Reactor Inspection Apparatus with Torque-Compensating Float

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Solution Overview

Problem

In nuclear reactors during maintenance periods, cumbersome inspection equipment often interferes with refueling operations and remotely-operated vehicles lack reliable positioning for inspections, especially when submerged in coolant.

Innovation Solution

A positioning and inspection apparatus that can be mounted on a steam dam or reactor perimeter, featuring rotatable arms and a float for torque compensation, allowing for precise and non-interfering inspection and tooling operations across the reactor without requiring refueling apparatus interaction, with power and control provided through an umbilical connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If cumbersome inspection equipment is used during maintenance periods, then inspection capability is improved, but interference with refueling operations increases

Engineering Contradiction:

Improveinspection capabilityVSAvoidinterference with refueling operations

Core Design Contradiction:

Difficulty of detecting and measuringVSObject-generated harmful factors

Solution Approach 1:

The inspection apparatus is extracted from the refueling bridge environment and mounted on the reactor pressure vessel wall, separating inspection operations from refueling operations to eliminate interference while maintaining inspection capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The reactor pressure vessel wall serves as an intermediary mounting surface, allowing inspection equipment to be positioned close to the core without requiring access from the refueling bridge, thus mediating between inspection needs and refueling operations

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If remotely-operated vehicles are used for inspections, then operator safety is improved, but positioning reliability deteriorates

Engineering Contradiction:

Improveoperator safetyVSAvoidpositioning reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The positioning system is segmented into multiple independent components: motorized rotation mechanisms for azimuth and elevation control, umbilical connections for power and control signals, and mechanical mounting structures, with redundancy in each segment to ensure reliable positioning

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Manual positioning of remotely-operated vehicles is replaced with motorized rotation mechanisms controlled by operators through umbilical connections, providing precise and reliable positioning while maintaining operator safety through remote operation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If inspection equipment is extended into the reactor, then inspection coverage is improved, but device complexity increases

Engineering Contradiction:

Improveinspection coverageVSAvoidapparatus complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The inspection apparatus uses a nested structure with an inner arm positioned within an outer arm, both rotating about the same axis, allowing compact storage when retracted and extended inspection reach when deployed, improving coverage without proportionally increasing complexity

Inventive Principle:

Principle #7Nested doll (Nesting)

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

Enables reliable and precise positioning of inspection tools across the reactor without interfering with refueling operations, ensuring accurate inspections and reducing the need for manual intervention, while maintaining compactness for easy installation and removal.

Implementation Method 1

a float may be positioned away from the shoulder so as to counter torque on the shoulder from the arms and article(s) when immersed in water

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS11257598B2Positioning and inspection apparatuses for use in nuclear reactors

Publication Date: 2022.02.22 GE HITACHI NUCLEAR ENERGY AMERICAS LLC

AI summary

Systems are provided for inspection and tooling submerged in nuclear reactors. Systems mount at the reactor edge, such as on a steam dam, to be independently operable from a refueling bridge or refueling operations. A moveable steam dam clamp may hold a position apparatus at the edge. The positioning apparatus includes a rotatable shoulder and arms move a tool, reactor component, and/or inspection device like a camera or VARD to desired and highly-determinable reactor positions. A float may counter shear and rotation on the shoulder from the arms. Motors at the shoulder with internal transmissions may rotate the shoulder and arms, or manual rotation may be used. The arms may also overlap vertically for installation and removal. Power, controls, and/or data may be provided underwater through an umbilical connection to operators.