Segmented Coolant Tank for Passive Containment Cooling
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Solution Overview
Problem
In nuclear reactor buildings, passive cooling systems face challenges in maintaining effective heat removal during design basis and severe accidents, leading to re-pressurization and reheating due to inefficiencies in cooling water temperature management.
Innovation Solution
A nuclear reactor building passive cooling system is designed with a storage tank divided into two compartments, a first and a second storage tank, where a unidirectional valve allows cooling water from the second tank to flow into the first when the water level drops, and a second heat exchanger extends outside to cool the water, maintaining heat removal performance and preventing re-pressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling water is used repeatedly for heat exchange, then thermal energy is removed initially, but the cooling water temperature rises and thermal energy cannot be completely removed, causing temperature and pressure to rise again
Solution Approach 1:
The storage tank is divided into a first storage tank and a second storage tank by a partition part. The first storage tank stores cooling water at a lower level, while the second storage tank stores cooling water at a higher level. This segmentation allows for stratified temperature management where cooler water can be maintained in the second tank and introduced to the heat exchanger as needed, preventing the entire cooling water volume from heating up and maintaining continuous heat removal effectiveness.
Solution Approach 2:
The unidirectional valve is pre-configured to allow cooling water to flow from the second storage tank to the first storage tank when the water level in the first storage tank is reduced. This preliminary arrangement ensures that fresh or cooler cooling water is automatically supplied to maintain heat exchange effectiveness without requiring active intervention, preventing temperature and pressure rise before they occur.
2Device complexity
If a simple single-chamber storage tank is used, then the system is simple, but cooling water temperature rises due to repeated heat exchange and heat removal becomes ineffective
Solution Approach 1:
The storage tank is segmented into two distinct chambers (first and second storage tanks) with different water levels. This segmentation enables differentiated temperature management and continuous supply of effective cooling water to the heat exchanger, maintaining passive cooling performance without requiring complex external control systems.
Solution Approach 2:
The unidirectional valve acts as an intermediary mechanism between the first and second storage tanks. It automatically regulates water flow from the second storage tank to the first storage tank based on water level conditions, ensuring continuous supply of cooling water to maintain heat removal effectiveness without complex control systems.
3Ease of operation
If cooling water temperature is not managed, then the system operates passively, but temperature and pressure in the nuclear reactor building rise again after initial cooling
Solution Approach 1:
The storage tank is segmented into two distinct chambers (first and second storage tanks) with different water levels. This segmentation enables differentiated temperature management and continuous supply of effective cooling water to the heat exchanger, maintaining passive cooling performance without requiring complex control systems.
Solution Approach 2:
The unidirectional valve is pre-configured to allow cooling water to flow from the second storage tank to the first storage tank when the water level in the first storage tank is reduced. This preliminary arrangement ensures that fresh or cooler cooling water is automatically supplied to maintain heat exchange effectiveness without requiring active intervention, preventing temperature and pressure rise before they occur.
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 configuration stabilizes the cooling system's performance, continuously reduces pressure and temperature, and prevents secondary accidents like nuclear reactor building destruction by ensuring consistent heat removal and preventing re-pressurization and reheating.
Implementation Method 1
a first heat exchanger extending from the storage tank to the nuclear reactor building and cooling the nuclear reactor building on the basis of the cooling water
Implementation Method 2
a unidirectional valve provided on the partition part and allowing the cooling water of the second storage tank to flow into the first storage tank when a water level of the first storage tank is reduced
Implementation Method 3
a second heat exchanger extending from the first storage tank to outside of the storage tank to cool the cooling water of the first storage tank
Implementation Method 4
an air inlet part provided on an outer surface of the storage tank to induce air to flow into the second heat exchanger
Data Source
AI summary
In order to provide a coolant tank for preventing a containment from being recompressed and reheated during the cooling of the containment upon occurrence of a design basis accident and a severe accident and a passive containment cooling system comprising the same, the present invention comprises: a storage tank for storing a coolant; a division part which is arranged within the storage tank and divides the inside of the storage tank into a first storage tank and a second storage tank to separate the coolant; a first heat exchanger which is extended from the storage tank to the containment and cools the containment on the basis of the coolant; and a unidirectional valve which is provided on the division part and allows the coolant of the second storage tank to be introduced into the first storage tank when the water level of the first storage tank is reduced.