METHOD OF EXTRACTION PROCESSING OF NPP SPENT NUCLEAR FUEL Russian patent published in 2016 - IPC G21F9/06 

FIELD: power engineering.

SUBSTANCE: invention relates to the method for processing of spent nuclear fuel of nuclear power plants (NPP), and its purpose is to separate (fractionate) and confine long-lived radionuclides for their further burial in the form of stable matrices. The proposed method includes extraction of uranium (+6), plutonium (+4), neptunium (+6) and technetium (+7) from nitric-acid solution by diluted tributyl phosphate and zirconium in presence of chromium (+6) with saturation of the extract by actinides of more than 85%, and also selective recovery re-extraction of neptunium (+5) from extract with the help of solution of peroxy compounds with nitric acid content in re-extract 0.7-2.5 mole/l with re-extract flushing by a return extractant. At the same time extract of actinides added for re-extraction is diluted in the flow by return extractant until its content of actinides is 65-82% in the extract after re-extraction of neptunium and zirconium.

EFFECT: possibility for effective re-extraction of neptunium jointly with zirconium in the second block of extraction scheme, without extract washing in the heat extractor with losses of plutonium and uranium with neptunium re-extract of not more than 0,1 percent.

4 cl, 1 dwg, 1 tbl, 2 ex