05000219/LER-1982-056, Forwards LER 82-056/01T-0.Detailed Event Analysis Encl

Forwards LER 82-056/01T-0.Detailed Event Analysis Encl

ML20067D856
Person / Time
Site:	Oyster Creek
Issue date:	12/08/1982
From:	Fiedler P GENERAL PUBLIC UTILITIES CORP.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20067D857	List: 05000219/LER-1982-056, Forwards LER 82-056/01T-0.Detailed Event Analysis Encl
References
NUDOCS 8212210372
Download: ML20067D856 (4)

LER-2082-056, Forwards LER 82-056/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
2192082056R00 - NRC Website

text

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GPU Nuclear NMCIMF P.O. Box 388 Forked River, New Jersey 08731 609-693-6000 Writer's Direct Dial Number:

December 8, 1982 Mr. Ronald C. Haynes, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

Dear Mr. Haynes:

Subj ect: Oyster Creek Nuclear Generating Station Doeket No. 50-219 Licensee Event Report Reportable Occurrence No. 50-219/82-56/0lT This letter forwards three copies of a Licensee Event Report to report Reportable Occurrence No. 50-219/82-56/0lT in compliance with paragraph 6.9.2.a.2 of the Technical Specifications.

Very truly yours, e'A Peter'B. Fiedler 0

Vice President and Director Oyster Creek PBF:lse Enclosure s cc: Director (40 copies)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission I 1

Washington, D.C. 20555 Director (3)

Of fice of Management Information and Program Control U.S. Nuclear Regulatory Commission Washington, D.C. 20555 l

! NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, NJ 08731 l 8212210372 821208 r PDR ADOCK 05000219 S PDR l

GPU Nuclear is a part of the General Pubhc Utilities System gf,1,b ;

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. . . o OYSTER CREEK NUCLEAR GENERATING STATION Forked River, New-Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/82-56/OlT Report Date December 8,1982 Preliminary Report Date November 23, 1982 Occurrence Date November 20, 1982 Identification of Occurrence The stack gas was not continuously monitored as required by Technical Specification 3.6.A.3.

This event is considered to be a reportable occurrence as defined in the Technical Specifications, paragraph 6.9.2.a.2.

In addition, the operability requirement specified in Technical Specification 3.7.A.1.f was not met when 24V DC power panel A was in a degraded voltage condition for approximately thirty minutes. This related event is considered to be a reportable occurrence as defined in the Technical Specifications, paragraph 6.9.2.b.2.

Conditions Prior to Occurrence The major plant parameters at the time of the occurrence were:

Reactor critical in run mode Reactor Power: 996.9 MWt Generator Output: 312 MWe Description of Occurrence On Friday, November 19, 1982 between 1000 and 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br />, the A2 -24V DC battery was placed in the equalize charge mode. At approximately 1110 hours0.0128 days <br />0.308 hours <br />0.00184 weeks <br />4.22355e-4 months <br />, a

! "24V system of f normal" alarm was received in the control room. Since the control room operators had been informed to expect an alarm when the A2 battery was.placed on equalize charge and since the voltage and operation of the nuclear instrumentation being fed from the 24V DC system were normal, no additional operator action was taken.

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Licensee Event Report Page 2 Reportable Occurrence No. 50-219/82-56/OlT On Saturday, November 20, 1982 at approximately 1509 hours0.0175 days <br />0.419 hours <br />0.0025 weeks <br />5.741745e-4 months <br />, control room operators noticed certain Source Range Monitor (SRM) and Intermediate Range Monitor (IRM) indications beginning to fluctuate. A short time later, both stack gas monitor indications were observed failing downscale. , Instrument and Electrical Department personnel were notified to investigate the problem. At approximately 1525 hours0.0177 days <br />0.424 hours <br />0.00252 weeks <br />5.802625e-4 months <br />, an electrician found the output breaker _ of the A2 battery chargar in the tripped position. This condition had caused nuclear instrumentation, and process radiation monitors for the stack gas and service water systems, on instrument panels 1R and 3R, *o operate on battery power only. Since the' annunciator was already in an alarm mode and since there is only a common annunciator for the 24V DC system, the subsequent DC low voltage condition would not cause another alarm in the control room. This prevented the control room operators from recognizing the condition immediately upon occur re nce. The electrician checked, reset and closed the breaker. Within a few minutes, the condition indication and alarn for the system returned to normal.

A reactor shutdown was initiated at approximately 1510 hours0.0175 days <br />0.419 hours <br />0.0025 weeks <br />5.74555e-4 months <br /> in compliance with Technical Specifications 3.6.A.3 and 3.7.B, af ter Operations personnel noticed the stack gas indication for A and B monitors failing downscale. The shutdown procedure was then terminated at approximately 1535 hours0.0178 days <br />0.426 hours <br />0.00254 weeks <br />5.840675e-4 months <br /> af ter the af fected systems were returned to normal with the reset of the A2 battery charger b reaker.

Apparent Cause of Occurrence The apparent cause of occurrence was due to drif t of the setpoint for the overvoltage alarm relay. In addition, personnel error involving miscommunication and interpretation of the alarm was contributory. When the equalizing charge was initially placed on the A2 battery, the equalizing voltage apparently increased past the overvoltage setpoint which caused the output breaker of the A2 battery charger to trip and an alarm to annunciate'in the control room. The alarm was interpreted by the operators to be caused by the placement of the battery on equalize charge. Therefore, no additional action was taken at that time.

Analysis of Occurrene The "A" 24V DC system provides power to liquid and gaseous process radiation monitors on instrument panel 1R, area radiation monitors on panel 2R and neutron (SRM and IRM) monitoring on panel 3R. Loss of the -24V DC power supply prevented continuous nonitoring of the stack gas system. How2Ver, since the stack gas monitoring system was inoperable for approximately thirty (30) minutes, during which time the off gas and reactor building ventilation monitoring systems remained in service and showed normal indications, the safety significance of this occurrence is considered minimal. The rod block \

trip function associated with SRM and IRM neutron monitoring is not requirej when in the RUN mode.

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F 0 Licensee Event Report Page 3 Reportable Occurrence No. 50-219/82-56/0lT Corrective Action Immediato corrective action was to check, reset and close the output breaker of A2 battery charger to establish the required 24V DC system voltage. Affected I

nuclear instrumentation and process radiation monitoring was returned to n ormal . The overvoltage relay trip setpoint was checked and rese* to the proper value.

An evaluation will be initiated to investigate and determine any corrective actions necessary to improve the system.

ce controls will be enhanced to require checking of alarm conditions

. aver an equalizing charge is initiated / completed.

A copy of this Licensee Event Report will be sent to the Operating Experience Assessment and Implementation Committee (0.E.A.I.C.) for proper distribution to all operations and instrument / electrical maintenance personnel for required reading . It also will be routed to the Training Department for " Lessons Learned" in the training program.

Failure Data General Electric Model No. CRW984BN25WG2356 24V DC Battery Charger c

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