ML20027C955

LER 82-049/03L-0:on 820920 & 22,Channels 2 & 3 on Containment post-accident Radiation Monitor Re 4597BA Were Reading High.Caused by Problem in Microprocessor Software. New Set of Software Installed & Faulty Actuator Replaced

ML20027C955
Person / Time
Site:	Davis Besse
Issue date:	10/19/1982
From:	Eldred D TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20027C953	List: ML20027C952 ML20027C955
References
LER-82-049-03L, LER-82-49-3L, NUDOCS 8210280078
Download: ML20027C955 (2)

Text

NRC FOZM 366 U. S. NUCLEAR REGULATtRY COMMISSION (7 77) , ,

LICENSEE EVENT REPORT CONTROL BLOCK: l 1

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(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) y d lOlHl Dl Bl S l 1 l@l 0 l 0 l- l 0 l 0 l 0 l 0 l 0 l- l0 l 025 l@l 26 4lLICENSE ll 1l 1l 1l@l57 CAT TYPE JO l

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@l019121018 69 EVENT DATE l2 l@l 74 75 llREPORT 0l ll DATE 918l 2l@ 80 7 8 61 DOCKET NUMBER LVENT DESCRIPTION AND PROBABLE CONSEQUENCES Oto o 2 l (NP-33-82-58) At 2030 hours0.0235 days <br />0.564 hours <br />0.00336 weeks <br />7.72415e-4 months <br /> on 9/20/82 and again at 0150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> on 9/22/82, the Controll

o i3; l Room operator noticed that Channels 2 and 3 on RE 4597BA (Containment Post Accident l It was discovered that the readings would go iol45 l Radiation Monitor) were reading high. l l O l s i j from high to normal to zero intermittently. On both occurrences, the monitor was l l 0 l6 l l declared inoperable, and the unit entered the action statement (a) of Technical Speci g ,

There was no danger to the health and safety of the public or l l0 l7l 1 fication 3.3.3.6.

l0j8l l station personnel. The redundant system (RE 4597AA) was operable. l 80 7 8 9 C DE CODE S 8C OE COMPONENT CODE SUBCOD'E SU E Q l Bl B l@ W@ W@ l 1l Nl Sl Tl Rl Ul@ lX l@ y @ 13 18 19 20 7 8 9 10 11 12 SEQUENTIAL OCCURRENCE REPORT REVISION EVENT YEAR REPORT NO. CODE TYPE N O.

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_ l21 8l22 2l 23 24 26 27 78 N 30 31 32 TAK N A ON oN PL NT M HOURS 22 S8 i FoR 8. SL PPLI MANUF CTURER l0 l0 l0 lp l [_Yj@ lN lg [N _jg l K l 0 l 2 l 0 lg lAlgl34Z 33 lg l35Z l g l36Zl@ 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 11 l o l l Af ter the second occurrence, it was discovered that the micro-processor sof tware was j i i lthe problem. A new set of software was programmed by Kaman Sciences Corporation i g,,2, land installed. During checkout of the new software, a faulty flow control valve l l 1 l a l l actuator was discovered. A new actuator was installed, calibrated and tested. l i , lST 5032.01 was run, and the monitor was declared operable at 1555 hours0.018 days <br />0.432 hours <br />0.00257 weeks <br />5.916775e-4 months <br /> on 9/29/82. l 80 7 8 9 ST S  % POWER oTHER STATUS oIS O Y DISwOVERY DESCRIPTION 1 s (_E,J@ l0 l 8 l 8 l@l NA l l A [gl Operator discovery l

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Pu8tisTY B210280078 821019 NRC USE ONLY 05000346 ,

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TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE S_UPPLEMENTAL INFORMATION FOR LER NP-33-82-58 DATE OF EVENT: September 20 and 22, 1982

_ FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Containment Post Accident Radiation Monitor, RE 4597BA, Channels 2 (Particulate) and 3 (Iodine) failed to respond correctly Conditions Prior to Occurrence: The unit was in Mode 1 with Power (MWT) = 2437 and Load (Gross MWE) = 800.

Description of Occurrence: At 2030 hours0.0235 days <br />0.564 hours <br />0.00336 weeks <br />7.72415e-4 months <br /> on September 20, 1982, the Control Room operator noticed that Channels 2 and 3 on RE 4597BA (Containment Post Accident Radiation Monitor) were reading much higher than the redundant monitors channels on RE 4597AA. Upon closer investigation, it was discovered that the readings would go from high to normal to zero intermittently. The monitor was declared inoperable, and the station entered Technical Specification 3.3.3.6, Action (a).

No reduction of power was required. I6C personnel reset and reprogrammed the micro-processor and checked the operation. Everything responded correctly. Operations personnel ran Surveillance Test ST 5032.01 and declared the unit. operational at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> on September 21, 1982. At 0150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> on September 22, 1982, the unit

• again failed to respond correctly (identical problem), and it was again declared inoperable. The station again entered Technical Specification 3.3.3.6, Action (a).

Designation of Apparent Cause of Occurrence: Upon investigation by I&C personnel, it was discovered that the micro-processor software was the problem. On the first occurrence, the reprogramming was successful. On the second occurrence, a new set of software was programmed by Kaman Sciences Corporation and installed. A factory l

representative was also sent to site. During checkout of the new software, a i faulty flow control valve actuator was also discovered. A new actuator was in-l stalled, calibrated, and tested. The new software was tested, and the monitor was released to Operations by the I&C personnel.

Analysis of Occurrence: There was no danger to the health and safety of the public or station personnel. The redundant system (RE 4597AA) was operable as were all six containment area radiation detectors.

Corrective Action: On the first occurrence, the reprogramming of the micro-processor was successful. On the second occurrence, the replacement of the soft-ware and the new flow control valve actuator corrected the problems with the operation of the monitor. Operations ran Surveillance Test ST 5032.01 at 1555 hours0.018 days <br />0.432 hours <br />0.00257 weeks <br />5.916775e-4 months <br /> on September 29, 1982 and declared the monitor operational. This removed the station from Action (a) of Technical Specification 3.3.3.6.

Failure Data: There have been no previous similar occurrences.

LER #82-049