INCINERATION OF LOW-LEVEL RADIOACTIVE WASTES-
A PLANNING APPROACH
Freeman C. Cook, Jr., Environmental Engineer
Reid, Quebe, Allison, Wilcox & Associates, Inc.
Indianapolis, Indiana 46254
Mack L. Richard, Radiation Safety Officer
Indiana University Medical Center
Indianapolis, Indiana 46223
BACKGROUND
Low-level radioactive wastes (radwastes; LLRW) are ordinary waste forms which have become
contaminated with small quantities of radioactivity. Institutional low-level radwastes are non-fuel
cycle wastes which are generated from biomedical research activities and the practice of nuclear
medicine. Medical schools, research institutions and hospitals are responsible for a significant fraction of the total volume of low-level wastes disposed of annually [1]. Hydrogen-3 (tritium) and
carbon-14 are the isotopes most commonly found in institutional LLRW. These nuclides are naturally-occurring and ubiquitous in the environment and pose a minimal exposure hazard at the
concentrations normally present in low-level wastes.
Low-level radwastes from all sources have traditionally been shipped to land disposal sites for
shallow land burial. However, only three commercial land depositories remain in operation today,
and burial space is now considered a scarce resource. As a result, transport and disposal costs associated with shallow land burial have escalated sharply.
The Low-Level Waste Institutional Incinerator Program was initiated in 1979 in order to assess the
feasibility of LLRW incineration [2]. In conjunction with this and the National Low-Level Waste
Management Program, the Department of Energy (DOE) has sponsored incinerator research and
development at several laboratories and has funded demonstration incinerator projects at Purdue
University and the University of Maryland at Baltimore [3,4]. This research has demonstrated the
efficacy of incineration as a management technique for LLRW volume reduction [5]. Broad application of this technology would potentially prolong the useful lives of the commercial burial sites and
effect reductions in generator transport and disposal costs.
REGULATORY CONSIDERATIONS
The Nuclear Regulatory Commission (NRC) has established maximum permissible concentrations
(MPCs) for the release of radioactivity into air, water, and soil [6]. NRC licensees are required to
comply with these limits in the disposal of low-level radwastes.
The NRC, in recognition of the burial site limitations, has exempted certain previously regulated
low-level wastes from its control. Liquid scintillation counting fluids (LSCF) used in tracer studies
and animal carcasses containing less than 0.05 microcuries t>Ci) of hydrogen-3 (H-3) or carbon-14
(C-14) per gram of substance may now be disposed of without regard to radioactivity [6]. Exempt
LSCF wastes containing toluene, xylene, or other organic solvents are candidates for incineration [7].
These low-level wastes are hazardous wastes under the Resource Conservation and Recovery Act
(RCRA) definition due to their chemical properties and are, therefore, subject to regulation by EPA
and the Indiana State Environmental Management Board. Also, exempt radwastes are considered
"special wastes" under state law and, as such, require agency approval for disposal.
Emissions produced by a low-level waste incinerator are required to meet all appropriate air
quality standards. Radiation dose assessments must be performed to determine the dose potential
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