Repair of evaporator eyelet sealing face

The steam generator is category-I equipment in nuclear power plant. The gaskets of eyelet sealing face were changed every year according to overhaul plans. In 2006, the eyelet sealing face of steam generator B is found corrosive. So a special plan was made to repair it. At the beginning, a portable flange milling machine was used to mill the eyelet sealing face, after all the holes in the surface were removed, the eyelet sealing face was milled again. To control the working accuracy, the air-operated motor's rotational speed was fixed on 31 rotate per minute. To control the depth of the pedestal sit, the surface besides the eyelet sealing face was also milled. This method could be used for reference in other place. (authors)