BS EN IEC-60709-2019 pdf download.Nuclear power plants — Instrumentation and control systems important to safety — Separation.
This standard is applicable to nuclear power plant instrumentation and control (I&C) systems, and their cables, that are important to safety, as defined in IAEA Safety Guide NS-G-1.3. It is also applicable to temporary installations which are part of those I&C systems important to safety (for example, auxiliary equipment for commissioning tests and experiments). Clause 6 is intended particularly for the cabling of the I&C systems important to safety. This standard applies to the I&C of new nuclear power plants as well as to I&C upgrading or back-fitting of existing plants. For existing plants, only a subset of the requirements is applicable; this subset is to be identified at the beginning of any project. Where independence is required by general safety standards such as IAEA safety guides or IEC 61513, one aspect of achieving this independence is physical separation between the systems and their equipment that perform functions important to safety. This standard defines the assessments needed and the technical requirements to be met for I&C systems important to safety and their cables, in order to achieve adequate physical separation between redundant sections of a system and between a system and another system. This separation is needed to prevent or minimise the impact on safety that could result from faults and failures which could be propagated or affect several sections of a system or several systems.
2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60332 (all parts), Tests on electric cables under fire conditions
IEC 60964, Design for control rooms of nuclear power plants
IEC 61000 (all parts), Electromagnetic compatibility (EMC)
IEC 61000-6-5, Electromagnetic compatibility (EMC) – Part 6-5: Generic standards – Immunity for power station and substation environments
IEC 61226, Nuclear power plants – Instrumentation and control systems important for safety – Classification
IEC 61513, Nuclear power plants – Instrumentation and control for systems important to safety – General requirements for systems
IEC 62096, Nuclear power plants – Instrumentation and control – Guidance for the decision on modernisation
IAEA Safety Guide NS-G-1.3, Instrumentation and Control Systems Important to Safety in Nuclear Power Plants
3 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1 associated circuit
circuit of a lower safety category that is not physically separated or is not electrically isolated from the circuit(s) of the higher category by acceptable separation distances, safety class structures, barriers, or electrical isolation devices but meets suitable criteria for safety
3.2 barrier
device or structure interposed between redundant equipment or circuits important to safety, or between equipment or circuits important to safety and a potential source of damage to limit damage to the I&C system important to safety to an acceptable level
3.3 cable route
physical pathway through the plant along which multiple cables can be laid, such as through a room or duct in the plant building, or a metal duct, tray, or tube, or a duct below or gantry over roads
3.4 common cause failure (CCF)
failure of two or more structures, systems or components due to a single specific event or cause
[IAEA NS-G-1.3]
3.5 isolation device
device in a circuit that prevents malfunctions in one section of a circuit from causing unacceptable influences in other sections of the circuit or other circuits.BS EN IEC-60709 pdf download.