Instrumentation, Control and Electrical Power Systems of Nuclear Facilities

IEC 61226:2020 establishes, for nuclear power plants , a method of assignment of the functions specified for the plant into categories according to their importance to safety. Subsequent classification of the I&C and electrical power systems performing or supporting these functions, based on the assigned category, then determines relevant design criteria.
The design criteria, when applied, ensure the achievement of each function in accordance to its importance to safety. In this document, the criteria are those of functionality, reliability, performance, environmental qualification (e.g. seismic) and quality assurance (QA).
This edition includes the following significant technical changes with respect to the previous edition:
- to align on IAEA requirements, recommendations and terminology, particularly to take into account the replacement of NS-R-1 by SSR 2/1 and publication of SSG 30;
- to extend the scope to electrical power systems;
- to move the detailed requirements applying to functions and I&C systems to a normative annex, which will be removed after updating IEC 61513.

IEC 61225:2019 specifies the performance and the functional characteristics of the low voltage static uninterruptible power supply (SUPS) systems in a nuclear power plant and, for applicable parts, in general for nuclear facilities. An uninterruptible power supply is an electrical equipment which draws electrical energy from a source, stores it and maintains supply in a specified form by means inside the equipment to output terminals. A static uninterruptible power supply (SUPS) has no rotating parts to perform its functions.
This third edition cancels and replaces the second edition published in 2005. This edition includes the following significant technical changes with respect to the previous edition:
a) the principal objective of this edition is to address the requirements on the static uninterruptible power supplies in nuclear power plants;
b) in addition to Instrumentation and Control (I&C) power supplies include all static uninterruptible power supplies;
c) emphasize that the static uninterruptible power supplies shall protect the connected equipment (loads) from transients on the on-site AC distribution system (the immunity concept);
d) in accordance with the defence-in-depth concept, this standard applies to static uninterruptible power supplies for all equipment, not only for equipment important to safety, with a graded approach to verification and validation;
e) addition of the requirement that, when batteries are connected in parallel under abnormal operating conditions, they shall be properly protected with isolation devices to avoid any failure that may impair more than one division of the uninterruptible power supply.

Defines the intended criteria for the choice, conception and use of equipment for the measurement of the response time of resistance temperature detectors (RTD) which are used in the safety and control systems of nuclear reactors. Describes the techniques which can be used for the in situ measurement of RTD response time.

IEC 61031:2020 applies to the design, location and application of installed equipment for monitoring local gamma radiation dose rates within nuclear facilities during normal operation and anticipated operational occurrences. High range area gamma radiation dose rate monitoring equipment for accident conditions currently addressed by IEC 60951-1 and IEC 60951-3 is not within the scope of this document. This document does not apply to the measurement of neutron dose rate. Additional equipment for neutron monitoring may be required, depending on the plant design, if the neutron dose rate makes a substantial contribution to the total dose equivalent to personnel.
This document provides guidelines for the design principles, the location, the application, the calibration, the operation, and the testing of installed equipment for continuously monitoring local gamma radiation dose rates in nuclear facilities under normal operation conditions and anticipated operational occurrences. These instruments are normally referred to as area radiation monitors. Portable instruments are also used for this purpose but are not covered by this document.

IEC 60988:2009 is applicable to on-site systems used for continuous monitoring of structure-borne sound measured at the reactor coolant pressure boundary of light water reactors for the purpose of detecting loose parts. The main technical changes with regard to the previous edition are as follows:
- to bring the contents up to date with technology change in some areas and to reconsider and improve the recommendations;
- to include considerations and recommendations on digitalization for loose parts monitoring systems to cover requirements for such systems;
- to include improved and updated recommendations on storage, information display, alarm level monitor and logic elements;
- to give recommendations on functional and performance measures proven in use for operation of the monitoring system including updated details on the necessary actions after detection of a loose part;
- to improve the consistency and clarity and the layout of the contents and to correct any errors found in the previous version.

IEC 60987:2021 provides requirements and recommendations for the hardware aspects of I&C systems whatever the technology and applies for all safety classes in a graded manner (as defined by IEC 61513). The requirements defined within this document guide, in particular, the selection of pre-existing components, hardware aspects of system detailed design and implementation and equipment manufacturing.
This third edition cancels and replaces the second edition published in 2007. This edition includes the following significant technical changes with respect to the previous edition:
a) Title modified;
b) Take account of the fact that hardware requirements apply to all I&C technologies, including conventional hardwired equipment, programmable digital equipment or by using a combination of both types of equipment;
c) Align the standard with the new revisions of IAEA documents SSR-2/1, which include as far as possible an adaptation of the definitions;
d) Replace, as far as possible, the requirements associated with standards published since the edition 2.1, especially IEC 61513, IEC 60880, IEC 62138, IEC 62566 and IEC 62566‑2;
e) Review the existing requirements and update the terminology and definitions;
f) Extend the scope of the standard to all hardware (computerized and non-computerized) and to all safety classes 1, 2 and 3;
g) Complete, update the IEC and IAEA references and vocabulary;
h) Check possible impact of other IAEA requirements and recommendations considering extension of the scope of SC 45A;
i) Highlight the use of IEC 62566 and IEC 62566-2 for HPD development;
j) Introduce specific activities for pre-existing items (selection, acceptability and/or mitigation);
k) Introduce clearer requirements for electronic module-level design, manufacturing and control;
l) Complete reliability assessment methods;
m) Introduce requirements when using automated tests or control activities;
n) Complete description of manufacturing control activities (control process, assessment of manufactured equipment, preservation of products);
o) Define and ensure the inclusion of a graded approach for dealing with the 3 different classes of equipment and related requirements.

IEC 60965:2016 establishes requirements for the Supplementary Control Room provided to enable the operating staff of nuclear power plants to shut down the reactor, where previously operating, and maintain the plant in a safe shut-down state in the event that control of the safety functions can no longer be exercised from the Main Control Room, due to unavailability of the Main Control Room or its facilities. The design has to ensure that the Supplementary Control Room is protected against the hazards, including any localised extreme hazards, leading to the unavailability of the Main Control Room. This new edition includes the following significant technical changes with respect to the previous edition:
- requirements associated with regular testing of the supplementary control room (SCR);
- requirements to assess the time available during which the reactor will be safe but unattended, in order to move from the main control room (MCR) to the SCR and for the SCR to become operational;
- taking into account new requirements laid down by the IAEA.

IEC 60964:2018 RLV contains both the official IEC International Standard and its Redline version. The Redline version is available in English only and provides you with a quick and easy way to compare all the changes between the official IEC Standard and its previous edition.
IEC 60964:2018 establishes requirements for the human-machine interface in the main control rooms of nuclear power plants. The document also establishes requirements for the selection of functions, design consideration and organization of the human-machine interface and procedures which are used systematically to verify and validate the functional design. These requirements reflect the application of human factors engineering principles as they apply to the human-machine interface during plant operational states and accident conditions (including design basis and design extension conditions), as defined in IAEA SSR-2/1 and IAEA NP-T-3.16. This third edition cancels and replaces the second edition published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) to review the usage of the term “task” ensuring consistency between IEC 60964 and IEC 61839;
b) to clarify the role, functional capability, robustness and integrity of supporting services for the MCR to promote its continued use at the time of a severe accident or extreme external hazard;
c) to review the relevance of the standard to the IAEA safety guides and IEC SC 45A standards that have been published since IEC 60964:2009 was developed;
d) to clarify the role and meaning of “task analysis”,
e) to further delineate the relationships with derivative standards (i.e. IEC 61227, IEC 61771, IEC 61772, IEC 61839, IEC 62241 and others of relevance to the control room design);
f) to consider its alignment with the Human Factors Engineering principles, specifically with the ones of IAEA safety guide on Human Factors (DS-492) to be issued.

Considers the functional design criteria for a Safety Parameter Display System (SPDS) giving concise information to aid operating personnel, particularly in abnormal conditions. An SPDS is made up of instruments, displays, computer hardware and software either constituting a stand-alone system or integrated into the control room information system. Applies only to control rooms designed in accordance with the IEC control room design standard.

IEC 60951-4:2009 provides general guidance on the design principles and performance criteria for equipment for continuous in-line or on-line monitoring of radioactivity in process stream in nuclear power plants for accident and post-accident conditions. General requirements for technical characteristics, test procedures, radiation characteristics, electrical, mechanical, and environmental characteristics are given in IEC 60951-1. These requirements are applicable in this part unless otherwise stated. The main technical changes with regard to the previous edition are as follows:
- clarify the definitions;
- up-date the references to new standards published since the first edition;
- update the units of radiation.

This publication is to be read in conjunction with IEC 60951-1:2009.