A pilot study by the Swedish company Studsvik shows that the Norway’s used fuel can be treated in less than two years, Norwegian Nuclear Decommissioning (NND) said.
Parts of the Norwegian nuclear fuel are unstable metallic uranium which is extra challenging to handle. Several studies have recommended chemical treatment of this fuel before it goes to an underground landfill for permanent storage. “The work to achieve the necessary final storage for the Norwegian nuclear fuel is of national importance and has a high priority. This study therefore comes with very interesting information, says NND technical director Nils Bøhmer.
The method, called the Studsvik Small Scale Conversion process, has previously only been performed on a small sample of used nuclear fuel. In this project, Studsvik built up the necessary equipment and performed a successful test of the method on a larger scale of more than 30 kilos of fuel that corresponds to the Norwegian metallic fuel.
“The collaboration with NND to develop the method Studsvik Small Scale Conversion process has been good and efficient. Together, we have quite quickly managed to go from the drawing board to try out and document that the method is feasible, and we are convinced that this is a safe and effective long-term solution for handling spent metallic uranium fuel,” said Joakim Lundström, Business Area President Fuel and Materials Technology at Studsvik.
The treatment method, oxidation, involves heating the metallic uranium fuel with hot air in a furnace, and converting it to stable uranium dioxide. “This study shows more technological maturity than previously thought and reduces the uncertainties surrounding the implementation of the treatment. Thus, we have received confirmation that this treatment can be a good solution to stabilise the Norwegian fuel so that it becomes more suitable for final storage, noted Bøhmer. “I am not surprised that it is feasible to treat larger amounts of fuel, but it is a positive surprise that the method proves to be so effective that all the Norwegian metallic fuel, about 10 tons, can be treated in two years. Since it goes faster than expected, we have also asked for an updated cost picture to see if it will be cheaper to implement.”
The final decision on treatment of the fuel, before it goes to final storage, will be made by the Storting (Norwegian parliament). Before that, a separate study run will be carried out according to the state's project model for large investments. In June 2020, NND completed a limited concept selection study (KVU) for handling the used fuel, where various methods for chemical treatment to stabilise the fuel were considered; reprocessing by France’s Orano and oxidation by Studsvik. In the report, NND's professionals make clear recommendations that the fuel should be treated chemically before disposal.
The report has undergone external quality assurance (KS1) and the KS1 report is now ready and for processing at the Ministry of Trade and Industry. The results from the pilot study will be included in a further study on the treatment of used Norwegian nuclear fuel.
Norway has about 17 tonnes of nuclear fuel used according to the Department of Energy Technology (IFE)'s research activity at Kjeller and in Halden. About 10 tonnes of the nuclear fuel is metallic uranium. Used nuclear fuel is classified as high-level radioactive waste, which means that it can be harmful to humans and the environment for hundreds of thousands of years. The warehouses where the used fuel is located today do not satisfy current requirements, therefore one of the Norwegian nuclear decommissioning (NND) and IFE's most important tasks is to find safe solutions for storage and disposal.
NND is a government agency established in 2018 under the Ministry of Trade and Industry. NND has two main tasks: Decommissioning the Norwegian nuclear facilities and handling all man-made radioactive waste for the benefit of current and future generations.
In time, NND will take over IFE's licence and ownership of the nuclear facilities. This means that both facilities and personnel will be transferred to NND's organisation, the target being the start of 2024.
Although IFE is currently responsible as the licensee and owner of the facilities, IFE and NND work closely together to handle the clean-up after the nuclear activities.