Abstract: In response to the demand for digital radiographic testing of nuclear power welds, a simulation model for the radiographic testing of typical defects in stainless steel butt welds was established using the CIVA simulation software. Simulation experiments and probability of detection (POD) analysis were conducted for film radiography testing of spherical defects and linear defects, as well as digital radiography (DR) testing. The simulation test results showed that the minimum detectable diameter of spherical defects by film radiography was 0.35mm at a probability of 90% and giving 95% confident level, and the minimum depth of linear defects with a length of 1mm and a width of 0.2mm that could be detected was 0.286mm. The minimum detectable diameter of spherical defects was 0.412mm at a probability of 90% and giving 95% confident level, and the minimum depth of linear defects with a length of 1mm and a width of 0.2mm that could be detected was 0.188mm. DR detection (2x imaging) had slightly lower ability to detect spherical defects than film radiography, and better ability to detect linear defects than film radiography. Real butt weld DR testing was conducted, and the results of pore defect detection were consistent with the simulation results, the test data can be used to guide the promotion and application of DR testing for nuclear power welds.