In-line determination of heavy elements by gamma ray-induced energy-dispersive K-line XRF

In-line determination of heavy elements, especially in nuclear fuel reprocessing solutions by means of XRF analysis and -emitting radionuclides as excitation sources for the K-lines has been investigated.⁵⁷Co,¹³³Ba and¹⁹²Ir are used as radionuclide sources. U, Np, and Pu can be determined from the lower ppm range up to the saturation concentration of about 400 g/l. In case of Pu concentrations >100 mg/l the detection limits for U and Np increase. A matrix effect due to the composition of the solution is observed, which depends only on the density of the solution. At higher activities of fission products in the solution, an increase of the background count rate but no interferences are observed. This allows determination of heavy elements in fission product solutions.