Analysis of plutonium isotope ratios including 238 Pu/ 239 Pu in individual U–Pu mixed oxide particles by means of a combination of alpha spectrometry and ICP-MS

Electrochemical detector based on a modified graphite electrode with phthalocyanine for the elemental analysis of actinides

The quantification of actinides in aqueous solutions involves complex and expensive separation processes. Electrochemical methods have been widely used for the quick and accurate identification and quantification of organic and inorganic compounds directly or indirectly. Therefore, this work proposes the use of modified graphite with phthalocyanine for electrochemical detection and quantification of Th, U, Pu, Am, and Cm, in aqueous media by cyclic voltammetry. The electrodes were characterized by Raman and infrared spectroscopy, and the cyclic voltammetry data were modeled with Aoki's model. The detection limits (DL) and the quantification limits (QL) reached by the electrochemical detection of these actinides were of the order of ppt. Aoki's model fitted perfectly with the experimental data. The functionalization of graphite electrodes promotes the formation of phthalic anhydride, and the phthalocyanine is anchored on the epoxy groups of the graphite. The electrochemical detection process of these actinides is indirect. This electrochemical detector is cheap and disposable and can be an alternative for an initial characterization of actinides in liquid waste.

Simultaneous Isotopic Analysis of U, Pu, and Am in Spent Nuclear Fuel by Resonance Ionization Mass Spectrometry

Solid samples of spent nuclear fuel were analyzed for actinide isotopic composition by resonance ionization mass spectrometry. Isotopes of U, Pu, and Am were simultaneously quantified using a new method that removes and/or resolves the isobaric interferences at ²³⁸U/²³⁸Pu and ²⁴¹Pu/²⁴¹Am without sample preparation other than cutting and mounting small (∼10 μm) samples. Trends in burnup and neutron capture product distributions were correlated with the sampling positions inside the reactor. The results show the skin effect, in which the core and near-edge regions of a fuel pellet exhibit strong differences in actinide concentrations and isotope distributions due to differences in the neutron energy spectra between the pellet rim and the core. While no elemental concentration measurements were made, the ability to measure the ²³⁸Pu/²³⁹Pu ratio in the presence of a 7400× excess of ²³⁸U enabled an estimate of the enhancement in Pu concentration due to the skin effect at the rim of the pellet.

Alpha spectrometry and liquid scintillation counting for the measurement of 238Pu, 239Pu, 240Pu, 241Pu, 242Pu and age

A method for the measurement of the isotopic composition and time since last chemical separation (age) of plutonium is presented. The method includes alpha spectrometric measurement of ²³⁸Pu, ²³⁹Pu and ²⁴⁰Pu where the ratio of ²³⁹Pu and ²⁴⁰Pu was determined using spectral deconvolution, and liquid scintillation counting of ²⁴¹Pu, after chemical separation of plutonium and americium. For the age determination, the ²⁴¹Pu determined using liquid scintillation counting was combined with alpha spectrometric measurement of ²⁴¹Am. The results of the isotopic composition were compared with certified reference materials with known isotopic composition, and the results of the age determination were compared with literature values of the separation dates.