There are three uranium carbide compounds (UC, U2C3, and U2C) with the great­est interest in UC. UC is often considered the ideal nuclear fuel compared to the metallic uranium and UO2 fuels. UC does not undergo phase change until its melt­ing point (2350 ° C) and has a high uranium density and also a higher thermal con­ductivity than UO2. UC also shows good thermal and irradiation stability (fission gas release and swelling are moderate and little cracking is observed). The higher

uranium atom density and higher thermal conductivity can result into the following:

i) Larger size of fuel elements desired for an economic fuel fabrication.

ii) Higher power density or specific power attainable.

iii) Smaller primary components such as pressure vessel, piping system, and so on.

7.3.3