TY - GEN
T1 - Migration behavior of plutonium affected by ferrous ion in compacted bentonite by using electrochemical technique
AU - Akiyama, Daisuke
AU - Idemitsu, Kazuya
AU - Inagaki, Yaohiro
AU - Arima, Tatsumi
AU - Konashi, Kenji
AU - Koyama, Shinichi
N1 - Publisher Copyright:
© 2014 Materials Research Society.
PY - 2014
Y1 - 2014
N2 - The migration behavior of plutonium is expected to be affected by the corrosion products of carbon steel in compacted bentonite at high-level waste repositories. Electrochemical experiments were carried out to simulate the reducing environment created by ferrous iron ions in equilibrium with anoxic corrosion products of iron. The concentration profiles of plutonium could be described by the convection -dispersion equation to obtain two migration parameters: apparent migration velocity Va and apparent dispersion coefficient Da. The apparent migration velocity was evaluated within 1 nm/s and was found to be independent of the experiment duration and the dry density of bentonite in the interval 0.8-1.4 Mg/m3. The apparent dispersion coefficient increased with the experiment duration at a dry density of 1.4 Mg/m3. The results for other dry densities also showed the same trend. These findings indicate that plutonium migration likely starts after ferrous ions reach the plutonium, in other words, the reducing environment due to ferrous ions could change the chemical form of plutonium and/or the characteristics of compacted bentonite. The apparent diffusion coefficient was estimated to be around 0.5 to 2.2 um2/s and increased with decreasing the dry density of bentonite.
AB - The migration behavior of plutonium is expected to be affected by the corrosion products of carbon steel in compacted bentonite at high-level waste repositories. Electrochemical experiments were carried out to simulate the reducing environment created by ferrous iron ions in equilibrium with anoxic corrosion products of iron. The concentration profiles of plutonium could be described by the convection -dispersion equation to obtain two migration parameters: apparent migration velocity Va and apparent dispersion coefficient Da. The apparent migration velocity was evaluated within 1 nm/s and was found to be independent of the experiment duration and the dry density of bentonite in the interval 0.8-1.4 Mg/m3. The apparent dispersion coefficient increased with the experiment duration at a dry density of 1.4 Mg/m3. The results for other dry densities also showed the same trend. These findings indicate that plutonium migration likely starts after ferrous ions reach the plutonium, in other words, the reducing environment due to ferrous ions could change the chemical form of plutonium and/or the characteristics of compacted bentonite. The apparent diffusion coefficient was estimated to be around 0.5 to 2.2 um2/s and increased with decreasing the dry density of bentonite.
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U2 - 10.1557/opl.2014.631
DO - 10.1557/opl.2014.631
M3 - Conference contribution
AN - SCOPUS:84908213523
T3 - Materials Research Society Symposium Proceedings
SP - 79
EP - 84
BT - Scientific Basis for Nuclear Waste Management XXXVII
A2 - Duro, Lara
A2 - Gimenez, Javier
A2 - Casas, Ignasi
A2 - de Pablo, Joan
PB - Materials Research Society
T2 - 37th International Symposium on the Scientific Basis for Nuclear Waste Management
Y2 - 29 September 2013 through 3 October 2013
ER -