Environmental Engineering Reference
In-Depth Information
from what is not. A commonly used source-defined classification system (defined
by the source of the waste rather than by measurable quality of the waste) is
summarized as follows:
•
High-Level Waste (HLW).
The NRC description of HLW includes (1)
the highly radioactive material resulting from the reprocessing of spent
nuclear fuel, including liquid waste produced directly in reprocessing and
any solid material originating from such liquid waste that contains fission
products in sufficient concentrations, and (2) other highly radioactive
material that the Commission, in accordance with existing law, determines
by rule requires permanent isolation.
12
The Commission has determined
that irradiated reactor fuel shall, for the purposes of the repository, be
considered as HLW.
13
•
Spent Nuclear Fuel (SNF).
SNF is the fuel that has been withdrawn from
a nuclear reactor following irradiation, the constituent elements of which
have not been separated by reprocessing.
13
It is worth noting that spent
nuclear fuel is regulated as HLW under 10 CFR 60.
•
Transuranic Waste (TRU).
TRU elements are those having atomic num-
bers greater than 92 (i.e., having more protons than uranium). In the United
States, TRU waste is defined as radioactive waste that is not classified as
HLW, but contains an activity of more than 100 nCi/g from alpha-emitting
TRU isotopes having half-lives greater than 20 years.
14
Typical waste
includes metal tools, lab coats, gloves, equipment, debris, and so on
contaminated with plutonium during laboratory and facility operations.
15
Much of the TRU contains sufficiently high concentrations of gamma-
emitting nuclides that necessitate remote handling. Most TRU wastes
contain primarily alpha-emitters which are safe for contact handling when
packaged. As a result of long half-lives of TRU waste, the most suitable
method for disposal is isolation in geologic repositories.
•
By-Product Materials.
including uranium mining and mill tailings. The
by-product materials include (1) any radioactive material (except special
nuclear material) yielded in or made radioactive by exposure to the radi-
ation occurrences, or to the process of producing or utilizing special
nuclear material, and (2) the tailings or wastes produced by the extraction
or concentration of uranium or thorium from any ore processed primarily
for its source material content.
16
The tailings or wastes produced by the
extraction or concentration of uranium or thorium from any ore processed
primarily for its source material content are also called by-product mate-
rials under 42 U.S.C. 2014.
•
Low-Level Waste (LLW).
LLW is defined by the Low-Level Radioactive
Waste Policy Act (LLWPA) as radioactive material that (1) is not classified
as high-level waste, transuranic waste, spent nuclear fuel, or mill tailings;
and (2) the NRC, in accordance with existing law and consistent with part
(1).
16
LLW often contains small amounts of radioactivity dispersed in
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