Patent Number: 
Section: claims

1. A metal fuel system comprising:particulate metal fuel for use in nuclear reactors, comprising particles of at least one enriched alloy and particles of crushed light water reactor (LWR) spent nuclear fuel;a cladding;a gas-filled plenum; andwherein the particles are compacted into a fuel column, and wherein the fuel column is in particulate form, not solid form, upon entry into a reactor. 2. The metal fuel system of claim 1, wherein the compaction is obtained by vibration or another impaction technique. 3. The metal fuel system of claim 1, wherein the at least one enriched alloy is selected from the group consisting of: uranium, plutonium, transuranics, zirconium, molybdenum, actinides, and combinations thereof. 4. The metal fuel system of claim 1, wherein the particulate metal fuel further comprises minor actinides. 5. The metal fuel system of claim 1, further comprising a gaseous heat transfer medium in the cladding. 6. The metal fuel system of claim 5, wherein the gaseous heat transfer medium is helium gas. 7. The metal fuel system of claim 1, wherein the smear density of the fuel column is approximately 75% or less. 8. The metal fuel system of claim 1, wherein a volume ratio of particulate metal fuel to plenum is approximately 0.8 to approximately 2.0. 9. The metal fuel system of claim 1, further comprising a restrainer to maintain pressure on the fuel column. 10. The metal fuel system of claim 1, wherein the particles are between about 50 and about 1000 microns in diameter. 11. The metal fuel system of claim 1, wherein the particulate metal fuel comprises approximately 8-10% crushed light water reactor (LWR) particles. 12. A metal fuel system comprising:particulate metal fuel for use in nuclear reactors, comprising particles of at least one enriched alloy, wherein the particulate metal fuel further comprises minor actinides;a cladding;a gas-filled plenum; andwherein the particles are compacted into a fuel column, and wherein the fuel column is in particulate form, not solid form, upon entry into a reactor. 13. The metal fuel system of claim 12, wherein the minor actinides are selected from the group consisting of: americium, neptunium, curium, and combinations thereof. 14. The metal fuel system of claim 12, wherein the particulate metal fuel further comprises crushed light water reactor (LWR) particles. 15. The metal fuel system of claim 14, wherein the particulate metal fuel comprises approximately 8-10% crushed light water reactor (LWR) particles. 16. The metal fuel system of claim 12, wherein the at least one enriched alloy is selected from the group consisting of: uranium, plutonium, transuranics, zirconium, molybdenum, actinides, and combinations thereof. 17. The metal fuel system of claim 12, wherein the particles are between about 50 and about 1000 microns in diameter. 18. A metal fuel system comprising:particulate metal fuel for use in nuclear reactors, comprising particles of at least one enriched alloy and particles of crushed light water reactor (LWR) spent nuclear fuel, wherein the particulate metal fuel further comprises minor actinides;a cladding;a gas-filled plenum; andwherein the particles are compacted into a fuel column, and wherein the fuel column is in particulate form, not solid form, upon entry into a reactor. 19. The metal fuel system of claim 18, wherein the minor actinides are selected from the group consisting of: americium, neptunium, curium, and combinations thereof. 20. The metal fuel system of claim 18, wherein the particulate metal fuel comprises approximately 8-10% crushed light water reactor (LWR) particles. 21. The metal fuel system of claim 18, wherein the at least one enriched alloy is selected from the group consisting of: uranium, plutonium, transuranics, zirconium, molybdenum, actinides, and combinations thereof. 22. The metal fuel system of claim 21, wherein the at least one enriched alloy is uranium.