Press Release, February 1, 2021

Study: Estonia’s Geology Holds Promise for Nuclear Waste Disposal

LONDON, UK — A new Deep Isolation study commissioned by advanced reactor deployment company Fermi Energia discusses the potential suitability of areas in Estonia considered for siting a deep horizontal borehole repository for nuclear waste. This preliminary study found no fundamental geologic limitations to disposing of nuclear waste in deep horizontal boreholes and that a wide range of locations could be demonstrated to comply with IAEA Safety Regulations for geologic disposal.

The study is a qualitative geological assessment of Estonia’s crystalline basement rock that evaluates geological conditions and potential risk factors for Estonia’s 15 counties, screening their potential for hosting a deep borehole repository. Such a repository would isolate radioactive elements from the Earth’s surface for 1.3 million years. At that point, any elements that might reach the surface would be three orders of magnitude below levels deemed safe and allowable by international safety standards.

With Estonia aiming to reduce carbon emissions by 70 percent by 2030, advanced nuclear power generation from small modular reactors (SMRs) could contribute to Estonia’s carbon-neutral future. Yet the unresolved issue of how to permanently dispose of spent nuclear fuel is a major obstacle to deploying nuclear energy worldwide.

“If we are to be successful in our efforts to see Estonia become the first European Union country to deploy an SMR in the 2030s, it is important that we take responsibility now in planning for spent fuel disposal,” said Kalev Kallemets, CEO of Fermi Energia, an emerging company of nuclear and energy professionals founded to deploy SMRs in Estonia. “This Deep Isolation study indicates that a deep borehole disposal repository could meet all prerequisites and be safe and cost-effective as well as easily deployed and scalable.”

There are about 50 small modular reactor designs and concepts being developed globally, according to the International Atomic Energy Agency. Deep Isolation is partnering with the advanced nuclear sector to explore the important role that borehole disposal can play. For example, a recent study published by the Electric Power Research Institute (EPRI) indicates that locating a deep borehole repository at the site of a hypothetical advanced reactor in the southeastern United States could be both safe and cost-effective. Fermi Energia is the first European company to contract with Deep Isolation on a preliminary geologic study to manage advanced reactor waste.

“As Estonia considers the role that advanced nuclear power generation can play in delivering a low-carbon future for the country, citizens and policymakers can feel confident there is a safe and affordable way to dispose of the resulting spent nuclear fuel,” says Chris Parker, Managing Director, Deep Isolation EMEA Limited. “We applaud Fermi Energia for doing the right thing by planning for disposal of the nuclear waste up front. This is a significant step forward in confirming that regions across Estonia, in particular along the northern coast near a potential SMR site, could potentially safely host a borehole repository.”

While countries such as Finland, Sweden and France are building mined repositories for nuclear waste, a deep horizontal borehole solution in Estonia would isolate the waste much deeper — at 1,500 meters vs. about 500 meters — for potentially lower costs, as highlighted in a recent EPRI feasibility study.  Deep boreholes are more quickly deployed, given that drilling can be done in weeks, while mining can take years and even decades.  As the geology near the potential Estonian SMR site appears suitable for disposal, the costs and risks of transporting waste long distances can be avoided. And they’re likely safer because there are no workers underground.

Deep Isolation’s solution would place the waste in corrosion-resistant canisters within deep boreholes drilled into rock formations that have been isolated from the biosphere for a million years or more.  The waste can be retrieved during a determined timeframe or permanently secured.

The study was conducted in collaboration with Engineering Bureau STEIGER LLC, Estonia’s foremost geologic and drilling company.

Deep Isolation will present the results of this study as part of Fermi Energia’s one-day SMR conference, New Generation Nuclear Energy in Estonia, on Feb. 9. Please register here.


Deep Isolation is a leading innovator in nuclear waste storage and disposal. Founded upon values of environmental stewardship, scientific ingenuity, and social responsibility, Deep Isolation offers a solution that leverages directional drilling technology to safely isolate nuclear waste deep underground.


Fermi Energia’s mission is to bring Estonian energy production into the 21st century by developing a modern small nuclear power plant that will ensure Estonia’s security of electricity supply in all weather, at a favorable price for electricity consumers, to meet the country’s climate goals.

Press Contacts:

Kari Hulac – Deep Isolation 

Mihkel Loide – Fermi Energia
+372 53 001 777