New Waste Management Options Created by iMAGINE through Direct Operation on Spent Nuclear Fuel Feed

The demand for improving the nuclear waste management has since long been identified as one of the major hurdles for widespread use of nuclear energy. Nuclear waste management, through partitioning and transmutation (P&T), has been researched since the 1990s with partitioning being a prerequisite for the process. Recently, an innovative approach of reactors directly operating on spent, or nowadays often called used nuclear fuel, iMAGINE has been proposed which could deliver on the aims of P&T as a side effect to more efficient and sustainable nuclear energy production in the future. A HELIOS model of the core has been used to analyze the long-term operation of a molten salt reactor including the investigation of the minor actinide accumulation over the entire burnup period. The results shown here confirm that long-term reactor operation is possible, even with higher amounts of vitrified waste loaded. Thus, it is possible to achieve the aims of P&T without prior partitioning, but it is certainly less efficient since the high concentration of minor actinides (MAs), required for efficient burning, is impossible to obtain in a short operational time. On this basis, the proposed nuclear waste management approach will be a long-term effort when it is accomplished without partitioning/separation technologies. However, none of the analyses contradicts this effort. The key points are: (a) when the technology for treating the waste is possible and reliable, the time horizon will not be a major concern; (b) the waste management is now intrinsically linked with energy production instead of requiring dedicated costly facilities, delivering a promising economic basis; (c) the waste management is now associated with long-term energy production and massively improved resource utilization. The study of feedback effects has shown that the modeled system has a strong negative feedback effect of ~−6 pcm/K, and even with spent nuclear fuel feed reduces to ~−3.8 pcm/K, ensuring the basis for a safe operation. In summary, it has been demonstrated that the objectives of P&T are achievable without prior partitioning, an approach which was never even discussed in the past. These ground-breaking results and the new insights will allow or even require rethinking the nuclear waste management of the future.