A large-scale shielded main pump main bolt tensioning device and tensioning method

Abstract

The invention relates to the technical field of maintenance of a shielded main pump of a nuclear power plant, in particular to a tensioning device and a stretching method for a main bolt of a large shielded main pump. A main bolt tensioning device for a large-scale shielded main pump, including a tensioning mechanism, a tensioning mechanism disassembly assembly, and a pneumatic control system; the tensioning mechanism includes a piston cylinder; a bridge, connected to the axial bottom end of the piston cylinder and The bottom is provided with an open slot; the axial bottom end of the stretch rod is provided with a threaded connection hole facing the open slot, and the axial top end is provided with a limit installation slot; the piston is arranged inside the piston cylinder and connected with the pull The extension rod is socketed; the oil inlet pipe, one nozzle is connected with the hydraulic pump through a high-pressure hose, and the other nozzle is connected with the cavity of the piston cylinder. The main bolt tensioning device and stretching method of the present application can safely, reliably and conveniently realize the tensioning and tightening function of the main bolt of the shielded main pump, shorten the installation time of the shielded main pump, and ensure rapid response in case of failure of the shielded main pump, The time for unplanned shutdown of nuclear power plants is shortened.

Description

technical field [0001] The invention relates to the technical field of maintenance of a shielded main pump of a nuclear power plant, in particular to a tensioning device and a stretching method for a main bolt of a large shielded main pump. Background technique [0002] The shielded reactor coolant pump (hereinafter referred to as shielded main pump) pump casing is welded to the bottom head of the steam generator. The shielded main pump is installed on the pump casing upside down through 24 main bolts, and the main bolts are heated by the main bolt heater. Stretching and tightening, the overall installation of the shielded main pump involves repeated thermal stretching of the main bolts. Through the comprehensive analysis of the field conditions of the evaporator compartment, the connection mode between the shielded main pump and the pump casing, and the thermal stretching process of the main bolt of the shielded main pump, the following problems exist in the main bolt therm...

AI Technical Summary

Problems solved by technology

Although the site considers to use the fan to continuously blow air to accelerate the cooling of the main bolt after heating, but part of the heating section of the main bolt is assembled in the main flange, and this part cannot be directly cooled, and it is difficult to achieve a significant cooling effect

Due to the long time required for the heating and fastening process of the main bolts, it affects the critical path of overhaul or unplanned outage time, and the consideration of the 60-year design life of nuclear power units has a great impact on the economic benefits of nuclear power plants

[0004] 2. The elongation of the main bolts is not easy to control: due to the difference in the quality of the heating rods of the bolt heaters, the different operating methods of the operators, and the influence of each group of main bolts on other main bolts and main flanges after heating, the main The elongation of the bolts is not easy to control, so there may be some differences in the pre-tightening force of each main bolt, and the elongation of the main bolts needs to be adjusted repeatedly to meet the requirements

[0005] To sum up, the main bolts of the shielded main pump are disassembled by means of bolt heater thermal tightening, which has defects such as time-consuming disassembly and assembly of the main bolts and difficult control

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