Numerical studies of heat transfer and gas migration processes in relation to in situ vitrification

摘要

This document presents numerical studies conducted in support of the In Situ Vitrification (ISV) treatability study. These results will be used for support of hardware design and performance assessments of ISV processes. Four models are presented and analyzed using finite element techniques: (1) heat transport and melting during the ISV process, (2) heat transfer calculations on the Intermediate Field Test (IFT) off-gas confinement hood, (3) gas migration in permeable soil surrounding the vitrified zone, and (4) melt rate calculations. Heat transport in the ISV process describes the temperature field and melt growth in the soil. Thermal radiation heat transfer calculations for the IFT hood demonstrate the sensitivity of the hood temperatures to melt temperature, melt radius, and exterior hood emissivity. The study of gas migration in permeable soil resulting from a buried source predicts that gas may migrate to the soil surface. The one-dimensional melt rate calculations conservatively predict a melt rate of 6 cm/hr. 11 refs., 20 figs., 3 tabs.