ML19262A113
| ML19262A113 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/01/1979 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Mayer L NORTHERN STATES POWER CO. |
| References | |
| NUDOCS 7910260370 | |
| Download: ML19262A113 (3) | |
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UNITED STATES f y.j. e g
NUCLEAR REGULATORY COMMISSION
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OCT 1 1979 Docket Nos. 50-282 and 50-306 Mr. L. O. Mayer, Manager Nuclear Support Services Northern States Power Company 414 Nicollet Mall - 8th Floor Minneapolis, Minnesota 55401
Dear Mr. Mayer:
RE:
PRAIRIE ISLAND NUCLEAR GENERATING STATION, UNIT NOS. 1 AND 2 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 attendant degraded voltage er frequency conditions of the grid.
In our review of this matter we are drawing upon the information you provided in Licensee Event Reports (LERs) and followup letters to the NRC.
Our review of a number of these LERs indicates that loss of offsite power has occurred at your facility on April 6,1977 and September 12, 1978.
In order to complete our review of loss of offsite power events we require response to the enclosed request for information.
4 We request that you provide your response within 90 days of the receipt of this letter.
Sincerely, l4' %ddfu A. Schwencer, Chief Operating Reactors Branch !1 Division of Operating Reactors
Enclosure:
Request for Information cc: w/ encl osure 7
7 080 See next page t
t-46037o 7910:
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Mr. L. O. Mayer Northern States Power Company cc: Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.W.
Washington, D. C.
20036 Ms. Terry Hoffman Executive Director Minnesota Pollution Control Agency 1935 W. County Road B2 Roseville, Minnesota 55113 The Environmental Conservation Library Minneapolis Public Library 300 Nicollet Mall Minneapolis, Minnesota 55401 Mr. F. P. Tierney, Plant Manager Prairie Island Nuclear Generating Plant Northern States Power Company Route 2 Welch, Minnesota 55089 Joclyn F. Olson, Esquire Special Assistant Attorney General Minnesota Pollution Control Agency 1935 W. County Road B2 Roseville, Minnesota 55113 Robert L. Nybo, Jr., Chairman Minnesota-Wisconsin Boundary Area Commission 619 Second Street Hudson, Wisconsin 54016 Clarence D. Fierabend U. S. Nuclear Regulatory Commission P. 0. Box 374 Red Wing, Minnesota 55066 1217 081
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s ATTACHMENT A.
For losses of offsite power where less than all offsite power was lost:
1.
How many circuits 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 experier.ced 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.
S.
.~or 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 power 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 dec'y experienced just prior to or during the outage?
~
If so, please giva details, lowest frequency reached, decay rate, affects on equipment operation, etc.
6.
Date of Event.
C.
Were there any other loss of offsite power events other than we have listed?
If so, please give details of each event.
12!7 082
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