IEC TR 62096:2009

Nuclear power plants - Instrumentation and control important to safety - Guidance for the decision on modernization

IEC/TR 62096:2009 is intended to support owners of a nuclear power plant in the decision-making process and in the preparation for partial or complete modernization of the I&C. For this, it provides a summary of the motivating factors for I&C modernization, the principal options for the elaboration of different scenarios for I&C modernization, the technical and economic criteria for the selection of a long term I&C strategy, the principal aspects to be taken into account for a detailed technical feasibility study. This new edition includes the following significant technical changes with respect to the previous edition:
- update on references, taking into account standards published since the previous edition;
- update on the terminology, incorporation of a number of clarifications proposed by National Committees.

Centrales nucléaires de puissance - Instrumentation et contrôle-commande importants pour la sûreté - Guide pour décider d'une modernisation

La CEI/TR 62096:2009 est destinée à aider les propriétaires de centrales nucléaires lors du processus décisionnel et pendant la préparation de la modernisation partielle ou totale de l'I&C. Pour cela, il propose un rappel des facteurs motivant une modernisation de l'I&C, les principales options pour l'élaboration de différent scénarios de modernisation de l'I&C, les critères économiques et techniques pour le choix d'une stratégie d'I&C à long terme, les principaux aspects à prendre en compte dans une étude de faisabilité technique détaillée. Cette nouvelle édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- mise à jour des références en prenant en compte les normes publiées depuis la publication de l'édition précédente,
- mise à jour de la terminologie, prise en compte d'un certain de nombre d'éclaircissements proposés par les Comités Nationaux.

General Information

• Status: Published
• Publication Date: 23-Mar-2009
• ICS: 17.200.20 - Temperature-measuring instruments
• ICS: 27.120.10 - Reactor engineering
• ICS: 27.120.20 - Nuclear power plants. Safety
• Technical Committee: SC 45A - Instrumentation, control and electrical power systems of nuclear facilities
• Drafting Committee: WG 10 - TC 45/SC 45A/WG 10
• Current Stage: PPUB - Publication issued
• Start Date: 24-Mar-2009
• Completion Date: 15-Jun-2009

Relations

• Revises: IEC TR 62096:2002 - Nuclear power plants - Instrumentation and control - Guidance for the decision on modernization
• Effective Date: 05-Sep-2023

Overview

IEC TR 62096:2009 is a comprehensive technical report published by the International Electrotechnical Commission (IEC) that provides guidance for decision-making on the modernization of Instrumentation and Control (I&C) systems important to safety in nuclear power plants. This standard is instrumental for nuclear power plant owners and operators, aiming to assist them in effectively planning and executing partial or complete modernization of I&C systems, ensuring safety, reliability, and regulatory compliance.

The report summarizes the motivations behind I&C modernization, outlines principal modernization options, presents criteria to select a long-term strategy, and highlights essential aspects of technical feasibility studies. Updated references, clarified terminology, and alignment with the latest IEC/ISO directives make this edition relevant for current and future modernization projects in the nuclear energy sector.

Key Topics

• Motivation for Modernization
  The standard addresses both economic and safety factors driving I&C modernization. Economic drivers include cost reductions and revenue improvements, while safety drivers focus on system reliability, regulatory compliance, and risk mitigation.

• Modernization Decision Process
  Guidance covers the entire decision lifecycle, including:

  • Assessment of I&C system life cycle phases
  • Development of long-term I&C strategies
  • Preliminary evaluations and priority setting for system upgrades
  • Budget considerations and identification of feasible modernization scenarios

• Feasibility Studies
  The report emphasizes detailed feasibility analyses that include:

  • Plant-specific preconditions and goals
  • Licensing and regulatory requirements
  • Budget estimation and implementation strategies
  • Documentation review and preparation of functional specifications
  • Human-machine interface (HMI) considerations and data management

• Technical and Regulatory Considerations
  Important factors addressed are:

  • Technology evolution and equipment availability
  • Company policies and engineering standards
  • Safety classifications and qualification requirements for hardware and software
  • Risk-benefit analysis including Defence-in-Depth and Diversity (3D) analysis
  • Fire and flood protection, response time, and uncertainty management
  • Documentation management, training, and staff qualification
  • Configuration management and interface integration with existing systems

• Implementation and Project Management
  Detailed recommendations on target architecture, sequencing of upgrade steps, work package definition, and strategies for equipment replacement during plant operation.

Applications

IEC TR 62096:2009 serves as an essential resource for:

• Nuclear power plant operators and owners aiming to maintain or improve the safety and reliability of their I&C systems while managing modernization costs.

• Engineering and project management teams involved in the planning and execution of I&C modernization projects, helping them develop practical strategies, risk assessments, and compliance frameworks.

• Regulatory bodies and safety authorities interested in understanding best practices and decision criteria for safely modernizing I&C systems essential to nuclear power plant operations.

• Consultants and system integrators specializing in nuclear I&C systems, who require a structured approach aligned with international standards for offering modernization solutions.

Related Standards

IEC TR 62096:2009 complements a family of IEC and ISO standards focused on nuclear instrumentation and safety, such as:

• IEC 61513 – Nuclear power plants – Instrumentation and control systems important to safety – General requirements for system design.

• IEC 60880 – Software for computer-based systems performing category A functions in nuclear power plants.

• IEC 62138 – Nuclear power plants – Instrumentation and control important to safety – Classification of systems and components.

• ISO/IEC Directives Part 2 – Rules for structure, drafting and presentation of IEC and ISO standards and reports.

Utilizing IEC TR 62096 alongside these standards ensures a holistic approach to modernization, addressing both technical and regulatory challenges critical to nuclear safety.

---

Keywords: IEC TR 62096, nuclear power plants, instrumentation and control, I&C modernization, nuclear safety, feasibility study, long-term I&C strategy, risk analysis, Defence-in-Depth, nuclear regulatory compliance, equipment qualification, human-machine interface, project management in nuclear energy.

Standards Content (Sample)

IEC/TR 62096 ®
Edition 2.0 2009-03
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Nuclear power plants – Instrumentation and control important to safety –
Guidance for the decision on modernization

Centrales nucléaires de puissance – Instrumentation et contrôle-commande
importants pour la sûreté – Guide pour décider d'une modernisation

IEC/TR 62096:2009
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IEC/TR 62096 ®
Edition 2.0 2009-03
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Nuclear power plants – Instrumentation and control important to safety –
Guidance for the decision on modernization

Centrales nucléaires de puissance – Instrumentation et contrôle-commande
importants pour la sûreté – Guide pour décider d'une modernisation

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XA
CODE PRIX
ICS 27.120.20 ISBN 978-2-88910-618-9
– 2 – TR 62096 © IEC:2009
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope and object.8
2 Normative references .8
3 Terms and definitions .9
4 Abbreviations .11
5 Motivation for modernization.12
5.1 General .12
5.2 Economic motivating factors.12
5.2.1 General .12
5.2.2 Cost reductions .12
5.2.3 Revenue.13
5.2.4 Economically motivated modernization .13
5.3 Safety motivating factors .14
5.4 Summary of motivations for modernization .14
6 Modernization decision overview .14
6.1 I&C life cycle .14
6.2 Long-term I&C strategy .17
6.2.1 General .17
6.2.2 Preliminary evaluation of I&C systems status and future needs .17
6.2.3 Renewing/upgrade priority for I&C systems .18
6.2.4 Budget boundary conditions .18
6.2.5 Evaluation of different modernization scenarios .18
6.3 Feasibility studies.19
6.3.1 General .19
6.3.2 Evaluation of plant related preconditions and goals .19
6.3.3 Licensing.20
6.3.4 Preliminary budget costs .21
6.3.5 Implementation strategy .21
6.3.6 Evaluation of as-built documentation .22
6.3.7 Basic requirement specification .23
6.3.8 Function allocation .24
6.3.9 Function and task analysis for the HMI .24
6.3.10 Data management .25
6.3.11 Design tools .25
6.4 Tender specification and purchasing of the individual systems .26
6.4.1 General .26
6.4.2 Specification of I&C system properties for candidate solutions .26
6.4.3 Specification of requirements for quotations .27
6.4.4 Tenders for each system .27
6.4.5 Order placement.27
7 Considerations for modernization .28
7.1 General .28
7.2 Technology considerations .28
7.3 Economic considerations.29
7.4 Regulatory codes and standards .30

TR 62096 © IEC:2009 – 3 –
7.5 Company policy and engineering standards.30
7.6 Safety and process control system future needs.30
7.7 I&C system reliability.32
7.8 Risks and benefit study .32
7.9 Safety classification .33
7.10 Equipment qualification requirements .33
7.11 Software qualification requirements.34
7.12 Physical constraints .35
7.13 Equipment availability (delivery and support).35
7.14 Human factors.35
7.15 Defence-in-Depth and Diversity analysis (3D analysis) .37
7.16 Separation and protection against fire and flooding .38
7.17 Uncertainty and set point calculation .38
7.18 Response time analysis.38
7.19 Test procedures .38
7.20 Documentation management .39
7.21 Update of plant technical documentation .40
7.22 Training and staff qualification.40
7.23 Project organization .41
7.24 Configuration management.41
7.25 Interfaces to the other existing systems.41
7.26 Standardisation .42
8 Implementation.42
8.1 General remarks.42
8.2 Target architecture .42
8.3 Sequence of upgrading steps .43
8.3.1 General .43
8.3.2 One large versus several small work packages.44
8.3.3 Definition of work packages.44
8.3.4 Parallel operation and replacing equipment at power.45
8.3.5 Sequence of work packages .45
9 Recommendations.46
Bibliography.48

Figure 1 – IEC 62096 structure .8

Table 1 – I&C life cycle phases.16

– 4 – TR 62096 © IEC:2009
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL IMPORTANT TO SAFETY –
GUIDANCE FOR THE DECISION ON MODERNIZATION

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62096, which is a technical report, has been prepared by subcommittee 45A:
Instrumentation and control of nuclear facilities, of IEC technical committee 45: Nuclear
instrumentation.
This second edition cancels and replaces the first edition published in 2002.
This edition includes the following significant technical changes with respect to the previous
edition:
– update on the format to align with the current IEC/ISO directives on style of documents;
– update on references, taking into account Standards published since the first edition;
– update on the terminology;
TR 62096 © IEC:2009 – 5 –
– incorporation of a number of clarifications proposed by National Committees.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
45A/711/DTR 45A/726/RVC
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – TR 62096 © IEC:2009
INTRODUCTION
a) Technical background, main issues and organisation of this Technical Report
Normal procedures for evaluation of plant safety, operations and maintenance provide
information about potential needs for renewal or upgrades. After many years of operation, the
Instrumentation & Control (I&C) systems may no longer fulfil actual or anticipated safety
requirements, may be obsolete or unreliable, or may no longer be fit for required lifetime
extensions. In such cases, modernization provides the way forward to adapt the I&C systems
to meet the requirements or to deal with the problems and costs caused by the obsolescence
or aging of the equipment. During modernization, the benefits offered by modern I&C
equipment can be evaluated.
It is intended that this Technical Report be used by operators of NPPs (utilities), systems
evaluators and by licensors.
b) Situation of the current Technical Report in the structure of the IEC SC 45A
standard series
IEC 62096, as a Technical Report, is the fourth level IEC SC 45A document tackling the issue
of guidance for decision for modernisation.
For more details on the structure of the IEC SC 45A standard series, see d) of this
introduction.
c) Recommendations and limitations regarding the application of this Technical
Report
There are no particular recommendations, neither limitations regarding the use of this
Technical Report.
d) Description of the structure of the IEC SC 45A standard series and relationships
with other IEC documents and other bodies’ documents (IAEA, ISO)
The top-level document of the IEC SC 45A standard series is IEC 61513. It provides general
requirements for I&C systems and equipment that are used to perform functions important to
safety in NPPs. IEC 61513 structures the IEC SC 45A standard series.
IEC 61513 refers directly to other IEC SC 45A standards for general topics related to
categorization of functions and classification of systems, qualification, separation of systems,
defence against common cause failure, software aspects of computer-based systems,
hardware aspects of computer-based systems, and control room design. The standards
referenced directly at this second level should be considered together with IEC 61513 as a
consistent document set.
At a third level, IEC SC 45A standards not directly referenced by IEC 61513 are standards
related to specific equipment, technical methods, or specific activities. Usually these
documents, which make reference to second-level documents for general topics, can be used
on their own.
A fourth level extending the IEC SC 45A standard series, corresponds to the technical reports
which are not normative.
IEC 61513 has adopted a presentation format similar to the basic safety publication
IEC 61508 with an overall safety life-cycle framework and a system life-cycle framework and
provides an interpretation of the general requirements of IEC 61508-1, IEC 61508-2 and
IEC 61508-4, for the nuclear application sector. Compliance with IEC 61513 will facilitate

TR 62096 © IEC:2009 – 7 –
consistency with the requirements of IEC 61508 as they have been interpreted for the nuclear
industry. In this framework, IEC 60880 and IEC 62138 correspond to IEC 61508-3 for the
nuclear application sector.
IEC 61513 refers to ISO standards, as well as to IAEA 50-C-QA (now replaced by IAEA GS-R-
3) for topics related to quality assurance (QA).
The IEC SC 45A standards series consistently implements and details the principles and
basic safety aspects provided in the IAEA code on the safety of NPPs and in the IAEA safety
series, in particular the Requirements NS-R-1, establishing safety requirements related to the
design of Nuclear Power Plants, and the Safety Guide NS-G-1.3 dealing with instrumentation
and control systems important to safety in Nuclear Power Plants. The terminology and
definitions used by SC 45A standards are consistent with those used by the IAEA.

– 8 – TR 62096 © IEC:2009
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL IMPORTANT TO SAFETY –
GUIDANCE FOR THE DECISION ON MODERNIZATION

1 Scope and object
This technical report is intended to support owners of an NPP in the decision-making process
and in the preparation for partial or complete modernization of the I&C. For this, it provides:
– a summary of the motivating factors for I&C modernization,
– the principal options for the elaboration of different scenarios for I&C modernization,
– the technical and economic criteria for the selection of a long term I&C strategy,
– the principal aspects to be taken into account for a detailed technical feasibility study.
In addition, this report contains detailed recommendations and practical advice for:
– the technical evaluation of the actual status of the I&C systems,
– the content of the I&C system requirement specification and for the project management
following the guidance given in IAEA TECDOC 1016 and 1066,
– considerations on modernization strategy.
Special attention is paid to the improvement of reactor safety and of the human machine
interface. The report does not provide I&C design requirements. For these it is assumed that
the IAEA Codes and Guides are used as top level documents while IEC publications are
mainly used for system design, requirements on equipment and some work methods. IAEA
Reports and other documents are referenced to give information that is more detailed on
specific areas.
The structure of the report is given in Figure 1. The recommended sequence is, first, to
summarize the more easily obtained motivations (Clause 5) and then establish a project that
works in structured and more and more detailed steps: Long term I&C strategy – Feasibility
studies – Tender specification and order (Clause 6). Clauses 7 and 8 may be used as
checklists during each step.
Clause 5 Motivation for upgrading
Subclause 6.1 I and C life cycle Clause 7
Clause 8 Subclause 6.2 Long term I and C strategy Considerations for
Implementation Subclause 6.3 Feasibility studies modernization
Subclause 6.4 Tender specification
decision, order
IEC  437/09
Figure 1 – IEC 62096 structure
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.

TR 62096 © IEC:2009 – 9 –
IEC 60050-191:1990, International Electrotechnical Vocabulary – Chapter 191: Dependability
and quality of service
IEC 60300-3-3:2004, Dependability management – Part 3-3: Application guide – Life cycle
costing
IEC 60709, Nuclear power plants – Instrumentation and control systems important to safety –
Separation
IEC 60880:2006, Nuclear power plants – Instrumentation and control systems important to
safety – Software aspects for computer-based systems performing category A functions
IEC 60964:2009, Nuclear Power Plants – Control rooms – Design
IEC 61513, Nuclear power plants – Instrumentation and control for systems important to
safety – General requirements for systems
IEC 61839, Nuclear power plants – Design of control rooms – Functional analysis and
assignment
IEC 61888, Nuclear power plants – Instrumentation important to safety – Determination and
maintenance of trip setpoints
IEC 62241, Nuclear power plants – Main control room – Alarm functions and presentation
IEC 62342:2007, Nuclear power plants – Instrumentation and control systems important to
safety – Management of ageing
IAEA-TECDOC-1066:1999, Specification of requirements for upgrades using digital instrument
and control systems (only available in English)
IAEA-TECDOC 1147:2000, Management of aging of I&C equipment in nuclear power plants
(only available in English)
IAEA:2007, IAEA safety glossary terminology used in nuclear safety and radiation protection
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
availability
the ability of an item to be in a state to perform a required function under given conditions at a
given instant of time or over a given time interval, assuming that the required external
resources are provided
[IEV 191-02-05]
NOTE This ability depends on the combined aspects of the reliability performance, the maintainability
performance and the maintenance support performance.
3.2
configuration management
the process of identifying and documenting the characteristics of a facility’s structures,
systems and components (including computer systems and software), and of ensuring that
changes to these characteristics are properly developed, assessed, approved, issued,
implemented, verified, recorded and incorporated into the facility documentation

– 10 – TR 62096 © IEC:2009
[IAEA Safety Glossary, 2007]
3.3
Human Machine Interface
the interface between operating staff and I&C system and computer systems linked with the
plant. The interface includes displays, controls, and the Operator Support System interface
[IEC 60964, 3.13]
3.4
I&C system
system, based on electrical and/or electronic and/or programmable electronic technology,
performing I&C functions as well as service and monitoring functions related to the operation
of the system itself
The term is used as a general term which encompasses all elements of the system such as
internal power supplies, sensors and other input devices, data highways and other
communication paths, interfaces to actuators and other output devices. The different functions
within a system may use dedicated or shared resources
[IEC 60964, 3.14]
3.5
life cycle
time interval between a product’s conception and its disposal
[IEC 60300-3-3, 3.1]
3.6
life cycle cost
cumulative cost of product over its life cycle
[IEC 60300-3-3, 3.3]
3.7
maintainability
probability that a given active maintenance action, for an item under given conditions of use
can be carried out within a stated time interval, when the maintenance is performed under
stated conditions and using stated procedures and resources.
[IEV 191-02-07, modified]
3.8
modernization
replacement or upgrading with newer systems and components. Replacement is the term to
be used when there is no change in requirements; upgrading is the term to be used when the
level of requirements increases
NOTE 1 Backfit, refit, retrofit, refurbish and upgrade are similar terms which are often used interchangeably –
They only differ in shades of meaning (IAEA-TECDOC-1066).Upgrading also includes the implementation of new
functionality.
NOTE 2 Replace and renew are similar and often interchangeable. The terms are used from a single component
up to the complete I&C.
[IEC 62342, 3.10]
3.9
nuclear safety
achievement of proper operating conditions, prevention of accidents or mitigation of accident
consequences, resulting in protection of workers, the public and the environment from undue
radiation hazards
TR 62096 © IEC:2009 – 11 –
NOTE Often abbreviated to safety in Agency publications on nuclear safety, particularly when other types of
safety (e.g. fire safety, conventional industrial safety) are being discussed.
[IAEA Safety Glossary, 2007]
3.10
requirements
expression in the content of a document conveying criteria to be fufilled if compliance with the
document is to be claimed and from which no deviation is permitted
[ISO/IEC Directives, part 2, 2004, 3.12.1]
NOTE 1 In IEC/SC 45A documents the following types of requirement are distinguished:
Safety requirements – Requirements imposed by authorities on the safety of the NPP in terms of impact on
individuals, society and environment during the NPP lifecycle.
Functional and performance requirements – Functional requirements state what actions the system must take in
response to specific signals or conditions, and performance requirements define features such as response times
and accuracy.
Operational requirements – Requirements on the operational capacity and ability of the plant imposed by the
owner.
Plant design requirements – Technical requirements on plant general design for the fulfillment of the safety
requirements and operational requirements on the plant.
System design requirements – Design requirements on individual systems to give a design of the complete plant
fulfilling the plant design requirements.
Equipment requirements – Requirements on individual equipment for its fulfillment of the demands of the system
design.
NOTE 2 The IAEA Safety glossary (2007) contains the following definition:
Required, requirement – Required by (national or international) law or regulations, or by IAEA Safety Fundamentals
or Safety requirements.
The requirements aimed at by this IAEA definition are the same designated by the IEC/SC 45A definition "Safety
requirement".
3.11
specification
document that specifies, in a complete, precise, verifiable manner, the requirements, design,
behaviour, or other characteristics of a system or component and, often the procedures for
determining whether these provisions have been satisfied
[IEC 60880, 3.39]
4 Abbreviations
CAD Computer Aided Design
CDF Core Damage Frequency
CMF Common Mode Failure
DBA Design Basis Accident
DCS Distributed Control System
EMC Electromagnetic Compatibility
EMI Electromagnetic Interference

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FAT Factory Acceptance Tests
HMI Human Machine Interface
I/O Input/Output
I&C Instrumentation & Control
LOCA Loss Of Coolant Accident
O&M Operation & Maintenance
PAM Post Accident Monitoring
PLC Programable Logic Controller
PSA Probabilistic Safety Assessment
SAT Site Acceptance Tests
SCC Station Control Computer
SW V&V Software Verification&Validation
VDU Visual Display Unit
3D analysis Defence-in-Depth and Diversity analysis
5 Motivation for modernization
5.1 General
The motivating factors for modernization can be considered under two headings according to
the main benefits: economic and safety. The replacement of I&C equipment with a more
modern equivalent usually leads to increased functionality and performance improvements,
but it is likely that most upgrades are primarily motivated by problems with the old equipment
rather than the perceived benefits of the new.
5.2 Economic motivating factors
5.2.1 General
The economic yield should be optimised using a life-cycle costing approach, taking into
account not only lower costs but also increased production.
5.2.2 Cost reductions
Cost reductions can be achieved in the following areas:
– Operating costs can be reduced through efficiency improvements leading to savings in
fuel, power consumption, consumables, or operational manpower requirements.
– Maintenance costs can be reduced by extending maintenance intervals and/or reducing
the time and effort required for maintenance tasks. Improvements in the reliability of
equipment reduce the cost of repair work and spares inventory. Also the reduction of the
number of equipment families by the use of a single system platform may lead to a

TR 62096 © IEC:2009 – 13 –
reduced spare parts inventory. In some cases, high redundancy design can allow
preventive maintenance during normal operation.
– Administration costs can be reduced through improvements in the way in which
information is collected, processed, stored, and presented.
Cost reductions should be considered using a life-cycle costing approach focused on
minimizing the total cost of the system over its intended life cycle. Note that a modernization
with an expensive type of component with high reliability may increase the procurement cost
but reduce the long-term support cost, and may give the lowest overall life cycle cost.
5.2.3 Revenue
Revenue can be increased in the following ways:
– Higher generation level
Improvements in monitoring and protection systems can give greater confidence in plant
status, allowing reduction of safety margins at the same plant safety level and more power
output.
– Increased availability
Shorter shutdowns for repairs, routine maintenance and fuelling, and a lower probability of
spurious trips result in better plant utilisation. This can be achieved through improvements
in reliability and stability, and through the use of ‘smart’ systems with capabilities for self-
checking, diagnostics and auto-calibration, and improved operator support by HMI and
I&C functions. The upgrading of obsolete equipment reduces the probability of a prolonged
shutdown due to the unavailability of replacement parts.
– Increased plant lifetime
If the operation of the plant can be extended beyond its planned economic lifetime, there
is a considerable benefit in accounting terms, because the revenue is no longer offset by
capital charges. It is necessary to modernize any equipment or systems whose predicted
residual life will be insufficient for the planned plant life extension.
5.2.4 Economically motivated modernization
Economically motivated modernization may be initiated by one or more of the following
factors:
– Obsolescence
Equipment obsolescence occurs towards the end of a product’s life cycle. When an item of
equipment is no longer in production, the level of service available from the manufacturer
decreases, and spare parts and consumables become unavailable or unacceptably
expensive. Obsolescence also occurs at the electronic component level, where life cycles
can be as short as a few years.
The initial effect of obsolescence is to increase timescales and costs for maintenance and
repair work. Ultimately the equipment will be rendered unserviceable by the non-
availability of spare parts.
– Competence of personnel
A related problem is the decreasing availability of suitably skilled maintenance personnel.
Recently trained personnel do not have the required skills for analogue electronics.
Technical education and training courses tend to concentrate on digital technology.
– Aging
The aging effects suffered by electronic components and assemblies can lead to problems
with noise, drift, response time, EMI susceptibility, and general reduced reliability.
Examples of degradation due to aging include:
– chemical effects such as oxidation or corrosion, which lead to high resistance contacts
in connectors, switches and solder joints,
– drying out of electrolytic capacitors,

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– loss of insulation due to the build-up of surface contamination (particularly in high-
voltage equipment),
– cables and other components made from organic material are subject to aging effects
(e.g. embrittlement) when exposed to temperature, radiation, oxygen, etc,
– mechanical effects such as wear, seizure, and loss of spring tension, all of which
eventually lead to the failure of mechanisms in switches, connectors, relays, etc.
– Compatibility issues
It is sometimes necessary to upgrade equipment which would otherwise be considered
satisfactory because of the effects of changes elsewhere. The following are examples of
compatibility issues:
– changes to reactor or process equipment resulting in differing I&C requirements,
– changes to other I&C equipment using newer interfacing connections or protocols.
– Operational issues
I&C modernisation may become necessary to implement changes in operational
requirements, such as a change from ‘base load’ to ‘load following’.
5.3 Safety motivating factors
A safety improvement upgrade may become necessary to comply with regulatory
requirements. Such an upgrade may have a significant cost and no apparent economic
benefits. Nevertheless, the decision is ultimately an economic one where the plant owner
should compare the costs of performing the upgrade versus the costs associated with
operating restrictions on the plant.
Safety improvement upgrades may be initiated by one or more of the following:
– recommendations of a safety review,
– changes in licensing requirements,
– deficiencies revealed by an incident or reportable occurrence,
– deficiencies revealed by testing.
5.4 Summary of motivations for modernization
A report should be written summarizing the various aspects of modernization for use in the
decision on future actions. Where possible, the report includes a cost benefit analysis where
each argument can be quantified. Clause 7 may be used as a checklist for defining the most
important aspects. When a decision is taken to investigate and define a modernization, the
I&C lifecycle description in Clause 6 should be followed.
6 Modernization decision overview
6.1 I&C life cycle
A reference life cycle should be established for the modernization project, and a suggested
outline for a lifecycle is given by Table 1.
Based on the input from Clause 5 on motivation for modernization this subclause focuses on
the life cycle for modernization. With reference to the IAEA-TECDOC-1066, which mainly
addresses the potential suppliers of nuclear plant services, this technical report addresses
just those life cycle phases which require specific activities from the NPP utilities. Table 1
gives in close co-relation to IAEA-TECDOC-1066 an overview of all life cycle phases of I&C
systems.
This subclause focuses on the phases which determine the strategy for modernization and the
tender process up to the point where any necessary new equipment or plant I&C changes are
ordered (1 to 3 in Table 1). The life cycle phases described are:

TR 62096 © IEC:2009 – 15 –
– 6.2 Long- term I&C strategy,
– 6.3 Feasibility studies,
– 6.4 Tender specification and purchasing of the individual systems.
In Clause 7, Considerations for modernization, and clause 8, Implementation, more details
are described for use when applicable in the appropriate subclauses .

IEC/TR 62096
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Table 1 – I&C life cycle phases
(see also Table XI of IAEA-TECDOC-1066)
I&C life cycle phases
Generic modernization strategy Relating actions, results, plans
1 Long-term I&C strategy Evaluation of I&C systems status
to meet the needs for plant operation Renewing/upgrade priorities
Budgetary boundary conditions
Different modernization scenarios
2 Feasibility studies A. Generic feasibility studies
– Plant related preconditions and goals
– Licensing
– Preliminary budget costs
– Implementation strategy
– I&C architecture
– Sequence of modernization steps
B. Studies of technical feasibility aspects
– Evaluation of as-built documentation
– Basic requirements specification
– Function allocation
– Function and task analysis for HMI
– Data collection and design goals
Modernization phases of individual systems Relating actions
3 Tender specification and purchasing of Specification of I&C properties
individual systems or complete I&C
Specification of requirements
Suppliers’ tenders
Order to the supplier
4 Specification of the individual I&C systems Validated specification and plans on:
System validation (FAT & SAT)
System operation and maintenance
Staff training
5 System realization Detailed manufacturing and installation documentation and
operating and maintenance manuals
Detail design of individual I&C systems
System ready for tests
Manufacturing and system integration
6 Factory acceptance test (FAT) System ready for shipment to site
FAT test report
Plant related phases
7 Installation and setting to work of the individual Start of system failure reporting
systems
TR 62096 © IEC:2009 – 17 –
Table 1 (continued)
I&C life cycle phases
8 Training and contractual documents All contractual documents provided
9 Site acceptance test (SAT) and commissioning System ready for operation
with plant
SAT test report
10 Operation and maintenance Continued system failure reporting
Reporting of the result of routine tests
Simulator upgrading
Operator training
11 Decommissioning Decommissioning plans
...