Integral PWR Steam Generator Plenum Design
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Solution Overview
Problem
Conventional pressurized water reactors (PWRs) with integral steam generators require active pumping to circulate secondary coolant, increasing complexity and costs due to defined flow paths in shell-and-tube configurations, whereas natural circulation modes are less efficient and require additional components.
Innovation Solution
A PWR design with a pressure vessel divided into upper, lower plenums, and a steam generator plenum, where primary coolant circulates naturally driven by heat, and a steam separator separates secondary coolant phases without active pumping, eliminating defined secondary coolant flow paths and using a steam generator plenum without piping for secondary coolant flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active pumping is used to circulate secondary coolant in shell-and-tube steam generators, then reliable coolant circulation is achieved, but device complexity and manufacturing costs increase due to defined flow paths and piping requirements
Solution Approach 1:
The invention extracts the piping and defined flow path structures from the steam generator, eliminating the complex shell-and-tube configuration. Instead, it uses a plenum chamber where secondary coolant flows freely without constrained pathways, thereby reducing device complexity while maintaining circulation reliability through natural convection currents.
Solution Approach 2:
The steam generator enables self-service by utilizing natural circulation of secondary coolant driven by density differences between heated and cooler regions. The system serves itself without requiring external pumping mechanisms, eliminating the need for complex piping and flow control structures while maintaining reliable coolant circulation.
2Use of energy by moving object
If shell-and-tube steam generator configuration is used, then efficient heat transfer is achieved, but tube mass and manufacturing costs increase
Solution Approach 1:
The invention removes the extensive tube structures from the steam generator design, extracting only the essential heat transfer function. By using a plenum chamber configuration where secondary coolant directly contacts heated surfaces and circulates freely, it achieves efficient heat transfer with dramatically reduced material mass compared to traditional shell-and-tube assemblies.
3Ease of operation
If defined secondary coolant flow paths with piping are used, then controlled coolant circulation is achieved, but ease of manufacture and component interchangeability deteriorate
Solution Approach 1:
The invention extracts all piping and flow path definitions from the steam generator, simplifying the design to a plenum chamber configuration. This dramatically improves ease of manufacture and component interchangeability while coolant flow control is maintained through the natural circulation patterns established by the heated surfaces and density gradients.
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 reduces tube mass by 40-50%, lowers manufacturing costs, simplifies refueling, and enhances component interchangeability, while enabling a natural circulation emergency core cooling system, improving efficiency and reducing operational complexity.
Implementation Method 1
A steam separator is operatively connected with the steam generator plenum to separate secondary coolant in the steam phase from secondary coolant in the water phase
Implementation Method 2
This primary coolant circulation can occur naturally (i.e., natural circulation) driven by the heat generated by the reactor core
Data Source
AI summary
A pressurized water reactor (PWR) includes: a pressure vessel divided into an upper plenum containing primary coolant, a lower plenum containing primary coolant, and a steam generator plenum interposed between the upper plenum and the lower plenum and containing secondary coolant; a nuclear reactor core comprising fissile material disposed in the lower plenum; one or more risers arranged to convey primary coolant upward from the nuclear reactor core to the upper plenum; and a plurality of tubes passing through the steam generator plenum and arranged to convey primary coolant downward from the upper plenum to the lower plenum. A steam separator is operatively connected with the steam generator plenum to separate secondary coolant in the steam phase from secondary coolant in the water phase.