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NB/T 20063-2012 PDF in English

NB/T 20063-2012 (NB/T20063-2012, NBT 20063-2012, NBT20063-2012)
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NB/T 20063-2012: PDF in English (NBT 20063-2012)

NB/T 20063-2012
ICS 27.120.01
F 80
Filing number: 35988-2012
Glossary of terms of instrumentation and control for
nuclear power plants
Issued by: National Energy Administration
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Basic concepts ... 4 
3 Instrumentation control systems and device ... 18 
4 Computer applications ... 36 
5 Man-machine interface ... 41 
6 Qualification ... 46 
7 Test and maintenance ... 57 
References ... 67 
English index ... 71 
Glossary of terms of instrumentation and control for
nuclear power plants
1 Scope
This standard specifies common terms and definitions related to
instrumentation and control (I&C) for nuclear power plants and their power
This standard applies to applications for nuclear power plant; other nuclear
facilities can be used with reference to it.
2 Basic concepts
Operational states
A collective name for two types of states, normal operation and anticipated
operational occurrences.
[HAF 102 (2004)]
Normal operation
The operation of nuclear power plants within specified operating limits and
[HAF 102 (2004)]
Design basis
Information that determines the value, or range of parameters, of a structure,
system, component, or device that performs a specific function and is a
design boundary. This information can be either limits (derived from
generally accepted practices to achieve a functional goal), or some
requirements [derived from operational analysis of the assumed events
wherein the structures, systems, components shall meet their functional
Accident conditions with severity exceeding design basis accidents.
Note: Certain beyond design basis accidents do not cause significant
degradation of core performance.
[IAEA Safety Glossary: 2007]
Accident conditions
Working conditions which are more severe than anticipated operational
events, including design basis accidents and severe accidents.
[HAF 102 (2004)]
Severe accident
Accident conditions with a severity that exceeds the design basis accident
and causes a significant deterioration of the reactor core.
[HAF 102 (2004)]
Accident management
A series of actions taken during the development of beyond design basis
a) In order to prevent the accident that the core is not severely damaged
from escalating to a severe accident;
b) In order to mitigate the consequences of severe accidents;
c) In order to achieve a long-term stable state of safety.
Note: Rewrite the definition of HAF 102 (2004).
Station blackout
In the nuclear power plant, all the AC power supply to the buses of important
and non-important power distribution devices is lost, that is, the off-site
power is lost, the turbine is tripped and the emergency AC power supply in
the station is faulty, but the AC power or alternative AC power as fed from
[GB/T 4960.6-2008, definition 4.3.8]
Trip setpoint
A predetermined set value for triggering an action.
Note: Rewrite IEC 61888:2002, definition 3.22.
Safety class
A safety class for electrical device and systems in nuclear power plants,
which are necessary to complete emergency shutdown of the reactor,
containment isolation, core cooling, exhaust heat from the containment and
reactor, or to prevent large amounts of radioactive material from being
discharged to the environment .
Note 1: Safety class (Class 1E) is a functional term. Devices and systems
can only be classified as safety class if they complete the functions listed in
this part; systems or devices shall not be classified as safety class based on
other functions.
Note 2: Rewrite GB/T 13284.1-2008, definition 3.7.
Safety action
A single action taken by a safety drive system.
[GB/T 4960.6-2008, definition 4.4.7]
Safety measures
Any action that may be taken to achieve the basic requirements of the safety
requirements, any conditions that may be imposed, or any procedures that
may be followed.
[IAEA Safety Glossary: 2007]
Protective task
hardware aging and degradation) or system faults (such as software faults)
caused by design errors.
Note 2: A fault (especially a design fault) in the system may not be
discovered until certain conditions occur (that is, the result does not meet
the expected function, that is, a failure occurs).
Note 3: See "Software failure".
[NB/T 20026-2010, definition 3.22]
A design principle that causes the system to tend to increase safety action
when any component in the system fails.
[GB/T 4960.6-2008, definition 4.1.16]
Detectable failures
Failures that can be identified through periodic tests, or failures discovered
through alarms or abnormal displays. Component failures detected at the
channel, sequence, or system level are all detectable failures.
Note: The failures that can be discriminated but not detectable are failures
that are judged through analysis. Such failures can neither be discovered
through periodic tests, nor can they be discovered through alarms or
abnormal displays.
[GB/T 13284.1-2008, definition 3.11]
Failure mode
The manner or state in which a structure, system, or component has failed.
[IAEA Safety Glossary: 2007]
Common mode failure
Failure of two or more structures, systems, or components caused by a
single event or cause in the same manner or mode.
safety, they can be classified as "not categorized".
Note 1: GB/T 15474 defines the categories of the I&C functions and related
systems and device (FSE). Each category corresponds to a set of
requirements. These requirements apply to I&C functions (including their
specifications, design, implementation, verification, confirmation), it is also
applicable to all items necessary for the realization of functions (involving
characteristics and related quality assessment), regardless of how these
items are distributed and interconnected in the I&C system. For the sake of
clarity, this standard defines the categories of I&C functions and the levels
of I&C systems, meanwhile specifies the relationship between the functional
categories and the minimum levels required by the relevant systems and
Note 2: Rewrite NB/T 20026-2010, definition 3.4.
A category of an I&C function
Functions that play a major role in achieving or maintaining nuclear power
plant’s safety to prevent DBE from causing unacceptable consequences.
Note: A category functions also include those whose failures can directly
cause accident conditions if it cannot be mitigated by other A category
B category of an I&C function
Playing the function of supplementing the A category function to achieve or
maintain the safety of nuclear power plant, especially functions required to
operate after reaching a controlled state, in order to prevent DBE from
causing unacceptable consequences or mitigating the effects of DBE.
Note: B category also includes those functions whose failure may cause or
worsen DBE. Because A category functions can ultimately prevent or
mitigate the consequences of DBE, the safety requirements for B category
functions do not have to reach the height of A category functions. If required,
allow B category functions to be more functional than A category functions
in the detection of a required action or its subsequent actions.
C category of an I&C function
Functions that assist or indirectly play a role in achieving or maintaining the
Based on operating experience and the availability of new processes and
new materials, the modernization of design or functionality improvement of
the device. This includes choosing materials that are more resistant to aging,
reconfiguration to improve reliability, even rearranging device and adding
new features.
[IEC 62342:2007, definition 3.20]
3 Instrumentation control systems and device
3.1 Instrument control system
Electrical system
Integration of electrical device that performs a certain function.
Instrumentation and control system (l&C system)
A system based on electrical, electronic, and/or programmable electronic
technology, that performs I&C functions as well as service and supervision
functions related to the operation of the system itself.
Note 1: According to the typical functional characteristics of the I&C systems,
the IAEA distinguishes between automatic control systems, HMI systems,
interlock systems, protective systems.
Note 2: Rewrite NB/T 20026-2010, definition 3.35.
I&C systems important for safety
The instrumentation control system whose failure or malfunction may cause
the plant personnel or the public to experience excessive radiological
exposure to the instrumentation and control systems, as well as those
instrumentation control system to prevent unforeseen consequences of
anticipated operational occurrences, including safety systems and safety-
related instrumentation control systems.
Reactor trip system
Part of the safety system, a combination of device that quickly reduces the
reactor's neutron fluence rate to stop the reactor through irreversible actions.
[GB/T 4960.6-2008, definition 4.4.37]
Automatic power cutback (runback) system
This system automatically controls the reduction of the reactivity at the
specified speed of the control rod; reduces the reactor power to a
predetermined level programmatically.
[GB/T 4960.6-2008, definition 4.4.34]
Train; division
The name of a given system or device group, that is physically, electrically,
functionally independent of other redundant equipment groups.
[GB/T 4960.6-2008, definition 4.1.29]
Channel; train
The configuration where several interconnected components in the system
emit a single output signal, where the single output signal is combined with
signals from other channels (such as monitoring channels or safety actuation
channels), the channel is terminated.
[GB/T 4960.6-2008, definition 4.1.30]
A qualitative representation of the range or scope of functions a system or
device can perform.
Note: A system that can perform many complex functions is "highly
functional"; a system that can only perform a few simple functions is "low-
A device that senses what is measured and converts it into an output of the
same or another nature according to a certain rule.
[GB/T 13983-1992, definition 5.3]
A sensor that outputs a standardized signal. For example: pressure
transmitter, concentration transmitter, frequency transmitter, etc.
[GB/T 13983-1992, definition 5.4]
Functional unit
A component or combination of components that performs one or more basic
Note: For example, in the "calibrator", "forming unit", "pulse amplitude
screening unit", "calibration unit" are all functional units.
[GB/T 4960.6-2008, definition 3.1.6]
Execute features
It is composed of electrical device and mechanical device and their
connecting parts. After receiving the signal from the monitoring instruction
device, it performs a function directly or indirectly related to the safety
function. The scope of the execute feature starts from the output end of the
monitoring instruction device, until reaching to (and including) the coupling
between the execute feature and the process.
Note 1: In some cases, protective actions can be performed for the actuators
(such as check valves, self-relief valves) that respond directly to process
Note 2: The execute feature usually includes valve actuator, prime mover,
actuated equipment.
[GB/T 13284.1-2008, definition 3.13]
Preferred power supply (PPS)
Under the accident and post-accident conditions, the power source that
supplies power to the safety-level power system from the transmission
system is given priority.
[GB/T 12788 -2008, definition 3.19]
Standby power supply
The power supply used to supply power when the priority power supply is
[GB/T 12788-2008, definition 3.30]
Uninterruptible power supply (UPS)
A power supply consisting of a rectifier device, an inverter device, a
secondary cell pack, a power switch to continuously supply power to loads
such as instrumentation and control systems important to safety.
Note: Rewrite GB/T 4960.6-2008, 3.3.21.
Alternative ac source (AAC)
An AC power source installed in or near a nuclear power plant and meets
the following requirements:
a) It can be connected (but usually not connected) to an emergency AC
power system off-site or on-site;
b) The probability of common mode failure with the priority power supply or
the emergency AC power supply in the station is the least;
c) Power can be supplied in time after the station blackout;
d) Sufficient capacity and reliability to operate all systems required in case
of station blackout, and to ensure safe shutdown and maintain the power
consumption within the safe shutdown period (beyond design basis
Impulse line (sensing line)
Pipes that connect the process to the sensors. Impulse lines (sensing lines)
are commonly used to connect pressure, level, and flow transmitters to the
process, their lengths range from a few meters to hundreds of meters. The
sensing line may also contain isolation and root valves as well as other
related device along the line.
Note: Rewrite ISA 67.01.01:2002, definition 3.9.
The degree to which an item's overall characteristics meet specified or
expected requirements.
[NB/T 20026-2010, definition 3.46]
All written or graphical records of descriptions, definitions, instructions,
reports or certifications related to activities, requirements, processes or
[GB/T 12788-2008, definition 3.11]
Quality assurance
Planned and systematic activities required to provide adequate assurance
that products or services meet specified quality requirements.
[NB/T 20026-2010, definition 3.47]
Quality plan
Documents that specify specific quality activities and the resources and
procedures for those activities for a particular product, project or contract.
[NB/T 20026-2010, definition 3.48]
[GB/T 4960.6-2008, definition 2.2.5]
Fission ionization chamber
The ionization chamber which uses fissionable material as a sensitive layer
to detect neutron.
Note 1: Ionization is caused by fission fragments generated by a nuclear
reaction between neutrons and fissile material.
Note 2: Depending on the fissile material used, detection of thermal neutrons,
fast neutrons, neutrons of various energies are possible.
Note 3: See definitions of fission [IEV 393-11-26] and fissile [IEV 393-11-28].
[GB/T 4960.6-2008, definition 2.2.11]
Self-powered neutron detector (SPND)
A detector that does not require an external power source and converts
incident radiation into electrical signals through the action of its emitter
(sensitive material) and neutrons.
[GB/T 8995-2008, definition 3.6]
SeIf-powered detector
Neutron or gamma-ray detectors that generate weak electrical signals
through neutron and gamma-ray activation without the need for an external
power source.
Note: GB/T 2900.82-2008, revise definition 394-24-04.
(Liquid or gaseous) effluent monitor
Device for continuously monitoring the radioactivity of a gaseous exhaust
stream or a liquid exhaust stream discharged to the environment in a gas
exhaust system.
Note: Rewrite GB/T 2900.82-2008, definition 394-32-22.
Useful life of a neutron detection
Under the radiation and environmental conditions within the specified range,
the working life of the detector when its characteristic index exceeds the
specified deviation. It can be expressed by the fluence of incident particles,
the generated pulse count, and the like.
[GB/T 8995-2008, definition 3.14]
4 Computer applications
Computer-based system
The I&C system whose functions are mainly dependent on or completely
implemented by microprocessors, programmable electronics or computers.
[NB/T 20026-2010, definition 3.10]
Programs (ordered instruction sets), data, rules, and all related documents
related to the operation of computer-based I&C systems.
[NB/T 20054-2011, definition 3.30]
System software
Software part of an I&C system designed for a specific computer or device
family, to facilitate the development, operation, modification of computer
systems and related programs.
Software designed for a particular computer system or computer system
family, to facilitate the operation and maintenance of the computer system
and its related programs, such as operating systems, compilers, utilities.
System software usually consists of operating system software and
supporting software.
[NB/T 20054-2011, definition 3.36]
Automated code generation
The function of an automated tool that translates an application-oriented
language into code that can be compiled or executed.
[NB/T 20054-2011, definition 3. 5]
Software safety life cycle
The necessary activity involved in the development or operation process
from the time when the I&C system software important for safety proposes
the software requirements specification in the concept design stage to the
point when the software is no longer used and ends.
[NB/T 20054-2011, definition 3.33]
1) The process of converting a design into a hardware device, a software
device, or both;
2) Results for defining the 1) process.
[GB/T 13629-2008, definition 3.32]
Functional validation
Verification of the correctness of the application function specifications
according to the top-level power plant function and performance
requirements. It complements system validation (verification of system
compliance with functional specifications).
[NB/T 20026-2010, definition 3.24]
The suspension of the process (such as the execution of a computer
program) as caused by an event external to the process.
When the meter's reading exceeds a setting value or exceeds the setting
range, an audible or visual signal is triggered on the alarm panel and other
displays, to provide field personnel with information about the device or
[GB/T 4960.6-2008, definition 4.4.23]
Alarm system
A system used to alert the operator in case of an abnormal situation, such
as a system or process deviation, may require corrective action.
[GB/T 4960.6-2008, definition 4.4.25]
Warning system (of reactor)
Part of an alarm system that provides visual and audible signals for
conditions that are abnormal, but not immediately severe, even temporarily.
[GB/T 4960.6-2008, definition 4.4.26]
Alarm display processing
Alarm signal processing functions or mechanisms for controlling or
improving alarm display, for example, combined alarm, alarm suppression.
Note: The object of alarm display processing is the alarm as identified by the
alarm signal processing logic.
[NB/T 20027-2010, definition 3.6]
Alarm prioritization
Alarm signal processing function or mechanism for alarms classified by
Note: Priority can be defined in advance or determined dynamically based
on plant operating conditions.
performance, and human error plays an important role in the risk that the
system may occur.
[IEEE 1023:2004, definition 3.5]
Human error
The manual operation deviates from the expected result to meet the specific
requirements of correctness, completeness, appropriateness or timeliness.
[IEEE 1023:2004, definition 3.3]
6 Qualification
6.1 Device qualification
Baseline parameter
The initially determined technical data, which is used as a benchmark for
evaluating the acceptable performance of the qualified sample.
[IEEE 572:2006, definition 3.1]
Service condition
A collective term for the environment, load, power source, and signal
conditions during the normal operation, abnormal operation, or design basis
event of a nuclear power plant.
[IEEE 323:2003, definition 3.17]
Operating experience
Accumulation of verifiable operating data under operating conditions
comparable to the qualification conditions of the particular device being
Note: Rewrite GB/T 15473-1995, definition 3.5.
[IEEE 323:2003, definition 3.16]
Residual life
The duration for which a structure, device or component performs its safety
function under specified operating conditions and is expected to be
[IEEE 1205:2000, definition 3.5]
Service life
The time from the initial operation of a structure, system, or component to its
final retirement.
[IEEE 1205:2000, definition 3.6]
Equipment qualification
Evidence obtained through analysis, type testing, or operating experience
proves that the device can function according to the specified accuracy and
performance requirements under the specified operating conditions and
environmental conditions.
Note: Rewrite GB/T 12727-2002, definition 3.8.
Qualification margin
The difference between the test conditions at the time of the qualification and
the actual operating conditions.
Note: Rewrite IEEE 323:2003, definition 3.13.
Approval of qualification
The process of approving a device as qualified.
Note: Conditions required for approval to qualify device:
- Condition 1, the device shall be suitable for the intended use;
[GB/T 13625-1992, definition 3.13]
Correlation coefficient
A measure of the degree of correlation between two time-history curves. It
is a function of time and provides a statistical estimate of the degree of
correlation between two motions in the time domain. The value ranges from
0 (irrelevant motion) to 1 (fully correlated motion).
[NB/T 20040-2011, definition 3.23]
Coherence coefficient
A measure of the degree of correlation between two time-history curves. It
is a function of frequency and provides a statistical estimate of the degree of
correlation between two motions in the frequency domain. The value ranges
from 0 (irrelevant motion) to 1 (fully correlated motion).
[NB/T 20040-2011, definition 3.24]
Floor acceleration
Acceleration caused by a specific seismic motion on the floor of a specific
[GB/T 13625-1992, definition 3.16]
Ground acceleration
The ground acceleration caused by a given seismic motion. The maximum
ground acceleration is equal to the zero-period acceleration (ZPA) of the
ground response spectrum.
[IEEE 344:2004, definition 3.11]
Cutoff frequency
The frequency at which the zero-period acceleration asymptote begins in the
response spectrum (i.e., the starting frequency where the spectral
[NB/T 20040 -2011, definition 3.21]
Flexible equipment
Device, structures and components with a minimum resonance frequency
below the cut-off frequency of the response spectrum.
[NB/T 20040-2011, definition 3.22]
Damping is a general term that describes the energy loss caused by various
mechanisms in a system. Actually, damping depends on many parameters,
such as structural system, vibration mode, deformation, applied force, speed,
material, joint slip and so on.
[GB/T 2423.48-2008, definition 3.2]
Critical damping
The minimum viscous damping that allows a shifted system to return to its
original position without oscillation within the shortest time allowed.
[GB/T 2423.48-2008, definition 3.3]
Damping ratio
In viscous damping systems, the ratio of actual damping to critical damping.
[GB/T 2423.48-2008, definition 3.4]
6.2 Aging management
(Natural) aging
Under operating conditions within the design range, the change of the
physical, chemical, or electrical characteristics of a component or device
over time. Such changes may cause its important functional characteristics
to deteriorate.
[GB/T 13625-1992, definition 3.19]
In-situ test
Channel performance test of the instrument channel’s sensor or component
without leaving the system's normal installation position.
[ISA 67.06.01:2002, definition 3.12]
Periodic testing
Tests performed at planned intervals to detect faults and check operability.
[GB/T 5204-2008, definition 3.4]
Surveillance testing
All activities to demonstrate that the functional capabilities of I&C system
and device important to safety are maintained and meet design basis
[IEC 60671:2007, definition 3.9]
Overlap testing
In order to check the function of the entire channel, train or load group, tests
performed on different parts or subsystems of the channel, train or load
group. Testing of different parts or subsystems shall cover adjacent
[GB/T 5204-2008, definition 3.5]
Functional test
A test to determine that a component or system performs its intended
[GB/T 5204-2008, definition 3.7]
Preoperational test
After the system device is installed and integrated, the test which is used to
verify that the system and its components can function as designed before
the fuel is loaded.
Factory acceptance test (FAT)
Activities to prove that the supplier’s device and its auxiliary device meet the
technical specifications.
[IEC 62381:2006, definition 2.3]
Site acceptance test (SAT)
Activities to prove that the installation of various device of the supplier
conforms to the corresponding specifications and installation details. Site
integration tests may sometimes be included.
[IEC 62381:2006, definition 2.4]
Site integration test (SIT)
The test to prove that the components have been combined into a complete
system and that all components have been integrated as required.
Note 1: Sometimes included in the site acceptance test.
Note 2: Rewrite IEC 62381:2006, definition 2.5.
Acceptance criteria
A specification of a functional or status indicator used to assess the ability of
a structure, system, or component to perform its designed function.
[IAEA Safety Glossary: 2007]
Test plan
[ISA 67.06.01:2002, definition 3.18]
Response time
The time elapsed from the step change of the measured variable to the time
when the output signal first reaches a given percentage (usually 90%) of its
final value.
Note: Rewrite ISA 67.06.01:2002, definition 3.21.
Instrument channel response time
The elapsed time for the process variable in the instrument channel to
change from the start to the trigger.
Note: Rewrite ISA 67.06.01:2002, definition 3.14.
Time constant
The time elapsed from the input of a step change signal to the time when
the output signal first reaches a given percentage of its final value (usually
Note 1: The time constant is only applicable to first-order systems; the
response time is used for multi-order systems.
Note 2: ISA 67.06.01:2002, revise definition 3.27.
The degree of consistency between the displayed value of the instrument
and the measured (conventional) true value.
[GB/T 13983-1992, definition 4.35]
Accuracy of measurement
The degree of consistency between the measurement result and its agreed
true value.
Electromagnetic compatibility (EMC)
The ability of a device or system to function properly in its electromagnetic
environment and not to constitute unsustainable electromagnetic
disturbance to anything in that environment.
[GB/T 4365-2003, definition 161-01-07]
Electromagnetic disturbance
Any electromagnetic phenomenon that may cause the performance of the
device, equipment or system to decrease or adversely affect living or abiotic
Note: Electromagnetic ......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.