Determination of the alloying content in the matrix of Zr alloys using synchrotron radiation microprobe X-ray fluorescence

The alloying element content in the α-Zr matrix of Zr alloys was studied using synchrotron radiation microprobe X-ray fluorescence, coupled with Monte Carlo simulation of the fluorescence process for quantification of the concentrations. The agreement between the measured values and the bulk concentrations of the alloy standards, as measured by the overall fit of the full fluorescence spectrum, was excellent. We measured the concentration of insoluble alloying elements in the matrix of Zircaloy-4 previously annealed to 705 °C for 125 h (corresponding to a cumulative annealing parameter (CAP) of 2.1 × 10−16 h, CAP=∑itiexp(−Q/RTi) where ti is the time (hours) spent at temperature Ti (K) and Q/R=40 000 K) and in the matrix of a ZrSnNbFe alloy with a composition similar to ZIRLOTM, but annealed at 710 °C for 92 h. The matrix concentrations of alloying elements were found to be, Fe=290 wt. ppm, Cr=270 wt. ppm in Zircaloy-4 and Fe=250 wt. ppm in the ZrSnNbFe alloy. These results are discussed in light of other experimental determinations of alloying element concentrations in the literature.