ML20054M297

Analytical Model for Estimating Drag Forces of Rigid Submerged Structures Caused by LOCA & Safety Relief Valve Ramshead Air Discharges,Suppl for X-Quencher Air Discharges.

ML20054M297
Person / Time
Site:	05000447
Issue date:	10/31/1979
From:	Lasher L, Rogers A, Townsend H GENERAL ELECTRIC CO.
To:
Shared Package
ML20054M237	List: ML20054M236 ML20054M297
References
79NED99R, NEDO-21471-01, NEDO-21471-01-S01, NEDO-21471-1, NEDO-21471-1-S1, NUDOCS 8207120253
Download: ML20054M297 (11)

Text

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Supplement 1 October 1979 .

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ANALYTICAL MODEL FOR ESTIMATING DRAG FORCES ON RIGID SUBMERGED STRUCTURES SUPPLEMENT FOR X-QUENCHER AIR DISCHARGES L E. LASHEH i

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NED0-21471-01 78NED99R Supplement 1 Class 1 October 1979 ANALYTICAL MODEL FOR ESTIMATING DRAG FORCES ON RIGID SUBMERGED STRUCTURES CAUSED BY LOCA AND SAFETY RELIEF VALVE RAMSHEAD AIR DISCHARGES SUPPLEMENT FOR X-QUENCHER AIR DISCHARGES L. E. Lasher Reviewed:

H. E. Townsend, Manager Containment Methods Approved:

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A. E. Rogers, Manager Containment Tech ology Approved: p n,s / ~ ,u ,

J. Jacobson, Manager Reactor and Containment Design

DISCLAIMER OF RESPONSIBILITY I

Neither the General Electric Company nor any of the contributors to this document makes any warranty or-representation (express or implied) with respect to the accuracy, completeness, or usefulness of the information contained in this document or that the use of such information may not infrinae privately owned. rights; nor do they assume any responsibility for liability or damage of any kind wich m:y result from the use of any of the information contained, in this document.

NED0-21471-01 CONTENTS l t

PAGE ABSTRACT y

1. INTRODUCTION 1

2. MAJOR ASSUMPTIONS 2

3.

SUMMARY

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NED0-21471-01 ILLUSTRATIONS FIGURE TITLE PAGE

1. Schematic of the Four-Bubble Model for X-Quencher Air Discharge 4 iv

fled 0-21471-01 ABSTRACT The discharge of air from a quencher will induce an unsteady water motion in'the suppression pool due to air bubble oscillation and create forces on submerged structures. This supplement provides a method for estimation these forces on the basis of an analytical model developed for spherical bubbles.

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NED0-21471-01 l

1. INTRODUCTION Following a safety relief valve (SRV) discharge from an X-quenche'r, the oscillating air bubbles formed by the discharge result in fluid drag loads on structures submerged in the suppression pool. The total fluid loading is composed of an acceleration-drag component and a standard-drag component.

The methods of estimating the acceleration drag and standard drag developed for the ramshead air discharges in the basic report of this supplement also apply to the air bubbles exiting an X-quencher. It is assumed that four identical air bubbles oscillating in phase are formed between each pair of arms of an X-quencher (see Figure 1).

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2. MAJOR ASSUMPT13NS

1. Those assumptions concerning oscillating bubbles made in Section 2

-of the basic report are also applicable to this supplement. The same bubble-dynamics equations given for air bubbles from ramshead SRV d.ischarge devices satisfy the essentials for air bubbles from X-quencher discharge devices. j l

2. It is assumed that four identical spherical bubbles oscillating in

! phase are formed in an X-quencher, one between each pair of arms. This assumption is supported by the following facts: -

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a. The hole pattern in the quencher arm forces the water preceding the steam-air mixture to flow toward the space between the arms.

The steam-air mixture following the water is carried in the same direction. Rapid expansion of the mixture leads to coalescence of the small streams into one big bubble between each pair of arms.

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b. Movies taken of discharges from perforated pipes show the formation of one big bubble around a cluster of holes. They clearly indicate the rapid coalescence of the streams into one big bubble.

c. Observations from film ctudies of scaled X-quencher tests show the formation of four spherical bubbles, one between each pair of arms.

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3.

SUMMARY

The calculations carried out for X-quencher air bubbles are identical to those described in Section 3 of the basic report on ramshead air bubble discharges. Equation A80 may be used in the case when the four quencher bubbles from the same SRV line are considered to be synchronously fonned and of equal strength.

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! I SIDE VIEW Figure 1. Schematic of the Four-Bubble Model for X-Quencher Air Discharge 4

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