Cavity Ring-Down\nSpectroscopy Analysis of Radiocarbon\nfrom Nuclear Waste Materials

Radiocarbon analysis of nuclear waste produced in nuclear\nfacilities\nlacks fast, in situ detection methods. Moreover, the amount of radiocarbon\ndesorbing from graphitic waste is not well known. In this study, we\ndemonstrate the use of mid-infrared cavity ring-down spectroscopy\ncombined with an automatic sample processing unit as a method to examine\nradiocarbon concentration in three types of nuclear waste: spent ion-exchange\nresin, graphite, and graphite outgassing in sealed storage crates.\nThe solid samples were gasified, which allowed analyzing the effect\nof heating on the radiocarbon outgassing from the samples. The presented\nmethod also enabled examination of molecular speciation of the radiocarbon\nin the samples. The method performed well with the graphite and gaseous\nsamples, but the analysis of the spent ion-exchange resin did not\nproduce repeatable results due to high N<sub>2</sub>O concentrations.\nIn the future, the presented method can be used <i>in situ</i> at nuclear facilities and expanded to a wider variety of sample\nmaterials than those presented here.