Iván Fernández
CIEMAT
2nd EU-US DCLL Workshop, University of California, Los Angeles, Nov. 14-15th, 2014
Permeation facility
Absorption-desorption facility
PCTPro-2000
Trapping facility
Experiments under irradiation
Characterization of coatings
Deuterium release on ceramics for solid breeder
Materials database
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
2/25
CIEMAT facilities installed in the University of the Basque Country to
determine:
Diffusivity.
Solubility.
Permeability.
Surface constants (dissociation and recombination).
Trapping.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
3/25
Permeation column
Permeation column
V1
T2
Layout
of the facility
Low pressure
region
T1
Stainless steel
flange
PG
P1
S
Gold O-ring
P2
Low pressure
region
T1
F
High pressure
region
PG
S
UHV2
QMS
High pressure
region
PC
PG
Turbomolecular
pump
•
HPT
Rotative pump
UHV3
UHV1
PG Penning gauge,
The permeation
flux under diffusive
F furnace,
PC pressure
controller,
regime for
each temperature
depends on:
H2, D2
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
HPT high pressure transductor,
QMS quadrupole mass spectrometer,
sample
thickness,
S sample,
T1, T2 thermocouples Ni/Cr-Ni,
• load
pressure and
P1, P2 capacitive manometers (Baratron),
UHV Ultra-High Vacuum pumping units,
• gas
permeability (f)
V1: calibrated volume
4/25
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
5/25
1/ 2
1/ 2
1/ 2

2 2

R  T eff  f  p h
f  ph  d
2f  p h
d
 1n
n π

p t  
A t 
A
A
exp  D

2
2

V eff 
d
6D
6D
n
d
n 1


Pressure increment due to permeation

t 

 
Steady-state permeation regime
Transitory permeation regime
30
J 
f
d
1/ 2
( p1
p (Pa)
Gas flux under steady-state regime (J)
due to Δp through a membrane with
thickness d  Richardson’s law:
 p2 )
1/ 2
20
10
Dependence of permeability, diffusivity
and solubility on T (Arrhenius eq.):
f T   f 0  e
 E
RT
D T   D 0  e
 Ed
RT
K s T   K S 0  e
 Es
RT
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
0
0
L
(Time-lag)
t (s)
6/25
F
T1
Quartz nose
T2
Crucible and sample
P1 P2
QMS
BAG
LV1
Gs2
V2
T3
V1
LV2
P4
G1
Air compressor
UHV1
BAG
F
QMS
T3
V2
Bayard-Alpert sensor
Furnace
Quadrupole mass spectrometer
Pt resistance thermometer
Volume of expansion
Turbomolecular
pump
Filter
UHV2
Primary rotatory
pump
H2 ,D2 supply
P1,2
G1
P4
LV1,2
Capacitive manometers (Baratron)
Electro-pneumatic gate valve
High pressure transducer
Manual valves
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
Turbomolecular
pump
Primary rotatory
pump
UHV
G2
T1,2
V1
Ultra high vacuum pumping unit
Manual gate valve
Thermocouples
Experimental chamber
7/25
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
8/25
p(t)
Absortion
Pumping
x
Desorption
H2
c0
pl
x=a
(H)
p
f
Tungsten
crucible
PbLi
x=0
c(x)
t
t
t
t
l
p
r
Absorption
p N (t )  p N ,L 
RT N
V
K s pL
1/2
8

V s  1  2
π


1
 (2 n  1)
2
e
2
2
2
 D ( 2 n  1 ) π t /( 4 a )
n0



Desorption
p N (t ) 
RT N
V
(K s p L
1/2
Vs )
8
π
2

1
 (2 n  1)
2

 1e
2
2
2
 D ( 2 n  1 ) π t /( 4 a )
 e
2
2
2
 D ( 2 n  1 ) π τ P /( 4 a )

 1e
2
2
2
 D ( 2 n  1 ) π τ /( 4 a )
L

n0
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
9/25
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
10/25
F4E-FPA-372 (R&D experimental activities in support of the conceptual design of the European
Test Blanket System).
Determination of H and D recombination and dissociation constants in Eurofer and SS-316L
(permeation facility).
Experiments on H and D absorption-desorption in Zr-Co getters.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
11/25
Fully automatic equipment with wide ranges of temperature, pressure and sample size.
Based on the Sieverts’ method: a sample at known pressure and volume is connected to
a reservoir of known volume and pressure through an isolation valve.
Opening the isolation valve allows new equilibrium to be established.
Gas sorption is determined by difference in actual measured pressure (Pf) versus
calculated pressure (Pc).
Temperature range
Calibrated reservoirs
Operating pressure
range
Pressure
measurements
Maximum sensitivity
-260ºC to 500ºC with a range of simple holders options
5 high pressure calibrated volumes
From vacuum to 200 bar
Pressure regulation: automated PID software controlled
Aliquot sizing ~Fixed P, Δp or f(Δp)
4 pressure transducers
Pressure regulation: 2 transducers for vacuum to 200 bar
Experiment pressure: 1 transducer for vacuum to 200 bar
3 μg H2 equivalent to 0.3 wt% for 1 mg of sample
(with the MicroDoser sample holder)
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
12/25
The facility has been calibrated using a sample of LaNi5: PCT
curves at different temperatures.
Manual
valve
PCTPro-2000
A new design of the reactor has been implemented and a
glove box has been manufactured (samples handling).
User
interface
Furnace
1200ºC
P=2 kW
Hydrogen
• Glass-quartz
• SS-304
• pMAX=2 bar
• pMAX=15 [kg/cm2]
Helium
A new design of the reactor has been
implemented and a glove box has been
manufactured (samples handling).
Technical problems for a long time, but the
facility is operational again.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
13/25
Thermal desorption spectrometry.
Helium implanting + D electrolytic
loading by applying cathode overpotentials  thermal desorption and
mass spectrometry analysis (He and
D).
Deuterium loading
Dissociation
2D2SO4
4D+ + 2SO4=
ANODE
(Pt wire)
1N D2SO4 in D2O
0.25 g/l NaAsO2
Anode reaction
2SO4=
2SO4 + 4e2SO4 + 2D2O
CATHODE
(sample)
2D2SO4 + O2
Cathode reaction
4D+ + 4e2D2
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
14/25
Deuterium evolution
(D-atoms/(g-alloy*sec))
 f 
 ln  2 
T 
E
 p 
 a
R
 1 



T 
 p
(Lee & Lee, 1986)
Type of trap
Binding energy
(eV)
Interstitial
0.03 - 0.10
Dislocations
0.25 - 0.31
Vacancies
0.40 - 0.50
Cluster
0.60 - 0.70
Inclusion
0.90 - 1.00
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
15/25
1.8 MeV Van de Graaff accelerator.
Beam: electrons, 0.25 to 1.8 MeV, 10 pA to 150 µA
Samples from ≈ 3 mm2 to about 20x20 cm2
For insulator work typical dpa rates range from about 10-12 to 10-8
dpa/s and ionization rates (Bremsstrahlung or direct electron
irradiation) from 0 to ~104 Gy/s
10-3 dpa/day for steels in volumes of approximately 3x3x1 mm3.
Radiation enhanced
permeation chamber
Radiation enhanced
desorption chamber
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
Irradiation chamber and
accelerator
16/25
BA activities: radiation enhanced D/He absorption and desorption in ceramics.
Radiation enhanced diffusion and redistribution of helium in LiNbO3.
Radiation enhanced deuterium absorption in different oxides (SiO, MACOR, Al2O3).
Radiation enhanced deuterium absorption in SiC.
ALUMINA
10
ALUMINA
-8
5 10
-9
Unirradiated
-9
During
irradiation
10
3 10
2 10
-9
-9
As a consequence of irradiation
the absorbed deuterium is
stabilized in deeper traps
increasing the temperature for
desorption
-9
Irradiated
2
D rele ase rate (m bar l/s)
10
Without
irradiation
2
D rele ase rate (m b ar l/s)
4 10
1 10
-9
-10
0
10 00
20 00
time (s)
30 00
40 00
50 00
0
10 0
15 0
20 0
25 0
Temperature (
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
30 0
o
35 0
40 0
45 0
C)
17/25
Deuterium absorption for RB-SiC is very low, but noticeable absorption occurs when both
material and deuterium gas are subjected to a radiation field increasing linearly with
irradiation dose.
5 10
-9
1,4 10
-8
1,2 10
-8
1 10
-8
8 10
-9
6 10
-9
4 10
-9
2 10
-9
4 10
3 10
-9
deuter ium r ele ase r ate (m bar l/s)
D eu ter iu m rele ase rate (m b ar l/s)
Silicon Carbide
30 h irradiation
-9
10 h irradiation
2 10
-9
40 h unirradiated
1 10
-9
70 keV D+
Implanted SiC
The main desorption T for
implanted D is higher than
800ºC
0
0
0
100
200
300
400
500
600
700
800
o
T( C)
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
0
10 0
20 0
30 0
40 0
50 0
60 0
70 0
80 0
o
T( C)
18/25
Thermal gradient is a driving force for tritium permeation across plates in diffusion-limited
regimes (Ludwig-Sôret or thermo-transport effect).
It has been considered as relevant for FW tritium balances correcting permeation by
factors of ~40% of the permeation flux.
Values of heat of thermo-transport are unavailable in literature. They are expected to be
negative (as in the case of alpha iron)  possible reduction of permeation across Eurofer
walls.
New basic transport data for H/D in Eurofer will be generated.
Expected isotopic differences can be compared and isotopic thermal-migration values
extrapolated for tritium.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
19/25
Test chamber divided into 2 smaller chambers: pressurized gas chamber and vacuum
chamber. Test sample (membrane) located between the gas cell containing H2 or D2 at a
controlled pressure and the coupling to the gas detector.
Annealed cooper rings.
Thermal gradient between the sample surfaces achieved by an oven in thermal contact
with one face and water cooling on the other face.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
20/25
Measurements in SS 316L and Eurofer.
T range: 300-550ºC; H2/D2 partial pressure range: 0.1-1000 Pa.
Diffusion measurements: use of a Pfeiffer Smart Test commercial gas leak detector with
sensitivities of ≥10−8, 10−10, and 10−12 mbar l/s for the three mass selection possibilities: 2
(2D or 1H2), 3 (3He or 1H2D), or 4 (4He or 2D2) respectively and a detection limit of
~1·10−12.
The experimental system can be used as an independent unit that may be set up in
different locations or can be integrated in the beam line of the CIEMAT Van de Graaff
electron accelerator, allowing thermo-diffusion measurements to be performed under
irradiation conditions if considered pertinent.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
21/25
Eurofusion WP5.3.1, WP5.3.2.
Al2O3 coatings produced by Pulsed Laser Deposition and ECX.
Schedule 2014-2015:
Permeation chamber modification to perform initial measurements during irradiation at temperatures up to 250
C by the end of 2014.
A new permeation chamber to increase sample temperature will be fabricated in parallel (during 2015).
Perform permeation experiments under irradiation.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
22/25
2 MeV Electron Van de Graaff accelerator
60 keV DANFYSIK ion implanter
SIMS
Optical/Confocal
microscopy
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
Dual Beam Microscopy
(FIB/SEM)
23/25
Study of the D depth distribution and thermal release in three different candidates as
solid breeder: Li4SiO4, Li2TiO3 and a third one with a higher Li:Si proportion (3:1).
RNRA technique.
Relevant correlations with the ceramic microstructural and morphological features
(porosity, pore size distribution and grain size) have been found.
Annealing at T=100ºC promotes D release;
for T≥150ºC the whole D is released.
D atomic concentration is significantly higher
at the surface than in the bulk  surface play
an important role in the D release.
Comparison of D release data for samples
with high porosity & low grain boundary
density and samples with low porosity & high
grain boundary density  grain boundary
might be an alternative path to pores for D
diffusion.
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
24/25
The creation of a wide materials database for fusion technology was suggested several
years ago (e.g. Lead–lithium eutectic material database for nuclear fusion technology, E.
Mas de les Valls et al., Journal of Nuclear Materials 376 (2008) 353–357).
Following this idea, a shared and agreed materials database for tritium transport
modeling as a computer expert system should be promoted.
Needed for future qualification and licensing of components and systems.
Chemical interactions data should be included.
Possible proposal for the next IEA meeting?
I. Fernández – “Experimental data for tritium transport modeling”
2nd EU-US DCLL Workshop. 14-15 Nov 2014. Los Angeles (CA), USA.
25/25
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