ATR Demonstration reactor integrity verification test for the pressur tube rolled joint portion (Fiscal 1988)

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The structure of the pressure tube rolled joint portion for the ATR Demonstration Reactor is somewhat changed from that for Fugen, in order reduce the residual stress around the portion. Therefore, Constant Temperature Endurance Test and Thermal Cycle Endurance Test have been conducted under the reactor operating conditions except irradiation to examine the rolled joint integrity. (1)Constant Temperature Endurance Test. In fiscal 1988, Constant Temperature Endurance Test have been performed in the Component Test Loop for 2,033 hours under the reactor operating conditions (pressure 75kg/cm, temperature 280C) for the JP-3 specimen (total testing period 4,033 hours) and the JP-4, JP-5 specimens (total testing period 9,533 hours). After the endurance test it was found by the helium leak test that the rolled joint tightness was maintained enough. Therefore, it was confirmed that the reduction of the residual atress at the rolled joint portion which occurred at the initial stage of the operation did not affect the rolled joint tightness. (2)Thermal Cycle Endurance Test. The helium leak test and the ultrasonic flaw detection test were performed before and after Thermal Cycle Endurance Test (the unmber of thermal cycle increaced from 60 times to 140 times in fisical 1988), of which results showed the integrity of the rolled joint tightness and no crack propagation near the rolled joint portion. Therefore, it was confirmed that 140 times thermal cycle which was the design value for the reactor life of 30 years did not affect the rolled joint tightness and the initiation and propagation of a crack even for the specimen with 200 ppm hydrogen.