Double Containment Cooling With Liquid Nitrogen for Reactor Overpressure
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Solution Overview
Problem
Existing integrated nuclear reactors face the risk of accidents due to overheated steam causing abnormal overpressure, which can lead to reactor vessel explosions and radioactive material leakage.
Innovation Solution
A double containment structure using liquid nitrogen is implemented, comprising a reactor vessel surrounded by a first and second containment vessel, with a liquid nitrogen supply system to cool the system efficiently during abnormal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single containment structure is used, then the device complexity is reduced, but the reliability and safety against overpressure accidents deteriorate
Solution Approach 1:
The containment structure is divided into multiple independent containment vessels (first containment vessel, second containment vessel, third containment vessel) instead of using a single containment structure. Each containment vessel provides an additional barrier against overpressure accidents and radioactive material leakage, thereby improving reliability while maintaining manageable complexity through modular design
Solution Approach 2:
The invention introduces a pressurizing region with water vapor that acts as a cushioning medium between the reactor vessel and the first containment vessel. This pre-positioned cushioning layer absorbs abnormal pressure increases before they can reach the containment vessels, preventing structural failure and improving accident prevention capability
2Reliability
If conventional cooling methods are used, then the cooling capability is sufficient, but the cooling efficiency and response time to abnormal conditions deteriorate
Solution Approach 1:
The invention changes the thermal parameters of the containment vessels by introducing water vapor into the pressurizing region and allowing it to contact the inner surfaces of the containment vessels. This phase change from liquid water to water vapor provides rapid heat absorption and cooling, significantly improving cooling efficiency and response time compared to conventional liquid cooling methods
Solution Approach 2:
The invention replaces conventional mechanical cooling systems with a thermal field-based cooling mechanism using water vapor. Instead of using pumps, fans, or other mechanical devices to force cooling, the system utilizes the natural thermal properties of water vapor to cool the containment vessels, improving efficiency and reducing mechanical complexity
3Reliability
If more coolant is used, then the cooling capacity is increased, but the quantity of substance and system complexity increase
Solution Approach 1:
The invention utilizes the phase transition of water from liquid to vapor in the pressurizing region. This phase change enables a small amount of water to absorb large amounts of heat through latent heat of vaporization, providing high cooling capacity without requiring large quantities of coolant. The water vapor acts as an efficient heat sink that can rapidly cool the containment vessels during abnormal conditions
Solution Approach 2:
The water vapor in the pressurizing region serves as an intermediary cooling medium between the reactor vessel and the containment vessels. Instead of directly cooling the containment vessels with liquid coolant, the system uses water vapor as an intermediate heat transfer medium that can efficiently absorb heat from the reactor vessel and transfer it to the containment vessels, improving cooling capacity while minimizing coolant quantity
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 prevents accidents by rapid cooling and containment of radioactive materials, using less coolant and ensuring safe operation during normal and abnormal conditions.
Implementation Method 1
a liquid nitrogen supply unit for supplying liquid nitrogen to the second space
Implementation Method 2
efficiently cool overheated water vapor in a reactor vessel
Implementation Method 3
a recirculation valve located below the pressure release valve and taking the cooling water condensed in the first space back into the reactor vessel
Implementation Method 4
a pressure release valve connecting the pressurizing region with the first space and discharging water vapor in the pressurizing region to the first space
Data Source
AI summary
The present invention relates to an integrated nuclear reactor system including a double containment structure using liquid nitrogen, the nuclear reactor system comprising: a reactor vessel; a reactor core disposed in the reactor vessel; a steam generator disposed in the reactor vessel and located above the reactor core; a first containment vessel surrounding the reactor vessel with a first space interposed therebetween; a second containment vessel surrounding the first containment vessel with a second space interposed therebetween; and a liquid nitrogen supply unit supplying liquid nitrogen into the second space.