There are several heat and mass diffusion  problems which affect to the IFC chamber design.  New simulation models and experiments are  needed to take into account the extreme conditions  due to ignition pulses and neutron flu

Alvarez Ruiz, Jesus

Garoz Gómez, David

Gonzalez Arrabal, Raquel

Hontoria, R.S.

Perlado Martín, José Manuel

Rivera de Mena, Antonio

Servicio de Coordinación de Bibliotecas de la Universidad Politécnica de Madrid

DSL2011      28 June 2011 Vilamoura, Portugal 1 / 20
Diffusion Issues of Heat and Light 
Species in Laser Fusion Devices
D. Garoz, R.S. Hontoria, J. Álvarez, A. Rivera,
R. González-Arrabal, J.M. Perlado
Institute of Nuclear Fusion (DENIM)
DSL2011      28 June 2011 Vilamoura, Portugal
DSL2011      28 June 2011 Vilamoura, Portugal 2 / 20
Index
• Brief introduction to Nuclear Fusion
– Magnetic confinement and Laser driven nuclear fusion
– Current status
• Inertial fusion confinements IFC
– Direct ignition scheme
– Energy distribution of fusion products
– Energy deposition onto the wall chamber
– IFC chamber description
• Heat and mass diffusion problems
– Issues in first wall
– Issues in lens
– Issues in structural and coolant
– Issues in blanket (liquid, solid)
– Another issues: vacuum chamber, thermodynamical cycle...
• Conclusions
DSL2011      28 June 2011 Vilamoura, Portugal 3 / 20
Brief introduction to Nuclear Fusion
Nuclear Fusion
Extremal conditions
•High temperature
•High confinement
Inertial confinement Magnetic confinement
Laser drive Tokamak, stellarators
NIF chamber
Livermore, USA
JET tokamak
Oxfordshire, UK
DSL2011      28 June 2011 Vilamoura, Portugal 4 / 20
Nuclear fusion: Current status
Demonstrator
GAIN > 1
Commercial
Reactor
Inertial confinement Magnetic confinement
Demonstration 
of fusion ignition 
by the end 2012
Under construction in Cadarache, 
France. Programmed ignition in 2026.
ITER 
design
NIF chamber
Livermore, USA
LIFT
DEMO
DEMOnstration power 
plant 2-4 GW
DSL2011      28 June 2011 Vilamoura, Portugal 5 / 20
HiPER project
October 2006
DSL2011      28 June 2011 Vilamoura, Portugal 6 / 20
HiPER tasks
Materials R&D
Heat and mass 
diffusion simulations
Facility design 
and costing
Chamber design
Blankets
Fusion target design 
Systems integration
High density matter, direct 
drive, fast and shock ignition, 
target manufacturing
Safety, Environmental analysis 
and fusion Technology.
DSL2011      28 June 2011 Vilamoura, Portugal 7 / 20
Inertial Fusion Confinement IFC
HiPER fast ignition scheme
DSL2011      28 June 2011 Vilamoura, Portugal 8 / 20
Energy distribution of fusion products
Species Energy (J) %
X-rays 6.5x105 1.42
Neutrons 3.6x107 75.03
Deuterons 2.9x106 6.04
Tritons 3.5x106 7.29
He 3.6x106 7.5
C 1x106 2.08
Gamma rays, 
H, 3He, 13C 3x10
5 0.63
Perkins spectra 100 ps simulation
Distribution of 48 MJ 
shock ignition target
DSL2011      28 June 2011 Vilamoura, Portugal 9 / 20
Energy deposition
X-rays and ions (deuterons D, tritons T and Helium He are deposited in the 
first microns of the chamber wall. Temporal and spatial deposition have been 
calculated for a tungsten armor at 5 meters (Alvarez 2011).
Neutrons (75 % of the energy) show almost no interaction 
with the metallic wall. Mostly stopped in the blanket.
Time (s)
DSL2011      28 June 2011 Vilamoura, Portugal 10 / 20
IFC chamber design
Armor
Structural
material
Coolant
Breeder
Blanket
Thermal Cycle
Electricity or H2 
production
Tritium 
production
Fusion fuel
DSL2011      28 June 2011 Vilamoura, Portugal 11 / 20
Heat and mass diffusion problems
• Diffusion into metals (armor or structural material)
– Pure metals or alloys
– ODS and nano-structured materials
– Metals with atomistic defects (vacancies, interstitial, bubbles...)
• Diffusion in liquids or gas.
– Liquid metal breeder blanket (Li or LiPb)
– Coolant (He)
– Vacuum chamber and pumps
• Diffusion between two media
– Armor and structural with or with out interlayer
– Vacuum chamber and armor
– Structural and coolant (He)
– Structural and blanket (Li or LiPb) with interlayer (SiC or W)
DSL2011      28 June 2011 Vilamoura, Portugal 12 / 20
Issues in first wall: temperature
Energy 
deposition
Finite element solver ASTER CODE is used to estimate thermo-mechanical 
behavior in the first wall (temperature, stress, deformation)
Bunch of 5 shock ignitions 
48 MJ in 10 seconds 
(scenario HiPER 4a) 
First wall melting avoided
DSL2011      28 June 2011 Vilamoura, Portugal 13 / 20
Local increase of temperature material expansion
Tangential compression-traction stresses due to geometrical restrictions.
Issues in first wall: stress and strain
W plastically deforms depth < 20 m, 
suffering compression-traction cycles.
Temporal evolution of tangential stress 
and longitudinal deformation in the first 
wall W (1mm)- SS316 (1cm).
DSL2011      28 June 2011 Vilamoura, Portugal 14 / 20
Issues in the first wall: light species
TMAP7 software is used to estimates diffusion 
of light species implanted in first wall.
Bulk diffusion and surface reactions, 
control the amount of tritium returned 
to chamber in HiPER 4a conditions. 
Figures for tritium diffusion in first wall, 
W (1mm) – SS316 (1cm).
For reactor design, it is needed to 
implement other implanted species 
and tramps (vacancies and He 
bubbles) in the model.
DSL2011      28 June 2011 Vilamoura, Portugal 15 / 20
Issues in lens
Silica lenses are located at 8 meters from the center of the chamber
Deflection of ions is mandatory 
to avoid melting. X-rays can be 
supported, only located stress.
Irradiation Irradiation Shadow
-0.16           0           0.31 -0.25           0           0.25 MPa
Heat diffusion has been 
studied with 2D model.
DSL2011      28 June 2011 Vilamoura, Portugal 16 / 20
Issues in structural and coolant
Tritium can be mixed 
with coolant (He)
Mass diffusion 
restrictions due to 
geometry, materials 
and junctions
Close design with 
structural, coolant 
and blanket
Diffusion issues located in the area of the structural and coolant
Breeder blanket concept 
for ITER (Rampal 2005)
Atomistic defects in 
structural modify 
metal properties and 
aid tritium retention
Thermal gradients 
due to geometry and 
different materials
Formation of H2 and 
He in structural due 
to nuclear reactions.
DSL2011      28 June 2011 Vilamoura, Portugal 17 / 20
Issues in blanket
Tritium production
Diffusion restriction 
due to corrosion of 
the wall in contact 
with Li or LiPb
Heat and mass diffusion in 
a liquid breeder blanket 
with motion
Breeder blanket concept 
for ITER (KIT/IMF III)
Tritium diffusion 
and recuperation 
from the breeder 
(He bubbles)
Diffusion issues located in the area of the blanket
Estimation and 
localization of 
retained tritium
DSL2011      28 June 2011 Vilamoura, Portugal 18 / 20
Another issues
Vacuum chamber
•Vacuum pump
•Tritium recycling
Thermodynamical 
cycle
It is important to know potential common heat an mass 
diffusion issues in magnetic and inertial fusion reactors
NIF concept
HAPL vacuum pumps
DSL2011      28 June 2011 Vilamoura, Portugal 19 / 20
Conclusions
• There are several heat and mass diffusion 
problems which affect to the IFC chamber design.
• New simulation models and experiments are 
needed to take into account the extreme conditions 
due to ignition pulses and neutron flux.
DSL2011      28 June 2011 Vilamoura, Portugal 20 / 20
Diffusion Issues of Heat and Light
Species in Laser Fusion Devices
Thank you for your attention
DSL2011      28 June 2011 Vilamoura, Portugal 21 / 20
Issues in first wall: junction interface
Because of the different expansion coefficients, W and structural, 
there is a discontinuity in the tangential stress (t)
t decreases by selecting structural material with:
lower expansion coefficient (F82H) and high thermal conductivity (Al5657).
DSL2011      28 June 2011 Vilamoura, Portugal 22 / 20
Issues in lens
Silica lenses located at 8 meters from the center of the chamber
Deflection of ions is 
mandatory to avoid 
melting. X-rays can 
be supported, only 
located stress.
Accumulation of 
atomistic defects 
increases the 
absorption. At high 
temperatures, 
annealing reduce 
defects.
Irradiation Irradiation Shadow
-0.16           0           0.31 -0.25           0           0.25 MPa


Diffusion Issues of Heat and Light Species in Laser Fusion Devices

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Diffusion Issues of Heat and Light Species in Laser Fusion Devices

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