ML19322B612
| ML19322B612 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/14/1975 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19322B610 | List: |
| References | |
| NUDOCS 7912040638 | |
| Download: ML19322B612 (3) | |
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REACTOR VESSEL SUPPORT EVALUATION FOR LOCA LOADINGS For loss of coolant conditions, the dynamic response of the reactor vessel This supports was analyzed using the discrete planar model shown in Figure 1.
model was devised for the idealizedstructure shown in Figure 2.
The shells were represented by flexible, massless beam elements having the cross-sectional area, moment of inertia, etc. of uniform, constant-thickness An additional rotational spring at the base of the model repre-cylinders.
sented the flexibility of the vessel foundation.
In general, masses were placed at points of concentration of weight in the actual structure.
The reactor vessel is represented by masses 1, 2, and 3.
Mass 1 includes the lower vessel head, enclosed water, and a portion weight of the vessel skirt, Mass 2, located at the elevation of the nozzles, includes of the vessel shell.
the weight of the central portion of the vessel shell, enclosed water, the Mass 3 re-plenum cover, and a portion of the core support structure shells.
presents the upper vessel head, enclosed water, and drive nozzles.
Mass 4 is located The reactor internals are represented by masses 4, 5, and 18.
the upper grid and includes the weight of the grid, plenum cylinder, and at Mass 5, at the lower grid elevation, represents about 2/3 the 1/8 of the core.
weight of the core support structure; the remainder is included in Mass 2.
Mass 18 is the concentrated weight of the lower grid and flow distributor, plus 1/8 of the core.
The entire core was modeled as a simply-supported beam having the natural fre-quency of a single fuel assembly (about 3 cps). Masses 6, 7, and 8 each re-present 1/4 core weight. The other 1/4 core weight is divided between masses 4 and 18.
Masses 9 through 12 represent the distributed weight of the drive support structures (a cylinder bolted to the vessel head providing lateral support for the upper ends of the control rod drives).
Mass 13 is The control and drives are represented by masses 13 through 17.Mass 14 re-located at the fringe between the core nozzle and the drive.
Masses 15, 16, and 17 represent the distributed presents the drive motors.
weight of the drives and drive housings.
To evaluate the postulated LOCA condition, the applied thrust due to a pipe rupture was applied to the model in the form of a thrust versus time curve.
The LOCA thrust force acting at the reactor vessel's outlet nozzle was analyzed using the FLASH computer code and the relationship, thrust = pressure x area.
A structural dynamics computer code was utilized to calculate the dynamic res-ponse of the planar model, i.e., the displacements, velocities, accelerations, and ef fective static forces at each time step. The time-varying effective static forces were then used to determine the foundation loads.
7912040638
l FIGURE 1 REACTOR VISSEL DY!!AlilC 10 DEL 12 R
17 C=
=O I
()1 h{}16 C0llTROL ROD DRIVE St"'"3RT DRIVES k
STRUCTU 010 b()ls
)9 t
/
9 4
K
)l3 Y
V N
I um[
PLENU!! CYLINDER LOCA TilRUST 2
/
FORCE 8
}
REACTOR g
UPPER GRID VESSEL 3
9 12 CORE SUPPORT
()<
STRUCTURE O
1 FLEXIDLE ELEf1ENT
()g
(,%
10 LONER GRID l
R) 1 FOUNDATION SPRING q
/////////
EARTH']UAXE INPUT
FIGURE 2 REACTOR VESSEL SCHEllATIC DRA'IlllG 12 t
(j)i 7 COI1 TROL R0D DRIVE SUPPORT f
y DRIVE STRUCTURE 11 O Ch6 i
10 (:)
0 15
,34 3 (;)
33 i
3
, UPPER llEAD T's'
?
s
\\
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z PLEt!Ul1 CYLillDER 2 k s
UPPER CORE N
/
GRID
\\
SUPPORT s
s
/
s STRUCTURE N
N,,,
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VESSEL f
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FUEL
\\
6C ASSEftBLY
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/
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s
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i
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7 o
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~
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LOHER
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3 O GRID y
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5
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1 yg g g \\\\ \\ \\ \\ \\ \\ \\\\ \\
L0HER HEAD SKIRT -s s
1
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