Abstract: The effects of concentration of nitrous acid and temperature on photochemicalreduction of U(Ⅵ) to U(Ⅳ) in 30% TBP-terosene are studied. The retention ofuranium in organic phase, which is irradiated by gallium-lamp, is determined. Theresults show that the concentration of DBP-MBP and nitrous acid increase withirradiation time, and the retention of uranium is caused by DBP-MBP. The extra-ction behavior of Zr-Nb, Ru and Gd with 30% TBP-kerosene irradiated is inve-stigated. It is found that distribution ratios of Zr-Nb in extraction increase with inc-rease of irradiation time, no effects for Ru and Gd are observed. After irradiating30% TBP-kerosene loaded uranium and plutonium with gallium lamp, the U(VI) isreducted to U(Ⅳ), then Pu(Ⅳ) is reducted to Pu(Ⅲ) by U(Ⅳ) in organic phase.According to the condition of 1B column in Purex process, stripping plutoniumfrom uranium in organic phase is satisfactory, no effects for retention of uraniumand decontamination factors for fission products are observed.