Highly radioactive residues from nuclear reactors do not have a definitive disposal solution. Not in France, not in the United States, not anywhere else. Most countries temporarily store these residues. No one knows yet what to do with them. An American company proposes a solution: burying highly radioactive materials several kilometers underground.
A deep drilling into the rock can isolate nuclear waste for millennia
The cavities used will resemble those of the oil industry. The drillings can be horizontal, vertical, or inclined depending on the site’s geology. The project was carried out through the ARPA-E’s ONWARDS program. Oklo and the Argonne and Idaho laboratories participated. In March 2026, Deep Isolation reached a new milestone by validating this approach for residues from advanced nuclear fuel recycling.
Physical modeling shows that residues buried in shale or granite rocks remain well below the current radiological standards. According to Interesting Engineering, simulated exposure levels are several orders of magnitude below the regulatory threshold selected for the model. The World Nuclear Association also points out that 800 wells would be enough to store the entire American stock.
Deep Isolation, Oklo, and two national laboratories validated this approach together
The goal was to verify the compatibility between the residues from Argonne’s electrorefining process and Deep Isolation’s deep drillings. The results confirm this compatibility and pave a concrete path towards closing the metallic fuel cycle. This process separates recoverable materials from ultimate residues, reducing their volume and radioactive lifespan. Oklo also announced in August 2025 the design of a recycling plant in Oak Ridge, Tennessee, strengthening the need for a suitable storage solution for these specific waste.
The company developed its Universal Canister System over three years. The US Department of Energy funded this project. With 99 patents filed to date, the company positions itself as the first to commercially develop this technology. In January 2019, it conducted the world’s first demonstration in front of forty observers from several countries, placing and retrieving a prototype container in a horizontal borehole. Since 2023, a large-scale demonstration center has been operating in Texas. However, a legal limit remains. Current US law still does not allow drilling deposits for highly radioactive waste.
How this technology could change the global management of nuclear waste
In the United States, the estimated debt for non-disposal of these residues reached at least $37.6 billion in 2024. The Yucca Mountain project, envisioned as a geological storage site, remains blocked by political and legal opposition. Deep drilling can be constructed in less than two years. Their modularity allows for regional or on-site implementation. Their unit cost remains significantly lower than that of a mining site.
The technology is of interest beyond American borders. Deep Isolation claims it can adapt its solution to the waste inventories of any country. For nations with low volumes of residues, a single well could be sufficient to treat their entire stock. The potential market is estimated at $600 billion globally. If the law changes, 800 wells would be enough to treat the entire national stock of highly radioactive residues.
