LONDON – A preliminary study the ARAO commissioned in partnership with Deep Isolation finds that deep borehole disposal offers a safe, cost-effective solution for disposing of spent fuel from the Slovenia TRIGA II research reactor, set for decommissioning in 2043.

Of the options studied, the most cost-effective approach would be to build one deep borehole repository for fuel from both the TRIGA II reactor and Slovenia’s Krško nuclear power plant.

The TRIGA II study follows a Dec. 14 Deep Isolation study, published by Norwegian Nuclear Decommissioning, of Krško fuel disposal options and fuel inventories from four other European countries. It concluded that deep borehole disposal is a viable, cost-effective solution for all of the five participating countries’ high-level and intermediate-level long-lived nuclear waste.   

If Slovenia decided to implement a deep borehole disposal repository for Krško fuel, then the simplest and most inexpensive way to dispose of the TRIGA II waste would be within that same repository, with the TRIGA II waste requiring just one additional disposal canister. 

Another option for TRIGA II would be to find a location where a community would be willing to host a micro-repository to dispose of all the research waste in a single borehole with a small footprint, avoiding temporary storage costs. This pathfinder project could represent an invaluable contribution to research, demonstration and site characterization for a broader national repository — regardless of whether the Slovenian government decides to build a deep borehole or a traditional mined repository for Krško fuel.

Deep borehole disposal is becoming increasingly attractive to many countries, including NND study participants — Slovenia, the Netherlands, Denmark, Norway and Croatia — because they have small waste inventories, making a mined repository a more cumbersome, less affordable option. Deep borehole disposal benefits include: safety-at-depth (shown in evidence-based modeling that exceeds expected regulatory requirements when modeled for 1 million years at peak dose); greater flexibility in repository locations; implementation in shorter timeframes; and reduced financial risk due to the maturity of drilling industry costs.

“Deep borehole disposal is an important alternative option for us to consider in Slovenia,” said Leon Kegel, Head of Planning and Development at the Slovenian Radioactive Waste Management Organisation (ARAO).  “Deep Isolation’s recent work — for Slovenia on the TRIGA II fuel and for Slovenia, Croatia, Denmark, the Netherlands and Norway on disposal of commercial spent fuel and other high-level wastes — has been very helpful in highlighting the potential benefits, the increasing maturity of, and required next steps for deep borehole disposal as an alternative or addition to engineered mined geological repositories.”

The Slovenia and NND studies make a strong case for further international collaboration on a research demonstration project to gain technical and scientific knowledge about deep borehole disposal of nuclear waste, said Chris Parker, Managing Director of Deep Isolation EMEA Ltd. 

“This is more pressing as Europe looks to invest in new nuclear power as part of its low-carbon future,” Parker said. “Deep Isolation looks forward to partnering with Slovenia and other governments on a sustainable plan for the spent fuel.” 

About Deep Isolation
Deep Isolation is a leading global innovator in nuclear waste storage and disposal. Founded through a passion for environmental stewardship, scientific ingenuity, and entrepreneurship, Deep Isolation has developed a patented solution using directional drilling and inclusive community engagement to safely isolate nuclear waste deep underground.