reducing radionucleide contamination of a metallic component

摘要

Apparatus for reducing radionuclide contamination of a metallic component includes a concentrated spray nozzle 16 mounted on an articulated positioning arm 26 arranged to traverse completely a surface 28 of a component of a nuclear plant upon de-commissioning and subject to radio-active contamination. The nozzle 16 is connected, as a cathode, to an electrical power source 32 to give an electrical current density of approximately 50 amps per tenth square metre with the component connected as an anode. An electrolytic treatment liquid 20, such as 5% nitric acid solution, is discharged through the nozzle 16 to react with at least any metallic oxide surface layer to dislodge or detach any radionuclide particles, such as particles of cobalt 60, attached to the surface 28. The electrolytic treatment liquid 20 drains to a shallow reservoir formed by the component or to a separate reservoir 18 and is then passed to a settling tank 10 and fine filter 20 where the radionuclides settle out or are filtered out and the liquid re-cycled.