Molecular Dynamics Study of the Beryllium Interaction with C-S-H Phases

Abstract

Beryllium has applications in fission and fusion reactors, and accordingly it is expected in specific waste streams in nuclear waste repositories. As a part of the multi-barrier system, cementitious materials were shown to strongly sorb beryllium, but the precise uptake mechanisms remain ill-defined. Computational simulations were used to study Be(II) uptake by calcium-silicate-hydrate (C-S-H) phases. Molecular dynamics (MD) calculations show that Be(II) sorbs on ( 001), (004), and (100) C-S-H surfaces through Ca-bridges and hydrogen bonds. Energy profiles indicate that surface complexes with the highest number of Ca-bridges are the most stable. MD simulations support also Be(II) retention in the C-S-H interlayer. Be(OH) 3− is predominantly bound through the exchange of water molecules for deprotonated silanol groups or through multiple Ca-bridges, whereas Be(OH) 4 2− is immobilized in the interlayer midplane. These results provide key inputs to understand the mechanisms driving Be(II) uptake by cementitious materials of relevance in the context of nuclear waste disposal.

New Insights into Fundamental Processes and Physical Degradation Mechanisms in Rechargeable Lithium‐Oxygen Batteries Providing Suitably High Energy Densities

“…In addition, assessments using in situ mass spectrometry have established that the reaction efficiency of the lithium electrode decreases over time primarily because of the cross‐over of compounds such as H 2 O and CO 2 from the positive oxygen electrode side (Figure 3a). These compounds are considered to be generated as side products of solvent decomposition during positive electrode reaction [8–10] …”