ML19209C488
| ML19209C488 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/25/1979 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| TASK-07-03, TASK-08-01.A, TASK-RR NUDOCS 7910150653 | |
| Download: ML19209C488 (3) | |
Text
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UNITED STATES y
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WASHINGTON, D. C. 20555 S
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September 25, 1979 Docket No. 50-245 Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Northeast Nuclear Energy Company Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
RE: MILLSTONE NUCLEAR POWER STATION, UNIT NO. 1 We are currently reviewing the adequacy of the offsite power systems of nuclear power plants and in particular, the loss of offsite power events at your facility. One aspect of this review concerns the history of experienced total and partial power outages and attendent voltage or frequency conditions of the grid.
In our review of this matter we have drawn upon the infomation provided to us via Licensee Event P,eports and followup letters which you have sent to us. Our review of these reports indicated the loss of offsite power events have accurred at Millstone Nuclear Power Station June 25, 1971 and April 7,1976. To complete our review of loss of offsite power events we require the additional information concerning the station offsite grid indicated in the enclosure to this letter.
Please provide your response to the attached questicns for the Millstone Nuclear Power Station within 90 days of receipt of this letter.
Sincerely, C/ wp f fw.w
'g Dennis L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors
Enclosure:
Request for Additional Infomation cc w/ enclosure:
l l } /j 3 j g See next page l$
7 910150 b P
Mr. W. G. Counsil September 25, 1979 cc William H. Cuddy, Esquire Day, Berry & Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Anthony Z. Roisman Natural Resources Defense Council 917 15th Street, N. W.
Washington, D. C.
20005 Northeast Nuclear Energy Company ATTN:
Superintendent Millstone Plant P. O. Box 128 Waterford, Connecticut 06385 Mr. James R. Himmelwright Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Nuclear Regulatory Conmission, Region I Office of Inspection and Enforcement ATTN: John T. Shedlosky 631 Park Avenue King of Prussia, Pennsylvania 19406 Waterford Public Library Rope Ferry Road, Route 156 Waterford, Connecticut 06385 1134 340 i
ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION LOSS OF 0FFSITE POWER A.
For losses of offsite power where less than all offsite power was lost:
1.
How many circuit's to the offsite network are normally available and how many were lost during the event?
2.
What was the cause of the event?
3.
Why did the other lines not fail when some did fail?
4.
Was any voltage increase or decrease experienced just prior to or during the outage? If so, please give details, voltages reached, affects, etc.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
6.
How long was power unavailable from the circuit?
7.
Date of Event.
B.
For losses.of all offsite power:
1.
How long was the power off? How long for partial recovery?
Please give details.
2.
If turbine trip occurred, how soon after did loss of offsite power occur?
3.
If pcwer was recovered promptly (10 minutes or less), was it due to automatic or manual actions?
4.
Was any voltage increase or decrease experienced just prior to or during the outage?
If so, please give details, voltages reached, affects, etc.
5.
Was any frequency decay experienced just prior to or during the outage?
If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc.
6.
Date of Event.
C.
Were there any other icss of offsite power events cther than we have listed.?
If so, please give details of each event.
I134 341