Phase composition and structure of molybdenum-, copper-, and cesium-containing sodium aluminophosphate glassy materials for immobilization of high level wastes of nuclear reactors

Abstract

Molybdenum , copper , and cesium containing glass based on aluminophosphate designed to immobilize high active wastes (HAWs), which are formed at the reprocessing of spent nuclear fuel (SNF) from Atom Peaceful Big (AMB) nuclear reactor, have been synthesized and studied by means of the X ray diffraction and electron microscopy methods. After quenching the melts, glass, which partially crystallizes at annealing, is formed. The introduction of magnesium oxide in aluminophosphate glass increases its crystallization resistance; and molybdenum oxide, decreases. The samples crystallize after heat treatment with the formation of aluminum and sodium aluminum orthophosphates and solid solution of the (Na,Cs) 3-3x Al x PO 4 composition.

The effect of Fe 2 O 3 substitution for Al 2 O 3 on the phase composition and structure of sodium–aluminum–iron phosphate glasses

“…In agreement with reference data [6][7][8][9] glasses in both series studied have rather low resistance to devitrification. The glasses of series I are subject to devitrification only after annealing (slow cooling) but in the higher-P 2 O 5 glasses of series II segregation of aluminum orthophosphate (primarily phosphocristobalite) phases occurs even in the quenched samples.…”

“…Nevertheless, while the structure of simple double phosphate glasses is studied in details [1][2][3][4][5], the structure of complex phosphate glasses is investigated in less extent. Incorporation of Al 2 O 3 in alkali phosphate glasses is known to significantly increase their chemical durability that is of great practical importance especially in nuclear waste management [6][7][8]. This effect is known since the end of 1940s [1] and its typical explanation is embedding of Al 3+ cations in the phosphorus-oxygen network forming [AlO 4/2 ] − Me + units thus immobilizing alkali and alkali earth cations.…”

“…Thus, the final vitreous waste forms produced will have sodium-aluminum-iron phosphate composition. While there are many works on the study of the structure and properties of sodium aluminophosphate, and iron phosphate glasses (see, for example, [7][8][9][10][11][12][13][14][23][24][25][26][27][28][29][30][31]), information on mixed sodium iron phosphate and sodium-aluminum-iron phosphate glasses is rather limited [15][16][17][18][19][20][32][33][34][35][36][37][38].…”

Effect of Gamma Irradiation on Structural Features and Dissolution of Nuclear Waste Na–Al–P Glasses in Water

“…Crystallization of AlPO 4 can begin in the melt in the furnace with a Na 2 O content of less than 5 mol% and then continue when the melt (glass) cools down after pouring into canisters. In general, phosphotridimite and alkaline aluminum (iron) phosphates are typical products arising from the partial or complete crystallization of phosphate glass matrices [35][36][37][38][39][40][41][42][43][44][45]. At high contents of light rare earths (the Ce group), lanthanide phosphate with the structure of monazite appears, REE solubility in the aluminum-phosphate melt is determined as few wt.% [11,42,43].…”