Development of Erbia-Credit Super-High-Burnup Fuel: Assessment of Fuel Cycle Economics

The use of high-enrichment fuels, e.g., fuels with >5 wt% ²³⁵U, is an effective method of reducing the number of spent-fuel assemblies and improving fuel cycle economics. However, from a criticality safety point of view, such high enrichment levels would entail considerable modification of most facilities and equipment, which would require a significant investment. Erbia-credit super-high-burnup fuel offers the potential for an effective solution to this problem. The fuel is based on the concept that small amounts of erbia added to the entire amount of UO₂ powder can reduce the reactivity level to less than that observed at a 5 wt% enrichment level, thus eliminating the majority of the modifications mentioned above. In this paper, a feasibility assessment from the viewpoint of fuel cycle economics is performed to confirm the benefits of erbia-credit-fuel implementation. A simple model to consider the erbia penalty is also proposed. The results show that the generation cost can be significantly reduced by using erbia credit, although the fuel cycle cost would not necessarily decrease in any of the cases when the enrichment level is increased. In addition, implementation scenarios of erbia credit are discussed considering the current industrial situation and the reactivity penalty incurred by the usage of erbia fuel. These implementation scenarios are also considered from the viewpoint of energy security.