L-76-247, Letter Attaching Reportable Occurrence No. 335-B-76-02 Failure to Determine Condenser Delta T.

Letter Attaching Reportable Occurrence No. 335-B-76-02 Failure to Determine Condenser Delta T.

ML18088A940
Person / Time
Site:	Saint Lucie
Issue date:	07/07/1976
From:	Robert E. Uhrig Florida Power & Light Co
To:	Volgenau E NRC/IE
References
335-B-76-02, L-76-247
Download: ML18088A940 (5)

Text

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3 FLORIDA POWER 5 LIGHT COMPANY July 7, 1976 L-76-247 Ernst Volgenau, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Dear Mr. Volgenau:

Re: REPORTABLE OCCURRENCE NO. 335-B-76-02 ST. LUCIE UNIT NO. 1 DATE OF OCCURRENCE: June 9, 1976 "FAILURE TO DETERMINE CONDENSER bT" The attached Non-Routine Environmental Operating Report is being submitted in accordance with Technical Specifi-cat'ion 5.6.2.a.2 to provide 30-day notification of the subject occurrence.

Very truly yours, Robert E. I'Ihrig O Vice President REU/JPF/hlc Attachment cc: Norman C. Moseley, Region II, (2)

Jack R. Newman, Esp.

HELPING BUILD FLORIDA

~ s ST. LUCIE UNIT NO. 1 REPORTABLE OCCURRENCE NO. 335-8-76-02'FAILURE TO DETER1INE CONDENSER AT" DATE OF OCCURRENCE: JUNE 9, 1976 On June 9, 1976, the TR 21-3 recorder in the Control Room which measures the intake and discharge temperatures across the condenser malfunctioned.

This recorder is used to determine the 5T across the condenser hourly as required in Section 2.1.2 of the Appendix B Technical Specifications. The outage of this instrument resulted in missed hourly hT determinations, there-fore a violation of Technical Specifications., The TR 21-3 recorder was out of service from 8:00 a.m. 11:15 a.m. June 9, and from 4:00 p.m; June 9 until 7:30'.m. June ll, a total of 54 hours6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br />.

~Anal sis:

During the TR 21-3 instrument outage twenty-two AT readings were determined from the Inmet Computer which digitally displays and records on magnetic tape the intake and discharge canal temperatures. However, at 4:00 p.m.,

June 10, the discharge canal temperature display on the Inmet malfunctioned and was out of service until ll:00 a.m. June ll. During this time frame, with both the TR 21-3 recorder and Inmet out, no hT readings were determined.

Evaluation:

Of the 54 hour6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br /> outage time of the TR 21-3 recorder, 32 hourly hT determina-tions were not performed. The missing data is retrievable, since the intake'anal temperatures were continuously recorded on magne-if necessaryg tic tape by the Inmet and the discharge canal temperatures were recorded on the strip chart discharge canal temperature monitoring back-up system.

Since there was no change in power level (50%) during the instrument outage time, no reduction in circulating water flow, and since the hT determina-tions from the Inmet system have generally been more conservative (i.e.

higher) than those from the TR 21-3, it is believed that no violation of the 24'F condenser bT rise limit occurred. However, not determining the hT across the condenser hourly, as per Section 2.1.2 of the Appendix B Technical Specifications is a violation in and by itself.

B.- Cause:

See Analysis above.

C. Corrective Action:

A.proposal for a new system to monitor hT across the condenser is presently being reviewed. This new system will then serve as the primary system with the present system serving as a backup. When this new system is installed, the above described situation should not reoccur. Until this modification is completed, local temperature indicators are being installed to be read by the operator whenever the recorder fails. This will prevent another violation of this type.