05000318/LER-1980-005-03, /03L-0:on 800122,five Channel B Trip Units Were Bypassed Due to Spurious High Power Levels.Caused by Noise from Excore Nuclear Instrument Upper Subchannel Detector. Troubleshooting Planned for Next Cold Shutdown

/03L-0:on 800122,five Channel B Trip Units Were Bypassed Due to Spurious High Power Levels.Caused by Noise from Excore Nuclear Instrument Upper Subchannel Detector. Troubleshooting Planned for Next Cold Shutdown

ML19296D129
Person / Time
Site:	Calvert Cliffs
Issue date:	02/22/1980
From:	Heibel R, Rizzo P BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19296D124	List: 05000318/LER-1980-005, Forwards LER 80-005/03L-0 05000318/LER-1980-005-03, /03L-0:on 800122,five Channel B Trip Units Were Bypassed Due to Spurious High Power Levels.Caused by Noise from Excore Nuclear Instrument Upper Subchannel Detector. Troubleshooting Planned for Next Cold Shutdown
References
LER-80-005-03L, LER-80-5-3L, NUDOCS 8002290374
Download: ML19296D129 (2)

LER-1980-005, /03L-0:on 800122,five Channel B Trip Units Were Bypassed Due to Spurious High Power Levels.Caused by Noise from Excore Nuclear Instrument Upper Subchannel Detector. Troubleshooting Planned for Next Cold Shutdown

Event date:
Report date:
3181980005R03 - NRC Website

text

LICENSEE EVENT REPORT CONTROL BLOCK: l l

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8 60 61 DOCKET NUM8ER 68 69 EVENT DATE 74 75 REPORT C ATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l At 0445 on January 22, 1980, the followino Channel B trips units were o

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a i bypassed:

power level hich. reactor coolant inw finw +homal ra rnin /

I I low pressure, loss of turbine, and axial flux offset. The trio uni n i

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I were bypassed because spurious high power levels were beino experienced.

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s All Channel B trip units were returned to their nomal positions at 1720 O

e OI7 [on January 23, 1980.

The remaining three reactor protection channels remained I

ola operable throughout this event as recuired by T. S. 3.3.1.1.

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l Wl lj2l0lg 33 34 35 36 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i

o l This is a recurrence of a problem reported as LER 79-50 for (U-2/ Docket No.

I ii ii i I 05000318).

Intemittent noise from Excore Nuclear Instrument 2-NE-006 rp q l upper subchannel detector is the apparent cause of the spurious trips.

i l Further troubleshooting is planned during the next unit cold shutdown.

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% POWER OTHER STATUS Of RY OtSCOVERY DESCRIPTION

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lllll1llllll l ITTOl I Nf@ DESCRIPTION ISSUE 68 69 80 ;

7 8 9 10 R. P. Heibel/P. G. Rizzo pgang;(301)269-4749/4786 2

NAME OF PREPARER

LER NO.

80-05/3L DOCKET !!0. 50-318 EVENT DATE 01/22/30 REPORT DATE 02/22/d0 ATTACHMENT EVENT DESCRIPTION /HD PROBABLE CONSE0VENCES:

(CONTIliUED)

LER 79-50 (U-2) is a similar event.

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