Modelling of bituminized radioactive waste leaching. Part I: Constitutive equations

This paper presents theoretical work aiming at studying the behaviour of leached bituminized waste materials and the development of a saline solution-filled pore structure (called permeable layer) in the material. In Part I of this paper, the constitutive model COLONBO which describes mathematically the evolution of the pore structure, the water uptake, the salt and RN release of leached bituminized waste is presented. By the introduction of adequate simplifications, an analytical solution of the problem is obtained which gives the main relations between measurable leaching indicators (water uptake, soluble salt release, porosity profiles and apparent thickness of the permeable layer) and material (soluble salt content, bituminized waste density) or environmental parameters (chemical activity of water in the leachant). In the companion paper (Part II), the validity of these relations is investigated experimentally.