Nuclear Reactor Electrical Feedthrough Design
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Solution Overview
Problem
In nuclear reactors, especially integral pressurized water reactors, the challenge lies in routing electrical and instrumentation cables from the reactor core to the outside while minimizing vessel penetrations, as existing methods like thimble tubes and conduit designs can lead to leaks and increased risk during Loss of Coolant Accidents, and internal control rod drive mechanisms require numerous electrical penetrations, burdening the seal table.
Innovation Solution
The development of an electrical feedthrough system that includes a sealed cylinder with a flange and end plate, allowing electrical conductors to pass through while maintaining pressure integrity, with an outside connector accessible from outside the vessel, reducing the need for multiple penetrations and minimizing the risk of leaks by using a pressure retaining flange and hermetically sealed connectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thimble tubes and conduits are used to route cables from the core to outside, then cable routing is enabled, but the risk of leaks increases and reliability deteriorates
Solution Approach 1:
The patent combines multiple functions (electrical connection, sealing, and cable routing) into a single integrated feedthrough assembly. The feedthrough integrates the electrical connector, sealing flange, and cable conduit into one unified component that penetrates the pressure vessel wall, eliminating the need for separate thimble tubes and conduit systems while maintaining hermetic sealing.
Solution Approach 2:
The feedthrough assembly acts as an intermediary component between the pressurized reactor interior and the atmospheric exterior. It provides a controlled transition zone with hermetic sealing that allows electrical conductors to pass through while preventing coolant leakage, thereby mediating the conflict between cable routing needs and leak prevention.
2Extent of automation
If multiple electrical penetrations are made for internal control rod drive mechanisms, then electrical power and control are enabled, but the number of penetrations increases and reliability deteriorates
Solution Approach 1:
The feedthrough assembly is designed as a universal multi-functional component that can accommodate multiple electrical conductors and cables within a single penetration point. The internal connector with multiple contact points allows power, control, and instrumentation signals to be transmitted through one integrated feedthrough, serving multiple functions that would otherwise require separate penetrations.
3Reliability
If vessel penetrations are minimized, then leak risk is reduced, but cable routing flexibility is constrained
Solution Approach 1:
The feedthrough assembly segments the cable routing function from the penetration function. It provides a dedicated sealed pathway within the feedthrough body that can accommodate multiple cables and conductors of different types and sizes, allowing flexible cable routing configurations while maintaining a single fixed penetration point in the pressure vessel wall.
Data Source
AI summary
A nuclear reactor includes a nuclear reactor core comprising fissile material and a pressure vessel containing the nuclear reactor immersed in primary coolant water at an operating pressure. The pressure vessel has a vessel penetration passing through a wall of the pressure vessel. An electrical feedthrough seals the vessel penetration and has an outside electrical connector mounted at the pressure vessel. The outside electrical connector is at atmospheric pressure. The electrical feedthrough may include a flange disposed inside the pressure vessel and sealing against an inside surface of the wall of the pressure vessel. The outside electrical connector of the electrical feedthrough may be inset into the wall of the pressure vessel.