get a quote

Dayawan Nuclear Power Plant

Complee has professional product design, technical research and development team; complete series of testing and testing equipment; strong mold design and manufacturing team; advanced tooling fixtures and automated production line design and manufacturing capabilities; we provide electrical application solutions for the Qinshan Nuclear Power Plant, Dayawan Nuclear Power Plant, China Kunlun Station, Great Wall Station, and Zhongshan Station in Antarctica, as well as the Yong Sheng Yu Power Station in Inner Mongolia.

We have selected a new type of hydraulic diaphragm metering pump and asynchronous AC motor to replace the original 3 continuous running dosing pumps. Among the three pumps, one is kept as a backup, and the other two receive signals from the original conductivity meter and amine meter. These signals are sent to two PD (Proportional-Derivative) controllers. The PD controller adjusts the output based on the measured values and set target values, performing D control and sending adjustment signals to the frequency converter. The frequency converter outputs the corresponding frequency of AC electricity to drive the asynchronous AC motor, adjusting the motor's speed. This results in a corresponding change in the dosing flow rate, thus controlling the conductivity of the treated water and the amine concentration.

1. Control Methods

Due to the high reliability and availability requirements for nuclear power plants, the upgraded system offers three control modes: manual, semi-automatic, and fully automatic. The control mode can be switched using three position switches. The modes are as follows:

(1) Manual: In this mode, similar to the traditional dosing method, the frequency converter and PD controller are bypassed. The start/stop of the dosing pump is manually controlled by the on-site personnel. By pressing the start button, the pump motor runs at full speed (50 Hz). The dosing flow rate is controlled by adjusting the pump stroke based on the site’s parameters.
(2) Semi-Automatic: In this mode, the PID controller is bypassed. The dosing amount is controlled by adjusting the frequency converter's speed control potentiometer. By changing the motor speed, the dosing flow rate is adjusted accordingly.
(3) Automatic: In this mode, the dosing control is fully automated. The pump starts and stops based on set thresholds, and the PD controller calculates and adjusts the motor speed and on/off status according to the user settings and on-site instrument readings. This ensures the dosing flow rate stays within the required range for the process.

2. Key Equipment Selection

2.1 Controller

Function: Performs PI-D control and sets control targets; sets the automatic start/stop points for the pump.
Model: UDC3300 Controller (Honeywell)
Details:
Input/Output Isolation: Supports various types of input signals such as thermocouples, resistance temperature detectors (RTDs), linear signals, dual-loop inputs, and digital signal inputs.
For this project, the input signal types will be chosen based on the characteristics of conductivity and amine concentration. The linear signal input type is selected.
Output Types: Current output, relay output, open collector output, optional auxiliary current output; isolated auxiliary current output, digital input; SPDT relay for alarm outputs. The system supports various alarm types with flexible grouping and configuration. It also supports RS-422/485 MODBUS and ASCII code for communication. The output signal for the frequency converter will be a 4-20 mA current signal, with linear signal input selected for compatibility with the converter.
Control Mode: The controller supports manual/automatic switching. It has fuzzy logic control and the Accutune II self-adaptive algorithm for overshoot suppression.
Control Precision: The selected controller has a 1/1 resolution and 0.5% full-range output precision.

2.2 Frequency Converter

Function: Adjusts the dosing pump's speed according to the controller's instructions, thereby changing the dosing amount. It also automatically starts/stops the dosing pump based on commands from the controller or manual input.
Model: ACS140 (ABB)
Control Precision: The frequency converter can accurately track the given signal, with an average precision of greater than 1%.
Response: Fast response, with an average delay of less than 9 ms.
Power Supply: Three-phase 380V (+10%), frequency: 50 Hz.
Protection Functions: Includes overcurrent, overvoltage, undervoltage, overheat, input/output short circuit, ground fault, output short circuit, input phase loss, motor overload, and stall protection.