ML20235D492
| ML20235D492 | |
| Person / Time | |
|---|---|
| Issue date: | 01/15/1975 |
| From: | Tedesco R NRC |
| To: | Gyoreg G GENERAL ELECTRIC CO. |
| Shared Package | |
| ML20234E460 | List:
|
| References | |
| FOIA-87-40 NUDOCS 8707100191 | |
| Download: ML20235D492 (2) | |
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UNITED STATES
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ATOMIC ENERGY COMMISSION
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%ie JAN 151975 975 JAH 16 m 12 5 Geza L. Gyores, Manager BWR Licensing .. nY COMM.
Nuclear Energy General Electric Division Company gtAC 3 Sd[ TOR SArgGUARDSy'cb0MilEE OH 175 Curtner Avenue ..
San Jose, California 95114
Dear Mr. Gyores:
Your letter of December 9,1974 provided a description of an analytical model to calculate the depressurization of a Mark III containment based on the assumption of inadvertent containment spray operation with the containment at an initially low relative huisidity. This information was requested by us at our meeting held on October 9 and 10,1974. The significance of this postulated event is that a driving force would exist following spray actuation to saturate the containment atmosphere by mass transfer of spray water to the vapor phase. This evaporation would be sustained by removal of energy from the containment air thereby decreasing its temperature and partial pressure. Depending on the rate of evaporative ;
cooling, this event could result in the controlling depressurization rate for Mark'III containment vacuum relief design. As you are aware, the containment vacuum relief requirements for GESSAR and other plants utilizing the Mark III containment are currently unresolved review issues.
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We have reviewed your assumptions and f6rmulations of equations used to analyze this event. As a result we find that your analysis apparently does not account for mass transfer of spray water to the vapor phase.
Examination of equations A-12 and A-63 in your Dec, ember 9 letter, show that energy is removed from the containment atmosphere only to bring the temperature of the spray wat'er up to saturation (i.e. , no evaporation) and that the mass of vapor in the containment atmosphere is affected only by vacuum breaker flows (i.e. , no mass transfer from the spray water).
Based on these def t'ciencies we conclude that your analytical model, as
. described in the December 9,1974 letter, is not adequate for use in calculating containment depressurization due to evaporative cooling. We believe that additional efforts should be undertaken to develop a suitable analytical. tool which will calculate the transient mass transfer of spray water to the vapor phase. Should you have any questions regarding our m
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.Mr. Geza L.' Gyoreg 2-JAM 15 5 r; valuation of your analytical model, please contact me or Mr. Robert I Cudlin. Since this matter is directly concerned with the final sizing of the vacuum breakers, we believe that early resolution should be achieved.
Q& c 'SL$ a Robert L. Tedesco, Assistant Director for Containment Safety Directorate of Licensing cc: Mr. L. S. Gifford Suite 1107 General Electric Company 4720 Montgomery Lane Bethesda, Md. 20014 6
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