Nuclear energy is being reconsidered worldwide as a low-carbon and dispatchable energy source. Following the development of Small Modular Reactors (SMR) to reduce the capital costs and increase the safety of new nuclear power plants, microreactors are being designed by several companies. Microreactors are usually defined as SMR with a power output in the range 1–20 MW_e. They can operate as part of the electric grid, independently from the electric grid or as part of a microgrid to produce electricity and process heat. In the present paper, some microreactors at an advanced design stage are presented: eVinci™, Aurora, Holos Generators, Xe-Mobile, NuScale, Sealer, U-Battery and Micro Modular Reactor. The main applications of microreactors and the technology features are then discussed to present the main potentialities and challenges. The main advantages are the small size, the simple plant layout and the fast on-site installation. The main challenges are the limited fuel availability, the security and proliferation risk and the licensing process. Finally, an economic analysis shows that, due to an economy of scale, despite the capital cost reduction, microreactors are not cost competitive with large nuclear plants, but they are competitive with technologies with similar scale and application, such as diesel generators and renewable sources in microgrids.

核能正在世界范围内重新考虑作为一种低碳和可调度的能源。在开发小型模块化反应堆 (SMR) 以降低新核电站的资本成本和提高安全性之后，几家公司正在设计微型反应堆。微反应器通常定义为功率输出范围为 1-20 MW _{e 的}SMR. 它们可以作为电网的一部分运行，独立于电网或作为微电网的一部分来发电和处理热量。在本文中，介绍了一些处于高级设计阶段的微反应器：eVinci™、Aurora、Holos Generators、Xe-Mobile、NuScale、Sealer、U-Battery 和 Micro Modular Reactor。然后讨论微反应器的主要应用和技术特征，以展示主要的潜力和挑战。主要优点是体积小、厂房布置简单、现场安装速度快。主要挑战是有限的燃料供应、安全和扩散风险以及许可程序。最后，经济分析表明，由于规模经济，尽管资本成本降低，