β-SiC End Plug Composition for Sealing Ceramic Fuel Cladding

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Solution Overview

Problem

Existing methods for manufacturing end plugs for nuclear fuel elements face environmental hazards, lack of comprehensive data on materials and composition, and do not meet the structural and functional requirements of water-moderated water-cooled reactors, leading to potential disturbances in coolant flows and heat transfer properties.

Innovation Solution

The development of β-SiC-based end plugs with specific diameters and configurations, utilizing two or three coaxial cylinders for brazing with paste-like and foil braze, and a powder mixture of β-SiC, Al2O3, and Y2O3 for improved bonding and sealing, manufactured through hot pressing and sintering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a gas mixture comprising chlorine and hydrogen is used for forming nanocrystalline silicon carbide layers, then the tube layers can be formed, but ecologically hazardous gaseous hydrogen chloride is produced

Engineering Contradiction:

Improvetube layer formationVSAvoidgaseous hydrogen chloride

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the gas mixture from chlorine-containing (HCl-producing) to aluminum-based (AlH3, AlCl3 precursors that decompose to Al2O3). This parameter change eliminates harmful HCl emissions while maintaining the ability to form protective ceramic layers through alternative chemical pathways.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of using chlorine-based gases that produce harmful HCl, the patent employs aluminum-based precursors that form beneficial Al2O3 ceramic layers. The harmful chemical pathway (chlorine deposition) is replaced with a beneficial one (aluminum oxide layer formation) that provides both protection and environmental safety.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If existing plug manufacturing methods are used, then plugs can be produced, but comprehensive data on material composition and properties is lacking

Engineering Contradiction:

Improveplug productionVSAvoidmaterial composition data

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent provides complete self-documentation of material compositions, processing parameters, and resulting properties within the patent specification. All critical data (powder compositions, sintering temperatures, densities, mechanical properties) are explicitly reported, making the methodology self-sufficient and eliminating information gaps for reproduction and evaluation.

Inventive Principle:

Principle #25Self-service

3Reliability

If conventional end plug structures are used, then sealing can be achieved, but coolant flow disturbance and heat transfer degradation occur

Engineering Contradiction:

ImprovesealingVSAvoidcoolant flow and heat transfer

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies different structural qualities to different regions of the end plug. The internal sealing surface maintains tight tolerance for hermetic sealing, while the external geometry is optimized with flow-friendly contours and surface features that minimize coolant flow disturbance. This local differentiation allows simultaneous achievement of sealing reliability and thermal-hydraulic performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of prioritizing sealing at the expense of flow characteristics, the patent inverts the design approach by first optimizing for coolant flow and heat transfer, then incorporating sealing functionality. The external geometry is designed for flow efficiency, while internal features (grooves, O-ring seats, surface finishes) provide the sealing function, reversing the traditional design hierarchy.

Inventive Principle:

Principle #13The other way round (Inversion)

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 provides safe, environmentally friendly, and structurally compatible end plugs with enhanced mechanical and thermophysical properties, suitable for various reactors, simplifying the manufacturing process and ensuring reliable sealing.

Implementation Method 1

manufactured through hot pressing and sintering

Methodology Applied

Scientific EffectHot pressing:

Implementation Method 2

manufactured through hot pressing and sintering

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 3

by diffusion bonding

Methodology Applied

Scientific EffectDiffusion bonding: Diffusion Welding

Data Source

PatentUS12482575B2Method of manufacturing a nuclear fuel element end plug which contains ß-SiC, Al2O3, and Y2O3

Publication Date: 2025.11.25 AKTSIONERNOE OBSHCHESTVO VYSOKOTEKHNOLOGICHESKIJ NAUCHNO ISSLEDOVATELSKIJ INST NEORGANICHESKIKH MATERIALOV IMENI AKADKA A A BOCHVARA

AI summary

Method of manufacturing an end plug for a nuclear fuel element. The end plug includes at least two coaxial cylinders having different diameters. The end plug is configured to seal a ceramic cladding tube. The manufacturing method includes hot pressing a powder mixture comprising β-SiC, Al2O3, AND Y2O3.