<p>Brittle material, such as ceramics, are characterized by a complex crack behavior which undergo crack propagation, impact of discontinuities on thermal transfer and eventually healing phenomena that restore the material rigidity. In the context of healing by material diffusion welding, an original damage-healing thermo-mechanical cohesive zone model is proposed. The introduction of an internal variable to model the physical-chemical process that can induce healing phenomena, called healing reserve, is employed to partially restore cracks. Crack initiation and propagation are modelled through a damage variable. The evolution laws for both internal variables have been carefully selected to guarantee compliance with the principles of thermodynamics. Academic applications are performed to illustrate the model behavior under structural simulation. The aforementioned application enables the demonstration of the impact of certain pivotal parameters such as mixed-modes control and the viscosity parameters. Subsequently, a simulation of a nuclear fuel pellet undergoing a single irradiation cycle was conducted to reproduce the healing process observed in post-irradiation examinations. The studies highlight the ability of the model to address complex and diverse phenomena.</p>