Carbon neutrality has been committed by over 100 countries to avoid the severe consequences of climate change caused by carbon emissions. As one of the key contributors to the low-carbon-emission energy system, nuclear energy has drawn much attention in both academia and industry. This paper discusses the role of nuclear energy in carbon neutrality and the development of the associated technologies. The contribution of nuclear energy to electricity generation is summarized and its non-electric applications are thoroughly reviewed, particularly in heat generation, hydrogen production, and desalination. It also presents the development of advanced nuclear reactors, including the 4th generation nuclear reactors and the small modular reactors (SMRs), which have significant advantages in safety, economics, sustainability, and non-electricity service. Challenges of nuclear energy utilization are discussed at the end, including power plant aging, safety concerns, unfavorable government policies, and public attitudes.