Louis D. Schulte

Americium Separations from Nitric Acid Process Effluent Streams

Plutonium recovery operations offer several points at which americium removal may be attempted, and we are evaluating two classes of materials targeted at different steps in the process. Extraction chromatography resin materials loaded with three different alkylcarbamoyl phosphinates and phosphine oxides are assessed for Am removal efficiency and Am/Fe selectivity from 1–7M nitric acid solutions. Commercial and experimental anion exchange resins are evaluated for total alpha-activity removal from post-evaporator solutions whose composition, relative to the original nitric acid effluent, is reduced in acid and greatly increased in total salt content. With both classes of materials, americium and/or total-alpha reduction is sufficient to meet regulatory requirements even under sub-optimal conditions. Batch distribution coefficients and column performance data are presented.

Cleanup of hydrochloric acid waste streams from actinide processes using extraction chromatography

Abstract Extraction chromatography is under development as a method to lower actinide activity levels in hydrochloric acid (HCl) effluent steams. Successful application of this technique would allow recycle of the largest portion of HCl, while lowering the quantity and improving the form of solid waste generated. The extraction of plutonium and americium from HCl solutions was examined for several commercial and similar laboratory-produced resins coated with n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and either tributyl phosphate (TBP), or diamyl amylphosphonate (DAAP). Distribution coefficients for Pu and Am were measured by contact studies in 1–10 M HCl, while varying REDOX conditions, actinide loading levels, and contact time intervals. Significant differences in the actinide distribution coefficients, and in the kinetics of actinide removal were observed as a function of resin formulation.

Radiometallating Antibodies and Autoantigenic Peptides

We have developed methods to radiolabel large molecules, using porphyrins as bifunctional chelating agents for radiometals. The porphyrins are substituted with an N-benzyl group to activate them for radiometallation under mild reaction conditions. Porphyrins that have one functional group for covalent attachment to other molecules cannot cause crosslinking. We have examined the labeling chemistry for antibodies and have developed methods to label smaller biologically active molecules, such as autoantigenic peptides (fragments of the acetylcholine receptor), which are pertinent to myasthenia gravis research. The methods of covalent attachment of these bifunctional chelating agents to large molecules, the radiometallation chemistry, and biological characterization of the radiolabeled compounds will be discussed.

Recycle of scrap plutonium-238 oxide fuel to support future radioisotope applications

The Nuclear Materials Technology (NMT) Division of Los Alamos National Laboratory has initiated a development program to recover & purify plutonium-238 oxide from impure feed sources in a glove box environment. A glove box line has been designed and a chemistry flowsheet developed to perform this recovery task at large scale. The initial demonstration effort focused on purification of 238PuO2 fuel by HNO3/HF dissolution, followed by plutonium(III) oxalate precipitation and calcination to an oxide. Decontamination factors for most impurities of concern in the fuel were very good, producing 238PuO2 fuel significantly better in purity than specified by General Purpose Heat Source (GPHS) fuel powder specifications. A sufficient quantity of purified 238PuO2 fuel was recovered from the process to allow fabrication of a GPHS unit for testing. The results are encouraging for recycle of relatively impure plutonium-238 oxide and scrap residue items into fuel for useful applications. The high specific activity of pl...

Removal of Plutonium and Americium from Hydrochloric Acid Waste Streams Using Extraction Chomatography

Extraction chromatography is under development as a method to lower actinide activity levels in hydrochloric acid (HCl) effluent steams. Successful application of this technique for radioactive liquid waste treatment would provide a low activity feedstream for HCl recycle, reduce the loss of radioactivity to the environment in aqueous effluents, and lower the quantity and improve the form of solid waste generated.

Analysis of potential hazards associated with 241Am loaded resins from nitrate media

LANL has been contacted to provide possible assistance in safe disposition of a number of 241Am-bearing materials associated with local industrial operations. Among the materials are ion exchange resins which have been in contact with 241Am and nitric acid, and which might have potential for exothermic reaction. The purpose of this paper is to analyze and define the resin forms and quantities to the extent possible from available data to allow better bounding of the potential reactivity hazard of the resin materials. An additional purpose is to recommend handling procedures to minimize the probability of an uncontrolled exothermic reaction.

High Yield, One-Pot Syntheses of Symmetrical Diaryl- N , N -Dialkyl Carbamoylmethylphosphine Oxide (CMPO) Ligands

Abstract A simple one-pot high yield (˜70%) process is reported for the synthesis, in ˜100 g amounts, of a series of symmetrical diaryl-N,N-di-i-butylcarbamoylphosphine oxide (CMPO) actinide extractants, aryl = 4-t-butylphenyl, 4-trifluoromethylphenyl, 4-methoxyphenyl and 2,4,6-tri-i-propylphenyl.

Development program to recycle and purify plutonium-238 oxide fuel from scrap

Nuclear Materials Technology (NMT) Division of Los Alamos National Laboratory (LANL) has initiated a development program to recover & purify plutonium-238 oxide from impure sources. A glove box line has been designed and a process flowsheet developed to perform this task on a large scale. Our initial effort has focused on purification of 238PuO2 fuel that fails to meet General Purpose Heat Source (GPHS) specifications because of impurities. The most notable non-actinide impurity was silicon, but aluminum, chromium, iron and nickel were also near or in excess of limits specified by GPHS fuel powder specifications. 234U was by far the largest actinide impurity observed in the feed material because it is the daughter product of 238Pu by alpha decay. An aqueous method based on nitric acid was selected for purification of the 238PuO2 fuel. All aqueous processing used high purity reagents, and was performed in PTFE apparatus to minimize introduction of new contaminants. Impure 238PuO2 was finely milled, then di...