ML17266A211

RO 335-80-27:on 800514,C-E Informed Util That Partial Draining of RCS While in Mode 5 Is Condition Not Analyzed for Boron Dilution Event.Plant Operating Procedures Revised to Increase Shutdown Margin

ML17266A211
Person / Time
Site:	Saint Lucie
Issue date:	05/15/1980
From:	Wethy C FLORIDA POWER & LIGHT CO.
To:
References
987, NUDOCS 8006050325
Download: ML17266A211 (2)

Text

CMW-PSL POST OFFICE Y 128, FT. PIERCE, FLORIDA 33450 Ltr. Bk. i/ 987 //g Copies to: CMW, JHR, CAW, GMV, RRJ rgsi Offsite: ADS, JRB, COW, MAS, REU, KNH FLORIDA POWER & LIGHT COMPANY To: Mr. J. P. O'Reilly, Director Region II Office of Inspection and Enforcement May 15, 1980

"'. S. Nuclear Regulatory Commission Atlanta, Georgia 30303 From: Mr. C. M. Wethy, Plant Manager St. Lucie Plant DPR 67 Florida Power 6 Light Company Miami, Florida

Subject:

MEMO FOR FACSIMILE TRANSMISSION TO CONFIRM 10 CFR PART 21 PROMPT REPORTABLE OCCURRENCE 335-80-27 Operation in Mode 5 with partially drained Reactor Coolant System.

This memo is to confirm a telephone call on May 14, 1980 to Mr. Steve Elrod of your office.

Event: On May 14, 1980, Florida Power and Light was informed by the St. Lucie Unit 1 NSSS supplier, Combustion Engineering, that partial draining of St. Lucie 1 type Reactor Coolant Systems while in Mode 5 is a condition that has not been analyzed for the boron dilution event. The effect of the reduced RCS volume on Combustion Engineering's analysis would be a predicted time to criticality that is less than the minimum time period for operator action, assuming no more than the Technical Specification (T.S. 3.1.1.2) shutdown margin of 1% Ap existed at the onset of the event.

Corrective Action:

In accordance with the NSSS supplier's recommendations, Florida Power & Light has revised plant operating procedures to:

a) increase the shutdown margin when partially drained in mode 5 by an additional 1% Ap above the existing Tech Spec required shutdown margin of 1% Ap, ensuring at least 20 minutes to elapse before criticality, and b) preclude operation with more than two charging pumps running while in mode 5.

PooO C. M. Wethy Plant Manager St. Lucie Plant i/o CMW/BMP:esr "H "I sh Q 'QQpg 80060503g p PEOPLE... SERVING PEOPLE

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