ML20040E423

Forwards LER 81-069/03L-0.Detailed Event Analysis Encl

ML20040E423
Person / Time
Site:	Oyster Creek
Issue date:	01/26/1982
From:	Carroll J GENERAL PUBLIC UTILITIES CORP.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20040E424	List: ML20040E423 ML20040E428
References
NUDOCS 8202040315
Download: ML20040E423 (2)

Text

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GPU Nuclear g g7 P.O. Box 388 Forked River, New Jersey 08731 609-693-6000 Writer's Direct Dial Number:

January 26, 1982 Mr. Ronald C. Haynes, Adnunstrator x j#

Region I United States Nuclear Regulatory Cmmission [,'sp /

03 631 Park Avenue as King of Prussia, Pennsylvania 19406 d '

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Dear Mr. Haynes:

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SUBJECT:

Oyster Creek Nuclear Generating Sta 'on M N Docket No. 50-219 g Licensee Event Report Reportable Occurrence No. 50-219/81-69/3L V' k This letter forwards three copies of a Licensee Event Report to report Reportable Occurrence No. 50-219/81-69/3L in cxxtpliance with paragraph 6.9.2.b.1 of the Technical Specifications.

Very truly yours, b/ ,&l, -

J. T. Carroll, Jr. /

[ActingDirectorOysterCreek JIC:dh /.

Enclosures cc: Director (40 copies)

Office of Inspection and Enforcemnt United States Nuclear Regulatory Cmmission Washington, D.C. 20555 Director (3)

Office of Management Information and Program Control United States Nuclear Regulatory Cmmission Washington, D. C. 20555 NRC Resident Inspector (1)

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

8202040315 920126 PDR ADOCK 05000219 S pop GPU Nuclear is a part of the General Public Utihties System gs 3

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0 OYSTER CREEK NUCLEAR GENERATING STATION Forked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/81-69/3L Report Date January 26, 1982 Ocairrence Date Deceber 30, 1981 Identification of Occurrence Core Spray high drywell pressure switches W-46A, W-46B and W-46D were found to trip at values greater than the Technical Specifications limit as given in Table 3.1.1, its D.2.

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

Conditions Prior to Occurrence The plant was shutdown with reactor coolant t mperature <212 F.

Description of Occurrence During surveillance testing, Core Spray high drywell pressure sensors W-46A, W-46B and W-46D tripped at values greater than the Technical Specifications limit of 2.0 psig. The testing yielded the following data:

Desired

_Swi',d1 As Found (psig) Setpoint (psig) As Left (psig)

W-46A 2.15 <2.0 1.96 W-46B 2.30 72.0 1.96 W-46C 1.92 72.0 1.92 W-46D 2.20 {2.0 1.93 Apparent Cause of Occurrence The cause of the occurrence was attributed to instrument repeatability. The switches were all last reset to trip at 2.0 psig. The latest results of ex-tensive testing and investigation into the manufacturer's data indicate that the total error which can be expected is as high as 4-4.5% of full range (.4 .45 psig). The setpoint changes in this case were'0.15 psig, 0.30 psig and 0.20 psig for switches W-46A, W-46B and W-46D respectively.

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Reportable Occurrence Page 2 Report No. 50-219/81-69/3L Analysis of Occurrence The Core Spray Syst s is made up of two independent loops, each of which will remove heat from the fuel assablies in the event of a loss of coolant accident (LOCA) . In order to initiate the Core Spray Systs, a signal frm any of the four high drywell pressure switches, or frm any of the four double-low water level switches nust be received.

In this case switches W-46A, W-46B and W-46D would have tripped within a fraction of a second delay upon increasing drywell pressure. The rmaining switch, W-46C, would have tripped within the Technical Specification limit of 2.0 psig and would have initiated the Core Spray Systs as required. Since the systm would have fulfilled its functional requirments as designed, the safet -

significance of the event'is muumized.

Corrective Action The switches were reset to trip within the Technical Specifications limit (note the "As Inft" values in the Description of Occurrence) . Based on an extensive Engineering study in conjunction with testing performed by an outside contractor, the "As Left" setpoint of these switches has subsequently been changed to reflect the inherent design error. The new setpoint of 1.85 psig is nore conservative, yet at the same time will not be too close to the normal operating range, in order to avoid an inadvertent initiation of the Core Spray Systs. Also, these switches will be replaced in a future refueling outage with an improved design.

Failure Data Manufacturer: ITT Barton Model: #288A Pressure Indicating Switch Range: 0-10 psig