Detection of Fuel Release in a Nuclear Accident: A Method for Preconcentration and Isolation of Reactor-Borne 239Np Using Ion-Specific Extraction Chromatography

Abstract

Although actinides are the most informative elements with respect to the nature of a nuclear accident, plutonium analysis is complicated by the background created by fallout from atmospheric nuclear explosions. Therefore, we propose 239Np, a short-lived actinide that emits several γ rays, as a preferred proxy. The aim of this study was to screen ion specific extraction chromatography resins (RE-, TEVA-, UTEVA-, TRU-, and Actinide-Resin) for the highest possible recovery and separation of trace amounts of 239Np from samples with large activities of fission products such as radiocesium, radioiodine, and, most importantly, radiotellurium, the latter of which causes spectral interference in gamma spectrometry through overlapping peaks with 239Np. The investigated environmental media for these separations were aqueous solutions simulating rainwater and soil. Spiked samples containing 239Np and the aforementioned volatile radionuclides were separated through extraction chromatographic columns to ascertain the most effective means of separating 239Np from other fission products for detection by gamma spectroscopy. We propose a method for nuclear accident preparedness based on the use of Eichrom's RE-Resin. The proposed method was found most effective for isolating 239Np from interfering radionuclides in both aqueous solution and soil using 8 M HNO3 as the loading solution and H2O as the eluent. The RE-Resin outperforms the more commonly used TEVA-Resin because the TEVA-Resin showed a higher affinity for interfering radiotellurium and radioiodine. (Figure Presented).