Hot Impact Densification: A New Method for Producing High Density Ceramic Pellets with Close Shape Tolerances

Density and correct diameter of nuclear fuel pellets are usually achieved by sintering and subsequent circular grinding. Hot impact densification (HID) thermally squatted ceramic bodies can be directly high speed precision-molded in a cold die. For thermoshock-sensitive materials, a controlled cooling down procedure of some minutes is added. The feasibility of HID has been demonstrated on the laboratory scale on UO₂, UC, and some more materials at temperatures between 1700 and 2300°C, pressures up to 800 N/mm². Shape tolerances are close, density can be exactly reproduced within a wide range. Tool wear seems to be no problem. Currently, a prototype facility for continuous performance is being developed.