The on-line characterization of a radium slurry by γ-ray spectrometry

We have developed an in-line monitor to directly measure the 226Ra concentration in a nuclear waste stream using quantitative gamma-ray spectrometry applied to the 186 keV emission. The waste stream is in the form of a slurry composed of the solid waste material mixed with water. The concentration measurement includes a self-attenuation correction factor determined from a transmission measurement using the 122 keV γ from 57Co. Presented here is the model for the measurement system and results from some initial tests.