Plutonium incorporation in phosphate and titanate ceramics for minor actinide containment

Crystal chemistry of the monazite structure

“…Among these studies, several works were dedicated to samples incorporating simultaneously tri-and tetravalent actinides as such materials could be used as radwaste matrices 217 . On this basis, the incorporation of plutonium under both +III and +IV oxidation states was mentioned 218 and correlated to the partial reduction of Pu(IV) in Pu(III) in phosphate media. Similar compounds were also obtained with cerium.…”

Comparison of microstructure and chemical durability of Ce0.9Gd0.1PO4 ceramics prepared by hot-press and pressureless sintering

“…Because of the low solubility and slow dissolution rates, these phosphates exhibit higher resistance against corrosion by the geological fluids than the borosilicate glass [1,2]. Monazite (Ln 3 þ PO 4 , monoclinic system, space group P2 1 /n, Z=4) is a natural light rare-earth orthophosphate mineral, which shows high actinides loadings, mechanical stability, chemical durability and radioresistance [11][12][13][14][15][16][17][18][19][20][21]. Moreover, monazite can incorporate trivalent and/or tetravalent actinides due to its high-structural flexibility [13][14][15][16][22][23][24][25].…”

Effect of sintering technique on mechanical property and chemical durability of Ce0.5Pr0.5PO4 ceramics

“…Extensive studies are performed in several countries on the immobilization of minor actinides in highly durable matrices [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Monazite ores are the major source of light rare earth elements, which show high actinides loadings, chemical durability, mechanical stability and radio-resistance [5,6,8,16,17,20,21,[23][24][25][26].…”