Uranium (U) and plutonium (Pu) separation technology in Purex process

The invention belongs to the technical field of nuclear fuel postprocessing, and discloses a uranium (U) and plutonium (Pu) separation technology in a Purex process. According to the uranium and plutonium separation technology, Pu (IV) in 1BF material flow is reduced to Pu (III) in 1B tank by use of reducing agent 1BX and supplement extractant 1BS to enable plutonium to get into an aqueous phase and uranium to be retained in an organic phase, and uranium and plutonium separation is realized. The reducing agent 1BX which is used comprises 0.1-0.2 mol/L of formaldoxime, 0.35-0.5 mol/L of NO and 0.35-0.5 mol/L of H ; the flow ratio of 1BF:1BX is 1-4, and the flow ratio of 1BF:1BS is 4-6. The uranium and plutonium separation technology has the characteristics that the plutonium recovery rate is high, and the purification coefficients of removal of plutonium from uranium and removal of uranium from plutonium are large.