Reliable determination of 237Np in environmental solid samples using 242Pu as a potential tracer

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Radiochemistry

Background:

• Accurate determination of neptunium-237 (Np-237) in environmental samples is crucial for radiological monitoring.
• Conventional methods for Np-237 analysis are often time-consuming and labor-intensive.

Purpose of the Study:

• To develop and validate a rapid analytical method for Np-237 determination in environmental solids.
• To investigate the use of automated sequential injection (SI) for anion exchange separation.
• To evaluate plutonium-242 (Pu-242) as a non-isotopic tracer for Np-237 yield monitoring.

Main Methods:

• Automated sequential injection (SI) system coupled with anion exchange chromatography.
• Investigation of Np-237 sorption behavior on AG 1-type anion exchangers.
• Use of Pu-242 as a tracer for chemical yield determination.
• Redox adjustment to tetravalent neptunium (Np(IV)) using disulfite-8M HNO(3).

Main Results:

• The degree of resin cross-linking significantly impacts separation efficiency and Np-237 chemical yields.
• Consistent Np-237 to Pu-242 chemical yield ratios (0.67 ± 0.04) were achieved.
• Tetravalent Np was stabilized for up to 5 days at 3°C.
• Analysis of reference materials showed good agreement with expected values.
• Each sample analysis was completed within 2.5 hours, reducing labor intensity.

Conclusions:

• The developed SI-based anion exchange method provides rapid and reliable determination of Np-237 in environmental solids.
• Pu-242 is a suitable non-isotopic tracer for monitoring Np-237 chemical yields.
• The method is advantageous for emergency situations requiring swift analysis.