Deep Isolation is the first company to develop technologies for the permanent disposal of spent nuclear fuel and high-level radioactive waste in deep boreholes. Its approach combines deep borehole disposal with a standardized canister system (the Universal Canister System, or UCS) to safely isolate waste deep underground.

The technology uses directional drilling to construct boreholes thousands of feet underground in stable geologic formations that have been separated from the biosphere for millions of years. A vertical section is drilled first, and can transition into a horizontal, angled, or remain vertical disposal section depending on site conditions and geology. Waste is placed in corrosion-resistant canisters within this disposal zone. The canisters act as an engineered barrier, while the surrounding rock provides a natural barrier.

This approach draws on established drilling methods from the energy industry, allowing boreholes to be constructed reliably and at lower cost. It also makes it possible to place waste precisely in deep, stable environments without requiring underground human access. Because disposal can take place at or near existing storage sites, it can reduce the need to transport waste long distances.

The disposal process follows a series of steps. A borehole is drilled and lined with steel casing. Waste is loaded into canisters and then lowered and pushed into the disposal section using standard oil and gas techniques. After emplacement, the access portion of the borehole is sealed with materials such as rock and bentonite clay.

The UCS supports the full lifecycle of nuclear waste management, including transportation, storage, and disposal. It is designed to handle a range of waste types and allows waste to be packaged once and kept in the same canister through each stage. The system was developed through the U.S. Department of Energy ARPA-E Project UPWARDS and further advanced under Project SAVANT, using corrosion-resistant materials suited for deep geologic conditions.

As part of Deep Isolation’s 2026 full-scale demonstration program, the UCS is being used to validate handling, emplacement, and retrieval under real-world conditions and to support future deployment at scale.

Mined repository concepts rely on large underground facilities made up of tunnels and rooms excavated in rock formations. These repositories are typically a few hundred to about a thousand meters deep and require the removal of significant volumes of rock, along with extensive surface and underground infrastructure for construction, operation, and closure.

Deep Isolation’s approach instead uses small-diameter boreholes constructed with directional drilling technology. These boreholes can extend from a few hundred meters to several kilometers in depth and can be vertical, angled, or horizontal depending on the geology and site design.

Because deep boreholes are much narrower than mined tunnels, they disturb far less of the surrounding rock. The system also avoids the need for people to work underground, since waste can be emplaced and, if needed, retrieved using standard drilling equipment from the surface.

The Nuclear Regulatory Commission (NRC) requires waste to be retrievable for a period of time. The drilling industry regularly retrieves objects and monitoring instruments from drillholes, and the process is standard. Before a Deep Isolation drillhole is sealed, an expert crew could still retrieve the waste, but it would take a week or possibly longer. Doing so is sufficiently complex to offer substantial security from a terrorist attempt to retrieve the waste. We have already demonstrated the canisters can be retrieved.

Deep Isolation systems are designed to support monitoring and operational control throughout the disposal process. During emplacement, downhole instrumentation measures temperature and radiation conditions, while post-closure monitoring is conducted through surface and near-surface systems.

Waste remains retrievable for a defined regulatory period using established drilling industry techniques. Retrieval operations involve re-entering the borehole and removing canisters using specialized tools. 

Both emplacement and retrieval have been demonstrated in field testing, including a 2019 directional drilling demonstration, and are being further validated through the 2026 ongoing full-scale demonstration program using the Universal Canister System.

Nuclear waste disposal is a global challenge and we are developing a solution that can be adapted to work in a number of different geologic settings. 

One mile is typical; in some locations, the best depth might be a few thousand feet; at others, it might be two miles or more. The waste is placed far below aquifers, in regions in which water has had no contact with the surface for thousands to millions of years or more. What we are seeking are the geologic environments best suited to dispose of the waste for the years to come.

Depth is closely tied to geology. Rather than relying on a single type of rock, the approach is designed to work in a range of geologic settings, as long as they show evidence of long-term isolation. This includes formations where groundwater has had no contact with the surface for millions of years, which can be confirmed through isotopic dating methods.

In addition to past isolation, site selection considers rock properties and the surrounding seismic and hydrologic conditions. Suitable formations typically have low permeability, limit fluid movement, and can slow or restrict the transport of radionuclides. These characteristics are often found in deep sedimentary rocks such as clays, shales, and mudstones, as well as in salt formations. In some regions, crystalline rocks like granite may also be suitable if they demonstrate long-term stability and isolation. In these environments, groundwater at depth can remain separated from the surface for tens to hundreds of millions of years.

At these depths, groundwater is often highly saline and chemically reducing, conditions that can further limit corrosion and reduce the mobility of contaminants. Together, these natural conditions add to the effectiveness of the engineered barriers used in the disposal system.

Directional drilling makes it possible to place waste precisely within these carefully selected formations. Because suitable geologic environments exist in many parts of the world, this approach can be adapted to different regions following detailed geologic, hydrologic, and seismic studies.

Deep Isolation’s approach is designed to protect workers, the public, and the environment at every stage, from handling and emplacement to long-term storage underground.

During handling and emplacement, the process uses well-established methods already proven in the nuclear industry. Spent fuel is moved using shielded systems, remote operations, and trained personnel, with strict procedures in place to minimize exposure and establish safe operations.

Once underground, protection comes from multiple layers, including the corrosion-resistant canisters, lined and sealed boreholes, and surrounding stable rock formations deep below the surface. These formations are specifically selected because groundwater moves extremely slowly and has often been isolated for millions of years, helping to limit any potential movement of radioactive material.

Deep Isolation also evaluates long-term performance through detailed safety analyses, including how radionuclides might move through groundwater over very long timescales. These studies are used to design systems that meet strict regulatory standards for radiation exposure, with targets well below established limits.

In addition to environmental protection, the depth and geologic setting provide a strong physical barrier that enhances security. Although the spent fuel is retrievable, doing so requires setting up a rig, removing thousands of feet of rock and bentonite sealant, and operating a fishing system to pull up canisters one at a time, making unauthorized access highly unlikely.

Deep Isolation’s system is designed to be flexible, allowing deployment in a range of configurations depending on geology, regulatory requirements, and stakeholder preferences. Disposal boreholes may be located at or near existing reactor sites or at regional or centralized facilities.

This flexibility makes it easier to work with local communities while reducing the need to transport waste long distances. Facilities are developed in partnership with communities and states that provide informed consent and determine that deep geologic disposal is the preferred option. Many communities are already managing nuclear waste stored above ground and placing that waste deep underground can offer a more permanent solution while avoiding the need to move it elsewhere. Public engagement has shown that people often prefer options that limit transportation and focus on improving safety.

Deep Isolation has talked with people in many affected communities and in 2018 engaged the highly respected firm GfK Global to survey the opinions of people living in over 20 states. On average 82% of those surveyed prefer deep burial on-site rather than transportation over local roads to distant storage facilities. They do not want waste brought in to their communities from outside, nor do they want waste transported across their state. Read the results.

Deep Isolation will only work with communities and states that give their support for the permanent isolation of nuclear waste in their community and state. If a community and state are not interested in our permanent disposal method, they can still advocate for the waste to be shipped to an interim site, or a different disposal facility when one becomes available.

The decision process as to whether a community and state would prefer to transport waste to another location or dispose of it nearby is a complex one. Potential benefits of permanent isolation in their community and state include a timely solution that improves safety, minimizes transportation, adds jobs, and provides new fees for the use of land. Only if the community and state decide the benefits make it worthwhile would a site be selected there.

Deep Isolation will work with communities and states to help them make an informed decision about which option is the best fit for them. With over 60 locations in the United States that are currently storing nuclear waste in pools or dry casks, we have indications that at least a few of them are interested in exploring the option of a Deep Isolation facility.