IEC 60987:2021 pdf download – Nuclear power plants – Instrumentation and control important to safety – Hardware requirements.
3.2 common cause failure, CCF failure of two or more structures, systems or components due to a single specific event or cause Note 1 to entry: Common causes can be internal or external to an I&C system. [SOURCE: IAEA Safety Glossary: 201 8, modified – Note 1 to entry has been added.] 3.3 component one of the parts that make up a system Note 1 to entry: A component can be hardware, software or HPD and can be subdivided into other components. Note 2 to entry: See also “I&C system”, “equipment”. Note 3 to entry: The terms “equipment”, “component”, and “module” are often used interchangeably. The relationship of these terms is not yet standardised. Note 4 to entry: This IEC SC 45A definition is in principle compatible with the sub-definition of “Component” given in the frame of the 201 8 edition of the IAEA Safety Glossary definition of “Structures Systems and Components (SSC)”. Nevertheless, as only examples of hardware components are given, this can mislead the reader and IEC SC 45A prefer to use a definition which explicitly covers software components. [SOURCE: IEC 61 51 3:201 1 , 3.1 0, modified – last sentence of definition turned into Note 1 to entry and edition 2007 of IAEA Safety Glossary has been updated to edition 201 8.]
3.4 computer-based item item that relies on software instructions running on microprocessors or microcontrollers Note 1 to entry: In this term and its definition, the term item can be replaced by the terms: system, or equipment, or device. Note 2 to entry: A computer-based item is a kind of programmable digital item. Note 3 to entry: This term is equivalent to software-based item. Note 4 to entry: The definitions for the following terms: E/E/PE item, Electrical item, I&C systems, Programmable digital item, Computer-based item, Hardwired item, Programmable Logic Device, HPDs have to be considered in conjunction and are totally consistent and coherent. They are totally consistent and coherent with the general requirements established by IEC 61 51 3 and IEC 63046 for instrumentation, control and electrical systems for nuclear power plants. [SOURCE: IEC 621 38:201 8, 3.8, modified – Note 4 to entry has been added.] 3.5 electrical / electronic / programmable electronic item E/E/PE item item based on electrical (E) and/or electronic (E) and/or programmable electronic (PE) technology Note 1 to entry: In this term and its definition, the word “item” can be replaced by the words: system, or equipment, or device. Note 2 to entry: The definitions for the following terms: E/E/PE item, Electrical item, I&C systems, Programmable digital item, Computer-based item, Hardwired item, Programmable Logic Device, HDL Programmed Device (HDL Hardware Description Language), have to be considered in conjunction and are totally consistent and coherent. They are totally consistent and coherent with the general requirements established by IEC 61 51 3 and IEC 63046 for instrumentation, control and electrical systems for nuclear power plants. [SOURCE: IEC 621 38:201 8, 3.1 5, modified – Note 2 to entry has been added.]
3.6 electrical power system EPS system performing electrical power generation, transmission and distribution; performing supply functions to operate plant equipment (pumps, valves, heaters, etc.) Note 1 to entry: An electrical system can integrate E/E/PE items to perform its internal electrical control and protection. [SOURCE: IEC 63046:2020, 3.1 2] 3.7 equipment one or more parts of a system Note 1 to entry: An item of equipment is a single definable (and usually removable) element or part of a system. Note 2 to entry: See also “component”, “I&C system”. Note 3 to entry: Equipment may include software. Note 4 to entry: The terms “equipment”, “component”, and “module” are often used interchangeably. The relationship of these terms is not yet standardised. [SOURCE: IEC 61 51 3:201 1 , 3.1 6, modified – last sentence of definition turned into Note 1 to entry and Note 4 to entry of IEC 61 51 3 has been removed.] 3.8 firmware software which is closely coupled to the hardware characteristics on which it is installed Note 1 to entry: The presence of firmware is generally “transparent” to the user of the hardware component and, as such, can be considered to be effectively an integral part of the hardware design (a good example of such software being processor microcode). Note 2 to entry: Generally, firmware can only be modified by a user by replacing the hardware components (for example, processor chip, card, EPROM) which contain this software with components which contain modified software (firmware). Where this is the case, configuration control of the hardware components by the users of the equipment effectively provides configuration control of the firmware. Firmware, as considered by this document, is effectively software that is built into the hardware