ML19261B332

LER 79-010/03L-0:on 790112,Sys 7 Data Logger Experienced Core Dump,Voiding Computer Memory Bank Which Rendered Remote Monitoring of Fire Detection Sys Inoperable & Placed Unit in Action Statement of Tech Spec 3.3.3.8.Cause Unknown

ML19261B332
Person / Time
Site:	Davis Besse
Issue date:	02/09/1979
From:	Kocis R, Kovach S TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19261B329	List: ML19261B327 ML19261B332
References
LER-79-010-03L, LER-79-10-3L, NP-33-79-11, NUDOCS 7902150336
Download: ML19261B332 (2)

Text

U.S. NUCLEAR REGULATORY COMMISSION NRC FORM 366 (7 77)

LICENSEE EVENT REPORT

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(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) l0 l1l l 0l Hl Dl Bl Sl 1l@l 0 l 0l -l 0LICENSE l 0l NUMBER Nl P l F l -l 0]253 l@l 2ti 4LICENSE l ll 11 TYPEIlJO1 @l l

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EVENT DATE 74 75 REPORT DATE 80 7 8 60 61 DOCKET NUMBER EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h 10121 l Short1v af ter 0121 hours0.0014 days <br />0.0336 hours <br />2.000661e-4 weeks <br />4.60405e-5 months <br /> on 1/12/79, and at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> on 1/25/79 the System 7 Data l o 3 LogFpr experienced a " core dump" which voided the memory bank of the computer. Withot4t 5

j o 4 l its program in memory, the computer and its typewriters ceased functioning. These gol3l events rendered the remote monitoring of the Fire Detection System inoperable and ]

lplaced the unit in the Action Statement of Technical Specification 3.3.3.8. There was!

o s In each case, a l o 7 l no danger to the health and safety of the public or unit personnel.

o a I fire watch was established and the local fire alarm panels were monitored. I CAUSE COMP. VALVE SYSTEM CAUSE SUBCODE CODE CODE SUSCODE COMPONENT CODE SUBCODE 7

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_ 21 22 COMPONENT ATTACHMENT NPRO-4 PRIME COMP.

ACTION FUTURE EFFECT SHUTDOWN SUBMITTED FORMbuB. SUPPLIER MANUFACTURER TAKEN ACTION ON PLANT F.tE TH OD HOURS l33B [glJ4Z lg l33Zlg g@ l0l0l0l ]Q 41 42 N]g l43A l@ 44 I

Ol1l0l@ 47 J6 3/ 40 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i o ] The specific cause of each " core dump" is present1v unknown. No evidence of circuitrvi

i ;i j l failure or power loss to the cabinct has been discovered. The program was reloaded atl

, , , , y l approximately 0720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> on 1/12 and at 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> on 1/25. This returned the system I g,;3g to normal operation and removed the unit from the Action Statement of Technical Speci-l l

g,,4glfication 3.3.3.8. so 7 8 9

• OTHER STATUS DISCOV RY DISCOVERY DESCRIPTION ST S . POWER l

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W l 80101 7 9 Ol@l NA 11 12 80 LOSS OF 08 DAUAGE TO FACILIT Y TYPE DE SC HIP TION I 9 N.\ b0 7 8 9 10

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. TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-79-ll D TE OF EVENT: January 12, 1979 and January 25, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Fire Detection System became inoperable when remote indication on data logger typewriters was lost Conditions Prior to Occurrence: On January 12, the unit was in Mode 1, with Power (MWT) = 1800, and Load (Gross MWE) = 600. On January 25, the unit was in Mode 5, with Power (MWT) = 0, and Load (Gross MWE) = 0.

Description of Occurrence: Shortly after 0121 hours0.0014 days <br />0.0336 hours <br />2.000661e-4 weeks <br />4.60405e-5 months <br /> on January 12, 1979, and at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> on January 25, 1979, the System 7 Data Logger experienced a " core dump" which voided the memory bank of the computer. Without its program in memory, the computer and its typewriters ceased to function.

At each of these times, the Fire Detection Remote Monitoring System was inoperable, and the unit was placed in the Action Statement of Technical Specification 3.3.3.8.

In each case, a fire watch was established within the honr specified by the Action Statement, and maintained until the System 7 computer was returned to operability.

Designation of Apparent Cause of Occurrence: The specific cause of the " core dump" is presently unknown. An investigation subsequent to the events gave no evidence of circuitry f ailure or power loss to the cabinet.

Analyais of Occurrence: There was no danger to the health and safety of the public or to unit personnel. Although the events removed remote monitoring of the Fire Detection System, the fire watch in ef fect returned the fire protection by cubsti-tuting manual observation for the System 7 and typewriters, and by monitoring the local fire alarm panels which were not affected by the loss of the System 7 computer.

Corrective Action: The System 7 program was reloaded at approximately 0720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> on January 12, 1979 and at 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> on January 25, 1979. This placed the system back in normal operation and removed the unit f rom the Action Statement of Technical Specification 3.3.3.8.

Failure Data: There have been no previously reported similar occurrences.

LER #79-010 f