On the manufacturing of steel casting for nuclear power plant

The production characteristics of large steel castings for PWR power plants are described, using a coolant channel head for a steam generator as a typical example of the most stringent specifications. Extremely high quality is required for the coolant channel head, and the specifications of structural material are the severest. High degree of the production techniques are thus involved: molding method including surface defect prevention, the casting process with ideal directional solidification for internal defect prevention, the measures of segregation defect reduction, employment of proper heat treatment conditions, and suitable welding process management. Further, for its nuclear power application, the systems of quality control and quality assurance must be established and employed strictly. These phases of production are now successfully carried out in the manufacture of the coolant channel head. (J.P.N.)