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Toward Sustainable Cementitious Radioactive Waste Forms: Immobilization of Problematic Operational Wastes. SUSTAINABILITY 2021. [DOI: 10.3390/su132111992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Developing effective radioactive waste management practices is essential for ensuring the sustainability of the nuclear industry. The immobilization of radioactive wastes is one of the main activities conducted during the management of these wastes; it aims to produce a durable waste form that has sustainable performance over long periods of time. In this work, the challenges that face the design of durable cementitious waste forms are addressed for problematic operational wastes. In this respect, the problematic characteristics of evaporator concentrates, spent ion exchangers, and organic liquid wastes are overviewed, and the factors that affect the durability of their cementitious waste forms are identified. A summary of potential conventional and innovative cementitious matrices is presented by reviewing the cementation practices in national programs and recent research devoted to developing durable matrices. Finally, a guide to optimize the mix design of these waste forms was proposed that includes the selection of the testing procedure, factors that affect the waste form performance, and the optimization technique. This guide was presented with special focus on leaching tests, which are a means to test the stabilization performance of nuclear waste forms.
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Li J, Xu D, Wang X, Liu K, Mao Y, Wang M, Bai Y, Wang W. Encapsulation of cesium with a solid waste-derived sulfoaluminate matrix: A circular economy approach of treating nuclear wastes with solid wastes. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:126156. [PMID: 34492936 DOI: 10.1016/j.jhazmat.2021.126156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 05/03/2021] [Accepted: 05/14/2021] [Indexed: 06/13/2023]
Abstract
It is of great importance to safely dispose nuclear wastes with the development of nuclear industries. Past approaches to this problem have included immobilizing radioactive cesium in Portland cement-based matrices; however, the leaching rates of cesium are relatively high, especially as the leaching temperature increases. This paper explores a high-efficiency and cost-effective approach for encapsulating cesium using a sulfoaluminate cement (SAC) matrix, which was prepared via synergetic use of industrial solid wastes. Leaching results showed that, the apparent diffusion coefficient values of cesium were only ~1.4 × 10-15 cm2/s and ~5 × 10-18 cm2/s at 25 ℃ and 90 ℃ leaching conditions, respectively. These values were several orders of magnitude lower when compared with previously reported values, indicating the excellent encapsulation performance of the solid-waste-based SAC for cesium. Moreover, the heavy metals contained in the industrial solid waste were also effectively immobilized. A mechanistic analysis revealed that cesium was encapsulated in the SAC matrices stably by a physical effect. Finally, a life cycle assessment and economic analysis indicated that this approach was environmental-friendly, cost-effective, and energy-saving. This work provides a promising strategy for effective encapsulation of cesium and synergetic treatment of industrial solid wastes.
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Affiliation(s)
- Jingwei Li
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Dong Xu
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Xujiang Wang
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Kang Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yanpeng Mao
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Mengmeng Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yun Bai
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Wenlong Wang
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China.
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