A preliminary study by the Slovenian Radioactive Waste Management Organisation (ARAO) commissioned in partnership with Deep Isolation has found that deep borehole disposal offers a safe, cost-effective solution for disposing of spent fuel from Slovenia’s TRIGA II research reactor.
The Triga reactor, located at the Josef Stefan Institute in Ljubljana produces radioactive isotopes for medical research and for training. It is schedule 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.” Deep Isolation said. This would require just one additional disposal canister, it added.
“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,” Deep Isolation said.
Leon Kegel, head of planning and development at the Slovenian Radioactive Waste Management Organisation (ARAO) said deep borehole disposal is “an important alternative option for us to consider in Slovenia.”
The study follows a December report published by Norwegian Nuclear Decommissioning (NND) that found boreholes to be a viable option for Slovenia's Krško power plant fuel and nuclear waste from four other European countries.
“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,” said Kegel.
Deep Isolation said borehole disposal is becoming increasingly attractive to many countries, including NND study participants because they have small waste inventories, making a mined repository a more cumbersome, less affordable option.
It said: "The benefits of borehole disposal include: safety-at-depth (shown in evidence-based modelling that exceeds expected regulatory requirements when modelled 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."
Photo: Slovenia's TRIGA II research reactor (Credit: Jožef Stefan Institute)