Nuclear Control Rod Handling Device with Magnetic Coupling

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Solution Overview

Problem

Existing bar handling devices for nuclear reactors suffer from mechanical failures due to sodium aerosol infiltration, causing corrosive effects and mechanical blockages, primarily resulting from the rupture of metal bellows, which leads to increased maintenance times and reduced reliability.

Innovation Solution

The implementation of a static confinement barrier made of non-magnetic material and magnetic coupling devices that transmit mechanical movements without contact, isolating mechanical parts from the sodium environment and eliminating the risk of sodium aerosol-induced wear and blockages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If metal bellows are used to seal the space between the guide sheath and bar control rod, then sodium aerosol protection is provided, but mechanical blockages and wear occur due to sodium infiltration

Engineering Contradiction:
Improvesodium aerosol protectionVSAvoidmechanical blockage risk
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent removes the metal bellows sealing system from the design. Instead of using flexible metal bellows that can rupture and cause sodium infiltration, the invention extracts this sealing component entirely and replaces it with a rigid non-magnetic sealing structure that eliminates the risk of mechanical failure and sodium aerosol contamination of moving parts.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical flexible sealing system (metal bellows) with a non-magnetic rigid sealing structure combined with magnetic coupling for motion transmission. This substitution eliminates the mechanical wear and rupture issues inherent in flexible metal bellows while maintaining the necessary sealing and motion transmission functions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If motorized means are placed in direct contact with sodium environment, then control function is maintained, but corrosive effects and mechanical failures increase

Engineering Contradiction:
Improvecontrol functionVSAvoidcorrosive effects
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent segments the system into two distinct zones: a sodium-exposed zone containing only the essential control rod and guide sheath, and a protected zone containing all motorized means and mechanical transmission components. This segmentation is achieved through a non-magnetic sealing barrier that physically separates the corrosive sodium environment from the sensitive mechanical components, allowing control function to be maintained while eliminating corrosive effects on motors and gears.

Inventive Principle:
Principle #1Segmentation

3Reliability

If magnetic coupling devices are used to transmit movement through the confinement barrier, then contactless transmission is achieved, but device complexity increases

Engineering Contradiction:
Improvecontactless transmissionVSAvoidmagnetic coupling system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a non-magnetic sealing barrier as an intermediary between the sodium environment and the motorized components. Magnetic coupling devices are then used to transmit rotational motion through this barrier without physical contact. While this adds some complexity, it provides contactless transmission that eliminates wear and sodium contamination of moving parts, significantly improving reliability and reducing maintenance requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of repair

If maintenance operations are performed on devices with sodium infiltration, then mechanical parts are blocked, but maintenance time increases

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidmaintenance time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The patent extracts all motorized means and mechanical transmission components from the sodium environment, placing them in a protected zone separated by a non-magnetic sealing barrier. This extraction prevents sodium infiltration and subsequent mechanical blockages, thereby eliminating the need for frequent maintenance and reducing maintenance time while maintaining ease of repair for the protected components.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This solution enhances the reliability of bar handling devices by protecting mechanical components from sodium aerosols, reducing maintenance times, and minimizing the risk of chemical and nuclear contamination during operations.

Implementation Method 1

magnetic coupling devices that transmit mechanical movements without contact, isolating mechanical parts from the sodium environment

Methodology Applied
Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

a static confinement barrier made of non-magnetic material... isolating mechanical parts from the sodium environment

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP3082131B1Device for handling a control rod of a nuclear reactor
Publication Date: 2017.08.23 ONET TECH CN
  • EP3082131B1 patent drawingFigure 1~1A
  • EP3082131B1 patent drawingFigure 1B~2
  • EP3082131B1 patent drawingFigure 3~4B

AI summary

The present invention relates to a handling device (1) for an absorber rod (11) for the control of a nuclear reactor, comprising (a) an upper drive compartment (2) placed on the closing slab (10) of the reactor vessel (13), (b) a rod control rod (3), extending in said upper drive compartment (2) and in a guide sleeve (3a) extending within said vessel, characterized in that it comprises (1) a sealed static containment enclosure (5) made of magnetic material disposed within said upper compartment, (2) a first synchronous magnetic coupling system (6a) for transmitting linear translational motion without mechanical contact, comprising a first external component (6a-1) disposed outside said enclosure (5), and adapted to be moved in vertical translation, and a first internal component (6a-2) disposed within said enclosure (5),attached to said steering rod (3), a magnetic coupling force of said first external component (6a-1) and said first internal component (6a-2) enabling, when the first external component (6a-1) is moved in vertical translation, that said first internal component (6a-2) and the steering rod (3) follow a vertical translational displacement, and (3) said drive compartment (2) comprising first motorized mechanical means for transmitting translational displacements (2a) of said first external component (6a-1) of said first magnetic coupling system (6a).