Method of making a nuclear fuel pellet for a nuclear power reactor

A method of making a nuclear fuel pellet for a nuclear power reactor, the method comprising the following steps:

• providing a nuclear fuel material in powder form,
• providing an additive,
• pressing the powder such that a green pellet is obtained,
• wherein said additive is added either to said nuclear fuel material in powder form or to the green pellet,
• sintering the so obtained green pellet,
• wherein said additive is such that larger grains in the nuclear fuel material are present in the pellet after the sintering step as compared with the grain size obtained if a pellet, which is produced according to the above manner but without the addition of the additive, is sintered in the same manner,
• wherein said additive is made of or includes a substance which causes said larger grains in the sintered pellet, wherein said substance is selected and the method is performed such that at least to 90% of the substance, leaves at least an outer portion of the pellet before and/or during the sintering step.