Overview
IEC 61500:2018 defines requirements for data communication in instrumentation and control (I&C) systems important to safety for nuclear power plants, specifically for equipment performing category A functions. The third edition (2018) addresses on-line plant data communication, interface requirements between category A systems and lower‑importance systems (category B, C and non‑safety), and requires categorization of communication functions per IEC 61226. This standard is intended for operators, manufacturers, system evaluators and licensors involved in nuclear I&C.
Key technical topics and requirements
- Scope and intent
- Requirements for data communication within systems performing category A functions and between divisions of such systems.
- Interface requirements for connections to systems of lower safety importance.
- Reference architecture
- Functional/properties requirements for on‑line plant data communication are given by reference to IEC 60880 and IEC 60987 (within the IEC 61513 framework).
- Categorization
- Communication functions must be categorized in accordance with IEC 61226 to determine safety class and applicable rigour.
- Safety and dependability
- Requirements for functional independence, reliability, self‑supervision, failure detection and failure mitigation.
- Emphasis on prevention of failures including consideration of common‑cause failures (CCF).
- Separation and isolation
- Electrical isolation and physical separation requirements for communication equipment and links.
- Testing, qualification and maintenance
- Guidance on qualification, testing, maintenance and modification of data communication equipment and links.
- Cybersecurity
- Inclusion of cybersecurity considerations for communications used by safety‑important systems.
- Principles over specific technologies
- The standard focuses on principles rather than prescribing specific technologies, to remain applicable as industry practices evolve.
Practical applications and users
Who uses IEC 61500:
- Nuclear plant operators and utilities specifying I&C requirements for safety systems.
- Manufacturers and suppliers of data communication equipment for nuclear I&C.
- Systems integrators, safety assessors and licensing bodies evaluating compliance.
- Maintenance and QA teams implementing testing, modification and qualification programs.
Practical uses:
- Defining communication architecture for distributed safety systems.
- Specifying interface and separation requirements between safety and non‑safety networks.
- Establishing testing, qualification and cybersecurity measures for on‑line plant data links.
- Supporting procurement, licensing documentation and safety case development.
Related standards
- IEC 61513 (general I&C requirements for nuclear safety)
- IEC 60880 (software aspects for category A computer‑based systems)
- IEC 60987 (hardware aspects for category A computer‑based systems)
- IEC 61226 (categorization of functions)
- Links to IAEA safety and security guidance where referenced by IEC SC 45A
Keywords: IEC 61500, data communication, nuclear power plants, I&C systems, category A functions, IEC 61513, IEC 60880, IEC 60987, IEC 61226, cybersecurity, reliability, qualification.