J. A. Carter

Simultaneous Plutonium and Uranium Isotopic Analysis from a Single Resin Bead - A Simplified Chemical Technique for Assaying Spent Reactor Fuels

Abstract The method uses basic anion resin to adsorb plutonium and uranium from 7–8 M HNO3 solutions containing dissolved spent reactor fuels. After equilibrating the resin with the solution, a single bead is used to determine the isotopic composition of plutonium and uranium on sample sizes as small as 10−9 to 10−10 g of each element per bead. Isotopic measurements are essentially free of isobaric interferences and fission product contamination in the mass spectrometer is eliminated. A very small aliquot of dissolver solution containing 10−6 g of U and 10−8 g of Pu is sufficient sample for chemically preparing several resin beads. A single prepared bead is loaded onto a rhenium filament and analyzed in a two-stage mass spectrometer using pulse counting for ion detection to obtain the high sensitivity required. Total quantity of the elements, in addition to isotopic abundances, can be determined by isotope dilution. Other areas where the method may be useful are: in plutonium production, isotope separatio...

The analysis of explosives by tandem mass spectrometry

Data obtained via tandem mass spectrometry are reported for ions derived from several explosives and related compounds. Electron impact ionization, isobutane chemical ionization, and negative chemical ionization methods were used to form ions from each of the compounds studied. These compounds include o-, m-, and p-nitrotoluene; m-dinitrobenzene; 2,4-dinitrotoluene; 2,4,6-trinitrotoluene; 2,4-dinitrophenol; picric acid; 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX); 1,3,5,7-tetranitro-1,3,5,7-tetra-azacyclooctane (HMX); nitroglycerin; pentaerythritol tetranitrate (PETN); and ethylene glycol dinitrate (EGDN). For a given ionization method each class of compounds (that is, nitrobenzenes, heterocyclic nitramines, and nitrate esters) shows common decompositions. This promises to facilitate rapid screening for particular types of explosives by the neutral loss scanning procedure. Of the three ionization methods employed, electron impact ionization is least suitable for analysis of explosives by tandem mass spectrometry. Positive and negative chemical ionization methods, in contrast, tend to generate the types of ions most useful for analysis by tandem mass spectrometry.

A simple method to enhance thermal emission of metal ions

Abstract A simple technique has been developed to enhance ion yields from Pu and U during single-filament thermal analysis. A small amount of Re powder is slurried with a solution of sucrose in water and added to the canoe-shaped filament. Forcing the Pu or U through the resulting ReC layer leads to enhanced ion emission and to significantly reduced fractionation.

Uranium series dating of stalagmites from Blanchard Springs Caverns, U.S.A.

Abstract Because stalagmites are enriched in 234U beyond the equilibrium value at the time of deposition, they are potentially datable by measuring their progress toward equilibrium. Procedures for uranium-thorium and uranium disequilibrium dating of speleothems were developed, making use of alpha spectrometry for thorium determinations and mass spectrometry for uranium determinations. The stalagmites tested were generally beyond the age range of the U-Th age dating method and, as a result, 234U/238U ratios provided the most useful dating technique. The estimated age range for a stalagmite from Blanchard Springs is 135,000 to 785,000 years BP with an interval of slow or suspended growth from about 320,000 to 570,000 years BP.

A Bulk Resin Bead Procedure To Obtain Uranium And Plutonium From Radioactive Solutions For Mass Spectrometric Analysis

A method is described for extracting representative uranium and plutonium samples from highly radioactive solutions for isotopic mass spectrometric analysis. Anion resin beads in the nitrate form are used to effect separation from fission products and other actinides. Conditions required to achieve separation are proper adjustment of the uranium and nitric acid concentrations. Once uranium and plutonium are adsorbed, each bead serves as a sample for mass spectrometric analysis, with plutonium and uranium being run sequentially from the same bead. Quantitative determination of the two elements is effected through the technique of isotopic dilution.

Analysis of Resin-Bead Loaded U And PU Samples with a Single-Stage Mass Spectrometer

Abstract The resin bead sample loading technique has been applied to a conventional single-stage mass spectrometer equipped with pulse counting. Isotopic data obtained for U and Pu are comparable to those obtainable from similar instruments using conventional techniques.

Isotope Dilution Resin Bead Mass Spectrometry—An Ultra Trace Technique for Measuring Nuclides in Three-Mile Island Water

Abstract From the onset of the Three-Mile Island reactor incident (March 28, 1979), the distinct possibility existed that actinide and fission product pollutants could escape into the surrounding environment. Experienced analytical chemists in command of techniques which achieve the highest sensitivity were called upon for assistance in performing analyses. Cooling water was analyzed for uranium and plutonium, certain fission products, additives, and possible corrosion products by isotope dilution mass spectrometry. In particular, the thermal emission isotope dilution technique, in which an anion exchange resin bead was used to concentrate the uranium and plutonium, provided technical information on samples orders of magnitude smaller than those necessary for conventional counting techniques. The resin-bead-loaded sample acts as a point source in a pulse counting two-stage high abundance sensitivity mass spectrometer, enhancing the sensitivity so that levels as low as 10−13 plutonium and 10−11M uranium co...

Separated isotopes as internal standards in spark source mass spectrometry

Abstract The use of separated stable isotopes as internal standards in spark source mass spectrometry is described. This method is useful for solution samples and complements the more classical isotope dilution technique. For powdered or insoluble samples, the isotopes are dried onto a conducting matrix material-usually high purity silver powder-followed by homogenization of the sample with this «spiked’ matrix. The resulting mixture can then be pressed into solid electrodes and analyzed by spark source mass spectrometry. This technique has proven useful for the determination of mononuclidic elements such as Co, As, and Mn in a variety of samples, and for multielement analysis of coal ash and fly ash, with a minimum of sample handling and resultant contamination. Use of an isotope which has a mass near to that of the element being measured gives more precise and accurate analyses than the common technique of using one internal standard.

Determining Ppb Mercury Concentrations Using a Spark-Source Mass Spectrometer Sample Changer

Abstract A probe-type sample changer has been added to a spark-source mass spectrometer enabling the rapid determination of ppb levels of mercury by isotope dilution. The technique has also been used for determining Cd, Hg, and Zr in samples of air, water, and urine.

Ion Implantation Standards as a Spark Source Mass Spectrometric Surface Analysis Calibration Technique: The Analysis of B in Irradiated Zircaloy-2

Abstract Ion implantation standards were used to calibrate a spark source mass spectrometer (SSMS) near surface region analytical method. Standards were prepared by ion implanting 11B+ at 100 keV into Zircaloy-2 at doses in the 3 × 1015 to 3 × 1016 11B atoms/cm2 range. The analytical method was predicated on the idea that both standards and samples could be sparked in a SSMS under essentially identical and reproducible conditions. Calibration plots gave linear log-log results for plots of 11B+/122Sn+ versus B concentration in the standards. Calibration plots were determined on the basis of 5 to 6 replicate determinations for 3 different implant standard concentration levels. A series of irradiated Zircaloy-2 cladding samples were analyzed and shown to contain not more than 0.06 μg/cm2 total B in the near surface region.