Abstract: Nuclear reactors produce large amounts of spent fuel during operation. In addition to recyclable materials such as uranium and plutonium, spent fuel also contains significant amounts of fission products and highly radioactive transuranic (TRU) elements. Homogenization of nuclides in traditional post-processing technology hinders efficient fuel recycling. In order to improve the efficiency of spent fuel recycling, and to reduce the inevitable “highly radioactive waste” produced in existing spent fuel recycling processes, a novel method for pre-separating nuclides in spent fuel is disclosed. Specifically, we have developed a physical method, wherein an artificially created large temperature gradient drives the migration of fission gas bubbles in spent metallic nuclear reactor fuel. The fission gas bubbles preferentially carry fission products and transuranic elements to achieve effective pre-separation of these elements from spent fuel, lowering cost and improving efficiency of spent fuel recycling.

Abstract: The present disclosure provides a method for pre-separating nuclides in spent fuel, comprising steps: S1. generating a temperature of 1200 to 1600° C. in a center of a fuel element, and at the same time introducing a cooling medium to an outer surface of the fuel element, to introduce a temperature difference to heat the fuel element; S2. soaking cooled spent fuel in an ionic liquid to selectively dissolve fission products and transuranic elements, so that the fission products and the transuranic elements are pre-separated from the spent fuel. The method achieves the effect of pre-separating part of the fission products and transuranic elements by physical methods, and solves the problem that homogenization in traditional post-processing technology causes obstacles to nuclide separation.