Solidification/Stabilization Technology for Radioactive Wastes Using Cement: An Appraisal

Abstract

Across the world, any activity associated with the nuclear fuel cycle such as nuclear facility operation and decommissioning that produces radioactive materials generates ultramodern civilian radioactive waste, which is quite hazardous to human health and the ecosystem. Therefore, the development of effectual and commanding management is the need of the hour to make certain the sustainability of the nuclear industries. During the management process of waste, its immobilization is one of the key activities conducted with a view to producing a durable waste form which can perform with sustainability for longer time frames. The cementation of radioactive waste is a widespread move towards its encapsulation, solidification, and finally disposal. Conventionally, Portland cement (PC) is expansively employed as an encapsulant material for storage, transportation and, more significantly, as a radiation safeguard to vigorous several radioactive waste streams. Cement solidification/stabilization (S/S) is the most widely employed treatment technique for radioactive wastes due to its superb structural strength and shielding effects. On the other hand, the eye-catching pros of cement such as the higher mechanical strength of the resulting solidified waste form, trouble-free operation and cost-effectiveness have attracted researchers to employ it most commonly for the immobilization of radionuclides. In the interest to boost the solidified waste performances, such as their mechanical properties, durability, and reduction in the leaching of radionuclides, vast attempts have been made in the past to enhance the cementation technology. Additionally, special types of cement were developed based on Portland cement to solidify these perilous radioactive wastes. The present paper reviews not only the solidification/stabilization technology of radioactive wastes using cement but also addresses the challenges that stand in the path of the design of durable cementitious waste forms for these problematical functioning wastes. In addition, the manuscript presents a review of modern cement technologies for the S/S of radioactive waste, taking into consideration the engineering attributes and chemistry of pure cement, cement incorporated with SCM, calcium sulpho–aluminate-based cement, magnesium-based cement, along with their applications in the S/S of hazardous radioactive wastes.

Permeable Concrete Barriers to Control Water Pollution: A Review

“…As mentioned in Section 1, the presence of amorphous and crystalline hydration phases within the hardened permeable concrete provides sites for the chemical and physical entrapment of different anions and cations. This structural feature is employed in permeable concrete to remove different organic and inorganic pollutants from the water and entrap them within the material structure [6,8,12,[15][16][17][18][19]21,24,25,[27][28][29][30][31]36,38,40,41,48,49,62,63,93,103,[151][152][153]. In this respect, monolith samples of permeable concrete are prepared either in the form of disks, cylinders, or cubes, characterized, and then tested for their potential application in removing pollutants (Figure 10).…”

“…Conventional cement-based materials are heavily used in the construction sector and in environmental protection and restoration. In particular, the application of these materials in environmental protection encompass many fields, including rock repair and enforcement, the design of disposal facilities for hazardous and radioactive wastes, the stabilization and solidification of hazardous and radioactive contaminants, and water and wastewater treatment [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. This wide range of applications is supported by the low cost of these materials and their availability, the accumulated knowledge and experience from operating these materials, and the ease of engineering the hardened materials that ensures the attainment of the required performances.…”

“…Permeable concrete, also known as pervious concrete, is a subclass of cement-based materials that is tailored to have a characteristic interconnected and tortuous macroporous structure by eliminating the use of fine aggregates [22][23][24][25]. This subclass of cement-based materials is receiving increased interest in research to enhance its application in the prevention and control of water pollution due to its following characteristics [5,8,[16][17][18][19][20]22,[25][26][27][28][29][30][31]:…”

Evaluation of the Solidification of Radioactive Wastes Using Blast Furnace Slag as a Solidifying Agent

“…Of those in operation, 68% and 24.5% are ancient facilities with average life spans longer than 30 and 40 years, respectively, and worldwide decommissioning processes are expected to increase gradually [2,3]. When decommissioning nuclear facilities, hundreds of thousands of tons of various wastes, such as concrete, metal, soil, and liquid waste, are generated; it has become a pending global issue to acquire technologies related to volume reduction, solidification and stabilization, and recycling [4,5]. Generally, there are no general methods to estimate the amount of waste generated from the decommissioning of nuclear power plants because it is very different depending on the type of facility, operating history, and regulatory standards.…”

Recent progress in high-performance environmental impacts of the removal of radionuclides from wastewater based on metal–organic frameworks: a review

“…[1][2][3][4] The waste from these nuclear processes contains a high level of liquid, which contains many radioactive ions. 5,6 The eld of nuclear research, in addition to nuclear power plants, non-peaceful uses of nuclear energy as lethal weapons, and nuclear accidents, besides mining, is the most dangerous source of radioactive elements. 7,8 Some of these radioactive elements exist naturally in the minerals of monazite and thorite.…”