Firms will explore borehole technology for waste generated by underground nuclear reactors
US small modular nuclear reactor (SMR) startup Deep Fission and Deep Isolation, a nuclear waste disposal technology firm, have signed a memorandum of understanding to collaborate on managing spent fuel from Deep Fission’s proposed plants.
According to a statement, the partnership will see the two firms explore the potential licensing and use of Deep Isolation’s deep borehole disposal technology for radioactive waste generated by Deep Fission's underground nuclear reactor fleet.
Deep Fission has plans to deploy SMRs approximately one mile (1.6 km) underground.
Earlier reports have said that the Deep Fission Borehole Reactor 1 (DFBR-1) is a pressurised water reactor (PWR) that produces 15 MWt (thermal) and 5 MWe (electric) and has an estimated fuel cycle of between 10 to 20 years.
The reactor is designed to fit in a borehole under one metre wide, using deep geological layers for natural pressurisation and containment – an approach the company says enhances security and reduces costs.
Deep Isolation’s borehole technology uses directional drilling to securely isolate waste deep underground, offering countries an alternative to conventional mined repositories.
The company’s technology has not been deployed, but Deep Isolation has said that given regulatory approval in the US, and “the right customer and government support”, it can be ready to deploy within two to three years.
In January 2025, Deep Fission and Endeavour Energy announced a partnership to co-develop 2 GW of nuclear energy, using Deep Fission's underground SMRs to power Endeavour's data centres, with the first reactors expected to be operational by 2029.
