Polyimide Noble Gas Filter for Hydrolysis-Resistant Venting
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Solution Overview
Problem
Existing nuclear reactor containment vessel vent systems face challenges in maintaining durability and effectiveness in removing radioactive noble gases due to hydrolysis of polyimide films used in membrane filters when exposed to high-temperature water vapor during accidents.
Innovation Solution
A polyimide film with a structural unit represented by a specific general formula is used, featuring a bent configuration of imide and aromatic rings to enhance durability by minimizing hydrolysis, ensuring effective removal of radioactive noble gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyimide film is used as a membrane filter to remove radioactive noble gases, then the filter achieves excellent heat resistance and selective permeability, but the filter suffers from hydrolysis reaction by water molecules leading to reduced durability
Solution Approach 1:
The patent modifies the chemical structure of polyimide by changing parameters such as introducing fluorine atoms into the polymer chain and adjusting the imide ring structure. These structural parameter changes reduce the film's susceptibility to hydrolysis while maintaining its heat resistance and selective permeability properties, thereby resolving the contradiction between durability and hydrolysis resistance.
Solution Approach 2:
The patent creates a composite structure by combining polyimide with fluorine-containing groups and other functional moieties. This composite approach enhances the film's resistance to hydrolysis and improves overall durability while preserving the essential membrane function of selectively removing radioactive noble gases.
2Reliability
If the polyimide film structure is modified to reduce hydrolysis, then the filter durability improves, but the membrane area and permeability characteristics must be optimized to maintain effective noble gas removal
Solution Approach 1:
The patent systematically adjusts parameters including the degree of fluorine substitution, imide ring configuration, and polymer chain arrangement to simultaneously achieve enhanced durability and maintained noble gas removal efficiency. By optimizing these parameters, the film resists hydrolysis better while preserving the necessary permeability for effective operation.
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 solution provides a filter unit and vent system with improved durability and efficiency in removing radioactive noble gases, preventing pressurization and minimizing leakage of radioactive materials, even under high-temperature conditions.
Implementation Method 1
a polyimide film having a dense structure and having a lower noble gas permeability than water vapor permeability
Implementation Method 2
a membrane filter that is permeable to water vapor but impermeable to noble gases
Implementation Method 3
there is a possibility that hydrolysis reaction by water molecules is reversibly induced
Implementation Method 4
a first steric structure of the one or more first aromatic rings, a second steric structure of the first imide ring, and a third steric structure of the second imide ring are not disposed on a plane and make a bent configuration
Data Source
AI summary
A radioactive noble gas removal filter, a filter unit, and a nuclear reactor containment vessel vent system with improved durability are provided. The radioactive noble gas removal filter according to the present invention includes a polyimide film including a structural unit represented by general formula (1).