ML19254H091

Safety Evaluation Suppl Re Containment Overpressurization Potential Due to Auxiliary Feedwater Pump Runout Flow Following Main Steam Line Break.Peak Containment Pressure Will Remain Below Design Pressure

ML19254H091
Person / Time
Site:	05000000, Calvert Cliffs
Issue date:	05/15/1980
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
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References
FOIA-80-515, FOIA-80-555 NUDOCS 8005290552
Download: ML19254H091 (1)

Text

4 CALVERT CLIFFS tiUCLEAR POWER PLAT!T, Ut!ITS 1 At1D 2 SER Supplement Docket tios. 50-317, -318 C0tiTAlt#EtiT OVERPRESSURIZATION F0TEtiTIAL DUE TO AUXILIARY FEEDWATER PUMP rut!-0VT FLOW FOLLOWIt4G A MAlti STEAM lit 1E BREAK By letter dated December 21, 1979, the staff requested Baltimore Gas and Electric Company, the licensee for the Calvert Cliffs fluclear Plant, Units 1 and 2 to pro-vide certain additional information.

Specifically, the licensee was to assess the potential for containment overpressurization due to the anticipated continuous addition, at pump's run-out flow, of auxiliary feedwater to the affected steam gen-erator following a postulated main steam line break (MSLB) accident.

The staff's interest in this issue resulted from the recommendation of the Three Mile Islar.d, Unit 2 (TMI-2) Lessons Learned Task Force to automate initiation of the auxiliary feedwater systems. Automating the auxilia y feedwater system would cause an increase in energy released to containment after a MSLB; thereby, increas-ing the containment pressure response to a MSLB.

In a letter dated January 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 aux-iliary feedwater pump run-out. The licensee has performed an analysis that demon-strates that the addition of auxiliary feedwater at the run-out flow condition (2200 cpa) will not cause containment pressure to rise above the initial blowdown peak. The auxiliary feedwater pump run-out flow was based on a backpressure of one atmosphere.

The staff concurs with the licensee's conclusion that the peak containment pres-sure will remain below the containment design pressure even with the addition of auxiliary feedwater at the run-out flow rate.

Enclosure 8005290 h