 ear Power P
1 ant E Unit 2E Indi ana C
050003 1
AUTH,'NAME
'AUTHOR AF FlLIATION DOI ANE J ~ E ~
Indiana 8
Hi chi gan Electric Co ~
REC IP ~ NAME RECIPIENT AFFILIATION DENTONR H ~ R ~
Office of Nuclear Reactor Regul ationi Director
SUBJECT:
Forwards info r eauested re gr i d degraded vol tage for operat i on of 69 k V al ternate o ffsi te power source transf ormer< per 800b28 1 tr ~
DISTRIBUTION CODE:
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TITLE: Onsi te Emergency Power Systems NOTES: IS,E:3 copies al 1
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INDIANA IIt MICHIGAN ELECTRIC COMPANY P. O.
BOX 18 BOWLING GR E EN STATION HEW YORK, N. Y. 10004 January 27, 1981 AEP:NRC:00268C Donald C.
Cook Nuclear Plant Unit Nos.
1 and 2
Docket Nos.
50-315 and 50-316 License Nos.
DPR-58 and DPR-74 Grid Degraded Voltage Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.
C.
20555
Dear Mr. Denton:
The attachment to this letter contains the information requested, by members of your staff concerning grid degraded voltage and supplements our.=letter of May 28, 1980 (AEP:NRC:002688) for operation of the 69 kV alternate offsite power source.
Very truly yours, ohn E. Dolan Vice President cc:
R.
C. Callen G. Charnoff
. R.
S.
Hunter.
R.
W. Jurgensen D. V. Shaller - Bridgman Region III Resident Inspector at Cook Plant - Bridgman goiS.
5
/~
sioaoso
ATTACHMENT TO AEP:NRC:00268C The voltage taps on the 69/4 kV alternate offsite power source trans-former 1-EP and its standby 2-EP were changed from Tap 4 (67.0/4 kV) to Tap 3 (68.8/4 kV) on July 21, 1980:
This tap change resulted from the initial evaluations of the alternate offsite power source as cormitted to in our letter of Oecember 17,
- 1979, No. AEP:NRC:00268.
The loading limitations of the 69 kV alternate offsite power source were reviewed utilizing worst case conditions."
The previously submitted analysis resu'its reviewed the application of 2 safety trains of one unit under accident conditions to transformer 1-EP.
The previously submitted results were satisfactory for meeting the minimum requirements.
- However, due to the NRC requirement that we impose technical specification limitations on the loading of the 69/4 kV transformer (1-EP),
we have reanalyzed the 69 kV alternate offsite power source to justify our proposed Technical Specification for loading 'the transformer based on measured bus voltage 905 I'
~tile b
Additional studies of the alternate offsite power source were conducted to evaluate its performance under more severe loading conditions.
Cases C4 and C5 of the Attachment to our letter AEP:NRC:0268, where both safety trains of one unit under accident conditions, and one safety train of the opposite unit under shutdown conditions are connected to transformer 1-EP were studied.
Case C4 evaluated the steady state conditions and C5 evaluated the voltage conditions during the starting of the last and largest motor.
The results are tabulated below:
Case C4 Source TR.EP-1 Bus T11A T11B Tl 1 c
'T110 T21A T21B Base Vol ta e
4 kV Per Unit V~olta e
- 0. 97 llA 118 11C 110 21A 21B 575 V
0.95 C5 TR. EP-1 Tl lA T11B Tl lc T 1'10 T21A T210 4 kv 0'4
Case Source Bus 11A 11B 11C 110 21A 218 Base Yolta e 575 Y
Per Unit
~Volta e
0.92 The results of the above studies made during the lowest anticipated 69 kV voltage conditions demonstrate that 3 safety trains can be connected to the alternate offsite power source without degrading the bus voltages to an unacceptable level under steady state conditions as indicated in Case C4 or during worst case motor starting conditions as indicated in Case C5.
The voltage study supports the loading limitation of > 905 rated voltage previously submitted in our proposed Technical Specification with 3 safety trains connected to the 69 kV alternate offsite power source under worst case voltage conditions.
lie suggest that the proposed Technical Specifica-tion be re-worded in such a manner as to administratively limit the loading of the alternate offsite power source in such a manner as to maintain at least 90% of rated voltage under steady state conditions but not to exceed the safety bus loading corresponding to any 3 safety trains.