Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 53 for “"actinides"”.
-
Separation and Coordination Chemistry of Actinides
… at ORNL which aimed to separate transuranium actinides from on-site bulk lanthanide waste. The molecule in question had comparable separation capabilities to a reference molecule and was robust toward varying extraction conditions. Unfortunately, the kinetics were slow enough to render it less …
-
Criticality and thermal analyses of separated actinides in transmutation
… Once separated from the other minor actinides, the isotopes can lead to nuclear fission with the subsequent release of a large amount of radiation. A neutron criticality code was used to determine the effective neutron multiplication factor for varying quantities of curium and …
-
Fertile free fuels for plutonium and minor actinides burning in LWRs
… CERMET. The fuel may consist of plutonium, minor actinides (MA), or both which are termed trans-uranium (TRU) fuel. The transmutation rate and the transmuted fraction of initial loadings are calculated using CASMO-4. Different inert matrix fuels have similar burning abilities in terms of how much …
-
1,2–Dithiolate Complexes of the Lanthanides and Actinides and High– Pressure Studies of f–Element Complexes
… in bonding, that soft donor ligands and lighter actinides result in a greater degree of f–orbital involvement. It also reveals the importance of redox chemistry in pressure effects of the spectra as in the case of berkelium, which having an accessible +4–oxidation state, exhibits much smaller …
-
Development of a separations procedure for plutonium and uranium utilizing branched diglycolamide resin
… better understand the sorption behavior of these actinides with the resin with varying concentrations of iron, as well as in different acidities. These batch sorption experiments described the distribution coefficients for these actinides in different acids, which were useful in determining the …
-
Advancing solvent extraction technology for improved management of contaminated liquors
The separation of minor actinides (An) such as americium and curium (Am, Cm) from lanthanides (Ln) in spent nuclear fuel can reduce the radiotoxicity of the eventual waste product as well as the required size and environmental impact of any subsequent geological disposal. In addition, separation of …
-
The Effect of Microwave Energy on Sintering
… reactors; SNF consists of long-lived radioactive actinides which have an average half-life of several thousand years (e.g. Plutonium-239 with a half-life of 24,000 years, and Americium-243 with a half-life of 7,360 years). Several multinational organizations are making an attempt to extract the …
-
Chromatographic Separation of Metals
… from the fission products and other minor actinides produced during the fuel use. The uranium and plutonium constitutes approximately 96 % by mass of the irradiated fuel and for this to be removed, requires large volumes of extractant and equipment with large surface area contactors and …
-
X-ray absorption spectroscopy of actinide speciation in solid solutions
It is widely recognized that the behavior of actinides in the environment is dictated by their speciation, or chemical form. It is therefore imperative to have a clear understanding of a waste form or environmental contaminant in order to effectively assess and treat the affected area. Current …
-
Optimization of actinide transmutation in innovative lead-cooled fast reactors
… as efficient incinerators of plutonium and minor actinides (MAs) for application to dedicated fuel cycles for transmutation. A methodology is developed that assesses the actinide incineration performance of several transmutation fuel cycles, both single and multi-tiered, on the basis of …
-
Rethinking the light water reactor fuel cycle
… of years. In addition, plutonium and other actinides, after the decay of fission products, could become targets for weapon proliferators. Furthermore, only a small fraction of the energy potential in the fuel is being used. All these concerns can be addressed if a closed fuel cycle strategy …
-
Radionuclide dose assessment of groundwater migrating from the Benham Events, Nts: A solute flux approach
… near-cavity chemistry (e.g. solubility of actinides), conservative assumptions were used to estimate a hydrologic source term. By using a two-dimensional stochastic groundwater contaminant transport code, radionuclide transport was modeled from the Benham event to control planes 10, 20, and …
-
Actinide minimization using pressurized water reactors
Transuranic actinides dominate the long-term radiotoxity in spent LWR fuel. In an open fuel cycle, they impose a long-term burden on geologic repositories. Transmuting these materials in reactor systems is one way to ease the long-term burden on the repository. Examining the maximum possible …
-
Crystal engineering of novel organic-inorganic compounds of N- and O-donor dipyridyl ligands
… were investigated. These include compounds of actinides, lanthanides, transition and main group metals using dipyridyl ligands (4,4'-bipyridine-N,N'-dioxide (bpdo), 1,2-bis(4-pyridyl)ethane (BPE) and 1,2-di(4-pyridyl)ethylene (OPE) Compounds prepared were characterised by x-ray diffractometry. …
-
Multiphysics modeling, study, and analysis of atmospheric pressure plasma-based mass separation system for high-level radioactive waste treatment
… products with 80–160 amu, and 0.4% is for actinides with 225–250 amu. Of this waste, 99.7% of the radioactivity comes from the fission products, while substantial bulk elements contribute only 0.1% of the radioactivity. Therefore, clean separation as a group of elements may significantly …
-
The sorption of uranium(VI) and neptunium(V) onto surfaces of selected metal oxides and alumosilicates studied by in situ vibrational spectroscopy
The migration behavior of actinides and other radioactive contaminants in the environment is controlled by prominent molecular phenomena such as hydrolysis and complexation reactions in aqueous solutions as well as the diffusion and sorption onto minerals present along groundwater flow paths. These …
-
Determination of actinide elements in environmental samples by ICP-MS
… it unsuitable for the determination of the actinides in soil and sediment samples. Subsequently, a polystyrene substrate which was dynamically coated with dipicolinic acid was used for HPLC coupled with SF-ICP-MS. Using this column it was possible to separate the various actinides from each …
-
Analysis of surrogate post-detonation urban debris (SPUD) gamma rays and self-attenuation
… the post-detonation fallout debris that includes actinides, urban materials, fission products, and activation products. The National Institute of Standards in Technology (NIST) in concert with partner labs (Federal Bureau of Investigation (FBI) and National Physics Laboratory (NPL)) and with …
-
Transuranic Imidophosphorane Chemistry
… we present the expansion of this work to the actinides to study the molecular and electronic structures of transuranic imidophosphorane compounds. The isolation, characterization, and redox chemistry of a large isostructural family of Ce, U, Np, and Pu complexes is presented. These compounds …
Page 1 of 3