Multiple-Path Flow Restrictor Nozzle for Nuclear Reactors

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Solution Overview

Problem

Conventional devices for restricting gas flow from pressurized vessels in nuclear reactors are complex and prone to failure due to movable components, which increases the risk of malfunction during critical events like steam line breaks.

Innovation Solution

A passive flow restrictor nozzle with a monolithic structure and multiple parallel internal flow paths, including convergent, throat, and divergent sections, that secures to the vessel without moving parts, utilizing Venturi nozzle principles to control flow and minimize pressure loss, thereby stabilizing the flow and reducing the risk of failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If movable components are used to restrict gas flow, then flow restriction capability is achieved, but device complexity increases and reliability decreases

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes movable components entirely from the flow restrictor device, extracting the problematic element that caused complexity and reliability issues. The flow restriction is achieved through fixed geometric features (convergent-divergent nozzle shape) rather than movable parts, directly resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical movable component system with a fixed geometric flow control system. Instead of using moving parts to adjust or restrict flow, the invention uses the fixed shape and dimensions of the nozzle passages to control flow characteristics, eliminating mechanical complexity while maintaining flow restriction capability.

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

2Reliability

If movable components are used to restrict gas flow, then flow restriction capability is achieved, but the risk of failure increases

Engineering Contradiction:
Improverisk of failureVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes all movable components from the device, eliminating the source of potential failures associated with moving parts such as wear, seizure, or actuation failures. The flow restriction function is achieved through fixed geometric features, directly reducing failure risk while avoiding increased complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixed geometric nozzle structure performs the flow restriction function inherently through its design, without requiring external control systems, actuators, or maintenance. The structure serves itself by using its fixed shape to control flow, eliminating the need for complex control mechanisms and reducing failure risk.

Inventive Principle:
Principle #25Self-service

3Reliability

If a monolithic structure with multiple flow paths is used, then reliability increases and complexity decreases, but manufacturing precision requirements increase

Engineering Contradiction:
ImprovereliabilityVSAvoidmanufacturing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the single flow restriction function into multiple parallel flow paths within the monolithic structure. Each path has its own convergent-divergent geometry, allowing the complex flow control function to be distributed across simpler, repeating geometric units. This segmentation enables reliable flow restriction while making the manufacturing of each individual path more achievable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple flow paths into a single monolithic structure, combining several flow restriction functions into one integrated component. This merging achieves reliability through structural unity and simplicity while the internal segmentation into multiple paths maintains manufacturability by using repeating geometric patterns.

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

The solution effectively restricts gas flow without moving parts, reducing complexity and risk of failure, while maintaining efficient pressure management and flow stability, enhancing safety and operational efficiency in nuclear reactors.

Implementation Method 1

Each of the plurality of internal flow paths includes a convergent section, a throat section, and a divergent section

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentEP3729465B1Multiple-path flow restrictor nozzle
Publication Date: 2023.06.21 GE HITACHI NUCLEAR ENERGY AMERICAS LLC
  • EP3729465B1 patent drawingFigure 1
  • EP3729465B1 patent drawingFigure 2
  • EP3729465B1 patent drawingFigure 3

AI summary

A flow restrictor nozzle for a pressurized vessel of a nuclear reactor may comprise a nozzle body including an inlet face and an outlet face. The nozzle body may define a plurality of internal flow paths extending from the inlet face to the outlet face. Each of the plurality of internal flow paths may include a convergent section, a throat section, and a divergent section.