Method for detecting plutonium content of neptunium dioxide sample

A method for detecting the plutonium content of a neptunium dioxide sample comprises the following steps: (1) preparing a nitric acid-hydrofluoric acid mixed acid solution; (2) preparing a nitric acid solution; (3) preparing a TOPO-xylene solution; (4) preparing a sodium nitrite solution; (5) preparing a plutonium standard disc; (6) dissolving the sample; (7) diluting the solution; (8) extracting and separating; (9) making the sample into a disc; and (10) detecting the sample. The harm of sample radioactivity to operators is reduced, and the measurement error caused by the influence of the americium element on the plutonium content measurement is eliminated. The analysis method for detecting the plutonium content in the neptunium can be used for determining the plutonium content in a neptunium product in a power reactor spent fuel reprocessing plant, the precision of the analysis method is better than 10%, and the adding standard recovery rate is 80-110%. The separation effect of the TOPO for extracting and s