| 摘要 |
In order to reduce the number of lifts which are required to remove the various equipment normally disposed above the reactor pressure vessel and to make way for refuelling or regular maintenance, the control rod element drive mechanisms are completely enclosed within a cylindrical enclosure which is attached to the head of the pressure vessel. The top of the cylindrical enclosure is closed with a cap-like member which acts as both a missile shield and a head area cable tray. The missile shield, the cylindrical enclosure, the control rod drive mechanisms and the pressure vessel head, are connected to form an integral unit which can be removed in a single lift. Cable trays are pivotally supported on a wall of a building to establish a bridge between the building and the head area cable array and to establish a connection with the control element drive mechanism cables. During lifting, the control element drive mechanism cables are disconnected and the pivotal bridge trays are swung out of the way. During normal operation, the cylindrical enclosure guides a flow of cooling air over the control rod drive mechanisms. |
