Nuclear Reactor Corium Cooling System with Membrane Pressure Control
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Solution Overview
Problem
Current corium localizing and cooling systems in nuclear reactors face issues such as destruction due to rapid gas pressure increase and loss of leak-tight joints during reactor pressure vessel melt-through, leading to malfunction and potential containment breach.
Innovation Solution
The system incorporates a drum with strengthening ribs and a concave membrane with heat resistance elements, along with thermal protection consisting of external and internal shells, to manage thermal and mechanical loads, provide independent expansions, and maintain leak-tightness during earthquakes and impact, while ensuring efficient cooling and pressure management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the corium localizing and cooling system uses a layered vessel with cantilever truss and filler cassettes, then the system can localize and cool corium, but the system may be destroyed by rapid gas pressure increase during reactor pressure vessel melt-through
Solution Approach 1:
The system is divided into segmented components: layered vessel, cantilever truss, filler cassettes, and guide plate. This segmentation allows each component to be optimized independently and facilitates controlled displacement during severe accidents, preventing catastrophic failure of the entire system due to gas pressure increases
Solution Approach 2:
The cantilever truss and layered vessel are designed to allow independent displacement during heating, impact, or earthquake actions. This dynamic capability enables the system to accommodate thermal expansion and mechanical stresses without destroying the leak-tight joint, thereby maintaining system integrity under varying operational conditions
2Stability of the object's composition
If the cantilever truss and layered vessel are rigidly connected to maintain leak-tight joint, then the joint remains sealed, but the system cannot accommodate independent displacement during heating or earthquake actions
Solution Approach 1:
The connection between cantilever truss and layered vessel is designed to allow controlled independent displacement while maintaining leak-tight integrity. This dynamic design enables the system to adapt to thermal expansion, impact, and earthquake actions without compromising the seal, resolving the contradiction between rigidity and adaptability
3Temperature
If water is supplied to cool the layered vessel during corium intake, then heat removal efficiency increases, but the layered vessel may flood and lose structural integrity
Solution Approach 1:
The system replaces active mechanical cooling control with a passive membrane-based pressure control mechanism. The membrane automatically responds to pressure changes caused by water supply, preventing flooding while maintaining effective cooling through passive pressure equalization rather than active mechanical control
4Reliability
If a membrane is used to control water supply to corium, then flooding is prevented, but the membrane may be damaged by thermal and mechanical loads
Solution Approach 1:
The membrane is pre-positioned and pre-tensioned to anticipate and withstand thermal and mechanical loads before they occur. This beforehand cushioning allows the membrane to resist damage from subsequent thermal expansion and pressure changes, maintaining water supply control reliability under severe accident conditions
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
Enhances the reliability and efficiency of corium localization and cooling by preventing flooding, maintaining structural integrity, and ensuring effective heat removal, thereby protecting the reactor containment and environment from severe accidents.
Implementation Method 1
input for cooling the external surface of the layered vessel
Implementation Method 2
efficient cooling... ensuring effective heat removal
Implementation Method 3
flange (5) thereof is provided with thermal protection (6)... thermal protection consisting of external and internal shells
Implementation Method 4
gas pressure is quickly increased in these spaces following which the destruction of the corium localizing and cooling system may take place
Data Source
AI summary
The invention relates to the field of nuclear energy, in particular, to systems that ensure the safety of nuclear power plants (NPP), and can be used in severe accidents that lead to reactor pressure vessel and its containment destruction.The technical result of the claimed invention consists in increasing the reliability of the corium localizing and cooling system of a nuclear reactor, increase of heat removal efficiency from corium of a nuclear reactor.The technical result is achieved by using the membraned, drum and thermal protection installed in the area between the layered vessel and cantilever truss in the corium localizing and cooling system of a nuclear reactor.