Thermal stress modeling of in situ vitrified barriers for hazardous waste containment

Development of In Situ Vitrification technology has included the concept of subsurface barriers. Structural integrity of vitrified soil bodies is important to barrier performance. Analytical methods are under development for predicting thermal-structural performance during melt cooldown. A thermal modeling capability has been developed for predicting the cooling transient of subsurface molten masses using the finite element method. A computationally efficient instant freezing model'' was demonstrated to give qualitative agreement for predicted stresses with a more sophisticated creep model. A method for predicting stress relief due to cracking, as a preliminary step to predicting crack densities, has been demonstrated. 8 refs., 10 figs