Study of thermomechanical treatment for manufacturing UAlx/Al dispersion targets

Abstract

Uranium aluminide/aluminum (UAlx-Al) targets are widely used in research reactors to produce 99Mo radioisotopes as a fission product of 235U. The 99Mo decays into 99mTc, which is the most suitable radionuclide for single-photon emission computed tomography image technique. The UAlx-Al targets were fabricated according to the picture frame technique, which employs hot rolling of such dispersion. The UAl2 is the starting uranium compound used as fissile material in the dispersion. During the manufacturing of targets some solid state reactions take place between UAl2 and Al matrix producing UAl3 and UAl4. The specification claims that the finished target must be free of UAl2 in its composition, because UAl2 is harder to dissolve in radiochemical processing. This work aims to develop a thermomechanical treatment that can consume all UAl2 initially presented in the dispersion. The dilatometry and x-ray diffraction with Rietveld refinement were used to obtain a final optimized thermomechanical treatment for the UAlx/Al dispersion targets.