Auxiliary Feedwater Valve Control for Steam Generator Water Level
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Solution Overview
Problem
The auxiliary feedwater system in pressurized water reactors lacks automatic control over the water level in the steam generator, relying on manual operator intervention, which increases operational burden during plant outages and accidents.
Innovation Solution
An auxiliary feedwater valve control apparatus that automatically adjusts the aperture of the auxiliary feedwater valve based on pre-measured opening/closing operation speeds, driving times, and temperature conditions, using a microcomputer system to calculate deviations and set optimal driving cycles and times to maintain target water levels, thereby reducing operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual operation is used to control the auxiliary feedwater valve, then the operator can adjust the water level, but the operational burden increases and automation is reduced
Solution Approach 1:
The control apparatus enables the system to control itself automatically. The microcomputer executes pre-stored programs to automatically adjust the auxiliary feedwater valve aperture based on water level sensor feedback, eliminating the need for manual operator intervention and achieving self-service operation.
Solution Approach 2:
The system implements closed-loop feedback control where water level sensors continuously monitor the steam generator water level, compare it with the target level, and automatically adjust the valve aperture through the microcomputer to maintain the desired water level, creating a self-regulating feedback mechanism.
2Measurement precision
If the auxiliary feedwater valve operates frequently to maintain precise water level, then water level control precision improves, but valve wear and system complexity increase
Solution Approach 1:
The microcomputer stores multiple pre-calculated control programs and parameters before operation. When a water level deviation is detected, the system selects and executes the appropriate pre-prepared control strategy, avoiding the need for complex real-time calculations and simplifying the control system architecture.
Solution Approach 2:
The control system dynamically adjusts the valve aperture based on real-time water level conditions. The microcomputer modifies control parameters on-the-fly by selecting from pre-stored programs, enabling adaptive control that maintains precision without requiring a permanently complex system structure.
Data Source
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AI summary
An auxiliary feedwater valve control apparatus (1) of a steam generator (103) that operates an auxiliary feedwater valve (123) in an auxiliary feed water system provided as a protective system of a main feed water system that feeds secondary cooling water to a steam generator (103), includes a water-level detection means (125) that detects a water level of secondary cooling water in the steam generator (103), a water-level-deviation calculation means (3) that calculates a deviation between a preset target water level and a water level detected by the water-level detection means (125), a valve-operation setting means (4) that sets an aperture of the auxiliary feedwater valve (123) corresponding to a deviation of the water level, and a valve drive means (5) that outputs a signal for driving the auxiliary feedwater valve (123) corresponding to setting by the valve-operation setting means (4).