Results of LOFT program

LOFT program is the synthetic experimental program to investigate into LOCA which is the design standard accident of power LWRs and abnormal transients using a PWR of 50 MWt output. The LOFT reactor was installed in the Idaho National Engineering Laboratory, and has become the central facility for the research on the safety of LWRs in USA. The facility which can perform LOCA experiment using the whole core of an actual reactor is only the LOFT reactor in the world. The LOFT program became an international program, in which USA, Japan, West Germany, Netherlands, three north European countries, France, Austria and others participated. Japan contributed largely to the program by yearly paying 1 million dollars and sending 7 researchers. The LOFT installation is a small experimental reactor of 50 MWt output, which comprises a pressure vessel, primary cooling system, blow down pressure control system, emergency core cooling system and secondary cooling system. Large rupture experiment series, medium and small rupture experiment series, abnormal transient experiment and anticipated transient without scram experiment series were carried out, and the results are outlined. It was found that the performance of ECCS and its safety evaluation analysis have large margin. (Kako, I.)