Ceramic Plasma-Spray-Coated Graphite Crucible For Injection Casting Of Fast Reactor Fuel Slugs

Ceramic plasma-spray coatings with single and multiple layers have been applied to melting crucible material substrates for the development of a reusable crucible for the fabrication of metal fuel slugs for a sodium-cooled fast reactor (SFR). Various combinations of vacuum plasma-spray (VPS) coated specimens have been applied to investigate the bonding effect on the crucible substrate and the interaction between the metal fuel and the VPS-coated crucible substrate. All VPS-coated methods maintained a sound coating state after a dipping test with U-10wt%Zr melt. A single coating of a Y2O3(150) layer and a double coating layer of TaC(50)-Y2O3(100) showed some degradation or penetration, respectively, after 2 cycles of dipping test with an aggressive U-10wt%Zr-5wt%RE melt. Injection castings of U-10wt%Zr and U-10wt%Zr-5wt%RE fuel slugs were also conducted to investigate the feasibility of a reusable melting crucible of metal fuel slugs. The U-10wt%Zr fuel slugs were soundly fabricated without significant interactions of the graphite crucibles; however, the U-10wt%Zr-5wt%RE fuel slugs had some degradation or penetration, respectively, after injection casting.