Abstract
Spent nuclear fuel contains substantial amounts of long lived isotopes of actinide elements e.g. neptunium-237. The behaviour of these isotopes in repository environments and migration in deep geological formations must be well known for realistic safety assessments. In this work the redox and sorption behaviour of neptunium was studied with laboratory experiments simulating conditions in deep crystalline rock formations. Under oxic conditions the sorption of Np(V) on tonalite was independent of the initial Np-concentration (5 x -10{sup -}1{sup 2} to 5 x 10{sup -}8 M) indicating an exchange type sorption mechanism. In unoxic water-rock-system the Np(V) was reduced to Np(IV) by components of the waters. Sorption of Np(V) on mineral surface slowered the reduction to Np(IV). Even under highly reducing environments the sorbed phases were of mixtures of Np (IV) and Np(V). After initial reduction to Np(IV) the oxidation of part of neptunium to Np(V) was not followed by dissolution of Np(V). The solubility of neptunium in reducing groundwater was smaller than or equal to 10{sup -}1{sup 3} M. Sorption of neptunium with initial Np-concentration of 10{sup -}1{sup 4} M on polished rock surfaces indicated a Ka-value about 100 x 10{sup -}4 m{sup 3}/m{sup 2}. (orig.).
Hakanen, M;
[1]
Lindberg, A
[2]
- Helsinki Univ. (Finland). Dept. of Radiochemistry
- Geological Survey of Finland, Helsinki (Finland)
Citation Formats
Hakanen, M, and Lindberg, A.
Behaviour of neptunium in deep groundwater environments.
Finland: N. p.,
1989.
Web.
Hakanen, M, & Lindberg, A.
Behaviour of neptunium in deep groundwater environments.
Finland.
Hakanen, M, and Lindberg, A.
1989.
"Behaviour of neptunium in deep groundwater environments."
Finland.
@misc{etde_10119254,
title = {Behaviour of neptunium in deep groundwater environments}
author = {Hakanen, M, and Lindberg, A}
abstractNote = {Spent nuclear fuel contains substantial amounts of long lived isotopes of actinide elements e.g. neptunium-237. The behaviour of these isotopes in repository environments and migration in deep geological formations must be well known for realistic safety assessments. In this work the redox and sorption behaviour of neptunium was studied with laboratory experiments simulating conditions in deep crystalline rock formations. Under oxic conditions the sorption of Np(V) on tonalite was independent of the initial Np-concentration (5 x -10{sup -}1{sup 2} to 5 x 10{sup -}8 M) indicating an exchange type sorption mechanism. In unoxic water-rock-system the Np(V) was reduced to Np(IV) by components of the waters. Sorption of Np(V) on mineral surface slowered the reduction to Np(IV). Even under highly reducing environments the sorbed phases were of mixtures of Np (IV) and Np(V). After initial reduction to Np(IV) the oxidation of part of neptunium to Np(V) was not followed by dissolution of Np(V). The solubility of neptunium in reducing groundwater was smaller than or equal to 10{sup -}1{sup 3} M. Sorption of neptunium with initial Np-concentration of 10{sup -}1{sup 4} M on polished rock surfaces indicated a Ka-value about 100 x 10{sup -}4 m{sup 3}/m{sup 2}. (orig.).}
place = {Finland}
year = {1989}
month = {Dec}
}
title = {Behaviour of neptunium in deep groundwater environments}
author = {Hakanen, M, and Lindberg, A}
abstractNote = {Spent nuclear fuel contains substantial amounts of long lived isotopes of actinide elements e.g. neptunium-237. The behaviour of these isotopes in repository environments and migration in deep geological formations must be well known for realistic safety assessments. In this work the redox and sorption behaviour of neptunium was studied with laboratory experiments simulating conditions in deep crystalline rock formations. Under oxic conditions the sorption of Np(V) on tonalite was independent of the initial Np-concentration (5 x -10{sup -}1{sup 2} to 5 x 10{sup -}8 M) indicating an exchange type sorption mechanism. In unoxic water-rock-system the Np(V) was reduced to Np(IV) by components of the waters. Sorption of Np(V) on mineral surface slowered the reduction to Np(IV). Even under highly reducing environments the sorbed phases were of mixtures of Np (IV) and Np(V). After initial reduction to Np(IV) the oxidation of part of neptunium to Np(V) was not followed by dissolution of Np(V). The solubility of neptunium in reducing groundwater was smaller than or equal to 10{sup -}1{sup 3} M. Sorption of neptunium with initial Np-concentration of 10{sup -}1{sup 4} M on polished rock surfaces indicated a Ka-value about 100 x 10{sup -}4 m{sup 3}/m{sup 2}. (orig.).}
place = {Finland}
year = {1989}
month = {Dec}
}