Analytical procedures for the reliable determination of uranium isotopes employing a commercially available high resolution (HR)-ICP-OES installed in a glove box were developed and validated. To this end, nine commonly used U emission lines were tested for their potential to provide isotopic splitting of the U signal, thus providing isotopic information. Among all emission lines tested, the wavelength region around 424.4 nm offered the largest spread between individual U signals, i.e. 233 U, 235 U, 236 U, and 238 U. This study focused specifically on the reliable determination of the abundances of 235 U at 424.412 nm and 238 U at 424.437 nm in samples containing depleted, natural and slightly enriched U, but also included specimens with rather high (up to $90%) 235 U enrichments. Appropriate selection of the spectral background and accurate positioning of the peaks proved essential for obtaining reproducible U isotope ratios. The accuracy of the developed methodology was confirmed by the analysis of eight certified isotopic reference materials as well as eight reference samples that have been characterised in an accredited laboratory in-house using TIMS. In addition, this study highlights the potential of the developed HR-ICP-OES procedure for identifying nuclear sources of various U specimens via the analysis of 233 U (424.398 nm) and 236 U (424.423 nm). In contrast to the commonly used techniques, the methodology applied in this study does neither require the separation of U from the matrix prior to analysis nor the regular analysis of a reference sample with a known isotopic composition to correct for bias effects as it is the case for more sophisticated and precise mass spectrometric measurements. Nevertheless, HR-ICP-OES provides fit for purpose U isotopic information with reasonable accuracy (typically <1.5%) and precision ($1%) within a few minutes. As such, HR-ICP-OES can be employed as a reliable, fast screening tool to identify the U isotopic composition and as such, complements the more laborious TIMS analysis routinely employed for this purpose.

Carbon nanotubes (CNTs) have been shown to exhibit myriad chemical abilities. CNT materials are similar to activated carbon, but their regularized molecular structure has the potential for greater engineered control. An intriguing application is the removal and possible sequestration of radionuclides from nuclear plant waste streams. In this issue’s Viewpoint, researchers from three European research institutes overview the chemistry to date involving CNT materials interacting with radionuclides. In so doing, they sound a call to the environmental and materials research communities to further investigate the potential of functionalized CNTs and/or composites made from this novel substance.

No abstract

The choice of the analytical method for the determination of actinide isotopes in leachate solutions has to be made considering several parameters: detection limit for each isotope, sample preparation procedure in terms of duration and complexity, counting time and interferences. A leachate solution obtained by keeping a pellet of UO2 doped with 238Pu in contact with distilled water was investigated for the content of U and Pu isotopes by radiometric methods (alpha-, gamma-spectrometry and liquid scintillation counting). The results of the radiometric methods were compared with those obtained from the analysis performed by inductively coupled plasma mass spectrometry on-line to a system for chromatographic separation (IC-ICP-MS). The comparison confirmed that IC-ICP-MS is a powerful method for the detection of long-lived radionuclides. The radiometric methods have a detection limit two orders of magnitude lower than IC-ICP-MS in the case of short-lived radioisotopes mostly due to the low background in the detector. On the other hand, the sample preparation and the analysis duration are more time-consuming compared to IC-ICP-MS; moreover, not all isotopes can be determined by using only one radiometric technique.

No abstract