Depth-profiling and thermal desorption of hydrogen isotopes for plasma facing carbon tiles in JT-60U (Long term hydrogen retention) T. Tanabe, Kyushu University ☆Depth profiles in redeposited layers a nd eroded area Depth profiles of T in divertor tiles of JE T and JT-60U Depth profiles and TDS of hydrogen isotope s (H, D and T) ☆Deep penetration into the bulk Penetration thorough open pores of CFC and graphite Thermal diffusion Absorption at and/or permeation to the backside of tiles. 9th ITPA meeting on SOL/dive rtor physics, Garching, May 7-10, 2007
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Depth-profiling and thermal desorption of hydrogen isotopes for plasma facing carbon tiles in JT-60U (Long term hydrogen retention) T. Tanabe, Kyushu University.
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Depth-profiling and thermal desorption of hydrogen isotopes for plasma facing carbon tiles in JT-60U
(Long term hydrogen retention)
T. Tanabe, Kyushu University
☆Depth profiles in redeposited layers and eroded area Depth profiles of T in divertor tiles of JET and JT-60U Depth profiles and TDS of hydrogen isotopes (H, D and T) Importance of Isotopic exchange and tile temperature
☆Deep penetration into the bulk
Penetration thorough open pores of CFC and graphite Thermal diffusion Absorption at and/or permeation to the backside of tiles.
9th ITPA meeting on SOL/divertor physics, Garching, May 7-10, 2007
GasGraphite(Solid)Liquid
Determined by
○ : IR
● : NMR
▲ :EELS
A:C-H film ever produced
Hydrogen solubility
(very small)
T. Tanabe et al., Journal of Nuclear Materials 313–316 (2003) 478–490
RT
Hydrogen solubility
Hydrocarbons are unstable above 800K
Kee
pin
g n
earl
y th
e sa
me
leve
l
Above ~800K
Isotope exchange becomes easier
H2 and H0
Hydrogen retention and depth profile under H+ and H2 exposure
All grains are under the same static pressure
Below ~700K
No diffusion into bulk or particles
0
100
200
300P
SL
in
ten
sity [P
SL
/m
m2 ]
10
100
1000
104
105
106
0 5 10 15 20 25 30 35 40
Cyl_3Cyl_4Cyl4_BN4Cyl_7Cyl_8Cyl_9
Trit
ium
p
er d
isk
[k
Bq
]
Depth [mm]
BN4
BN7
Tritium activity is mostly on the plasma facing surface
JET tile : Cross section of cored hole in divertor base tile :BN4
Surface
Probably due to temperature difference
Backs side of BN7
Stripes corresponding the woven structure of 2-D CFC
PSL intensity [PSL/mm2]
020406080100
120
Absroption of low energy (gaseous) tritium
Cf. No stripes were observed on the front surfaceT. Tanabe et al., Journal of Nuclear Materials 313–316 (2003) 478–490
0
10
20
30
40
50
010203040
50PSL intensity [PSL/mm2]
50
40
30
20
10
0
PS
L in
tens
ity
[PS
L/m
m2 ]
inside
Outside
Tritium depth profile : observed by cross-sectional view of dome top tile in JT-60U divertor
SIMSH retention within <2.1m
~ 4.3 x 1016(/cm2)H/C at surface ~3.5 %
0
1
2
0 0.5 1 1.5 2 2.5Depth (m)
D/C
(%)
NRA_DM2_D/C(%)
0
1
2
3
4
5
0 0.5 1 1.5 2 2.5Depth (m)
H/C
(%)
Estimated H/C(%)
0
1
2
3
4
5
0 0.5 1 1.5 2 2.5Depth (m)
(H+D
)/C
(%)
Estimated (H+D)/C(%)
0
0
( H+D)/12C
H/12C
D/12C
Thin deposits on outer dome wing
NRA:D retention within 2.1m
~ 8.0 x 1016(/cm2) D/C ~ 2%(max)
Y. Oya, Y. Hirohata, et al., J. Nucl. Mater. 313-316 (2003) 209