What Is a Control Room?

With the implementation of China's clean energy strategy. The status of nuclear power plants is constantly emerging, and it is gradually becoming an indispensable part of China's power industry. The control room of a nuclear power plant provides an earthquake-resistant, habitable workplace for operators of nuclear power plants.

Basic Information

Chinese name: Control room

Foreign name

Operators of nuclear power plants monitor and control the operation process of nuclear power plants in the control room through DCS control systems and other equipment to ensure the safe and stable operation of nuclear facilities. The control room panel is the main carrier of the man-machine interface of the DCS control system in the control room of the nuclear power plant, and its shape and structure design work is an important part of the entire nuclear power plant DCS system design.

DCS Composition of DCS control panel in control room of nuclear power plant

The composition of a DCS system tray in a typical nuclear power plant control room generally includes:

· Computerized operator console: Generally installed with several operator workstations (OWP), each set of OWP is equipped with 3 to 5 displays, host computer, keyboard mouse trackball, etc. At the same time, the operator console is also equipped with communication equipment and network equipment.

· Backup disk (BUP): BUP serves as a backup for the nuclear power plant information monitoring and control system (KIC). In the event of KIC failure, the backup disk can help safety engineers evaluate the safety status of the entire plant and monitor the main safety parameters and safety systems. status. In addition, periodic tests can be performed on the backup disk equipment to ensure that the equipment on the backup disk is available.

· Emergency operation console (ECP): In emergency situations, the operator can use the emergency operation equipment on the ECP to perform manual shutdown and special safety facilities system-level drive and other protective actions to ensure the safety of the entire plant.

· Large-screen display panel.

DCS The basic elements of the control panel DCS system tray design

The basic elements of the design of the outer structure of the DCS system tray in the control room of a nuclear power plant

The basic elements of the design of the DCS system tray in the control room of a nuclear power plant generally include:

· Classification of pallet equipment;

· Basic mechanical structure design of the table;

· Taiwan human factors engineering and appearance design;

Identification of the table.

Table equipment classification

The classification of the equipment in the control room of the nuclear power plant includes: safety level (1E / NC), earthquake resistance level (Class I, II, etc.), quality assurance level (QA1, QA2, QA3, QNC, etc.).

The table below is a general classification of the equipment in the control room of a nuclear power plant for reference.

Classification of control panel equipment in general nuclear power plants

Mechanical design

Anti-seismic

The seismic level of the pan equipment is seismic class I, and the seismic identification is performed in accordance with the regulations of RCC-E 2005 (B4000), HAF J0053 and GB 13625. The platform structure meets the seismic requirements of the response spectrum of the corresponding floor.

2. Equipment structural characteristics

The trays are all incoming lines, and their installation is fixed to the embedded parts of the plant by bolts.

When designing the structure of the disk table, design chamfers for the front edge, side edges, etc. of the disk table surface, and consider leaving sufficient space to facilitate:

-Installation and arrangement of pallet equipment;

-Installation and maintenance, requiring maintenance doors on the front and back of the pan;

-Wiring, sinks and wiring in the panel;

-Heat dissipation of equipment in the tray.

The structural design will consider the installation of the following third-party equipment in the tray:

-communication device

-Radiation monitoring systems, etc.

3.Protection level

Disk protection level is not lower than IP30.

Ventilation inside the tray

The inside of the tray is cooled by natural ventilation. Avoid installing fans. Open blinds on the back of the tray to form natural convection to ensure the normal heat dissipation of the equipment in the tray.

The table can withstand the environmental conditions encountered during normal and abnormal operation.

The design will consider the operating temperature of the equipment installed inside the tray to ensure that when it is at the highest ambient temperature, the operating temperature of the equipment does not exceed the rated value.

4. Noise

The control room environment will ensure comfortable working conditions for the control room personnel. When designing the tray, the influence of the equipment noise (if any) in the tray will be fully considered, and the noise value in the tray area will be limited to the standard range.

The tray design minimizes the influence of the equipment in the tray on the noise of the main control room. If necessary, a sound insulation cover can be designed on the ventilation louver. The sound insulation cover uses low-smoke, halogen-free, and flame-retardant lightweight materials.

Electrical Design

Isolation

In accordance with different safety levels, the electrical equipment, cable paths, wiring, and power supply of the tray equipment are electrically and physically isolated to ensure that common causes of failure will not affect redundant cable connections of different safety levels at the same time.

Here are the isolation scenarios considered:

-Isolation of different redundant equipment;

-Isolation of different security levels;

-Isolation of third-party equipment;

-Isolation of shielding equipment.

The isolation device used to isolate safety and non-safety equipment is powered by the safety level.

When the panel 1E control equipment is used for different safety levels, relay isolation is used.

2. Power

The power required for the table is provided by the DCS side at the same level. To meet the important requirement of redundant power supply, all power supplies have at least two independent power paths. When one power supply fails, the power supply inside the tray will automatically switch.

The power supply of the tray will consider the power requirements of third-party equipment installed in the tray. If necessary, it will install electrical equipment such as terminals and fuses required for power supply.

3. Ground

The inside of the panel is separated by the protective ground and shielded ground copper bars, and the single-point grounding principle. The grounding copper bar is installed at the bottom position inside the tray. The grounding copper bar is shorted when the tray is spliced.

"Protected Ground" connections

The protective grounding copper bar of the disk table is fixed on the disk table body through uninsulated bolts. The metal shell of the equipment installed on the tray is reliably connected to the protective ground bus. The tray door will be connected to the tray body through a flexible copper cable. The protective ground cable is separated from the shielded ground cable path. The grounding resistance to ground measured in the pan should be no more than 4 ohms; the cross section of the grounding conductor is 16mm².

"Shield Ground" connection

The shielding ground copper bar is fixed on the disk table through insulating bolts, and the shielding ground is insulated from the disk table body. The shield of the field measurement or control cable is grounded only on the DCS cabinet side. The cable shielding layer between the terminal in the panel and the equipment on the panel is connected to the shielded ground copper bar through the terminal. The grounding resistance to ground measured in the pan should be no more than 4 ohms; the cross section of the grounding conductor is 16mm².

The tray is designed to resist electromagnetic interference that may occur in a typical industrial environment. To reduce interference, methods that can be applied include: grounding, using low-voltage components, physical separation and electrical isolation, shielding sensitive components or interference sources, and so on.

The shielded cable connection is used between the panel device and the terminals inside the panel. A single panel device should share a multi-core shielded cable as much as possible. The cable shield is connected to the empty terminal module. After each terminal module is shorted, it is connected to the shielded ground copper bar.

In order to prevent electromagnetic interference signals, different types of cables in the tray are isolated. The power and signal cables are isolated by connecting independent terminal modules and different wiring paths, following the rules:

· The wiring of different safety levels must be separated;

220V AC wiring must be separate from 24V DC wiring.

Shielded cables need to cover at least 80% effectively. The cable shield connection terminal is adjacent to the signal connection terminal.

4. Lighting

The table is equipped with an automatic lighting system for easy maintenance.

5. Pantai human factors engineering and shape design

The shape of the table is strictly in accordance with the requirements of human factors during the design process to improve the man-machine efficiency of the entire control room. NUREG-0700 is an important reference standard for the application of human factors, from which all relevant standard requirements are extracted for the design and evaluation criteria of human factors engineering of Pantai; Section 11.1.1 of the standard and 11.1. The relevant standards for the 2-section sitting console are the key points of reference. At the same time, reference was made to the "Chinese Adult Human Body Dimensions" (GB10000-1988) during the design process in order to design an operation panel suitable for the Chinese body structure.

In addition to the shape and size, the internal structure of the tray table and the installation of the equipment in the tray are fully designed with human factors in mind. In terms of maintenance and operation, the impact of personnel on the safety or availability of the reactor is avoided.

6. Identification of the table

The safety-grade disk table needs to pass the qualification test to prove that it meets the requirements of nuclear safety-grade equipment. The qualification test items mainly include:

EMC test; environmental test; aging test; long-term operation test; seismic identification. ^[1]