ML19305D343

LER 80-009/03L-0:on 800310,during Normal Operation,Nuclear Power Range Channel 1N44 Was Inoperable for Several Minutes. Caused by latch-up of High Voltage Power Supply Due to Spike on Yellow Instrument Bus.Fuses Were Removed & Reset

ML19305D343
Person / Time
Site:	Prairie Island
Issue date:	04/09/1980
From:	Hunstad A NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19305D341	List: ML19305D340 ML19305D343
References
LER-80-009-03L, LER-80-9-3L, NUDOCS 8004140440
Download: ML19305D343 (1)

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7 8 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h ITlTI l During normal operation. Nuclear Power Range Channel 1N44 was inoperable for a few l l0l3l l minutes. Immediately after loss of the channel, its bistables were put in trip. No l O 4 l effect on public health and safety. Redundant channels were operable. Tech Spec l O s l3.5 applies. l 0 6 l l 10171 l l .

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33 3S 36 37 40 el 42_ 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h W l The high voltage power supply for the detector " latched up" due to a spike on the l i i l Yellow Instrument Bus. This is characteristic of these power supplies. Removal and I

, 2 l reinsertion of the power supply fuses allowed the circuitry to reset. I i 3 l l mI 8 9 7 80 l ,

ST S  % POWER OTHER STATUS DfS O RY DISCOVERY DESCR!PTION Ii 15 I (_E_j@ l1 l 0 l 0 l@l N/A l (_A_j@l Control Room Annunciator l A TIVITY CO TENT RELE ASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE i 6 @ [Z_j@l NA l l NA l 7 8 9 10 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION 1 7 l0 l 0 l 0 l@l Z l@l NA l

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NAME OF PREPARER

. . nstad PHONE:

612-388-4767 2 8004140 %