ISO 18229:2018定义了第四代（GEN IV）核反应堆设计和建造过程中的基本技术要求。它不涉及反应堆的运行、维护和在役检查。 第四代反应堆考虑了六种反应堆概念:钠快堆、铅快堆、气体快堆、超高温反应堆、超临界水反应堆和熔盐反应堆。 附录A详细说明了不同概念的主要特征。 本文件的适用范围仅限于与核安全和防止放射性物质释放有关的机械部件 ? 在核安全和可操作性方面被认为是重要的， ? 在确保密封性、分区、引导、保护和支持以及 ? 包含和/或与流体接触（如容器、泵、阀门、管道、波纹管、箱体结构、热交换器、搬运和驱动机构）。

ISO 18229:2018 defines the essential technical requirements that are addressed in the process of design and construction of Generation IV (GEN IV) nuclear reactors. It does not address operation, maintenance and in-service inspection of reactors. Six reactor concepts are considered for GEN IV: the sodium fast reactor, the lead fast reactor, the gas fast reactor, the very high temperature reactor, the supercritical water reactor and the molten salt reactor. Annex A details the main characteristics for the different concepts. The scope of application of this document is limited to mechanical components related to nuclear safety and to the prevention of the release of radioactive materials ? that are considered to be important in terms of nuclear safety and operability, ? that play a role in ensuring leaktightness, partitioning, guiding, securing and supporting, and ? that contain and/or are in contact with fluids (such as vessels, pumps, valves, pipes, bellows, box structures, heat exchangers, handling and driving mechanisms).