Composite Uranium Silicide Fuel Pellets for Oxidation Resistance
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Solution Overview
Problem
Uranium nitride fuel's low oxidation resistance and susceptibility to water and steam oxidation/spalling pose challenges for use in Light Water Reactors (LWRs, necessitating the development of accident-tolerant fuels that can withstand radiation, high temperatures, and chemical environments.
Innovation Solution
The use of uranium silicide materials, particularly U3Si2, with a higher thermal conductivity than uranium dioxide, combined with a uranium dioxide outer layer to form a composite fuel pellet that enhances oxidation tolerance and maintains high uranium density, allowing for efficient power production while minimizing heat storage during accidents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If uranium nitride fuel is used in LWRs, then thermal conductivity and melting point are improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent applies composite materials by combining uranium nitride particles (providing high thermal conductivity and melting point) with a corrosion-resistant matrix material (providing oxidation resistance). This composite structure allows the fuel to simultaneously achieve the thermal performance of uranium nitride and the oxidation resistance of the matrix material, resolving the contradiction between improved temperature properties and deteriorated oxidation resistance.
2Temperature
If uranium nitride fuel is used in LWRs, then melting point is improved, but resistance to water and steam oxidation/spalling deteriorates
Solution Approach 1:
The composite structure combines uranium nitride particles (providing high melting point) with a corrosion-resistant matrix material (providing resistance to water and steam oxidation/spalling). The matrix material acts as a protective barrier that prevents direct contact between the uranium nitride and the corrosive LWR environment, thereby maintaining the high melting point advantage while eliminating the susceptibility to water and steam oxidation.
3Productivity
If higher burn-up fuel is used, then productivity is improved, but radiation tolerance requirements increase
Solution Approach 1:
The patent changes the material composition parameters by incorporating corrosion-resistant materials and optimizing the uranium nitride matrix composition. This allows the fuel to withstand higher burn-up levels (improved productivity) while maintaining structural integrity and resistance to radiation damage (maintained reliability), as the modified material parameters provide enhanced tolerance to the extreme conditions of high burn-up operation.
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 uranium silicide fuel pellets offer improved thermal conductivity, higher uranium density, and enhanced oxidation resistance, enabling longer reactor operation with reduced refueling needs and increased efficiency in uranium resource utilization while maintaining the oxidation tolerance of uranium dioxide.
Implementation Method 1
The at least one silicide has higher thermal conductivity than uranium dioxide
Implementation Method 2
enhances oxidation tolerance and maintains high uranium density, allowing for efficient power production while minimizing heat storage during accidents
Data Source
AI summary
Described herein are Uranium silicide materials as advanced nuclear fuel replacements for uranium dioxide fuel in light water reactors (LWRs) that have advantages over currently used uranium dioxide (UO2) via a substantially higher thermal conductivity and, thus, are capable of operating in a reactor at significantly lower temperatures for the same level of power production, plus the heat capacity of a silicide is lower than that of an oxide so that less heat is stored in the fuel that would need to be removed under accident conditions.