Abstract: On construction of certain NPP, some films cannot be positioned inside the branch subjected to examination. This situation was caused by various reasons and deviate from codes. Designing improvement, construction management and RT techniques were discussed based on RCC-M requirements. A 3D model with radiation parameters was established by Solidworks software. RT technique for branch connection, using double wall exposure with single viewing, was quantitatively analyzed by this model. Through this model optimized suggestions were proposed for radiographic testing for branch connection.