Patent Number: 
Section: claims

1. A hazardous material storage repository, comprising:a drillhole that extends into the Earth from a terranean surface, the drillhole comprising an entry at least proximate the terranean surface, the drillhole comprising a substantially vertical drillhole portion and a hazardous material storage drillhole portion that is coupled to the substantially vertical drillhole portion and formed in a subterranean salt formation;a storage canister positioned in the hazardous material storage drillhole portion, the storage canister sized to fit from the drillhole entry through the substantially vertical drillhole portion, and into the hazardous material storage drillhole portion of the drillhole, the storage canister comprising an inner cavity sized to enclose nuclear waste material; anda seal positioned in the drillhole, the seal isolating the hazardous material storage drillhole portion of the drillhole from the entry of the drillhole. 2. The hazardous material storage repository of claim 1, wherein the nuclear waste material comprises plutonium. 3. The hazardous material storage repository of claim 1, wherein the subterranean salt formation comprises an impermeable formation layer. 4. The hazardous material storage repository of claim 3, wherein the impermeable formation layer is vertically isolated from a subterranean formation that comprises mobile water. 5. The hazardous material storage repository of claim 1, wherein the drillhole further comprises a substantially non-vertical drillhole portion. 6. The hazardous material storage repository of claim 5, wherein at least a portion of the substantially non-vertical drillhole portion comprises the hazardous material storage drillhole portion. 7. The hazardous material storage repository of claim 1, further comprising:a casing installed in at least a portion of the drillhole; anda cement layer installed adjacent the casing. 8. The hazardous material storage repository of claim 7, wherein the casing is installed in at least a portion of the substantially vertical drillhole portion. 9. The hazardous material storage repository of claim 1, wherein the seal is positioned in the substantially vertical drillhole portion. 10. The hazardous material storage repository of claim 1, wherein the storage canister comprises a first storage canister, the repository further comprising:a second storage canister positioned in the hazardous material storage drillhole portion adjacent the first storage canister, the second storage canister sized to fit from the drillhole entry through the substantially vertical drillhole portion, and into the hazardous material storage drillhole portion of the drillhole, the second storage canister comprising an inner cavity sized to enclose nuclear waste material. 11. The hazardous material storage repository of claim 1, wherein the nuclear waste material comprises military nuclear waste material. 12. The hazardous material storage repository of claim 11, wherein the subterranean salt formation comprises an impermeable formation layer. 13. The hazardous material storage repository of claim 12, wherein the impermeable formation layer is vertically isolated from a subterranean formation that comprises mobile water. 14. The hazardous material storage repository of claim 11, wherein the drillhole further comprises a substantially non-vertical drillhole portion. 15. The hazardous material storage repository of claim 14, wherein at least a portion of the substantially non-vertical drillhole portion comprises the hazardous material storage drillhole portion. 16. The hazardous material storage repository of claim 8, wherein the nuclear waste material comprises military nuclear waste material. 17. The hazardous material storage repository of claim 16, wherein the storage canister comprises a first storage canister, the repository further comprising:a second storage canister positioned in the hazardous material storage drillhole portion adjacent the first storage canister, the second storage canister sized to fit from the drillhole entry through the substantially vertical drillhole portion, and into the hazardous material storage drillhole portion of the drillhole, the second storage canister comprising an inner cavity sized to enclose military nuclear waste material. 18. The hazardous material storage repository of claim 11, further comprising:a casing installed in at least a portion of the drillhole; anda cement layer installed adjacent the casing. 19. The hazardous material storage repository of claim 18, wherein the subterranean salt formation comprises an impermeable formation layer, and the impermeable formation layer is vertically isolated from a subterranean formation that comprises mobile water. 20. The hazardous material storage repository of claim 19, wherein the drillhole further comprises a substantially non-vertical drillhole portion, and at least a portion of the substantially non-vertical drillhole portion comprises the hazardous material storage drillhole portion.