A container holds radioactive material. A sub-criticality controller protects the radioactive material from reaching a criticality from contact with the water. The sub-criticality controller includes a metallic composition having at least one metal component and at least one borate component bonded to the at least one metal component. The metallic composition forms borates from the borate component when the metallic composition contacts the water.

A container holds radioactive material. A sub-criticality controller protects the radioactive material from reaching a criticality from contact with the water. The sub-criticality controller includes a metallic composition having at least one metal component and at least one borate component bonded to the at least one metal component. The metallic composition forms borates from the borate component when the metallic composition contacts the water.

Methods for storing or disposing of nuclear waste include forming a drillhole that extends into the Earth from a terranean surface. The drillhole includes an entry at least proximate the terranean surface, a substantially vertical drillhole portion, and a hazardous material storage drillhole portion that is coupled to the substantially vertical drillhole portion and is formed in a subterranean salt formation. The methods further include moving a storage canister into the hazardous material storage drillhole portion. The storage canister is 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 has an inner cavity that encloses nuclear waste material. The methods further include positioning a seal in the drillhole to isolate the hazardous material storage drillhole portion of the drillhole from the entry of the drillhole.

Methods for storing or disposing of nuclear waste include forming a drillhole that extends into the Earth from a terranean surface. The drillhole includes an entry at least proximate the terranean surface, a substantially vertical drillhole portion, and a hazardous material storage drillhole portion that is coupled to the substantially vertical drillhole portion and is formed in a subterranean salt formation. The methods further include moving a storage canister into the hazardous material storage drillhole portion. The storage canister is 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 has an inner cavity that encloses nuclear waste material. The methods further include positioning a seal in the drillhole to isolate the hazardous material storage drillhole portion of the drillhole from the entry of the drillhole.

A composite panel for a toxic material encapsulation system, comprising a reinforcing structure extending within and integrally formed with a non-biodegradable thermoplastic polymer.

A composite panel for a toxic material encapsulation system, comprising a reinforcing structure extending within and integrally formed with a non-biodegradable thermoplastic polymer.

An underground ventilated system for storing nuclear waste materials. The system includes a storage module having an outer shell defining an internal cavity and an inner shell. A majority of the height of the outer shell may be disposed below grade. The outer shell may include a hermetically sealed bottom. First and second canisters are positioned in lower and upper portions within the cavity respectively in vertically stacked relationship. A centering and spacing ring assembly is interspersed between the first and second canisters to transfer the weight of the upper second canister to the lower first canister. The assembly may include centering lugs which laterally restrain the first and second canisters in case of a seismic event. A natural convection driven ventilated air system cools the canisters to remove residual decay heat to the atmosphere. In one non-limiting embodiment, the shells are made of steel.

An underground ventilated system for storing nuclear waste materials. The system includes a storage module having an outer shell defining an internal cavity and an inner shell. A majority of the height of the outer shell may be disposed below grade. The outer shell may include a hermetically sealed bottom. First and second canisters are positioned in lower and upper portions within the cavity respectively in vertically stacked relationship. A centering and spacing ring assembly is interspersed between the first and second canisters to transfer the weight of the upper second canister to the lower first canister. The assembly may include centering lugs which laterally restrain the first and second canisters in case of a seismic event. A natural convection driven ventilated air system cools the canisters to remove residual decay heat to the atmosphere. In one non-limiting embodiment, the shells are made of steel.

Open pit mine (OPM) structures are modified or built new for use in disposing of low-level radioactive/nuclear waste (LLW). A drainage system is added to the OPM to drain water, such as, but not limited to, rain water, out of a volume of the OPM and to a particular geologic zone located far below the OPM that is isolated away from the local water table. Cells are formed within the volume of the OPM that are configured to receive the LLW. Cells are added to the OPM from a bottom towards a top of the OPM. Void spaces around the LLW materials within the cells are filled in with a protective-medium to mitigate against radionuclide migration away from the LLW materials within the cells. The protective-medium may be a blend of carbon nanotubes and a foam cement slurry. The carbon nanotubes may be made from reacting ethylene with vermiculite.

Open pit mine (OPM) structures are modified or built new for use in disposing of low-level radioactive/nuclear waste (LLW). A drainage system is added to the OPM to drain water, such as, but not limited to, rain water, out of a volume of the OPM and to a particular geologic zone located far below the OPM that is isolated away from the local water table. Cells are formed within the volume of the OPM that are configured to receive the LLW. Cells are added to the OPM from a bottom towards a top of the OPM. Void spaces around the LLW materials within the cells are filled in with a protective-medium to mitigate against radionuclide migration away from the LLW materials within the cells. The protective-medium may be a blend of carbon nanotubes and a foam cement slurry. The carbon nanotubes may be made from reacting ethylene with vermiculite.