Rod drop system and method of control rod driving mechanism

Abstract

The invention relates to a rod drop system and a method of a control rod driving mechanism. The rod drop system comprises a sleeve, a spring, a spiral transmission mechanism and two friction plates, wherein a separation plate which is used for separating an inner cavity into an upper section and a lower section along the length extension direction is arranged on the inner wall of the sleeve; a limiting sleeve which is positioned above the separation plate is arranged in the inner cavity of the sleeve; the spiral transmission mechanism comprises a rotary friction plate which is connected to the outer edge of a guide rod through threads and can move vertically along with the guide rod; one of the two friction plates is fixedly connected to the upper surface of the separation plate, and the other friction plate is fixedly connected to the lower surface of the rotary friction plate and is opposite to the friction plate which is fixedly connected to the upper surface of the separation plate. According to the system and the method, during the drop of a control rod, the effects of effective buffering and complete damping are achieved in sequence, the damage to the control rod driving mechanism is avoided, and the risks of breakage of a chain, bending or damage of a chain wheel shaft and the like are reduced.

Description

technical field [0001] The invention relates to a nuclear reactor control rod driving mechanism system engineering equipment, in particular to a rod dropping system and method of the control rod driving mechanism. Background technique [0002] As shown in Figure 1(a)-(c), the buffer damper of the control rod drive mechanism of the molten salt reactor in Oak Ridge includes: chain 1', chain pin 2', buffer damping rod 3', buffer spring 4 ', steel ball return spring 5' and steel ball 6'; the principle is to convert the impact energy through the buffer spring 4', and add a throttle (not shown) in front of the flowing steel ball 6' for damping , specifically, its working process includes: start the drop rod; drop the control rod 7' until it completely covers the activation area; compress the buffer spring 4', and the steel ball 6' enters the throttle port; the steel ball return spring 5' is released, the steel ball The ball 6' flows out of the orifice; the above two steps are car...

AI Technical Summary

Problems solved by technology

The buffer only converts the impact energy without reducing the speed, while the damping reduces the speed. When the energy is not fully absorbed, the control rod must rebound. The first damping time is long, and the stroke of the buffer damping is large and the channel is long; after the falling rod covers the active area Performing buffer damping at the same time will prolong the drop time. This is because the buffer damping and damping time will add up at the same time, and the buffer damping stroke will be increased, so the length of the buffer damping channel needs to be increased, because if the channel length is reduced, then Buffer damping must be performed in advance, which will inevitably prolong the time of covering the active area, and the control rod must cover the active area within the specified time. The number of subs may increase geometrically per second, resulting in a nuclear hazard. Therefore, the active area must be covered within a specified time

In addition, the length of the poisonous object of the control rod can only be increased to achieve the purpose of completely covering the active area before and after buffering and damping

Therefore, although the falling speed of the rods is too fast when the reactor is high, this method can be used, but it will increase the length of the buffer damping channel and the length of the control rod poison

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