ML20038B313

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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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7 klJ.,1 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

Reference:

GESSAR II, 238 Nuclear Island, 22A O,

033180, Appendix 3B - Mark III containment Loads

Dear Professor Plesset:

Mark III Vent Chugging Loads are specified in a form of pressure pulses in vents.

Load specification assumes that the chugging 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

[H (t-

)f (r t-h)

P (r, t)

=

i, i

i=1 where r is the distance of point P from t.he v'ent i, v is the g

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

/G

f 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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