Mixed Low-level Radioactive Waste Research Articles

Suspensions of fluor-containing nanoparticles for quantifying β−-emitting radionuclides in non-hazardous media

Nanoparticles containing scintillants were prepared from oil-in-water microemulsions in which styrene-divinylbenzene comprised the oil phase. Primary and secondary fluors [2,5-diphenyloxazole and 1,4-bis(2-methylstyryl) benzene] were dissolved in the oil phase, which was emulsified with dodecyl trimethylammonium bromide or sodium dodecyl sulfate before polymerization by the addition of sodium persulfate. The resulting suspension qualified as non-hazardous waste by testing against US EPA standards for reactivity, pH, ignitability, and toxicity characteristic leaching.14C-glycerol was added to the aqueous nanoparticle suspension and to a conventional organic scintillation cocktail, and the relative efficiency of detection was obtained by liquid scintillation counting. The results were compared with a mathematical model that predicted the effect of particle size and concentration on the probability of an emitted β− particle interacting with a suspended particle. The use of these nanoparticle suspensions represents an opportunity to reduce mixed low-level radioactive hazardous waste generated by liquid scintillation counting.

7.1.3 Radioactive Material Transportation Requirements for the Department of Energy

AbstractThe Department of Energy (DOE) created the National Transportation Program (NTP) whose goal is to ensure the availability of safe, efficient, and timely transportation of DOE materials. The Integration and Planning Group of the NTP, assisted by Global Technologies Incorporated (GTI), was tasked to identify requirements associated with the transport of DOE Environmental Management (EM) radiological waste/material. A systems engineering approach was used to identify source documents, extract requirements, perform a functional analysis, and set up a transportation requirements management database in RDD‐100. Functions and requirements for transporting the following DOE radioactive waste/material are contained in the database: high level radioactive waste (HLW), low‐level radioactive waste (LLW), mixed low‐level radioactive waste (MLLW), nuclear materials (NM), spent nuclear fuel (SNF), and transuranic waste (TRU waste). The requirements will be used in the development of standard transportation protocols for DOE shipping. The protocols will then be combined into a DOE Transportation Program Management Guide, which will be used to standardize DOE transportation processes.

Performance Analysis for Disposal of Mixed Low-Level Waste. I: Methodology

A simple methodology has been developed for evaluating the technical capabilities of potential sites for disposal of mixed low-level radioactive waste. The results of the evaluation are expressed as “permissible radionuclide concentrations in disposed waste.” The methodology includes an analysis of three separate pathways: (1) releases of radionuclides to groundwater; (2) releases of potentially volatile radionuclides to the atmosphere; and (3) the consequences of inadvertent intrusion into a disposal facility. For each radionuclide, its limiting permissible concentration in disposed waste is the lowest of the permissible concentrations determined from each of the three pathways. These permissible concentrations in waste at an evaluated site can be used to assess the capability of the site to dispose of waste streams containing multiple radionuclides.

Performance Analysis for Disposal of Mixed Low-Level Waste. II: Results

Ten sites were evaluated as potential locations for disposal of mixed low-level radioactive waste using a simple methodology. Three environmental pathways (water, atmospheric, and inadvertent intruder) were analyzed using generic transport models that were modified for site-specific conditions. The results were summarized by grouping the 58 evaluated radionuclides according to their half-lives and environmental mobility and by their limiting pathway (i.e., the pathway providing the lowest permissible radionuclide concentration in disposed waste of the three evaluated pathways). The results indicate that all evaluated sites have the technical capability for disposal of some radionuclides in the waste. For most radionuclides, the intruder scenarios were more important in determining permissible radionuclide concentrations than the other pathways, particularly for arid sites. For humid sites, if the water pathway is not the most limiting and the permissible radionuclide concentration is high, a more sophisticated and rigorous analysis of the water pathway may not be warranted. However, if the permissible concentration is relatively low, more refined analyses may produce higher permissible concentrations based on additional site characterization data.

Managing mixed low-level radioactive waste

Managing mixed low-level radioactive waste