ML20027B835

Forwards LER 82-011/03L-0.Detailed Event Analysis Encl

ML20027B835
Person / Time
Site:	Oconee
Issue date:	09/21/1982
From:	Tucker H DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20027B836	List: ML20027B835 ML20027B839
References
NUDOCS 8209300183
Download: ML20027B835 (3)

Text

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~ *m , y DUKE POWER COMPANY P.O. BOK 33180 GHAMLOTrE, N.C. 28242 H AL H. TUCKER MuP*N vws rammiocat NM UNE a====== September 21, 1982 Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 .

Atlanta, Georgia 30303 ro Lc w ro Re: Oconee Nuclear Statio" Docket No. 50-270 Q

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Dear Mr. O'Reilly:

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-- m3 Please find attached Reportable Occurrence Report R0-270/82-11. This rep rt [,{ 2 is submitted pursuant to Oconee Nuclear Station Technical Specification Q .2.1 &t2) which concerns operation in a degraded mode permitted by a limiting condition g --

for operation, and describes an incident which is considered to be of no sig-nificance with respect to its effect on the health and safety of the public. .

Very truly yours, d

Hal B. Tucker JCP/php I.ttachment cc: Document Control Desk Mr. Philip C. Wagner U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. 20555 U. S. Nuclear Regulatory Commission Washington, D. C. 20555 INP0 Records Center Mr. W. T. Orders Suite 1500 NRC Resident Inspector 1100 Circle 75 Parkway Oconee Nuclear Station Atlanta, Georgia 30339

/gpylC 8209300183 820921 PDR ADOCK 05000270 S PDR T84%

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Duke Power Company Oconee Nuclear Station Report Number: R0-270/82- 14 Report Date: September 21, 1982 Occurrence Date: August 22, 1982 Facility: Oconee Unit 2, Seneca, South Carolina Identification of Occurrence: Boiling Water Storage Tank (BWST) level instrument Channel "A" was declared inoperable due to erratic readings.

Conditions Prior to Occurrence: 100% Full Power Description of Occurrence:

At 1500 on August 22, 1982, Control Room personnel on Unit 2 received a high level statalarm on Unit 28s BWST. The level instrumentation was checked and Channel "A" was found to be operating erratically. At that time the level indication for Channel "A" was declared inoperable and a 24-hour Technical Specification time limit was imposed (Technical Specification 3.3.4). A work report was written to investigate the problem. The cause was found, and the corrective action was performed to have the system working properly within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Apparent Cause of Occurrence:

The investigation revealed boiling water in the input line to the level trans-mitter, 2LT-6. This resulted in steam in 2LT-6 which caused the erratic operation.

Further investigation revealed a broken thermostat which was causing the heat tracing to be on continuously, thus overheating the input line water.

Analysis of Occurrence:

BWST Channel "B" was operable while BWST Channel "A" was out of service. The water level in the BWST was maintained within Technical Specification limits at all times, thus ensuring an adequate supply for emergency injection. There-fore, the health and safety of the public were not endangered.

Corrective Action:

The immediate corrective action was to secure the heat tracing and refill the transmitter lines with water. Level indication was restored. Heat tracing was not necessary at that time due to the ambient temperature being much greater than the temperature required for freezing the water or crystallization of the Boron in the water (Both %32 F). The thermostat was found broken and was replaced, and the heat tracing is now operating properly. I er the heat tracing was secured and after it was later replaced, the le cending for Channel "A" corresponded to the level reading for Channel ' o

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Report Number R0-270/82-14 Page 2-After reviewing previous incident reports, it was found that this is the first occurrence of a~ broken thermostat causing erratic-BWST level indication.

Therefore, since this is apparently a random failure, no further corrective action is required.

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