170Tm gamma-ray radiography of the small diameter tube

In recent years, there has been a great interest taken in the method of nondestructive testing on the welding joints of F.B.R. (Fast Breeding Reactors) steam generator tubes. The authors have investigated on the radiographic fault sensitivity of small diameter and thin tubes. We compared with the experimental values and the theoretical values of the fault sensitivity, changing variously tube diameter, thickness, radiation source size, and distance between the film and the source. In case of calculation, the radiographic fault sensitivity was measured through the film contrast. According to the results of comparison between the theoretical value and the experimental value, the theoretical value was some different from the experimental value. The difference between the both results seems to be caused by an inappropriate build up factor. Furthermore, We have obtained various data on the Tm-170 gamma ray radiography of the thin thickness and small diameter tubes. (auth.)