Abstract: A process for the separation of uranium and plutonium as well as fission ducts including technetium from a nitric acid feed solution (fuel solution) in which said solution is treated with an extraction agent in an organic solvent to charge said agent with U, Pu and fission products including technetium by the counterflow process. The charged extraction agent containing U, Pu and fission products including technetrium is treated with a washing solution and subsequently with a reducing agent for the separation of the uranium from the plutonium and from fission products including technetium not previously washed out. To improve the separation of uranium and obtain a cleaner uranium end product, the treatment of the organic solvent containing said charged agent with reducing agent is effected in one or more stages by the crossflow process instead of by the counterflow process.