LABORATORY STANDARD FOR RADIONUCLIDES IN NUCLEAR WASTE

A laboratory standard for the determination of long-lived radionuclide s in nuclear waste has been prepared using concrete as matrix. It will be used to check sample preparation procedures, chemical separations and methods for the determination of nuclides, e.g., nuclear counting techniques or mass spectrometry. The material chosen was a fine-graine d ready-to-use cement mixture, to which the following radionuclides we re added: Co-60 and Cs-137 as gamma-ray-emitting nuclides Tc-99, Sr-90 and Fe-55 as radionuclides emitting pure beta-radiation or low-energy electrons, and U-233, Np-237, Pu-238 and Am-241 as alpha-emitters. Ca re was taken to attain a homogeneous distribution of the nuclides in t he standard material. Pieces of about 1 g were formed as suitable and representative samples. Repeated analyses were carried out with the st andard to check its homogeneity. The analytical procedures are describ ed in brief. The pieces of the standard material have the same content of nuclides within +/- 5% at a 95% level of confidence.