Patent Number: 
Section: claims

1. A nuclear waste canister, comprising:a housing that at least partially defines an inner volume sized to enclose a plurality of nuclear waste portions and configured to store the nuclear waste portions in a hazardous waste repository of a directional drillhole formed in a subterranean formation;a solid or semi-solid granular material enclosed in the inner volume of the housing that at least substantially fills voids within the inner volume and between the plurality of nuclear waste portions; anda friction brake mounted to an end of the housing. 2. The nuclear waste canister of claim 1, wherein the nuclear waste portions comprise a plurality of spent nuclear fuel (SNF) rods of an SNF assembly. 3. The nuclear waste canister of claim 2, wherein the inner volume is sized to store a single SNF assembly. 4. The nuclear waste canister of claim 1, wherein the solid or semi-solid granular material comprises a solid powder. 5. The nuclear waste canister of claim 4, wherein the solid powder comprises silicon-dioxide. 6. The nuclear waste canister of claim 1, wherein the solid or semi-solid granular material comprises a neutron-absorbing material. 7. The nuclear waste canister of claim 1, further comprising an impact absorber positioned within the inner volume or on an exterior surface of the housing. 8. The nuclear waste canister of claim 7, wherein the impact absorber comprises a crushable member or spring member. 9. The nuclear waste canister of claim 7, wherein the impact absorber comprises a corrosion-resistant material. 10. The nuclear waste canister of claim 1, wherein the friction brake is mounted to the housing with a pivotable or rotatable connection. 11. The nuclear waste canister of claim 1, wherein the end of the housing comprises a downhole end of the housing. 12. The nuclear waste canister of claim 1, wherein the friction brake comprises a surface configured to contact a casing installed in the directional drillhole. 13. A method for storing nuclear waste, comprising:placing a plurality of nuclear waste portions into an inner volume of a housing of a nuclear waste canister configured to store the nuclear waste portions in a hazardous waste repository of a directional drillhole formed in a subterranean formation, wherein the nuclear waste canister comprises a friction brake mounted to an end of the housing;substantially filling voids within the inner volume and between the plurality of nuclear waste portions with a solid or semi-solid granular material; andsealing the inner volume of the nuclear waste canister to enclose the plurality of nuclear waste portions and the solid or semi-solid granular material. 14. The method of claim 13, wherein the nuclear waste portions comprise a plurality of spent nuclear fuel (SNF) rods of an SNF assembly. 15. The method of claim 14, wherein the inner volume is sized to store a single SNF assembly. 16. The method of claim 13, wherein the solid or semi-solid granular material comprises a solid powder. 17. The method of claim 16, wherein the solid powder comprises silicon-dioxide. 18. The method of claim 13, wherein the solid or semi-solid granular material comprises a neutron-absorbing material. 19. The method of claim 13, wherein the nuclear waste canister further comprises an impact absorber positioned within the inner volume or on an exterior surface of the housing. 20. The method of claim 19, wherein the impact absorber comprises a crushable member or spring member. 21. The method of claim 19, wherein the impact absorber comprises a corrosion-resistant material. 22. The method of claim 13, wherein the friction brake is mounted to the housing with a pivotable or rotatable connection. 23. The method of claim 13, wherein the end of the housing comprises a downhole end of the housing. 24. The method of claim 13, wherein the friction brake comprises a surface configured to contact a casing installed in the directional drillhole. 25. The method of claim 13, further comprising moving the sealed nuclear waste canister into the hazardous waste repository of the directional drillhole. 26. The method of claim 25, further comprising mitigating an impact of the sealed nuclear waste canister during a free fall event during movement of the sealed nuclear waste canister through the directional drillhole. 27. The method of claim 26, wherein mitigating the impact of the sealed nuclear waste canister during the free fall event during movement of the sealed nuclear waste canister through the directional drillhole comprises contacting a portion of the directional drillhole or a wellbore fluid with the friction brake during the free fall event. 28. The method of claim 27, wherein contacting the portion of the directional drillhole or the wellbore fluid with the friction brake during the free fall event comprises contacting a casing positioned in the directional drillhole with the friction brake during the free fall event.