Shield main pump main bolt dismounting and mounting tool and method

Abstract

The invention discloses a shield main pump main bolt dismounting and mounting tool and method and belongs to the technical field of nuclear power plant shield main pump maintaining. The shield main pump main bolt dismounting and mounting tool comprises a supporting piece used for being mounted on a main flange of a shield main pump, a main bolt rotating assembly used for being mounted below the supporting piece to enable a main bolt to be upwards screwed out from a threaded hole of a pump shell of the main pump or downwards screwed in, and a main bolt hoisting assembly used for being mounted above the supporting piece to guide the screwed-out main bolt out of the shield main pump in a hung mode or guide the to-be-screwed-in main bolt into the shield main pump in a hung mode. The shield main pump main bolt dismounting and mounting method is executed through the shield main pump main bolt dismounting and mounting tool. Before a shield main pump mounting trolley reaches the designated position, the dismounting and mounting functions of the shield main pump main bolt can be achieved, the process time of bulk material dismounting and shield main pump mounting trolley assembly is saved,the time for key path overhauling by the main pump is shortened, and the total radiation dose of a maintainer is lowered.

Description

technical field [0001] The invention relates to the technical field of maintenance of shielded main pumps of nuclear power plants, in particular to a tool for disassembling and assembling main bolts of shielded main pumps and a method for disassembling and assembling them. Background technique [0002] After the nuclear power plant has been in operation for a long time, the possibility of problems with the thrust bearing and shielding sleeve of the shielded reactor coolant pump (hereinafter referred to as the shielded main pump) gradually increases, and the process of replacing and overhauling the main pump in a radioactive environment is planned in advance And the development of special tools is necessary. The shielded main pump casing is welded to the bottom of the steam generator. The shielded main pump is installed upside down on the pump casing at the bottom of the steam generator through 24 main bolts. If the shielded main pump needs to be disassembled, the main bolts ...

AI Technical Summary

Problems solved by technology

Through the comprehensive analysis of the field conditions of the evaporator compartment, the connection method between the shielded main pump and the pump casing, and the disassembly and assembly process of the main bolts of the shielded main pump, the main factors restricting the disassembly of the main bolts of the shielded main pump are as follows: 1. Westinghouse designed the shielded main pump The main bolt removal process is based on the prerequisite that the shielded main pump installation trolley is in place, but the shielded main pump installation trolley can only be lifted to the steam generator chamber after the bulk materials in the evaporator compartment are removed. The disassembly and assembly of the main bolts will restrict the critical path of the main pump maintenance, greatly increase the time of the critical path, and increase the total radiation dose of maintenance personnel; 2. Multiple inspections of the elongation of the main bolts of the shielded main pump during the service life will involve disassembly and assembly of the main bolts Works, but with shielded main pump installation trolley access to main bolts requires removal of bulk material in evaporator compartment

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