Garnet nuclear waste forms – Solubility at repository conditions

Study of the Hydrolytic Stability of Fine-Grained Ceramics Based on Y2.5Nd0.5Al5O12 Oxide with a Garnet Structure under Hydrothermal Conditions

“…Furthermore, it increased with increasing temperature up to 200 • C. However, the leaching rates of cations remained almost unchanged with further increasing test temperature up to 300 • C. The leaching rates achieved characterize the samples studied as having a high hydrolytic stability. The leaching rate of yttrium was comparable to the data obtained for the YAG single crystal [11]. We assume the insignificant differences observed are associated, first of all, with the presence of residual porosity as well as with more accelerated destruction of grain boundaries in YAG/Nd ceramics sintered.…”

“…The study of such compounds is very important for the immobilization of actinide elements (which constitute a special group of long-term ecologically hazardous radionuclides) in order to isolate these ones from the biosphere for the long time required for the storage and disposal. For this purpose, the world's leading laboratories are currently studying ceramic materials based on natural minerals [1]: monazite [2,3], garnet [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], kosnarite [18][19][20][21], pyrochlore [10,[22][23][24][25], scheelite [26], etc. The garnet structure is one of the most promising matrices for the MA immobilization.…”

“…In present work, a special attention was paid to the problem of studying the high-temperature hydrolytic stability of ceramics with a garnet structure. In [ 11 ], the hydrolytic stability of various garnet single crystals (including pure yttrium–aluminum garnet not doped with lanthanides) was investigated at 200 °C and a pressure of 150 bar for 28 days. The leaching rate of yttrium ranged from 1.29 × 10 −3 to 5.64 × 10 −4 g/m 2 ·day.…”

The solubility, microstructure, and chemical durability of Ce‐doped YIG ceramics designed as actinide waste forms

“…Garnet ceramics also have excellent corrosion resistance. 12,19,28 In terms of radiation resistance, Livshits et al 29,30 found the garnet structure's radiation response is structurally constrained, which means that different compositions of garnet waste have similar radiation tolerance. Hence, garnet-based ceramics could be considered as a potential matrix for immobilizing HLW.…”

An Interdisciplinary View of Interfaces: Perspectives Regarding Emergent Phase Formation

“…In addition, CeO 2 is a well-known surrogate for UO 2 , and the principal actinide components of nuclear fuel UO 2 and PuO 2 also crystallize in fluorite structured oxides [7]. Garnet structures currently being evaluated for solid-state lithium battery electrolytes such as Li 7 La 3 Zr 2 O 12 (LLZO) are similar to based garnets being evaluated for nuclear waste immobilization of lanthanide fission products [8,9]. Finally, tunnel structured materials such as hollandites which incorporate mobile alkali ions such as Li, K, and Na in tunnels have been looked at as candidate battery electrode materials [10]; current work in solid state materials synthesis in the nuclear materials realm seeks to engineer the tunnels to block the motion of larger alkali ions such as Cs for immobilization applications [11].…”