Thermal treatment of nuclear fuel-containing Magnox sludge radioactive waste

Forty years of durability assessment of nuclear waste glass by standard methods

“…Another major change since the first dissolution tests for glass 40 years ago is their application to new heterogeneous waste forms such as highly durable ceramics and glass ceramics. Tests including the SPFT, MCC-1 and PCT, have been applied to ceramic waste forms to estimate their dissolution rate and release of elements such as plutonium [157][158][159] . Due to the higher durability of many ceramic waste forms, testing timeframes may be longer than those used for glasses to achieve measurable elements in solution.…”

Effects of magnesium on the structure of aluminoborosilicate glasses: NMR assessment of interatomic potentials models for molecular dynamics

“…As for the latter, several structural studies 10–12 have been performed to understand the structural effects of the major cations of vitreous matrices on the glass chemical durability in the aim of a deep geological disposal 13 . Some of the vitrified high level wastes deriving from nuclear plants in the United Kingdom (Magnox) 14–16 and France (AVM) 17,18 contain a non‐negligible amount of magnesium oxide (almost 5.90 wt% and between 2.5 and 7.5 wt%, respectively 17 ) deriving from the coating of non‐enriched metallic uranium fuel bars 19 . The role of this alkaline‐earth element in the structure of glasses is still subject of debate 15,20–22 because of its low coordination and short bond distance that put it on the edge between a network modifier and an intermediate network former.…”

“…Depending on the pH of the leaching solution, the incorporation of Mg in glass may enhance its alteration due to the formation of secondary phases that modify the concentration and properties of the alteration layer. 19,23 Thien et al 17 stated that Mg has two main antagonistic effects on the dissolution rate of aluminoborosilicate glasses in water, which are the precipitation of aluminous hectorite that consumes Si and increases the dissolution rate, whereas the second is the incorporation of Mg in the gel structure, increasing the surface passivation and decreasing the dissolution rate. The effect of the glass composition on these mechanisms is still not clear and an understanding of the structural role of Mg in the glass matrix is fundamental both to unveil its implication on the dissolution behavior as well as modeling its impact.…”

“…The role of this alkaline‐earth element in the structure of glasses is still subject of debate 15,20–22 because of its low coordination and short bond distance that put it on the edge between a network modifier and an intermediate network former. Depending on the pH of the leaching solution, the incorporation of Mg in glass may enhance its alteration due to the formation of secondary phases that modify the concentration and properties of the alteration layer 19,23 . Thien et al 17 .…”

“…Aluminoborosilicate glasses are key technological materials that find application in many fields, such as biomedical materials, 1 protective screens for electronic devices, 2,3 chemical and heat resistant glass containers (such as from nuclear plants in the United Kingdom (Magnox) [14][15][16] and France (AVM) 17,18 contain a non-negligible amount of magnesium oxide (almost 5.90 wt% and between 2.5 and 7.5 wt%, respectively 17 ) deriving from the coating of non-enriched metallic uranium fuel bars. 19 The role of this alkaline-earth element in the structure of glasses is still subject of debate 15,[20][21][22] because of its low coordination and short bond distance that put it on the edge between a network modifier and an intermediate network former. Depending on the pH of the leaching solution, the incorporation of Mg in glass may enhance its alteration due to the formation of secondary phases that modify the concentration and properties of the alteration layer.…”