Abstract: Radiograph flaw detection is one of the non-destructive testing methods widely used in nuclear power plants. Due to the high activity of the radioactive source to be used, if the inspection operation or management is improper, it may lead to radiation incidents or radiation accidents. This paper, based on HPR1000 unit design layout and first overhaul practice, upholds the reactor building multiple radioactive source of radiograph flaw detection risk control idea, innovatively designed a “three-step” code, combined with the judgment logic of independent research and development, in order to ensure the safe and efficient implementation of multiple radioactive source of radiograph flaw detection in the reactor building during the overhaul of HPR1000 unit. The results could provide support to improve the domestic and foreign control system in the field of radiation protection, and provide experience feedback for the same type of units at home and abroad.

Key words: HPR1000, overhaul, reactor building, multiple radioactive source of radiograph flaw detection, radiation safety management