Carbonate Sacrificial Material for Corium Cooling
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Solution Overview
Problem
Existing nuclear reactors face challenges in effectively cooling and immobilizing molten corium during accidents, leading to potential radioactive releases and hydrogen gas formation, as they rely on water cooling and cannot easily incorporate sacrificial materials to manage severe accident scenarios.
Innovation Solution
A carbonate-based granular material system is introduced for injection into the reactor containment, which undergoes endothermic decomposition to rapidly cool and solidify molten corium, generating an inert gas and creating porosity to facilitate further cooling, while minimizing hydrogen gas release and maximizing radionuclide retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water cooling is used to cool molten corium, then cooling effect is achieved, but hydrogen gas release increases and corium immobilization is insufficient
Solution Approach 1:
The patent changes the material parameter from water to carbonate-based sacrificial material. The carbonate material undergoes endothermic decomposition at high temperatures, absorbing heat from corium while producing CO2 gas that inhibits hydrogen formation. This parameter change resolves the contradiction by providing cooling without the harmful hydrogen gas release associated with water cooling.
Solution Approach 2:
The patent utilizes the phase transition of carbonate material from solid to gas (CO2 decomposition) during the cooling process. The endothermic decomposition reaction absorbs thermal energy from corium, effectively cooling it, while the generated CO2 gas creates a protective atmosphere that prevents hydrogen gas release. This phase transition mechanism simultaneously achieves cooling and eliminates the harmful effect.
2Reliability
If sacrificial material is added to contain corium, then corium immobilization improves, but device complexity increases
Solution Approach 1:
The patent extracts the sacrificial material from the reactor core area and stores it in a separate containment vessel. The material is delivered to the corium pool location only when needed during an accident scenario. This extraction approach simplifies the overall system by separating the storage function from the reaction zone, reducing operational complexity while maintaining containment reliability.
Solution Approach 2:
The patent introduces a fluid delivery system as an intermediary mechanism to transport the carbonate-based sacrificial material from the storage vessel to the corium pool. This intermediary delivery system simplifies the interface between the stored material and the accident scenario, allowing controlled material introduction without direct complex interaction mechanisms in the reactor core.
3Reliability
If carbonate-based material is injected into containment, then cooling and immobilization effectiveness increases, but manufacturing and storage requirements become more complex
Solution Approach 1:
The patent optimizes the particle size parameter of the carbonate-based sacrificial material to enhance its effectiveness. By controlling the material to have specific particle size distributions, the system achieves improved cooling efficiency and corium immobilization while maintaining ease of handling and storage. This parameter optimization resolves the contradiction between effectiveness and manufacturability.
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 carbonate-based material effectively cools and immobilizes corium, reduces hydrogen gas generation, and enhances radionuclide retention, preventing radioactive releases and providing a barrier to corium movement, thus enhancing containment safety during nuclear accidents.
Implementation Method 1
A carbonate-based granular material system is introduced for injection into the reactor containment, which undergoes endothermic decomposition to rapidly cool and solidify molten corium
Implementation Method 2
undergoes endothermic decomposition to rapidly cool and solidify molten corium, generating an inert gas and creating porosity to facilitate further cooling
Implementation Method 3
The carbonate-based material effectively cools and immobilizes corium, reduces hydrogen gas generation, and enhances radionuclide retention, preventing radioactive releases and providing a barrier to corium movement
Data Source
AI summary
Systems and methods for injecting a carbonate-based sacrificial material into a nuclear reactor containment for containment of molten corium in severe nuclear reactor accidents are disclosed. Molten corium can be quickly cooled and solidified by the endothermic decomposition of the sacrificial material.