IEC 61226:2020为核电厂建立了一种根据其对安全的重要性将工厂指定的功能分配到类别的方法。基于指定的类别，对执行或支持这些功能的I&C和电力系统进行后续分类，然后确定相关的设计标准。 当应用设计标准时，根据其对安全的重要性确保每个功能的实现。在本文件中，标准是功能性、可靠性、性能、环境鉴定（如抗震）和质量保证（QA）。 与上一版相比，此版本包括以下重大技术变更: -与原子能机构的要求、建议和术语保持一致，特别是考虑到NS的更换-R-1通过SSR 2/1和SSG 30的发表； -将范围扩展到电力系统； -将适用于功能和I&C系统的详细要求移至规范性附件，该附件将在更新IEC 61513后删除。

IEC 61226:2020 establishes, for nuclear power plants, a method of assignment of the functions specified for the plant into categories according to their importance to safety. Subsequent classification of the I&C and electrical power systems performing or supporting these functions, based on the assigned category, then determines relevant design criteria.
The design criteria, when applied, ensure the achievement of each function in accordance to its importance to safety. In this document, the criteria are those of functionality, reliability, performance, environmental qualification (e.g. seismic) and quality assurance (QA).
This edition includes the following significant technical changes with respect to the previous edition:
- to align on IAEA requirements, recommendations and terminology, particularly to take into account the replacement of NS-R-1 by SSR 2/1 and publication of SSG 30;
- to extend the scope to electrical power systems;
- to move the detailed requirements applying to functions and I&C systems to a normative annex, which will be removed after updating IEC 61513.