Abstract: Aiming at the corrosion products generated during the operation of the primary circuit of the pressurized water reactor, the synergistic decontamination technology of Ce(Ⅳ) and ultrasound was studied. The 304 stainless steel was selected as the sample, and the high-pressure reaction vessel was used to simulate the corrosion environment of the primary circuit of the pressurized water reactor to produce a corrosion sample for decontamination. The effects of different Ce(Ⅳ) concentration, nitric acid concentration and ultrasonic factors on the decontamination efficiency were investigated, and the corrosion of metal matrix materials under different conditions was studied. The results show that the surface morphology of the corrosion layer produced by the high-pressure reaction vessel is dense and uniform, and there are no obvious voids and cracks. In the decontamination experiment, the concentration of Ce(Ⅳ) has a significant impact on the decontamination effect. When the concentration of cerium ammonium nitrate is 25 mmol/L, the decontamination solution has the highest decontamination efficiency on the oxide film; The effect of nitric acid concentration on the decontamination effect is not significant, and the decontamination efficiency is not much different under different nitric acid concentrations. However, with the increase of nitric acid concentration, the decontamination efficiency increases first and then decreases. When the concentration of nitric acid is 1.5 mol/L, the decontamination efficiency reaches the highest; The addition of ultrasonic factors will significantly improve the decontamination effect; The decontamination solution has good compatibility with the metal matrix material; The maximum corrosion amount of the metal matrix material is 6.25 g/m², which is far lower than the upper limit of the corrosion amount of the matrix material and the upper limit of the corrosion amount of the precision parts specified in the industry standard.

Key words: metal corrosion, Ce (Ⅳ) decontamination, ultrasonic decontamination