A review of nationwide radioactivity comparisons on gamma-ray spectrometry organized by the NIRP, China

• 188 samples were prepared and distributed to 39 participating laboratories.
• 528 radionuclide assays have been performed.
• Types of nuclides varied from natural to man-made radionuclides.
• A perceptible laboratory performance improvement is observed.

Six comparison exercises on radioactivity measurement by γ-spectrometry have been organized by NIRP in China since 2007. The type of measured nuclides changed from natural to man-made over this period. A total of 188 samples were prepared and distributed to 39 different participating laboratories and 528 radionuclide assays have been performed. A perceptible laboratory performance improvement was observed with the average percentage of acceptable scores being 87% in 2008, increasing to 92% in 2012.