05000219/LER-1982-006, Forwards LER 82-006/01T-0.Detailed Event Analysis Encl

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Forwards LER 82-006/01T-0.Detailed Event Analysis Encl
ML20041D791
Person / Time
Site: Oyster Creek
Issue date: 02/26/1982
From: Fiedler P
GENERAL PUBLIC UTILITIES CORP.
To: Haynes R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20041D794 List:
References
NUDOCS 8203090216
Download: ML20041D791 (4)
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LER-1982-006, Forwards LER 82-006/01T-0.Detailed Event Analysis Encl
Event date:
Report date:
2191982006R00 - NRC Website
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text

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h GPU Nuclear

- QQ g7 P.O. Box 388 Fcrked River, New Jersey 08731 609-693-6000 Writer's Direct Dial Number:

Mr. Ibnald C. Ilaynes, Adminstrator Region I c)

United States Nuclear Regulatory Camtission Q

631 Park Avenue King of Prussia, Pennsylvania 19406

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Dear Mr. Ilaynes:

93 MAR 0819W 4

SUBJECT: Oyster Creek Nuclear Generating Station sale s %

  • Docket No. 50-219 9

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Licensee Event Pcport Reportable Occurrence No. 50-219/82-06/lT 4

to This letter forwards three copies of a Licensee Event Peport to report Reportable Occurrence No. 50-219/82-06/lT in cxmpliance with paragraph 6.9.2.a. (2) and paragraph 6.9.2.b. (2) of the Technical Specifications.

With regard to the reporting requ.tr ments of the inoperability of IA83-A, as detailed in report, section 6.9.2.b specifies that the report is to be subnitted within 30 days. 'Ihe failure to subnit the required report in a timely fashion is attributed to not initiating a deviation report as required by our adni"istrative procedures.

Very truly yours, Peter B. Fiedler Vice President - Director Oyster Creek PBF:dh Enclosures cc: Director (40 copies)

Office of Inspection and Enforcanent United States Nuclear Regulatory Ca mission Washington, D.C.

20555 Director (3)

Office of Managanent Information and Program Control United States Nuclear Regulatory Camtission Washington, D. C. 20555 NBC Resident Inspector (1)

Oyster Creek Nuclear Generating Station Forked River, N. J.

8203090216 820226 PDR ADOCK 05000219 S

PDR t

GPU Nuclear is a part of the General Public Utihties System

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O OYSTER CREEK NUCLEAR GEFERATING STATICN Forked River, New Jersey 08731 Licensee Event Report Peportable Occurrence No. 50-210/82-06/1T Report Date February 26, 1982 Occurrence Date December 3, 1981 Identification of Occurrence While performing maintenance activities to repair a faulty electrmatic relief valve pressure switch, d.c. control power fuses 16F301A, 16F302A, 16F303A, and 16F304A were removed. This rendered Electromatic Relief Valve "A", and one trip systs in the Automatic Depressurization Systs (ADS) inoperable. Upon replace-ment of the relief valve pressure switch the fuses were replaced which returned Electrmatic Relief Valve A and the redundant ADS trip systs to operability.

This action was discovered on February 10, 1982, during the review of information concerning the pressure switch replacment.

IA83-A inoperability constitutes operation in a degraded node permitted by a limiting condition for operation per Technical Specification, section 3.4.B.1, reportable under section 6.9.2.b. (2).

Rendering the redundant ADS Trip Systm inoperable constitutes operation of a syst s when a parameter subject to a limiting condition is less conservative than the least conservative aspect of the limiting condition for operation establislxx1 in Technical Specification 3.1.A, table 3.1.1, its G, reportable under section 6.9.2.a. (2).

Conditions Prior to Occurrence Major Plant Parameters were as follows:

Power:

Reactor 1858 FMt Generator 650 FWe 15.3 x 10f gpn Flow:

Recirculation Feedwater 6.6 x 10 lbs/hr.

Description of Occurrence On Decmber 3,1981, the "A" Electrmatic Relief Valve (D4RV) lifted and inmediately rescated. The D4RV alarms cleared and a check of all the indica-tions indicated that the valve had rescated. As a precaution for the setpoint being too low, reactor pressure was decreased to 1010 psig to reduce the prob-ability of the D4RV "A" frm lifting again.

Reactor power was reduced to less j

than 1765 FMt and the isolation valves for both isolation condensers were surveilled to dcstonstrate their operability. The defecti"e pressure switch was replaced with a new switch, surveilled for the acceptabihty of setpoints and returned to service. Reactor pressure was then raised to 1020 psig.

F.

Ibportable Occurrence Page 2 Report Ib. 50-219/82-06/lTThe defective switch was sent to MICRO SWI'IGI for failure analysis on Decmber 18, 1981. During the investigations on this report it was discovered that prior to ccanencing the corrective maintenance, d.c. control power fuses 16F301A, 16F302A,16F303A and 16F304A were rcnoved. The effect of the rmoval of these fuses was the inoperability of EMEW "A",

the loss of the pressure relief function associated with pressure switch IA83-A, and the defeating of one of the redundant ADS trip systms.

Apparent Cause of Occurrence

'Ihe failed pressure switch, IA83-A, (Barksdale bbdel No. B2S-H12SS) has two microswitches (MICPO SWI'IGI Model No. BZ-R178) inside it. The MICRO SWI'IGI report indicated that there was a material build-up on the normally closed side of the high pressure switch moving contact. This could have resulted in the nonentary bridging of the normally closed contacts and actuation of Electramtic Relief Valve A.

The high resistance path for the current across these contacts could have prevented the pick-up of the IA83-A control relay on an intermittent basis.

The narrow air gap of this type of switch, an AC designed switch handling a load of 125 VDC in the range of 0.150 to 0.180 amps, makes the switch sensitive to very muumal material transfer conditions.

The cause of the ADS Trip System inoperability was due to rcnoval of the d.c.

control fuses without realizing its conscquences on the ADS control logic.

Analysis of Occurrence The function of EMIN's is to provide a rapid depressurization of the reactor pressure vessel during a small pipe break, satisfying the ADS logic or procedure rcquircments, and to autmatically relieve a vessel overpressure condition.

In igs " auto" node for overpressure protection, IA83-A high swftch trips at 1059 1g psig to open DilW "A" and the low switch opens at 100915 Psig to close the valve.

Rcnoval of the d.c. control power fuses resulted in the inoperability of "A" IMN and the loss of one trip systm of the ADS. The redundant trip syst m was still operable. Had a cc.1dition been present which rcquired the operation of the ADS, the redundant systcm would have actuated the four rmaining valves to depressurize the reactor.

Corrective Action

As an innediate action, reactor power was reduced to less than 1765 MWt, reactor pressure was reduced to 1010 psig and the isolation condenser valves were dcnonstrated to be operable. The pressure sensor IA83-A was replaced with a new 125 VDC rated switch bbdel No. B2S-M12SS.

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hrtableOccurrence Page 3 Report tb. 50-219/82-06/lTOn the basis of the Microswitch report, B, C, D, and E EMlW pressure sensors (ledel'No. B2S-Ill2SS) were replaced with 125 VDC rated (Model No. B2S-+112SS) switches. Transient suppression devices (metal oxide varistors) were installed in parallel with all the U4ru solenoids and all of the control relay coils in the IMW control circuit.

Additionally, this Reportable Occurreroe will be incorporated in the required reading program for Shift Operations Supervision and Instrument Depart:nent personnel to avoid future occurrences with this circuit and to stress the importance of subnitting Deviation Reports at the time a failure or discrepancy is recognized. The subject fuses in the circuit for A and B FM W's which defeat the redundancy of the ADS will be physically labeled with a caution on rmoval consequences due to its uniqueness.

Failure Data Manufacturer: Barksdale Model No:

B2S-Ill2SS

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