Patent Number: 
Section: claims

1. A nuclear fuel product comprising:fragile fuel particles that include a fuel kernel and one or more layers encapsulated within a zirconium carbide (ZrC) matrix,wherein the zirconium carbide matrix includes near fully dense ZrC that is sub-stoichiometric ZrC between 93% theoretical density and less than 100% theoretical density. 2. The nuclear fuel product of claim 1, wherein the fragile fuel particles include Tri Structural Isotropic fuel (TRISO) fuel particles or a variation of TRISO fuel particles utilizing zirconium carbide (TRIZO). 3. The nuclear fuel product of claim 1, wherein the fragile fuel particles include Bi Structural Isotropic fuel (BISO) fuel particles. 4. A method of fabricating the nuclear fuel product of claim 1, comprising:utilizing a non-stoichiometric reaction of ZrC, zirconium hydride (ZrH), and free carbon (C), wherein the ZrC is 0-10 mass percent and the free carbon is 0-4 mass percent. 5. A nuclear thermal propulsion system, comprising:the nuclear fuel product of claim 1. 6. A nuclear reactor, comprising:the nuclear fuel product of claim 1. 7. A method of fabricating the nuclear fuel product of claim 1, comprising:creating a transient eutectic phase (TEP) silicon carbide (SiC) mixture that includes an SiC powder and an oxide power of at least one sintering aid to suppress a processing temperature for sintering of ZrC. 8. The method of fabricating the nuclear fuel product of claim 7, further comprising:prior to creating the TEP SiC mixture, implementing a chemical vapor deposition process to form the SiC powder as a 35 nanometer (nm) to 85 nm nanophase powder. 9. The method of fabricating the nuclear fuel product of claim 7, wherein the TEP SiC mixture includes approximately 94% SiC, 3.9% aluminum oxide (Al2O3), and 2.1% yttrium oxide (Y2O3) by mass. 10. The method of fabricating the nuclear fuel product of claim 7, further comprising:mixing a ZrC powder with the TEP SiC mixture to form a ZrC-TEP SiC mixture. 11. The method of fabricating the nuclear fuel product of claim 10, wherein the mixing the ZrC powder with the TEP SiC mixture to form the ZrC-TEP SiC mixture includes:adding the TEP SiC mixture to the ZrC powder; andkinetic milling and high-shear milling to combine the ZrC powder with the TEP SiC mixture. 12. The method of fabricating the nuclear fuel product of claim 10, wherein the mixing the ZrC powder with the TEP SiC mixture is in a ratio of 10 wt % TEP SiC mixture. 13. The method of fabricating the nuclear fuel product of claim 10, further comprising:adding the fragile fuel particles to the ZrC-TEP SiC mixture;loading the ZrC-TEP SiC mixture with the added fragile fuel particles into a die; andcompacting the ZrC-TEP SiC mixture and the fragile fuel particles by spark plasma sintering. 14. The method of fabricating the nuclear fuel product of claim 13, wherein the spark plasma sintering is at a processing pressure of less than or equal to 20 megapascals (MPa) and the suppressed processing temperature is less than or equal to 2,000 degrees Celsius. 15. The method of fabricating the nuclear fuel product of claim 13, wherein after the spark plasma sintering:the zirconium carbide matrix surrounds the fragile fuel particles; andthe fragile fuel particles are unbroken and are intimately bonded with the zirconium carbide matrix. 16. A method of fabricating the nuclear fuel product of claim 1, comprising:creating a non-stoichiometric mixture that includes a ZrC powder, a carbon (C) powder, and zirconium hydride (ZrH) to suppress a processing temperature for sintering of ZrC. 17. The method of fabricating the nuclear fuel product of claim 16, further comprising:adding the fragile fuel particles to the non-stoichiometric mixture; andsintering the non-stoichiometric mixture and the fragile fuel particles. 18. The method of fabricating the nuclear fuel product of claim 17, wherein the sintering the non-stoichiometric mixture and the fragile fuel particles includes:decomposing the hydride of the ZrH at approximately 900 degrees Celsius during the sintering to achieve a processing pressure of less than or equal to 20 megapascals (MPa) and the suppressed processing temperature between 1,650-1,800 degrees Celsius. 19. The method of fabricating the nuclear fuel product of claim 16, wherein the non-stoichiometric mixture includes the ZrH up to 10 weight percent by mass and the carbon between 0.1 to 4 weight percent by mass.