Trace Actinide Signatures of a Bulk Neptunium Sample

Area of Science:

• Nuclear Chemistry
• Radiochemistry
• Forensic Science

Background:

• Actinide element measurements aid in identifying unknown or interdicted nuclear materials.
• Radiochemical signatures of uranium are well-studied, but less is known about bulk neptunium (Np) samples.
• Characterizing trace actinide constituents in neptunium is crucial for nuclear forensics.

Purpose of the Study:

• To measure trace actinide concentrations and isotopic profiles in a 237Np oxide sample.
• To assess the utility of these trace elements and isotopes for distinguishing different sources of 237Np.
• To investigate potential radiochronometry systems for neptunium dating.

Main Methods:

• Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for elemental and isotopic analysis.
• Radiochemical separation techniques for isolating actinide elements.
• Alpha spectrometry for isotopic abundance measurements.

Main Results:

• Concentrations and isotopic profiles of uranium, plutonium, americium, and curium were determined in the 237Np sample.
• These trace actinide signatures were found to be potentially useful for source attribution of 237Np materials.
• Discordant radiochronometry results suggested incomplete purification or subsequent contamination of the neptunium sample.

Conclusions:

• Trace actinide constituents in neptunium samples can provide unique signatures for material identification.
• Characterization of these trace elements is vital for nuclear forensic applications.
• Further research is needed to refine analytical methods and understand the implications of impurities and contamination in neptunium materials.