Steam Generator Tube Support Plate for Compact Flow Channels

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Solution Overview

Problem

Existing support plates for U-shaped heat transfer tubes in PWR nuclear power plants face challenges in compact arrangement, fluid circulation, and sludge deposition, leading to increased fluid resistance, stress concentration, and potential evaporation and corrosion of the tubes.

Innovation Solution

A support plate with three-leaf plum blossom-shaped holes and a specific included angle configuration, along with a tube gallery area, allows for compact arrangement and enhanced fluid circulation, reducing stress concentration and enabling effective sludge removal during maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If round holes are used in the support plate to facilitate fluid circulation, then fluid can circulate through the support plate, but the support plate cannot be compactly arranged and the fluid circulation area is insufficient, leading to increased fluid flow resistance

Engineering Contradiction:
Improvefluid circulationVSAvoidarrangement compactness
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs curved arc-shaped holes instead of straight or circular holes in the support plate. The arc-shaped configuration optimizes fluid flow paths while maintaining structural integrity, allowing for compact arrangement of support plates without compromising circulation area. The curved geometry naturally guides fluid flow and reduces resistance while enabling tighter spacing between adjacent support plates.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If round holes are used in the support plate, then fluid circulation is facilitated, but the hole bridge structure has insufficient continuity, causing stress concentration and structural fatigue damage

Engineering Contradiction:
Improvefluid circulationVSAvoidstructural continuity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The arc-shaped holes with curved boundaries create more continuous hole bridge structures between adjacent holes compared to circular holes. The curved geometry distributes stress more evenly across the plate, reducing stress concentration at sharp corners while maintaining adequate fluid circulation paths.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If the support plate lacks washing capability, then the structure remains simple, but sludge deposited on the support plate cannot be washed and removed effectively, leading to partial evaporation of the U-shaped heat transfer tube

Engineering Contradiction:
Improvestructure simplicityVSAvoidsludge deposition
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The arc-shaped holes facilitate sludge removal by creating smooth, curved surfaces that prevent sludge accumulation and enable effective washing during maintenance. The curved geometry allows washing fluids to flow more effectively across the support plate surface, removing deposited sludge that would otherwise cause evaporation issues.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The solution enables compact tube arrangement, improved fluid circulation, reduced evaporation risk, and enhanced thermal and hydraulic performance by minimizing stress concentration and facilitating sludge washing, thus improving the safety and efficiency of the steam generator.

Implementation Method 1

the side edge and the top edge of the three-leaf plum blossom-shaped hole and the tube wall of the U-shaped heat transfer tube enclose a heat exchange fluid channel at outer side of the U-shaped heat transfer tube

Methodology Applied
Scientific EffectFluid circulation: Convection

Implementation Method 2

the included angle of connection line of the three-leaf plum blossom-shaped holes and side edge corresponding thereto is α, and 0°<α≤13°... reduced stress concentration and structural fatigue damage

Methodology Applied
Scientific EffectStress distribution:

Data Source

PatentEP3805686B1Support plate for u-shaped heat transfer tube of steam generator of nuclear power plant and steam generator thereof
Publication Date: 2026.02.04 CHINA NUCLEAR POWER DESIGN COMPANY
  • EP3805686B1 patent drawingFigure 1~2
  • EP3805686B1 patent drawingFigure 3
  • EP3805686B1 patent drawingFigure 4~5

AI summary

The present invention discloses a support plate for U-shaped heat transfer tube of steam generator of nuclear power plant including a plate body. The plate body is provided with a number of three-leaf plum blossom-shaped holes extending through the plate body. A hole bridge is formed between two adjacent three-leaf plum blossom-shaped holes. Each three-leaf plum blossom-shaped holes includes a boss edge, a side edge and a top edge. After the U-shaped heat transfer tubes are inserted into the three-leaf plum blossom-shaped holes, the boss edge supports tube wall of the U-shaped heat transfer tube. The side edge and the top edge of the three-leaf plum blossom-shaped hole and the tube wall of the U-shaped heat transfer tube enclose a heat exchange fluid channel at outer side of the U-shaped heat transfer tube. A tube gallery area is formed at a middle portion of the plate body. The tube gallery area is provided with through holes and the three-leaf plum blossom-shaped holes are arranged on two sides of the tube gallery area, wherein and an included angle of connection line of the three-leaf plum blossom-shaped hole and side edge corresponding thereto is α, and 0&lt;α≤13°. Compared with the prior art, the support plate for U-shaped heat transfer tube of steam generator of nuclear power plant according to the present invention make the U-shaped heat transfer tube arranged more compactly, and more U-shaped heat transfer tubes can be arranged on the same area, thereby reducing the overall size and cost of the equipment. The three-leaf plum blossom-shaped hole has a larger heat exchange fluid flow area, ensuring the structural continuity and the strength at the weakest point of the hole bridge structure of the support plate.