On December 9, 1986, in the feed water piping for No.2 plant in the Surry Nuclear Power Plant, Virginia Electric and Power Company, a pipe rupture accident occurred. The outline of the accident and the results of analysis and evaluation from the viewpoint of the design, material, water flow, water chemistry, fractography and so on of the piping have been published. In this report, on the basis of the published data and information on this accident, the experience of the piping reliability verifying test carried out by Japan Atomic Energy Research Institute, and the results of inspection and maintenance of pipings in Japanese nuclear power stations, the results of investigation, examination and evaluation of this accident are described. As the contents of this report, the outline of No.2 plant in the Surry Nuclear Power Station, the accident sequence the situation and cause of the accident, the analysis of the rupture, the analysis of the pipe whipping, and the response after the accident in USA are included. Moreover, the situation of the inspection and maintenance of the piping in the same system in Japanese nuclear power stations is reported. The No.2 plant is a three-loop type PWR plant of 775,000 kW, and the place of rupture was an 18 in elbow on the inlet side of a main feed pump. The cause of rupture was the decrease of wall thickness due to erosion-corrosion. (Kako, I.).