BS EN IEC 61226:2021

What is BS EN IEC 61226 about?  

BS EN IEC 61226 establishes, for nuclear power plant, 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. 

In BS EN IEC 61226 the functions are defined and categorized of the physical means that are implemented to fulfil them. In the framework of BS EN IEC 61226, the functions to be categorized are performed by I&C systems. Accordingly, they are called I&C functions. 

Note 1: BS EN IEC 61226 applies to: 

• The functions important to safety that are performed by I&C systems and supported by electrical power systems (categorization of I&C functions) 
• The I&C systems that enable those functions to be implemented (classification of I&C systems) 

• The electrical power systems that support those functions (classification of electrical power systems) 

Note 2: BS EN IEC 61226 applies to I&C and electrical power systems for new nuclear power plants as well as for modification and modernization of existing plants. 

Who is BS EN IEC 61226 for? 

BS EN IEC 61226 on nuclear power plant is useful for: 

• Electricity generation company 
• Companies dealing with nuclear decommissioning 
• Authorities dealing with Nuclear Power plant 

Why should you use BS EN IEC 61226? 

A nuclear power plant (NPP) is a thermal power plant station in which the heat source is a nuclear reactor. That heat is used to generate steam that drives a steam turbine connected to a generator which helps in producing electricity. 

This International Standard BS EN IEC 61226 responds to an International Atomic Energy Agency (IAEA) requirement1 to identify and classify nuclear power plants important to safety items on the basis of their functions and safety significance. 

The intent of BS EN IEC 61226 to establish the criteria and methods to be used to: 

• Identify and assign the functions important to safety into categories, depending on their contribution to the prevention and mitigation of postulated initiating events (PIE) 
• Classify accordingly the I&C and electrical power systems which are necessary to perform these functions. 

Correct categorization of functions is essential to ensure the appropriate degree of attention by the plant's designers, operators and regulatory authorities to the specification, design, qualification, quality assurance (QA), manufacturing, installation, maintenance, and testing of the systems that ensure the safety functions. 

BS EN IEC 61226 establishes the criteria and methods to be used to assign the functions of a NPP accomplished by I&C and electrical power systems to three categories A, B and C, which depend on the importance of the function for safety. Functions with no direct safety roles are non-categorized (NC). 

What’s changed since the last update? 

BS EN IEC 61226:2021 supersedes BS EN 61226:2010, which is withdrawn. 

BS EN IEC 61226:2021 includes: 

• 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. 
• 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