Magnesium potassium phosphate cements to immobilize radioactive concrete wastes generated by decommissioning of nuclear power plants

Pyo, Jae‐Young; Um, Wooyong; Heo, Jong

doi:10.1016/j.net.2021.01.005

Cited by 32 publications

(10 citation statements)

References 36 publications

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“…Magnesium phosphate cement (MPC) is widely used in synthetic boards, rapid pavement repair materials, 1 and solidification of hazardous and radioactive nuclear waste, 2,3 due to its properties such as impressive early strength, fast setting speed, minimal drying shrinkage, and the ability to be used in low-temperature environments. [4][5][6] However, the poor water resistance of MPC restricts its application in many scenarios. Extensive research focused on adjusting the pore structure or reducing the porosity size to enhance the water stability of MPC.…”

Section: Introductionmentioning

confidence: 99%

Hydration properties of magnesium phosphate cement paste mixed with metakaolin and silica fume

Liu,

Wang,

Yang

2024

Int J Applied Ceramic Tech

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Magnesium phosphate cement (MPC) exhibits a faster setting time and higher early strength, making it suitable for crack repair. However, its application in civil engineering is hindered by its fast initial hydration rate and poor water resistance. To address these limitations, metakaolin (MK) and silica fume (SF) were utilized to enhance the properties of MPC. The effects of MK and SF on the setting time, compressive strength, water resistance, hydration process, and microstructure of MPC were investigated. The results demonstrate that both MK and SF significantly prolong the setting time of MPC and improve its water resistance. The main hydration products of MPC, after incorporating MK and SF, are k‐struvite (MgKPO4·6H2O) and unreacted MgO. The presence of MgSiO3 and AlPO4 also contributes to the enhancement of compressive strength and water resistance. The incorporation of MK and SF actively participates in the hydration reaction of the MPC system. Furthermore, MgSiO3 and AlPO4 intertwine with MKP, resulting in a denser internal structure of the cured MPC, thereby improving its water resistance.

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Section: Introductionmentioning

confidence: 99%

Hydration properties of magnesium phosphate cement paste mixed with metakaolin and silica fume

Liu,

Wang,

Yang

2024

Int J Applied Ceramic Tech

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“…Magnesium potassium phosphate cements (MKPC) are receiving increasing interest for their use in a wide range of applications, including bone repair biomaterials [ 1 , 2 ], rapid repair of damaged concrete structures that require a short interruption of services, such as some highway pavement or airport runways [ 3 , 4 ], solidification of urban river dredged sludge [ 5 ], immobilization of galvanic wastes [ 6 ], stabilization and solidification of metals in a biodegradable matrix [ 7 ], 3D printing [ 8 , 9 , 10 ], and encapsulation of radioactive wastes [ 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Fillers for Magnesium Potassium Phosphate Cement (MKPC) for the Encapsulation of Low and Intermediate Level Metallic Radioactive Wastes

et al. 2023

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This study investigates the effect of coal fly ash (FA), wollastonite (WO), pumice (PM), and metakaolin (MK) as filler materials in the rheological, mechanical, chemical, and mineralogical properties of a magnesium potassium phosphate cement (MKPC), designed for the encapsulation of low and intermediate level radioactive wastes containing reactive metals. Workability, compression strength, dimensional stability, pH, chemical composition, and mineralogical properties were studied in different pastes and mortars of MKPC with a fixed molar ratio of MgO/KH2PO4 = 1. No new mineral phases were found with the addition of the fillers, denoting their low chemical impact on the MKPC system. Moreover, all formulations with a water/cement mass ratio of <0.65 presented compressive strengths higher than 30 MPa after 90 days, and pH values lower than 8.5, corresponding to the passivation zone of aluminum corrosion.

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“…It is specifically reported that 750 and 900 tons of radioactive concrete materials can be generated in the dismantling of gas-cooled and pressurized water reactors. Dismantling of the Korean research reactor (KKR-2) produced 260 tons of radioactive concrete and more than 60 tons of uranium compound contaminated concrete wastes 5 , 6 . The generation of this radioactive concrete is mainly attributed to the exposure of radioactive liquids and aerosols during the operation.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, to decrease the volume of nuclear waste during decommissioning after prolonged usage of nearly 40 years, 8–12 mm thick of contaminated concrete layer is removed by either mechanical, chemical, or biological process 5 , 8 . The traditional destructive mechanical process like shaving, abrasive blasting, and scabbling mainly results in fine secondary waste products, rough finishing, high vibration, involvement of heavy equipment, and consumption of higher labor costs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An experimental investigation of laser scabbling on cement-based materials using nanosecond fiber laser

Huynh

Mondal

Lee

2022

Sci Rep

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In this study, the influence of a pulsed fiber laser of 250 W power with a spot size of 40 µm was successfully analyzed during scabbling of six types of cement mortar and three types of ultra-high-performance concrete (UHPC). Confocal microscopy on the surface of the scabbled samples elucidated the formation of three distinct zones: glassy layer (GL), partially melted zone (PMZ), and heat-affected zone (HAZ) with unique morphological appearances. The glassy layer exhibited bubble formation, whereas cracks were spotted alongside the scabbled area. The difference in scabbling depth between the beginning and end of the process was revealed by using 3D topography images. Moreover, the development of pores and the changes in the microstructure of each zone were observed by using scanning electron microscopy (SEM). Further energy dispersive X-ray (EDX) analysis also revealed significant changes in the percentage of silicon and calcium inside the glassy layer and non-processed zone (NPZ).

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Magnesium potassium phosphate cements to immobilize radioactive concrete wastes generated by decommissioning of nuclear power plants

Cited by 32 publications

References 36 publications

Hydration properties of magnesium phosphate cement paste mixed with metakaolin and silica fume

Hydration properties of magnesium phosphate cement paste mixed with metakaolin and silica fume

Evaluation of Fillers for Magnesium Potassium Phosphate Cement (MKPC) for the Encapsulation of Low and Intermediate Level Metallic Radioactive Wastes

An experimental investigation of laser scabbling on cement-based materials using nanosecond fiber laser

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