Immobilization of cesium in alkaline activated fly ash matrix

• Published in: Journal of nuclear materials Vol. 346; no. 2; pp. 185 - 193
• Main Authors: Fernandez-Jimenez, A., Macphee, D.E., Lachowski, E.E., Palomo, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-11-2005; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; W0100; Activator; Cesium; Lixiviation; Zeolite; Microstructure; Leaching; Strength; Molecular sieve; Nuclear reactor
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2005.06.006

The immobilization potential of alkaline activated fly ash (AAFA) matrices for cesium has been investigated. The presence of Cs in the AAFA pastes, prepared using 8M NaOH solution as activator, showed no significant adverse effects on mechanical strength or microstructure, nor were significant quantities of Cs leached following application of the Toxic Characteristic Leaching Procedure (TCLP) and American Nuclear Society (ANS) 16.1 leaching protocols. Microstructural analysis shows Cs associated with the main reaction product in the AAFA suggesting that cesium is chemically bound rather than physically encapsulated. It is proposed that cesium is incorporated into the alkaline aluminosilicate gel, a precursor for zeolite formation.