Environmental Engineering Reference
In-Depth Information
3.2.4
S PECIAL W ASTES
Some wastes do not come under the regulation of RCRA but are still considered to
be hazardous. They are polychlorinated biphenyls (PCBs), asbestos, and radionu-
clides. 7 PCBs and asbestos are regulated under the Toxic Substances Control Act
(TSCA). 8 Radionuclides are regulated as radioactive waste under the AEA.
3.3
C LASSIFICATION AND CHARACTERIZATION OF
RADIOACTIVE WASTES
Radioactive wastes arise in many forms from a wide range of activities, most notably
from plants and processes associated with nuclear power research and production,
and with military applications. Large numbers of industrial, research, and medical
uses of radioactive materials also give rise to wastes, albeit in total on a relatively
small scale and in most cases giving rise to only small volumes, containing small
amounts and low concentrations of activity.
3.3.1
R ADIOACTIVE W ASTE C LASSIFICATION
3.3.1.1
Background
The objectives of classification are to facilitate understanding and simplify manage-
ment of the multiple elements of a diverse system. 9 Waste classes were based
primarily on practical factors of immediate concern, such as exposure rates and
proliferation security, or on the process that produced the waste. For the purpose of
constructing a reasonable classification system of radioactive waste, the number of
classes is desired to be as low as possible, while diversity is retained to promote
proper management. There are some different classification schemes based on dif-
ferent purposes. The first official distinction between different kinds of radioactive
waste was between high-level waste (aqueous waste from the first-cycle solvent-
extraction in reprocessing spent nuclear fuel) and “other than high level” waste. 10
After several years of development, the classification system has become more
complicated and diversified.
3.3.1.2
Radioactive Waste Classification
Most nations categorize wastes into different classes for simplifying waste manage-
ment actions, rules, and regulations while protecting human health. An acceptable
classification and characterization system should depend on a reasonable definition
of radioactive waste. The DOE defines radioactive waste as solid, liquid, or gaseous
material that contains radionuclides regulated under the AEA, and of negligible
economic value considering costs of recovery. 11
Rather than having a common basis for each waste class in its classification
system, such as a set of classes based on a combination of the half-life, gas produc-
tion, and heat generation rate, the U.S. system has some classes that participate on
one basis and others that partake another. A number of waste and material classes
have been specified in AEA, which does not clearly distinguish what is regulated
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