Nuclear Fuel Assembly Anti-Debris Filter Design

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Solution Overview

Problem

Existing fuel assembly designs for nuclear reactors are ineffective in retaining foreign objects, leading to significant depressurization of fuel elements and increased hydraulic resistance, with current anti-debris filters either being complex to manufacture or inefficient in capturing large or flat foreign objects.

Innovation Solution

The design incorporates a novel anti-debris filter comprising groups of rectilinear plates installed at specific angles within the bottom nozzle, forming rectangular channels that redirect coolant flow to effectively capture foreign objects while minimizing hydraulic resistance, using modern cutting technologies like digital gas-laser cutting or additive manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional anti-debris filters are installed in fuel assemblies, then foreign objects can be retained, but the filters are complex to manufacture and ineffective in capturing large or flat foreign objects

Engineering Contradiction:

Improveforeign object retention efficiencyVSAvoidfilter structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The filter screen is divided into multiple rectangular cells formed by perpendicular longitudinal and transverse bars, creating a grid structure that simplifies manufacturing while maintaining effectiveness against various foreign object shapes and sizes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The filter bars are arranged in two perpendicular directions (longitudinal and transverse), creating a two-dimensional grid that effectively captures both large flat objects and smaller cylindrical objects that would pass through conventional single-direction filters

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If conventional carrier grids with large apertures are used, then coolant flow is maintained, but foreign objects of large dimensions can pass through into the fuel elements bundle

Engineering Contradiction:

Improvecoolant flow rateVSAvoidforeign object retention

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The carrier grid aperture is segmented by adding longitudinal and transverse filter bars that divide the large aperture into multiple smaller rectangular cells, preventing foreign objects from passing through while maintaining overall coolant flow through the grid

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The filter bars integrated into the carrier grid serve multiple functions: they act as structural support elements for the carrier grid while simultaneously functioning as a filter to retain foreign objects, eliminating the need for separate filter components

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If conventional filters with small apertures are used, then foreign objects are retained, but hydraulic resistance increases significantly

Engineering Contradiction:

Improveforeign object retentionVSAvoidhydraulic resistance

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The filter bars have varying dimensions with the screen portion having smaller cross-section than the support portion, creating local quality differences that provide effective filtration while maintaining adequate flow passages to minimize hydraulic resistance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The filter bars extend beyond the minimum required length to provide adequate filtration effectiveness, with the support portion being longer than the screen portion to ensure structural stability and filtration performance without excessive hydraulic resistance

Inventive Principle:

Principle #16Partial or excessive 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

This design enhances the retention efficiency of foreign objects, reduces hydraulic resistance, and simplifies manufacturing, making it more reliable and cost-effective for mass production.

Implementation Method 1

forming rectangular channels that redirect coolant flow to effectively capture foreign objects while minimizing hydraulic resistance

Methodology Applied

Scientific EffectFluid flow redirection:

Data Source

PatentUS11437154B2Nuclear fuel assembly having a filter for retention of foreign objects in the coolant

Publication Date: 2022.09.06 JOINT CO TVEL

AI summary

Fuel assemblies of nuclear reactors that increase the efficiency of a filter for retention of foreign objects in the coolant while maintaining the hydraulic resistance of the fuel assembly at the same level. The nuclear reactor's fuel assembly comprises a head, a fuel elements bundle, spacer grids and the filter for retention of the foreign objects. The filter is installed in the bottom nozzle of a fuel assembly and is made in the form of rectilinear plates' groups, located in the cross section of the bottom nozzle.