IEC 62340-2007 PDF

Full title and description

St IEC 62340-2007 — Nuclear power plants - Instrumentation and control systems important to safety - Requirements for coping with common cause failure (CCF). This international standard provides requirements and guidance to avoid and mitigate common cause failures affecting I&C systems that perform Category A (safety-critical) functions, and it recommends the implementation of independent I&C systems and the application of related safety principles.

Abstract

Gives requirements related to the avoidance of common cause failure (CCF) of instrumentation and control (I&C) systems performing category A functions in nuclear power plants. It also requires consideration of independent I&C systems to overcome CCF, and refers to the overall safety principles developed by IEC SC 45A (notably IEC 61226, IEC 61513, IEC 60880 and IEC 60709). The standard gives an overview of the complete scope of requirements relevant to CCF.

General information

• Status: Published — listed as current with a stability date to 2026 (no superseding edition published on the IEC webstore at the time of record).
• Publication date: 7 December 2007.
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 27.120.20 — Nuclear power plants. Safety.
• Edition / version: Edition 1.0 (2007).
• Number of pages: 46 pages.

Scope

Specifies requirements for avoidance, mitigation and management of common cause failures affecting safety-important I&C systems in nuclear power plants. The scope covers Category A functions and addresses design and implementation measures, independence of redundant systems, verification and assessment practices, and links to other SC 45A safety standards. It is intended to be used alongside IEC SC 45A standards that define system classification, architectural design requirements and verification methods.

Key topics and requirements

• Definition and classification of CCF mechanisms relevant to I&C systems performing Category A functions.
• Design principles to minimize likelihood of CCF (including diversity, independence and physical separation where appropriate).
• Requirements for implementing independent or diverse backup I&C systems to tolerate or recover from CCF.
• Requirements for analysis, testing, maintenance and assessment activities to detect or mitigate CCF vulnerabilities (including references to IEC 61226, IEC 61513, IEC 60880 and IEC 60709).
• Guidance on application of SC 45A overall safety principles and coordination with plant safety cases.

Typical use and users

Used by nuclear-power plant designers, I&C engineers, safety assessors, regulators and licensing bodies involved in specification, design review, verification and oversight of safety-important instrumentation and control systems. Also used by vendors of I&C equipment and consultants performing CCF analysis and safety justification.

Related standards

Closely related IEC SC 45A publications such as IEC 61226 (classification of I&C functions), IEC 61513 (general requirements for I&C systems important to safety), IEC 60880 (software aspects for computer-based systems) and IEC 60709, plus relevant nuclear safety guides (for example IAEA/ national guidance referenced in vendor and national adoptions). These documents are frequently used together to develop a complete safety demonstration for I&C CCF management.

Keywords

common cause failure, CCF, instrumentation and control, I&C, nuclear power plants, safety-critical, diversity, redundancy, independence, IEC SC 45A, IEC 62340:2007.

FAQ

Q: What is this standard?

A: IEC 62340:2007 is an international standard that specifies requirements for coping with common cause failures (CCF) in instrumentation and control systems important to safety in nuclear power plants.

Q: What does it cover?

A: It covers avoidance, mitigation and management measures for CCF affecting Category A (safety-critical) I&C functions, including requirements on independence, diversity and related verification and assessment activities; it also cross-references other SC 45A standards.

Q: Who typically uses it?

A: Plant designers, I&C engineers, regulators, safety assessors, licensing authorities, vendors and consultants working on safety-related I&C systems in nuclear facilities.

Q: Is it current or superseded?

A: IEC 62340 was published on 7 December 2007 and is shown on the IEC webstore with a stability date to 2026; the IEC entry does not indicate a later superseding edition at this time, so it remains the published edition until an updated replacement is issued. Users should always verify the current status with the IEC webstore or their national standards body before relying on the standard for compliance or design work.

Q: Is it part of a series?

A: It is part of the body of IEC SC 45A standards addressing instrumentation, control and electrical power systems of nuclear facilities and is intended to be used in conjunction with related IEC publications such as IEC 61226, IEC 61513, IEC 60880 and IEC 60709.

Q: What are the key keywords?

A: Common cause failure (CCF), I&C, nuclear safety, diversity, redundancy, independence, Category A functions, IEC SC 45A.