Environmental monitoring for safeguards using k(0)-standardized neutron activation analysis

Multi-elemental analysis of samples containing uranium by Instrumental Neutron Activation Analysis (INAA) has been generally known as a problematic task due to the numerous radioisotopes produced from the uranium fission when the sample is irradiated with thermal neutrons. In k(0)-standardized NAA (k(0)-NAA), it is possible to correct for this effect through the introduction of k(0)-fission factors. In this work, the aim was to determine the feasibility of k(0)-NAA as a screening technique for accurate and isotopic ratio determination (we further refer to the technique as k(0)-UNAA) and where k(0)-UNAA could be positioned versus the other screening techniques. In k(0)-UNAA, we use an adapted formalism to determine the n(U-235)/n(U-238)-ratio. Several swipe samples spiked with different isotopic ratios were analyzed and demonstrate the feasibility of k(0)-UNAA as a accurate and reliable screening method for the quantification of environmental samples up to several tens of ng. At these levels the uranium concentration can be quantified with a reasonable uncertainty and reliable n(U-235)/n(U-238) isotopic ratio analysis could also be performed.

Publication year:2010

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