Uranium and plutonium solution assays by transmission‐corrected x‐ray fluorescence spectrometry

Abstract

An x-ray fluorescence analysis technique was developed for uranium and plutonium solutions, which compensates for variations in the absorption of the exciting gamma rays and fluorescent x-rays. 57Co is used to excite efficiently the K lines of the elements, and a mixed 57Co plus 153Gd transmission source is used to correct for variations in absorption. The absorption correction is a unique feature of the technique which permits accurate calibration with a single solution standard and the measurement of a wide range of concentrations (up to 300 g l−1). Without this correction procedure, up to six solution standards are required to correct for non-linearity over this concentration range. In addition, other elements present in the specimens and not present in the standards would otherwise reduce the accuracy or even invalidate the analyses. Specially designed equipment incorporates a planar intrinsic germanium detector, excitation and transmission radioisotopes and specimen holder. The apparatus can be inserted into a rubber glove of a glove-box, keeping the apparatus outside and the solutions inside the glove-box, thereby protecting the user and the equipment from possible contamination. This technique will be tested at the Bochvar Institute of Inorganic Materials in Moscow for possible use in the Russian complex of nuclear facilities. This is part of a cooperative program between laboratories in the USA and Russia to strengthen systems of nuclear materials protection, control and accountability (MPC&A) in both countries. A part of this program is to measure accurately and track inventories of materials, hence the need for good non-destructive analytical techniques. Copyright © 1999 John Wiley & Sons, Ltd.