Integrated Effects of Disruptions and Integrated Effects of Disruptions and ELMsELMs on Divertor and Nearby Componentson Divertor and Nearby Components

Valeryi SizyukAhmed Hassanein

School of Nuclear Engineering Center for Materials Under eXtreme Environment

Purdue University

PFC community meeting at UCLAAugust 4-6, 2010, Los Angeles CA

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Outline

HEIGHTS Integrated Package

Divertor Nearby Fluxes and Assumptions

Application to ITER Divertor Area

Simulation Results

HEIGHTS Upgrade and Current Status

Summary

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Recent Publications ELMs and Disruptions

1. V. Sizyuk and A. Hassanein, Damage to nearby divertor components of ITER- like devices during giant ELMs and disruptions, Nucl. Fusion (2010), Just submitted

2. A. Hassanein, T. Sizyuk, V. Sizyuk, G. Miloshevsky, Impact of various plasma instabilities on reliability and performance of tokamak fusion devices, Fusion Eng. Des., In Press, (2010)

3. S. El-Morshedy, A. Hassanein, Analysis, verification, and benchmarking of the transient thermal hydraulic ITERTHA code for the design of ITER divertor, Fusion Eng. Des., In Press, (2010)

4. A. Hassanein, T. Sizyuk, I. Konkashbaev, Integrated simulation of plasma surface interaction during edge localized modes and disruptions: Self-consistent approach, J. Nucl. Mater., 390-391 777 (2009)

HEIGHTS Integrated Package

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Recent Publications (Cont.) Vertical Displacement Events

1. A. Hassanein and T. Sizyuk, Comprehensive simulation of vertical plasma instability events and their serious damage to ITER plasma facing components, Nucl. Fusion, 48 115008 (2008)

2. A. Hassanein, T. Sizyuk, M. Ulrickson, Vertical displacement events: A serious concern in future ITER operation, Fusion Eng. Des., 83 1020 (2008)

3. S. El-Morshedy, A. Hassanein, Transient thermal hydraulic modeling and analysis of ITER divertor plate system, Fusion Eng. Des., 84 2158 (2009)

Runaway Electrons1. V. Sizyuk and A. Hassanein, Self-consistent analysis of the effect of runaway

electrons on plasma facing components in ITER, Nucl. Fusion, 49 095003 (2009)

HEIGHTS Integrated Package

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Capabilities of Integrated HEIGHTS AnalysisCapabilities of Integrated HEIGHTS Analysis

HEIGHTS Integrated Package

MHD RadiationTransport

Plasma/materialInteraction

ExternalCircuit

AtomicData

Electrode Thermal Conduction

& Hydraulics

Energy Deposition(Ions, Plasma, Laser, Electrons)

TargetThermal Conduction

& Hydraulics

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Physical Processes, an Integrated ApproachPhysical Processes, an Integrated Approach

Monte Carlo algorithm for SOL plasma impact:– Ions, electrons (initial and secondary), photons (secondary);– 3D Energy deposition into solid and plasma in magnetic field;– All scattering processes including Bremsstrahlung, Compton Absorption,

Photoabsorption, and Auger Relaxation

Thermal conduction:– Implicit scheme for heat conduction in plasma;– Explicit scheme for the heat conduction in liquid target;– Vaporization model for the solid target

MHD:– Total variation diminishing scheme in Lax-Friedrich formulation;– Magnetic field divergence correction;– Implicit scheme for magnetic diffusion

Radiation transport:– Weighted Monte Carlo algorithms;– More than 2500 spectral groups for divertor plasma;– Full 3D simulation

HEIGHTS Integrated Package

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HEIGHTS modeling of LOFA and comparison with experimental data*

*T.D. Marshall et al., Fusion Technology, 37 38 (2000)

W of 0.8-mm thick

W of 0.1-mm thick

Modeling of Runaway Electrons Energy Deposition and Structural Response

Major Results: VDE and Runaway Electrons

HEIGHTS Integrated Package

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Major Results: ELM and Disruptions

Tungsten Surface Temperature as a function Tungsten Surface Temperature as a function of ELM Intensity for 1 msof ELM Intensity for 1 ms--durationduration A. Hassanein, T. Sizyuk, I. Konkashbaev, J. Nucl. Mater., 390-391 777 (2009)

Depth of Tungsten Melting under Boron Layer B-W Combination (GA concept)C.P.C. Wong, "Innovative tokamak DEMO first wall and divertor material concepts", J. Nucl. Mater., 390-391 1026 (2009)

HEIGHTS Integrated Package

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Research ObjectiveResearch Objective

Divertor Nearby Fluxes and Assumptions

Radiation to divertor nearby surfaces during ELM and disruption Predicting heat loads in comparison to the strike-point

3D ITER Geometry

Integrated Model

Self-consistent Physical Processes

ITER ELM Parameters:

Predicted:"In a multi-device comparison it was found that the relative ELM size scales inversely with pedestal collisionality. Given the required high Tped , this scaling predicts an unacceptably large ELM size, ∆WELM /Wped > 15%, for ITER.“ *

* M.N.A. Beurskens et al., Plasm Phys. Control. Fusion, 51 124051 (2009)Desirable:"A maximum tolerable ELM energy loss limit of ∆WELM = 1 MJ, which corresponds to ∼1% of the pedestal stored energy ∆Wped has recently been set.“ **

** A. Zhitlukhin et al., J. Nucl. Mater., 363-365 301 (2007)

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ITER DivertorITER Divertor Coordinate Coordinate SystemSystem

HEIGHTS 3-D Coordinate SystemDesign taken from: J. Palmer et al., Recent developments towards ITER 2001 divertor maintenance, Fusion Eng. & Design, 75-79 583 (2005)

Application to ITER Divertor Area

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HEIGHTS Computational DomainHEIGHTS Computational Domain

Carbon

Application to ITER Divertor Area

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Plasma Impact @ ITER Divertor SurfaceT = 3.5 keVQped = 126 MJRdiv = 6.5 mB = 5.0 T

= 5.0 deg

Exponential distribution in SOL

Giant ELMQELM

10% Qped

DisruptionQD

Qped

t = 0.1 – 1.0 ms

Simulation Results

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Spatial Energy DepositionSpatial Energy Deposition

Simulation Results

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Divertor Erosion ProfilesDivertor Erosion Profiles

Simulation Results

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Divertor Plasma Density EvolutionDivertor Plasma Density Evolution1.0 ms giant ELM

Simulation Results

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Radiation Fluxes Radiation Fluxes Evolution Nearby Evolution Nearby Divertor PlateDivertor Plate

1.0 ms giant ELM

Simulation Results

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Divertor Heat Load and ErosionDivertor Heat Load and Erosion0.1 ms, 12.6 MJ

Simulation Results

Plasma Impact Dominance

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Divertor Heat Load and ErosionDivertor Heat Load and Erosion0.1 ms, 126 MJ

Simulation Results

Irradiation Dominance

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Radiation Energy Deposition during ELMRadiation Energy Deposition during ELM

Energy deposition at the strike point:

Wt = Wimp + Wrad182.8 = 143.3 + 39.5180.8 = 148.1 + 32.790.7 = 77.9 + 12.8

[J/cm2]

Simulation Results

Rad

iatio

n en

ergy

, J/c

m2

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Radiation Energy Deposition during DisruptionRadiation Energy Deposition during Disruption

Energy deposition at the strike point:

Wt = Wimp + Wrad248.9 = 161.1 + 87.860.8 = 6.5 + 54.3

[J/cm2]

Simulation Results

Rad

iatio

n en

ergy

, J/c

m2

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ITER Divertor Design UpgradeITER Divertor Design Upgrade

Design taken from:R.A. Pitts et al., Status and physics basis of the ITER divertor,

Phys. Scr., T138 014001 (2009)

HEIGHTS Upgrade and Current Status

?

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5 Layers Geometry AMR5 Layers Geometry AMR

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3

2

1

0

HEIGHTS Upgrade and Current Status

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Magnetic Field ReconstructionMagnetic Field Reconstruction

HEIGHTS Upgrade and Current Status

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Summary and ConclusionSummary and Conclusion

HEIGHTS models and simulation package are upgraded and applied to plasma evolution in divertor nearby areas during ITER giant ELM and disruptions

Heat loads and erosion of carbon vertical target were calculated for ITER-like geometry

Simulation confirmed that nearby divertor surfaces may have radiation fluxes comparable with values incident on the vertical target => Damage to nearby components

The simulation results prove necessity of future model and code enhancement to the new design and its optimization

More detail analysis will be available:V. Sizyuk and A. Hassanein, “Damage to nearby divertor components of ITER- like devices during giant ELMs and disruptions,” Nucl. Fusion (2010), Submitted.

Thank you very much for the attention