Rotating Eddy Current Weld Inspection for Tubular Elements

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Solution Overview

Problem

Existing methods for inspecting welds in nuclear reactor pipes are lengthy, tedious, involve handling radioactive sources, and do not provide real-time results, posing risks and operational challenges.

Innovation Solution

A control device for welds in hollow tubular elements using an eddy current sensor system with rotational and longitudinal drives, enabling precise, non-destructive, and rapid inspection, eliminating the need for radioactive sources and chemical handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radiographic inspection device with radioactive source is used, then weld inspection capability is achieved, but inspection time is lengthy and real-time results are not provided

Engineering Contradiction:
Improveweld inspection capabilityVSAvoidinspection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the radiographic inspection system (using radioactive sources and photographic film) with an electromagnetic inspection system using eddy current sensors. This substitution enables real-time signal processing and immediate weld defect detection, eliminating the lengthy chemical development process and providing real-time inspection results.

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

Solution Approach 2:

The invention changes the inspection parameters by using electromagnetic induction principles instead of radiation. The eddy current sensors generate alternating magnetic fields that induce currents in the conductive weld material, and changes in these currents reveal defects. This parameter change from radiographic to electromagnetic methods enables real-time feedback.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If radiographic inspection with radioactive source is used, then weld inspection is performed, but handling risks and operational restrictions increase

Engineering Contradiction:
Improveweld inspection capabilityVSAvoidradiation handling risks
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes the hazardous radioactive source with a non-ionizing electromagnetic field generated by eddy current sensors. This replacement eliminates all radiation safety concerns, removes the need for specialized radiation training, and allows unrestricted site activities to occur concurrently during inspection.

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

Solution Approach 2:

The invention converts the potentially harmful electromagnetic radiation into a beneficial non-ionizing electromagnetic field for inspection purposes. The eddy current system uses low-frequency electromagnetic fields that are safe for operators and do not pose radiation hazards, while still providing effective weld inspection capability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If eddy current sensor block is used, then inspection speed is improved, but device complexity increases due to rotational and longitudinal drive mechanisms

Engineering Contradiction:
Improveinspection speedVSAvoiddrive mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent employs a single rotating support structure that simultaneously performs multiple functions: it positions the eddy current sensor block along the longitudinal axis of the weld, rotates the sensor around the tubular element, and controls the inspection sequence. This multi-functional design achieves comprehensive weld inspection without requiring separate complex drive mechanisms for each motion.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the longitudinal positioning function and rotational positioning function into a single integrated support mechanism. The support structure combines linear translation capability with rotational capability, allowing the sensor block to be positioned both along the weld length and around the tubular element using one coordinated system, thereby reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

Facilitates shorter inspection times with real-time results, reducing risks and allowing concurrent site activities, while ensuring accurate and reliable weld assessments.

Implementation Method 1

at least one eddy current sensor block (24) linked to the moving part (19)

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 2

The support (29) comprises at least one eddy current sensor block (24) linked to the moving part (19)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3956657B1Device for inspecting a weld of a hollow longitudinal tubular element
Publication Date: 2026.01.07 FRAMATOME SA
  • EP3956657B1 patent drawingFigure 1
  • EP3956657B1 patent drawingFigure 2
  • EP3956657B1 patent drawingFigure 3

AI summary

The invention concerns a device (10) for inspecting a weld of a hollow longitudinal tubular element, comprising: - a frame (12), - a system (14) for hooking and locking said frame on the tubular element, - a movable member (19) connected to the frame (12) and rotatable with respect to the frame (12) about the tubular element, - a device (20) for rotating the movable member (19) with respect to the chassis (12), - a support (29) including at least one sensor block (24) for sensing Foucault currents connected to the movable member (19), the support (29) being movable in longitudinal translation with respect to the movable member (19), - a device (26) for driving the support (29) in longitudinal translation.