RU2057375C1 - Device for shutting down gas-cooled nuclear reactor - Google Patents

Abstract

FIELD: nuclear engineering. SUBSTANCE: device has vessel 1 filled with loose neutron-absorbing material 2 and placed above core 3. Vessel 1 communicates with one or more channels 4 passing through side deflector 5 from top downwards to uptake piping 6 and communicating with the latter through header 7 which communicates through its bottom part with air transport device through discharging device 10. Each channel 4 is connected to header 7 through discharging device 9. Header 7 has volume equal to that of loose neutron-absorbing material discharged from channel 4 within one cycle. Discharging device 9 and 10 are connected to mechanism changing over air transport from channel to header. EFFECT: improved design. 1 dwg

Description

 The invention relates to nuclear engineering and can be used in gas-cooled nuclear reactors with a bulk core of spherical fuel elements.

 Known devices for stopping a gas-cooled nuclear reactor with a bulk core from spherical bodies by introducing absorbing material in the form of small diameter balls into the channels of the side reflector (German patent N 3242760, class G 21 C 7/22, from 05.24.84 [1]).

 In these devices, bulk neutron-absorbing material is placed in containers above the side reflector of the active zone. If necessary, the absorbing balls under their own weight enter the channels of the side reflector and stop the reactor. In the lower part, the channels of the side reflector are equipped with exhaust devices for small absorbing balls, to which pipelines are attached to output these balls.

 A device for turning off a high-temperature reactor is also known [2]. In this device, balls are poured under the action of gravity from containers placed above the core into the channels of the side reflector. Balls as necessary, for example, when starting the reactor are removed from the channels through special tubes or blown out. By adjusting the blower power used to transport the balls, it is ensured that only one channel is emptied at a time.

 When equipping a nuclear reactor with this device, in the event of a malfunction in the pneumatic lifting means, unauthorized emptying of several channels or sequential unauthorized unloading of all channels can occur, which can lead to spontaneous start-up of the reactor.

 In this device, the channels are emptied to the entire height, and from the point of view of reactor physics, it is most preferable to emit the channels in small portions in order so that the level of neutron-absorbing material in the channels decreases uniformly when the reactor is started, which eliminates the distortion of the neutron-physical characteristics of the reactor in height and radius of the core.

 The objective of the invention is to eliminate the possibility of unauthorized emptying of the channels, leading to spontaneous start-up of the reactor.

 The problem is solved in that in the known device for stopping a gas-cooled nuclear reactor containing a container with bulk neutron-absorbing material placed above the active zone and connected to one or more channels passing through the side reflector from top to bottom and equipped with unloading devices, and a lifting pipe with a device pneumotransportation of neutron-absorbing material from the channels, the unloading device of each channel is connected to a lifting pipeline through a common minutes for all channels manifold whose volume is less than the total volume of particulate neutron-absorbing material contained in one channel, the apparatus is provided with a pneumatic switching device from the channel to the collector.

 This embodiment of the shutdown device for a gas-cooled nuclear reactor eliminates unauthorized emptying of the channels, which can lead to spontaneous start-up of the reactor, since when the pneumatic conveying device is connected to the channel unloading device, the neutron-absorbing material is unloaded from the channel into the collector, while the volume of the neutron-absorbing material being unloaded from the channel material can not be more than the volume of the collector. After that, the pneumatic conveying device is connected by means of a pneumatic conveying switching mechanism to the unloading device of the collector and the neutron-absorbing material from the collector is unloaded into a container located above the core. To unload the next portion of neutron-absorbing material from the channel, the pneumatic conveying device is connected via the pneumatic conveying switching mechanism to the channel unloading device. This increases the reliability of the device to stop the gas-cooled nuclear reactor.

 The drawing schematically shows a General view of the reactor with a device for stopping it, longitudinal section.

 A device for stopping a gas-cooled nuclear reactor contains a container 1 with a loose neutron-absorbing material 2 in the form of small diameter balls placed above the active zone 3 and connected to one or more (in the drawing with two) channels 4 passing through the side reflector 5 from top to bottom to the lifting pipeline 6 and communicating with it through the collector 7. If necessary, the gates 1 open under the action of the actuators 8 and the gates open and neutron-absorbing material 2 enters the channels 4 under the action of gravity. The channels 4 One to the manifold 7 through the unloading apparatus 9. The manifold 7 through its lower part a discharge device 10 is connected to the lifting conduit 6 which at its upper part is connected with the container 1.

 Unloading devices 9 of the channels 4 and the unloading device 10 of the collector 7 are connected to the pneumatic conveying device via the pneumatic conveying mechanism 11, which connects either the unloading device 9 of one of the channels 4 or the unloading device 10 of the collector 7 to the pneumatic conveying device.

 During normal operation of the reactor, the neutron-absorbing material 2 is located in the tank 1, located above the active zone 3. If necessary, stop the reactor in the tank 1 under the action of the actuators 8, the gates open and the neutron-absorbing material 2 under the influence of gravity enters the channels 4 in the side reflector 5 and fills them full height. A reliable shutdown of the reactor occurs for any period.

 When starting the reactor, it is necessary to remove the neutron-absorbing material 2 from the channels 4. This is carried out as follows. The pneumatic transport switching mechanism 11 is set to the “Channel N” position, where N is the number of the channel from which a predetermined portion of the neutron-absorbing material is to be unloaded, thereby the discharge device 9 of the corresponding channel 4 is connected to the pneumatic transport device and the transporting gas supplies the neutron-absorbing material from the channel 4 to the collector 7 filling it up completely. The collector 7 is made in volume equal to a given portion discharged from the channel in one cycle. After that, the switching mechanism of the pneumatic transport 11 is transferred to the "Collector" position, thereby the unloading device 10 of the collector 7 is connected to the pneumatic conveying device and the transporting gas moves the neutron-absorbing material from the collector 7 through the lifting pipe 6 to the tank 1.

 Thus, the neutron-absorbing material is unloaded alternately from other channels. Such cycles of sequential batch unloading of the neutron-absorbing material from the channels are repeated until they are completely or partially emptied, depending on the operating mode of the reactor or the scheme for unloading the neutron-absorbing material from the channels.

Claims (1)

 DEVICE FOR STOPPING A GAS-COOLED NUCLEAR REACTOR, containing a container with bulk neutron-absorbing material placed above the active zone and connected to one or more channels passing through the side reflector from top to bottom and equipped with unloading devices, and a lifting pipeline with a pneumatic transport device for neutron-absorbing material from the channels that the unloading device of each channel is connected to the lifting pipeline through a collector common to all channels , Which amounts to a part of the volume of one channel, and a pneumatic device is provided with a switching device on the channel to the collector.