Nuclear Reactor Double Containment Using Liquid Nitrogen for Steam Cooling
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Solution Overview
Problem
Existing integrated nuclear reactors face challenges in efficiently cooling overheated steam to prevent accidents and leakage of radioactive materials during abnormal transient states, as conventional methods may not adequately manage pressure and contain potential explosions.
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 second space, allowing for rapid condensation and circulation of water vapor, thereby preventing overheating and containing radioactive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling methods are used to cool overheated steam, then the reactor temperature can be reduced, but the cooling efficiency is insufficient and cannot prevent accidents during abnormal transient states
Solution Approach 1:
The patent changes the cooling medium from conventional water-based cooling to liquid nitrogen cooling. Liquid nitrogen has superior thermal properties including higher heat transfer coefficient and lower freezing point, enabling it to efficiently cool overheated steam and prevent accidents during abnormal transient states. This parameter change fundamentally improves both cooling efficiency and reliability.
Solution Approach 2:
The patent utilizes the phase transition of liquid nitrogen to gaseous nitrogen during the cooling process. When liquid nitrogen contacts overheated steam, it rapidly vaporizes, absorbing large amounts of heat in the process. This phase transition mechanism provides extremely efficient cooling capability that can quickly reduce steam temperature and prevent thermal runaway accidents.
2Reliability
If a single containment structure is used, then the device complexity is reduced, but the containment capability against radioactive material leakage is insufficient
Solution Approach 1:
The patent divides the containment structure into multiple independent containment vessels (first containment vessel, second containment vessel, third containment vessel). Each vessel provides an additional barrier against radioactive material leakage. This segmentation creates a multi-layer defense system where if one containment layer is breached, other layers remain intact to prevent radioactive release.
Solution Approach 2:
The patent implements a nested containment structure where the first containment vessel is positioned inside the second containment vessel, which is in turn positioned inside the third containment vessel. This nested arrangement creates concentric containment barriers, maximizing the containment capability while optimizing space utilization. Each nested layer adds an independent barrier against radioactive material leakage.
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 cools the reactor and prevents accidents by using liquid nitrogen as a coolant, maintaining stability and safety through rapid condensation and circulation, while also containing radioactive materials within the double containment structure.
Implementation Method 1
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 pressure release valve connecting the pressurizing region with the first space and discharging water vapor in the pressurizing region to the first space
Implementation Method 4
a recirculation valve located below the pressure release valve and taking the cooling water condensed in the first space back into the reactor vessel
Data Source
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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.