ML19254H090
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,f b '.M L/.i L 2 2 tit VAY 15 G80 Docket Nos. 50-317. -318 MEM0PA'iDUM FOR:
T. Novak, Assistant Director for Operating Reactors, DL FRO'i:
L. Rubenstein, Assistant Director for Reactor Systems, DSI
SUBJECT:
STAFF EVALUATION OF CALVERT CLIFFS, UNITS 1 A'!D 2 RE:
CONTAINMENT OVER-PRESSURIZATION POTENTIAL DUE TO AUXILIARY FEEDWATER PJMP RUN-CUT FLOU FOLLOUING A MSLB By letter cfated December 21, 1979, the staff requested Baltimore Gas and Elec-tric Company, the licensee for the Calvert Cliffs Nuclear Power Plant, Units 1 and 2, to provide certain additional infomation.
Specifically, the 1f-ensee was to assess the potential for containment overpressurization due to be an-ticipated continuous addition, at pump's run-out flow, of auxiliary fee bar to the affected steam generator following a postulated main steam line areak (MSLB) accident.
The staff's interest in this issue resulted from the recomendation of the Three Mile Island, Unit 2 (TMI-2) Lessons Learned Task Force to automate initiG ation 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 MSLB.
By letter dated Jany'ary 25, 1980, the Baltimore Gas and Electric Company re-sponded to the staff's letter cited above.
In the original MSLB analysis by the licensee, no consideration was given to auxiliary feedwater pup run-out. The licensee has since perfonned an analfsis that demonstrates that the addition of auxiliary feedwater at the run-out flow condition will not cause containment pressure to rise above the initial blow-down peak.
The staff concurs with the licensee's finding that the peak containment pressure will remain below the containment design pressure with the addition of auxiliary feedwater at run-out flow. 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 conside'td the consequences of postulated single failures such as failure of the main feedwater control valve to close. To satisfy current criteria, the MSLB accident should be re-analyzed w ntaci::
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MAY 151980 T. llovak assuming single fative failures. '!e suggest that you may wish to have the licensee reanalyze the containment response transient in a manner consistent with current criteria at an appropriate time.
Origina' signed by L. S. Aubenstein Lester S. Rubenstein, Assistant Director for Reactor Systems Division of Systems Intearation
Enclosure:
As stated cc:
R. Clark E. Conner
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- 14. Butler J. Shapaker P. Hearn Central files CSB Rdg NRR Rdg LRubenstein f
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DU.5 GCVE AN=*EN' an catiNo cariCE: 1979-289-363