LI Xiuying ¹, TAO Xinyue ¹, XIAO Zhuohao ¹, KONG Lingbing ², LIU Yalun ¹, ZENG Xiaoling ¹, YANG Ke ¹, SHI Jijun ¹

(1. School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China; 2. College of New Materials and New Energies, Shenzhen Technology University, Shenzhen 518118, Guangdong, China)

Abstract: Based on iron phosphate wasteform (38waste-17Fe₂O₃-45P₂O₅, in mol%, S₁), six glassy wasteforms loaded with 30.6-34.7wt.% simulated high level nuclear waste (HLW) were prepared by replacing 2mol% Fe₂O₃ in S₁ with PbO(S₂), Cr₂O₃(S₃), La₂O₃(S₄), CeO₂(S₅), Bi₂O₃(S₆) and B₂O₃(S₇). The influences of the substitutions on structure and property of the wasteforms were studied. IR, XRD, DSC, TEC were used to examine their structure and thermal stability. Chemical durability was characterized according to their dissolution rates in 6 M HCl solution (DR_Acid) and deionized water at 90 °C (DR_Water). The substitutions of 2mol% Fe₂O₃ in S₁ with B₂O₃(S₇) and especially La₂O₃(S₄) significantly improved chemical durability and thermal stability of the wasteforms. Chemical durability and thermal stability of S₄ and S₇ are superior over or comparable with those of 40Fe₂O₃-60P₂O₅ glass (F40), respectively. The dissolution rates of all the wasteforms are equal to or less than those of most borosilicate glass based vitrified nuclear wasteforms. Waste capacities of all wasteforms are higher than those reported previously.
Key words: waste immobilization; chemical durability; thermal stability; structure