Compact Heat Exchanger Segmentation for Nuclear Cooling
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Solution Overview
Problem
Nuclear power plant heat exchangers with reduced dimensions face mechanical stress due to excessive temperature differences, risking damage and operational failure.
Innovation Solution
A method using a heat exchanger that recirculates water vapor through multiple passages with supercritical carbon dioxide for indirect heat exchange, controlling temperature fluctuations and reducing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the dimensions of the heat exchanger are reduced to fit in the reactor building, then the heat exchanger can be arranged in the confined space, but the temperature difference between the cold fluid and hot fluid becomes excessive, inducing mechanical stresses that may damage the heat exchanger
Solution Approach 1:
The heat exchanger is divided into multiple passes (first passage, second passage, third passage, fourth passage, fifth passage) through which the hot fluid sequentially flows. This segmentation allows the temperature change to be distributed across multiple smaller temperature differences at each exchange stage, preventing excessive temperature gradients and mechanical stresses while maintaining a compact overall structure.
2Volume of moving object
If the dimensions of the heat exchanger are reduced, then the heat exchanger can be arranged in the reactor building, but the cooling performance may be insufficient to reach the acceptable outlet setpoint temperature
Solution Approach 1:
The hot fluid undergoes multiple sequential heat exchange passes (first through fifth passages) with the cold fluid, ensuring continuous and progressive cooling. This multi-stage continuous heat exchange process ensures that the hot fluid reaches the acceptable outlet setpoint temperature despite the compact size of the heat exchanger, as the cooling action is maintained throughout the entire fluid path.
3Reliability
If a backup circuit with a heat exchanger is implemented for emergency cooling, then the secondary circuit can be cooled independently of the tertiary circuit, but the heat exchanger is subject to strict regulations and technical requirements specific to the nuclear power generation industry
Solution Approach 1:
The cold fluid recirculates through the heat exchanger multiple times (first passage through fifth passage), serving itself to cool the hot fluid across multiple stages. This self-service approach enhances reliability by maintaining continuous cooling capability while using a compact design that reduces overall system complexity and regulatory burden compared to larger traditional emergency cooling systems.
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 method effectively cools water vapor in a compact heat exchanger, preventing damage and ensuring reliable operation by stabilizing temperature differences.
Implementation Method 1
the first fluid leaves and enters the heat exchanger several times so as to exchange with itself and with the second fluid, by indirect contact
Implementation Method 2
exchanges with the second fluid by indirect contact
Implementation Method 3
the first fluid during its first pass successively exchanges with the first fluid during its second pass then with the first fluid during its fourth pass while exchanging with the second fluid
Data Source
Figure 1
AI summary
The invention relates to a cooling method using a heat exchanger (1), the method being intended to cool a first fluid by means of a second fluid, in which method the first fluid leaves and enters the heat exchanger (1) repeatedly so as to exchange heat with itself and with the second fluid, by indirect contact.