Radionuclide transport in fractured chalk under abrupt changes in salinity.

Internationally, it has been agreed that geologic repositories for spent fuel and radioactive waste are considered the internationally agreed upon solution for intermediate and long-term disposal. In countries where traditional nuclear waste repository host rocks (e.g.

Colloid-facilitated transport of Pu, U and Cs through fractured chalk: Laboratory experiments, modelling, and implications for nuclear waste disposal.

The influence of montmorillonite colloids on the mobility of Pu, U and Cs through a chalk fracture was investigated to assess the transport potential for radioactive waste. Radioisotopes of each element, along with the conservative tracer tritium, were injected in the presence and absence of montmorillonite colloids into a naturally fractured chalk core. In parallel, batch experiments were conducted to obtain experimental sorption coefficients (K, mL/g) for both montmorillonite colloids and the chalk fracture material.

Mobility of Radionuclides in Fractured Carbonate Rocks: Lessons from a Field-Scale Transport Experiment.

Current research on radionuclide disposal is mostly conducted in granite, clay, saltstone, or volcanic tuff formations. These rock types are not always available to host a geological repository in every nuclear waste-generating country, but carbonate rocks may serve as a potential alternative. To assess their feasibility, a forced gradient cross-borehole tracer experiment was conducted in a saturated fractured chalk formation.

Radionuclide transport in brackish water through chalk fractures.

Mobility of radionuclides originating from geological repositories in the subsurface has been shown to be facilitated by clay colloids. In brackish water, however, colloids may flocculate and act to immobilize radionuclides associated with them. Furthermore, little research has been conducted on radionuclide interactions with carbonate rocks.

Interaction between spent fuel components and carbonate rocks.

Deep geological repository is considered the internationally accepted method for spent fuel (SF) disposal. In countries where salt, clay, tuff and granite are unavailable at geologically suitable area, other rock types may come into consideration. In Israel, carbonate rocks make up a significant portion of the surface and subsurface lithologies, thus, low permeability carbonates were evaluated as possible host rocks for a repository, and for an interim storage facility.