 |
 |
|
|
|
The results of extensive underground tests indicate that very little water could seep into the repository tunnels. Instead, most water flows around the openings. Click the image to enlarge.
|
|
|
|
Emplacement
tunnels, also referred to as “drifts,”
are the specially constructed horizontal
openings where the waste will be placed
for disposal. The current design includes
approximately 108 emplacement tunnels.
These tunnels would be excavated
in solid rock about 1,000 feet beneath
the surface of the mountain and,
on average, about 1,000 feet above
the water table. The tunnels would
be 18 feet in diameter, various
lengths, and about 250 feet apart.
They would be lined with perforated steel plates held in place by rock bolts to prevent rock from falling on the
engineered features.
The underground location and the orientation of the emplacement tunnels are based on the following factors:
- thickness of the overlying rock and soil
- characteristics of the rock itself (such as porosity)
- location of the fractures in the rock
- distance from possible earthquake faults
- depth to the water table
- distance from other underground features
Experts designed the underground layout of the emplacement tunnels to manage the heat that would be generated by the waste. This heat will influence moisture in the rock, humidity in the tunnels, and other conditions within the repository. In addition, the tunnels are designed so that any water that enters them will drain, by gravity, downward and away from the repository.
Although the location and geology
of Yucca Mountain allows only a minute
amount of water to filter through
the mountain, engineers have designed
systems to combat any seepage that
could reach the radioactive waste container.
Thick, stainless steel waste packages with an outer nickel alloy shell and a drip shield to protect the packages from exposure to water work together to safely isolate radioactive waste.
- Waste packages for Yucca Mountain
will be designed to withstand the
geologic conditions of the repository.
- Drip shields protect the waste
package from exposure to water and rockfall.
- Tunnel inverts form a platform
to support the waste package while
also slowing down the movement of water
into the rock below.
Last reviewed: 04/08
Repository Engineering and Design Overview:
|
