An irradiation target processing system for insertion and retrieving irradiation targets into and from an instrumentation tube in a nuclear reactor core comprises, a target retrieving system, target insertion system and transport gas supply system, mounted on a movable support, wherein: the target retrieving system comprises a target exit port coupled to a target storage container and exhaust system; the target insertion system comprises a target filling device, target retention tubing with target supply junction connectable to the instrumentation tube, and a target diverter coupled to the target filling device, target retention tubing and target retrieving system; and the transport gas supply system comprises a first gas supply tubing coupled to the exit port of the target retrieving system, a second gas supply tubing coupled to a junction for supplying gas to the instrumentation tube, and a transport gas supply junction coupled to the first and second gas supply tubing.