Annealing unit insertion and removal system

A system is provided which allows moving an annealing unit 62 into a general position for insertion into a nuclear reactor vessel 10 by an operator using a remotely controllable polar crane 60 and optical cameras 86 and 87 to view one or more reference holes 102 in the sealing plate 82 of the reactor vessel 10. Once the unit 62 is in the approximate position for lowering, an automated tracking system is activated which guides the unit into the vessel. The tracking system includes reference infrared emitters 104 and 106 mounted on the sealing plate 82 of the vessel 10, infrared cameras 88 and 89 to capture the image of the emitters 104 and 106, and a computer 152 to calculate the difference between a target position and an actual position and cause the polar crane 60 to position the annealing unit 62 at the target position. The cameras 86-89 are mounted on an annealing unit carrying fixture 64 which includes camera tracks 90 over which the cameras 86-89 can be retracted to prevent heat damage to the cameras 86-89 during annealing. Contact sensors can be provided on the annealing unit 62 to detect contact between the unit 62 and the vessel 10 during insertion and removal. A range determination unit 110 can also be provided to determine the distance between the fixture 64 and the sealing plate 82 during insertion.