CONTROL ROD DRIVE MECHANISM FOR HIGH TEMPERATURE GAS COOLED REACTOR

摘要

PURPOSE:To prevent a life shortening of a wire rope caused by metal contact corrosion and to intend improvement of operational efficiency of a nuclear reactor by forming an electrically insulating film which has a higher hardness than the rope, on whole contacting surface of a drum and a guide pulley with the rope. CONSTITUTION:A wire rope 6 is contacted with and guided by a guide pulley 16 which is a guide pulley parent material 16a coated by a ceramic coating film 16b by spraying of an electrically insulating substance of which hardness is higher than that of the rope 6, such as a ceramic, upto a required thickness. Making a supporting point of the guide pulley 16 to be a boundary, the downward rope 6 is pulled vertically by load of a control rod, and the upward rope 6 is wound around a drum 17 having a ceramic coating film 17b which is formed on the whole contacting surface of the drum parent material 17a with the rope 6, at a certain angle to the vertical direction. With this procedure, metal contact corrosion caused by a local cell which often becomes a problem in case of metals to be contacted one another, can be avoided. Also, as the hardness of the ceramic films 156b and 17b are higher than that of the rope 6, the insulating layers are scraped off by the rope 6 and the metals contact one another after a certain time, and thereby there is no possibility for the contact corrosion to occur.