High-precision driving mechanism for nuclear reactor control rod

Abstract

A high-precision driving mechanism for a nuclear reactor control rod is characterized in that the two ends of a lead screw of a ball screw pair are installed on supporting columns on the two sides ofa base through bearings, the left end of the lead screw is connected with an output shaft of a motor through a coupler, and an electromagnetic attraction mechanism is fixedly installed at the top of anut of the ball screw pair; a linear sliding rail made of stainless steel is further installed at the top of the supporting column, the electromagnetic attraction mechanism is opposite to a magneticsliding block of the linear sliding rail, the right end of the magnetic sliding block is connected with the head end of a steel rope, and the tail end of the steel rope is connected with the nuclear reactor control rod after bypassing the fixed pulley; the motor and the electromagnetic pull-in mechanism are electrically connected with a control and detection device of the nuclear reactor. The driving mechanism can perform high-precision and low-time-lag control and adjustment on the output power of the nuclear reactor; accident emergency shutdown can be reliably realized, the structure is simple, the processing and assembling precision is low, and the reliability is high; the operation efficiency of the nuclear reactor is improved, and the operation safety of the nuclear reactor is ensured.

Description

technical field [0001] The invention relates to a drive mechanism for control rods of a nuclear reactor. Background technique [0002] A nuclear reactor is a device that enables the chain reaction of nuclear fission to continue in a controlled manner. Changing the number of neutrons in the reactor can change the severity of the nuclear reaction, thereby changing the power of the reactor. The control rods are made of a material that strongly absorbs neutrons. It is arranged in the core and interspersed with fuel assemblies. The number and speed of neutron absorption can be changed through the lifting and lowering of the control rods, thereby effectively controlling the reaction speed of the reactor: when the reactor reaction is strong, the control rods are inserted deeper to increase the number of neutrons absorbed, chain The reaction slows down, and the power of the reactor decreases; when the control rods are fully inserted, the fission chain reaction can be prevented, a...

AI Technical Summary

Problems solved by technology

[0009] This kind of magnetic lifting type control rod driving mechanism has the following disadvantages: 1. Each action requires three groups of electromagnetic coils and magnets, and two groups of claws to cooperate precisely in time and space and switch continuously; its control method is cumbersome and difficult, and its The structure is complex, and the precision of parts processing and assembly is very high

2. The time of each lifting and lowering is determined by the lifting time of the magnet attraction and the action time of the hook claw. It is almost impossible to adjust. The action time is fixed, and the action time is difficult to be less than 2s. The time lag is long, and it is difficult to make timely adjustments according to the actual situation of the nuclear reactor.

3. Each lifting and lowering is step-by-step adjustment with a step distance (10mm), and its adjustment accuracy is low, which cannot meet the precise adjustment of nuclear reactor power

4. The transmission shaft and the control rod do impact step movement, the grooves on the claw mechanism and the transmission shaft wear a lot, and the reliability is poor

Wear and tear of hooks and grooves or entry of foreign matter may cause the hooks to fail to move effectively, and even cause emergency shutdown, the control rods cannot drop quickly, resulting in failure of emergency shutdown, which poses a serious safety hazard

5. When the driving mechanism is running, the electromagnetic coil is repeatedly energized to generate resistance heat. At the same time, the entire driving mechanism is close to the nuclear reactor. The thermal radiation of the high-temperature water in the primary circuit of the nuclear reactor further increases the temperature rise of the electromagnetic coil, making the insulation performance of the electromagnetic coil worse. , which also makes the driving mechanism poor in reliability and short in life

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