Modeling of physico-chemical characteristics of mortar-waste mixture in radioactive waste management

Highlights: •All measured results satisfy basic criteria of IAEA. •Results of permeability measurements and mechanical strength are very satisfactory. •Leaching rates of four radionuclides, ¹³⁷Cs through 6 mortar samples are smaller than 4.5 10⁻⁵ (cm²/d). •Results presented in this paper are examples of results obtained in a 20 years mortar and concrete testing project. -- Abstract: An optimization of mortar (as matrix), improved with vermiculite clay, used for immobilization of radionuclide caesium-137 is presented. A relatively simple mathematical model is given, which permits minimization of leach rate and permeability and maximization of compressive strength. An optimal solution, based on experimental data, is given. These results will be used for a future radioactive waste disposal center in Serbia.