Once-Through Steam Generator Pressure Control via Segmented Channels

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Solution Overview

Problem

Existing steam generator systems in nuclear power plants face challenges in controlling outlet pressure due to mismatched response characteristics between the once-through steam generator and the reactor core, leading to instability and high requirements for control system execution.

Innovation Solution

A once-through steam generator pressure control system is introduced, comprising a pressure deviation control channel, a steam-water flow deviation control channel, and a load demand control channel, which work together to measure and adjust outlet pressure and flow values, and control valve openings to achieve stable pressure control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure deviation and steam-water flow deviation control is used, then outlet pressure control is achieved, but high requirements for execution mechanism and large valve action amplitude occur, adversely affecting system stability

Engineering Contradiction:
Improveoutlet pressure control precisionVSAvoidsystem stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The control system is segmented into three independent control channels: pressure deviation control channel, steam-water flow deviation control channel, and load demand control channel. Each channel processes specific control signals separately before integration, allowing precise control while distributing the control burden to maintain system stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system dynamically adjusts valve positions based on real-time pressure deviations and flow deviations. The control channels continuously monitor and adjust the water supply regulating valve group positioning, enabling adaptive response to changing system conditions while maintaining stability through coordinated control actions.

Inventive Principle:
Principle #15Dynamics

2Speed

If quick response characteristic of once-through steam generator is used, then rapid pressure adjustment is achieved, but mismatching with reactor core response lag occurs, causing control difficulties

Engineering Contradiction:
Improvepressure adjustment speedVSAvoidcoordination with reactor core response
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The control system implements feedback mechanisms where the pressure deviation control channel and steam-water flow deviation control channel continuously monitor outlet pressure and flow conditions. This feedback allows the system to adjust water supply in real-time, coordinating the quick response of the steam generator with the slower reactor core response through continuous monitoring and adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system changes operating parameters dynamically by adjusting water supply flow rate through the water supply regulating valve group. By modifying flow parameters based on pressure and flow deviations, the system adapts the quick response characteristic to match the reactor core's slower response timeline.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4257878B1Steam generator system, steam generator pressure control system, and control method therefor
Publication Date: 2025.02.19 CHINA NUCLEAR POWER TECH RES INST CO LTD
  • EP4257878B1 patent drawingFigure 1~2
  • EP4257878B1 patent drawingFigure 3~4
  • EP4257878B1 patent drawingFigure 5~6

AI summary

Disclosed are a steam generator system, a steam generator pressure control system, and a control method therefor. The steam generator pressure control system comprises a first control module for obtaining a pressure deviation value; a second control module for measuring and calculating a flow difference value between an outlet flow value and an inlet flow value, and then adding the flow difference value and the pressure deviation value together to obtain a first opening degree value for controlling a first valve of a water supply regulation valve group; and a third control module for measuring a steam intake pressure value of a steam turbine, and comparing the steam intake pressure value with a preset reference threshold value, so as to obtain a second opening degree value for controlling a second valve of the water supply regulation valve group. In the steam generator system, the steam generator pressure control system, and the control method therefor of the present invention, the opening and closing conditions of the water supply regulation valve group is controlled by means of a first control module, a second control module and a third control module, such that a steam generator is controlled, thereby satisfying the requirements for both coarse regulation and fine regulation.