Abstract: The application of concentration by evaporation used nuclear fuel reprocessing plant has been summarized in this article. A conclusion was drawn that concentration by evaporation is a key technology in reprocessing plant which is mainly used in recycling of nitric acid, water and reduction of radioactivity discharge. The main applications are listed as follows. The liquid releasing from extraction units, such as 1AW, 2AW and 2DW, is high concentration of nitric acid during the concentration by evaporation of them so denitration with addition of reductant is necessary to remain the concentration of HNO₃ below 3 mol/L and temperature below 100 ℃ and avoid corrosion of the evaporator. Another liquid of the same high concentration HNO₃ is the mother liquor from plutonium oxalate precipitation process and the destruction of oxalic acid should be an important issue besides the denitration during concentration by evaporation. Some liquids with low HNO₃ concentration, for example, 1CU, 2EU and 2BP, and great variety of solutions generated from the startup, shutdown and abnormal operation also need to be concentrated by evaporation. Based on the analysis, it is found that concentration by evaporation can simplify and optimize the design and operation of reprocessing plant for its effective decontamination, high operation flexibility.