Graphite Neutron Reflector With BeO Inclusions for Compact Micro-Reactors

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Solution Overview

Problem

Existing neutron reflector materials and designs for micro-reactors face limitations in size, mass, power output, and thermo-mechanical performance, with beryllium-based reflectors being labor-intensive to assemble and graphite reflectors being less neutronically efficient.

Innovation Solution

A reflector assembly comprising a stationary graphite support structure with beryllium-oxide inclusions and a movable control drum system, allowing for continuous neutronic reflection and improved thermo-mechanical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If beryllium-based reflectors are used to achieve high neutron reflection efficiency, then neutron reflection performance is improved, but manufacturing complexity and labor intensity increase significantly

Engineering Contradiction:
Improveneutron reflection efficiencyVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a composite structure combining graphite matrix material with beryllium oxide inclusions. The graphite provides structural integrity and thermal stability, while the beryllium oxide inclusions provide enhanced neutron reflection properties. This composite approach achieves high neutron reflection efficiency without requiring complex assembly of pure beryllium components.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a porous graphite matrix structure in which beryllium oxide inclusions are distributed. The porous structure allows for simplified manufacturing while maintaining the neutron reflection properties through the strategic placement of beryllium oxide particles within the graphite matrix.

Inventive Principle:
Principle #31Porous materials

2Ease of manufacture

If graphite reflectors are used to simplify manufacturing, then ease of manufacture is improved, but neutron reflection efficiency decreases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidneutron reflection efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent combines graphite (easy to manufacture) with beryllium oxide inclusions (high neutron reflection) to create a composite material that achieves both manufacturing simplicity and high neutron reflection efficiency simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies beryllium oxide inclusions strategically within the graphite matrix at locations where enhanced neutron reflection is most needed, while maintaining the overall graphite structure for ease of manufacture. This localized enhancement of properties resolves the contradiction between manufacturing ease and neutron reflection efficiency.

Inventive Principle:
Principle #3Local quality

3Volume of moving object

If reflector size is reduced for compact micro-reactor design, then device compactness is improved, but neutron reflection performance deteriorates

Engineering Contradiction:
Improvereflector sizeVSAvoidneutron reflection performance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent changes the material composition parameters by incorporating beryllium oxide inclusions with specific size distributions and concentrations within the graphite matrix. This parameter change enhances the neutron reflection performance per unit volume, allowing compact reflector dimensions while maintaining or improving overall performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite structure of graphite with beryllium oxide inclusions provides high neutron reflection efficiency in a compact form factor, enabling reduced reflector size while maintaining performance requirements for compact micro-reactor designs.

Inventive Principle:
Principle #40Composite materials

4Reliability

If beryllium oxide component size is increased to improve neutron reflection, then neutron reflection efficiency is improved, but manufacturing difficulty increases

Engineering Contradiction:
Improveneutron reflection efficiencyVSAvoidmanufacturing feasibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a porous graphite matrix structure that can accommodate beryllium oxide inclusions of various sizes. The porous structure facilitates the incorporation of beryllium oxide particles while maintaining manufacturing feasibility, as the particles can be embedded within the porous framework without requiring complex assembly processes.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The composite material approach allows for the integration of beryllium oxide inclusions directly into the graphite matrix during manufacturing processes, eliminating the need for separate assembly steps and maintaining manufacturing feasibility even with larger beryllium oxide components.

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

Enhances neutron reflection efficiency, simplifies manufacturing, reduces reflector mass, and lowers costs while maintaining compact size and thermal power output.

Implementation Method 1

a beryllium-oxide inclusion positioned in each of the channels and supported by and removable from the respective channel

Methodology Applied
Scientific EffectNeutron reflection: Reflection

Implementation Method 2

graphite support structure comprising a plurality of channels defined therein

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4447070B1Enhanced graphite neutron reflector with beryllium oxide inclusions
Publication Date: 2026.02.18 WESTINGHOUSE ELECTRIC CORP
  • EP4447070B1 patent drawingFigure 1
  • EP4447070B1 patent drawingFigure 2

AI summary

A reflector assembly (150) is disclosed that is usable with a nuclear reactor (100). The reflector assembly (150) is configured to surround the reactor core (102) of the nuclear reactor (100), and comprises a stationary reflector portion (152) stationary during operation of the nuclear reactor (100) and a movable reflector portion (154) movable during operation of the nuclear reactor (100). The stationary reflector portion (152) comprises a graphite support structure (156) defining a plurality of channels (158) and a beryllium-oxide inclusion (160) positioned in each of the channels, wherein each beryllium-oxide inclusion (160) is supported by and removable from the respective channel. The movable reflector portion (154) comprises a plurality of control drums (106) rotatable relative to the graphite support structure (156).