METHOD FOR GROUP EXTRACTION OF STUDS OF FLANGE CONNECTIONS OF NUCLEAR POWER PLANTS BY MEANS OF A DEVICE FOR GROUP EXTRACTION OF STUDS OF FLANGE CONNECTIONS Russian patent published in 2022 - IPC B25B29/02 

FIELD: power engineering.

SUBSTANCE: group of inventions relates to a method for group extraction of studs of flange connections of nuclear power plants by means of a device for group extraction of studs of flange connections. The method involves installing a lid with mounting holes on the reactor or steam generator housing, screwing studs with mounting threads and technological threads through the mounting holes of the lid to a certain depth into the reactor housing, while spherical washers are installed on the mounting thread of the studs and crown nuts are screwed with a certain torque with the crown nut wrench, then on the technological thread of the studs the threaded rods are screwed all the way into the end of the studs, next, a support mechanism with a hydraulic power mechanism installed on it is installed on the lid through the threaded rods and crowned nut wrenches, and spherical washers are put on the outer thread of threaded rods and thrust nuts are screwed with a certain torque, absolute elongations of the size of the studs are monitored, after which the hydraulic power units are supplied with the pressure of the working fluid and produce group extraction of studs, fixing and bringing the values of the absolute elongations of the studs to the design value. After that, each hydraulic power unit is pressed with the necessary pressure, crown nuts with a certain torque are turned with crowned nut wrenches, pressure is relieved in the hydraulic power units, after which the device for group extraction of studs from the lid is dismantled. The control of the values of stud extraction is carried out by manually installing each reference pad with a control surface all the way to the base pad and the cylindrical surface of each threaded rod with horizontal alignment in the same plane with the end surfaces of the studs and fixed to the specified surfaces of the threaded rods by means of magnets, while measuring rods of pulse sensors are installed on the control surfaces of the reference pads with the necessary tension linear displacements of the measuring system for measuring the group extraction of studs, built on the basis of pulse counters from linear displacement sensors, a personal computer and a data output device, and the hydraulic power unit is performed containing a hydraulic cylinder with an immersion piston, through which the pistons of the hydraulic power unit are returned to their original position.

EFFECT: possibility of performing work in conditions of high crowding of flange connections, increasing the accuracy of measuring the elongation of studs, reducing the duration of the process of stud extraction by digitizing the control of stud elongation, reducing the number of maintenance personnel, reducing the absorbed dose of γ-radiation of the maintenance personnel during nuclear fuel recharge operations and repair of a nuclear reactor.

3 cl, 9 dwg