Laboratory standard for radionuclides in nuclear waste

Abstract

A laboratory standard for the determination of long-lived radionuclides 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-grained ready-to-use cement mixture, to which the following radionuclides were added:⁶⁰Co and¹³⁷Cs as γ-ray-emitting nuclides,⁹⁹Tc,⁹⁰Sr and⁵⁵Fe as radionuclides emitting pure β-radiation or low-energy electrons, and²³³U,²³⁷Np,²³⁸Pu and²⁴¹Am as α-emitters. Care was taken to attain a homogeneous distribution of the nuclides in the standard material. Pieces of about 1 g were formed as suitable and representative samples. Repeated analyses were carried out with the standard to check its homogeneity. The analytical procedures are described in brief. The pieces of the standard material have the same content of nuclides within ±5% at a 95% level of confidence.