| 摘要 |
The present invention relates to a method and a device for inspecting whether there is damage in a stud to fasten a nuclear reactor vessel and a nuclear reactor upper head which are key facilities in a nuclear power plant. More specifically, the present invention relates to the technologies of: inserting an ultrasonic probe into a center hole of a stud; automatically moving the ultrasonic probe to acquire an ultrasonic signal; and detecting a defect. Considering that the nuclear reactor is placed in a state of the high temperature and the high voltage as the nuclear reactor cooling material is heated by the high energy generated by the reaction nuclear fuels loaded in the nuclear reactor and the nuclear fission, since the high tensile stress is also applied to the stud to fasten the nuclear reactor vessel and the nuclear reactor upper head, the nuclear power plant manually performs an inspection by applying an ultrasonic inspection method during the inspection while operating the nuclear power plant. When the inspection is manually performed, an inspector analyzes an ultrasonic signal waveform of a detector at site to determine whether there is a defect, and the inspection result is completely relied on the judgment of the inspector. Furthermore, there is no means to record the inspection result and, therefore, the reliability of the inspection result can be reduced, and the objective inspection cannot be performed. To solve the problems while escaping from the existing manual inspection method, the present invention provides the method and the device capable of: automatically inspecting whether there is a defect in the stud by applying a device to insert an ultrasonic probe into a center hole of a stud and move the ultrasonic probe in an axis direction while rotating the ultrasonic probe in a rotation direction; storing the inspection result in a digital format to allow a re-evaluation and a follow-up inspection; and three-dimensionally displaying the stored inspection result to accurately evaluate the signals, thereby improving the inspection reliability. |
