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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,801 records · Page 100
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Uranium Zirconium Alloy Dissolution

This Special Instructions provides a standard method to dissolve irradiated or unirradiated UZr alloys. The scope of this procedure was developed to facilitate total dissolution of UZr solid samples with and without cladding materials.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

TEX-HEU Baseline Assemblies: Highly Enriched Uranium Plates with Polyethylene Moderator and Polyethylene Reflector (IER-297 CED-4b Report)

This experiment provides the baseline experimental configurations for TEX-HEU. The purpose of the TEX-HEU design is to provide multiple configurations that span the entire neutron energy spectrum and can be easily modified to incorporate diluent materials. Future experiments utilizing the TEX-HEU design are planned to incorporate hafnium, lithium, and chlorine as diluent materials. Five experimental configurations were judged to be acceptable critical benchmark experiments.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

Watershed Controls on Uranium Concentrations Tied into Natural Organic Matter and Iron Interactions in Streambeds and Wetlands

The focus of our project is on understanding natural organic matter (NOM) properties and their influence on U remobilization/immobilization, considering the important roles of watersheds hydrology and microbial dynamics. Laboratory and analytical techniques assessed these dynamic processes at ambient U and OM concentrations, in order to find favorable environmental settings that make the wetland, stream sediment, and flocs an organic C and/or U sink or source.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Studying f-Electron Contributions in Thorium and Uranium Containing Molecules

The pure rotational spectra of several actinide-containing compounds have been improved upon and, in two cases, been recorded for the first time. The diatomic molecules HfS and ThS have been studied in their ground electronic states but high vibrationally excited states. The results have yielded very accurate locations of the minima of the potential energy curves. The asymmetric molecules OThS and UO2S have been prepared by laser ablation synthesis and their pure rotational spectra recorded for the first time. Precise information pertinent to the geometric and electronic structure of these molecules has been obtained and is compared with other, newly recorded and related species such as OCeS.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Water-Quality Issues Related to Uranium In Situ Recovery Sites

Batch tests, column tests, and predictive reactive transport modeling can be done before ISR begins as part of the decision making/permitting process by bracketing possible post-restoration conditions; Help address stakeholder concerns; The best predictions require actual restored groundwater in contact with the downgradient solid phase; Resulting modeling provides a range of natural attenuation rates and assists with designing the best locations and time frames for continued monitoring; Field pilot tests are the best field-scale data and can provide the best model input and calibration data

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Automated Characterization of Uranium-Molybdenum Fuel Microstructures

Currently, performance evaluators rely on visual inspection or manual segmentation to assess most parameters of interest within an irradiated microstructure. Automating this process has the potential to significantly speed up the data extraction process, enhance its reliability, and improve its correctness. Automatic image segmentation of target features is a critical tool for providing measurements of features that may be used to increase the fidelity of fuel performance modeling. This summary will present the progress made in developing and testing automated image processing routines capable of fully characterizing the presence of fission gas bubbles in irradiated U-Mo plate-type fuel microstructures.

Image Processing↗
DOE OSTI2013

Automated Groundwater Monitoring of Uranium at the Hanford Site, Washington - 13116

An automated groundwater monitoring system for the detection of uranyl ion in groundwater was deployed at the 300 Area Industrial Complex, Hanford Site, Washington. The research was conducted to determine if at-site, automated monitoring of contaminant movement in the subsurface is a viable alternative to the baseline manual sampling and analytical laboratory assay methods currently employed. The monitoring system used Arsenazo III, a colorimetric chelating compound, for the detection of the uranyl ion. The analytical system had a limit of quantification of approximately 10 parts per billion (ppb, μg/L). The EPA's drinking water maximum contaminant level (MCL) is 30 ppb [1]. In addition to the uranyl ion assay, the system was capable of acquiring temperature, conductivity, and river level data. The system was fully automated and could be operated remotely. The system was capable of collecting water samples from four sampling sources, quantifying the uranyl ion, and periodically performing a calibration of the analytical cell. The system communications were accomplished by way of cellular data link with the information transmitted through the internet. Four water sample sources were selected for the investigation: one location provided samples of Columbia River water, and the remaining three sources provided groundwater from aquifer sampling tubes positioned in a vertical array at the Columbia River shoreline. The typical sampling schedule was to sample the four locations twice per day with one calibration check per day. This paper outlines the instrumentation employed, the operation of the instrumentation, and analytical results for a period of time between July and August, 2012. The presentation includes the uranyl ion concentration and conductivity results from the automated sampling/analysis system, along with a comparison between the automated monitor's analytical performance and an independent laboratory analysis. Benefits of using the automated system as an alternative to traditional sample collection and analysis includes the following: - Field observations that provide more characterization information than is possible using traditional monitoring methods. - Potentially significant reductions in labor and analytical costs if traditional methods are complemented by automated systems. - The reduced cost of acquiring samples will allow for more frequent collection of samples that may be automatically introduced into real-time graphical flux programs allowing site managers to observe the changes in contaminant concentrations during remediation projects and across discrete river stage events. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

On-Site Pilot Study - Removal of Uranium, Radium-226 and Arsenic from Impacted Leachate by Reverse Osmosis - 13155

Conestoga-Rovers and Associates (CRA-LTD) performed an on-site pilot study at the Welcome Waste Management Facility in Port Hope, Ontario, Canada, to evaluate the effectiveness of a unique leachate treatment process for the removal of radioactive contaminants from leachate impacted by low-level radioactive waste. Results from the study also provided the parameters needed for the design of the CRA-LTD full scale leachate treatment process design. The final effluent water quality discharged from the process to meet the local surface water discharge criteria. A statistical software package was utilized to obtain the analysis of variance (ANOVA) for the results from design of experiment applied to determine the effect of the evaluated factors on the measured responses. The factors considered in the study were: percent of reverse osmosis permeate water recovery, influent coagulant dosage, and influent total dissolved solids (TDS) dosage. The measured responses evaluated were: operating time, average specific flux, and rejection of radioactive contaminants along with other elements. The ANOVA for the design of experiment results revealed that the operating time is affected by the percent water recovery to be achieved and the flocculant dosage over the range studied. The average specific flux and rejection for the radioactive contaminants were not affected by the factors evaluated over the range studied. The 3 month long on-site pilot testing on the impacted leachate revealed that the CRA-LTD leachate treatment process was robust and produced an effluent water quality that met the surface water discharge criteria mandated by the Canadian Nuclear Safety Commission and the local municipality. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Glass-Ceramic Waste Forms for Uranium and Plutonium Residues Wastes - 13164

A program of work has been undertaken to treat plutonium-residues wastes at Sellafield. These have arisen from past fuel development work and are highly variable in both physical and chemical composition. The principal radiological elements present are U and Pu, with small amounts of Th. The waste packages contain Pu in amounts that are too low to be economically recycled as fuel and too high to be disposed of as lower level Pu contaminated material. NNL and ANSTO have developed full-ceramic and glass-ceramic waste forms in which hot-isostatic pressing is used as the consolidation step to safely immobilize the waste into a form suitable for long-term disposition. We discuss development work on the glass-ceramic developed for impure waste streams, in particular the effect of variations in the waste feed chemistry glass-ceramic. The waste chemistry was categorized into actinides, impurity cations, glass formers and anions. Variations of the relative amounts of these on the properties and chemistry of the waste form were investigated and the waste form was found to be largely unaffected by these changes. This work mainly discusses the initial trials with Th and U. Later trials with larger variations and work with Pu-doped samples further confirmed the flexibility of the glass-ceramic. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

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