ML19256C970
| ML19256C970 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 06/20/1979 |
| From: | Klingler G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-79-173, NUDOCS 7910150800 | |
| Download: ML19256C970 (1) | |
Text
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PRELIMINARY NOTIFICATION June 20, 1979 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PN0-79-173 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance.
The information p, resented is as initially received without verification or evaluation and 1s basically all that is known by IE staff on this date, racility:
Dairyland Power Cooperative La Crosse Boiling Water Reactor (DN 50-40E) Genoa, Wisconsin
Subject:
INSTRUMENT DOWER SUPPLY DISRUPTION - REACTOR SCRAM At 11:10 a.m., on June 18, 1979, while operating at 91% power, an instrument technician inadvertently caused a pertubation in the instrument power supply which resulted in a reactor scram.
The instrument technician was working on a primary system conduc-tivity meter and thought he had isolated the power supply.
- However, while working on the meter, he shorted out the power supoly.
The resultant spikes in the circuit blew the fuses to power supplies for the reactor pressure transmitters.
This in turn resulted in a nain steam isolation valve closure and a reactor trip.
All systems functioned as designed during this event, tne shut-down condenser was automatically actuated, and the reactor vessei level and pressure remained within normal bounds.
The blown fuses were
, replaced, and the unit was returned to operation.
The plant is currently (9:00 a.m. on June 19,1979) at 35% power and expects to be at full power by the end of the week.
Neither the licensee nor Region III plans to issue a pressure release.
Tne State of Wisconsin will be notified.
The Region III Duty Officer was notified of this occurrence by tele-phone from the licensee at 8:17 p.m. on June 18, 1979.
Contact:
G. Klingler, IE x28019; F. Nolan, IE x28019; S. Bryan, IE x28019 Distribution:
Transmitteo H St /4lfd Cnairman Hendrie Commissioner Bradford S. J. Chilk, SECY Comnissioner Kennedy Commissierer Ahearne C. C. Kammerer, CA Commissioner Gilinsky ACRS (For Distribution)
//.*66,~
Transmitted:
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L. V. Gossick, ED0 H. R. Denton, NRR Region
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R. G. Ryan, OSP SSBldgf' J. Cummings, 01A H. K. Shapar, ELD W. J. Dirc s, NMSS R. Minogue, SD S. Levine, RES 1450 168 PRELIMINARY NOTIFICATION 7910150(70 6