JAEA-Review-2010-065.pdf:15.99MB - 日本原子力研究開発機構

Hydrogen Generation in the System of
Water–Adsorbent Containing the Organic Extractant
by Gamma-Ray Radiation
Y. Koma, K. Matsumura, S. Watanabe, K. Nomura and Y. Sano
The extraction chromatography is a promising technique
for Am and Cm separation from a highly radioactive
solutions of spent fuel reprocessing and employs the
adsorbent composed of the porous silica particle, polymer
and an extractant 1) . In the system, water and the adsorbent
will generate hydrogen by gamma radiation. Generation of
hydrogen should be considered for explosion safety, thus,
was studied using several extractants.
Adsorbents containing CMPO (n-octyl(phenyl)-N,N-
diisobutylcarbamoylmethylphosphine oxide), TODGA
(N,N,N'N'-tetraoctyl-3-oxapentane-1,5-diamide), HDEHP
(bis(2-ethylhexyl)hydrogen phosphate), R-BTP (2,6-
bis(5,6-di-isohexyl-1,2,4-triazine-3-yl)pyridine) and TRPEN
(N,N,N’,N’-tetrakis((5-octyloxypyridin-2-yl)methyl)ethylen
ediamine), were irradiated with gamma-ray of Co-60 in
water at room temperature. The mixture of water and the
adsorbent was contained in a vial for static irradiation
whereas the stainless steel vessel for irradiation with Ar gas
bubbling. The dose rate was about 3 kGy/h. Gas was
sampled and analyzed by gas chromatography.
When CMPO adsorbent is immersed in water with the
ratio of mass of adsorbent and volume of water up to
0.36 g/cm 3 , G value is increased comparing the value for
water and this suggests a synergy effect in hydrogen
production. At the ratio of 0.50 g/cm 3 , G value is
suppressed about 40% of the value for water. It seems that
hydrogen generated is retained longer and/or consumed in
the system.
Figure 1 shows G values obtained for the
water–adsorbent system at the ratio of 0.01 g/cm 3 in the
G value
1-16
0.4
0.3
0.2
0.1
0
CMPO
/SiO -P
2
TODGA
/SiO -P
2
HDEHP
/SiO -P
2
R-BTP
/SiO -P
2
Adsorbents
Advanced Processing Unit, ANSRD, JAEA
TRPEN
/SiO -P
2
Fig. 1 G values for the water–adsorbent system at
0.01 g/cm 3 . The adsorbent–water mixture was
irradiated for 1 h at standing.
SiO 2 -P
JAEA-Review 2010-065
Water
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static irradiation. The G value is increased for the
two-phase system when compared with that of water, and
the extent is depends on the adsorbent. This implies that
addition of support particle denoted as ‘SiO 2-P’ as well as
extractant enhances radiolysis. Nitric acid helps to
suppress G value of H 2 for water 2) and this is also applied to
the system.
Stirring the system with Ar during irradiation increases G
value, on the other hand, it diminishes the difference in G
value as shown in Fig. 2 except for the case of HDEHP.
Irradiation at standing induces distribution of hydrogen in
the system and takes long time to reach a steady state.
Based on the G values obtained, it is expected that
hydrogen generated in the separation column packed with
the adsorbent will be dissolved into the mobile phase and
discharged to resulting in safety for explosion.
Acknowledgements
We would like to thank Mr. R. Yamagata at Irradiation
Service Section in TARRI for his assistance on the
experiment. Present study is the result of “Development of
Extraction Chromatography for Am and Cm Recovery”
entrusted to JAEA by the Ministry of Education, Culture,
Sports, Science and Technology of Japan (MEXT).
References
1) H. Funasaka and M. Itoh, Global 2007, Boise, USA
(2007) 259.
2) F. J. Miner and J. R. Seed, Chem. Rev., 67, (1967) 299.
G value
1.2
1
0.8
0.6
0.4
0.2
0
CMPO
/SiO -P
2
TODGA
/SiO -P
2
HDEHP
/SiO -P
2
R-BTP
/SiO -P
2
TRPEN
/SiO -P
2
Adsorbents
Fig. 2 G values for the water–adsorbent system at
0.1 g/cm 3 obtained after 1.25 h irradiation. The
adsorbent–water mixture was stirred with Ar
during irradiation.
SiO 2 -P
SiO 2
Water