US-based nuclear waste storage and disposal company Deep Isolation has completed its Project SAVANT (Sequential Advancement of Technology for Deep Borehole Disposal), a two-year research initiative funded by the US Department of Energy (DOE) Advanced Research Projects Agency–Energy (ARPA-E).
Deep Isolation is the first company to undertake development of technologies for nuclear waste disposal in deep boreholes. Deep Isolation has started a planned three-year initiative to complete a full-scale, at-depth demonstration of its Universal Canister System (UCS) and deep borehole solution.
Deep Isolation leverages standard drilling technology using off-the-shelf tools and equipment used in the oil and gas drilling industry. It envisages emplacing nuclear waste in corrosion-resistant canisters – 22-33 centimetres in diameter and 4.2 metres long – into drillholes in rock. The drillhole, lined with a steel casing, begins with a vertical access section which then gradually curves until it is nearly horizontal, with a slight upward tilt.
This horizontal ‘disposal section’ would be up to two miles (3.2 kilometres) in length and lie anything from a few thousand feet to two miles beneath the surface, depending on geology. Once the waste is in place, the vertical access section of the drillhole and the beginning of its horizontal disposal section would be sealed using rock, bentonite and other materials.
The UCS, developed in collaboration with NAC International, is designed to accommodate a range of advanced reactor waste streams, including vitrified waste from reprocessing, TRISO used fuel, and halide salts from molten salt reactors. It is compatible with modern dry storage and transport infrastructure,
Project SAVANT found that Deep Isolation’s Universal Canister System (UCS) and borehole casing materials can sufficiently resist corrosion to safely store nuclear waste material, further validating the design and advancing the Company toward a full-scale deep borehole disposal demonstration.
The project SAVANT team evaluated corrosion performance under realistic thermal, chemical, and mechanical stressors expected in a deep borehole environment. These data sets strengthen the scientific basis for Deep Isolation’s UCS and reinforce confidence in the system’s design life.
“This important study shows that Deep Isolation has achieved another critical milestone in the development of a safe method of disposing of radioactive nuclear waste – something the world critically needs,” said Rod Baltzer, Deep Isolation’s President and CEO. “Nuclear energy is facing a growing challenge. Global nuclear power capacity is forecast to increase by more than 300 GW by 2050, yet the world has not permanently disposed of any of the spent fuel it has created over the last 70 years. We believe our deep borehole technology will ultimately be the solution for safely and permanently disposal of nuclear waste deep underground, a solution the world needs.”
Jesse Sloane, Executive VP of Engineering at Deep Isolation, noted: “The project SAVANT data significantly strengthens our understanding of how UCS and borehole system materials perform under the conditions expected in a deep geologic environment. These results demonstrate wide margins of safety for the public and reinforce the robustness of our design approach. With these results in hand, we are well positioned to advance into larger scale testing.”
Stan Gingrich, Principal Engineer at Amentum and a project SAVANT collaborator, emphasised the importance of materials research in advancing disposal readiness. “The corrosion testing produced data representative of deep borehole disposal environments,” said Gingrich. “Our collaboration with Deep Isolation, including our co-authored paper on the results of materials under high temperature and pressure conditions (presented at Waste Management Symposia 2025), underscores how phased testing can bring innovative disposal solutions closer to reality.”
The project also incorporated supply chain research and cost estimation developed in partnership with the Electric Power Research Institute (EPRI). This highlighted opportunities to build domestic manufacturing pathways for canisters, casing materials, and deployment equipment that could accelerate commercial readiness and reduce lifecycle costs for future disposal facilities.
In December 2025, Deep Isolation also completed Project UPWARDS (Universal Performance Criteria & Canister for Advanced Reactor Waste Form Acceptance in Borehole & Mined Repositories Considering Design Safety) carried out in partnership with the University of California, Berkeley, Lawrence Berkeley National Laboratory, and NAC International.
Earlier, in May 2025, Deep Isolation had completed Project PUCK, a US government-funded initiative to demonstrate the potential commercial readiness of the UCS to manage TRISO used fuel. Deep Isolation worked with Kairos Power to conceptually evaluate the use of TRISO pebble fuel, verifying UCS as a safe, scalable solution. Project PUCK (Performance Validation of the Universal Canister System for Kairos Power) was launched in July 2024 under a Small Business Innovation Research (SBIR) grant from DOE.
