Local Thermal Mechanical Analysis of Shield Blanket Module

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Local Thermal Mechanical Analysis of Shield
Blanket Module
Presented by Zhang Fu March 24 2003 Division
105 Southwestern Institute of Physics P. O. Box
432 Chengdu Sichuan 610041 China zhangf_at_swip.ac.cn
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1. Background
AGREEMENT signed by ITER IT and China PT G 16 TD
103 FP Design and analysis for blanket
modules in the neutral beam port
region (ITA 16-09) Start date Aug. 2003, Finish
date May 2004 Task Description (1) Design of
blanket modules Detailed design of a standard
module in the NB port region and conceptual
design of special blanket modules in the NB
port region are to be performed
incorporating proposed improvements in the
structure and layout of the shield block and
first wall. The coolant channel arrangement
in the shield block is to be consistent
with the design requirements. Drawings to show
the overall structure and partial details are to
be provided. The fabrication method of the
proposed blanket module design is to be
prepared. (2) Thermal/mechanical analyses of
the blanket structure Develop 3D models of the
shield block and first wall. Perform
3D thermal/mechanical analyses to evaluate the
thermo-mechanical integrity under surface/volumetr
ic heating and EM loads, and finally to
demonstrate the feasibility. The stress
evaluation is to be carried out according to the
design codes.
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2. Introduction
Shielding Blanket Function Provide the main
thermal and nuclear shielding to the vessel and
external machine components. Structure modular
configuration with seperatable First Wall
pannels. mechanical support,
cooling interface, electrical interface, assembly
maintenance access, and etc. Materials First
Wall -- Be, Cu, and SS multilayer Shield Block
-- SS Loadings Magnetic force, Plasma heating,
Neutron heating and Neutral Ion Beam heating,
Coolant pressure Loading conditions Normal
operation, VDE, Disruption Design Criteria ITER
structural design criteria for in-vessel
components

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• Criteria applied in this study
• M type damage
• Immediate plastic collapse and plastic instability

and

• Immediate plastic flow localization Not limited
  lt 7dpa
• Local fracture due to exhaustion of ductility ---
  not limited lt7dpa

• C type damage
• 3Sm rule

• Time independent fatigue

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Preliminary Design Results of NBI Module 11 ----
presented at Naka design meeting Based on the
standard module no. 4 provided by ITER IT
Mechanical support
Coaxial hydraulic connector
FW leg connection
Branch pipe
Shield Block
Electrical connector
First Wall
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Shield block after cooling holes drilled
Toroidal holes
Poloidal holes
Radial holes
Recess for manifold
island
Penetration holes for first wall leg did not
affect the interfaces Cooling holes will be
drilled before interface recesses
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Water flowing
Front manifolds
outlet
inlet
Flow guider inside cooling channel First
wall/shield block connection Same as No. 4
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Equal segmented First wall
Finger width How many fingers should be splitted?
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Hole density?
Should Cooling water be introduced?
Thickness?
Stress distribution?
Stress concentration?
Island ok?
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3. Thermal mechanical analysis ---- static
elastic analysis by ANSYS

• FEM Elements
• FW
• 8-nodes Brick elements
• Solid 70 for thermal and Solid 45 for stress
  analysis
• SB
• 10-nodes Tetrahedral elements
• Solid 87 for thermal and Solid 92 for stress
  analysis

• Materials
• Temperature dependent properties of Be, Cu and SS
  were adopted from ITER material handbook.

• Boundary conditions
• Thermal isolation on free surface was assumed
• Displacement and constraints were indicated the
  the specified FEM

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Loadings

• Neutron loads1
• In Be layer constant value 4.79 MW.m-3
• From the interface of Be/Cu
• 11.3143exp(-0.0988r)-4.0334exp(-0.199r)

Heat Flux on surface1 0.5MW.m-2  no neutral
beam heating was considered Heat Transfer
Coefficient 23.5 kW.m-2.K-1 in FW cooling
channels2 3366 W.m-2.K-1 in SB front
manifold 8050 W.m-2.K-1 in SB radial
holes Temperature of cooling water
373K Reference Temperature for thermal stress
293K
1 Design Descriptions Document, Section 1.2, G
16 DDD XX 01-06-07 W 0.1
2 Design Descriptions Document, Section 2.3, G
16 DDD XX 01-06-07 W 0.1
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FW Finger configuration drawing 16 0460 0005
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A
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M type criteria and 3Sm rule were confirmed. No
significant elastic follow up Thermal stress ?
secondary stress
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Length 500 mm Magnetic force 0.8121.624Z
MPa Coolant Pressure 3 MPa Max von Mise stress
intensity 46 MPa Deflection 0.2 mm
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Fatigue evaluation of point A --max peak stress
?Peff effective range of primary stress, not
considered in the calculation K?, K? -- amplitude
factors, related to elastic follow up and
Poisons effect respectively ?? -- equivalent
strain range ?6 Fingers with width of 60mm
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(A)
Symmetric plane
Another xz and zy surfaces Rigid plane without
rotatary around y axis
zy Free surface
E
Pressure only
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• t 20 mm d 80 mm
• The island should be cooled

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t
A
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Chamfers introduced at the front edge
t20 mm max Mise 516 MPa V1.5 Half
chamfered 490 MPa
1.2 Splitted without chamfer 483 MPa
1.1 Splitted chamfered 437 MPa
0.6 Chamfer length 5 mm
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Hole depth?
A
Displacement at point A and bending direction
B
b
?Better to introduce water deeper
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4. Discussions and summary

• Membrane stress lt Sm and Linear stress lt3Sm were
  confirmed in all cases. No significant elastic
  follow up effect was predicted. So, It is
  reasonable to consider thermal stress as
  secondary stress.
• Thermal stress in SB is very sensitive to the
  wall thickness, due to the poor thermal
  conductivity of SS. Stress concentration at the
  edge of penetration holes caused very high peak
  stress, which greatly affected the fatigue life.
  Chamfers at the front edges were available to
  diminish the thermal stress, although it
  increased the complexity near the split hole.
• In fatigue evaluation, Neubers rule was applied
  to convert stress to equivalent strain. This
  method may be over conservative, for thermal
  stress could diminish with small deformation.
  Elasto-plastic analysis should be carried out to
  check the necessity of the additional split.
• Symmetric and repeating boundary conditions were
  applied in the FEM models, but it cannot fully
  represent the whole module. At least, a 1/8 model
  including FW/SB connection is required.
• A powerful computer is still needed for both
  plastic analysis and large FEM model calculation.

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Please Give Your Comments and Suggestions.
Thank You