Trace Actinide Signatures of a Bulk Neptunium Sample

In nuclear forensic analyses, measurements of actinideelementsin a sample can assist with identifying interdicted or unknown materials.While these radiochemical signatures have been extensively investigatedin uranium materials, less is known about bulk neptunium samples.This paper describes the measurement of trace actinide concentrationsand isotopic profiles in a Np-237 oxide sample. Uranium,plutonium, americium, and curium concentrations and isotopic profilesin the sample were determined and deemed potentially useful for distinguishingdifferent sources of Np-237. Several different potentialradiochronometry systems were also investigated; discordant resultsindicate that the Np sample was never completely purified of otheractinide elements, or that subsequent contamination of the sampleoccurred. Few prior studies of neptunium materials have been reported,and these data suggest that trace actinide constituents could provideunique signatures to identify material out of regulatory control.

Automated summary

In nuclear forensic analyses, measuring actinide elements in a sample is crucial for identifying unknown or banned materials. This paper focuses on the measurement of trace actinide concentrations and isotopic profiles in a neptunium-237 oxide sample and suggests that these data could be used to differentiate different sources of neptunium. However, inconsistent results from various radiochronometry systems indicate possible impurities or contamination in the sample. This study highlights the potential of trace actinide constituents in providing unique signatures for identifying illicit materials.