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.
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Showing 1 to 16 of 16 for “"Americium"”.
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Criticality and thermal analyses of separated actinides in transmutation
Curium and americium pose special problems in the chemical preparation of spent nuclear fuel for 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 …
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Facility-Specific Radiation Exposure Risks and Their Implications for Radiation Workers at Department of Energy Laboratories
… to assess the risks to workers engaged in americium recovery operations at Los Alamos National Laboratory. The work described in Chapter 3 develops a full radiological protection assessment for the new americium recovery project, including development of exposure cases, creation and …
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Feasibility Study of Minor Actinide Transmutation In Light-Water Reactors With Various Am/Cm Separation Efficiencies
… of this study was to examine the feasibility of americium transmutation in a typical light water reactor. Due to similar chemical properties of americium and curium and the difficulty associated with their chemical separation, the separation efficiency of these two elements was also considered. …
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Characterization of water-based liquid scintillator response to gammas and neutrons at varying scintillator-surfactant concentrations
… to Sodium-22 (²²Na) 511 keV gamma source and Americium-24 Beryllium (AmBe) 2-10 MeV neutron source is explored by taking pulse area spectra data at scintillator-surfactant concentrations of 0.5%, 1.0% and 2.0%. An analysis of light yield reveals an increasing linear correlation between …
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Imaging the ionization track of alpha recoils for the directional detection of weapons grade plutonium
… characterization testing using a low intensity Americium-Beryllium neutron source, compared with probability-based rate calculations and Geant4 simulation rates. The detector, in its current configuration agrees well with the expected rates, showing a 95% track reconstruction efficiency, …
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The Effect of Microwave Energy on Sintering
… 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 energetic value out of these nuclear stockpiles in order to minimize the risk of nuclear proliferation and reduce waste volume. …
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Investigation of the bubble detector response to high LET space radiation
… bubble detectors is established using a known Americium Beryllium(AmBe) neutron field. However, the space neutron field is considerably different from the AmBe field. Current models assume that bubbles are formed as a result of radiation interactions above a certain minimum LET threshold and …
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Characterization of Radiation Fields and Dose Assessment From Fuels Manufacturing For Advanced Fuel Cycles
… impact of varying the separation efficiency of americium (Am) and curium (Cm) was examined because separation steps in reprocessing and recycling do not allow for the complete separation of Am from Cm. The additional Cm will cause a sufficient increase in the neutron source term. The sensitivity …
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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 …
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Technical basis for use of a correlated neutron source in the uranium neutron coincidence collar
… collar (UNCL), which uses neutrons from an americium lithium (241AmLi) source to interrogate the assemblies from one side. Eighteen 3He tubes on the other three sides are used to count the coincidence neutrons from the induced fission reactions. Experiments have shown that 252Cf could also …
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Characterization of the Neutron Irradiation System for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories
… the neutron irradiation system consisting of americium 241 beryllium (241AmBe) neutron sources placed in a polyethylene shielding for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three …
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1,2–Dithiolate Complexes of the Lanthanides and Actinides and High– Pressure Studies of f–Element Complexes
… then examine complexes of neptunium, plutonium, americium, curium, and californium with the 1,2–dithiolate ligand maleonitrile dithiolate (mnt), which is a soft sulfur–donor ligand, contrasting with the hard oxygen–donor mellitate ligand from chapter 3. Spectroscopic, crystallographic, and …
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Determination of actinide elements in environmental samples by ICP-MS
… actinide elements neptunium, plutonium and americium, resulted in the successful determination of 239Pu and 237Np in biological reference materials. Detection limits were 700, 850, and 600 attograms (ag) for 237Np, 233Pu, and 241Am, respectively, for a 0.5 ml sample injection, and better …
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Chromatographic Separation of Metals
… gamma rays. Minor actinides such as neptunium, americium, curium, berkelium, californium, einsteinium, and fermium are the actinide elements in irradiated nuclear fuel other than uranium and plutonium; they are minor as they represent a very small proportion of actinides in comparison to U and …
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Decontamination method comparison testing using simulated contamination
… that exhibit a pH dependent speciation, such as americium or cobalt, can demonstrate radionuclide / material substrate specific chemistry that results in contaminant precipitation at the substrate surface, especially if the material has an intrinsically alkaline surface pH. For example, in the …
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Management of the UK plutonium stockpile using thorium fuelled Light Water Reactors
… feasibility of this approach. The build-up of americium-241 from decay of Pu-241 leads to increased fissile feed requirements which, in the case of U-Pu MOX fuels causes the Void Coefficient (VC) to become positive under transient conditions for a stockpile averaged Pu vector from the year 2055 …