Water-Air Passive Cooling System for Extended Nuclear Reactor Safety
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Solution Overview
Problem
General passive auxiliary feed water cooling systems for nuclear reactors face limitations in extending cooling water exhaustion time, requiring larger tank volumes and increased structural support, and are vulnerable to operator errors and power failures, with existing systems only having an 8-hour cooling ability that needs to be extended to 72 hours or more.
Innovation Solution
A water-air combined passive feed water cooling system that uses an air cooling heat exchanger to condense steam from the cooling tank and recirculate it back into the tank, along with a cooling air blower for enhanced air flow, allowing for continuous cooling without the need for increased tank volume or complex control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the volume of the cooling tank is increased to extend cooling time from 8 hours to 72 hours or more, then the cooling time is improved, but the device complexity and structural support requirements worsen
Solution Approach 1:
The patent utilizes phase transition of water (liquid to vapor and back) to extend cooling time. Steam generated from the cooling tank is discharged into the air, and condensed water is collected and reused, creating a cyclic process that extends cooling duration without requiring proportionally larger tank volume or enhanced structural support.
2Duration of action of moving object
If the volume of the cooling tank is increased to extend cooling time, then the cooling time is improved, but the weight and structural strength requirements worsen
Solution Approach 1:
The patent utilizes phase transition of water (liquid to vapor and back) to extend cooling time. Steam generated from the cooling tank is discharged into the air, and condensed water is collected and reused, creating a cyclic process that extends cooling duration without requiring proportionally larger tank volume or enhanced structural support.
3Quantity of substance
If an auxiliary feed water pump is used to maintain cooling water level, then the cooling water level is maintained, but the reliability worsens due to operator errors, power failure, or pump malfunction
Solution Approach 1:
The patent implements a self-service system where the cooling tank automatically maintains its water level through natural circulation. Steam generated from the cooling tank is discharged into the air, and condensed water is collected and automatically returned to the tank, eliminating the need for external pumps or operator intervention and thereby improving system reliability.
4Ease of operation
If a passive auxiliary feed water cooling system is used, then the system operates without electricity, but the cooling time is limited to 8 hours without extended structural design
Solution Approach 1:
The patent utilizes phase transition of water (liquid to vapor and back) to extend cooling time. Steam generated from the cooling tank is discharged into the air, and condensed water is collected and reused, creating a cyclic process that extends cooling duration without requiring proportionally larger tank volume or enhanced structural support.
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 solution extends the cooling water exhaustion time beyond 72 hours without increasing the tank volume or structural support, reduces the risk of system failure due to power outages, and maintains cooling efficiency through natural and forced air circulation, providing a cost-effective and reliable cooling solution for nuclear reactors.
Implementation Method 1
a water cooling heat exchanger connected to the inside of a containment building to cool down heat of a steam generator using a water cooling method
Implementation Method 2
when cooling water in a heat exchange cooling tank (PCCT: Passive Containment Cooling Tank) 1 located outside a reactor containment building boils, generated steam 2 is discharged into the air
Implementation Method 3
an air cooling heat exchanger connected to the evaporative steam pipe and cooling down and liquefying the steam flowing into the evaporative steam pipe
Implementation Method 4
a cooling air blower installed inside the air induction duct and forcibly generating an air flow
Data Source
AI summary
Disclosed herein is a water-air combined passive feed water cooling apparatus including a water cooling heat exchanger connected to the inside of a containment building to cool down heat of a steam generator using a water cooling method, a cooling tank including the water cooling heat exchanger therein and storing cooling water condensing main steam generated by the steam generator, an evaporative steam pipe connected to the cooling tank, the evaporative steam pipe, into which steam of the cooling water generated by the water cooling heat exchanger in the cooling tank flows, an air cooling heat exchanger connected to the evaporative steam pipe and cooling down and liquefying the steam flowing into the evaporative steam pipe, and a condensed water collecting pipe for refilling the cooling tank with the steam liquefied by the air cooling heat exchanger.