NB/T 20318-2014 English PDF (NB/T20318-2014)

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NB/T 20318-2014: Pressure transmitter important to safety in nuclear power plants
NB/T 20318-2014
ENERGY INDUSTRY STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
ICS 27.120.20
F 83
Filing number: 47837-2015
Pressure transmitter important to safety in nuclear
power plants
ISSUED ON: OCTOBER 15, 2014
IMPLEMENTED ON: MARCH 01, 2015
Issued by: National Energy Administration
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Transmitter type and electrical parameters ... 7 
5 Transmitter’s function and operating conditions ... 8 
6 Technical requirements ... 9 
7 Inspection and test ... 17 
8 Marking, packaging, transportation and storage ... 24 
9 Documentation ... 24 
Appendix A (Informative) Environmental conditions of pressure transmitters in
the containment of nuclear power plants ... 26 
Pressure transmitter important to safety in nuclear
power plants
1 Scope
This standard specifies the basic requirements for the design, manufacture,
qualification, testing and documentation of pressure transmitters important to
the safety of nuclear power plants.
This standard applies to pressure transmitters important to the safety for
continuous monitoring of process variables (pressure, flow, differential pressure,
level) in nuclear power plants.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
GB 4208-2008 Degrees of protection provided by enclosure (IP code)
GB/T 12727-1991 Qualification of electrical items of the safety systems for
nuclear power generating stations
GB/T 13625-1992 Seismic qualification of electrical equipment of the safety
system for nuclear power plants
GB/T 17626.2-2006 Electromagnetic compatibility (EMC) - Testing and
measurement techniques - Electrostatic discharge immunity test
GB/T 17626.3-2006 Electromagnetic compatibility - Testing and
measurement techniques - Radiated radio-frequency electromagnetic field
immunity test
GB/T 17626.4-2008 Electromagnetic compatibility - Testing and
measurement techniques - Electrical fast transient/burst immunity test
GB/T 18271.2-2000 Process measurement and control devices - General
methods and procedures for evaluating performance - Part 2: Tests under
reference conditions
GB/T 18271.3-2000 Process measurement and control devices - General
methods and procedures for evaluating performance - Part 3: Tests for the
effects of influence quantities
NB/T 20001-2013 Fabrication rules for mechanical components of PWR
nuclear island
NB/T 20002-2013 (All parts) welding code for mechanical components of
PWR nuclear islands
NB/T 20019-2010 Ageing, screening, and derating rules of electronic
elements and devices in safety class instrument and control equipment of
nuclear power plants
NB/T 20069-2012 Performance monitoring test of instrumentation channels
important to safety in nuclear power plants
NB/T 20149-2012 Qualification procedure for pressure transmitter important
to safety of nuclear power plants
EJ/T 564-2006 Requirements for packaging, transportation, handling,
receiving, storing, maintaining nuclear power plant items
JJG 882-2004 Pressure transmitter
HAF 603 (2007) Management provisions for welding operator qualification
of civil nuclear safety equipment
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Error
The algebraic difference between the measured value and the true value of
the measured variable.
Note: When the measured value is greater than the true value, the error is a
positive value. The error is usually expressed as a percentage of the
corresponding ideal range.
[GB/T 18271.1-2000, definition 3.8]
3.2
Accuracy
6 Technical requirements
6.1 General performance requirements
6. 1.1 Basic performance
6.1.1.1 Basic error
The basic error of the transmitter shall include the hysteresis and dead band
under certain conditions, which shall be at least grade 0.5. The test method is
carried out in accordance with the requirements of 7.3.1.
Note 1: The basic error is expressed as a percentage of the transmitter range.
Note 2: When the transmitter has a field indicator, its error is not included in the
transmitter's error.
6.1.1.2 Repeatability error
The repeatability error of the transmitter shall not exceed 1/2 of the absolute
value of the basic error. The test method is carried out in accordance with the
requirements of 7.3.2.
6.1.1.3 Functional accuracy
The functional accuracy of the transmitter shall be calculated according to the
sum of square roots of the errors produced by various influences. Except for
special requirements from users, its value shall not be greater than 2% under
normal operating conditions.
6.1.1.4 Response time
The response time required by the pressure transmitter shall be determined
according to the system function requirements. Except for special requirements
from users, it shall not be greater than 1.2s (at 90%).
6.1.2 Electrical performance
6.1.2.1 Insulation resistance
The insulation resistance between the output terminal of the transmitter and the
housing shall not be less than 100 MΩ. The test method is carried out in
accordance with the requirements of 7.3.12.
6.1.2.2 Insulation strength
The pressure transmitter shall be subjected to insulation strength test under
various operating environment conditions, without breakdown, flashover or
0.25%/6.9 MPa of the range. The test method is carried out according to the
requirements of 7.3.9.
6.1.3.7 Impact of one-way overload
Enter the maximum working pressure into the negative (or positive) cavity of
the differential pressure transmitter. After the pressure is removed, the change
in its lower limit value shall be corrected by zero adjustment.
Enter the maximum overload pressure for the relative pressure transmitter and
the absolute pressure chamber. After the pressure is removed, it will not cause
a permanent drift of more than ± 0.5% on the calibration curve.
The test method is carried out in accordance with the requirements of 7.3.10.
6.1.3.8 Impact of ambient temperature
When the ambient temperature is from 20 °C ± 2 °C to -25 °C ~ 70 °C or any
other temperature in the specified temperature range, the impact on accuracy
shall meet the requirements of 6.1.1.3 for the functional accuracy through
calculation. For remote capillary pressure transmitters, the impact of ambient
temperature is determined by the manufacturer. The test method is carried out
in accordance with the requirements of 7.3.5.
6.1.3.9 Humidity impact
Under the conditions of temperature of 40 °C ± 2 °C and relative humidity of 91%
~ 95%, the insulation resistance of the transmitter shall not be less than 2MΩ;
meanwhile its temperature influence and residual change shall meet the
requirements of 6.1.3.8. The test method is carried out in accordance with the
requirements of Chapter 6 of GB/T 18271.3-2000.
6.1.3.10 Impact of output load
When the load resistance changes from the minimum value to the maximum
value as specified by the manufacturer, the change of its output signal shall not
exceed one half of the basic error. The test method is carried out in accordance
with the requirements of 7.3.8.
6.1.3.11 Impact of mechanical vibration
Except for the special requirements of the user, under the mechanical vibration
of the frequency range of the transmitter of 10 Hz ~ 60 Hz, the peak amplitude
of 0.07 mm, the frequency range of 60 Hz ~ 150 Hz, the acceleration of 9.8
m/s2, the change of output signal shall not exceed 1/2 of the basic error.
The test is carried out at 50% of the maximum range according to the
requirements of Chapter 7 of GB/T 18271.3-2000.
environment. For the related requirements of electromagnetic compatibility test,
for pressure and differential pressure transmitters, it shall at least carry out
electrostatic discharge immunity test, radio frequency electromagnetic field
radiation immunity test, electrical fast transient pulse group immunity test; the
severity level of the test shall be at least level 2. If the user has special
requirements, it is defined in the technical specifications.
The test method is carried out in accordance with the requirements of 7.3.17.
6.1.7 Ripple
If the user has no special requirements, the ripple value in the output signal of
the transmitter shall not exceed 0.1% of the range. The test method is carried
out in accordance with the requirements of 7.3.4.
6.1.8 Impact of accelerated working life test
After the transmitter has input alternating signals for 105 cycles, the change of
lower limit value and range shall not exceed the absolute value of the basic
error limit of the maximum range.
The test method is carried out in accordance with the requirements of Chapter
23 of GB/T 18271.3-2000.
6.1.9 Shift
The functional accuracy of the transmitter after the range shift shall meet the
functional accuracy requirements in 6.1.1.3.
The test method is carried out in accordance with the requirements of 7.3.14.
6.2 Nuclear safety-related performance requirements
6.2.1 Aging impact
The transmitter shall be subjected to aging test according to NB/T 20149-2012.
After the test, it shall be adjusted to meet the basic error requirements.
6.2.2 Irradiation impact
For the transmitters important to safety installed in a containment, they shall be
able to withstand a radiation test with a cumulative dose of 6 x 105 Gy in an
accident environment. Except for the special requirements of the user, the
maximum allowable error during and after the test shall not exceed ± 8% of the
maximum range.
The test method is carried out according to the requirements of NB/T 20149-
2012.
the reactor coolant. If the user has other special requirements, it shall be
clarified in the technical specifications.
6.3.1.4 Material procurement and inspection
When outsourcing basic materials (such as sheet metal, Bourdon pipe),
manufacturers need to prepare technical specifications for procurement, use
materials standards that meet the contract requirements or are agreed upon,
meanwhile meet the following requirements:
In addition to the standard and necessary inspections, the following tests are
required:
a) Complete melting chemical analysis and composition analysis (C, Cr, Ni,
Mo);
b) Mechanical test: For the parts that need to bear the load, it shall carry out
the yield strength and Charpy V-notch impact strength test at 20 °C (when
the size of the base material is allowed for testing)
c) It shall perform the ultrasonic inspection of rods with a diameter greater
than 50 mm, perform the liquid penetration inspection of rods with a
diameter less than 50 mm but greater than 25 mm.
For acceptance criteria, see NB/T 20001-2013.
6.3.2 Welding
For the welding material procurement, welding process qualification and
welding of the transmitter, see NB/T 20002.1 ~ 7-2013. Welders and welding
operators shall be qualified and assessed in accordance with HAF 603 (2007).
6.3.3 Installation and protection
6.3.3.1 Impact of installation
The transmitter's detection diaphragm is set to the normal working position
when it is perpendicular to the horizontal plane; it is tilted by 10° from front to
back and left to right at normal working position. After adjusting the zero point,
the lower limit value and upper limit value shall comply with the basic error
requirements. The test method is carried out in accordance with the
requirements of 7.3.11.
6.3.3.2 Seal protection level
The dustproof and waterproof protection level of the transmitter’s housing shall
at least meet the requirements of IP55 as specified in GB 4208-2008.
and range immediately after the test. Long-term drift is the change of range and
he the lower limit of the range before and after the test.
7.3.4 Ripple test
The ripple test is performed on load resistances of 100 Ω and 500 Ω. When the
input value is 10%, 90%, and the midpoint of its range, measure the output
ripple content.
7.3.5 Test of impact of ambient temperature
The test is carried out in a temperature control box. The test temperature
sequence is: starting from 20 °C to the lower limit and upper limit of the selected
ambient temperature. Each temperature range is specified by the manufacturer.
The tolerance of each temperature range is ± 2 °C; the temperature is
maintained for 3 hours, so that the internal temperature of the transmitter is
thermally stable. Measure the output signal value at each temperature point, as
well as the change of the output signal of the transmitter at 20 °C before and
after the test (i.e. residual changes).
7.3.6 Response time test
The test of the response time of the transmitter is performed in accordance with
7.1 of NB/T 20069-2012. If the user specifies the test method and parameters
of the response time, it shall be performed according to the user's requirements.
7.3.7 Test of power supply change
The test is performed at two points of 10% and 90% of the range. When the
load resistance is 100Ω, the voltage is directly changed from the minimum
voltage value corresponding to the 100 Ω load to 45 V DC or the voltage change
range required by the user, measure the change of the output signal.
7.3.8 Output load test
The test is performed at the 50% point of the range. When the voltage is 45 V
DC, the change of the output signal is measured when the load resistance
changes from the minimum to the maximum load.
7.3.9 Test of impact of static pressure
Verification of the impact of transmitter’s static pressure shall be performed in
accordance with 6.2.3.5 of JJG 882-2004.
7.3.10 Unidirectional overload test
For differential pressure transmitters, first enter the specified working pressure
into the nega...