Following the formation of ThO2 nanoparticles with HEXS and SAXS

Actinide nanoparticles are raising considerable concern in the field of safe nuclear waste disposal. It has been demonstrated that actinide nanoparticles are a mean of geochemical transport of radioactive material in natural aquatic systems. Currently, the chemistry and reactivity of actinide nanoparticles is very poorly known and the present proposal looks in the direction of filling this gap. ThO2 is used as model for AnO2 and is the reasonable system to start with. The objective of this measurement campaign will be to investigate the formation mechanism of ThO2 nanoparticles prepared by solution chemistry by thoroughly characterizing the structure of the products formed during the precipitation process. We will investigate the influence of thorium stock solution concentration, pH, post-synthesis thermal treatment and aging on ThO2 nanoparticles size and crystallinity. The results will shed light on the synthesis conditions that favor nanoparticle formations and growth.