Patrick Thomas Martinez

Determination of inorganic cations in brine solutions by ion chromatography

The method for analysis of inorganic cations in brine solutions was developed. Ion chromatography is a well-established and accepted technique in the determination of a variety of inorganic ions. However, there are significant complications when ion chromatography is used to determine trace concentrations of inorganic ions in brine matrices. The brine solution in our study was made to simulate the solution from the Waste Isolation Pilot Plant. Instrumental parameters such as eluent composition, flow-rates, and sample loop volumes were investigated to arrive at the optimum condition for the determination of the cations with minimal dilution. Separation was carried out in a Dionex CG12A/CS12A with 8.25 mM H2SO4 as eluent at 1.2 ml/min flow-rate. Our results indicated that ion chromatography is an accurate and a good alternative method for the analysis of cations in brine solution.

Application of Micro-XRF for Nuclear Materials Characterization and Problem Solving

Micro-X-ray fluorescence (MXRF) used for >> 20 years To date MXRF has been underutilized for nuclear materials (NM) spatially-resolved elemental characterization. Scanning electron microscopy (SEM) with EDX much more common for NM characterization at a micro scale. But MXRF fills gap for larger 10s microns to cm{sup 2} scales. Will present four interesting NM applications using MXRF. Demonstrated unique value of MXRF for various plutonium applications. Although SEM has much higher resolution, MXRF clearly better for these larger scale samples (especially non-conducting samples). MXRF useful to quickly identify insoluble particles in Pu/Np oxide. MXRF vital to locating HEPA filter Pu particles over cm{sup 2} areas which were then extracted for SEM morphology and particle size distribution analysis. MXRF perfect for surface swipes which are far too large for practical SEM imaging, and loose residue would contaminate SEM vacuum chamber. MXRF imaging of ER Plutonium metal warrants further studies to explore metal elemental heterogeneity.

Morphological Comparison of U3O8 Ore Concentrates from Canada Key Lake and Namibia Sources

Uranium ore concentrates from two different sources were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The ore powders are referred to as Namibia (id. no. 90036, LIMS id. no. 18775) and Canada Key Lake (id. no. 90019, LIMS id. no. 18774). Earlier work identified the ores as the U₃O₈ phase of uranium oxide using x-ray diffraction. Both sets of powders were in the form of dark brown to black powder fines. However, the Canada Key Lake concentrates contained larger chunks of material on the millimeter scale that were easily visible to the unaided eye. The powders were mounted for SEM examination by hand dispersing a small amount onto conductive sticky tape. Two types of applicators were used and compared: a fine-tipped spatula and a foam-tipped applicator. The sticky tape was on a standard SEM “tee” mount, which was tapped to remove loose contamination before being inserted into the SEM.

Analytical Chemistry and Materials Characterization Results for Debris Recovered from Nitrate Salt Waste Drum S855793

Solid debris was recovered from the previously-emptied nitrate salt waste drum S855793. The bulk sample was nondestructively assayed for radionuclides in its as-received condition. Three monoliths were selected for further characterization. Two of the monoliths, designated Specimen 1 and 3, consisted primarily of sodium nitrate and lead nitrate, with smaller amounts of lead nitrate oxalate and lead oxide by powder x-ray diffraction. The third monolith, Specimen 2, had a complex composition; lead carbonate was identified as the predominant component, and smaller amounts of nitrate, nitrite and carbonate salts of lead, magnesium and sodium were also identified. Microfocused x-ray fluorescence (MXRF) mapping showed that lead was ubiquitous throughout the cross-sections of Specimens 1 and 2, while heteroelements such as potassium, calcium, chromium, iron, and nickel were found in localized deposits. MXRF examination and destructive analysis of fragments of Specimen 3 showed elevated concentrations of iron, which were broadly distributed through the sample. With the exception of its high iron content and low carbon content, the chemical composition of Specimen 3 was within the ranges of values previously observed in four other nitrate salt samples recovered from emptied waste drums.