SMRSiMa: SMR Waste Management and Siting: Waste Management and Societal Engagement

Meeting European Unions ambitious carbon neutrality targets requires low carbon intensity electricicity and other energy production. Finland’s target is to reach carbon neutrality by 2035 and Small Modular Reactors (SMR) are envisioned to help reaching the target, especially in heat production. Nuclear Energy is a low carbon intensity power source and modularity and serial production is estimated to bring the price of SMRs down when compared to conventional Nuclear Power Plants (NPP)s. While need for nuclear power and SMR siting topics have been discussed by the stakeholders in media during the past years, waste management issues have not been as common topics. This report summarises work conducted in the SMRSiMa project during 2023 on both SMR waste management and societal engagement topics. The project is funded by SAFER2028 and is a continuation of KYT funded SMRWaMa and SMRSiMaprojects. The project is coordinated between VTT, GTK and LUT and divided into four work packages, out of which WP1, WP2 and WP4 results are reported here. GTK also prepared a research report on WP3 considering geological siting topics for the project.

In the first WP, preliminary studies were performed on criticality safety related to the final disposal of the spent fuel. These calculations were based on the fuel assembly models available in public NuScale and LDR-50 documentation and supposed to provide applicable results to any similar LWR concepts with UOX fuel in 17 x 17 asseblies. The results suggest that when e.g. 2.4 % U-235 enriched fuel is considered for LDR, the fresh fuel assumption may be acceptable for final disposal criticality safety studies. This would probably not be the case for the studied higher enrichment, i.e. 3.0 % or more, fuel. For these and the more than 4 % enriched NuScale assmeblies burnup credit will thus be needed. The WP1 chapter provides results based on several simplifications and are therefore to be understood as indicative only, with large uncertainties.

In the second work package the focus was on SMR waste management topics. The objective was to find out Finnish stakeholders research and development needs regarding SMR’s. It also investigated disposability of both SMR Spent Nuclear Fuel (SNF) and Accident Tolerant Fuels (STF) into a KBS-3 type repository and assessed SNF storage concerns for SMRs. Fortum and TVO, both power companies operating NPPs in Finland, have preliminary considered deployment of Light-Water Reactor (LWR), while the Technical University of Lappeenranta is considering a Hight Temperature Gas-cooled Reactor (HTGR) for research purposes. The stakeholders considered both disposability of SMR fuel in KBS-3 repositories and business and modularity related concerns as important topics to be researched. Investigating disposability of both SMR SNF and ATF, it was found out that both fuel disposability, source-term information and gas generation potential of the fuels should be further investigated. Finally, dry storage in Finland is supported by the regulation, but not carried out historically in the Nordic region. Thus, best practices from Canada should be looked into to ensure long-term durability of canisters in long-term storage.

In the fourth work package the focus was on stakeholder engagement regarding SMR siting. LUT analysed results of a 2022 resident survey to Helsinki Metropolitan area. The survey investigated how opinions of residents for and against SMRs differ on SMR-related topics. The survey showed that more than half of the residents are supportive for deployment of SMRs in their municipalities, while only a third would accept disposal of spent fuel there. Trust into key actors differed between the opponents and supporters, where opponents were more likely to trust environmental organisations, while supporters trusted the Radiation and Nuclear Safety Authority, VTT and universities. In the work package, a preliminary roadmap for stakeholder engagement during SMR deployment was developed and presented in a workshop. The roadmap is a step towards building a common understanding among stakeholders in Finland.