Classification and Characterization of Hazardous, Radioactive, and Mixed Wastes - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 41

large amounts of material. It is mainly generated by uranium enrichment
processes, reactor operations, isotope production, and medical and
research activities. 17

• Naturally Occurring and Accelerator-Produced Radioactive Materi-

als (NORM/NARM). Naturally occurring radioactive material and accel-
erator-produced radioactive material lie outside NRC's regulatory
authority and are subject to health and safety regulation by the states and
other Federal agencies. 18 The waste is generally subclassified as diffuse
(< 2 nCi/g 226 Ra or equivalent) or discrete (> 2 nCi/g 226 Ra or
equivalent). 19 They are under review by EPA and may be regulated under
TSCA or RCRA. 20

The above categories, defined according to relevant statutes and regulations, are
not the only classification scheme used to specify radioactive wastes. There are a
variety of purposes for different systems.

3.3.1.3 LLW Waste Subclassification

As for LLW subclassification, NRC has developed a scheme that is implemented
by 10 CFR 61. LLW is divided into two broad categories: waste that qualifies for
near-surface burial, and waste that requires deeper disposal (greater than Class C
LLW, or greater confinement waste). LLW that is regulated by the NRC and qualifies
for near-surface burial is separated into three classes. Subclasses of LLW can be
listed as follows:

• Class A. Class A waste is waste that is usually segregated from other

waste classes at the disposal site. They have low levels of radiation and
heat.

• Class B. Class B waste is waste that must meet more rigorous require-

ments on waste form to ensure stability after disposal. The waste has
higher concentrations of radioactivity than Class A and requires greater
isolation and packaging (and shielding for operations) than Class A waste.

• Class C. Class C waste is waste that not only must meet more rigorous

requirements on waste form to ensure stability, but also requires additional
measures at the disposal facility to protect against inattentive invasion. It
requires isolation from the biosphere for 500 years and must be buried at
least 5 m below the ground surface and must have an engineered barrier
(container and grouting).

• Greater than Class C. Greater than Class C waste is the waste that is

not generally allowable for near-ground surface disposal, and is the waste
for which form and disposal methods must be different, and in general
more stringent, than those specified for Class C waste. This is the LLW
that does not qualify for near-surface burial. This includes commercial
transuranics that have half-lives greater than 5 years and activity greater
than 100 nCi/g.