Separation of Americium in High Oxidation States from Curium Utilizing Sodium Bismuthate.

A simple separation of americium from curium would support closure of the nuclear fuel cycle, assist in nuclear forensic analysis, and allow for more accurate measurement of neutron capture properties of (241)Am. Methods for the separation of americium from curium are however complicated and time-consuming due to the similar chemical properties of these elements. In this work a novel method for the separation of americium from curium in nitric acid media was developed using sodium bismuthate to perform both the oxidation and separation. Sodium bismuthate is shown to be a promising material for performing a simple and rapid separation. Curium is more strongly retained than americium on the undissolved sodium bismuthate at nitric acid concentrations below 1.0 M. A separation factor of ∼90 was obtained in 0.1 M nitric acid. This separation factor is achieved within the first minute of contact and is maintained for at least 2 h of contact. Separations using sodium bismuthate were performed using solid-liquid extraction as well as column chromatography.

Group hexavalent actinide separation from lanthanides using sodium bismuthate chromatography.

Advanced used nuclear fuel (UNF) reprocessing strategies are limited by the complex radiochemical separations and engineering required to achieve the separation of actinides (An) from neutron scavenging lanthanides (Ln). The accessibility of the hexavalent oxidation state for the actinides (U - Am) provides a pathway to achieving a group hexavalent actinide separation from the trivalent lanthanides and Cm. The solid oxidant and ion exchanger, sodium bismuthate (NaBiO3), has been demonstrated to quantitatively oxidize and separate Am from trivalent Cm in a column chromatographic system. This work expands on the use of NaBiO3 chromatography to characterize the adsorption, kinetic, and elution behavior of U, Pu, and Eu. Separation factors over 200 with rapid kinetics were observed at dilute nitric acid concentrations with a complete An/Ln separation achieved in under an hour. The adsorption and chromatographic behavior of key fission products present in various reprocessing raffinates was characterized which demonstrated potential application of a NaBiO3-based separation following a TRUEX process.

Adsorption Behavior of Pu(IV), Am(III), Cm(III), and U(VI) on Desferrioxamine B-immobilized Micropolymer and Its Applications in the Separation of Pu(IV).

The adsorption properties of Pu(IV), Am(III), Cm(III), and U(VI) on desferrioxamine B-immobilized micropolymeric resin (DMPs) and adsorbed species were elucidated using thermodynamic constants and log ß values. This allowed the determination of adsorption characteristics (91, 95, 88, and 97% for Pu(IV), Am(III), Cm(III), and U(VI), respectively) and individual pH-independent adsorption properties. Pu(IV) could be separated from Am(III), Cm(III), and U(VI) at pH 2. The separation of Pu(IV) from Am(III), Cm(III), and U(VI) was achieved by controlling the pH of the solution using a single resin.

Rapid method to determine Polonium-210 in urban matrices.

A rapid method for the determination of polonium-210 in urban matrices has been developed that can be used following a radiological event. Samples such as concrete, soil and granite are fused with sodium hydroxide to minimize polonium volatility during sample digestion and to achieve complete sample dissolution. Complete dissolution of samples is important to ensure method ruggedness. Polonium is concentrated and separated from the sample matrix using an iron hydroxide precipitation and extraction chromatography and subsequently measured by alpha spectrometry following microprecipitation with bismuth phosphate. The chromatographic separation removes alpha emitting interferences and matrix constituents which can adversely impact the measurement via alpha spectrometry.

Novel rapid oxidizing fusion method to determine Polonium-210 in air filters.

A rapid method for the determination of polonium-210 in air filters has been developed for use following a radiological event and for routine environmental monitoring. Air filter samples, including cellulose and glass fiber, are fused with a sodium or potassium nitrate/sodium hydroxide flux material. The alkaline matrix minimizes polonium volatility during sample digestion steps, while efficiently dissolving the air filter and inorganic matter implanted on the filter. The addition of nitrate to the flux destroys organic material which can decrease Polonium recovery during precipitation, extraction and source preparation steps. Polonium is concentrated and separated from the sample matrix using an iron hydroxide precipitation and extraction chromatography with DGA Resin. Polonium-210 is subsequently measured by alpha spectrometry following rapid microprecipitation with bismuth phosphate. The new method employs extraction chromatographic purification to remove alpha emitting interferences and sample matrix constituents which can interfere with 210Po measurements using alpha spectrometry. The novel blend of sodium hydroxide and alkali metal nitrate digests the air filters quickly and effectively.

Rapid method to determine plutonium, neptunium, americium and curium in granite samples.

A fast method for determination of plutonium, neptunium, americium and curium isotopes in granite has been developed for use following a radiological event. Granite samples are fused with sodium hydroxide to achieve complete dissolution, critical if refractory particles are present. Rapid precipitation steps are utilized to preconcentrate the actinide isotopes and remove sample matrix interferences. Plutonium, neptunium, and americium/curium are separated using innovative extraction chromatography and measured by alpha spectrometry. The sample preparation time is less than four hours.

A Rapid Method for Quantification OF 242Pu in Urine Using Extraction Chromatography and ICP-MS.

Occupational exposure to plutonium is generally monitored through analysis of urine samples. Typically, plutonium is separated from the sample and other actinides, and the concentration is determined using alpha spectroscopy. Current methods for separations and analysis are lengthy and require long count times. A new method for monitoring occupational exposure levels of plutonium has been developed, which requires fewer steps and overall less time than the alpha spectroscopy method. In this method, the urine is acidified, and a Pu internal standard is added. The urine is digested in a microwave oven, and plutonium is separated using an Eichrom TRU Resin column. The plutonium is eluted, and the eluant is injected directly into the Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Compared to a direct "dilute and shoot" method, a 30-fold improvement in sensitivity is achieved. This method was validated by analyzing several batches of spiked samples. Based on these analyses, a combined standard uncertainty plot, which relates uncertainty to concentration, was produced. The MDA95 was calculated to be 7.0 × 10 µg L, and the Lc95 was calculated to be 3.5 × 10 µg L for this method.