Preliminary studies of gas phase flow effects and moisture migration at Yucca Mountain, Nevada.

摘要

The Yucca Mountain project is investigating the feasibility of siting a repository for high-level nuclear wastes at Yucca Mountain. Part of these investigations include estimates of the release of radionuclides to the accessible environment. Most of the radionuclides of interest will be transported in groundwater but a few radionuclides such as C(sup 14) could be transmitted through gaseous pathways. An understanding of gas phase flow effects is necessary for determining the quantity of gaseous radionuclides such as C(sup 14) that could be released at the surface. Gas phase flow has other ramifications besides providing potential pathways for radionuclides to the accessible environment. Through vaporization and condensation processes coupled with vapor transport, gas phase flow effects may indirectly influence the distribution of moisture and liquid phase flow throughout the unsaturated zone. Of paramount importance for an analysis of these coupled gas and liquid flow effects are the boundary conditions at the land surface. One can foresee that a number of factors at the boundary may play a role in affecting the gas movement and liquid infiltration in the mountain. These factors include: gas barometric pressure, temperature, precipitation, wind velocity, relative humidity of the atmospheric air, and topography of the mountain. The purpose of this work is to consider and understand the possible physical processes involving the physical parameters listed above, and to make simple estimates of the magnitude of these processes. We shall focus primarily on barometric pressure and relative humidity effects. 40 refs.