ML20069L077

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Final Deficiency Rept Re Potential Low Suction Pressure Due to Bam Sys Safety Injection Actuation Signal Pump Start Logic.Initially Reported on 830318.Control Logic Modified
ML20069L077
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 04/18/1983
From: Robert E. Uhrig
FLORIDA POWER & LIGHT CO.
To: James O'Reilly
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8304280028
Download: ML20069L077 (2)


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FLORIDA POWER & LIGHT COMPANY 83 APR 25 nI(), p ,

April 18, 1983 L-83-243 Mr. James P. O'Reilly Regional Administrator, Region II U. S. Nuclear Regulatory Commission 101 Marier.ta Street, Suite 2900 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

RE: St. Lucie Unit 2 Docket No. 50-389 /50.55(e)83-006 BAM System SIAS Pump Start Logic on March 18, 1983 Florida Power & Light Company notified NRC, Region II of a potential 10 CFR 50.55(e) condition existing at the site involving BAM System SIAS Pump Start Logic.

~ Pursuant to the requirements of 10 CFR 50.55(e), a final report is attached.

Very truly yours,

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Robert E. Uhri Vice President Advanced Systems and Technology pCOY'.

8304260028 830418 (WN DR ADOCK 05000 PEOPLE. . SERVING PEOPLE

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SUMMARY

During Safeguards testing the Boric Acid Make-up (BAM) pumps were automatically started, through.the Safety Injection Actuation Signal (SIAS), with offsite power available. Because of their present design logic, the BAM pumps started five (5) minutes af ter initiation of the SIAS. Such' operation could create a low suction condition on the charging pumps, if the boric acid gravity feed valves had failed to open, and thus causing the charging pumps to trip.

II. DESCRIPTION The Boric Acid Make-up pumps and the Boric Acid gravity feed valves provide borated water to the suction of the charging pumps, bypassing the Volume Control Tank. The boric acid gravity feed valves provide a source of suction redundant to the BAM pumps. In order to correct the situation described under " Summary", the BAM pumps are required to follow the charging pumps logic, which start immediately on SIAS with offsite power available and five (5) minutes after SIAS actuation on loss of offsite power.

III. CORRECTIVE ACTION The control logic for the BAM pumps has been modifi,ed, via DCN's .

513.2518 and 513.2648 to follow the charging pumps logic, ie, the BAM pumps will now start together with the charging pumps-immediately on SIAS actuation with off site power available and will start five (5) minutes after.SIAS actuation on loss of offsite power.

IV. SAFETY IMPLICATION Delayed start of the BAM pumps, five (5) minutes on SIAS actuation with offsite power available, could create a low suction pressure condition on the charging pumps, if the boric acid gravity feed valves fail-to open. This low suction pressure condition could trip the charging pumps, preventing boric acid injection on SIAS, and hence loss of boric acid injection into the primary loop of the reactor.

V. CONCLUSION With the above mentioned corrective action, this item is resolved and l

l this item closed regarding 10 CFR 50.55(e) reporting requirements. All pertinent documentation regarding this concern will be maintained at the site, i

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