Np-237 analytical method using Np-239 tracers and application to a contaminated nuclear disposal facility

作者：Snow Mathew S^*; Morrison Samuel S; Clark Sue B; Olson John E; Watrous Matthew G

来源：Journal of Environmental Radioactivity, 2017, 172: 89-95.

DOI：10.1016/j.jenvrad.2017.02.018

• Np-237
• Np-239
• Subsurface disposal area

Environmental Np-237 analyses are challenged by low Np-237 concentrations and lack of an available yield tracer; we report a rapid, inexpensive Np-237 analytical approach employing the short lived Np-239 (t(1/2) = 23 days) as a chemical yield tracer followed by Np-237 quantification using inductively coupled plasma-mass spectrometry. Np-239 tracer is obtained via separation from a (243)AM stock solution and standardized using gamma spectrometry immediately prior to sample processing. Rapid digestions using a commercial, 900 W "Walmart" microwave and Parr microwave vessels result in 99.8 +/- 0.1% digestion yields, while chromatographic separations enable Np/U separation factors on the order of 10(6) and total Np yields of 95 +/- 4% (2 sigma). Application of this method to legacy soil samples surrounding a radioactive disposal facility (the Subsurface Disposal Area at Idaho National Laboratory) reveal the presence of low level Np-237 contamination within 600 m of this site, with maximum Np-237 concentrations on the order of 10(3) times greater than nuclear weapons testing fallout levels.

• 出版日期2017-6