Spent fuel management is the academic and practical field concerned with the safe, secure, and environmentally responsible handling of nuclear fuel that has been irradiated in a nuclear reactor. This interdisciplinary concept investigates the technical, regulatory, economic, and societal aspects of the entire post-irradiation lifecycle, encompassing interim storage, transportation, potential reprocessing, and final disposal of spent nuclear material. Key characteristics include addressing the long-term radiological hazard, ensuring physical security, mitigating proliferation risks, and navigating complex international and national regulatory landscapes. Its significance is paramount for the sustainable and publicly acceptable deployment of nuclear energy, focusing on minimizing environmental impact and ensuring long-term safety for future generations.