Steam Generator Flow Resistance Adjusting Unit
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Solution Overview
Problem
In steam generators used in nuclear power plants, the corrosion or damage of heat-transfer tubes leads to increased flow resistance and reduced heat recovery efficiency, making it difficult to maintain efficient operation and manufacturing costs, especially when replacing old generators with new ones.
Innovation Solution
A steam generator design that includes a flow resistance adjusting unit in the inlet or outlet nozzles, allowing for the adjustment of flow resistance by using detachable plates, a movable gate, or cylindrical pipes, which can be controlled based on measured water volumes to optimize the flow rate of primary cooling water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat-transfer tubes are closed due to corrosion or damage, then reliability of the steam generator is maintained, but flow resistance increases and heat recovery efficiency decreases
Solution Approach 1:
The invention changes the flow resistance parameter by adjusting the opening degree of the flow resistance adjusting gate. When heat-transfer tubes are closed, the gate opening is reduced to increase flow resistance, compensating for the reduced flow path area and maintaining appropriate cooling water flow rate and heat recovery efficiency.
2Loss of energy
If steam generator is replaced after 20-30 years of use, then heat recovery efficiency can be restored, but manufacturing cost increases and project complexity increases
Solution Approach 1:
The invention introduces a dynamic flow resistance adjusting gate that can be operated during the steam generator's service life. This allows the flow resistance to be dynamically adjusted as heat-transfer tubes are progressively closed, extending the operational life of the steam generator without replacement and avoiding high manufacturing costs.
Solution Approach 2:
The flow resistance adjusting gate enables the steam generator to self-adjust and maintain optimal performance autonomously. By monitoring heat transfer performance and adjusting the gate opening accordingly, the system can maintain heat recovery efficiency without external intervention or replacement, reducing project complexity and cost.
3Device complexity
If number of heat-transfer tubes is reduced for downsizing, then device complexity is reduced, but flow resistance increases and heat recovery efficiency decreases
Solution Approach 1:
When the number of heat-transfer tubes is reduced for downsizing, the flow resistance adjusting gate is used to modify the flow resistance parameter. By adjusting the gate opening degree, the system compensates for the reduced flow path area, maintaining appropriate cooling water flow rate and heat recovery efficiency despite the simplified structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables the adjustment of flow resistance to maintain or enhance heat recovery efficiency, even with a reduced number of heat-transfer tubes, thereby stabilizing the steam generator's performance and reducing the need for frequent replacements.
Implementation Method 1
the flow resistance of the steam generator increases, and the flow rate of the primary cooling water flowing in the heat-transfer tube group is decreased
Implementation Method 2
the heat of the primary cooling water is transferred to the secondary cooling water flowing outside the heat-transfer tubes, thereby generating the steam
Implementation Method 3
heat exchange is performed between the primary cooling water (hot water) flowing inside the plurality of heat-transfer tubes and the secondary cooling water (cold water) circulating inside the barrel
Data Source
AI summary
In a steam generator, a flow resistance adjusting unit for a primary cooling water is provided in an inlet nozzle provided at an incoming water chamber or an outlet nozzle provided at an outgoing water chamber.