ML20009A664

Forwards LER 81-023/03L-0.Detailed Event Analysis Encl

ML20009A664
Person / Time
Site:	Oyster Creek
Issue date:	07/06/1981
From:	Finfrock I JERSEY CENTRAL POWER & LIGHT CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20009A665	List: ML20009A664 ML20009A668
References
NUDOCS 8107130453
Download: ML20009A664 (3)

Text

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P O OYSTER CREEK NUCLEAR GENERATING STATION EH N1 Elf Ir L)j Cd,57"f0?OEO w w c - s.sv-(609)693-6000 P.O. BOX 388

• FORKED RIVER

• NEW JERSEY

• 08731 July 6, 1981 Mr. Boyce H. Grier, Director Office of Inspection and Enforcanent Region I United States Nuclear Regulatory Camission 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Mr. Grier:

SURTECT: Oyster Creek Nuclear Generating Station Docket No. 50-219 Licensee Event Report Reportable Occurrence No. 50-219/81-23/3L This letter forwards three copies of a Licensee Event Report to report Reportable Occurrence No. 50-219/81-23/3L in orpliance with paragraph 6.9.2.b.2--of,the '"echnical Specifications.

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,%s very truly yours, fj/m/RE0![DQff g, i

d Mu.L1t 0 l93l

• ran R. Finf r.

%2; mgguro: v/ ice President - JCP&L

\ 'fL C' irector - Oyster Creek IFF:dh \ P- <@/

l Enclosures / \/

cc: Director (40 copies) i Office of Inspection and Enforce ent United States Nuclear Recrilatory Ccmrissicn i Washington, D.C. 20555 Director (3)

Office of Managenent Infonration and Program Control l

United States Nuclear Regulatory Ca mission Washingtcn, D. C. 20555 NRC Pesident Inspector (1) h I

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

8107130453 810706 PDR ADOCK 05000219 S PDR

OYSTER CREEK WUCLEAR GENERATING STATION Ebrked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/81-23/3L Report Date July 6, 1981 Occurrence Date June 3, 1981 Identification of Occurrence A limiting condition for operation was exceeded when the differential pressure between the drywell and suppression chamber was not maintained within the ac ptable operating range given in Figure 3.5-1 of the Technical Specifications.

This is a violation of Technical Specification paragraph 3.5.A.9a.

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

Conditions Prior to Occurrence

'Ihe plant was at steady state power.

Major Plant Parameters:

Power: Reactor 1563 Mht Generator 470 MWe Flow: Recircalation 13.0 x 104 y i Feedwater 5.13 x 106 lb/hr Description of Occurrence l

On Wednesday, June 3, 1981, at approximately 2230, dryw l1 to torus differential i pressure was below the acceptable value as defined by figure 3.5-1 in the Technical Specifications. The incident occurred when the drywell was vented to zero PSIG in order to initiate a nitrogen high flow purge to reduce oxygen concentration.

Previously the oxygen content in the drywell was increasing towards the 5 percent

! limit. The Nitrogen Makeup System was utilized in an effort to reduce the amount of oxygen, however, the oxygen percentage continued to rise frca 4.0% to 4.75% in approximately fourteen hours. W e instrumentation to measure drywell was checked by the Instrument Department and determined to be accurate.

AgterconsultationwiththeGroupShiftSupervisor,basedonthediscussionin the Analysis of Occurrence Section of this report, a managenent decision was l made to vent the drywell below the specified operating range. At the time of j the incident, the torus level was indicatal at 4.5 inches which corresponds to 3.5 feet downcmer subnergence. 'Ihe mimmum acceptable drywell to torus differ-ential pressure for this submrgence is 1.0 PSID.

l 1

Peportable Occurrence Page 2 Report No. 50-219/81-23/3L Apparent Cause of Occurrence The cause of the incident was the increasing oxygen concentration in the drywell.

Subsequent to the inerting of the drywell, a mnsiderable amount of noisture was found in the instrunent lines of the oxygen analyzer. It is suspected that a mositure bui1% caused an erroneous operation of the analyzer, indicating high oxygen concentrations. This was substantiated by no further increase in cxygen concentration once the noisture was retoved.

The maximum drywell oxygen mndmt is 5 percent according to Technical Specifica-tion 3.5.A.6. After unsuccessful atteupts at nitrogen makeup and discovering the source of the leak, the drywell was vented and differenhal pressure re-established.

Analysis of Occurrence Maintaining drywell to torus differential pressure within the range specified on figure 3.5-1 of the Technical Specifications assures the integrity of the torus when subjected to post ILCA torus hydrodynamic forces. The Technical Specifica-tions state in section 3.5.A.9, however, that the differential pressure may be reduced to less than the range specified on figure 3.5-1 for a maxinum of four hours during required operability testing of the drywell torus vacuum breakers.

In addition, specification 3.5.A.9.b states that "if the differential pressure of specification 3.5.A.9.a cannot be maintained, and the differential prescure cannot be restored within the subsequent 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> period, an orderly shutdcun shall be initiated". Since the differential pressure was reestablished within two hours, a plant shutdown was not initiated. Based on the above, the safety significance is considered to be min mal.

Corrective Action

'Ihe drywell was reinerted and differential pressure was increased to the normal operating range. Procedures will be reviewed to assure that operators and instrument technicians will be guided to specifically nMress the noisture problen. Additionally, an Engineering Pequest has been subnitted to evaluate or upgrade the oxygen analyzer instrumentation as a result of past experiences of false oxygen concentration indications.

Failure Data Not applicable.

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