Jet Pump Throat Cleaning Tool Standoff Control

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Solution Overview

Problem

The challenge in cleaning a jet pump assembly of a nuclear reactor without disassembly, as existing methods fail to adequately access and clean the internal surfaces effectively during shutdown for maintenance.

Innovation Solution

A cleaning tool with a spray head and rear orifice structure is inserted into the jet pump assembly, using a combination of front and rear jets to maintain a standoff distance and direct high-pressure liquid to strike internal surfaces, allowing for effective cleaning without disassembly, utilizing a wand or hose for positioning and a manipulation tool for access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the jet pump assembly is disassembled for cleaning, then adequate access to internal surfaces is achieved, but the complexity of the cleaning process increases and time is lost

Engineering Contradiction:

Improveaccess to internal surfacesVSAvoiddisassembly process

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The cleaning tool is divided into multiple functional components: a spray head with front orifices for directing cleaning fluid, rear orifices for generating reaction force, and side plates for maintaining standoff distance. This segmentation allows each component to perform its specific function independently, enabling effective cleaning without disassembly of the jet pump assembly

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A cleaning tool acts as an intermediary device that can be inserted through the inlet opening of the jet pump assembly to reach internal surfaces. The tool uses high-pressure liquid jets as a mediator to remove deposits without requiring physical contact or disassembly of the pump components

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high-pressure liquid jets are used to clean internal surfaces, then cleaning effectiveness is improved, but the risk of damaging the surfaces increases

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidsurface damage risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The cleaning tool incorporates rear orifices that direct liquid jets in the opposite direction to generate a reaction force, pushing the front face of the tool against the inner surface. This feedback mechanism automatically maintains the tool at the correct standoff distance, ensuring consistent cleaning effectiveness while preventing damage from excessive pressure

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces direct mechanical contact cleaning methods with high-pressure liquid jet cleaning. The liquid jets deliver cleaning force without physical contact, reducing the risk of mechanical damage to delicate internal surfaces while maintaining high cleaning effectiveness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the cleaning tool is inserted through the inlet opening, then disassembly is avoided, but adequate access to the throat section is limited

Engineering Contradiction:

Improvedisassembly requirementVSAvoidaccess to throat section

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The cleaning tool uses the liquid jet flow direction as an additional dimension to reach the throat section. By directing liquid jets at angles and using the reaction force from rear orifices, the tool can access surfaces that would be difficult to reach through simple linear insertion, effectively using fluid dynamics to overcome spatial constraints

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 thorough cleaning of the jet pump assembly without disassembly, ensuring effective removal of deposits and maintaining a standoff distance to prevent damage, while conserving time and costs by using high-pressure jets and adjustable orifice structures.

Implementation Method 1

driving the second liquid from a plurality of rear orifices on a rear face of the cleaning tool in a form of a plurality of rear jets to generate a reaction force to urge the front face of the cleaning tool toward the inner surface of the jet pump assembly

Methodology Applied

Scientific EffectReaction force: Reaction (physics)

Implementation Method 2

directing a plurality of front jets of a second liquid from a plurality of front orifices on the front face of the cleaning tool such that the plurality of front jets of the second liquid travel through the first liquid and strike the inner surface of the jet pump assembly

Methodology Applied

Scientific EffectHigh-pressure liquid jet impact: Jet Erosion

Data Source

PatentUS11420239B2Method of cleaning a throat section of a jet pump assembly of a nuclear reactor

Publication Date: 2022.08.23 GE HITACHI NUCLEAR ENERGY AMERICAS LLC

AI summary

A method of cleaning a jet pump assembly of a nuclear reactor may comprise inserting a cleaning tool into the jet pump assembly such that a front face of the cleaning tool is adjacent to an inner surface of the jet pump assembly and below a level of a first liquid in the jet pump assembly. The method may additionally comprise directing a plurality of front jets of a second liquid from a plurality of front orifices on the front face of the cleaning tool such that the plurality of front jets of the second liquid strikes the inner surface of the jet pump assembly. The method may further comprise maintaining a standoff distance between the front face of the cleaning tool and the inner surface of the jet pump assembly during the cleaning of the jet pump assembly.