JPS58148996A - Control rod drive mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a control rod drive device for a boiling water nuclear reactor, and more particularly to a nine control rod drive device including a hydraulic control rod drive mechanism.

[Technical background of the invention and 0 questions, 1 point] In a boiling water nuclear reactor, a control rod drive mechanism is generally installed that is controlled by p-drive by driving water from a water pressure control unit, and the control rods are moved into the reactor. The output of the reactor is controlled by inserting and withdrawing the control rods.In order to ensure the safety of the operation, the hydraulic control unit is equipped with a control rod position detector. Controlled by a control salary position control device,
With this control rod position control device, the control rod position drift shape Im
(The control rod is not in a predetermined position, or the control rod is in a 1 meter position) and is designed to issue an alarm to the effect that an abnormality has occurred in the control rod drive device.

In addition, each control rod block consisting of multiple control rods (usually four control rods) is equipped with a Rondo block monitor equipped with a neutron detector to detect and monitor the neutron flux within the block. It's like getting.

A control rod drift condition occurs when the directional control valve in the hydraulic control unit fails or the latch mechanism in the control rod drive mechanism fails, making it impossible to control the reactor's normal output and causing local reactor output. There is a risk of a nuclear fuel failure accident. Therefore, conventionally, when wI@ indicating a drift state is issued and a local increase in neutron flux is detected, the operator rapidly pushes in the control rod that caused the abnormality (scram). This is designed to prevent the destruction of nuclear fuel due to local elevation of the core.

However, such a scram-like method by operators may cause serious danger if the response to abnormal conditions is delayed or warnings are overlooked. (9) It is necessary to have operators on standby at all times, which is not desirable from a labor management perspective.

[Purpose of the invention]

The present invention is made by layering these points.
When a control rod drifts and a local increase in neutron flux occurs, the control rod is automatically scrammed and nuclear fuel destruction accidents that can occur due to abnormal control rod withdrawal can be prevented. The purpose is to provide a control rod drive device.

[Summary of the invention]

The present invention controls control rod scram water pressure using a control rod drift state detection signal issued from a control rod position control device and a control rod withdrawal prevention signal issued from a travel time rond block monitor when neutron flux locally increases. The control rod scram is generated and the control rods in the shifted gear are automatically scrammed by this control rod scram water pressure.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to one drawing.

FIG. 1 is a system diagram showing an embodiment of a control system according to the present invention. In the figure, reference numeral 11 denotes a control rod drive mechanism, and the control rod drive mechanism 11 has an outer tube 13 which has an elongated cylindrical shape and is attached to the bottom of the reactor pressure vessel 12. A piston tube 14 is arranged, and an index tube 16 is arranged concentrically between the outer tube 13 and the piston tube 14 and has a drive piston 15 fixed to its lower end. The lower ends of the mitai 17 are connected. Reference numeral 18 is a rounded latch mechanism that holds the restraint 17 in place. A push-in piston chamber 19 is formed between the drive piston 15 and the piston/tube 14, and an insertion drive water nozzle is inserted into this insertion-side piston chamber 19. Further, a pull-out side piston chamber 21 is formed inside the piston/tube 14 and the index tube 16, and a pull-out sliding water nozzle a is inserted into this pull-out side piston chamber 21.

The reference numeral is a water pressure control unit that supplies driving water to the control rod drive mechanism 11, and is equipped with a control valve and a scram water pressure source. The control valves include four directional control valves 2 disposed in the middle of piping connecting the drive water source 6 and the control rod drive mechanism 11.
6 m + 26 b * 26 o H26&,
It consists of nine scram inlets arranged on the exit side of the two-way water pressure pipe and a scram outlet valve line arranged on the west inlet side of the scram drainage destination. The insertion drive water nozzle addition and drive water source 6 are connected to the insertion side piping (supply) and drive water piping 31 through K, and the extraction drive water nozzle 22. ! : Driving water#
δ is the contact i between the piping blade on the extraction side and the drive water piping 31.
has been done. Well, the middle of the extraction side pipe 32 is branched and connected to the scram drainage destination 4 by the scram drainage pipe 33, and the cooling water main is connected to the cooling water pipe 35 in the middle of the insertion side pipe I.
It is connected to. A scram water source 37 is connected to the scram water pressure th124 by a scram drainage pipe 36, and the outlet side for the meta 2 m water pressure # is connected to the middle of the inlet and extension side piping (source) through the scram inlet pipe 38. nine,
The piping that connects the insertion side piping I and the withdrawal side piping.

It is connected to the driving water drainage piping by a driving water drainage piping (G).

A control rod position detector 42 for detecting the position of the control rod 17 is inserted into the control body sliding mechanism 11, and a control rod position signal (i,
The signal line 43 sends it to the control rod position controller 41 where it is converted into a control ring position signal, and this drive signal is sent via the signal line 44 to the water pressure? l] lI iat+units) 23. As a result, the control valve in the water pressure control unit 23 is controlled to open and close, and the drive of the control rod 17 to the desired position is controlled. Further, the control device 41 controls the control '4I.
Detects the drift condition of 7, Drift) 1! Each block of control rods, which is made up of a plurality of control rods and is configured to emit a drift detection signal as well as a drift detection signal, is equipped with a rod block monitor 45 equipped with a neutron flux detector that detects the neutron flux within the block. is installed to monitor the neutron flux. Further, the Rondo block monitor 45 is designed to detect a local increase in the neutron flux within the plotter and issue a signal to prevent control rod withdrawal. The control rod position control device 41 and the rod block monitor 45 are connected to each other by signals @46.47, and the control rod position control device 41 is connected to the signal line 46.
Based on this command, the position of the selected control rod to be monitored is determined by the rod block monitor 45KtW command, and rod block monitoring is performed by the rod plotter monitor 45, which monitors the block in which the selected control rod exists based on this command. , when a local increase in the neutron flux within the block is detected,
A control rod withdrawal prevention signal is sent to the control rod position controller by signal @47.

Next, the operation of this embodiment having such a configuration will be explained.For example, the direction control valve 26m, which is opened when supplying the driving water from the driving water #δ to the drawing driving water nozzle n, may be controlled due to the contamination of foreign matter, etc. Even though the rod withdrawal sequence is completed, if the control rod 17 becomes an open rod, it will fall further.
It becomes a foreshadowing that the whole story is drawn out. Such a drift state of the control rods 17 not only makes it impossible to operate the control rods, but also locally increases the thermal output of the reactor core near the control rods 17.

In addition, if the latch mechanism 18 fails due to some reason, 4. The control rod 17 becomes unstable and a drift condition occurs.

When such a drift-like part of the %fil m1ll rod occurs, a drift detection signal is issued from the control-position control device 41, and a control rod pull-out signal No. 18 is issued from the Rondo block monitor 45. , control rod position detector #L
41.

FIG. 2 is a diagram illustrating a situation in which the control rod is scrammed when such a drift condition occurs and the control rod is about to die. When the drift detection object signal and the control rod withdrawal prevention signal 51 are issued at the same time, one of these signals is transmitted to the control position electric control device 4I.
It is determined that the control rod 17 is in a dangerous drift soft line, and the control rod #1 is
The control signal & for scrumming 7 is issued. In response to this control rod scram request signal 53, a signal 55 is issued to open the scram inlet valve and the scram outlet valve in the hydraulic control unit, and the scram inlet and scram outlet valves are opened. I agree with this,
High-pressure stalum water from the scram water pressure pump enters the insertion side piston chamber 19 from the insertion driving water nozzle, and water in the withdrawal side piston chamber 4 is drained from the sliding water nozzle ρ to the scram drainage destination 29. From and k, a scram (rapid insertion) of control $17 is performed.

In addition, in this embodiment, the control rod position control device '41
A control salary reselection prevention bypass circuit is provided in the
When a drift state of a control rod is detected and a drift detection signal is issued, a control rod reselection inhibition command 57 is issued to prevent the operator from selecting another control rod. This prevents unnecessary scram requests for other control rods.

[The fruits of invention]

As explained above, according to the present invention, a dangerous drift condition of the control rod is detected, and only the soma rod can be automatically scrammed. Consequently, compared to the conventional method of only issuing a warning to operators, it is possible to respond to failures more quickly and to further improve the safety of the reactor.

In this example, the control rod scram request signal was used to open the scram population valve and scram exit valve of the hydraulic control unit, but other methods may also be used to scram the control rods. good. For example, if a control rod is disposed above the reactor core, the scram request signal may be used to pressure the control rod to fall naturally.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a control rod drive device according to the present invention, and FIG. 2 is a schematic circuit diagram showing a control rod scram function according to the present invention. 11... Control rod drive mechanism, 17... 1I711#, Ru... Water pressure control unit, 41... Control rod position control device, 45... Rondo block monitor. Applicant's agent Kiyoshi Inomata Procedural amendment April 1, 1980 Japan Patent Office JK official Shima 1) Haruki Tonoro Special Petition No. 31310 of 1981 2, Invention Name Control Rod Drive Device 3 Amendment Case Relationship with Patent applicant (307) *Kyoshibaura Electric Co., Ltd. (FI or 1 person) 1 Peng ■ - Correct the 8th cabinet as shown in the attached sheet. Specification/Title of the Invention Control rod position control device for controlling a hydraulic control unit that supplies driving water to a rod drive mechanism; In a control rod drive device equipped with a rod block monitor that detects neutron flux, the control rod position side U*W detects the drift pattern III of the control rod and issues a drift detection signal, and the rod block monitor When the neutron flux locally increases in the block, a control rod extension/extraction prevention signal is issued, and a control rod scram cost request signal is issued based on the drift detection signal and the control Ie withdrawal inhibition signal, and this control rod scram is A control rod drive device characterized in that a control rod that enters a single-distribution drift state is automatically scrammed by a request signal. Claim 3: Detailed Description of the Invention [Technical Field of the Invention] The control i41 rod scram request signal is input to the water pressure control unit and the scram population valve and scram outlet valve of the water pressure control unit are opened. ] The present invention relates to a control rod drive device κ for a boiling water reactor, and a control rod drive l#cr equipped with a hydraulic control rod drive mechanism.
Regarding t. [Technical background of the invention and its problems] In a boiling water nuclear reactor, a control rod drive@Sakaki is generally installed that is driven and controlled by driving water from a water pressure control unit, and the control rod is inserted into the reactor. The output of the reactor is controlled by the withdrawal operation. In order to ensure the safety of such control rod drive 1i[K, the hydraulic control unit is equipped with a control rod position detector and controlled by a control rod position control device. The control device detects the control rod drift condition (the control rod is not in the specified position or the control rod position is fluctuating I1) and issues an alarm that an abnormality has occurred in the control rod drive device. It is being done. In addition, II number of neutron flux detection a! Each block of control rods consists of (usually t neutron flux detectors). A rod block monitor is installed to monitor control rod withdrawal based on the signal from the neutron detector, and the neutron flux inside the block can be detected and monitored. - The control rod drift status is monitored by the hydraulic control unit. In the event of a mechanical failure, such as a failure of the directional control valve in the control rod or a failure of the latch mechanism in the control I1 rod movement mechanism, the Rondo block monitor cannot electrically prevent the control rod from driving. The reactor's normal power output makes it impossible to make koji. There is a risk that the reactor power will locally increase and a Vk fuel failure accident will occur. For this reason, conventionally, when an alarm indicating control rod drift is issued and a local increase in neutron flux is detected, an operator goes to the installation location of the hydraulic control unit and either repairs the fault or removes the control rod. By carefully controlling the drive device and hydraulic control unit), we are working to prevent the control rod from driving. However, with such a method that requires on-site operations by operators, serious dangers may arise if the response to an abnormal situation is incorrect or if a warning is overlooked. Also, it is not desirable from a labor management perspective since it is necessary to have operators on standby at all times. [Object of the Invention] The present invention has been made taking these points into consideration.
When a control rod drift occurs and a local increase in neutron flux occurs, the control rod is automatically scrammed to prevent nuclear fuel destruction accidents caused by abnormal control rod withdrawal. The purpose of this invention is to provide a control rod drive device that uses [Summary of the Invention] The present invention provides a control rod drift state detection signal emitted from a control rod position control device, and a control rod withdrawal prevention signal emitted from a rad boot monitor when neutron flux locally increases. A control rod scram signal is generated from K, and the control rods in the seated state are automatically scrammed by this control rod scram signal. [Invention! II! Embodiment] An embodiment of the present invention will be described below with reference to one drawing. FIG. 7 is a system diagram showing an embodiment of a control rod drive device according to the present invention. In FIG. The next actuator is attached to the bottom of the reactor pressure vessel/J, the piston tube array is arranged concentrically within this outer tube/3, and the outer tube/J and the piston tube array are concentrically arranged at the intersection of the outer tube/J and the piston tube array. an index tube/4 arranged in the form of a drive piston 15 fixed to the lower end
and a control rod/4 at the upper end of the index tube/4.
The lower ends of 7 are connected. This is a hook mechanism for holding the control rod 17 in a predetermined position. An insertion piston chamber is formed between the drive piston 15 and the piston tube group, and an insertion drive water nozzle is inserted into the insertion side piston 11/l. Further, a pull-out side piston chamber 1 is formed inside the piston tube group and the index tube 11, and a pull-out driving water nozzle is inserted into this pull-out side piston chamber 1. Reference numeral n designates a hydraulic opening unit for supplying drive water to the control rod drive mechanism/l, and is equipped with a control valve and a scram water source. The control valves are three directional control valves A installed in the middle of the piping connecting the drive water source and the control rod drive mechanism/l.
m, mb, mc, md. It consists of a scram inlet valve core disposed at the outlet of the scram water pressure source and a scram outlet valve d disposed at the artificial glue of the scram drainage destination 9. The insertion drive water nozzle J and the drive water source are the insertion side piping X and the drive water piping J/
The drawing drive water nozzle and the drive water source are connected by the pull #LIiI pipe J and the drive water pipe 31. In addition, the middle of the 3 piping on the extraction side is branched to the scram drainage destination code like the scram drainage piping JJK.
1IIIN, and there is a cooling water source 3 in the middle of the insertion side piping JO.
# is connected to the cooling water pipe uK). For the scram water pressure source, the scram water source 3 is connected to the scram filling water pipe J4.
7 is connected, and the outlet of the scram water source outlet is connected to the middle of the insertion pipe 30 by the scram inlet pipe Jt. Also. The piping that connects the insertion hook piping 30 and the three extraction side piping is as follows:
It is branched and connected to a drive water drainage destination VO through a drive water drainage pipe 39. Control rod position detectors 4/ and 7 are inserted into the control rod drive machine #Ij// to detect the position of the control rod/7, and the control rod position detectors 4/ and 7 are inserted into the control rod drive machine #Ij// to detect the position of the control rod/7. The position signal is sent to the control rod position controller lI/ by the signal @p3 and converted into a control rod drive signal, and this drive signal is sent to the hydraulic control unit 7 by the signal 111. As a result, the control valve in the water pressure control unit n is controlled to open or close, thereby controlling the drive of the control rod/7 to a predetermined position. 9. The control rod 1 control device q/ is adapted to detect the drift state of the control rod 141/7 and issue a drift alarm as well as a drift detection signal. Each block of the control rod, which is composed of a plurality of control rods, is equipped with a Rondo block monitor lIj equipped with a neutron east detection device that detects the neutron flux within the block, so that the neutron flux can be monitored. is being done. (9) Rod block monitor) 4Ilj is designed to detect when the neutron flux within the block locally increases, and to issue a signal to prevent control rod withdrawal. The control rod position control device and the rod plotter monitor Hiroj send each other a signal @H, 1171.
1C is connected, and the control rod position controller is connected to the signal, 1
414>, the position of the selected control rod to be monitored is commanded to the rod monitor 0, and the cI controller monitors the block in which the selected control rod exists based on this command. . When Radblock Electric Co., Ltd. detects a local increase in neutron flux within the block, a control rod withdrawal prevention signal is activated! It is sent to the P control rod position control device DA/ by the I reference. Next, the operation of this embodiment, which has a unique configuration, will be explained. For example, if the directional control valve 1, which is opened when supplying drive water from the drive water source to the pull-out drive water nozzle, remains open even though the control rod pull-out sequence X has ended due to foreign matter being mixed in. , the control rod/ri is further lowered and becomes fully withdrawn. Such a drift state of the control rod 17 is dangerous because it simply makes the control rod inoperable, and locally increases the thermal output of the core near the control rod/7. Further, if the latch mechanism /l fails for some reason, the control rod 17 will be in an unstable state and a drift state will occur. When such a drift state of the control rods occurs, a drift detection signal is issued from the control rod position control device G/, a control rod withdrawal prevention signal is issued from the rod plotter monitor 3, and the control 141 It is manually inputted to the rod position control device 4I/. FIG. 1 shows a logic circuit that scrams the control rods when such a drift condition occurs. When the drift detection signal 50 and the control rod withdrawal prevention signal S/ are issued at the same time, these two signals are input into the AND logic circuit 5λ in the control rod position control device IIl, and the control rod 41117
It is determined that control rod 7 is in a dangerous drift condition, and a control rod scram request signal, frequent 3, is issued to scram that control rod/7. This control rod scram cost request signal SJ
Yes, a signal to open the scram population valve and scram outlet valve in the water pressure control unit! $, j
j is issued and scram outlet valve 27 and scram outlet valve d are opened. This is Kyop, high-pressure stalum water from the Sufu2mu water pressure source is inserted from the divinely driven water nozzle - piston wealth I! By draining the water in the piston chamber U from the extraction drive water nozzle to the scram drainage destination, a scram (rapid insertion) of the control rod/ri is achieved and no stone is removed. [Effects of the Invention] As explained above. Thus, according to the present invention, a dangerous drift condition of a control rod is detected and only that control rod can be dynamically scrammed. Therefore, compared to the conventional method of only issuing a warning to operators, it is possible to respond to failures more quickly and to further improve the safety of the sub-reactor. In this embodiment, the control rod status request signal is used to open the scram inlet valve and scram exit valve of the hydraulic opening unit, but to scram the control rods, other methods are used. 4 Good. For example, if a control rod is installed above the reactor core, the control rod may be caused to fall naturally in response to a scram cost request signal. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 7 is a system diagram showing a control rod drive device according to the present invention, and FIG. 1 is a logic circuit diagram showing a control rod scram function according to the present invention. // Control rod drive mechanism, 17... Control rod, J... Water pressure control unit, D/... Control i41 rod position lid control koji device, t
I3 Rod plotter electrician.

Claims (1)

[Claims] 1. A control rod position control device that controls a hydraulic control unit that supplies drive water to a control rod drive mechanism, and a Rondo block monitor that detects neutron flux in each block of the control rods. In the control rod drive device, the control rod position control device detects the drift state of the control rods and issues a drift detection signal, and the rod glock monitor detects the drift state of the control rods and issues a drift detection signal. A control rod withdrawal prevention signal is issued, and a control rod scram request signal is issued based on the drift detection signal and the control rod withdrawal prevention signal, and this control rod scram request signal causes the draft heel to be Control 41 that makes certain control rods automatically scrammed! Drive electrical equipment. 2. The control rod drive device according to claim 1, wherein the control scram request signal is input to a hydraulic control unit to open a scram inlet valve and a scram outlet valve of the hydraulic control unit.