IEC 63351:2024

IEC 63351 ®
Edition 1.0 2024-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear facilities – Human factors engineering – Application to the design of
human-machine interfaces
Installations nucléaires – Ingénierie des facteurs humains – Application à la
conception des interfaces homme-machine

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IEC 63351 ®
Edition 1.0 2024-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear facilities – Human factors engineering – Application to the design of

human-machine interfaces
Installations nucléaires – Ingénierie des facteurs humains – Application à la

conception des interfaces homme-machine

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.120.20  ISBN 978-2-8322-9546-5

– 2 – IEC 63351:2024 © IEC 2024
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
3.1 Control locations . 11
3.2 Function, task and performance . 12
3.3 Human factors aspects . 13
3.4 Operational aspects . 14
3.5 Verification and validation . 16
4 Abbreviated terms . 17
5 Management of human factors engineering programme . 18
5.1 General . 18
5.2 Management arrangements . 19
5.3 Human factors engineering team . 20
5.3.1 HFE team responsibilities . 20
5.3.2 Support by a multidisciplinary team . 20
5.3.3 HFE team organisation, qualification and authorization . 21
5.4 Overall design process . 21
5.5 Identification and resolution of human engineering discrepancies (HEDs) . 23
5.6 HFE programme scope considerations . 23
5.6.1 General . 23
5.6.2 Integration of activities with the rest of plant facilities . 23
5.6.3 Screening of HFE elements . 23
5.6.4 Graded approach . 24
5.6.5 Use of reference designs . 24
5.6.6 Examples of application to different projects . 25
5.7 End point vision . 26
5.8 HFE deliverables to be prepared . 27
5.8.1 General . 27
5.8.2 HFE programme management . 27
5.8.3 Other HFE elements . 27
6 Analyses providing input to human interaction . 28
6.1 Operating experience review (OER) . 28
6.2 Functional analysis and assignment . 29
6.2.1 General . 29
6.2.2 Functional analysis . 29
6.2.3 Functional assignment . 29
6.2.4 Verification and re-evaluation of assignment . 29
6.2.5 Staff capabilities . 30
6.2.6 I&C system processing capabilities . 30
6.3 Identification and treatment of important human tasks . 30
6.3.1 General . 30
6.3.2 Identification of important human tasks . 31
6.3.3 Treatment of important human tasks . 31
6.3.4 Human reliability and safety analyses support . 32

6.4 Task analysis (TA) . 32
6.4.1 General . 32
6.4.2 Definition of the scope and screening criteria. 33
6.4.3 Development of task descriptions . 34
6.4.4 Breakdown tasks . 34
6.4.5 Specific task requirement identification . 35
6.4.6 Output and documentation . 35
6.5 Staffing, organisation, and qualification analysis . 35
6.5.1 General . 35
6.5.2 Inputs to staffing, organisation, and qualification analysis . 36
6.5.3 Methods used for staffing, organisation, and qualification analysis . 37
7 Design of control centres, local control points (LCPs), human-machine interfaces
(HMIs), procedures and training programmes . 37
7.1 General . 37
7.2 Design of control centres, LCPs and HMIs . 38
7.2.1 General . 38
7.2.2 HFE inputs to the design of control centres and HMIs . 39
7.3 Guidance for the design of control centres, LCPs and HMIs . 39
7.3.1 General . 39
7.3.2 Plant-specific HFE guidance . 39
7.3.3 Project-specific HFE guidance . 39
7.3.4 Guidance for the design of control centres . 40
7.3.5 Guidance for the design of local control points (LCPs) . 40
7.3.6 Guidance for the design of human-machine interfaces (HMIs) . 41
7.4 Development of procedures . 41
7.4.1 General . 41
7.4.2 Paper-based procedures vs. computer-based procedures (CBP) . 42
7.4.3 Procedures writers guide . 42
7.4.4 Other HFE inputs to procedure designers . 43
7.4.5 Procedures and multistage verification and validation (V&V) . 43
7.5 Development of operating staff training . 43
7.5.1 General . 43
7.5.2 Organisational aspects . 44
7.5.3 The inputs to implement a training programme provided by the HFE
team . 44
7.5.4 Training for teamwork . 44
8 Verification and validation . 45
8.1 General . 45
8.2 Verification and validation preparation . 45
8.3 Verification and validation execution . 47
8.3.1 Task support verification . 47
8.3.2 Design verification . 47
8.3.3 Preliminary validation . 48
8.3.4 Integrated system validation execution and resolution . 49
8.3.5 Verification and validation resolution . 50
9 HFE during implementation of the design . 50
9.1 Background. 50
9.2 Objectives . 51
9.3 Confirmation of the as built / implemented HMI . 51

– 4 – IEC 63351:2024 © IEC 2024
9.4 Monitoring and control of plant changes implementation . 52
10 Human performance monitoring . 53
10.1 Objective . 53
10.2 Process to be developed . 53
10.2.1 General . 53
10.2.2 Planning and administration . 53
10.2.3 Execution and evaluation . 54
10.2.4 Resolution . 54
Annex A (informative) Task analysis methods . 55
A.1 Walk-through / talk-through . 55
A.2 Hierarchical task analysis . 55
A.3 Operating sequence analysis . 56
A.4 Timeline analysis . 57
A.5 Cognitive task analysis . 58
A.6 Workload analysis . 58
Annex B (normative) Goals of HFE in the design of control centres and HMIs . 59
B.1 General . 59
B.2 HFE in the design of the control centres . 59
B.3 HFE in the design of the human-machine interfaces . 60
Annex C (informative) Validation methodological issues . 61
C.1 Overview. 61
C.2 General validation objectives . 61
C.3 Specific validation objectives . 62
C.4 ISV test design . 62
C.5 Performance measures . 63
C.6 Validation acceptance criteria . 64
C.7 Validation results, analysis and reporting . 64
C.8 Considerations related to ISV reporting and conclusions . 65
Bibliography . 66

Figure 1 – New WG 8 document structure . 8
Figure 2 – Human Factors Engineering process . 22
Figure A.1 – Example of HTA performed for a PWR NPP . 56
Figure A.2 – Example of OSA/OSD performed for a PWR NPP . 57

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR FACILITIES –
HUMAN FACTORS ENGINEERING –
APPLICATION TO THE DESIGN OF HUMAN-MACHINE INTERFACES

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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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IEC 63351 has been prepared by subcommittee 45A: Instrumentation, control and electrical
power systems of nuclear facilities, of IEC technical committee 45: Nuclear instrumentation. It
is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
45A/1530/FDIS 45A/1546/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

– 6 – IEC 63351:2024 © IEC 2024
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

INTRODUCTION
a) Technical background, main issues and organisation of the Standard
The technical background that led to the decision to develop this International Standard is given
in technical report IEC TR 63214.
In brief, IEC TR 63214 recognized that:
• IEC 60964 entitled "Control Room Design" (then at edition 2.0) included a detailed set of
requirements to be applied when designing a control room and a process to implement
Human Factors Engineering;
• The above two topics were mixed and the Human Factors part was incomplete and did not
reflect state-of-the-art knowledge and wording;
• IEC 60964 was also written considering only Human Factors within the scope of the I&C
systems in control room designs. The result was that the document did not take a holistic
approach towards the design of the plant-wide control rooms and human-machine interfaces
(HMI), including e.g. the local control stations located throughout the plant;
• In addition, the IAEA was in the process of developing a Human Factors Guide (now
published as SSG-51) that should also be reflected in the IEC standards.
In view of the above, IEC TR 63214 proposed the development of a dedicated Human Factors
Engineering standard while reducing the scope of IEC 60964 to a pure Control Room Design
standard. This reduction in scope is for a future edition of IEC 60964.
This document focuses on the application of a human factors engineering (HFE) programme to
the design of the human-machine interfaces throughout the lifetime of a nuclear facility,
including consideration of plant modifications.
This document is applicable to nuclear facilities such as: nuclear power plants (NPPs), research
reactors, uranium enrichment and nuclear fuel fabrication facilities, spent fuel storage and
reprocessing facilities.
It is intended that this document be used by operators of NPPs (utilities), and of other facilities
associated with the production of nuclear energy, systems designers, system evaluators and
by licensors.
It is further noted that, whilst existing standards such as those in the ISO 9241 series address
many aspects of the ergonomics of human-system interactions, those standards are judged to
be too detailed, extensive and in constant evolution to adequately guide the HFE programme
requirements within the scope of IEC SC 45A. However, reference is made to ISO 11064 for
certain aspects of the ergonomic design of control centres.
b) Situation of the current Standard in the structure of the IEC SC 45A standard series
The IEC human factors engineering (HFE) standard is on the same level as IEC 60964 and is
the second encompassing document within WG 8. The intention of WG 8 is to update the
standard environment step by step with the goal of linking all HFE related standards to this HFE
standard and linking all control room (CR) and HMI design-related standards to IEC 60964.

– 8 – IEC 63351:2024 © IEC 2024
Figure 1 shows the new structure after the update of all WG 8 standards.

Figure 1 – New WG 8 document structure
The documents shown on the left of the figure below the "IEC 60964" box constitute the existing
set of control room (CR) and HMI design-related standards and those on the right of the figure
below the "IEC 63351" box constitute the HFE related standards.
Due account has to be taken of the relationship between the standards in WG 8 when updating
IEC 60964 and the new HFE standard. New standards covering detailed information about HFE
may follow and be linked to this standard. Other standards currently pointing to IEC 60964 will
in future revisions need to point to both WG 8 high level documents. After the final update this
can be adapted based on the relevant content.
For more details on the structure of the IEC SC 45A standard series, see item d) of this
introduction.
c) Recommendations and limitations regarding the application of the Standard
This standard specifies the basic principles and requirements of an HFE programme for all
stages of the lifecycle of a nuclear facility.
It builds on the guidance provided by state-of-the-art HFE guides, such as IAEA SSG-51. It
covers the minimum requirements for the complete technical scope recognized by such guides
but points to other standards for specific detailed requirements.
To ensure that the standard will continue to be relevant in future years, the emphasis has been
placed on issues of principle, rather than on specific technologies or techniques.

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 IEC SC 45A standard series comprises a consistent set of documents organised in a
hierarchy of four levels. The top-level documents of the IEC SC 45A standard series are
IEC 61513 and IEC 63046, covering respectively general requirements for instrumentation and
control (I&C) systems and general requirements for electrical power systems of NPPs.
IEC 61513 and IEC 63046 adopt an overall system life-cycle framework and constitute, along
with the relevant second-level standards, the nuclear implementation of the basic safety series
IEC 61508.
IEC 61513 and IEC 63046 refer directly to other IEC SC 45A standards for general
requirements for specific topics, such as categorization of functions and classification of
systems, qualification, separation, defence against common cause failure, control room design,
electromagnetic compatibility, human factors engineering, cybersecurity, software and
hardware aspects for programmable digital systems, coordination of safety and security
requirements and management of ageing.
At a third level, IEC SC 45A standards not directly referenced by IEC 61513 or by IEC 63046
are standards related to specific requirements for specific equipment, technical methods, or
activities. Usually, these documents refer to second-level documents for general requirements
and 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.
The IEC SC 45A standards series consistently implements and details the safety and security
principles and basic aspects provided in the relevant IAEA safety standards and in the relevant
documents of the IAEA nuclear security series (NSS). In particular this includes the IAEA
requirements SSR-2/1 , establishing safety requirements related to the design of nuclear power
plants (NPPs), the IAEA safety guide SSG-30 dealing with the safety classification of structures,
systems and components in NPPs, the IAEA safety guide SSG-39 dealing with the design of
instrumentation and control systems for NPPs, the IAEA safety guide SSG-34 dealing with the
design of electrical power systems for NPPs, the IAEA safety guide SSG-51 dealing with human
factors engineering in the design of NPPs and the implementing guide NSS42-G for computer
security at nuclear facilities. The safety and security terminology and definitions used by the
SC 45A standards are consistent with those used by the IAEA.
IEC 61513 and IEC 63046 refer to ISO 9001 as well as to IAEA GSR part 2 and IAEA GS-G-3.1
and IAEA GS-G-3.5 for topics related to quality assurance (QA).
At level 2, regarding nuclear security, IEC 62645 is the entry document for the IEC/SC 45A
security standards. It builds upon the valid high-level principles and main concepts of the
generic security standards, in particular ISO/IEC 27001 and ISO/IEC 27002; it adapts them and
completes them to fit the nuclear context and coordinates with the IEC 62443 series. At level 2,
IEC 60964 is the entry document for the IEC/SC 45A control rooms standards, IEC 63351 is the
entry document for the human factors engineering standards and IEC 62342 is the entry
document for the ageing management standards.
NOTE IEC TR 63400 provides a more comprehensive description of the overall structure of the IEC SC 45A
standards series and of its relationship with other standards bodies and standards.

– 10 – IEC 63351:2024 © IEC 2024
NUCLEAR FACILITIES –
HUMAN FACTORS ENGINEERING –
APPLICATION TO THE DESIGN OF HUMAN-MACHINE INTERFACES

1 Scope
This document specifies the basic principles and requirements for the application of a human
factors engineering (HFE) programme to the design of the human-machine interfaces (HMI)
throughout the lifetime of a nuclear facility. The focus of this document is on control rooms and
control functions as discussed in the text.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 60964:2018, Nuclear power plants – Control rooms – Design
IEC 60965, Nuclear power plants – Control rooms – Supplementary control room for reactor
shutdown without access to the main control room
IEC 61227, Nuclear power plants – Control rooms – Operator controls
IEC 61771, Nuclear power plants – Main control room – Verification and validation of design
IEC 61772, Nuclear power plants – Main control room – Application of visual display units
(VDUs)
IEC 61839, Nuclear power plants – Design of control rooms – Functional analysis and
assignment
IEC 62241, Nuclear power plants – Main control room – Alarm functions and presentation
IEC 62954:2019, Nuclear power plants – Control rooms – Requirements for emergency
response facilities
IEC 63260:2020, Guide for incorporating human reliability analysis into probabilistic risk
assessments for nuclear power generating stations and other nuclear facilities
ISO 11064-1, Ergonomic design of control centres – Part 1: Principles for the design of control
centres
ISO 11064-2 (all parts), Ergonomic design of control centres – Part 2: Principles for the
arrangement of control suites
ISO 11064-3:1999 (all parts), Ergonomic design of control centres – Part 3: Control room layout
ISO 11064-4, Ergonomic design of control centres – Part 4: Layout and dimensions of
workstations
ISO 11064-5, Ergonomic design of control centres – Part 5: Displays and controls
ISO 11064-6, Ergonomic design of control centres – Part 6: Environmental requirements for
control centres
ISO 11064-7, Ergonomic design of control centres – Part 7: Principles for the evaluation of
control centres
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1 Control locations
3.1.1
control centre
combination of control rooms, control suites and local control stations which are functionally
related and all on the same site
Note 1 to entry: Depending on the context, the term "control centre" may be applied to a) one or more control rooms,
control suite or local control station, or b) some combination of these, or c) all of these.
Note 2 to entry: For NPPs, in addition to a main control room (as addressed in IEC 60964), the control centre
typically includes a supplementary control room (as addressed in IEC 60965) and a number of on-site emergency
response facilities (as addressed in IEC 62954).
[SOURCE: ISO 11064-3:1999, 3.1, modified – Notes to entry added]
3.1.2
control room
core functional entity, and its associated physical structure, where operators are stationed to
carry out plant operation, including centralized control, monitoring and administrative tasks
[SOURCE: ISO 11064-3:1999, 3.4, modified – "plant operation, including" inserted, and
"responsibilities" replaced by "tasks"]
3.1.3
control suite
group of functionally related rooms, co-located with the control room and including it, which
houses the supporting functions to the control room, such as related offices, equipment rooms,
rest areas and training rooms
[SOURCE: ISO 11064-3:1999, 3.6]

– 12 – IEC 63351:2024 © IEC 2024
3.1.4
human-machine interface
HMI
part of a system through which personnel interact with the system to perform their functions
and tasks
Note 1 to entry: The human-machine interface constitutes the interface between personnel and plant systems,
including procedures, communication systems, displays, alarms and controls.
[SOURCE: IAEA Nuclear Safety and Security Glossary, 2022 (Interim) Edition]
3.1.5
local control station
operator interface that is located near the equipment or system being monitored and/or
controlled
Note 1 to entry: Local control stations typically constitute the operator interface for a set of interrelated components
(with associated indications and controls), whereas local control points typically constitute that for stand-alone
components. Compared to a local control point, more detailed consideration is usually required prior to taking action
at a local control station, the impact being at the system level.
[SOURCE: ISO 11064-3:1999, 3.15, modified – Note to entry added]
3.1.6
local control point
LCP
point located outside the control room where local operators perform maintenance, surveillance
or control activities
Note 1 to entry: A control centre (see 3.1.1) includes local control stations (see 3.1.5), but not local control points.
[SOURCE: IEC 60964:2018, 3.20, modified – "maintenance, surveillance or" and Note to entry
added]
3.2 Function, task and performance
3.2.1
function
specific purpose or objective to be accomplished, that can be specified or described without
reference to the physical means of achieving it
Note 1 to entry: This equates to a medium level goal, broken down from a high-level safety or operational goal, to
allow an assignment to human or automation, not on the level of a more detailed specific task.
[SOURCE: IEC 61226:2020, 3.10 modified – Note to entry added]
3.2.2
functional analysis
examination of the functional goals of a system with respect to planned staffing, technology,
and other resources, to provide the basis for determining how the function may be assigned
and executed
Note 1 to entry: Functional analysis addresses "what is required to be done".
Note 2 to entry: See also the definition for TA (3.2.6).
3.2.3
performance requirements
qualitative and quantitative requirements specifying performance, which ensure the
achievement of functional goals

3.2.4
performance shaping factors
factors that influence human performance; they include factors such as environmental
conditions, human-machine interface design, procedures, training, and supervision
3.2.5
task
action performed by humans for the accomplishment of a functional goal
3.2.6
task analysis
TA
identification, description and evaluation of an operator’s task, in terms of its components, to
specify the detailed human activities involved, and their functional and temporal relationships
Note 1 to entry: TA addresses "how a required task is to be done".
Note 2 to entry: See also the definition for functional analysis (3.2.2).
3.3 Human factors aspects
3.3.1
end point vision
concept for the target control centre and/or HMI to be developed for guiding the planning, HFE
analyses, design and implementation over time to the desired final product
Note 1 to entry: The "end point vision" includes two conceptual aspects, HMI conceptual design and concept of
operations, which are elaborated through the HFE programme.
Note 2 to entry: The "end point vision" is determined at the outset of any project.
3.3.2
human engineering discrepancy
HED
departure from some benchmark of system design suitability for the roles and capabilities of
the human operator
Note 1 to entry: This may include a deviation from a standard or convention of human engineering practice, an
operator preference or need, or an instrument/equipment characteristic that is implicitly or explicitly required for an
operator’s task but is not provided to the operator
Note 2 to entry: In some countries, the term "human factors issue" is used.
3.3.3
human error
discrepancy between the human action taken or omitted, and that intended or required
EXAMPLE Performing an incorrect action; omitting a required action; miscalculation; misreading a value.
[SOURCE: IEC 60050-192:2015, 192-03-14]
3.3.4
human factors engineering
HFE
application of knowledge and methods to take HF into account in the design of the plant, its
systems, and equipment to ensure optimal performance and safety
3.3.5
human interaction
interrelation between the user and the human-machine interface, specifically, display of plant
status by the human-machine interface and corresponding user action

– 14 – IEC 63351:2024 © IEC 2024
3.3.6
important human task
IHT
human task that can have an adverse or positive effect on safety, as determined by safety
analysis
[SOURCE: IAEA Nuclear Safety and Security Glossary, 2022 (Interim) Edition]
3.3.7
situation awareness
dynamic process of perception and comprehension of the plant’s actual condition in order to
support the ability of individuals and teams to predict the future conditions of systems
Note 1 to entry: The degree of situation awareness corresponds to the difference between the understanding of
plant conditions and the actual conditions at any given time.
[SOURCE: IAEA Nuclear Safety and Security Glossary, 2022 (Interim) Edition]
3.3.8
staffing, organisation and qualification analysis
definition and analysis
...