METHOD AND DEVICE FOR CORROSION PREVENTION OF WETTING METALLIC MATERIAL

• Main Authors: HONDA TAKU, KASHIMURA EIJI, MINATO AKIRA
• Format: Patent
• Language: English
• Published: 15.03.1986
• Subjects: AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHINBOILERS; BLASTING; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; CONTROLLING WATER LEVEL; DIFFUSION TREATMENT OF METALLIC MATERIAL; FEED-WATER SUPPLY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HEATING; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; LIGHTING; MECHANICAL ENGINEERING; METALLURGY; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLICMATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASSC23 AND AT LEAST ONEPROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25; NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; NUCLEAR POWER PLANT; PHYSICS; PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER; REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGYGENERATION, TRANSMISSION OR DISTRIBUTION; STEAM GENERATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; WEAPONS

PURPOSE:To prevent the corrosion of the wetting metallic material of a boiling water reactor (BWR) during the shutdown of the BWR by measuring the specific conductivity of the water to be used and controlling the concn. of the dissolved oxygen in the water or the pH thereof from the measured value. CONSTITUTION:The conductivity of the water is measured by a detector 16 and the concn. of the dissolved oxygen in the water is measured by a dissolved oxygen meter 17 in order to prevent the corrosion of condensate and feed water pipings by the water in the shutdown stage of the BWR plant for the purpose of making a periodic inspection of the BWR10. The oxygen conc. is adjusted by an oxygen feeder 18 so as to attain 40ppb-40ppm when the specific conductivity is <=0.1muS/cm to decrease considerably the corrosion rate of the piping of the wetting metallic material. An inert gas is fed from the feeder 18 to deaerate the water until the concn. of the dissolved oxygen is brought to <=40ppb or ammonia or the like is fed to the water to maintain the pH at 7.5-10 passive region to prevent the corrosion of the metallic pipings if the specific conductivity exceeds 0.1muS/cm.