Nondestructive Assay of Plutonium and Uranium in Mixed-Oxides

Nondestructive assay measurements were performed on mixed-oxide fuel samples with the objective of determining their Pu and U content. A total of nine mixed-oxide samples were measured, in addition to a separate set of calibration standards. The measurements were performed with a Rad Tech Isotopic Source Assay System (ISAS), which directly counts fission events by utilizing the fact that fission is characterized by a high multiplicity of particles, 7 gammas and 2.5 neutrons, on the average, simultaneously emitted in each fission event. ISAS utilizes coincidence counting techniques for the assay of fissionable materials (Ref. 1).