The declared technical solution is a system and method of decontamination of both internal and external radioactively contaminated surfaces of tubular metal parts. The decontamination system includes a cutting device, a deployment device, as well as a metal plate holding device and a washing device. The decontamination method includes the stages of longitudinally cutting tubular metal elements, straightening the cut tubular metal elements into metal plates, loading metal plates into a device for holding them, washing the device for holding metal plates filled with metal plates, removing particles of contamination from metal plates in an ultrasonic bath, which filled with acid solution, treatment and removal of radioactive residue, washing of liquid residues from the device for holding metal plates, determining the levels of radioactivity of metal plates, repeating the decontamination process if the safety level is not reached, drying the contents of the device for holding metal plates. The technical result of the invention is the minimization of the amount of radioactive waste.