Plutonium-based ceramic compounds are mainly plutonium dioxide (PuO2), pluto­nium monocarbide (PuC), and plutonium nitride (PuN). But they are generally used with UO2, UC, and UN, respectively, in the form of mixed oxide fuels. These are considered fast breeder reactor fuels. Mixed oxide fuels have drawn the most interest because of the long experience with them. The physical, mechanical, and chemical properties of UO2 and PuO2 are quite comparable. The nuclear properties of ceramic plutonium fuels are considered better than ceramic uranium fuels. However, plutonium fuels must be diluted. Mixed ceramic uranium-plutonium fuels have certain benefits: (i) high melting temperatures, (ii) well-developed fuel fabrication technology and operation experience (obtained from UO2 fuel), and (iii) good thermal and irradiation stability. Given the lack of their near-term appli­cation as nuclear fuels, we will not discuss this further. Readers should refer to appropriate literature to gain information in this area.

7.3.5