Studying the migration behaviour of selenate in Boom Clay by electromigration

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Studying the migration behaviour of selenate in Boom Clay by electromigration. / Maes, Norbert; Beauwens, Thomas; De Cannière, Pierre; Moors, Hugo; Wang, Lian.

In: Engineering Geology, Vol. 77, No. Nos. 3-4, 2005, p. 285-293.

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@article{4012de0397904c179971db8ed5558594,
title = "Studying the migration behaviour of selenate in Boom Clay by electromigration",
abstract = "For the disposal of High Level Waste (HLW) in a deep geological formation as Boom Clay, safety assessment studies have shown that long lived 79Se is one of the more critical fission products. Therefore, the knowledge of its migration properties (diffusion, retention) through the geological barrier (Boom Clay) is of paramount importance. The migration behaviour of selenium strongly depends on its speciation. Under reducing conditions, selenide would be the dominant species and selenium migration would mainly be controlled by the low solubility of Se(-II)-bearing minerals. However Se species are often found in redox disequilibrium and more oxidized species might also coexist. Therefore, the study of selenate migration requires attention, as it might be the most mobile selenium species in the host rock. Electromigration experiments performed with a 75Se-labeled selenate in Boom Clay indicate a high mobility for this species. The apparent diffusion coefficient (Dapp) of selenate in Boom Clay is estimated from electromigration experiments performed under different electric fields. Using two independent approaches, the value of Dapp for selenate is shown to fall in the range 1.7 × 10-11 to 6.2 × 10-11 m² s-1. Moreover, no reduction of selenate in Boom Clay was observed.",
keywords = "electromigration, diffusion coefficients, selenium, speciation, Boom Clay, radioactive waste",
author = "Norbert Maes and Thomas Beauwens and {De Canni{\`e}re}, Pierre and Hugo Moors and Lian Wang",
note = "Score = 10",
year = "2005",
doi = "10.1016/j.enggeo.2004.07.019",
language = "English",
volume = "77",
pages = "285--293",
journal = "Engineering Geology",
issn = "0013-7952",
publisher = "Elsevier",
number = "Nos. 3-4",

}

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TY - JOUR

T1 - Studying the migration behaviour of selenate in Boom Clay by electromigration

AU - Maes, Norbert

AU - Beauwens, Thomas

AU - De Cannière, Pierre

AU - Moors, Hugo

AU - Wang, Lian

N1 - Score = 10

PY - 2005

Y1 - 2005

N2 - For the disposal of High Level Waste (HLW) in a deep geological formation as Boom Clay, safety assessment studies have shown that long lived 79Se is one of the more critical fission products. Therefore, the knowledge of its migration properties (diffusion, retention) through the geological barrier (Boom Clay) is of paramount importance. The migration behaviour of selenium strongly depends on its speciation. Under reducing conditions, selenide would be the dominant species and selenium migration would mainly be controlled by the low solubility of Se(-II)-bearing minerals. However Se species are often found in redox disequilibrium and more oxidized species might also coexist. Therefore, the study of selenate migration requires attention, as it might be the most mobile selenium species in the host rock. Electromigration experiments performed with a 75Se-labeled selenate in Boom Clay indicate a high mobility for this species. The apparent diffusion coefficient (Dapp) of selenate in Boom Clay is estimated from electromigration experiments performed under different electric fields. Using two independent approaches, the value of Dapp for selenate is shown to fall in the range 1.7 × 10-11 to 6.2 × 10-11 m² s-1. Moreover, no reduction of selenate in Boom Clay was observed.

AB - For the disposal of High Level Waste (HLW) in a deep geological formation as Boom Clay, safety assessment studies have shown that long lived 79Se is one of the more critical fission products. Therefore, the knowledge of its migration properties (diffusion, retention) through the geological barrier (Boom Clay) is of paramount importance. The migration behaviour of selenium strongly depends on its speciation. Under reducing conditions, selenide would be the dominant species and selenium migration would mainly be controlled by the low solubility of Se(-II)-bearing minerals. However Se species are often found in redox disequilibrium and more oxidized species might also coexist. Therefore, the study of selenate migration requires attention, as it might be the most mobile selenium species in the host rock. Electromigration experiments performed with a 75Se-labeled selenate in Boom Clay indicate a high mobility for this species. The apparent diffusion coefficient (Dapp) of selenate in Boom Clay is estimated from electromigration experiments performed under different electric fields. Using two independent approaches, the value of Dapp for selenate is shown to fall in the range 1.7 × 10-11 to 6.2 × 10-11 m² s-1. Moreover, no reduction of selenate in Boom Clay was observed.

KW - electromigration

KW - diffusion coefficients

KW - selenium

KW - speciation

KW - Boom Clay

KW - radioactive waste

UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/ezp_27230

UR - http://knowledgecentre.sckcen.be/so2/bibref/2407

U2 - 10.1016/j.enggeo.2004.07.019

DO - 10.1016/j.enggeo.2004.07.019

M3 - Article

VL - 77

SP - 285

EP - 293

JO - Engineering Geology

JF - Engineering Geology

SN - 0013-7952

IS - Nos. 3-4

ER -

ID: 200028