The free uranium content (the ratio of free uranium which is not entirely coated with SiC layer in coated fuel particles to total uranium in coated fuel particles) and the uranium content were studied and determined by laser-induced fluorimetric method and titration with a potentiometer. The sample was burned in air first

then immersed and refluxed in nitric acid to separate the free uranium with coated fuel particles to the nitric acid solution. The uranium content in sample solution can be directly measured by laser-induced fluorimetric method

other elements had no interference on the determination of uranium. The method is simpler

faster and more accurate than traditional method in uranium analysis. The method has low measurement error of below 10%

and satisfies the needs of the specifications in the manufacture of coated fuel particles.