Nuclear Electrical Penetration With Segmented Insulating Seals
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Solution Overview
Problem
Existing electrical penetrations in nuclear power plants lack the necessary insulation performance and cable replaceability, and fail to maintain device functionality during severe accidents.
Innovation Solution
An electrical penetration design featuring a tubular sleeve with insulating seal members and wiring covered by an insulator made of the same material as the outer seal, using materials like tetrafluoroethylene and ethylene-propylene-diene rubber, ensuring continuous functionality during severe accidents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrical penetration designs are used, then cable replaceability is achieved, but insulation performance is insufficient for severe accident conditions
Solution Approach 1:
The patent employs composite material construction by combining the insulator made of PTFE (polytetrafluoroethylene) with the outer seal member made of EPR (ethylene-propylene-diene rubber) material. This composite structure integrates the high insulation performance of PTFE with the sealing capabilities of EPR, achieving both excellent insulation characteristics and airtightness required for severe accident conditions while maintaining a manageable structural complexity through the coordinated design of these two specialized materials.
2Reliability
If insulation performance is enhanced for severe accident conditions, then device functionality is maintained, but manufacturing complexity increases
Solution Approach 1:
The patent divides the electrical penetration structure into distinct functional segments: the insulator made of PTFE material and the outer seal member made of EPR material. This segmentation allows each component to be manufactured separately using material-appropriate processes, then assembled together. The insulator can be produced through PTFE extrusion or molding, while the outer seal member can be manufactured via EPR molding, enabling specialized manufacturing for each material's properties before final assembly, thus managing overall manufacturing complexity.
Solution Approach 2:
The patent applies local quality by assigning different materials to different functional zones: PTFE material is used specifically for the insulator where high insulation performance is critical, while EPR material is used for the outer seal member where airtightness and sealing are paramount. This localized material selection optimizes each region's performance for its specific function while maintaining overall manufacturability through standardized assembly processes.
3Reliability
If airtightness is improved using specialized seal materials, then insulation resistance is maintained, but material selection constraints increase
Solution Approach 1:
The patent utilizes composite material construction by combining PTFE material for the insulator with EPR material for the outer seal member. This composite approach achieves both excellent airtightness through the EPR seal member's elastic sealing properties and high insulation resistance through the PTFE insulator's dielectric characteristics. The specific material selection is constrained by the need to achieve these dual performance requirements, but the composite structure optimizes within these constraints by leveraging the complementary strengths of each material.
Data Source
AI summary
To provide an electrical penetration capable of being used in nuclear power plants which are designed assuming operation under conditions of the severe accident. An electrical penetration includes: a tubular sleeve member 10; two or more insulating seal members 20A and 20B arranged inside the sleeve member 10 so as to be spaced from each other; wiring members 60, 60 disposed along the longitudinal direction of the sleeve member 10 so as to extend across two insulating seal members of the two or more insulating seal members 20A and 20B; and outer seal members provided inside the sleeve member 10 and at the outermost portions of the two insulating seal members 20A and 20B. The wiring members 60, 60 are each covered with an insulator made of the same material as those of the outer seal members 21A and 21B.