JAEA-Review-2010-065.pdf:15.99MB - 日本原子力研究開発機構
JAEA-Review-2010-065.pdf:15.99MB - 日本原子力研究開発機構
JAEA-Review-2010-065.pdf:15.99MB - 日本原子力研究開発機構
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Study on Stability of Cs·Sr Solvent Impregnate Resin<br />
against Gamma Irradiation<br />
H. Hoshi a) , T. Kikuchi a) , Y. Morita a) and T. Kimura b)<br />
a) Division of Fuels and Materials Engineering, NSED, <strong>JAEA</strong>,<br />
b) Division of Environment and Radiation Sciences, NSED, <strong>JAEA</strong><br />
Minimization of radioactive waste from reprocessing<br />
process of spent nuclear fuel is strongly desired. We have<br />
developed an advanced technology for separation of heat<br />
generating elements (Cs and Sr) from high level waste to<br />
optimize radioactive waste by its characteristics. Recently,<br />
some analogues of calix-crown or crown ether extractant<br />
were reported on specific selectivity for Cs or Sr,<br />
respectively 1,2) . In our previous study, prepared adsorbents<br />
indicated promising ability to separate Cs and Sr from other<br />
typical fission products dissolved in nitric acid solution;<br />
besides they maintained significant selectivity for Cs or Sr<br />
after gamma irradiation. Decreasing ratio of static<br />
adsorption capacity by irradiation was also estimated. In this<br />
work, gamma irradiation effect on dynamic adsorption<br />
capacity was examined for the conceptual designing.<br />
An extractant and a modifier were impregnated into<br />
porous silica, which is embedded styrene divinyl benzene<br />
polymer on the surface. These adsorbents contacting with<br />
nitric acid solution were exposed to gamma ray in a vial.<br />
The dynamic adsorption capacity was examined by using<br />
irradiated adsorbents. The irradiated adsorbent was packed<br />
in a glass column as slurry state. After the packed column<br />
was filled with 3 M HNO 3, a break through curve was<br />
obtained by feeding HNO 3 solution containing 10 mM Cs or<br />
Sr.<br />
Initial dynamic adsorption capacity was estimated in<br />
advance and was 70.2 mmol/L, which was obtained by the<br />
product of Cs concentration and the difference between the<br />
break through point and the dead volume. Figure 1 shows<br />
[Cs] / mM<br />
1-15<br />
10<br />
8<br />
6<br />
4<br />
2<br />
Dead<br />
volume<br />
0<br />
0 10 20 30 40 50 60<br />
Effluent volume / cm 3<br />
54.9 cm 3<br />
Fig. 1 Breakthrough curve of Cs adsorbent after gamma<br />
irradiation. Dose rate: 1.82 kGy/h; duration: 16 h;<br />
Dose: 29.1 kGy; soaked in 3 M HNO3. Column: i.d.<br />
10 mm × 100 mm height (bed height: 82 mm); flow<br />
rate: 1 cm 3 /min; mobile phase: 10 mM Cs-3 M HNO3. <strong>JAEA</strong>-<strong>Review</strong> <strong>2010</strong>-065<br />
the break through curve of Cs adsorbent, which was<br />
irradiated 29.1 kGy in 3 M HNO 3. The breakthrough point<br />
was estimated at 54.9 cm 3 by linear regression (dotted line).<br />
The dynamic adsorption capacity of irradiated adsorbent<br />
was 73.5 mmol/L, which was almost as same as initial one.<br />
This result indicated that this adsorbent has rather high<br />
stability against gamma irradiation.<br />
Figure 2 shows the break through curve of Sr adsorbent,<br />
which was irradiated 29.1 kGy in 3 M HNO 3. While initial<br />
dynamic adsorption capacity was 125 mmol/L, that of<br />
irradiated adsorbent was 87.1 mmol/L; the dynamic<br />
adsorption capacity decreased by around 30%. Thus, some<br />
refinement of process design will be required.<br />
It is concluded that Cs adsorbent maintained its dynamic<br />
adsorption capacity and Sr adsorbent kept 70% of initial<br />
capacity. Decreasing ratio of dynamic adsorption capacity<br />
by irradiation can be estimated from these results. It<br />
contributes significantly for the conceptual design of<br />
separation plant.<br />
Present study is the result of “Development of separation<br />
technology of transuranium elements and fission products<br />
by using new extractants and adsorbents” entrusted to <strong>JAEA</strong><br />
by the Ministry of Education, Culture, Sports, Science and<br />
Technology of Japan (MEXT). We are very grateful to<br />
Mr. Yamagata for his valuable cooperation in this study.<br />
References<br />
1) P. V. Bonnesen et al., Solve. Extr. Ion Exch. 18 (2000)<br />
1079.<br />
2) J. F. Dozol et al., EUR 19605EN, 2000.<br />
[Sr] / mM<br />
- 19 -<br />
10<br />
8<br />
6<br />
4<br />
2<br />
Dead<br />
volume<br />
62.3 cm 3<br />
0<br />
0 10 20 30 40 50 60 70 80<br />
Effluent volume / cm 3<br />
Fig. 2 Breakthrough curve of Sr adsorbent after gamma<br />
irradiation. Dose rate: 1.82 kGy/h; duration: 16 h;<br />
Dose: 29.1 kGy; soaked in 3 M HNO3. Column i.d.:<br />
10 mm × 100 mm height (bed height: 80 mm); flow<br />
rate: 1 cm 3 /min; aq. phase: 10 mM Sr-3 M HNO3.