SPRING FOR NUCLEAR POWER PLANT FUEL

• Main Authors: SHINDO KIICHI, HONDA TAKU, KASHIMURA EIJI
• Format: Patent
• Language: English
• Published: 15.02.1991
• Subjects: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS ANDNON-FERROUS ALLOYS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; FERROUS OR NON-FERROUS ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; NUCLEAR REACTORS; PHYSICS; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PURPOSE:To inhibit the elution of Co under the service environment by carrying out age hardening treatment in an O2-containing oxidizing gas atmosphere and forming an oxide film on the surface of a spring made of Ni-base precipitation strengthening type alloy. CONSTITUTION:A formed part made of Ni precipitation strengthening type alloy used as spacer and finger spring is prepared. This spring is degreased and cleaned and then heated in an atmosphere of oxidizing gas having partial pressure of O2 higher than that of the air to undergo oxidation treatment. By this method, a multiple oxide film can be formed on the spring surface and the elution of Co as radionuclide from the spring can be inhibited, and further, the surface dose rate of pipes and equipment can be reduced.