The use of a high-FeO olivine rock as a redox buffer in a nuclear waste repository.
Due to the higher stability of the spent nuclear fuel (mainly composed of UO2) under reducing conditions, and in order to enhance the retention/retardation of some key radionuclides, the olivine rock from the Lovasjärvi intrusion has been proposed as a potential redox-active backfill-additive in deep high-level nuclear waste (HLNW) repositories. In this work, two different approaches have been undertaken in order to establish the redox buffer capacity of olivine rock: (1) The capacity of the rock to respond to changes in pH or pe has been demonstrated and the final (pH, pe) coordinates agree with the control exerted by the system Fe(II)/Fe(III). (2) The rate of consumption of oxygen has been determined at different pH values. These rates are higher than the ones reported in the literature for other solids, what would point to the possibility of using this rock as an additive to the backfill material in a HLNW.
Giménez
J
J
Department of Chemical Eng. (ETSEIB-UPC), Av. Diagonal 647, 08028 Barcelona, Spain. francisco.javier.gimenez@upc.edu
Rovira
M
M
Clarens
F
F
Casas
I
I
Duro
L
L
Grivé
M
M
Bruno
J
J
de Pablo
J
J
D002021:Buffers; D005296:Ferrous Compounds; D055593:Geological Phenomena; D005844:Geology; D006863:Hydrogen-Ion Concentration; D058085:Iron Compounds / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D011850:Radioactive Waste; D017640:Silicates / Q000737:chemistry*; D018505:Waste Management / Q000379:methods; D014878:Water Pollution, Radioactive / Q000517:prevention & control
D002021:Buffers; D005296:Ferrous Compounds; D058085:Iron Compounds; D017616:Magnesium Compounds; D011850:Radioactive Waste; D017640:Silicates; C034475:olivine; C034236:ferrous oxide; D010100:Oxygen