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Page 1: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D

Alice YingUCLA

With contributions from FNST members

FNST MeetingAugust 18-20, 2009

UCLA

Page 2: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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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 R&D

– Design Analysis (mainly for TBM)– R&D

• 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

Page 3: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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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 R&DA 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 accuracyBecause 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 R&D and continuously evolve to Validated Predictive Capability for DEMOCompiles data and knowledge base derived from many fusion R&Ds in out-of-pile facilities and fission reactorsProvides 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

Page 4: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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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

Validation/Verification

CAD- Geometry

Mesh services Adaptive mesh/mesh refinement

Visualization

Neutronics Radiation damage rates

Thermo-fluid

Structure/thermo-mechanics

Species (e.g. T2) transport

Electro-magnetics

Data Management: Interpolation Neutral format

MHD

Coupled effect

Special module

Database/Constitutive equations

RadioactivityTransmutation

Time step control for transient analysis

PartitioningParallelism

Safety

Page 5: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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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 maturitySample analysis codes and mesh requirements in ISPC

Physics Analysis code Mesh specification

Neutronics MCNP Particle in cell (PIC)

Attila Unstructured tetrahedral mesh (node based)

Electro-magnetics

OPERA(Cubit)

Unstructured tetrahedral (Hex-) mesh (node based)

ANSYS Unstructured Hex/Tet mesh (node based and edge based formulations)

CFD/ Thermo-fluids

SC/Tetra & CFdesign

Unstructured hybrid mesh (node based)

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 RELAP5-3DMELOCR

System representation code

• DAG-MCNP (Sawan’s presentation)

• Assisted by CAD Translator such as MCAM

• 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

Page 6: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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Initial DCLL MCNP Neutronics Analysis Assisted by MCAM CAD Translator

Integrated into ITER FEAT 20 degree Model

CAD model Split CAD model and fill voids

MCNP model

Using MCNP parallel version with a shorter CPU running time

Page 7: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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Initial DCLL MCNP Neutronics Results (MCAM method)

Heating Rate (W/cc) and TBR

Neutron Heating

Gamma Heating

Mid-Plane

Neutron Heating Gamma Heating

Neutron Heating Gamma Heating

TBM Radial 1st Breeder layer

TBM Toroidal Mid-plane

Page 8: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

He inlet

He outlet

He Temperature

He Velocity

Helium circuit flow characteristics

Visualization is an important element in the integrated multi-physics predictive capability simulation tool

He velocity above the outlet near the front

He velocity above the outlet near the back

DCLL He Circuit Design Analysis

Page 9: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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Initial Results on the Assessment of FCI Thermal Conductivity Requirement

TBM condition DEMO condition

He-inlet (Input) 350oC 350oC

He-outlet (Calculated) 400.6oC 413.1oC

T (He) 50.6oC 63.1oC

PbLi-inlet (Input) 360oC 450oC

PbLi-Outlet (Calculated) 393oC 472.84oC

T (PbLi) 33oC 22.84oC

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%

For FCI thermal conductivity = 1 W/mk

How will MHD velocity profile change this requirement? (TBD)

Recall PbLi has higher temperatures than He during DEMO operations

0

5

10

15

20

0 5 10 15 20 25 30 35 40

FSLiPbSiC

Pow

er D

ensi

ty (

W/c

m3 )

Radial Distance from FW (cm)

Radial Distribution of Power Density in DCLL TBM Components

Neutron Wall Loading 0.78 MW/m2

LL

SiC FS

Interpolated 1-D Heating profiles used in analysis

Page 10: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

10TBM

DEMO

FCI k = 1 W/mK

Temperatures at Mid-plane He

He

PbLi

PbLi

Page 11: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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Ceramic Breeder Blanket Design and R&D

RAFS FW with He coolant channels

He purge gas pipe

Be pebbles

Ceramic breeder pebbles

Cooling plate

HCCB TBM module (710 389 510 mm)

He coolant manifolds for FW/Breeding zones

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

Purge gas inlet

Purge gas outlet

A completely assembled breeding unit to be inserted into the structural box

Page 12: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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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

Page 13: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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Two Boundary Conditions Needed at the Fluid/Structure Interfaces

GAP elementGAP element

Boundary 2_1Boundary 2_1 Boundary 1_2Boundary 1_2

C2C2

Face iFace iFace jFace j

Prism elementPrism element

C1C1

Fluid Solid

1K. Kizu, A. Pisarev, T. Tanabe, Co-permeation of deuterium and hydrogen through Pd, J. of Nuclear Materials, 289(2001) 291-302

1E-4 1E-3 0.01 0.1 1 101E-8

1E-7

1E-6

1E-5

1E-4

1E-3

J(D

2)/m

ol m

-2 s

-1

P(D2) (Pa)

Calculated 825K Measured 825K Sctetra Calculated 865K Measured 865K

1E-3 0.01 0.1 11E-8

1E-7

1E-6

1E-5

1E-4

1E-3

Sur

face

flux

/ m

ol m

-2 s

-1

Effective deuterium pressure (Pa)

Calculated H2 flux

Calculated D2 flux

Calculated HD flux Measured H

2 flux

Measured D2 flux

Measured HD flux

Initial COMSOL/SCTetra results compared with existing data1

T2T

1. Apply Sieverts’ law to calculate equilibrium concentration at the solid face (surface)

Discontinuity in the concentration profile at the interface

2. Continue diffusive flux at the normal direction of the interface

Boundary Conditions

Page 14: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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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

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

Much work remains to be done to establish such capability

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

breeder

Be pebbles

FW panel

with He channels

Internal cooling plate

Elastic/Plastic deformation region

T < 600 oC

High creep (thermal and irradiation) deformation region

Plot showing how forces propagate through pebble contacts

orthorhombic packing obtained numerically

Example: Pebble bed thermomechanics

Page 15: 1 Integrated Multi-physics Simulation and Ceramic Breeder Blanket R&D Alice Ying UCLA With contributions from FNST members FNST Meeting August 18-20, 2009.

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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 can’t 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

Loading pressure (MPa)Ave

rag

eco

nta

ctfo

rce

s(N

)

0 2 4 6 8 100

10

20

30

DEM results

y = 3.413 x

Pebble mechanical integrity at high temperatures under compressive loads (Li2TiO3) –experiments conducted at UCLA)

Average force at contact under various applied loads (DEM simulation- 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.


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