Self-Service Repair Device for Nuclear Nozzle Inner Periphery

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Solution Overview

Problem

Existing repair devices for nuclear reactor containment welded parts face inefficiencies in cutting wide areas, requiring tool replacement and manual assistance for installation, which hinders simultaneous repair operations across multiple nozzles.

Innovation Solution

A repair device with a cutting mechanism featuring a turn table and slide shaft, where cutting tools helically turn to cut the pipe's inner periphery, and a cutting-tool switching unit with a ratchet mechanism and fluid pressure system allows for seamless tool replacement and continuous operation within the pipe, enabling self-standing installation and streamlined repairs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cutting tools are manually replaced during wide area cutting operations, then the cutting operation can be continued, but manual assistance is required which hinders simultaneous repair operations across multiple nozzles

Engineering Contradiction:
Improvecutting operation continuityVSAvoidmanual assistance requirement
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The cutting mechanism is equipped with an automatic tool replacement system that can swap cutting tools without manual assistance. The system includes a tool magazine storing multiple cutting tools and an automatic changing mechanism that selects and installs the appropriate tool based on the cutting progress, enabling the device to service itself during operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Multiple cutting tools are pre-loaded into the tool magazine before the cutting operation begins. The system is prepared in advance with all necessary tools, so when a tool needs replacement during cutting, it can be immediately swapped without waiting for manual intervention, maintaining operational continuity.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the repair device requires manual assistance for tool installation, then tools can be replaced, but simultaneous repair operations across multiple nozzles cannot be performed

Engineering Contradiction:
Improvesimultaneous repair capabilityVSAvoidinstallation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The automatic tool replacement system enables the device to operate independently without manual assistance, allowing multiple repair devices to be deployed simultaneously across different nozzles. Each device manages its own tool inventory and replacement needs autonomously.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The tool replacement function is segmented into independent modular components including a tool magazine, selection mechanism, and installation apparatus. This modular design reduces overall system complexity while enabling automatic operation.

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If cutting tools are replaced during wide area cutting, then the entire area can be covered, but operation time increases due to tool replacement interruptions

Engineering Contradiction:
Improvecutting area coverageVSAvoidtool replacement time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The automatic tool replacement system maintains continuous cutting action by pre-positioning multiple tools and executing rapid automated swaps. The cutting operation never stops during tool replacement, eliminating idle time and maintaining productive action throughout the entire cutting process.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

Multiple cutting tools are pre-loaded into the magazine before operation begins. When a tool is depleted, the system immediately accesses the pre-positioned next tool and swaps it in seconds, rather than stopping to manually retrieve and install a new tool, significantly reducing replacement time.

Inventive Principle:
Principle #10Preliminary 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 device efficiently cuts wide areas within the pipe by automatically switching tools and maintaining continuous operation, allowing for simultaneous repairs across multiple nozzles without manual assistance, thus enhancing operational efficiency and reducing post-treatment needs.

Implementation Method 1

a drive mechanism that is connected to the cutting-tool support body via a ratchet mechanism. Further, when the drive mechanism is driven in a predetermined forward direction, the ratchet mechanism engages to rotate the cutting-tool support body, and when the drive mechanism is driven in an opposite direction, the ratchet mechanism restricts rotations of the cutting-tool support body

Methodology Applied
Scientific EffectRatchet mechanism: Ratchet

Implementation Method 2

a fixing structure that supplies fluid to between the fitted rotating shaft and the switching-unit main body and presses the fitted rotating shaft to the switching-unit main body, thereby fixing the fitted rotating shaft

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP2524754B1Repair device
Publication Date: 2016.06.29 MITSUBISHI HEAVY IND LTD
  • EP2524754B1 patent drawingFigure 1
  • EP2524754B1 patent drawingFigure 2
  • EP2524754B1 patent drawingFigure 3~4

AI summary

This repair device includes a casing, a slide shaft slidably arranged with respect to the casing, a turn table rotatably arranged with respect to the slide shaft, and a cutting mechanism installed on the turn table and including cutting tools. The turn table is rotationally displaced while the slide shaft slides in an axial direction, so that the cutting tools helically turn to cut an inner periphery of a nozzle. The cutting mechanism includes a cutting-tool switching unit that switches the cutting tools.