Immobilization of the rare earth fraction in lanthanide phosphates LnPO4. Radiation and hydrolytic resistance of the matrix

Radiation and hydrolytic resistance of Eu0.054Gd0.014Y0.05La0.111Ce0.2515Pr0.094Nd0.3665Sm0.059PO4 with monazite structure has been studied. The powders were obtained by deposition from solutions. Ceramic specimens with relative density ~97% were obtained by Spark Plasma Sintering (heating rate Vh = 50 {\deg}C/min, sintering temperature Ts = 1070 {\deg}C, sintering time ts = 18 min). Irradiation by accelerated electrons up to dose of 10^9 Ge was found not to result in a destruction of the target phase. After the irradiation, an increasing of the leaching rate by an order of magnitude (up to ~10^{-8} g/(cm2*day)) and a reduction of the mechanical properties by 32% as compared to the non-irradiated ceramic specimen were observed.