Brienne N. Seiner

Integrated separation scheme for measuring a suite of fission and activation products from a fresh mixed fission and activation product sample

Mixed fission and activation materials resulting from various nuclear processes and events contain a wide range of isotopes for analysis spanning almost the entire periodic table. This work describes the production of a complex synthetic sample containing fission products, activation products, and irradiated soil, and determines the percent chemical recovery of select isotopes through the integrated chemical separation scheme. Based on the results of this experiment, a complex synthetic sample can be prepared with low atom/fission ratios and isotopes of interest accurately and precisely measured following an integrated chemical separation method.

Analysis of 161Tb by radiochemical separation and liquid scintillation counting

The determination of 161Tb activity is problematic due to its very low fission yield, short half-life, and the complication of its gamma spectrum. At AWE, radiochemically purified 161Tb solution was measured on a PerkinElmer 1220 QuantulusTM Liquid Scintillation Spectrometer. Since there was no 161Tb certified standard solution available commercially, the counting efficiency was determined by the CIEMAT/NIST Efficiency Tracing method. The method was validated during a recent inter-laboratory comparison exercise involving the analysis of a uranium sample irradiated with thermal neutrons. The measured 161Tb result was in excellent agreement with the result using gamma spectrometry and the result obtained by Pacific Northwest National Laboratory.

Activation product analysis in a mixed sample containing both fission and neutron activation products

This work describes a radiochemical separation procedure for the determination of gold (Au), platinum (Pt), tantalum (Ta), and tungsten (W) activation in the presence of fission products. Chemical separations result in a reduction in the minimum detectable activity by a factor of 287, 207, 141, and 471 for 182Ta, 187W, 197Pt, and 198Au respectively, with greater than 90% recovery for all elements. These results represent the highest recoveries and lowest minimum detectable activities for 182Ta, 187W, 197Pt, and 198Au from mixed fission-activation product samples to date, enabling considerable refinement in the measurement uncertainties for neutron fluences in highly complex sample matrices.Graphical Abstract

Fission product analysis of HEU irradiated within a boron carbide capsule: comparison of detection methodology at PNNL and AWE

The fission products from HEU formed under a fast-pooled neutron spectrum generated using a boron carbide shield were analyzed at Pacific Northwest National Laboratory and the Atomic Weapons Establishment. The results from each laboratory using chemical separation, high-purity germanium gamma spectroscopy and/or Compton suppression gamma spectroscopy are compared with the potential benefits and limitations of the different gamma spectroscopy methods discussed.

Kinetic phosphorescence analysis to quantify europium and terbium

The ability to accurately quantify europium and terbium may be confounded by the presence of other lanthanides when using spectroscopic techniques such as optical emission spectroscopy, especially at microgram and sub microgram levels. Kinetic phosphorescence analysis (KPA) offers a method to avoid these interferences during measurement of trace levels. This study examined analysis parameters using KPA for europium and terbium by testing the effects of different acids, molarities, and the use of a complexing agent to determine the ideal conditions and limits of detection for each analyte in matrices containing various mixtures of lanthanides.