Patent Number: 
Section: claims

1. A composition comprising LiF, UF4, ThF4, and PuF3, wherein the UF4 and ThF4 are together present in a mole fraction of from about 20 to about 30% of the composition, and wherein the composition is molten at a temperature of between about 475° C. and about 575° C. 2. The composition of claim 1, wherein the LiF is present in a mole fraction of from about 70 to about 80% of the composition. 3. The composition of claim 1, wherein the LiF is present in a mole fraction of from about 72 to about 77% of the composition. 4. The composition of claim 1, wherein the LiF is present in a mole fraction of about 74.5% of the composition. 5. The composition of claim 1, wherein the UF4 is present in a mole fraction of from about 0.1 to about 24% of the composition. 6. The composition of claim 1, wherein the UF4 is present in a mole fraction of from about 6 to about 12% of the composition. 7. The composition of claim 1, wherein the UF4 is present in a mole fraction of about 9% of the composition. 8. The composition of claim 1, wherein the ThF4 is present in a mole fraction of from about 0.1 to about 24% of the composition. 9. The composition of claim 1, wherein the ThF4 is present in a mole fraction of from about 12 to about 18% of the composition. 10. The composition of claim 1, wherein the ThF4 is present in a mole fraction of about 15% of the composition. 11. The composition of claim 1, wherein the UF4 and ThF4 are together present in a mole fraction of from about 22 to about 26% of the composition. 12. The composition of claim 1, wherein the UF4 and ThF4 are together present in a mole fraction of about 24% of the composition. 13. The composition of claim 1, wherein the PuF3 is present in a mole fraction of from about 0.1 to about 5% of the composition. 14. The composition of claim 1, wherein the PuF3 is present in a mole fraction of from about 1 to about 2% of the composition. 15. The composition of claim 1, wherein the composition is molten at a temperature of between about 500° C. and about 550° C. 16. The composition of claim 1, wherein the composition is molten at a temperature of about 520° C. 17. The composition of claim 1, whereinthe LiF is present in a mole fraction of about 74.5% of the composition;the UF4 is present in a mole fraction of about 9% of the composition;the ThF4 is present in a mole fraction of about 15% of the composition; andthe PuF3 is present in a mole fraction of about 1.5% of the composition, wherein the composition is molten at a temperature of about 520° C.