Plate Heat Exchanger Segmentation for Nuclear Residual Heat Removal
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Solution Overview
Problem
Passive residual heat removal systems in nuclear power plants face challenges with flow instability and the bottleneck phenomenon when using plate type heat exchangers, which can lead to pressure boundary damage and inefficient heat transfer.
Innovation Solution
A passive residual heat removal system incorporating a plate type heat exchanger with high-density heat transfer performance, capable of operating under high temperature and pressure, and featuring a closed or partially open flow path design to efficiently circulate cooling fluids while maintaining a pressure boundary, using water cooling, air cooling, or hybrid cooling methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a plate type heat exchanger is used in a passive residual heat removal system, then heat exchange efficiency is improved, but flow instability and bottleneck phenomenon occur
Solution Approach 1:
The plate type heat exchanger is divided into multiple independent flow channels separated by partition walls. This segmentation allows coolant to flow through multiple parallel paths, preventing flow instability and bottleneck phenomena while maintaining high heat exchange efficiency through increased surface area contact between hot and cold fluids.
Solution Approach 2:
Different regions of the heat exchanger plates are designed with varying characteristics - some areas have enhanced turbulence promoters or extended surfaces to improve heat transfer locally, while other regions are optimized for smooth flow to prevent instability. This local optimization resolves the contradiction between efficiency and stability.
2Productivity
If a plate type heat exchanger is used to remove heat efficiently, then heat removal performance is improved, but pressure boundary integrity may be compromised
Solution Approach 1:
A separate secondary coolant loop is introduced as an intermediary between the primary reactor coolant and the heat exchanger. The secondary coolant circulates through the plate type heat exchanger, absorbing heat from the primary coolant without directly contacting it. This mediator approach maintains pressure boundary integrity in the primary system while enabling efficient heat removal through the heat exchanger.
Solution Approach 2:
The heat exchanger design separates primary and secondary coolant paths using partition walls and independent channels. This segmentation ensures that pressure changes in the secondary loop do not affect the primary pressure boundary, maintaining system reliability while achieving high heat removal performance.
3Speed
If cooling fluid circulation is enhanced to remove heat faster, then heat removal rate is improved, but flow instability increases
Solution Approach 1:
The heat exchanger incorporates periodic turbulence promoters or oscillating flow elements that create controlled periodic disturbances in the coolant flow. These periodic actions enhance heat transfer coefficients and increase heat removal rate while preventing chaotic flow instability through regular, predictable flow patterns.
Solution Approach 2:
The system allows dynamic adjustment of flow rates and cooling fluid properties to optimize performance. By dynamically balancing flow velocity and heat transfer efficiency, the system achieves high heat removal rates while maintaining flow stability through adaptive control of operating conditions.
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 system effectively removes sensible and residual heat from the reactor coolant system while maintaining a pressure boundary, enhancing safety and durability during accidents, and mitigating flow instability and bottleneck issues.
Implementation Method 1
a plate type heat exchanger configured to exchange heat between primary system fluid or secondary system fluid... and cooling fluid
Implementation Method 2
a circulation line configured to connect the reactor coolant system to the plate type heat exchanger to form a circulation flow path
Implementation Method 3
cooling fluid introduced from an inside or outside of a containment to remove the sensible heat and residual heat
Data Source
AI summary
The present invention provides a passive residual heat removal system and an atomic power plant comprising the same, the passive heat removal system comprising: a plate-type heat exchanger for causing heat exchange between a primary system fluid or a secondary system fluid which, in order to remove sensible heat from an atomic reactor cooling material system and residual heat from a reactor core, has received the sensible heat and the residual heat, and a cooling fluid which has been introduced from outside of a containment unit; and circulation piping for connecting the atomic reactor cooling material system to the plate-type heat exchanger, thereby forming a circulation channel of the primary system fluid, or connecting a steam generator, which is arranged at the boundary between the primary and secondary systems, to the plate-type heat exchanger, thereby forming a circulation channel of the secondary system fluid.