1.1 General<\/b><\/p>\n
This document is applicable to nuclear power plant instrumentation and control (I&C) and electrical systems and equipment, whose functions are required to be independent due to their contribution to:<\/p>\n
a redundant or diverse safety group;<\/p>\n<\/li>\n
different defence in depth levels;<\/p>\n<\/li>\n
different safety classes and also with non-classified (NC) systems.<\/p>\n<\/li>\n<\/ul>\n
It is also applicable to temporary installations which are part of those I&C and electrical systems important to safety (for example, auxiliary equipment for commissioning tests and experiments or mobile power supply systems). Clause 7 is intended particularly for electrical isolation, Clause 8 is intended particularly for the cabling and the arrangement of equipment of I&C and electrical systems important to safety.<\/p>\n
This document applies to I&C and electrical systems of new nuclear power plants and to I&C and electrical upgrading or back-fitting of existing plants. For existing plants see 1.2 and 5.4.<\/p>\n
Where independence is required by general safety standards such as IAEA safety guides, IEC 61513 (for I&C), IEC 63046 (for electrical systems) and other project constraints, one aspect of achieving this independence is physical separation and electrical isolation between the systems and their equipment that perform safety functions. This document defines the assessments needed and the technical requirements to be met for I&C and electrical systems, equipment or cables for which separation is required. Those means are to achieve adequate physical separation and electrical isolation between redundant sections of a system and between a higher and lower class systems. 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.<\/p>\n
The requirements for functions, and their associated systems and equipment, to be independent are normally defined in detail in the project documentation; the method of determining and defining these requirements is not the subject of this document.<\/p>\n
Following IAEA SSR-2\/1 Requirement 21, separation means by physical separation, electrical isolation, functional independence and independence of communication are considered. In this document physical separation and electrical isolation are treated. Functional independence and independence of communication are not considered in this document. More details referring to functional independence, independence from control systems and independence of communication are given in Annex D.<\/p>\n
1.2 Application: new and pre-existing plants<\/b><\/p>\n
This document applies to the I&C and electrical of new nuclear power plants as well as to up-grading or back-fitting of existing plants.<\/p>\n
For existing plants, only a subset of requirements is applicable and this subset is normally specified and argued at the beginning of any project.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 1 Scope 1.1 General 1.2 Application: new and pre-existing plants <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 2 Normative references <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 4 Abbreviated terms <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 5 Principles and requirements for separation 5.1 Principles 5.1.1 General 5.1.2 Separation reasoning and boundaries <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 5.1.3 Plant safety principles and requirements 5.2 Safety class separation requirements Figures Figure 1 \u2013 Physical separation by structure or distance Figure 2 \u2013 Separation by electrical isolation <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 5.3 Associated circuits 5.3.1 General <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 5.3.2 Criteria <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 5.4 Separation issues at existing plants 5.4.1 General 5.4.2 Criteria 6 Separation design basis 6.1 Design inputs <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 6.2 Environmental conditions and hazards 6.2.1 General 6.2.2 Environmental conditions 6.2.3 External hazards 6.2.4 Internal hazards <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 6.2.5 Fire protection 6.3 EMI\/EMC 6.4 Electrical fault 6.5 Requirements from non-nuclear technical standards 6.6 Requirements from special operating conditions <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | 7 Electrical isolation 7.1 Principles 7.1.1 General 7.1.2 Overvoltage barrier 7.1.3 Short circuit \/ Overcurrent protection Figure 3 \u2013 Electrical Isolation measures and selection of components <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | 7.1.4 Electrical nonreactive (retroaction free) 7.1.5 Galvanic isolation (electrical insulation) 7.2 Isolation devices 7.2.1 General <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 7.2.2 Isolation characteristics 7.2.3 Actuation priority <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 8 Physical separation 8.1 Principles 8.1.1 General 8.1.2 Separation by distance 8.1.3 Structural separation 8.2 Separation of cables and cable support structures 8.2.1 General <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 8.2.2 Divisional separation of redundant cables and cable support structures 8.2.3 Separation of system cables and cable supporting structures of different safety classes <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | 8.2.4 Separation of signal cables from power cables 8.2.5 Reduced separation distances 8.2.6 Associated circuits 8.2.7 Separation of cables from tubes or pipes 8.2.8 General routing considerations 8.2.9 Identification 8.3 Separation of components inside the I&C and electrical system important to safety 8.3.1 Divisional separation of redundant components inside the I&C and electrical system important to safety <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | 8.3.2 Separation of components of different safety classes 8.3.3 Installation of equipment of different voltage levels 8.3.4 Reduced separation distances <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | 8.3.5 Associated circuits 8.3.6 Separation of components from sources of hazards 8.4 Control room cabinets, desks, panels and related cables <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | 9 Verification <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Annex A (normative) Relation to IAEA guidelines and IEC 61226 A.1 Object of this Annex A.2 Applicability of this document A.3 IAEA Guidelines, applicable for this document A.4 IEC standards, applicable for the safety categorization and classification <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | A.5 Defence in Depth levels, simplified definitions <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Annex B (informative) Examples of separation realizations B.1 Object of this Annex B.2 Example of physical separation B.2.1 General B.2.2 Examples of physical separation by distance <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | Figure B.1 \u2013 Separation of cable supporting structures by distance Figure B.2 \u2013 Separation of cable trays by distance <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | B.2.3 Examples of physical separation by structure Figure B.3 \u2013 Separation by structures <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | B.3 Example of electrical isolation B.3.1 General B.3.2 Examples of overvoltage barriers Figure B.4 \u2013 Overvoltage barriers in I&C systems <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | B.3.3 Examples of short circuit \/ overcurrent protection Figure B.5 \u2013 Overvoltage protection in electrical systems <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | B.3.4 Examples of galvanic isolation Figure B.6 \u2013 Short circuit protection in case of a cross-connection Figure B.7 \u2013 Galvanic isolation in I&C systems <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | B.4 Example of EMC protection Figure B.8 \u2013 Galvanic isolation in electrical systems <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | B.5 Associated circuits Figure B.9 \u2013 EMC protection of I&C cables <\/td>\n<\/tr>\n | ||||||
| 47<\/td>\n | Figure B.10 \u2013 Examples of associated circuits <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | Annex C (informative) Examples of design errors and I&C and electrical failure events C.1 Object of this Annex C.2 Design errors C.3 I&C and electrical system failure events C.3.1 General C.3.2 Single random failure C.3.3 Multiple failures from a single common cause <\/td>\n<\/tr>\n | ||||||
| 49<\/td>\n | Annex D (informative) Functional independence and independence of communication D.1 Object of this Annex D.2 Functional independence D.2.1 General D.2.2 Independence from control system <\/td>\n<\/tr>\n | ||||||
| 50<\/td>\n | D.3 Independence of communication <\/td>\n<\/tr>\n | ||||||
| 51<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Nuclear power plants. Instrumentation, control and electrical systems important to safety. Separation<\/b><\/p>\n |