NB/T 20149-2012Qualification Procedure for Pressure Transmitter Important to Safety of Nuclear Power Plants (English PDF)

3.1 Pressure transmitter

The instrument that converts the process variables (pressure, pressure difference, liquid level, flow) into 4 mA ~ 20 mA standard electrical signals

3.2 Gauge pressure (or absolute pressure) transmitter

Transmitter whose output electrical signal is proportional to gauge pressure (or absolute pressure) applied to the pressure tap.

3.3 Differential pressure transmitter

The transmitter whose output electrical signal is proportional to the pressure difference between its two pressure taps.

3.4 Static pressure

Static pressure; differential pressure transmitter.

Gauge or absolute pressure applied to a pressure tap of the transmitter.

3.5 Gauge pressure; absolute pressure

The pressure applied to the pressure tap of the transmitter for gauge pressure (or absolute pressure).

3.6 Influence quantities

The quantity that is not measured but can affect the measurement result.

4.1 General requirements

The qualification of the pressure transmitter shall prove that during the life of the qualification, under the environmental conditions of the design basis accident, the pressure transmitter important for safety has the characteristics of implementing the safety functions specified in the technical specifications (including insulation resistance, accuracy, response time).

4.2 Basic requirements for qualification tests

Each qualification test of the pressure transmitter shall be performed on the same type of pressure transmitter. The test sample shall be consistent with the actual transmitter in terms of design, material and manufacturing process. The test conditions shall meet or exceed the most severe environmental and operating conditions that may actually be experienced.

4.3 Qualification test documents

The qualification test results of the pressure transmitter shall be documented as evidence that the pressure transmitter can implement its safety function during the qualification life period and design basis accident period.

5.1 Basic requirements

The qualification of the pressure transmitter shall first compile the applicable qualification test program, detailing the inspections, tests, performance indicators, acceptance criteria, required analysis as required by the test sample's qualification test to prove that the pressure transmitter implements its safety function.

5.2 Description of qualification device

5.2.1 Identification of device

It shall detail the type, manufacturer, procurement technical specifications and manufacturing related documents of the pressure transmitter to be qualified (including descriptions of functional and structural characteristics, drawings, operation and maintenance manuals, material descriptions, relevant standard, specifications).

5.3 Qualification test conditions

5.3.1 Test conditions during normal and abnormal operation

The qualification test program of the pressure transmitter shall determine the magnitude of the test conditions (including rated values and limit values) and their expected duration during normal and abnormal operation of the power plant. These conditions include at least the following. […]

5.3.2 Test conditions for design basis accidents

The qualification test program of the pressure transmitter shall determine the simulation test conditions during and after the following design basis accidents, as well as the duration required to implement the safety function. These conditions include changes in temperature, pressure, radiation dose over time, chemical conditions, seismic loads, power supply surges.

5.4 Qualification life goals

The qualification test program shall, based on the power plant's management requirements and the pressure transmitter's technical specification requirements, determine the target value of pressure transmitter's qualification life. If the equipment specification does not determine the qualification life target, the qualification test program shall determine the qualification life target of the pressure transmitter according to GB/T 12727.

5.5 Qualification margin

In order to ensure that the pressure transmitter has satisfactory performance under severe environmental and operating conditions, the qualification test shall consider the qualification margin.

5.6 Monitoring of functional characteristics during test

The qualification test program shall determine the electrical performance and functional characteristics (insulation resistance, accuracy, and / or response time) to be measured during each test of the pressure transmitter and at the end of the test and after the equipment is restored.

5.7 Selection of test samples

Some test items of the pressure transmitter's qualification test may not be conducted on the same test sample. The test shall determine the number of test samples based on the installation location of the pressure transmitter (inside the containment, in the equipment compartment, in the containment annular space or outside the containment) as well as the configuration of the test item.

5.10 Test sequence

The qualification test of the pressure transmitter shall be carried out in accordance with the test sequence requirements as specified in GB/T 12727.

The test program shall formulate detailed test steps and sequences for transmitters of different types of qualification requirements; the test sequence's configuration shall be such that the test samples are in the most severely degraded state at the end of the qualification life. Table 1 lists the test sequences for reference.

5.11 Acceptance criteria

The test program shall determine the acceptance criteria for the electrical performance and functional characteristics of the test samples at each stage of the qualification test based on the performance requirements specified in the technical specifications for equipment purchase.

5.12 Evaluation of test process

The values of functional characteristics monitored by each test during the qualification test shall be compared with the acceptance criteria. If a deviation occurs, it shall be based on the analysis and evaluation of the acceptance criteria to determine whether to continue or abort the test.

6.1 Compliance inspection and test preparation

6.1.1 Compliance inspection

Prior to the start of the qualification test, it shall perform the compliance inspection of the test samples and relevant documents (including material qualification certificates, strength calculations, etc.), to confirm that the samples to be tested represent pressure transmitters that require on-site installation (see Appendix A).

6.1.2 Test preparation

6.1.2.1 Adjustment of pressure transmitter

Each test of the pressure transmitter's qualification test shall be conducted after the zero point and sensitivity are adjusted in accordance with the operating instructions of the pressure transmitter. Zero point and sensitivity are adjusted as follows. […]

6.1.2.2 Power supply and load resistance

The power supply voltage used for testing and measurement is equal to the rated value given in the technical specifications; the ripple factor of the power supply is less than 0.1% of the power supply voltage; the load resistance value of the pressure transmitter is equal to the rated value specified in the identification file.

6.2 Reference test

6.2.1 Dielectric strength measurement

6.2.1.1 Test conditions

The test is conducted by the use of an AC sine wave voltage which has a rated frequency of 50 Hz. The test voltage is as shown in Table 2.

The test shall be conducted under normal atmospheric conditions, see JJG 882.

The pressure transmitter, together with the electrical connector, is grounded as follows. […]

6.2.1.2 Test

Disconnect the power supply of the pressure transmitter. Short-circuit the power terminal and the output terminal respectively. Measure the dielectric strength between the power terminal and the ground terminal (housing), the power terminal and the output terminal, the output terminal and the ground terminal (housing) on the withstanding voltage tester.

6.2.1.3 Acceptance criteria

There shall be no breakdown or arcing in 1 minute.

6.2.2 Measurement of insulation resistance

6.3 Test of influence quantity limit

6.3.1 Dry heat test

6.3.1.1 Overview

The purpose of this test is to verify the adaptability of the dry heat effect of the pressure transmitter during transportation and storage.

6.3.1.2 Test conditions

This test shall be carried out in accordance with the provisions of GB/T 2423.2 (Test B).

6.3.1.3 Measurement

After 4h restoration, it shall carry out the following measurements.

6.3.1.4 Acceptance criteria

If the technical specifications do not specify clearly, it may adopt the following acceptance criteria.

6.3.2 Low temperature test

6.3.2.1 Overview

The purpose of this test is to verify the low temperature adaptability of the pressure transmitter during transportation and storage.

6.3.2.2 Test conditions

This test shall be carried out in accordance with the provisions of GB/T 2423.1 (Test A).

6.3.5 Mechanical shock resistance test

6.3.5.1 Overview

The purpose of this test is to simulate the random impact adaptability that the pressure transmitter may be subjected to during use or transportation.

6.3.5.2 Test conditions

This test shall meet the requirements of GB/T 2423.5.

The test is carried out under normal atmospheric conditions. The equipment is not energized; it is fixed on a rigid bracket according to the on-site fixing method of the pressure transmitter. The impact force shall be applied vertically on each plane of the three reference axis of the pressure transmitter.

7.1 Qualification test record

Qualification test records shall include at least.

a) The model, identification and number of the device under test;

b) The name, model and number of the test device, equipment and instruments used;

c) Detailed data and recording curves of test conditions;

d) Record (or record form) of each test;

e) Abnormal conditions that occurred during the test;

f) Tester's signature and date.

7.2 Qualification test report

The qualification test report shall include at least. […]