Sinterability of ZrN and (Zr_0.6Dy_0.4)N pellets - surrogate fuel fabrication for ELECTRA

Pellets of inert matrix material ZrN and surrogate nitride fuel material (Zr_0.6Dy_0.4)N are fabricated for the purpose of investigating the origin and the effect of C and O impurity concentrations. Oxygen concentrations of up to 1.5 wt% were deliberately introduced to the materials with two separate methods. The achievable green and sintered pellet densities of these materials as a function of O content, dimensional properties of the powder and sintering temperature are shown. The effect of O dissolved into the matrix vs oxide-rich phase segregation is discussed. Oxygen pickup during the fabrication of the product as well as its exposure to air is demonstrated. The quality of the materials is monitored by the systematic analysis of O, N and C contents throughout the fabrication and sintering processes, supported by XRD and SEM analyses. (author)