Systems and methods for controlling extraction of landfill gas from a landfill via a gas extraction system are provided herein. According to some aspects of the technology, there is provided site-level control methods for globally controlling one or more wells based on one or more characteristics of aggregate landfill gas collected from a plurality of wells at a gas output. According to some aspects of the technology, there is provided well-level control methods for locally controlling a first well based on or more characteristics of landfill gas collected from the first well. According to further aspects of the technology, there is provided hybrid control methods for making adjustments to a respective well based on both site-level and well-level control methods.

Systems and methods for controlling extraction of landfill gas from a landfill via a gas extraction system are provided herein. According to some aspects of the technology, there is provided site-level control methods for globally controlling one or more wells based on one or more characteristics of aggregate landfill gas collected from a plurality of wells at a gas output. According to some aspects of the technology, there is provided well-level control methods for locally controlling a first well based on or more characteristics of landfill gas collected from the first well. According to further aspects of the technology, there is provided hybrid control methods for making adjustments to a respective well based on both site-level and well-level control methods.

An apparatus for sampling landfill gas from a landfill flowing through a pipe. The apparatus may comprise: an enclosure configured to receive a section of the pipe; a gas sampling port in the section of the pipe; at least one sensor device disposed in a region of the enclosure, the at least one sensor being coupled to the section of the pipe through the gas sampling port; and thermal insulation positioned to retain heat from the section of the pipe in the region of the enclosure. A method of operating a landfill gas recovery system. The method may comprise: flowing gas from a well riser pipe through a sampling subsystem to a collection system; and heating a portion of the sampling subsystem with the gas flowing from the well riser pipe to the collection system.

A system for extracting landfill gas from a landfill is provided. According to some embodiments, a control system for landfill gas extraction is provided. The control system uses a throttle to control flow of landfill gas extracted from the landfill. The throttle is actuated in use to vary the flow of gas between a well and a gas collection system, in accordance with a control algorithm that adjusts flow as a parameter in controlling gas extraction. The throttle is configured to ensure that there is at least some flow of landfill gas from the landfill to a gas output throughout operation. The extraction system provides an efficient system for landfill gas extraction, while mitigating a risk of creating undesired or unpleasant conditions and/or of violating regulations during operation.

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 method for evaluating, selecting, and implementing at existing nuclear surface (or near surface) sites a deeply located high-level nuclear waste (HLW) disposal repository that is located directly vertically below the areal confines of that existing site, within a particular deeply located geologic rock formation. Many of these existing sites are ideal because: they are already legally permitted and/or licensed for using nuclear/radioactive materials, they already have nuclear/radioactive materials onsite that need a long-term safe disposal solution, and many of these existing sites already have onsite useful infrastructure (e.g., roads, buildings, cooling pools, equipment, machinery, personnel, and/or the like). Such existing sites include nuclear power plants (operating or decommissioned), interim spent nuclear fuel rod assemblies (SNF) surface storage sites, and/or near surface SNF storage sites. The deep HLW disposal repository includes a vertical wellbore and may include a lateral wellbore and/or a human-made cavern.

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.

A control system for controlling extraction of landfill gas from a landfill via a gas extraction system, the gas extraction system comprising well piping for coupling a plurality of wells to a gas output. The control system comprises a controller configured to: obtain a value indicating measured energy content of landfill gas collected at the gas output from the plurality of wells; determine whether the measured energy content is different from a target energy content; and in response to determining that the measured energy content is different from the target energy content: control a plurality of valves disposed in the well piping to change flow rates of landfill gas being extracted from at least some of the plurality of wells at least in part by changing degrees to which the plurality of valves are open.

Techniques for storing hazardous material include moving a storage canister sized to enclose radioactive hazardous material through an entry of a drillhole that extends into a terranean surface and is at least proximate the terranean surface; moving the storage canister from the entry through an angled drillhole portion that is coupled to the entry and deviates from true vertical at an angle; moving the storage canister from the angled drillhole portion to a hazardous material storage drillhole portion coupled to the angled drillhole portion; moving the storage canister into the hazardous material storage drillhole portion; and forming a seal in the drillhole that isolates the hazardous material storage portion of the drillhole from the entry of the drillhole.

A control system for controlling extraction of landfill gas from a landfill via a gas extraction system, the gas extraction system comprising well piping for coupling a plurality of wells to a gas output. The control system comprises a controller configured to: obtain a value indicating measured energy content of landfill gas collected at the gas output from the plurality of wells; determine whether the measured energy content is different from a target energy content; and in response to determining that the measured energy content is different from the target energy content: control a plurality of valves disposed in the well piping to change flow rates of landfill gas being extracted from at least some of the plurality of wells at least in part by changing degrees to which the plurality of valves are open.