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

5.21
conducted in four steps: national screening surveys, whose objective is to identify places
that have some potential for waste isolation; regional studies, which evaluate a specific
region of interest; area studies, which are conducted to characterize the areas of interest
described by the regional study; and location studies, which further narrow the scope of the
investigation to a site or sites.
Individual investigations are in various stages of the site-characterization process.
Current investigations include 1) the Gulf Interior Region salt domes, 2) the Paradox Basin,
3) the Permian Basin, 4) the Salina Basin, 5) basalt flows at the DOE's Hanford Site, and
6) DOE's Nevada Test Site. Because of the generic nature of this Statement, details of
site-specific studies are not included; for details regarding regional studies, the reader
is referred to DOE's position statement to the NRC Confidence Rulemaking (DOE/NE-0007).
5.2.2 Waste Package Systems
Package components consist of the waste form, stabilizer, canister, overpack, sleeve,
and backfill (Section 5.1.2).
Testing and development studies on various individual barrier components of the waste
package system under expected conditions of geologic isolation have been in progress for
several years. These studies have been conducted in industrial and national laboratories,
as well as universities, both in this country and abroad. Most of these studies are not
complete, but data and results generated during the past few years do indicate that compo-
nents of the waste package system can prevent or minimize release of radionuclides to the
natural system by functioning as effective chemical and physical barriers. Programs, pro-
gram plans, and results are described in DOE/NE-0007 (DOE 1980).
Because of the many candidate materials for the waste package, package development pro-
grams will proceed in a logical sequence of scale and complexity. The following sequence
of testing is planned:
* Initial laboratory testing using simulated waste
* Laboratory testing using real waste
* Large-scale testing in the field involving all components of the waste package.
Various aspects of the above tests have been described by the U.S. Geological Survey
and DOE in the Earth Science Technical Plan (ONWI 1980), which discusses the types of data
required and the sequence of laboratory, large-scale engineering, and field demonstration
tests.
5.2.2.1 Waste Form
Presently, DOE has experience with spent fuel and glass as waste forms. In order to
determine whether present-day spent fuel can be expected to behave satisfactorily in a geo-
chemical environment, studies are being conducted to determine whether the release rates of
waste nuclides are controlled by diffusion from U0 2 when the oxygen content of water is held
to very low values (ONWI 1979). To date the information obtained from such experiments
indicates that lowering the oxygen content of the water can significantly decrease the