Immobilization of Phosphate Precipitate from Pyrochemical Spent Nuclear Fuel Reprocessing into a Borosilicate Matrix

The paper explores the synthesis of a borosilicate glass designed for the immobilization of phosphate-containing radioactive waste (RW) from the pyrochemical reprocessing of spent nuclear fuel. The radioactive waste inclusion accounted for 10 and 15 wt.% and the P2O5 content amounted to up to 5.8 wt.%. The paper studies the structure and properties of two glass types with quartz sand and silica used as SiO2 precursors. The study shows that the structure of such glass differs little, both types of glass are characterized by high quality indicators and comply with NP‑019-15 standards. To provide the immobilization of phosphate RW from pyrochemical spent nuclear fuel reprocessing into a borosilicate matrix, the paper proposes a vitrification method involving controlled feeding of silica-based pulp, which was tested on a laboratory installation.