Amid the global energy and climate crises, phasing out fossil fuel has become an international priority. Nuclear energy is re-emerging as a fundamental constituent of several countries’ energy mixes. Sweden has updated its policy towards expanding its nuclear energy as a reflection of this global trend, but also due to national political shifts and technological ambitions. In this paper, we explore the current and future nuclear energy’s landscape in Sweden, by examining its historical context and projections. We achieve this by assessing the nuclear energy system through a sustainability lens, considering its four dimensions: feasibility, viability, desirability, and openness. Our analysis shows that, from a feasibility perspective, Sweden’s nuclear energy system must ensure a secure uranium supply and manage its spent fuel. Moreover, it should proactively address climate change impacts, such as sea level rise. From a viability perspective, the system is challenged by long lead times for nuclear plants, though Small Modular Reactors offer a potential solution by reducing costs and risk. Increased public support is in favor of the sector’s desirability, while its reliance on uranium imports puts its security at risk and highlights the critical need to reduce its openness. With a straightforward qualitative assessment, we show the imperative need for a multidisciplinary approach when crafting Sweden’s nuclear policy, to achieve a balance between national energy needs, environmental responsibilities, and the challenges of the global energy market.