| 摘要 |
PURPOSE:To prevent the generation of vibration caused by wear and to improve the reliability and the handlability by providing a whole mast so as to be freely movable in the radial direction of an RPV on a carriage, and also, constituting the device so that an arm ascends and descends along the lower mast. CONSTITUTION:When the upper and the lower masts 16, 18 are allowed to descend vertically, a mast guide 15 and the masts 16, 18 are fixed to a mast supporting base 26 of a carriage 14 so that a head 20 and an arm 19 do not abut on a feed water sparger 7 and a reactor core spray inner tube 8 in an RPV 1, and thereafter, the mast 16 is allowed to descend until a guide roller 44 of the lower end part of the mast 18 approaches the upper shroud 6. Subsequently, by moving a supporting base 26 in the radial outside direction of the RPV 1, the masts 16, 18 are allowed to approach the wall surface of the RPV 1, the arm 19 and the head 20 are crept in right under the sparger 7 and the inner tube 8, and the mast 18 is allowed to descend until the roller 44 comes into contact with the inner wall. While the head 20 is scanning, only the arm 19 moves, and the mast 18 remains still. In such a way, play caused by wear of the mast supporting part is obviated. |
