Integrated%20Multi-physics%20Simulation%20and%20Ceramic%20Breeder%20Blanket%20R

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Integrated Multi-physics Simulation and Ceramic
Breeder Blanket RD
Alice Ying UCLA With contributions from FNST
members
FNST Meeting August 18-20, 2009 UCLA
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Outline

• Status on Integrated Multi-physics Simulation
• For both Liquid and Ceramic Breeder Blankets
• Currently its development serves an Ad-Hoc Design
  Analysis Tool
• Ceramic Breeder Blanket RD
• Design Analysis (mainly for TBM)
• RD
• Mainly on the modeling development (small
  experiments planned aiming to provide data for
  code validation)
• Pebble bed thermo-mechanics
• Tritium permeation and purge gas conditions

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Integrated multi-physics Simulation Objectives

• Integrated multi-physics simulation is necessary
  to model real-world situations, explore design
  options, and guide RD
• A plasma chamber nuclear component in a fusion
  environment involves many technical disciplines
  and many computational codes such as
• MCNP for neutronics, CFD/thermofluid codes for
  FW surface temperatures, and ANSYS for
  stress/deformation, etc.
• Careful representation of a geometrically complex
  fusion component is essential to predict
  performance to a reasonable level of accuracy
• Because of the complex geometry of the fusion
  system, these analyses should be performed in 3D
  with a true geometric representation in order to
  achieve high quality prediction.
• An effective mechanism to integrate results of
  ongoing RD and continuously evolve to Validated
  Predictive Capability for DEMO
• Compiles data and knowledge base derived from
  many fusion RDs in out-of-pile facilities and
  fission reactors
• Provides high level of accuracy, reduces
  substantially risk and cost for the development
  of complex multi-dimensional system of the plasma
  chamber in-vessel components for DEMO and near
  term fusion devices

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Integrated multi-physics Simulation Basis

• A platform to streamline plasma chamber component
  design
• Utilizing a CAD-based solid component model as
  the common element across physical disciplines
• The multi-physical phenomena occurring in a
  fusion nuclear chamber system are modeled
  centering on CAD
• Many interfaces must be designed to facilitate
  information transfer, execution control, and
  post-processing visualization

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Utilizing a combination of fusion specific
research codes and off-the-shelf third party
software
Example MHD flows with heat transfer and natural
convection computed using codes developed in the
fusion community (such as HIMAG.) Traditional
CFD/thermal analysis for non-conducting flows
performed using off-the-shelf third party
software motivated by their speed and maturity
Sample analysis codes and mesh requirements in
ISPC

• DAG-MCNP (Sawans presentation)
• Assisted by CAD Translator such as MCAM

Physics Analysis code Mesh specification
Neutronics MCNP Particle in cell (PIC)
Neutronics Attila Unstructured tetrahedral mesh (node based)
Electro-magnetics OPERA (Cubit) Unstructured tetrahedral (Hex-) mesh (node based)
Electro-magnetics ANSYS Unstructured Hex/Tet mesh (node based and edge based formulations)
CFD/ Thermo-fluids SC/Tetra CFdesign Unstructured hybrid mesh (node based)
CFD/ Thermo-fluids Fluent (Gambit) Unstructured hybrid mesh (cell based)
MHD HIMAG Unstructured hybrid mesh (cell based)
Structural analysis ANSYS/ ABAQUS Unstructured second order Hex/Tet mesh (node based)
Species transport COMSOL or others Unstructured second order mesh (node based)
Safety RELAP5-3D MELOCR System representation code

• TMAP-4
• COMSOL Multi-physics Chemical modules
• Utilize analogy between mass and heat transport
  equations and extend CFD capability to solve mass
  transport equations with relevant BCs

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Initial DCLL MCNP Neutronics Analysis Assisted by
MCAM CAD Translator
Using MCNP parallel version with a shorter CPU
running time
Integrated into ITER FEAT 20 degree Model
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Initial DCLL MCNP Neutronics Results (MCAM
method)
Heating Rate (W/cc) and TBR
Mid-Plane
TBM Radial 1st Breeder layer
Neutron Heating
TBM Toroidal Mid-plane
Gamma Heating
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Visualization is an important element in the
integrated multi-physics predictive capability
simulation tool
DCLL He Circuit Design Analysis
He Temperature
He velocity above the outlet near the front
He velocity above the outlet near the back
He Velocity
Helium circuit flow characteristics
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Initial Results on the Assessment of FCI Thermal
Conductivity Requirement
Recall PbLi has higher temperatures than He
during DEMO operations
For FCI thermal conductivity 1 W/mk
TBM condition DEMO condition

He-inlet (Input) 350oC 350oC
He-outlet (Calculated) 400.6oC 413.1oC
DT (He) 50.6oC 63.1oC
PbLi-inlet (Input) 360oC 450oC
PbLi-Outlet (Calculated) 393oC 472.84oC
DT (PbLi) 33oC 22.84oC
Interpolated 1-D Heating profiles used in
analysis
Heat Generation W Removal (W) (ITER condition) Removal (W) (DEMO condition)
Be 312080.5
FS 132571
PbLi 342795 387230 272390
FCI 53527.5
Total 841974 850192 850180
He 462962 577790
Heat leak from FCI/PbLi to He 2.6 32
How will MHD velocity profile change this
requirement? (TBD)
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Temperatures at Mid-plane
He
FCI k 1 W/mK
PbLi
He
PbLi
DEMO
TBM
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Ceramic Breeder Blanket Design and RD

• Adopt edge-on approach
• Locate welds at the back (as much as possible)
• Reduce the amount of Be at the back
• Assemble the blanket from pre-fabricated breeder
  units

A completely assembled breeding unit to be
inserted into the structural box
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Predictive capability development for tritium
permeation estimation and purge gas flow design

• Accounting for flow, nuclear heating, and tritium
  production profiles
• - Velocity profile
• - Convection and conduction of heat
  (temperature profile)
• - Convection and diffusion of tritium
• - Isotopic swamping effect
• - Geometric complexity
• Approach Using COMSOL Multi-physics for fluid
  flow, temperature, convection and diffusion mass
  transport Mathematical Models
• Performed benchmark problems for code and problem
  set-up validation using literature data and TMAP4
• FEM method (not yet available for turbulent flow
  analysis)
• Extend a CFD/thermo-fluid code for mass transport
  analysis using user defined functions
• Eliminate data mapping from CFD code to COMSOL
• Accurate turbulent flow and heat transfer
  calculations

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Two Boundary Conditions Needed at the
Fluid/Structure Interfaces
Boundary Conditions
Initial COMSOL/SCTetra results compared with
existing data1

• Apply Sieverts law to calculate equilibrium
  concentration at the solid face (surface)
• Discontinuity in the concentration profile at the
  interface
• Continue diffusive flux at the normal direction
  of the interface

T2
T
1K. Kizu, A. Pisarev, T. Tanabe, Co-permeation of
deuterium and hydrogen through Pd, J. of Nuclear
Materials, 289(2001) 291-302
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Capability to predict packed bed thermo-mechanics
through-out its lifetime remains a key to the
success of ceramic breeder blanket designs
Much work remains to be done to establish such
capability

• Discrete element simulation of pebble bed
  provides contact forces at critical contact
  areas- eliminating potential design flaws

Example Pebble bed thermomechanics

• Issues
• 3-D Temperature profiles
• Differential thermal stress
• Contact forces at contact
• Plastic/creep deformation
• Particle breakage
• Gap formation

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Plot showing how forces propagate through pebble
contacts
orthorhombic packing obtained numerically
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Pebble bed Thermomechanics Progress and Plan

• FEM creep contact model for single pebble has
  been constructed simulated in an attempt to
  derive constitutive equations for use in DEM
  simulation (which otherwise cant be obtained)
• More analysis is needed to give better
  constitutive equation (compared with experimental
  pebble deformation data)
• Plan Conduct Creep Experiments on Pebble Bed
  (reconfirmation with Pebble Failure Map of
  correlation between single pebble failure and
  pebble bed loading pressure) estimation of
  Stress State due to differential thermal
  expansion between pebble bed and the structural
  wall

Average force at contact under various applied
loads (DEM simulation- UCLA)
Pebble mechanical integrity at high temperatures
under compressive loads (Li2TiO3) experiments
conducted at UCLA)
The forces exerted on the pebbles during the
operation should be less than 15 N or the
pressure applied to the pebble bed from
containing structural less than 5 MPa.