| 摘要 |
PROBLEM TO BE SOLVED: To conduct the inspection technique, a prevention safety technique, and a repairing technique of a structure in the rector of a nuclear power plant inexpensively by performing machining for applying a compression stress to the welded part of any or all of the equipments such as a jet pump riser pipe in a process for replacing a shroud. SOLUTION: When a reactor core shroud is exchanged, shot peening machining is performed to the welded part of an old shroud and a new shroud 2 on a work bench 7 installed at the bottom of the reactor while water at a reactor bottom part is drained and a means for shielding radiation is provided and water is injected into an annulus part. A shot supply tank 8 and a high-voltage air source are installed outside a pressure vessel 1, a carrying hose is passed through a CRD housing 5 or an ICM housing, and a shot that is accelerated by a high-voltage air is carried to a shot-peening nozzle, that is retained by a worker 11a. A suction hole for collecting a projection shot is installed around a nozzle in the head for shot peening, and the sucked shot returns to a supply device via a same path as the supply line and is used again. |
