PbLi/T database:
status of the knowledge
I. Ricapito, ENEA CR Brasimone, FPN-FISING
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
OUTLINE
- Solubility and Sieverts’ constant in PbLi
- Bulk diffusivity in PbLi
- Mass transfer PbLi-gas
- He in PbLi
- Possible developments
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Solubility and Sieverts’constant
The knowledge of the function linking the tritium concentration
solubilized
in
LLE
with
the
corresponding
tritium
partial
pressure at equilibrium, CT=f(PT), is of basic importance for the
LLE breeder blanket concept because of the strong impact on:
 tritium permeation rate from the blanket into HCS;
 requested capacity of the Coolant Purification System for a
given value of allowed T partial pressure in HCS
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Solubility and Sieverts’constant
Impact of Sieverts’ constant on the tritium permeation rate for
PPCS-HCLL
700
T permeation rate into HCS (g/d)
650
REITER
SOLE
ηTES= 80%
-2
PHT, max= 1.5x10 Pa
LM flow-rate= 615 kg/s
600
550
500
450
400
350
PRF=1
300
250
200
150
100
PRF=10
50
0
1,0E-03
6,0E-03
1,1E-02
1,6E-02
2,1E-02
2,6E-02
3,1E-02
3,6E-02
4,1E-02
4,6E-02
Sieverts's constant (mol m-3 Pa-0,5)
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Solubility and Sieverts’constant
Sieverts’ law validity range /1
No deviation from Sieverst’s
law (Reiter)
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
Deviation from Sieverts’ law (Wu)
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Solubility and Sieverts’constant
Sieverts’ law validity range /2
From Polcaro
(1983)
Absorbed hydrogen weight (sample weight = 172 mg) as a function of time of absorption
(in min.) is shown at various hydrogen pressures: 1. PH2=20.87 kPa. 2. PH2=30.80 kPa.
3. PH2=47.01 kPa. 4. PH2=53.30 kPa. 5. PH2=77.41 kPa.
6. PH2=86.63 kPa.
7.
PH2=100.11 kPa.
One can see that the 5 fold increase in pressure (from plot 1 to 7) gives rise to about 7
fold increase of solubility (reviewed by A. Pisarev).
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Solubility and Sieverts’constant
Different values of Sieverts’ constant from different
authors (and different techniques)
S, at.fr. Pa
-1/2
Absorption
technique
10
-5
10
-6
10
-7
10
-8
10
-9
10
Aiello
Pierini et al
Katsuta et al
Wu
Wu & Blair
Chan & Veleckis
Fauvet & Sannier
Reiter
Feuerstein et al
Desorption
technique
-10
0,4
0,6
0,8
1,0
1,2
1,4
1000/T, K
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
1,6
1,8
2,0
-1
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Solubility and Sieverts’constant
Sieverts’ constant: last results from SOLE campaign (2005),
absorption technique
T (°C)
-1
350
400
450
500
550
600
650
10
-3
-1/2
Ks (mol m Pa )
Literature data (absorption technique)
-2
10
This experiment
Linear fit of experimental data
_._._. Reiter data
-3
10
1,6
1,5
1,4
1,3
1,2
1,1
-1
1000/T (K )
K s  0,237  e

K s  1,310  e
12844
RT

mol m-3 Pa-0.5
1350
RT mol m-3 Pa-0.5
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
SOLE (A. Aiello)
(Reiter)
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Bulk Diffusivity
Typical H2 pressure rise P(t) after saturation of the sample from gas
phase and fast evacuation of the hydrogen atmosphere (desorption
technique)
From Reiter, 1991
Curve (a) is desorption from the sample, container and vacuum walls. Curve (b) is a control run
without the sample. Curve (c) is the difference giving desorption from the sample.
Parameters of the experiment: T=591K, P=1.01 ×105Pa, tL=72h, m=250 g
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Bulk Diffusivity
Diffusion coefficient of hydrogen isotopes in LLE vs temperature
Reiter, 1991
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Bulk Diffusivity
Comparison of the bulk diffusion coefficients obtained by Terai (1), Reiter (2),
Shibuya (3), Fauvet (4)
(1) D=2.5 10-7exp(-27000/RT) m2s-1
(2) D=4.03 10-8 exp(-19500/RT) m2s-1
(3) D=2.62 10-9 exp(-6630/RT) m2s-1
(4) D(450°C)= 1.5×10-9 m2s-1
Terai’s values are the highest, probably
because determined in high hydrogen
partial pressure, with reduced residual
surface effects
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Mass transfer PbLi-gas
Hydrogen transfer from LLE to gas phase: mechanisms
related coefficients /1
CT,l
liquid bulk
CT*
liquid boundary
layer
interface
PT2,i
gas boundary
layer
PT2
gas bulk
JT ,l  hl  (cT ,l  cT* )
JT , r  kr  cT*2  ka  PT 2,i
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Mass transfer PbLi-gas
Hydrogen transfer from LLE to gas phase: mechanisms
related coefficients /2
mass transfer in the metal boundary layer hl
adsorption coefficient Ka
k
recombination coefficient Kr, with k S   a
 kr
Results from A. Viola* (1991)
T,K
hl, m s-1
723
673
633
6.51 10-5
5.74 10-5
5.12 10-5



0.5
Kr, m4mol-1s-1
Ka, mol m-2Pa-1 s-1
2.14 10-4
2.04 10-4
3.45 10-4
2.31 10-10
2.17 10-10
3.61 10-10
*Results have been achieved assuming valid the D diffusivity and Sievert’s constant values as
measured by Reiter
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Mass transfer PbLi-gas
Effective mass transfer coefficient: simplified description of the
tritium desorption from LLE into a gas phase: J=KD(Cbulk - Cinterface)
TERAI’s experiments (1991) on Tritium release from Pb16Li and influence
of H2 partial pressure on it
PH= 1E3 Pa
KD[ms-1]=2.510-3 exp(-30.7kJmol-1/RT); T=600-1100K, PH2=1000 Pa
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
He in PbLi
Formation of He bubbles and tritium trapping could have an important
impact on the blanket operation
Henry’constant
(from L. Sedano)
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
Diffusivity
(from L.Sedano)
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007
Possible developments
 Uncertainty remains about the range of validity of the Sieverts’ law.
On the other hand, there isn’t consensus on the Sieverts’ constant
values. Taking into account the big impact of such issues on the LLE
based blanket, there is the urgent need to find reliable and agreed data.
A new task is presently open in EU for a further experimental activity.
Anyway, an international collaborations should be of outstanding
importance in this field.
 Reference Tritium diffusivity values in bulk LLE (Terai and Reiter) are
spread in less than one order of magnitude. A sensitivity analysis should
be done in order to evaluate the impact of the different diffusivity
values on the tritium permeation rate into HCS: need of modelling
implementation.
 Only few data on T/LLE-gas mass transfer coefficients are available. A
new set of data should be extracted from TRIEX experimental
campaigns, planned in the next two years. To do it, the implementation
and validation of mathematical models in this ambit appears as a
priority.
Fusione, Tecnologie e Presidio Nucleare
Sezione Ingegneria Sperimentale
IEA Workshop on PbLi-T
Idaho Falls, 11-12/06/2007