ML20038C716

RO 50-219/81-64/01P:on 811203,containment Spray High Drywell Pressure Switches IP-154A,IP-15B,IP-15C & IP-15D Tripped at Value Greater than Tech Specs.Caused by Instrument Repeatability.Switches Reset

ML20038C716
Person / Time
Site:	Oyster Creek
Issue date:	12/09/1981
From:	Carroll J JERSEY CENTRAL POWER & LIGHT CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
RO-50-219-81-64, NUDOCS 8112140069
Download: ML20038C716 (3)

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IESIGNATED ORIGItrAI, l CCellfied By bo _

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'IO: Ronald Haynes Directorate of Regulatory Operations

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q 4V FROM: Jersey Central Power & Light Cmmny b 'Q Oyster Creek Nuclear Generating Stati g g Docket; No. 50-219 Forked River, New Jersey 08731 SUM ECT: Reportable Occurrence Report No. 50-219/81-64/0lP The following is a preliminary report being subnitted in cairpliance with the Technical Specifications, paragraph 6.9.2.A.5.

Preliminary Approval:

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/T.T. Carroll,Jr. /

/ Acting Director Oyste2jf eek

Director (2)

Office of Management Information and Program Control U.S. Nuclear Regulatory Cami.ssion washington, D. C. 20555 f

NBC Resident Inspector (1)

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

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OYSTER CREEK NUCIEAR GliNERATING STATION Forked River, New Jersey 08731 Licensee Event Report-Reportable Occurrence Nc. 50-219/81-64/0lP Report Date Del 4,1981 1 Occurrence Date Deconber 3, 1981

) Identification of Occurrence The Contaiment Spray high drywell pressure switches IP-15A, IP-15B, IP-15C, and i IP-15D tripped at a value greater than the limit given in the Technical Specifica-tions Table 3.1.1 itan E.1.

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

Conditions Prior to Occurrence l The plant was operating at steady state power.

F l Major Plant Parameters Power: Reactor 1859 FWt

• Generator 650 fee Flow: Recirculation 15.4 x 10 gpn Feedwater 6.94 x 10 lb/hr Description of Occurrence On Thursday, Decancer 3, at 4:00 P.M., while performing the " Containment Spray Systan Autanatic Actuation Test", the IP-15A, IP-15B, IP-15C and IP-15D trip 4

points were found to exceal the Technical Specification limits. Gurveillance f testing yielded the following data:

1 Desired Switch Setpoint (psig) As Found (psig) A_s Left (psig)

IP-15A <2 2.1 1.95 IP-15B 72 2.02 1.99 IP-15C 72 2.03 2.00 IP-15D [2 2.03 1.94

Reportable Occurrence Page 2 Report No. 50-219/81-64/OlP Apparent Cause of Occurrence The cause of the occurrence was attributed to instrment repeat ability. 'Ihe switches were last reset to trip between 1.90 and 2.0 psig, so the maxinun change could be .20 psig (2.1 - 1.9) . This is within the design range of instrument repeatability.

Analysis of Occurrence The Containment Spray Systs is made up of two independent cooling loops, each of which is capable of rer:oving heat frm the primary containment in the event of a loss of coolant accident. In order to initiate the Containment Spray Systs, a cmbination of a high drywell pressure signal plus a reactor low-low water level signal nust be received.

Although the high drywell pressure switche.s would have tripped at a slightly higher pressure than the desired setpoint, their actuation would have only been delayed a fraction of a second (approximately 0.1 second frm the start of the design basis loss of coolant accident) . However, the reactor low-low water level setpoint is'not reached until almost 4 seconds frcm the start of the design basis loss of coolant accident. Due to this fact, the Malay in actuation of the pressure switches would not have affected the initiation of the Containment Spray Systcm, and, therefore, the safety significance of the occurrence is considered muumal.

Corrective Action The switches were all reset to trip within the required limit (note,91e "As Inft" values in the Description of Occurrence) . It has been recatmended that these type of snap-action switches be replaced with an improved nodel.

Failure Data Manufacturer: I'IT Barton bbdel: 228A Indicating Pressure Switch Range: 0-10 psig

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