Radioactive Waste Management Site Research Articles

Management of radioactive waste from application of radioactive materials and small reactors in non-nuclear industries in Canada and the implications for their new application in the future

<abstract> <p>A large number of artificial-origin radionuclides from irradiation in small reactors and/or nuclear reactions in accelerators are currently used in non-nuclear industries such as education, oil and gas, consumer merchandise, research, and medicine. Radioactive wastes from the use of these radionuclides in non-nuclear industries include expired sealed radioactive sources, biological materials, radionuclide-containing chemicals, contaminated equipment, and very small quantities of used nuclear fuel. Although being less challenging and complex than nuclear energy production and research waste streams, these wastes are subject to the common nuclear regulations by the Canadian Nuclear Safety Commission, and are managed following domestic and international standards and guidelines made by the Canadian Standards Association, International Atomic Energy Agency, and International Organization for Standardization. Management practices used in the nuclear industry in Canada are commonly applied to the non-nuclear industry radioactive waste streams, such as waste handling, treatment, packaging, storage, transportation, clearance and exemptions, and disposal. The half-lives of radionuclides in non‑nuclear applications range from hours to thousands of years, and their activities in non-nuclear industrial applications can be as low as their clearance level or as high as the upper limits for intermediate level radioactive waste. Waste containing only short half-life radionuclides is placed in temporary storage to allow decay, and then is cleared and disposed of through non-radioactive waste routes. Non‑clearable waste materials are treated, consolidated, and managed along with radioactive waste generated from the nuclear industries at designated radioactive waste management sites.</p> </abstract>

Policy Network and the Role of Government: A Case of Selecting a Radioactive Waste Management Site in South Korea

Policy Network and the Role of Government: A Case of Selecting a Radioactive Waste Management Site in South Korea

Tributyl phosphate biodegradation to butanol and phosphate and utilization by a novel bacterial isolate, Sphingobium sp. strain RSMS

A Sphingobium sp. strain isolated from radioactive solid waste management site (RSMS) completely degraded 7.98g/L of tributyl phosphate (TBP) from TBP containing suspensions in 3days. It also completely degraded 20mM dibutyl phosphate (DBP) within 2days. The strain tolerated high levels of TBP and showed excellent stability with respect to TBP degradation over several repeated subcultures. On solid minimal media or Luria Bertani media supplemented with TBP, the RSMS strain showed a clear zone of TBP degradation around the colony. Gas chromatography and spectrophotometry analyses identified DBP as the intermediate and butanol and phosphate as the products of TBP biodegradation. The RSMS strain utilized both TBP and DBP as the sole source of carbon and phosphorous for its growth. The butanol released was completely utilized by the strain as a carbon source thereby leaving no toxic residue in the medium. Degradation of TBP or DBP was found to be suppressed by high concentration of glucose which also inhibited TBP or DBP dependent growth. The results highlight the potential of Sphingobium sp. strain RSMS for bioremediation of TBP and for further molecular investigation.

Multiphase, Multicomponent Parameter Estimation for Liquid and Vapor Fluxes in Deep Arid Systems Using Hydrologic Data and Natural Environmental Tracers

Multiphase, multicomponent numerical models of long‐term unsaturated‐zone liquid and vapor movement were created for a thick alluvial basin at the Nevada Test Site to predict present‐day liquid and vapor fluxes. The numerical models are based on recently developed conceptual models of unsaturated‐zone moisture movement in thick alluvium that explain present‐day water potential and tracer profiles in terms of major climate and vegetation transitions that have occurred during the past 10 000 yr or more. The numerical models were calibrated using borehole hydrologic and environmental tracer data available from a low‐level radioactive waste management site located in a former nuclear weapons testing area. The environmental tracer data used in the model calibration includes tracers that migrate in both the liquid and vapor phases (δD, δ18O) and tracers that migrate solely as dissolved solutes (Cl), thus enabling the estimation of some gas‐phase as well as liquid‐phase transport parameters. Parameter uncertainties and correlations identified during model calibration were used to generate parameter combinations for a set of Monte Carlo simulations to more fully characterize the uncertainty in liquid and vapor fluxes. The calculated background liquid and vapor fluxes decrease as the estimated time since the transition to the present‐day arid climate increases. However, on the whole, the estimated fluxes display relatively little variability because correlations among parameters tend to create parameter sets for which changes in some parameters offset the effects of others in the set. Independent estimates on the timing since the climate transition established from packrat midden data were essential for constraining the model calibration results. The study demonstrates the utility of environmental tracer data in developing numerical models of liquid‐ and gas‐phase moisture movement and the importance of considering parameter correlations when using Monte Carlo analysis to characterize the uncertainty in moisture fluxes.

SERENDIPITY: CAPTURING A DESIGN LEVEL PRECIPITATION EVENT1

ABSTRACT: On February 23–24, 1998, a frontal system moved across the U.S. Department of Energy's 3,500 km2 Nevada Test Site (NTS) and resulted in significant depths of precipitation at all recording gages on the NTS. A preliminary analysis suggested that this precipitation event was of the magnitude and duration for which many flood mitigation structures have been designed. Given the data and field observations available and the potential implications of the event on the methodologies used to size flood mitigation structures throughout the West, a detailed analysis of this event was undertaken. The goals of this study were to compare this event with the regulatory design precipitation event, compare the estimated peak flow rates from the rainfall/runoff model used to size the flood mitigation structures at a radioactive waste management site with the estimated peak flows from the precipitation event, and examine if modification of the standard source of the design depths of precipitation is warranted.

Evaluation of uranium and arsenic retention by soil from a low level radioactive waste management site using sequential extraction

The European Communities Bureau of Reference (BCR) and Chunguo sequential extraction procedures were employed to evaluate the retention of U and As by a soil contaminated with low level radioactive waste. Modifications were made to both procedures to optimize the measurement of soil and extractant samples using epithermal neutron activation analysis. Based on the BCR procedure, approximately 20% of the U appeared to be bound to the carbonate fraction, 10% to the mineral oxide fraction and 20% to the organic fraction. In the case of As, the majority was strongly bound in the residue fraction. The results obtained with the Chunguo procedure supported these conclusions to some extent, in that the majority of the U and As was found to be strongly bound to the soil in a manner consistent with its presence in the residue fraction.

Wavelet analysis of multiscale permeabilities in the subsurface

Wavelet analysis is a new mathematical theory and calculation method for separating and sorting structures on different time scales at different times, and on different spatial scales at different locations. This method has been used to identify spatial heterogeneity of geologic structures and to estimate spatial scales of geophysical parameters in the subsurface. We used the integral wavelet transform to analyze the spatial variability of permeability in the alluvial fan deposits in Radioactive Waste Management Site Area 5 of Nevada. The mother wavelet which we used is the “Mexican Hat” function. A wavelet variance is defined to detect the characteristic scales of non‐periodically spaced spatial structures. Results showed heterogeneity of spatial structure in permeability at hierarchical scales and difference of scales between transects in spatially distributed permeability. These multiscale features of spatial variability of permeability provide an explanation for the strong quasi‐periodic behavior in the horizontal and vertical semivariograms. A comparison among wavelets, fractals, and traditional geostatistics is also given.

West Valley Plutonium and Americium-241 in Lake Ontario sediments off the mouth of Niagara River

Recently deposited fine-grained sediments in Lake Ontario off the mouth of Niagara River contain highly toxic238Pu,239,240pu, and241Pu (241Am) from global fallout as well as from low level releases of these radionuclides from the West Valley radioactive waste management site. This is demonstrated through sediment core radionuclide inventories, radionuclide activity ratios, and assignment of independently-derived210Pb dates to sediment core segments. Reasonable agreement between measured and calculated inventories, derived using various assumptions and available discharge and environmental monitoring data, suggests that nearly all of the West Valley-delivered239,240Pu and 24241Am resides in the bottom sediments of Lake Ontario, comprising about 36 and 80%, respectively, of the measured (1982) inventories of these radionuclides. The West Valley241Am is largely derived from the decay of241Pu and, assuming negligible further deliveries of241pu (241Am), its growth is expected to continue until about 2040.

Investigation of Lake Ontario water quality near Port Granby radioactive waste management site

The concentrations of226Ra, As, and NO 3 − have been measured in Lake Ontario waters off Eldorado Nuclear Limited's Port Granby radioactive waste management site. Only one sample gave a226Ra value higher than the Ontario criterion for public surface water supplies. The highest levels of As and NO 3 − were below the Ontario criteria. The leachate plume appears to move parallel to the shoreline in the direction of the prevailing wind but disperses rapidly reaching ambient levels within 150 m of the source. The leaching of these pollutants has only a minor effect on the lake water quality.

Hydrogeologic Investigation of a Radioactive Waste Management Site in Southern Alberta

For the past 2 years, detailed field and laboratory studies have focused on the hydrogeologic investigation of a proposed, subsurface, radioactive waste management site in Alberta at the Defence Research Establishment Suffield. The basic approach has involved test drilling and sampling augmented by down-hole geophysical techniques to establish stratigraphic sequences. In addition, piezometers and soil moisture – temperature blocks have been emplaced to define the saturated–unsaturated flow regime. Laboratory studies of drift and bedrock samples have characterized variations in mineralogy, texture, and sorptive properties.Piezometric data indicate that the site is predominantly a recharge area with median values of permeability ranging from 2.8 × 10−2 to 2.8 × 10−4 ft/day (1 × 10−5 to 1 × 10−7 cm/s). To reach the zone of saturation, recharge water must pass downward through a maximum of 120 ft (36.3 m) of unsaturated, glacial drift with cation exchange capacities ranging from 25 to 105 mequiv per 100 g. The absence of water level fluctuations in observation wells and the soil moisture block data indicate that the quantity of water moving downward through the waste management site is small.

Hydrogeologic Investigation of a Radioactive Waste Management Site in Southern Alberta: Reply

For the past 2 years, detailed field and laboratory studies have focused on the hydrogeologic investigation of a proposed, subsurface, radioactive waste management site in Alberta at the Defence Research Establishment Suffield. The basic approach has involved test drilling and sampling augmented by down-hole geophysical techniques to establish stratigraphic sequences. In addition, piezometers and soil moisture – temperature blocks have been emplaced to define the saturated–unsaturated flow regime. Laboratory studies of drift and bedrock samples have characterized variations in mineralogy, texture, and sorptive properties.Piezometric data indicate that the site is predominantly a recharge area with median values of permeability ranging from 2.8 × 10−2 to 2.8 × 10−4 ft/day (1 × 10−5 to 1 × 10−7 cm/s). To reach the zone of saturation, recharge water must pass downward through a maximum of 120 ft (36.3 m) of unsaturated, glacial drift with cation exchange capacities ranging from 25 to 105 mequiv per 100 g. Th...

Hydrogeologic investigation of a radioactive waste management site in Southern Alberta : Conference. Preprint. 6F, 3T, 8R. PROC. 27TH CANADIAN GEOTECHNICAL CONF. EDMONTON, NOV. 1974, P17–23

Hydrogeologic investigation of a radioactive waste management site in Southern Alberta : Conference. Preprint. 6F, 3T, 8R. PROC. 27TH CANADIAN GEOTECHNICAL CONF. EDMONTON, NOV. 1974, P17–23