ML19340D173
| ML19340D173 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 12/19/1980 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8012290247 | |
| Download: ML19340D173 (1) | |
Text
m _
I N Commonwrith Edis:n O ) One Drst Nabonal Plaza. Chicago. Ithnois O
Address Repli to ' Post Olkce Box 767 Chicago, Illinois 60690 December 19, 1980 1
Mr. Harold R. Denton, Director Of fice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 4
]
Subject:
Zion Station Units 1 and'2 Additional Information on Station Electric Distribution System Voltages r
NRC Docket Nos. 50-295 and 50-304 References (a):
May 2, 1980 letter from S.
A.
Varga to D. L.
Peoples 1
(b):
June 23, 1980 letter from W. F..Naughton to H.
R.
Denton i
Dear Mr. Denton:
l l
This is to provide additional information regarding Commonwealth Edison's response (reference b) to.NRC questions on i
adequacy of station electric distribution system voltages (reference c).
' of reference (b) indicates station electric distribution system voltages when the ESF bus of one unit is
.i operated from the second offsite power supply via a 4 kv bus J
crosstle.
This'is an unusual arrangement and is used only when at cold shutdown in accordance with plant operating procedures.
- Also, i
as noted on Attachment 3, start of-the 11,000 horsepower steam i
generator feedwater pump is not permitted in this configuration.
The low voltage condition (69.1%) on 480 volt bus 138 was therefore computed using'an excessively conservative set of acsumptions'and should not be considered to be a design basis. case.
1 Please-address-any further. questions to.my: office.
S One-(1 signed original and thirty-nine (39) copies of this ytransmitt'ahare)provided'foryouruse.
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Very truly yours,
} l( f.Adevn b
J:
T. R.
Tramm o
Nuclear-Licensing Administrator b
Pressurized Water Reactors
- cc:
Zion. Resident Inspector O
8909A 8 012290 g
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