| 摘要 |
PURPOSE:To remarkably inhibit the leaching of radioactive nuclide elements such as Co into hot water from a metallic material by immersing the material in water contg. one or more among CrO4<2->, MoO4<2-> and WO4<2-> at a specified temp. to form an oxide film on the surface of the material. CONSTITUTION:A metallic material contg. radioactive nuclide elements such as Co, Ni and Fe is immersed in water contg. >=0.0005mol/l one or more among CrO4<2->, MoO4<2-> and WO4<2-> at >=100 deg.C to form a dense protective oxide film on the surface of the material. The leaching of the nuclide elements into hot water from the material is remarkably inhibited by the oxide film. Accordingly, a significant effect is produced in decreasing of the quantity of radiation exposure due to radioactive nuclides such as <60>Co, when Co alloy is used as the piping for the primary cooling system in a nuclear power plant. |
