The most effective and common decontamination process employs chemical methods. Irradiated corrosion products increase the doses received by personnel in the nuclear power plant, and they should be removed from these elements in order to adhere to the guiding principle of radiation safety, “ALARA” (as low as reasonably achievable). The 60Co is produced when 59Co is activated by thermal neutrons in an (n, γ) reaction. However, the biggest problem is posed by long-lived 60Co, generated from 59Co, which is the natural cobalt isotope present in the construction materials. Among the radioactive corrosion products, the most important are long-lived nuclides (e.g., 60Co, 65Zn, 110mAg, and 54Mn) and short-lived nuclides (e.g., 58Co, 59Fe, 51Cr, and 124Sb). Following activation, the material is either dissolved or eroded from the surface, such that it is transported by the reactor coolant to a different area of the reactor coolant system. The metallic particles and metal cations that are released from the solid surface into the coolant can be deposited on the piping and/or the reactor core surfaces, where they are exposed to neutrons. The operational parameters often lead to corrosion on the metal surface and erosion of the corrosion film. During the operation of a nuclear power plant (NPP), high temperature water is continuously recirculated through the reactor coolant system.
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