Determination of neptunium in neptunium-uranium-plutonium mixed oxide fuel by spectrometry

The measurement condition by spectrophotometry was evaluated to measure Np content in MOX fuel containing Np. The Np concentration was obtained by measuring the 727 nm absorption peak, after the valence of Np in the sample solution was adjusted to the Np(IV). The calibration curve showed the linearity up to Np concentration 0.8 mg/ml. Though Pu and U quantity were respectively added to the Np solution to 30 times and 60 times of Np concentration, there was no effect to the Np analysis. By using this method, relative standard deviation (RSD) of the analyzed values of Np content for 2%Np - MOX fuel was about 4%. In addition, it was confirmed that the Np content could be measured without separating Np from Pu and U. This method can be sufficiently applied as a quick simple method to analyze Np content in MOX fuel containing Np. (author)