Management of Commercially Generated Radioactive Waste - U.S. ...

5.15
Specific topics elaborating on site selection criteria and the supporting R&D addres-
sing these matters are discussed below. Supporting R&D projects are listed by organization
in Appendix L of Volume 2.
5.2.1.1 Methods for Regional Geologic Studies
Geologic studies will identify, for a specific region, area and site, the current state
of stability and the geologic processes which have acted in the past. Based on this infor-
mation along with repository design, the projection and probability for the future stability
of the specific site will be estimated (see Appendix L).
General geologic conditions in the United States are well known and have been exten-
sively described (Geologic Society of America, current listings). Exploration for mineral
resources--notably oil, gas, coal, and metals--by private industry provides much information
about sub-surface geologic conditions, in many instances to depths approaching 10,000 m (Am.
Assoc. of Petroleum Geologists, current listing). The construction of nuclear reactors,
which must meet stringent licensing requirements, has resulted in detailed geologic evalua-
tions of areas in the Eastern, Midwestern, and Far Western United States (FUGRO, Inc.,
1977). Moreover, various universities have developed as centers of detailed geologic infor-
mation on specific subjects. The accumulated knowledge is sufficient to identify areas in
the United States that meet many of the requirements (Section 5.2.1) for radioactive waste
repositories.
5.2.1.2 Methods for Site Analysis
In general, geologic studies are the mechanism by which available data about the sub-
surface environment are synthesized and coordinated to assess whether the stratigraphic and
structural settings of a proposed site are suitable for a waste repository. Remote sensing
and geophysical studies are conducted to support this activity. Geologic interpretations
are the basis for defining models by which the hydrologic, geologic, geochemical, thermal,
and mechanical characteristics of a repository are assessed.
Geophysical Surveys
Geophysical surveys are an integral part of site selection and characterization
studies. Many of the geophysical techniques utilized by the petroleum and mineral indus-
tries have been applied to the search for geologic repositories. The broad categories of
exploration geophysics summarized in this subsection are gravity, magnetic, electrical, and
seismic methods. In addition, well logging and borehole geophysics are discussed.
There currently exists a wide variety of geophysical techniques available for site
selection and characterization. Geophysical surveys are a well established part of explora-
tion prospecting and proper evaluation can provide extensive information about subsurface
geologic conditions. Such surveys are especially valuable in repository investigations
because they permit investigation of subsurface conditions without extensive drilling.