Nuclear Fuel Element Diffusion Barrier Layer

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Solution Overview

Problem

In nuclear fuel elements, interatomic diffusion between fuel and cladding materials leads to undesirable alloying and degradation, especially at high burn-ups, which affects the mechanical properties and efficiency of nuclear reactors.

Innovation Solution

A diffusion barrier layer, comprising multiple layers with different materials, is introduced between the fuel and cladding to mitigate interatomic diffusion, maintaining the integrity and performance of the fuel and cladding by minimizing the formation of compounds at their interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a diffusion barrier layer is introduced between fuel and cladding, then interatomic diffusion is reduced and material integrity is maintained, but device complexity increases due to additional layers

Engineering Contradiction:
Improvematerial integrityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A diffusion barrier layer comprising an inner layer and an outer layer is introduced between the fuel and cladding materials. The inner layer is in contact with the fuel and the outer layer is in contact with the cladding material, acting as an intermediary to prevent direct contact and interatomic diffusion between fuel and cladding, thereby maintaining material integrity while managing the added structural complexity through functional segmentation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple layers with different materials are used, then diffusion mitigation is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvediffusion barrier effectivenessVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The diffusion barrier layer is segmented into an inner layer and an outer layer with different materials optimized for their respective functions. The inner layer contacts the fuel and the outer layer contacts the cladding material, allowing each layer to be tailored for optimal performance while managing manufacturing complexity through modular design and specialized functionality distribution.

Inventive Principle:
Principle #1Segmentation

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 diffusion barrier effectively reduces interatomic diffusion, maintaining the structural integrity and performance of the fuel and cladding across a wide range of temperatures, thereby enhancing the operational lifespan and efficiency of nuclear fuel elements.

Implementation Method 1

interatomic diffusion between fuel and cladding materials leads to undesirable alloying and degradation

Methodology Applied
Scientific EffectInteratomic diffusion: Diffusion

Data Source

PatentEP2939243B1Nuclear fuel element
Publication Date: 2019.02.06 TERRAPOWER LLC
  • EP2939243B1 patent drawingFigure 1a
  • EP2939243B1 patent drawingFigure 1b
  • EP2939243B1 patent drawingFigure 2a~2b

AI summary

A fuel assemblies article comprise an annular nuclear fuel; a liner disposed exterior to the annular nuclear fuel; and a cladding layer disposed exterior to the liner. The liner may include a first region disposed adjacent the nuclear fuel and including a first material, and a second region disposed adjacent the cladding layer and including a second material that is different from the first material. The fuel may include at least about 90 wt % U and a refractory material, which may include at least one element chosen from Nb, Mo, Ta, W, Re, Zr, V, Ti, Cr, Ru, Rh, Os, Ir, and Hf. The fuel may include additional burnable poisons, such as boron, gadolinium, or indium.