Recycling of nuclear liquid waste with boron control

A method of liquid waste processing for a nuclear power plant (NPP) with boron control, wherein a waste comprises sodium and potassium salts, the method including:

• a) introduction of calcium nitrate into a borate solution to provide a resulting composition, precipitation of calcium borate, and separation of the calcium borate from a mother liquor of the separated calcium borate;
• b) obtaining solutions of boric acid and sodium and potassium hydroxides;
• and
• c) electrodialysis with the use of an electrodialysis device with cation-exchange and anion-exchange membranes;
• wherein in step a) the borate solution, as sodium and potassium salts, comprises nitrates and sulphates of both sodium and potassium, wherein the introduction of calcium nitrate into the borate solution causes a co-precipitation of the calcium borate and calcium sulphate;
• wherein in step b) the obtaining the solution of boric acid is achieved by treating the co-precipitated calcium borate and calcium sulphate with a solution of nitric acid and separating the calcium sulfate precipitate from a solution of calcium borate, which is followed by treating the solution of calcium borate with nitric acid to cause formation of a precipitate of boric acid and a solution of calcium nitrate, and separating and drying the precipitate of boric acid;
• and
• wherein step c) comprises directly subjecting the mother liquor to electrodialysis to obtain solutions of nitric acid and sodium and potassium hydroxides.