Abstract: In this work, adsorption behaviors of uranium, neptunium and fission products on the anion resin and TBP levextrel resin were investigated. A procedure was established to remove micro neptunium from milligramme uranium. The chemical recovery of U is about 90%. The decontamination factors of Np, Ce, Ba, La are more than 1×10⁴, those of Nd, Ru are 1×10³ and those of Zr and Nb are about 1×10². The flux of high energy neutron in the miniature and pulse nuclear reactor were measured by using the reaction of ²³⁸U(n, 2n)²³⁷U. The flux of thermal neutron in the miniature and pulse nuclear reactor were measured by using the reaction of ²³⁸U(n,γ)²³⁹U. Finally, the ratios of high energy neutron in the miniature and pulse nuclear reactor were obtained.