Low-level Radioactive Waste Disposal Research Articles

Disposal of low-level radioactive waste. Impact on the medical profession

During 1985, low-level radioactive waste disposal has become a critical concern. The issue has been forced by the threatened closure of the three commercial disposal sites. The medical community has used radioactive isotopes for decades in nuclear medicine, radiation therapy, radioimmunoassay, and biomedical research. Loss of disposal capacity for radioactive wastes generated by these activities, by the suppliers of radioisotopes, and by pharmaceutical companies will have a profound impact on the medical profession. (<i>JAMA</i>1985;254:2449-2451)

Disposal of Low-Level Radioactive Waste

During 1985, low-level radioactive waste disposal has become a critical concern. The issue has been forced by the threatened closure of the three commercial disposal sites. The medical community has used radioactive isotopes for decades in nuclear medicine, radiation therapy, radioimmunoassay, and biomedical research. Loss of disposal capacity for radioactive wastes generated by these activities, by the suppliers of radioisotopes, and by pharmaceutical companies will have a profound impact on the medical profession.

Estimate of dispersion in an unsaturated aquifer

The Nuclear Development Corporation of South Africa (Pty) Ltd. (NUCOR) is constructing a low-level radioactive waste disposal site near Springbok in Namaqualand, an arid region to the west of South Africa. A groundwater model was developed which required site-specific data and this work describes procedures developed to assess the dispersivity of the soil in the vicinity of the proposed site. Preliminary laboratory tests, carried out using a sodium chloride solution, indicated the order of magnitude of the dispersivity for saturated soil at various levels. This enabled site tests to be designed. The site tests were done by injecting a pulse of scandium-46 into a hole and monitoring the displacement of the radioactive cloud as it moved down under gravity and spread laterally. A mathematical model was developed to predict the behaviour of the cloud and calibration of the model yielded vertical and horizontal dispersivities. The dispersion of radioactivity at the cloud front was assumed to occur in unsaturated medium while the continuously injected water behind the radioactivity was assumed to disperse in a saturated medium. Thus monitoring the concentration of both yielded approximate values for the effective dispersivities in unsaturated and saturated media.

Geomorphology of the Western Bushmanland Plateau, Namaqualand, South Africa

Abstract Results of a geomorphic investigation at and around a proposed low and intermediate level radioactive waste disposal site on the western portion of the Bushmanland Plateau are reported. This plateau reflects a more intricate geomorphic history than simple erosion surface development. A complex sequence of erosional and aggradational phases, which is evident in the geomorphic record, has been established through analysis of surficial deposits, and consideration of evidence provided by palaeontological and palynological work, by radiometric dating of intrusives, and by interpretation of palaeodrainage patterns. Following planation in late Cretaceous and early Tertiary times, marginal uplift of the continent in the Oligocene promoted fan accumulation on the planed surface. Fan sediments were subsequently regraded contemporaneously with Miocene incision into the plateau surface following redirection of drainage in the Orange River system. The area has been covered by extensive dune fields since the M...

The Great State of Uncertainty In Low-Level Waste Disposal

Faced with a 1986 deadline for completing their low-level radioactive waste disposal plans, individual states are forming regional compacts to share responsibility. Four compacts involving 24 states are ready for Congressional approval, while the other compacts have yet to receive state ratification. Five states have not yet arranged interstate alignment, and their plans for low-level waste disposal remain uncertain. Texas chose to act alone, and has begun a site selection process. Utilities are not actively involved in the compact negotiations or the site selection process, although the outcome will directly affect future disposal costs and related technological choices. The options for volume reduction include evaporation, supercompaction and incineration. A computer code (VRTECH) analyzes technologies and economic factors for utilities. 5 references, 5 figures.

Biotic transport of radionuclides from a low-level radioactive waste site.

In the United States, concern for human exposures to radioactivity associated with the disposal of low-level radioactive waste has resulted in a series of regulatory guides, environmental assessments, management practices, and modeling tools. A large number of radionuclide transport processes and mechanisms that may contribute to human exposure have been modeled, using computer programs to make the required calculations. The objective of our work was to evaluate the relevance of potential biological transport processes in the assessment of potential impacts at low-level waste (LLW) disposal sites. As part of this effort, we developed an order-of-magnitude estimate for potential dose to man resulting from biological transport by burrowing animals and by plant translocation at a reference low-level waste site in the arid west. We also made comparative dose-to-man estimates for a more commonly considered human intrusion exposure scenario. Parameter values for defining a reference arid LLW disposal site and biotic transport processes are based on data reported in current literature. Estimates of waste volumes for the western United States are based on information described by the U.S. Nuclear Regulatory Commission in the Draft Environmental Impact Statement in support of 10 CFR Part 61. Our estimates of the dose-to-man resulting from biotic transport are of the same order of magnitude as those resulting from a more commonly evaluated human intrusion scenario. The previously assumed lack of potential importance of biotic transport at LLW sites in earlier assessment studies is not confirmed by our findings. Our results indicate that long-term biological transport processes have the potential to influence LLW site performance, and should be carefully evaluated as part of the impact assessment process.

Interstate Compacts and the Management of Low Level Radioactive Wastes

The resurgence of the states as political actors within the context of American federalism has been a phenomenon attracting notice from myriad quarters over the past several years. Constitutional and statutory reforms have strengthened the powers of the governors, streamlined the executive branches, made state legislatures more effective, efficient, accountable, and responsive, and modernized judicial systems.' The education, experience, and professionalism of elected, appointed, and civil service employees in state government have improved considerably in recent years.2 The states' capacity to act has been enhanced, accompanied and followed by increased innovative behavior in various policy fields. As the states have sought to shed their image as the weak link in the American intergovernmental network, the national government under the philosophy of New Federalism has begun a gradual withdrawal from policy initiative, looking increasingly to the states as policy innovators and administrators. The general trend in American federalism seems to be in the direction of the decentralization of responsibility for programs and program funding from the national government to the states. It has not been a smooth transition, as increasing conflicts between the states and Washington indicate.3 The gears of American federalism have alternately slipped and held strong as new directions have been considered and embarked upon. The subject of this article is a vehicle which shows unusual promise for resolving nationalstate and interstate conflicts and problems during this uncertain period in intergovernmental relations-the interstate compact-and one of the most recent applications of this device among the states-the development of compacts for the management and disposal of lowlevel radioactive wastes. After many years of little public attention, the management and disposal of low-level radioactive wastes (LLW) became a subject of intense scrutiny during the late 1970s. Three disposal facilities were closed down while the states hosting the three remaining burial sites began to resist their role as nuclear waste garbage dumps. The proposed solution that emerged from a year or so of subsequent federal-state conflict was legislation which encouraged state assumption of the responsibility for LLW through the formation of interstate compacts. Interstate compacts for the regional disposal of LLW appeared to offer benefits both to the national government and to the states. The national government finally would be able to rid itself of day-to-day responsibility for the increasingly contentious problem of LLW management. The states would be able to exercise their historical constitutional authority over land use and the protection of the public health and safety. Interstate compacts for LLW represent an important test of the vitality of the states and their ability to solve mutual problems in a collective fashion. Following a discussion of the history, process, and uses of interstate compacts generally, we will describe and analyze the development and progress of interstate compacting for LLW.

Community Response to Low-Level Radioactive Waste: A Case Study of an Attempt to Establish a Waste Reduction and Incineration Facility

The Federal Low-Level Radioactive Waste Policy Act of 1980 specified a 1986 deadline for the establishment of state and regional low-level radioactive waste disposal sites. There is little optimism that the deadline will be met. Morris K. Udall has introduced Bill HR 1083 in Congress which proposes extending the deadline to 1993 and specifying a 40 percent reduction in the volume of wastes shipped. Waste volume can be reduced through incineration and compaction technologies. However, it may be as difficult to convince communities that a waste treatment facility is a good investment as it is to convince them that a disposal site is worth having. In other words, the waste volume reduction argument may ultimately depend on cutbacks in the nuclear industry. This research reports one community's response to the possibility of a low-level radioactive waste compaction and incineration facility. The case is especially interesting because the community needs new industries and has a history of living with a nuclear materials facility. In spite of that the community's response was quite negative, fueled by a vocal local opposition group and anti-nuclear activists. Survey data indicates that despite general opposition people still feel the need for more information on radioactive materials and are willing to attend education sessions if the time and place are convenient. Suggestions are given for those considering future attempts to establish low-level radioactive waste reduction facilities.

Low-level Radioactive Waste Disposal: How Are States Setting Their Sites?

Low-level Radioactive Waste Disposal: How Are States Setting Their Sites?

Geohydrology of Industrial Waste Disposal Site

An existing desert site for hazardous chemical and low-level radioactive waste disposal is evaluated for suitability. This site is characterized using geologic, geohydrologic, geochemical, and other considerations. Design and operation of the disposal facility is considered. Site characteristics are also evaluated with respect to new and proposed regulatory requirements under the Resource Conservation and Recovery Act (1976) regulations, 40 CFR Part 264, and the ''Licensing Requirements for Landfill Disposal of Radioactive Waste,'' 10 CRF Part 61. The advantages and disadvantages of siting new disposal facilities in similar desert areas are reviewed and contrasted to siting in humid locations.

Physical Properties of Saltstone: Physical Properties of Saltstone: A Savannah River Plant Waste Form

AbstractA cement-based waste form, “saltstone,” has been designed for disposal of Savannah River Plant low-level radioactive salt waste. Laboratory and field tests indicate that this stabilization process greatly reduces the mobility of all of the waste constituents in the surface and near-surface environment. Bulk properties of this material have been tailored with respect to salt leach rate, permeability, and compressive strength. Microstructure and mineralogy were characterized by SEM and x-ray diffraction analyses.Compressive strength was found to increase as the water to cement ratio decreased. Porosity and mean pore size increased with increasing water to cement ratios. Bulk diffusivities of the various ions dissolved in the pore solutions were also found to increase as water to cement ratios increased.

Source Term Development For Tritium at the Sheffield Disposal Site

AbstractThe Sheffield low-level radioactive waste disposal site, which ceased operation in 1978, has been the focus of modeling efforts by the NRC for the purpose of predicting long-term site behavior. To provide the NRC with information required for its modeling effort, a study to define the source term for tritium in eight trenches at the Sheffield site has been undertaken. Tritium is of special interest since significant concentrations of the isotope have been found in groundwater samples taken at the site and at locations outside the original site boundary. Previous estimates of tritium site inventory at Sheffield are in wide disagreement. In this study, the tritium inventory in the eight trenches was estimated by reviewing the radioactive shipping records (RSRs) for waste buried in these trenches. It has been found that the tritium shipped for burial at the site was probably higher than previously estimated. In the eight trenches surveyed, which amount to roughly one half the total volume and activity buried at Sheffield, approximately 2350 Ci of tritium from non-fuel cycle sources were identified.

Regional waste treatment with monolith disposal for low-level radioactive waste

An alternative system is proposed for the disposal of low-level radioactive waste. This system, called REgional Treatment with MOnolith Disposal (RETMOD), is based on integrating three commercial technologies: automated package warehousing, whole-barrel rotary kiln incineration, and cement-based grouts for radioactive waste disposal. In the simplified flowsheet, all the sludges, liquids, resins, and combustible wastes are transported to regional facilities where they are incinerated. The ash is then mixed with special cement-based grouts, and the resulting mixture is poured into trenches to form large waste-cement monoliths. Wastes that do not require treatment, such as damaged and discarded equipment, are prepositioned in the trenches with the waste-cement mixture poured on top. The RETMOD system may provide higher safety margins by conversion of wastes into a solidified low-leach form, creation of low-surface area waste-cement monoliths, and centralization of waste processing into a few specialized facilities. Institutional problems would be simplified by placing total responsibility for safe disposal on the disposal site operator. Lower costs may be realized through reduced handling costs, the economics of scale, simplified operations, and less restrictive waste packaging requirements.

Cement-Based Waste forms for Disposal of Savannah River Plant Low-Level Radioactive Salt Waste

ABSTRACTDefense waste processing at the Savannah River Plant will include decontamination and disposal of approximately 100 million liters of soluble salts containing primarily NaNO3, NaOH, NaNO2, NaAl(OH)4, and Na2SO4. A cement-based waste form, “saltstone,” has been designed for disposal of Savannah River Plant low-level radioactive salt waste. Bulk properties of this material have been tailored with respect to salt leach rate, permeability, and compressive strength. Microstructure and mineralogy of leached and unleached specimens were characterized by SEM and X-ray diffraction analyses, respectively. It has been concluded that the salt leach rate can be limited so that amounts of salt and radionuclides in the groundwater at the perimeter of the 100 acre disposal site will not exceed EPA drinking water standards.

Hydrologic factors and90Sr transport: A case study

Lack of runoff control is probably the most important potential source of problems in the operation of solid, low-level radioactive waste disposal areas. Solid waste disposal area (SWDA) 4 at Oak Ridge National Laboratory is an example of the combined effects of hydrologic factors and burial ground operations on radionuclide transport. Results from a study of90Sr transport at SWDA 4 show that both surface water and groundwater flows are important runoff control considerations and may vary in relative importance over an extended period of time. For the area studied, it is currently estimated that at least 80% of the90Sr transport is directly related to surface runoff. Therefore, it is concluded that the key to remedial action at SWDA 4 is to control surface runoff.

Use of Poisoned Land/Inland Seas for Low Level Radioactive Waste Disposal

It is widely known that certain areas of the earth are characterized by such high concentrations of toxic elements that their use by plants or animals is precluded. A water hole whose water contains potentially toxic quantities of As is a common example of such a naturally poisoned area. The dry salt basins of the Basin and Range Province in Nevada and western Utah are largely relict inland salt seas and, because many of the salt basins have total interior drainage of both surface and ground water, these basins represent unique geochemical environments for the entrapment and concentration of mobile elements. Through leaching, transport, and ultimate deposition from throughout the water shed, the closed salt basins are hydrologic sinks in which toxic materials such as As, Sb, Hg, and other heavy metals become concentrated in a relatively confined area.

Trench Water Chemistry at Commercially Operated Low-Level Radioactive Waste Disposal Sites

ABSTRACTWater samples from the disposal trenches of two low-level radioactive waste burial sites were analyzed for their inorganic, organic, and radionuclide contents. Since oxidation of the trench waters can occur during their movement along the groundwater flow path,experiments were performed to measure the chemical and physical changes that occur in these waters upon oxidation. In addition to the highly acidic conditions of the oxidized Maxey Flats trench water, low concentrations of chelating agents, shown to exist in trench waters, may be responsible for keeping radionuclides in solution following oxidation of anoxic trench leachates from Maxey Flats and West Valley burial sites.

Low-Level Waste Disposal Analysis

ABSTRACTThe safety of low-level radioactive waste disposal sites is analyzed using the computer code LOTRAN. Radiation doses to off-site individuals and to future land reclaimers are computed for a generic disposal site located in a humid Eastern environment. The predicted doses are compared to illustrative performance criteria developed under this project. Results provide insight into those characteristics of low-level waste disposal systems most important to public safety and will allow analyses of tradeoffs among natural and engineered features.

Sorption measurements performed under site-specific conditions — maxey flats, Kentucky, and west valley, new york, disposal sites

Sorption coefficients have been determined using site-specific sediments and trench waters, collected from the Maxey Flats, Kentucky, and West Valley, New York, low-level radioactive waste disposal sites. Experimental apparatus and procedures are described to preserve the anoxic character of the liquid phases during experiments. Experiments using anoxic and oxidized trench waters were performed as functions of solution pH, soil/solution ratio, water and soil composition. The lowest sorption was observed with the combination of anoxic waters and untreated soil—the combination most closely resembling the immediate trench environment. For best results in predictive applications, sorption data should be determined under conditions which simulate those in the field as closely as possible. The total radionuclide retention capacity of reducing geochemical environments is the sum of sorption processes on solid phases, as well as precicipation, and coprecipitation reactions involving iron mineral phases (sulfides and oxyhydroxides).

Characterization of Organics in Leachates from Low-Level Radioactive Waste Disposal Sites

Several trench leachate samples collected from commercially operated low-level radioactive waste disposal sites at Maxey Flats, Kentucky and at West Valley, New York were analyzed for organic constituents. The organic compounds in the water samples were extracted with methylene chloride, separated into acidic, basic, and neutral fractions, and analyzed by gas chromatography and mass spectrometry. About 75 compounds consisting of several straight and branched chain aliphatic acids, aromatic acids, alcohols, aldehydes, ketones, amines, aromatic hydrocarbons, esters, ethers, and phenols were identified in the leachate samples. These compounds represent, in general, the synthetic and natural organic wastes such as contaminated cellulosic materials, scintillation liquids, solvents, and decontamination fluids buried in the trenches and their biological decomposition products. The organic compounds, especially the organic acids, phthalates, and tributyl phosphate, may influence the mobility of the radionuclides from the burial trenches by solubilization, leaching, and formation of weak complexes.