A system for radiographic inspection of welds from at least a portion of a vertical wall such as the wall of a storage tank for gas or oil wherein the wall comprising a plurality of metal plates connected by means of the welds, the system comprising a frame comprising a first sub frame arranged to be positioned, in use, on a first side of the portion of the wall and a second sub frame arranged to be positioned, in use, on a second side of the portion of the wall which lays opposite to the first side of the portion of the wall. The system comprises a radiation source which is attached to the first sub frame for transmitting electromagnetic radiation towards the weld and a radiation detector which is attached to the second sub frame for detecting radiation which has traveled through the weld for carrying out the inspection.