The KOLLORADO-e3 project focuses on the erosion stability of compacted bentonite (geotechnical barrier) as a function of the contact water chemistry/hydraulics and the formation of near-field colloids/nanoparticles as potential carriers for actinides/radionuclides. Both, a detailed experimental program quantifying the bentonite erosion and investigating the influence of surface roughness/charge heterogeneity on nanoparticle mobility and actinide bentonite nanoparticle sorption reversibility, as well as approaches to implement the acquired process understanding in reactive transport modelling codes comprise the project activities.