05000269/LER-1983-003, Forwards LER 83-003/03L-0.Detailed Event Analysis Encl

Forwards LER 83-003/03L-0.Detailed Event Analysis Encl

ML20071B559
Person / Time
Site:	Oconee
Issue date:	02/18/1983
From:	Tucker H DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20071B560	List: 05000269/LER-1983-003, Forwards LER 83-003/03L-0.Detailed Event Analysis Encl
References
NUDOCS 8302280412
Download: ML20071B559 (2)

LER-2083-003, Forwards LER 83-003/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2692083003R00 - NRC Website

text

1

. g DUKE POWER GOMi%NY P.O.HOx 33180 CHAHLOTTP,. N.O. 28242 HALH. TUCKER ran.gynong 7~*"

,, " ","""L February 18, 1983 (7")

Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II $ L-101 Marietta Street, Suite 3100 m p!p Atlanta, Georgia 30303 Q 'Rd um ?M Re: Oconee '!uclear Station "#-

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Docket No. 50-269 O

3 J i . 7r I

Dear Mr. O'Reilly:

..  ?

e i Please find attached Reportable Occurrence Report RO-269/83-03. This neport -

is submitted pursuant to Oconee Nuclear Station Technical Specification 6.6.2.1.b(1) which concerns engineered safety featured instrument settings found to be less conservative than those established by Technical Specifications ,

but that do not prevent the fulfillment of the functional requirements of the affected system, and describes an incident which is considered to be of no significance with respect to its effect on the health and safety of the public.

Very truly yours, fSb"wjgg Hal B. Tucker JCP/php Attachment cc: Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Mr. J. C. Bryant NRC Resident Inspector Oconee Nuclear Station INPO Records Center Suite 1500 1100 circle 75 Parkway Atlanta, Georgia 30339 Mr. E. L. Conner, Jr.

Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 .,

ON]. '

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%g- gL 8302280412 830218 PDR ADOCK 05000269 S PDR

Duke Power Company Oconee Nuclear Station Report Number: R0-269/83-03

' Report Date: February 18, 1983 Occurrence Date: January 20, 1983 Facility: Oconee Unit 1, Seneca, South Carolina Identification of Occurrence: Engineering Safeguards Reactor Building Pressure ~

Transmitter found out of calibration Conditions Prior to Occurrence: 100% Full Power Description of Occurrence: On January 20, 1983 it was observed that the computer indications for the Unit 1 Engineering Safeguards (ES) Channels A, B, and C Reactor Building narrow range pressure transmitter (RBNRPT) had drif ted out of calibration but had not exceeded the station procedure check limit. The channels were then calibrated to correct the drift. Per a review of the as found data contained in the ES System Reactor Building Narrow Range Pressure Calibration and Analog Channel-Tests, it was determined that the Unit 1 ES Channel A RBNRPT had-drif ted out of calibration and had been non-conservative with respect to Technical Specification 3.5.3.

Apparent Cause of Occurrence: The cause of this incident was a deficiency in procedures. The present procedures require a check of the computer indications every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Calibration is to be requested if any two indications disagree by more than 0.4 psig. All readings observed on January 20, 1983 did not disagree by more than.0.4 psig. Not until the test data were analyzed was it realized that the transmitters were non-conservative. It is apparent from this incident that if all three narrow range RB pressure transmitters drift in the same direction,.

the then present criterion for a calibration check is not adequate.

Analysis of Occurrence: Had a Loss of Coolant Water Accident (LOCA) occurred and had RB pressure significantly increased, ES Channels B and C would have tripped on high RB pressure at less than the Technical Specification required setpoint of 4 psig. The design of the ES system is such that 2 out of 3 channels tripped will cause the appropriate ES functions to occur. Therefore, the ES actions associated with RB pressure of 4 psig would have initiated prior to reaching 4 psig.

ES Channel A would have tripped on high RB pressure'at 4.19 psig. Although the Technical Specification required trip setpoint of 4.0 psig was exceeded, a setting of 4.19 psig did not significantly degrade the Unit 1 ES system. Thus, the health and safety of the public were not compromised by this incident.

Corrective Action: The immediate corrective action was to calibrate the ES Channel A RB narrow range pressure transmitter. It is planned to add a criterion to the RB pressure check so that a transmitter calibration check will be called for if one or more narrow range transmitters are indicating -0.6 psig or a more negative number.