Abstract: This paper aims at looking into the possibility of the application of uranium (Ⅳ) nitrate to Purex processes using photochemical reduction of uranyl nitrate. A metal halide lamp, "Gallium Lamp", with a spectrum well matching the absorption spectra of uranyl nitrate, was trialproduced. Without using a filter, the ability of several reductants for photochemical reduction of uranyl ion in nitric acid solution was compared with each other. Moreover, when ethanol was used as the reductant, the effects of the concentration of HNO3, the concentration of ethanol, the initial uranyl ion concentration and the temperature on reduction yields of U(Ⅵ) to U (Ⅳ) were investigated.