Double-Wall Condensation Tank Cooling for Stable Passive Feedwater

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Solution Overview

Problem

Conventional passive auxiliary feedwater systems experience reduced heat exchange efficiency and cooling performance due to rising water temperatures during the condensation process, which can lead to a decrease in condensate water generation during nuclear reactor accidents.

Innovation Solution

A passive condensation tank cooling system with a double-walled structure and a cooling means between the walls, utilizing a refrigerant to absorb heat and maintain water temperature, combined with a circulation system to enhance cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat exchange water is used in the passive condensation tank to condense steam, then the cooling function is achieved, but the water temperature rises during condensation process

Engineering Contradiction:
Improvewater temperatureVSAvoidheat exchange efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The condensation tank is divided into an inner tank and an outer tank with a space between them. The inner tank contains the heat exchange water, while the outer tank contains cooling water. This segmentation allows independent temperature control of the two water bodies, preventing the heat exchange water from overheating while maintaining effective heat exchange.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat exchanger is introduced as an intermediary component between the inner tank and outer tank. The heat exchanger transfers heat from the heat exchange water to the cooling water, enabling efficient heat transfer while keeping the heat exchange water temperature controlled and preventing direct thermal coupling between the two water bodies.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the water temperature in the passive condensation tank rises, then the condensation process can proceed, but the heat exchange efficiency is reduced

Engineering Contradiction:
Improvecondensate water generationVSAvoidheat exchange water temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

By separating the heat exchange water and cooling water into different tanks with a space between them, the system allows the cooling water to continuously remove heat from the heat exchange water, maintaining optimal temperature for high-efficiency condensation and maximizing condensate water generation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling water continuously circulates through the heat exchanger, providing uninterrupted heat removal from the heat exchange water. This continuous cooling action maintains the heat exchange water at optimal temperature, ensuring sustained high heat exchange efficiency and maximum condensate production throughout the condensation process.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If no separate cooling means is provided, then the system simplicity is maintained, but the cooling performance is insufficient during accidents

Engineering Contradiction:
Improvesystem structureVSAvoidcooling performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses a simple double-tank structure with natural convection currents to achieve effective cooling without complex mechanical components. The temperature difference between the inner and outer tanks drives natural water circulation, providing reliable cooling performance during accidents while maintaining relative system simplicity.

Inventive Principle:
Principle #1Segmentation

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 suppresses water temperature rise, maintaining condensation efficiency and improving cooling performance, ensuring continuous operation and extended cooling function during accidents.

Implementation Method 1

a cooling means between the outer wall and inner wall for absorbing heat of the heat-exchange water is interposed

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a condenser arranged to be immersed in the heat-exchange water in the passive condensation tank

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the steam generated in the steam generator 10 by a natural convection manner is condensed in the condenser 20

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

the steam generated in the steam generator 10 by a natural convection manner is condensed

Methodology Applied
Scientific EffectNatural convection: Free Convection

Data Source

PatentEP4187553B1Passive condensation tank cooling system of passive auxiliary feedwater system
Publication Date: 2026.03.04 KOREA HYDRO & NUCLEAR POWER CO LTD
  • EP4187553B1 patent drawingFigure 1~2
  • EP4187553B1 patent drawingFigure 3

AI summary

The present invention relates to a passive condensation tank cooling system of a passive auxiliary feedwater system and, more specifically, to a passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system having a passive condensation tank that includes an inner wall and an outer wall, having a cooling means interposed between the inner wall and the outer wall so that the temperature of heat-exchange water can be prevented from rising during condensation in the passive condensation tank, and thus the cooling performance of the passive auxiliary feedwater system can be improved, and being capable of contributing to the ensuring of a long-term cooling function during an extreme disaster accident. To this end, provided is the passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system comprising: the passive condensation tank having a water storage space in which the heat-exchange water is stored; and the passive auxiliary feedwater system including a condenser submerged in the heat-exchange water of the passive condensation tank, wherein the passive condensation tank includes: the outer wall for forming the outermost wall of the passive condensation tank; and the inner wall spaced from the outer wall to form the water storage space, and the cooling means capable of absorbing heat of the heat-exchange water is interposed between the outer wall and the inner wall.