Integrating a deep geologic repository for spent nuclear fuel from Slovenia’s Triga II research reactor into a site at the country’s Krško nuclear power plant would be cheaper than creating a standalone site, a study has shown.
The study was carried out by Slovenia’s Agency for Radioactive Waste Management (Arao) and US-based Deep Isolation, which is developing nuclear waste disposal technologies in deep boreholes.
The results showed that co-locating spent fuel from the Triga II reactor, which is at the Jožef Stefan Institute near the Slovenian capital of Ljubljana, would avoid duplicating costs over a standalone repository, which would require independent siting and licensing.
Arao is constructing a low- and intermediate-level radioactive waste site at Vrbina near Krško, which would store waste from Krško.
The study said that a standalone repository would have an estimated lifecycle cost of €98m ($110m), whereas adding Triga II spent fuel to a Krško repository would increase lifecycle costs by 0.5%.
“The study gave us a clear comparison of disposal pathways for Triga II spent nuclear fuel,” said Sandi Viršek, chief executive of Arao.
“It showed that integrating a small inventory into a repository for the Krško spent nuclear fuel can be done with minimal additional cost, without introducing significant safety or scheduling impacts.”
The Triga II reactor recently reached a 60-year operational milestone. Triga was designed as a facility for research, education and practical applications. The reactor is owned by Slovenia’s Ministry of Higher Education, Science and Innovation, and operated by the Jožef Stefan Institute, Slovenia’s leading scientific research institute.
Government Planning New Unit At Krško
The single unit Krško plant, which has a 696-MW reactor that started commercial operation in 1983, is owned equally by Croatian utility Hrvatska Elektroprivreda and Slovenia’s state-owned power generator GEN Group, the parent company of power company Gen Energija.
A new reactor at the Krško site is being planned by the Slovenian government, without the collaboration of the Croatian side.
The Krško supplies around 20% of Slovenia’s electricity needs and 16% of Croatia’s.
Disposal in deep boreholes has been considered as an option for the permanent geological isolation of radioactive wastes since the 1950s. Deep borehole concepts have been developed in countries including Denmark, Sweden, Switzerland and the US but have not yet been implemented.
Deep Isolation’s borehole technology uses directional drilling to securely isolate waste deep underground, offering countries an alternative to conventional mined repositories. The technology features horizontal, vertical, or slanted boreholes deep underground.
