The implementation of radiation shielding is dependent on the passage of intrinsically and extrinsically ionizing radiation via matter. The intensity and permitted radioactive dosage for a given site are defined, and the aim is to calculate the type of shielding and its constituent material. This article discusses the materials which are extensively employed for radiation shielding as well as the latest research focused on this topic.
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What is Radiation Shielding?
The United States Nuclear Regulatory Commission (USNRC) defines it as the process of radiation attenuation achieved by placing an absorbent substance between an individual, a workspace, or a radiation-sensitive instrument and any emitting radioactive source. The increased usage of radioactive substances is creating radioactive contamination, necessitating the development of improved substances to safeguard people.
Radiation may be a severe hazard in nuclear power plants, commercial or clinical x-ray installations, radionuclide initiatives, collider operations, and a variety of other situations. Radiation exposure, even in smaller concentrations, is extremely hazardous to people of all ages as well as the ecosystem. As a result, the adoption of appropriate shields is a critical need for ensuring the safety of nuclear radiation technologies.
Are All Materials Effective for Radiation Shielding?
Radiation emissions can include gamma radiation, neutron radiation, X-rays, etc. Specific materials are useful in protection against a specific type of radiation while the same material might not be effective for any other. Tungsten can efficiently absorb gamma radiation, but it may also create supplementary gamma radiation when subjected to neutron radiation shielding.
Lead - The Absolute Choice for X-rays and Gamma Shielding
Lead has long been considered "the element of choice" for radiation shielding due to its attenuating properties.
Lead is a corrosion-resistive and malleable metal. Lead's high density (11.34 grams per cubic centimeter) makes it an effective barrier against X-ray and gamma-ray radiation. Other key features, including a significant level of application flexibility, exceptional stability, and high atomic number, as well as its availability in a variety of forms, make it the best choice.
Lead Garments for Radiation Shielding
Pure lead is blended with resins and fillers to create a flexible lead vinyl film that may be worn as a radiation shielding material. The lead layers are then piled to the required thickness and inserted into the radiation shielding fabric to produce the desired lead comparability. For classic lead radiation shielding clothing, there are 3 standard levels of lead equivalent shielding: 0.25mm, 0.35mm, and 0.5mm.
Lead-Free Composites for Radiation Shielding – A Novel Study
To overcome the shortcomings of traditional lead garments, lead-free polymer composites have been developed as per research published in the journal Polymers. Because lead-impregnated shielding clothing is thick, improper handling and regular usage can degrade the fabric framework, diminishing its radiation buffering efficiency.
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The study looked into lead-free stretchable polymer composites including tin, bismuth, and cerium chemicals, both individually and in multi-layered architectures. To imitate regular wear circumstances, the materials were subjected to a simulated sweat test. After a month, this test demonstrated that only trace levels of metal substances were discharged. As a result, it was determined that the substance could function satisfactorily without compromising its radiation-shielding qualities.
Alpha and Beta Radiation Shielding
In the case of alpha and beta protection, density, rather than thickness, is a major consideration. A plastic substance or a 1-inch piece of paper may readily block alpha particles. Beta particles may be stopped using plastic, which is a more cost-effective technique. Despite the fact that lead is dense and thick, it has little influence on alpha and beta radiation.
Neutron Radiation Shielding
Because neutrons do not have a valence, they may penetrate through dense materials. To block neutron emission, low-atomic-number components are required. Hydrogen, the lightest of all the elements, is an excellent option. When neutron radiation flows through low-density hydrogen-based materials (such as water), the low-density substance creates an obstacle, blocking neutron rays from going through.
However, because the act of stopping neutrons can cause low-density substances to release gamma rays, both low- and high-density materials are routinely combined. The neutrons are elastically scattered by low-density substances, while the ensuing gamma rays are blocked by high-density materials via in-elastic scattering.
Nanomaterials for Radiation Shielding
Single-walled carbon nanotubes (SWNTs) have been used as a radiation absorbent in nanostructured materials with non-functionalized and 2–5% polymeric SWNTs in a polyethylene substrate. Boron nitride nanotubes (BNNTs) have also shown to be efficient against infrared radiation.
Nanofoams are being investigated for their potential as radiation-shielding materials. In the future, nanoparticles might be used in modules for the evolution of new radiation-shielding devices like electromagnetic or electrochemical shielding systems.
Research Advances
The nuclear shielding ability to germinate tellurite glass has just been discovered in a new study published in the Journal of Taibah University for Science. The chemical makeup of the glass had an effect on the density; it rose proportionally with the molarity of TeO2. The glasses' LACs (µ) were a crucial characteristic for characterizing photon interaction and shielding qualities. The glass with the maximum photon and electron sheltering capability was one with a chemical composition of 12.5GeO2–87.5TeO2.
Research is being carried out extensively all over the world on radiation shielding materials. Radiation shielding for space equipment and for advanced nuclear institutions is the center of focus.
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References and Further Reading
Gilys L, Griškonis E, Griškevičius P, Adlienė D. Lead Free Multilayered Polymer Composites for Radiation Shielding. Polymers. 2022. 14(9).1696. Available at: https://doi.org/10.3390/polym14091696
CMNA, 2016. What Makes Lead Good for Radiation Shielding?. [Online]
Available at: https://www.canadametal.com/lead-good-for-radiation-shielding/
Jaquith, K., 2022. 3 Different Types of Radiation Shielding Materials. [Online]
Available at: https://blog.universalmedicalinc.com/3-different-types-radiation-shielding-materials/
Nada A. et. al. (2022) Comparison of radiation shielding and elastic properties of germinate tellurite glasses with the addition of Ga2O3, Journal of Taibah University for Science. 16(1). 183-192, Available at: https://doi.org/10.1080/16583655.2022.2038468
MarShield, 2022. Choosing the Right Radiation Shielding: Factors Considered by a Shielding Materials Expert. [Online]
Available at: https://marshield.com/choosing-the-right-radiation-shielding-factors-considered-by-a-shielding-materials-expert/
More, C. V., Alsayed, Z., Badawi, M., Thabet, A., & Pawar, P. P. (2021). Polymeric composite materials for radiation shielding: a review. Environmental Chemistry Letters. 19(3). 2057-2090. Available at: https://doi.org/10.1007/s10311-021-01189-9
Med Pro, 2021. What Materials Block Radiation?. [Online]
Available at: https://med-pro.net/what-materials-block-radiation/
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