ML19269C920

Informs NRC of Professor Plesset'S Subcommittee Discussion at San Francisco Meeting Re LOCA-related Hydrodynamic Loads. Stated Vent Lateral Loads Due to Steam Condensation Were Random in Magnitude & Direction

ML19269C920
Person / Time
Site:	Zimmer
Issue date:	12/18/1978
From:	Catton I CALIFORNIA, UNIV. OF, LOS ANGELES, CA
To:	Savio R Advisory Committee on Reactor Safeguards
References
ACRS-CT-1079, NUDOCS 7902210152
Download: ML19269C920 (1)

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Boelter Hall 2567 University of California Los Angeles, California 90024 December 18, 1978 To: Dr. R. Savio b [- / O 7 From: Ivan Catton / M/I E// .,

Subject:

Zimmer Nuclear Power Plant Copics To: S. Duraiswamy and A. Bates At the San Francisco meeting of Professor Plesset's subcommittee (Fluid Dynamic Effects) LOCA - Related hydrodynamic loads were discussed. In particular, it was stated that vent lateral loads due to steam condensation were random in magnitude and direction, see page 377 of the meeting trans-cript. It is assumed that the loads are applied to all the vents simultan-cously.

The assumption of simultaneous application is clearly conservative under some circumstances. From the meeting, see page 381, lines 11-13 I was left with the feeling that a statistical analysis of the multiple vent data had not been carried out. It seems to me that before a Monte Carlo method (page 379) can be used with confidence, one must demonstrate the random nature of the phenomena (direction and magnitude). It is my opinion that this has not been done. It is difficult to assess whether the assump-tion of simultaneous application of the loads on all vents has enough conservatism to accommodate the lack of conservatism associated with the possibility that the forces due to chugs may not be random in direction and magnitude.

IC/li R'

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