MAGNESIUM POTASSIUM PHOSPHATE MATRIX FOR SOLIDIFICATION OF INTERMEDIATE LEVEL WASTE CONTAINING ACTINIDES AND AMMONIUM NITRATE

The compound samples based on the mineral-like magnesium potassium phosphate (MPP) matrix were synthesized upon immobilization of the intermediate level waste (ILW) imitator containing actinides and ammonium nitrate. The mechanical strength of the prepared compound samples is 10-15 MPa, including after their irradiation with an electron beam and a source of Cs-137 (absorbed dose is 1 and 0.12 MGy, respectively), after 30 cycles of freezing/thawing (–40 ...+40 ºС), and also after a 90-day immersion in water, which corresponds to the requirements of the NP-019-15 for cement compound (≥5 MPa). High hydrolytic stability of the compounds was establish in accordance with GOST R 52126-2003. It was shown that the leaching of the compound components occurs in accordance with various mechanisms, which is due to the formation of components with different solubility in the compound. Thus, the MPP matrix is promising for solidification of ILW, including high-salt actinide-containing waste of complex chemical composition.

Keywords: magnesium potassium phosphate matrix, ammonium, cesium, strontium, plutonium, americium, intermediate level waste, immobilization