| 摘要 |
Sleeves inserted in the coolant conductors of a steam generator of a nuclear-reactor plant are rolled by remotely controlled apparatus minimizing the time which personnel must spend within the radioactive environment of the channel head of the steam generator. A sleeve is rolled by a tube provided with rolls which are normally retracted and which, during a rolling operation, are extended into rolling engagement with the sleeve by a rotating tapered mandrel. The mandrel advances into the tube rotating the rolls while progressively increasing the pressure between the rolls and the sleeve. The sleeve is rolled near its upper end and also at its lower end in its region which is within the tube sheet by upper and lower rolling tools. The tube carrying the rolls is moved into the sleeve by a remotely controlled drive. The drive is a low voltage motor for the upper tool and a hydraulically driven piston for the lower tool. When the tube reaches its uppermost position in contact with the tube sheet or the end of the sleeve in the coolant conductor the mandrel is automatically actuated, responsive to the actuation of a switch to move into the tube to extend the rolls in the tube into progressively increasing pressure engagement with the sleeve and also to rotate as it moves into the tube. The translational drive for the mandrel is a low voltage electric motor for the upper tool and a pneumatically driven piston for the lower tool. The rotational drive for both tools is a hydraulic motor. That the desired upper rolling has been reached, is automatically determined by a thrust bearing on the mandrel which stops the advance of the mandrel into the tube at a proper diameter of the mandrel. The lower rolling is stopped responsive to the reactive torque of the hydraulic motor and may also be stopped by timing. In either case the three drives are reversed. The mandrel, in a direction opposite to its motion during insertion, is retracted, the rolls are removed from engagement with the sleeve and the tube is moved out of the sleeve. |
