Skip to Main content Skip to Navigation
Journal articles

Reactivity of nitrate and organic acids at the concrete-bitumen interface of a nuclear waste repository cell

Abstract : This study investigates the fate of nitrate and organic acids at the bitumen-concrete interface within repository cell for long-lived, intermediate-level, radioactive wastes. The interface was simulated by a multiphase system in which cementitious matrices (CEM V cement paste specimens) were exposed to bitumen model leachates consisting of nitrates and acetic acid with and without oxalic acid, chemical compounds likely to be released by bitumen. Leaching experiments were conducted with daily renewal of the solutions in order to accelerate reactions. The concentrations of anions (acetate, oxalate, nitrate, and nitrite) and cations (calcium, potassium) and the pH were monitored over time. Mineralogical changes of the cementitious matrices were analysed by XRD. The results confirmed the stability of nitrates in the abiotic conditions of the experiments. The action of acetic acid on the cementitious matrix was similar to that of ordinary leaching in the absence of organic acids (i.e. carried out with water or strong acids); no specific interaction was detected between acetate and cementitious cations. The reaction of oxalic acid with the cementitious phases led to the precipitation of calcium oxalate salts in the outer layer of the matrix. The concentration of oxalate was reduced by 65% inside the leaching medium. (C) 2013 Elsevier B.V. All rights reserved.
Document type :
Journal articles
Complete list of metadata

https://hal.insa-toulouse.fr/hal-01850751
Contributor : Insa Toulouse Scd <>
Submitted on : Friday, July 27, 2018 - 5:08:02 PM
Last modification on : Wednesday, March 31, 2021 - 8:50:06 AM

Links full text

Identifiers

Citation

Alexandra Bertron, Nicolas Jacquemet, B. Erable, C. Sablayrolles, Gilles Escadeillas, et al.. Reactivity of nitrate and organic acids at the concrete-bitumen interface of a nuclear waste repository cell. Nuclear Engineering and Design, Elsevier, 2014, 268, pp.51--57. ⟨10.1016/j.nucengdes.2013.11.085⟩. ⟨hal-01850751⟩

Share

Metrics

Record views

136