Homogeneous Radiation Shielding Material for Small Reactors
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Solution Overview
Problem
Current neutron and photon shielding technologies in nuclear reactors face challenges in enhancing attenuation characteristics, configuration flexibility, thermal performance, and durability under irradiation, particularly in small reactors designed for distributed and resilient power generation.
Innovation Solution
The implementation of a functionally graded or homogeneous shielding material combining hydrogenous materials like lithium hydride for neutron thermalization, neutron absorbers such as boron or gadolinium, photon attenuating materials like lead oxide, and thermally conductive materials like aluminum, along with insulating materials, to create a multi-functional shielding system that can be applied externally to the reactor fuel and used in control elements for improved reactivity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compositely layered shielding materials are used, then neutron and photon attenuation can be achieved, but shielding performance and economics are inferior compared to homogeneous or functionally graded materials
Solution Approach 1:
The patent combines multiple shielding materials (hydrogenous materials for neutron thermalization, neutron absorbers like boron or gadolinium, photon attenuating materials like lead oxide or tungsten, and thermally conductive materials like aluminum) into a single homogeneous mixture or functionally graded structure, eliminating the need for complex layered composites while achieving superior shielding performance and economic benefits
Solution Approach 2:
The patent creates a composite shielding material by mixing powders of different materials in specific proportions and loading them into a matrix, forming a homogeneous or functionally graded composite that integrates the beneficial properties of each component material into a unified structure with improved overall performance
2Object-affected harmful factors
If traditional shielding materials are used, then basic radiation protection is provided, but attenuation characteristics and thermal performance are insufficient
Solution Approach 1:
The patent applies functionally graded material composition where different regions of the shielding have different material proportions optimized for their specific functions: regions closer to the fuel contain more neutron-absorbing materials, while outer regions contain more photon-attenuating materials and thermally conductive materials, creating local quality variations that simultaneously improve attenuation characteristics and thermal performance
Solution Approach 2:
The patent creates a multi-functional composite shielding material that integrates neutron thermalization (hydrogenous materials), neutron absorption (boron-bearing or gadolinium-bearing materials), photon attenuation (lead oxide or tungsten), and thermal conduction (aluminum) into a single unified material system that addresses both attenuation and thermal performance requirements
3Adaptability or versatility
If simple shielding structures are used, then manufacturing is easier, but configuration flexibility and durability under irradiation are limited
Solution Approach 1:
The patent enables configuration flexibility by allowing the shielding material composition and structure to be dynamically adapted to different reactor designs and operational requirements, while the homogeneous or functionally graded structure provides consistent durability under irradiation across all configurations
Solution Approach 2:
The patent creates a durable composite shielding material where the matrix structure provides structural integrity and resistance to irradiation damage, while the mixed powder materials provide the necessary neutron and photon shielding properties, creating a unified structure that maintains both flexibility and durability
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 approach enhances neutron and photon attenuation, improves thermal conductivity, and extends the shielding's ability to endure irradiation, resulting in improved shielding performance and economic benefits compared to traditional layered materials, while also allowing for flexible configuration and enhanced control of reactor reactivity.
Implementation Method 1
a hydrogenous material (or material of another low atomic number element such as lithium) that can directly thermalize neutrons
Implementation Method 2
a neutron absorber such as boron-bearing or gadolinium-bearing material
Implementation Method 3
a photon attenuating material, such as lead oxide or tungsten, which can slow down high energy neutrons via inelastic scattering
Data Source
AI summary
Radiation shielding and methods of manufacture are disclosed. A radiation shielding apparatus includes a matrix including matrix material; and a mixture positioned in the matrix, the mixture including: a neutron thermalizing material; and a neutron absorbing material mixed with the neutron thermalizing material. A reactivity control system includes a container rotatable around an axis; a divider positioned inside the container to define two or more compartments within the container; at least one neutron absorber positioned in at least one of the two or more compartments; and at least one neutron reflector positioned in another of the two or more compartments that is fluidly isolated from the at least one of the two or more compartments. A method of manufacturing radiation shielding material includes: fabricating a matrix; generating a mixture by mixing a neutron absorbing material, a neutron thermalizing material, and additive materials; and loading the mixture into the matrix.