Overview
IEC 60671:2007 is an international standard published by the International Electrotechnical Commission (IEC) focusing on nuclear power plants' instrumentation and control (I&C) systems important to safety. This standard specifically addresses surveillance testing of I&C systems that perform safety-critical functions classified as category A, B, and C under IEC 61226. It provides principles and requirements for testing these systems during both normal power operation and shutdown, ensuring their functional availability and ability to detect faults that might hinder safety function performance.
The 2007 second edition expands the scope to cover all safety-important systems, harmonizes terminology with newer standards, and strengthens the role of computer-based self-supervision as an alternative or supplement to periodic testing. This makes IEC 60671 essential for maintaining the reliability and readiness of safety-related I&C equipment in nuclear power plants worldwide.
Key Topics
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Scope and Principles of Surveillance Testing: The standard sets out the foundational principles for executing surveillance testing on I&C equipment critical to safety. It addresses testing during plant operation and shutdown, emphasizing fault detection and system availability.
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Categorization of Safety Functions: IEC 60671 aligns with IEC 61226 by prescribing gradation of testing requirements for equipment performing category A (highest importance), B, and C safety functions. This helps prioritize testing rigor and frequency accordingly.
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Testing Methods: Surveillance testing may include:
- Functional tests at periodic intervals
- Continuous or short interval testing to detect faults promptly
- Self-supervision capabilities embedded in computer-based I&C systems to allow continuous fault diagnosis without manual testing
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Design and Application of Test Equipment: The standard details basic rules for designing test equipment and its interfaces with safety systems to ensure testing does not impair safety functions.
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Testing Specific Components: Detailed requirements cover sensors and signal processing devices, electromechanical equipment (such as relays and valves), and logic assemblies, including digital and computer-based systems.
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Data Recording and Fault Management: Guidelines emphasize accurate recording of test data, fault detection outcomes, and response metrics like set-point verification, test intervals, response times, and restoration procedures.
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Integration with Related Standards: IEC 60671 complements and references other IEC standards, notably IEC 61513 (top-level requirements for I&C systems), and aligns with International Atomic Energy Agency (IAEA) safety guides.
Applications
IEC 60671:2007 applies primarily to:
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Nuclear Power Plant Operators and Engineering Teams: To establish rigorous surveillance testing programs that ensure I&C systems reliably perform their safety functions.
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I&C System Designers and Manufacturers: To design safety-related instrumentation and control systems incorporating surveillance testing features and facilitate both manual and automated testing.
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Regulatory and Safety Assessors: For evaluating the adequacy of surveillance testing procedures and I&C system readiness in compliance with international safety requirements.
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Maintenance Personnel: To plan and perform testing at appropriate intervals and manage test data for fault diagnosis and restoration activities.
Utilizing IEC 60671 enhances plant safety, reliability, and regulatory compliance by ensuring I&C systems critical to nuclear plant safety are continuously monitored, tested, and maintained in a state of readiness.
Related Standards
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IEC 61226:2005 – Classification of I&C functions important to safety into categories A, B, and C, forming the basis for testing requirement gradation.
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IEC 61513:2001 – Establishes top-level safety requirements for I&C systems in nuclear power plants, underscoring the necessity for demonstration of readiness and fault tolerance.
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IAEA Safety Guides NS-R-1 and NS-G-1.3 – Provide international guidance on safety requirements and operational practices for nuclear power plants, harmonized with IEC 60671.
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IEC 60880 and IEC 62138 – Additional standards covering software and hardware requirements for digital safety I&C systems in nuclear facilities.
By adhering to IEC 60671:2007 alongside these standards, nuclear facilities can implement comprehensive safety surveillance programs that enable continuous verification of instrumentation and control functions vital to reactor safety.
Keywords: IEC 60671:2007, nuclear power plant safety, instrumentation and control systems, surveillance testing, safety-critical systems, IEC 61226, I&C self-supervision, functional testing, nuclear instrumentation standards, safety function monitoring, reactor safety instrumentation.