Phase evolution and chemical durability of co-doped Gd2Zr2O7 ceramics for nuclear waste forms. Issue 5 (June 2015)

• Record Type: Journal Article
• Authors: Lu, Xirui; Fan, Long; Shu, Xiaoyan; Su, Sijin; Ding, Yi; Yi, Facheng
• Is Part Of: Ceramics international. Volume 41:Issue 5(2015)Part A
• Page Start: 6344
• Page End: 6349
• Publication Date: 2015-06
• Subjects: (Gd1−xNdx)2(Zr1−xCex)2O7 -- Structure -- Chemical durability -- Co-doping; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2015.01.068
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: (Gd1− x Nd x )2 (Zr1− x Ce x )2 O7 (0≤ x ≤1.0) ceramics were synthesized to investigate the co-doping effects on the phase evolution and chemical durability of Gd2 Zr2 O7 based nuclear waste forms. The phase structures of these solid solutions were identified by X-ray diffraction and their chemical durability was evaluated by static leach test (Materials Characterization Center, MCC-1). The results show that the Gd2 Zr2 O7 ceramic adopts a pyrochlore structure while the co-doped (Gd1− x Nd x )2 (Zr1− x Ce x )2 O7 (0.2≤ x ≤1.0) compositions exhibit a defect fluorite structure. Moreover, the normalized release rates of each element in (Gd1− x Nd x )2 (Zr1− x Ce x )2 O7 (0≤ x ≤1.0) waste forms increase with the growing temperature and converge to constant values with enhanced leaching time. In the discussed time range (42 days), all the considered elements show a normalized release rate lower than 10 −4 g m −2 d −1 . Gd shows the highest normalized release rate of all the involved elements, while Zr shows the best chemical durability.