Leaching behaviour of and Cs disposition in a UMo powellite glass–ceramic

Phase separation and crystallization effects on the structure and durability of molybdenum borosilicate glass

“…Until now, the chemical durability of vitreous matrices containing molybdenum oxide had been approached from complex borosilicate matrices [10,66]. The approach described above, with characterization at different scales on a model glass, has enabled a mechanistic understanding of the chemical durability of heterogeneous matrices.…”

133Cs and 23Na MAS NMR Spectroscopy of Molybdate Crystallization in Model Nuclear Glasses

“…In this case, the composition of the waste‐loaded melts may be optimized to achieve, after cooling, the formation of durable complex molybdate phase assemblages confined within the separated glass. In the first instance, the glass composition may be optimized to achieve high durability because the alkali metals and molybdenum are confined within separated glass phases . In other cases, macroscopic phase separation can act to sequester Mo and concentrate alkali (Na, Cs, Li) and alkaline‐earth metals (Ca, Sr, Ba) into a complex crystalline “yellow phase”.…”

Characterization of immiscibility in calcium borosilicates used for the immobilization of Mo6+ under Au‐irradiation

“…However, waste loading is limited to ~18.5-20 wt% in French borosilicates and US aluminoborosilicates, 7,8 in order to prevent the uncontrolled crystallization of molybdates, rare-earths, silicates, and chromites, [9][10][11] which can act as carriers for radioactive cesium, strontium, or minor actinides (MAs) and lanthanides (Ce 3+ , La 3+ , Sm 3+ , Nd 3+ , Gd 3+ , Y 3+ ). 1,12,13 High concentrations of molybdenum are expected from weapons-grade waste, postoperative clean out, increased fuel utilization, or Generation IV reactors. 1,14,15 It is also a concern if increased waste loading is to be considered, as a means to minimize the final volume of waste for long-term storage.…”