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.

Techniques for determining the suitability of a subterranean formation as a hazardous waste repository include determining a neutron flux of a first isotope in a subterranean formation; calculating, based at least in part on the determined neutron flux of the first isotope, a predicted production rate of a second isotope in the subterranean formation; calculating a first ratio of the predicted production rate of the second isotope relative to a theoretical production rate of a stable form of the second isotope; measuring respective concentrations of the second isotope and the stable form of the second isotope in a subterranean water sample; calculating a second ratio of the measured concentration of the second isotope relative to the measured concentration of the stable form of the second isotope; and based on a comparison of the first and second ratios, determining that the subterranean formation is suitable as a hazardous waste repository.

Treatment technology directed to using mine waste as a raw material to manufacture a mine filling product for use as a suitable precursor product or mine filling product to be used as a backfill material to close a mine. The precursor product or mine filling product retains its metals and is not be able to generate acidity. According to the disclosure, the precursor product or mine filling product, when placed in a mine, may also remove metals from mine fluids in the mine it contacts, and still retain the metals it hosted when it was a mine waste prior to it being used as a raw material to manufacture the precursor stowing backfill product.

Techniques for determining the suitability of a subterranean formation as a hazardous waste repository include determining a neutron flux of a first isotope in a subterranean formation; calculating, based at least in part on the determined neutron flux of the first isotope, a predicted production rate of a second isotope in the subterranean formation; calculating a first ratio of the predicted production rate of the second isotope relative to a theoretical production rate of a stable form of the second isotope; measuring respective concentrations of the second isotope and the stable form of the second isotope in a subterranean water sample; calculating a second ratio of the measured concentration of the second isotope relative to the measured concentration of the stable form of the second isotope; and based on a comparison of the first and second ratios, determining that the subterranean formation is suitable as a hazardous waste repository.

Techniques for determining the suitability of a subterranean formation as a hazardous waste repository include determining a concentration of at least one noble gas isotope of a plurality of noble gas isotopes in fluid sample from a subterranean formation below a terranean surface; determining a produced amount of the at least one noble gas isotope in the subterranean formation based on a production rate of the at least one noble gas isotope and a minimum residence time; calculating a ratio of the determined concentration of the at least one noble gas isotope in the fluid sample to the determined produced amount of the at least one noble gas isotope; and based on the calculated ratio being at or near a threshold value, determining that the subterranean formation is suitable as a hazardous waste repository.

Systems and/or methods of waste disposal use human-made caverns that are constructed within deep geological formations. A given human-made cavern may be constructed by first drilling out a vertical wellbore to a deep geological formation. Then a bottom portion of the vertical wellbore is jet drilled using an abrasive jetting fluid to form a launch chamber of void volume, that is sized to fit a reaming tool in its deployed open configuration. A reaming tool, in a closed configuration, is then inserted into the vertical wellbore for landing in the launch chamber. The reaming tool is then deployed into its open configuration while in the launch chamber. Reaming operations then occur from the launch chamber directed downwards within the deep geological formation, forming a given human-made cavern. The newly formed human-made cavern may be conditioned and/or configured for receiving amounts of the waste for long-term disposal and/or storage.

Techniques for storing nuclear waste include 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; substantially filling voids within the inner volume and between the plurality of nuclear waste portions with a solid or semi-solid granular material; and sealing the inner volume of the nuclear waste canister to enclose the plurality of nuclear waste portions and the solid or semi-solid granular material.

A drillhole plug includes a frame or housing of a corrosion-resistant material and sized to fit within a milled portion of a directional drillhole that includes a hazardous waste repository; and a material that fills at least a portion of the frame or housing. The material exhibits creep such that the material fills one or more voids between the frame or housing and a subterranean formation adjacent the milled portion of the directional drillhole.

Techniques for storing nuclear waste hazardous material include identifying a storage area of a directional wellbore formed from a terranean surface and extending into a subterranean formation; circulating a slurry that includes a hardenable material and one or more portions of nuclear waste hazardous material into the storage area; forming a seal in the directional wellbore that isolates the storage area of the directional wellbore from an entry of the directional wellbore; monitoring at least one variable associated with the one or more portions of nuclear waste hazardous material from a sensor positioned proximate the storage area; recording the monitored variable at the terranean surface; and based on the monitored variable exceeding a threshold value, removing the seal from the wellbore and retrieving at least a portion of the slurry from the storage area to the terranean surface.

Systems and methods for long-term disposal of radioactive or nuclear waste materials, in liquid, solid, and/or other physical forms, into human-made caverns, within deep geologic rock formations, derived from a wellbore, are manufactured by use of drilling and reaming technologies. The radioactive waste may be preprocessed from original surface storage site(s), transported, temporarily surface stored, and then finally further processed at a selected well site before injection into the subterranean deep human-made caverns within the host rock (deep geologic rock formations).