Integrated experimental and FLUKA simulation for enhanced radiation safety in open-ceiling radiographic testing facilities

Radiographic testing (RT) is a critical non-destructive testing method for ensuring the structural integrity of pipe welds through quantitative detection of internal defects. However, radiation safety concerns often lead to overly conservative regulatory restrictions, particularly affecting open-ceiling radiographic facilities through excessive limitations on irradiation direction and shielding, thereby reducing productivity. This study conducted quantitative analyses and on-site radiation measurements under varying irradiation angles and shielding conditions in an open-ceiling RT facility located within a pipe fabrication workshop. Radiation dose distributions were estimated using Monte Carlo simulations with the FLUKA code, and results were validated against experimental measurements through relative error analysis. Under the most stringent upward irradiation condition, compliance with the public dose rate limit of 1<i>µ</i>Sv h^-1was successfully achieved using a tungsten collimator and minimal lead shielding. These results underscore the importance of adopting scientifically justified evaluation frameworks for radiation safety in non-enclosed RT facilities. The proposed approach demonstrates that achieving both radiation safety and operational flexibility is feasible without requiring fully enclosed shielding structures, thereby significantly enhancing inspection efficiency and industrial productivity.