For more than
20 years, scientists have performed
thousands of studies at Yucca Mountain,
at prestigious national laboratories
such as Los Alamos, Sandia, Lawrence
Livermore, and Lawrence Berkeley as
well as at the U.S. Geological Survey.
These studies (called site characterization)
were aimed at understanding the mountain's
physical aspects and the processes
that could affect the repository's
safety.
In working to license, construct,
and operate a repository at Yucca
Mountain, we are relying on information gained from our site characterization
studies. Since the first tests at Yucca Mountain in the late 1970s,
the site characterization program evolved into three parallel and
complimentary test programs, which included:
- surface-based testing and investigation
- underground geologic mapping and
testing
- laboratory material testing and
modeling
To facilitate testing, we drilled
over 450 surface boreholes and collected
over 75,000 feet of rock core from
the boreholes; excavated over 200
pits and trenches; excavated over
6.8 miles of underground
tunnels and 13 test areas; and
constructed a complex of three deep
wells. We developed the largest known
heater test;
conducted chemical and mechanical
tests on thousands of rock, water,
and man-made materials; conducted
hundreds of solubility and colloid
tests on long-life radionuclides;
conducted air and liquid infiltration
tests; and investigated natural
analogues
from around the world.
Using the results of our scientific
studies, engineers designed repository
systems that would work with the mountain's
natural environment to isolate the
waste.
Using computer modeling and other
sophisticated analysis methods, we
evaluated the potential repository's
ability to protect people and the
environment for thousands of years
in the future (called Total
System Performance Assessment).
In 2002, we completed our site characterization
activities. Also that year, Congress
and the President approved the development
of a geologic repository at Yucca
Mountain. These approvals were based
on two extensive scientific reports:
- The Yucca Mountain Science and Engineering
Report, which describes
the science and engineering completed
during site characterization activities
- The Yucca
Mountain Site Suitability Evaluation,
which describes the information
that supported the Secretary of
Energy's evaluation of whether Yucca
Mountain is a suitable site for
a repository
Site designation by Congress and
the President was an intermediate
step in the development of a repository
at Yucca Mountain. Currently, we are
working on the next step, which is
to complete the technical work required
for an application to the U.S.
Nuclear Regulatory Commission
for a license to construct and eventually operate
the repository.
Our license application must present a scientifically
defensible position that we can construct,
operate, and close a repository without
unreasonable risk to people and the
environment.
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