Its excellent properties for neutron and gamma-ray attenuation, ease of construction, and relatively low initial and operating costs make concrete the ideal material for radiation shielding. The concrete used primarily for radiation shielding may be called nuclear concrete.
To design nuclear concrete for effective radiation shielding, it is desirable to understand the types of radiation and the risks that result.
The most common types of radiation considered in the design of biological shields are electromagnetic waves and atomic particles.
In the category of electromagnetic waves, high-energy, high-frequency waves, also known as x-and-gamma rays, require users to shield.
These waves are similar to light rays but have higher energy with higher penetration power. Both x-rays and gamma rays.
They are highly penetrating and can be adequately absorbed by the appropriate thickness of a specially constructed nuclear concrete shield.
Atomic particles, on the other hand, consist of neutrons, protons, alpha and beta particles of atomic nuclei.
In all of these, neutrons do not charge and are not affected by electric fields until they collide with the nucleus.
On the other hand, protons and alpha and beta particles carry electric charges that interact with the electric field around the atom of the shielding material and they lose their energy significantly.
Accelerated protons are highly penetrated at high energy levels, but their energy is eventually diminished or lost in the process of forming additional particles and thus does not constitute a separate armor problem.
The type and intensity of radiation usually determine the density and water content requirements of shielded concrete.
The effectiveness of the concrete shield against gamma rays is roughly proportional to the density of the concrete, that is, the shield is more effective at absorbing neutrons with higher density and instability.
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Collisions or scattering. On the other hand, an effective shield against neutron radiation requires higher and lower nuclear weight factors.
Hydrogen in water provides an effective light atomic weight in concrete shields to slow down the fast neutrons. Some aggregates contain crystallized water as part of their formation, known as stable water.
For this reason, high-density aggregates with high steady-water elements are often used when both gamma rays and neutron radiation are to be diluted.
This can be achieved with the use of hydrous ores. These substances contain a high percentage of hydration water. When heating concrete, some of this constant water may be lost.
Limonite and Goethite are reliable sources of hydrogen as long as the shield temperature does not exceed 200 ° C. Cobra aggregates
Probably due to their ability to retain crystallized water at elevated temperatures up to about 400 ° C.
This guarantees the source of hydrogen, which is not necessarily available in all heavy-weight aggregates. Also boron glass (boron frit)
Added to neutrons.
Sometimes materials such as Colemanite, Boron Glass (Boron Frits), and Borocalcite are added to improve the neutron attenuation properties of concrete.
However, they may adversely affect the setting and initial strength of the concrete; Therefore, experimental mixtures must be done under field conditions to determine the appropriateness of inclusion.
Alloys such as pressure-hydrated lime can be used to reduce any retarding effect with coarse sand sizes.
Radiofrequency walls are built to prevent radiation in user areas. Neutrons are the major contributor to environmental radiation, as discussed above.
However, neutrons can be dissolved in a thick material such as unstable friction or dispersion and high-density concrete, such as iron ore, which replaces cement, water, and usually sand and gravel.
Non-magnetic coarse and fine hematite (fe2O3) aggregates with an iron content of more than 60 percent and water (cement is stabilized in a hydrated mixture) is more effective in nuclear shielding.
Iron nuclei reduce the neutron energy spectrum by unstable scattering at energies greater than 1 m eV, while hydrogen nuclei (water) further compress the energy and eventually absorb the neutron with a wall thickness that inversely increases with an energy square root of several eV.
The nuclear shielding effect of high-density concrete can be improved by using artificially enriched iron oxide pellets made of hematite ore (30-35 percent iron) to the steel-making industry as a whole.
Higher-strength and slightly lower density (due to increased porosity from 1-10 microns with typical-sized holes) can help improve the atomization of high-density concrete.
Processed common concrete contains about five percent water, but rich iron oxide pellets hold more water overall, which helps with neutron attenuation. The atomic stiffness of the concrete mixture can be improved by better neutron absorption by implantation.
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