ML17208A670
Text
Docket No.60-335 MEMORANDUM FOR:
T. Novak, Assistant Director for Operating Reactors, DL FROM:
SUBJECT:
L. Rubenstein, Assistant Director for Reactor Systems, DSI STAFF EVALUATION OF ST. LUCIE, UNIT 1 RE:
CONTAINMENT OVER-PRESSURIZATION POTENTIAL DUE TO AUXILIARYFEEDMATER PUMP RUN-OUT FLON FOLLOWING A MSLB By letter dated December 21, 1979, the staff requested the Florida Power and Light Company (FPSL), the licensee for the St, Lucie Nuclear Power Plant, Unit 1 to provide certain additional information.
Specifically, the licensee was to as-sess the potential for containment overpressurization due to the anticipated con-tinuous addition, at pump run-out flow, of auxiliary feedwater to the affected steam generator following a postulated main steam line break (MSLB) accident.
The staff's interest in this issue resulted from the recommendation of the Three Mile Island, Unit 2 (TMI-2) Lessons Learned Task Force to automate initiation of the auxiliary feedwater systems.
Automating the auxiliary feedwater system would cause an increase in energy released to containment after a MSLB; thereby.
increasing the containment pressure response to a HSLB.
By letter dated January 24, 1980, the Florida Power and Light Company responded to the staff's letter cited above.
In the original MSLB analysis by FP8L, no consideration was given to auxiliary feedwater pump runout.
The licensee has since performed an analysis that demon-strates that the addition of auxiliary feedwater at the run-out flow condition will not cause containment pressure to rise, above the initial blowdown peak.
The staff concurs with the licensee's finding that the peak containment pressure will remain below the containment design pressure even with the addi.tion of auxili-ary feedwater at run-out f'low.
An SER on this matter was prepared by the Contain-ment Systems Branch and is enclosed.
In the course of our review of the postulated MSLB with auxiliary feedwater pump run-out, we noted that the licensee had-not considered the consequences of pos-tulated single failures such as failure of the main feedwater control valve to close.
To satisfy current criteria, the MSLB accident should be re-analyzed
Contact:
P. Hearn, CSB:DSI 27064 OFFICE,$
SURNAME OATEN..
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%AH MAY 15 1980 T. Novak assuming single active failures.
ate suggest that you may wish to have the lice@see reanalyze the containment response transient in a manner consistent Mith current criteria at an appropriate time.
Enclosure:
As stated'c:
P. Erickson R. Acid
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