Method of manufacturing a nuclear fuel element end plug which contains ß-SiC, Al2O3, and Y2O3

A method for manufacturing an end plug for sealing a composite tubular ceramic cladding of a fuel element of a nuclear reactor, comprising the steps of:

• preparing a powder mixture from β-SiC powder, Al2O3 powder and Y2O3 powder, which are taken in the following quantities, wt %:
• β-SiC with particles of 0.95 microns—10.59,
• β-SiC with particles of 5.19 microns—77.91,
• Al2O3 with particles of 1.52 microns—10.0,
• Y2O3 with particles of 1.01 microns—the rest;
• hot pressing of the powder mixture with the use of upper and lower punches and a mold with mold cells,
• wherein each mold cell has a shape and dimensions corresponding to an end plug having a first part and a second part,
• wherein the first and second parts are coaxial cylinders having different diameters,
• wherein the step of hot pressing comprises the steps of:
• arranging the lower punches into inner cavities of the mold cells,
• loading the powder mixture into the inner cavities and onto the lower punches,
• putting the upper punches into the mold cells over the powder mixture,
• holding the powder mixture without heating at the pressure of 1 Pa for more than 12 hours,
• pressing the powder mixture in the mold cells with the use of the upper punches,
• sintering at the temperature of 1850 degrees C. in an inert gas atmosphere or in vacuum at the pressure of 0.1 MPa, and
• having the holding duration in the sintering mode be 120 minutes;
• and
• ejecting finished end plugs from the mold cells.