Site characterization is currently underway to determine the potential suitabili
ID: 3307694 • Letter: S
Question
Site characterization is currently underway to determine the potential suitability of Yucca Mountain, NV as the Nation's civilian high level radioactive waste repository. The current plan is to create an underground repository at a depth of 350 m in partially saturated Topopah Springs volcanic tuffs. The repository will be a series of parallel drifts (tunnels) arranged within a plane at the 350 m elevation each containing steel cannisters of heat-generating waste. The large thermal loading is expected to produce a thermal profile similar to that illustrated, decreasing from about 160° C at the repository horizon to below boiling (98 C) about 100 m away. Assume this to be the maximum dry-out at between 600 and 1000 years. Above the dryout zone, condensate will collect, having been driven by buoyancy of the water vapor in fractures, and then imbibed into the matrix surrounding the fractures. Following the peak thermal loading, the dryout zone will contract as the condensate refluxes to the repository The repository is laterally extensive (700 m × 2800 m) compared to its depth (350 m), so these cal- culations may consider a one-dimensional vertical column. The following calculations are to examine the potential of the overlying fractured tuff to accept the condensate. For the simplified site geometry attached, evaluate the following: 1. Evaluate the volume of water mobilized from the dryout zone if the zone extends approximately 100 m above and below the repository. All water vapor will move upwards. Evaluate this per unit area of the repository and at the repository scale.Explanation / Answer
Since the dryout zone extends 100m above and below the repository, the volume=(700+100)* (2800+100)*350= 800*2900*350=812000000 m3
Volume per unit area of the repository= 812000000/(700*2800)=414.29 m