Metallic Coated Nuclear Fuel Pellets for Reactivity Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current sintered nuclear fuel pellets face challenges with low uranium density and thermal conductivity, reactivity with water, and compatibility issues during sintering, particularly in next-generation reactors.

Innovation Solution

A sintered nuclear fuel pellet with a metallic coating of Mo, W, Cr, V, or Nb is applied to uranium-containing materials like uranium silicide, nitride, and boride, enhancing uranium density and thermal conductivity, while preventing water penetration and ensuring compatibility with uranium dioxide matrices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high density uranium-containing materials (such as uranium silicide, nitride, boride) are used to increase uranium density, then fuel economy improves, but reactivity with water increases and compatibility with uranium dioxide during sintering deteriorates

Engineering Contradiction:
Improveuranium densityVSAvoidreactivity with water and incompatibility during sintering
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

A metallic coating layer consisting of at least one metal from the group Mo, W, Cr, V, and Nb is applied to the surface of the uranium-containing material particles. This coating acts as an intermediary barrier that prevents direct contact between water and the reactive uranium-containing material, and also prevents interaction with oxidizers during sintering, thereby resolving the reactivity and compatibility issues while maintaining the high uranium density benefit

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fuel pellet is designed as a composite structure consisting of a uranium dioxide matrix with dispersed coated uranium-containing material particles. The metallic coating (Mo, W, Cr, V, or Nb) forms a protective shell around the uranium-containing material core, creating a composite particle that combines the high density benefits of uranium silicide/nitride/boride with the chemical stability of metal oxides during sintering and water resistance during operation

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional uranium dioxide is used as fuel material, then chemical stability and water resistance are maintained, but uranium density and thermal conductivity are insufficient for next generation reactors

Engineering Contradiction:
Improvechemical stability and water resistanceVSAvoiduranium density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention creates a composite fuel structure where coated uranium-containing material particles (providing high density) are dispersed in a uranium dioxide matrix (providing chemical stability). The metallic coating on the uranium-containing material particles ensures they maintain chemical stability and water resistance similar to conventional uranium dioxide, while the high density uranium-containing material core provides the desired increase in uranium density and thermal conductivity

Inventive Principle:
Principle #40Composite materials

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 metallic coating provides enhanced mechanical strength, improved thermal transport efficiency, and increased uranium density, addressing reactivity and compatibility issues, making the fuel more suitable for advanced reactors and accident-tolerant applications.

Implementation Method 1

By means of these metallic coatings, penetration of aggressive species such as water and other oxidizers (from the sintering furnace or the oxide itself) to the particles may be efficiently prevented.

Methodology Applied
Scientific EffectPhysical barrier (coating): Coatings

Implementation Method 2

According to an embodiment of the invention, the at least one metal is atomic layer deposited on the particle.

Methodology Applied
Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Implementation Method 3

According to an embodiment of the invention, the at least one metal is electro-plated on the particle.

Methodology Applied
Scientific EffectElectro-plating: Electroplating

Implementation Method 4

According to an embodiment of the invention, the at least one metal is deposited on the particle via a sol-gel technique followed by heat treatment

Methodology Applied
Scientific EffectSol-gel technique: Sol

Implementation Method 5

the compacted green pellet to be sintered to a nuclear fuel pellet having a proper mechanical strength

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3364418B1A sintered nuclear fuel pellet, a fuel rod, a fuel assembly, and a method of manufacturing a sintered nuclear fuel pellet
Publication Date: 2021.04.14 WESTINGHOUSE ELECTRIC SWEDEN AB
  • EP3364418B1 patent drawingFigure 1~5

AI summary

Disclosed are a sintered nuclear fuel pellet (10), a fuel rod, a fuel assembly and a method of manufacturing the nuclear fuel pellet. The pellet comprises a matrix (20) of UO2 and particles (21) dispersed in the matrix. The particles comprises a uranium-containing material. Each of the particles is encapsulated by a metallic coating. The uranium-containing material has a uranium density that is higher than the uranium density of UO2. The metallic coating consists of at least one metal chosen from the group of Mo, W, Cr, V and Nb.