Nuclear Sample Hood With Screw-Nut Mechanism and Bellows Sealing

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Solution Overview

Problem

Existing hoods fail to reliably handle and contain slender objects, such as sample holder tubes in nuclear research reactors, due to limitations in sealing and precise control of gripping mechanisms, especially in confined and underwater environments, leading to inefficiencies and rapid wear of sealing components.

Innovation Solution

A containment and handling hood with a motorized screw-nut mechanism and manual control systems allows precise translation and rotation of gripping members, incorporating metal bellows for sealing, enabling reliable and high-rate handling of elongated objects within a compact, sealed environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a hood is designed to handle and contain slender objects like sample holder tubes in nuclear research reactors, then the handling capability is improved, but the sealing reliability deteriorates due to the confined and underwater environment

Engineering Contradiction:
Improvehandling capabilityVSAvoidsealing reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The hood is divided into multiple sealed compartments including a manipulation compartment and a containment compartment, each with independent sealing mechanisms. This segmentation allows the hood to handle slender objects while maintaining reliable sealing in each separate zone, addressing the contradiction between handling capability and sealing reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A transfer mechanism acts as an intermediary between the manipulation compartment and containment compartment, enabling the transfer of sample holder tubes while maintaining sealing integrity. This intermediary system allows handling operations without compromising the sealed environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a gripping mechanism is designed for precise control of slender objects, then the control precision is improved, but the device complexity increases

Engineering Contradiction:
Improvecontrol precisionVSAvoidgripping mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The gripping mechanism replaces complex mechanical control systems with a combination of magnetic attraction and gravitational force. The magnetic system provides precise control for positioning and gripping slender objects, while gravity assists in the release process, reducing overall mechanism complexity while maintaining high control precision.

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

Solution Approach 2:

The gripping mechanism utilizes changes in magnetic field parameters to control the gripping and release of objects. By adjusting magnetic field strength and distribution, the system achieves precise control without requiring complex mechanical adjustments, thereby reducing device complexity.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If sealing components are designed for use in underwater environments, then the environmental adaptability is improved, but the component lifespan deteriorates due to rapid wear

Engineering Contradiction:
Improveenvironmental adaptabilityVSAvoidcomponent lifespan
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

Sealing components are constructed using composite materials that combine the advantages of different materials to resist wear in underwater environments. These composite materials maintain sealing effectiveness while significantly extending component lifespan by resisting the harsh underwater conditions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The design incorporates protective features that cushion and distribute mechanical stresses on sealing components before they can cause wear. This beforehand protection reduces the impact of repeated operations on sealing surfaces, extending component lifespan while maintaining environmental adaptability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If the hood is designed for high-rate handling of objects, then the productivity is improved, but the sealing integrity deteriorates due to frequent operations

Engineering Contradiction:
Improvehandling rateVSAvoidsealing integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The hood incorporates pre-positioned sample holder tubes in the containment compartment before irradiation operations begin. This preliminary arrangement allows for rapid exchange operations without requiring frequent opening and closing of sealed compartments, thereby maintaining sealing integrity while enabling high-rate handling.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The design enables continuous handling operations through a system where multiple sample holder tubes can be pre-positioned and exchanged in sequence without breaking the sealed environment. This continuity allows high productivity while maintaining constant sealing integrity throughout the operation.

Inventive Principle:
Principle #20Continuity of useful action

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 hood ensures secure and efficient handling and containment of slender objects with precise control over gripping and locking mechanisms, maintaining sealing integrity and extending the lifespan of sealing components, even in challenging environments like nuclear reactor pools.

Implementation Method 1

a screw-nut mechanism consisting of an endless screw guided in rotation about the axis X1, X2, and of a nut around the screw and to which the gripping member is secured, the mechanism being adapted to guide in translation of the latter in the internal enclosure

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

incorporating metal bellows for sealing, enabling reliable and high-rate handling of elongated objects within a compact, sealed environment

Methodology Applied
Scientific EffectMetal bellows sealing:

Data Source

PatentEP2789550B1Handling and containment hood, use for handling sample-holders of nuclear materials, such as nuclear fuels
Publication Date: 2016.07.06 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2789550B1 patent drawingFigure 1~3
  • EP2789550B1 patent drawingFigure 4A~4E
  • EP2789550B1 patent drawingFigure 4F~4J

AI summary

The present invention concerns a hood for handling and confinement of at least two objects of slender shape, including an external enclosure and internal enclosures inside the external enclosure and at least one motor fixed above an internal enclosure and inside a barrel, the motor(s) being adapted to rotate the screw of the screw-nut mechanism of each internal enclosure and therefore the nut over a stroke A, and first and second mechanical control means, arranged in part above the cover of the external enclosure, respectively for manually guiding the internal enclosures in translation over a stroke A0 and manually pivoting the barrel in order to bring a holding member of one of the internal enclosures opposite the opening in the bottom of the external enclosure. Application to the handling and confinement of nuclear material sample holders.