Development of metal radioactive liquid reference material for proficiency test.

Area of Science:

• Nuclear Chemistry
• Radiochemistry
• Environmental Science

Background:

• Nuclear power plants generate metallic waste requiring accurate radiation measurement for safe operation and decommissioning.
• Existing reference materials may not adequately represent the complex matrix of metallic radioactive waste.
• Quality assurance in radioactive waste management is crucial for regulatory compliance and environmental protection.

Purpose of the Study:

• To develop and validate liquid reference materials for metallic radioactive waste.
• To assess the performance of laboratories in measuring key radionuclides in metallic waste.
• To establish a basis for future certified reference material (CRM) development.

Main Methods:

• Preparation of liquid reference materials by dissolving stainless steel components (Fe, Ni, Cr, Mn) and incorporating standard radioactive sources (Cs-134, Cs-137, Co-60, Sr-90).
• Comparison of theoretical and measured massic activities of gamma and beta emitters.
• Proficiency testing of three laboratories using the developed reference materials, with results evaluated via Z-score.

Main Results:

• Good agreement was observed between theoretical and measured values for gamma and beta emitters within a one-sigma confidence interval.
• Proficiency testing showed good agreement for Cs-137 and Co-60, but underestimation for Cs-134 and overestimation for Sr-90 by participating labs.
• Identified specific radionuclides requiring improved measurement accuracy in radioactive metal waste analysis.

Conclusions:

• The developed metal radioactive liquid reference materials are suitable for quality assurance in radiation measurements of metallic waste.
• The study identified areas for improvement in laboratory performance for specific radionuclides.
• The materials show promise for future registration as certified reference materials (CRMs) for radioactive metal waste analysis.