ucla - s.sharafat: iter tbm dec. ’04 dcll iter-tbm: design for accident relevant loading jaafar a....
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UCLA - S.Sharafat: ITER TBM Dec. ’04
DCLL ITER-TBM:Design for Accident Relevant
Loading
Jaafar A. El-Awady, P. Rainsberry,S. Sharafat, and N. Ghoniem,
University of California Los Angeles
ITER-TBM MeetingUCLA
March 2-5, 2005
UCLA - S.Sharafat: ITER TBM Dec. ’04
Outline
Model of Dual Coolant Lead Lithium (DCLL) Test Blanket Module.
“Back of the Envelope” FEM to determine design features, most relevant to accident loading.
Detailed FEM analysis Results.
Design Modifications based on FEM analysis.
UCLA - S.Sharafat: ITER TBM Dec. ’04
Dual Coolant PbLi Concept
1940ModuleHeight
38Top Plate
38Bottom Plate
First Wall
Mo Dagher,Mar.1st
UCLA - S.Sharafat: ITER TBM Dec. ’04
Accident Simulation
An accident scenario is simulated for a leakage of Helium into DCLL-TBM
Structural analysis was performed with the following conditions:
Leakage of 8 MPa Helium into DCLL-TBM, thus increasing the pressure in the breeder channels to 8 MPa
Extreme temperature conditions (T = 650oC) is applied as a uniform temperature on the entire DCLL-TBM
UCLA - S.Sharafat: ITER TBM Dec. ’04
Model for Back-of-the Envelope” FEM
8 MPa
Boundary ConditionsBack wall constrainedfrom moving in the horizontal Plane but free to expand in the vertical direction
Extreme Temperatures appliedT = 650oC
FEM
8 MPa
Back Wall
First Wall
Horizontal plane
Vertical direction
UCLA - S.Sharafat: ITER TBM Dec. ’04
“Back-of-the Envelope” Structure Analysis
UCLA - S.Sharafat: ITER TBM Dec. ’04
“Back-of-the Envelope” Structure Analysis
8 MPa
Alternating Pattern of high stresses
“shadowing” internal FW tube Structure:
Maximum Stress= 524.19 MPa
UCLA - S.Sharafat: ITER TBM Dec. ’04
Back-of-the-Envelope FEM Summary
FE Models must include Detailed Design of the FW and Supporting Ribs to identify critical design features.
“Back of the Envelope” FEM shows the weakest “link” to be the edges between the FW and the internal support structure.
Internal support structure – FW bonds will take the DCLL module beyond allowable stresses of 300 MPa at elevated temperatures.
UCLA - S.Sharafat: ITER TBM Dec. ’04
Detailed FEM Analysis
UCLA - S.Sharafat: ITER TBM Dec. ’04
Detailed FE-Model• A 3-D solid model of the TBM was created, including all of the FW channels.
• Over 200K elements.• Symmetry boundary conditions where applied to simulate the entire TBM
Meshed model showing internal support structures and FW-Channels
UCLA - S.Sharafat: ITER TBM Dec. ’04
Structure Analysis Results
Displacements:
Maximum Displacements occur at the tips and is equal to
8.435 mm
Back View
IsoFront View
UCLA - S.Sharafat: ITER TBM Dec. ’04
True Model Structure Analysis ResultsStress Distribution:
= 530 MPa
Critical section 1:(Rib-first wall)
View A
View A
UCLA - S.Sharafat: ITER TBM Dec. ’04
True Model Structure Analysis ResultsCritical section 2: (top plate – first wall connection)
View B
= 616 MPa
Looking from the inside up at the top PLATE
Top Plate
FW (from the inside)
Rib (not all the way totop Plate
UCLA - S.Sharafat: ITER TBM Dec. ’04
Channeled FW to Equivalent “Solid” FW
Stresses:
Equivalent Model with effective thickness for same stress
True Model
While the transformed model gave an average stress distribution equivalent to the true model, it wasn’tcapable of capturing the critical sections were the
stresses have doubled (these sections will be described in the following slides).
UCLA - S.Sharafat: ITER TBM Dec. ’04
Reinforced Rib-FW Structure
Adding more material between top Channel of FW and Top Plate (4 mm)
UCLA - S.Sharafat: ITER TBM Dec. ’04
Reinforced Rib-FW Contact Model: Structure Analysis
Max: ~415 MPa
Max: ~8 mm
Front view
Back view
UCLA - S.Sharafat: ITER TBM Dec. ’04
Reinforced Rib-FW StructureAdding material (4x4 mm)
Reduced Maximum Stresses from
530 MPa to 450 MPa
= 450 MPa
First Wall
Added material
UCLA - S.Sharafat: ITER TBM Dec. ’04
Reinforced Top Plate Side Wall Contact
= 415 MPa
Adding material (4x15 mm) Reduced Maximum
Stresses from 616 MPa to 415 MPa
UCLA - S.Sharafat: ITER TBM Dec. ’04
Summary
The entire DCLL TBM including FW channel detail was modelled for an over pressurization analysis (8 MPa).
Stress distribution on support structure/FW contact areas shows “shadowing” of FW channel detail on stress states.
Without reinforced support structure FW and Top/Bottom Plate contact areas, stresses are high.
Modifying internal Rib-FW/Top/Bottom-Plate contact areas can reduce maximum stresses significantly.
Details of the most optimized reinforcement design are yet to be determined.