Boron Particle Cementitious Shielding for Neutron Capture
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Solution Overview
Problem
Traditional concrete shielding in nuclear power facilities is inadequate as it leaves biological shielding elements exposed to neutron damage, leading to degradation over time due to radiation-induced volumetric expansion and alkali-silica reactions, despite using boron aggregates for neutron absorption.
Innovation Solution
A cementitious shielding composition with fine aggregates, hydrogenous compounds, hydraulic compounds, and boron particles, where boron particles are dispersed homogeneously with a maximum dimension of 100 microns or less, providing enhanced neutron shielding and reducing radiation-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional concrete shielding with large boron aggregates (>1/4 in.) is used, then neutron absorption capability is provided, but homogeneous dispersion is not achieved leading to localized shielding gaps and heterogeneous radiation damage
Solution Approach 1:
The invention segments the boron aggregate into progressively smaller size ranges across multiple aggregate fractions (e.g., 0-30 mesh, 30-50 mesh, 50-70 mesh, 70-100 mesh). This segmentation allows finer particles to fill gaps between larger particles, achieving homogeneous dispersion throughout the concrete matrix while maintaining effective neutron absorption capability.
Solution Approach 2:
The invention applies local quality by creating zones of different aggregate sizes within the concrete shielding structure. Smaller boron aggregates are distributed in regions where larger aggregates create gaps, ensuring uniform neutron attenuation throughout the structure while preventing localized over-concentration that would cause heterogeneous radiation damage.
2Reliability
If large boron aggregates are used for neutron absorption, then neutron shielding function is provided, but radiation-induced volumetric expansion and alkali-silica reaction susceptibility increase over time
Solution Approach 1:
The invention changes the critical parameter of aggregate size from large (>1/4 in.) to small (100 microns or less, with specific ranges up to 70-100 mesh). This parameter change reduces the surface area-to-volume ratio of boron aggregates, minimizing their susceptibility to radiation-induced volumetric expansion and alkali-silica reactions while preserving neutron absorption functionality through increased total surface area.
Solution Approach 2:
The invention creates a composite aggregate system combining multiple size fractions of boron-containing particles (0-30 mesh, 30-50 mesh, 50-70 mesh, 70-100 mesh) with concrete matrix. This composite structure provides both effective neutron shielding and improved durability by distributing radiation damage across numerous small particles rather than concentrating it in few large aggregates.
3Reliability
If heterogeneous aggregate dispersion is present, then neutron absorption occurs, but biological shielding elements remain exposed to neutron damage
Solution Approach 1:
The invention segments boron aggregates into fine particles (100 microns or less) that can be uniformly distributed throughout the concrete matrix. This segmentation ensures continuous neutron attenuation throughout the shielding structure, eliminating gaps and exposed regions that would occur with heterogeneous dispersion of large aggregates.
Solution Approach 2:
The invention achieves homogeneity by using fine boron aggregates (100 microns or less) that disperse uniformly throughout the concrete shielding elements. This homogeneous distribution ensures consistent neutron absorption throughout the entire structure, preventing localized regions of high radiation exposure to biological shielding elements.
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 cementitious shielding composition effectively reduces neutron flux and extends the service life of concrete structures by minimizing radiation-induced damage, offering exceptional shielding against fast, epithermal, and thermal neutrons, and can be applied as a coating or pre-formed panels for quick assembly and disassembly.
Implementation Method 1
boron particles are present separately from the fine aggregate, the hydrogenous compounds, the hydraulic compounds... wherein the boron particles comprise a boron compound, elemental boron, or a combination thereof
Implementation Method 2
hydrogenous compounds... wherein the boron particles are dispersed homogeneously in the cementitious shielding composition
Data Source
AI summary
The present disclosure provides for cementitious shielding compositions, methods of making the cementitious shielding composition, structures incorporating the concrete cementitious shielding composition, and the like, where the cementitious shielding composition includes elemental boron and/or a boron compound, for example as boron particles. The boron particles can be homogeneously distributed throughout the cementitious shielding composition and can have a largest least dimension of about 100 microns or less. The present disclosure, in some aspects, can reduce or eliminate problems associated with minerals found in concrete aggregates, because those materials are degraded over time by neutron radiation, which leads to disorganized lattice structures, manifested as damage by radiation-induced volumetric expansion (RIVE), and potentially further damage from alkali-silica reaction (ASR).