ML20038B313

Discusses Mark III Vent Chugging Loads.Specifying Various Vents Chugging Simultaneously,Addition of Individual Vent Contributions to Pressure at Specific Location Should Consider Differences in Pressure Pulse Arrival Time

ML20038B313
Person / Time
Site:	05000447
Issue date:	10/08/1981
From:	Zudans Z FRANKLIN INSTITUTE
To:	Plesset M Advisory Committee on Reactor Safeguards
References
ACRS-CT-1383, NUDOCS 8112070587
Download: ML20038B313 (2)

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-[ . 00.Franklin Research Center Fx A Division of The Franklin Institute / #pg OS!6 MuS October 8,-1 85

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I k klJ.,1 - 7 Professor Milton S. Plesset -

Department of Engineering Science i NOV2 01981> C3 California Institute of Technology Pasadena, California i

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Subject:

Mark III Chugging Loads th O,

Reference:

GESSAR II, 238 Nuclear Island, 22A .

033180, Appendix 3B - Mark III containment Loads

Dear Professor Plesset:

Mark III Vent Chugging Loads are specified in a form of pressure Load specification assumes that the chugging pulses in vents.

loads transmitted to drywell wall, weir wall, basemat, and contain-ment are the result of several vents chugging simultaneously at different amplitudes. Chug amplitude spatial attenuation is allowed, both in cross section of the pool as well as circum-ferentially. The attenuation of peaks is based on observed pressure .

at locations away from the chugging vent (approximately inversely proportional to the distance from the source) .

I have no comments to the attenuation argument. However, specifying various vents chugging simultaneously the addition od individual vent contributions to the pressure at a location P should consider the differences in the pressure pulse arrival time from individual chugging vents. Pressure history at a location P should be defined by a function of the form N r i

P (r , t) =

[H (t-i=1

)f (r i, t-h) where r g is the distance of point P from t.he v'ent i, v is the pressure wave propagation velocity, f (r,T) is the attenuation i

! and time variation function of the pulse, H (T ) is Heaviside step function having value of 1 at T >0, and M is the total number of vents considered. ,

8112070587 811oog PDR ACRS -

CT-1383 PDR The Benjamin Franklin Parkway, Philadelphia, Pa.19103 (215)448 1000 TWX-710 6701889

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, Professor Milton S. Plesset October 8, 1981 If the arrival time differences are not taken into account unjustified conservatism may be introduced.

Very truly yours, W~

Zenons Zudans ces Senior Vice President cc: P. Boehnert e

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