ML19254F918
| ML19254F918 | |
| Person / Time | |
|---|---|
| Site: | Shoreham File:Long Island Lighting Company icon.png |
| Issue date: | 10/22/1979 |
| From: | STONE & WEBSTER ENGINEERING CORP. |
| To: | |
| Shared Package | |
| ML19254F915 | List: |
| References | |
| NUDOCS 7911190402 | |
| Download: ML19254F918 (8) | |
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LOCA/SRV SUEMERGED STRUCTURE ICADS METHODOLOGY October 22, 1979 STONE & WEBSTER 0
1343 337 7 911190 mod
LOCA/SRV SUPJtERCED STRUCTURE LOADS D**D FD l'3 f I.
INTRODUCTIC!
k 3_N eo During a postulated LOCA event or SRV discharco, water clearing, air expulcion and cteam condensation in the Mark II suppression pool will create induced fluid motion which in turn may produce loads on the cubmerged structures. In order to evaluate these hydrodynamic loads, analytical models are utilized to predict velocity and acceleration in the entire flow field. The subsequent calculation of the total drag loads due to both standard and acceleration drag is carried out for each submerged structure as follows: (See DFFR (Ref. 1) and NEDE-21730 (Ref. 2))
Cd ^x (1)
Standard drag =F =
3 2g, C,yV0 (2)
Acceleration drag =F,=
C Vhere Cd = Standard Drag Coefficient A = Stmeture's Area Nomal to the 1 ow Direction f = Vater Density U = Fluid Velocity g = Acceleration Constant e
C = Inertia Coefficient V = Structure Volume
~
= Fluid Acceleration In the process of computing the loads, the NRC Acceptance Criteria (Ref. 3) concerning the unsteady flow effect, interference effect, equivalent uniform flow, bubble asymmetric effect, etc. are addressed and considered whenever they are needed.
The approaches to the calculation of submerged structure loads for Shoreham plant are deceribed in detail below.
II.
LOCA SUBMERGED STRUCTURE LCADS In this section, the methods used to predict the hydrodynamic loads accociated with water jet, air bubble charging, pool cuell, fallback, condencaticn oscillation and chugging in the LOCA event arc discussed.
)bhb A.
LOCA Water Jet Loads Shoreham adopts the NRC Acceptance Criteria to calculate the LOCA water jet loads.
First, the vent clearing transient is determined using Shoreham response to NRC Que:: tion 020.58 part (2).
Based en NEDE-21472 (Ref. 4), DFFR and NEDE-21730, the jet front location, velocity and acceleration are calculated. The potential function from the NRC Acceptance Criteria is used to predict the induced velocity and acceleration in the flow field by the method of NEDE-21471 (Ref. 5). The standard drag and acceleration drag are then calculated in accordance with Eqs (1) & (2). For a structure which is fully engulfed or not fully submerged inside the jet boundary, the procedure outlined la NEDE-21730 is used to calculate the drag forces.
B.
LOCA Air Bubble Charging Loads Based on N70E-21471, NEDE-21730 and DFFR, the air bubble charging loads are calcalated. The following steps are taken to compute the loads:
(1) Uce NEDE-21471 to determine the bubble source strength, the induced velocity and acceleration in the flow field.
(2} Use procedure in NEDE-21730 and DFFR to determine the drag loads.
(3) NRC Acceptance Criteria are addressed according to Ref. 6.
C.
Fool Svell Loads NEDE-21544-p (Ref. 7), DFFR, NEDE-21730 and NRC Acceptance Criteria are used to develop the forcing functions on structures in the pool swell sone. Major steps taken are as follows:
(1) Use NEDE-21544 and DFFR to evaluate the pool water slug velocity, acceleration and elevation time histories.
(2) Use DFFR and NEDE-21730 to calculate the standard drag and acceleration drag loads.
(3).Use NRC Acceptance Criteria (Section III.B.3.C.1) to calculate the impact loads.
(4) Use Ref 6 to address the NRC concerns about lif t force.
D.
Fool Fallback Loads The fallback loads on structures are computed based on the velocity and acceleration timo histories of a free falling fluid slug.
The procedure outlined in DFFR and NEDE-21730 is used to evaluate the fallback loads on structures located between the vent exit and the maximum pool swell height.
gJam E.
Condensation Oscillation Loads Condensation oscillation produces an offective unsteady source at the vent exit analogous to the LOCA air bubble source and can also be expected to generate submerged structure loads.
Once the source strength is defined, the same basic approach and fundamentals that are applied to the LOCA air bubble load calculation can be utilized to compute loads.
Shorcham uses basically the approaches of G.E. documents: NEDO-21669 (Ref. 8), NEDE-23617-P (Ref. 9), 4T Application Memo (Ref.10),
NEDE-21471, DFFR and NEDE-21730 with the following features:
(1) Based on analytical hydrodynamic models in NEDO-21669 and NEDE-23617-P, the source is defined as follows:
(a) A point source is located at each vent (downcomer) tip.
(b) The source strength, S, is derived from full scale single vent data of the 4T test facility, and is related to the wall pressure as follows:
j _ P vall U) 9 f (r)
Where P vall = 4T wall pressure at tank botton center
? = Fluid Density f (r) = Transfer factor detemined by the method of images and 4T geometry.
According to the 4T Application Memo, the bounding wall pressure in Eq. (3) is used. The pressure history is considered to be sinusoidal with an amplitude of +5 psi and a possible frequency range of 2 to 7 Hertz.
(2) After the source strength is defined, the worst combination of phasing (out - of - phase) -for all vents is considered to calculate the submerged structure loads in accordance with the analysis and procedure outlined in NEDE-21471, DFFR and NEDE-21730.
(3)
Interference effect, unsteady flow effect, and equivalent velocity and accolcration are incorporated to comply with NEC Acceptance Criteria.
})kb k
c r..
w rg-y A
F. Chugging Loads D
i Essentially the same methodology used in the load definition for condensation oscillation is adopted to compute the chugging loads.
All documents mentioned in II. E. plus the Shoreham response to NRC Question 020.75 form the design bases for load generatien, The key difference from condensation oscillation is described as follows:
(1) Chug source strength is based on the 4T Applicatien memo with the maximum source being that resulting in the +20 psi, -14 psi amplitude wall pressure. The frequency range used for chugging loads is 20 through 30 Hs.
(2) 'Jhen cencidering the influence of more than one vent, source amplitude is reduced by using a source amplitude multiplier versu.s number of vents function based on the asymmetric wall pressure distribution.
(see Figure 020.75-1)
III. SRV SUBMERGED STRUCTURE LOADS In this scetion, the methodology adopted to predict SRV submerged structure loads related to the water jet and air bubble oscillation is discussed.
A.
SRV Water Jet Loads According to the NRC Acceptance Criteria, the SRV vater jet loads may be neglected for those structures located outside of a sphere circumscribed about the quencher arms.
Shorcham's zone of influenca as defined by the NRC Acceptance Criteria is a sphere with radius of 5.328 f t.
However, as proposed by the Mark II Lead Plant Owners, the zone of influence of SRV water jet is modified from a sphere to a cylinder tangent to the sphere.
Although the jet loads are expected to be small, the.. loads on structures inside the modified cylinder zone of influence are calculated as follows:
(1) Standard drag is calculated frem NEDE-23539 (Ref.11) and NEDE-25090-P (Ref. 12)
(2) The induced acceleration is ' predicted by the line cource method (Ref. 13) The subsequent acceleration drag computation is obtained from DFFR and NEDE-21730.
B.
SRV Air Bubble Loads Shoreham uses a NRC/KWU hybrid method. This methodology includes the follouing features:
(1) HRC Acceptanco Criteria n,
Assume air bubble with radius of 5 foot located at quencher center.
1343 341
_4_
b.
Use Mark II submerged structure load calculation methodology in NEDE-21471, DFFR and NEDE-21730, c.
Fulfill the NRC required modifications, such as bubble asymmetric effect, interference effect, etc.
(2) Single exception to the NRC Acceptance Criteria:
use KWU specification (Ref.14) to define the bubble pressure, i.e. bubble pressure is equal to 1.5 KKB (3 KVU-PPL pressure traces)
(3) Application a.
Source strengh is based on the product of bubble radius (5 f t.) and pressure (1.5 KKB) b.
Frequency range is covered by using a time scale factor of 0.8 to 1.8 on KVU pressure time histories.
Vorst frequency is considered for the structure
- loads, c.
Use analysis and precedure in NEDE-21471, DFFR and NEDE-21730 to calculate the submerged structure loads.
IV. REFERENCE 1.
" Mark II Containment Dynamic Forcing Functions Information Report (DFFR)," NED0-21061-P, NEDD-21061, Revision 3, Class 1, June 1978, (GE Report)
"M rk II Pressure Suppression Containment System Loads on 2.
a Submerced Structures - An Application Memorandum," NEDE-21730, December 1977. (GE Report) 3.
" Mark II Containment Lead Plant Program Lead Evaluation Report,"
USNRC, NUREG-0487, October 1978.
4.
" Analytical Model for Liquid Jet Properties for Predicting Forces Rigid Submerged Structures," NEDE-21472, Sept.1977. (GE Report) on 5.
" Analytical Model for Esticating Drag Forces on Rigid Submerged Structures Caused by LCCA and Safety Valve Ramshead Air Discharge,"
GE Report, NEDE-21471, Sept. 1977.
6.
"Draf t Report on Submerged Structure Methodology in Response to the NRC Submerged Structure Acceptance Criteria for Mark II Lead Plants," Submitted to the NRC in May 1979, on Zimmer Docket.
7.
" Mark II Pressure Suppression Containment System: An Analytical Model of the Pool Suc11 Phenomenon," CE Report NEDE-21544-P, December 1976 47 7A7
)b4J J4L
8.
"The Multivent Hydrodynamic Model for Calculating Pool Boundary Loads Due to Chugging - l'. ark II Containments," GE Report NEDE-21669, June 1977.
- 9. ' " Mark II Lead Plant Topical Report Pool Boundary and Main Vent Chugging Loads Justification," GE Report NEDE-23617-P, July 1977.
10.
" Mark II Phase I, II and III Temporary Tall. Tank Test Application Memorandum," Janaery 1977, Letter from L.J. Sobon (G.E.) to 0. Parr (NRC) 11.
" Analytical Model for Quencher Vater Jet Loads on Rigid Submerged Structures," GE Report NEDE-23539-P, Class III, August 1979 (Draf t) 12.
" Analytical Model for T-Quencher Vater Jet Loads on Submerged Structures," GE Report NEDE-25090-P, Class III, May 1979
- 13. Shames, I.H., " Mechanics of Fluids," McGraw-Hill Book Company, 1962 14 "Thermo-Hydraulic Quencher Design of the Safety Relief System,"
Kraftwerk Union Report R1/.-25/1978, Revision 1, April 1978 9
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. 1343 343
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