小型核反应堆具有良好的安全特性、模块化建造方式和广泛的应用领域，已成为国际上重要的核能研发工作。相对于百万千瓦级大型核电站而言，外部约束条件（应急计划是其中之一）对小型堆的经济性具有更大的影响，尤其是对需要靠近用户的小型核反应堆（例如供水、供热等）更是如此。作为克服这种约束条件的一个重要策略，小型核反应堆在设计上追求更高的安全特性。对于需要靠近用户的小型核反应堆（例如供热、供汽等），将应急计划区限制在厂址范围之内，对保障小型核反应堆的经济性和增强公众的接受性非常有益。事实上，许多小型核反应堆都将烟羽应急计划区限制在厂址边界作为重要的设计目标之一。从目前经验看，完全取消小型核反应堆的场外应急准备的可能性不大，但考虑其安全特性、简化小型核反应堆的应急准备是国际上的共识。介绍了小型核反应堆的研发现状，讨论了大型核电机组与小型核反应堆应急计划在理念和实现方式上的差别，分析了国际上有关小型核反应堆应急准备简化的有关讨论和实践。

Small modular reactors (SMRs) have been an important international R&D activity because of their inherent safety features, modular construction approach and wide application perspectives. Compared with large scale nuclear power plants (e.g. 1000MWe light water reactor units), the economic performance of SMRs will be more sensible to outside constraints. It is especially the case for SMRs located in the very vicinity of the potential users. One of the possible constraints involves nuclear emergency preparedness and response. It would be very beneficial to the economic performance and the public acceptance towards SMRs if the plume emergency planning zones of them could be limited to their site boundaries. In fact, many concepts of SMRs have put this as one of their important design goals. Considering the factors in emergency planning, it would be currently not feasible to eliminate off-site emergency preparedness. However, it has been an international consensus that emergency planning could be simplified. For example, the emergency planning zones for SMRs may be significantly smaller than that for large scale light water nuclear power plants. This paper describes the current status of international R&D activities in the field of SMRs. The concepts and approaches governing the emergency planning in support of large light water reactors and SMRs are discussed. Relevant discussions and practice concerning simplification of emergency preparedness for SMRs are also briefly presented.