JPS62220896A - Control-rod drive hydraulic device - 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] [Object of the Invention] (Industrial Application Field) The present invention relates to a control rod drive II used in a boiling water reactor.
This invention relates to an III control rod drive hydraulic system that drives a control rod system.

(Prior Art) In a boiling water reactor, as shown in FIG. 2, a large number of control rod drive mechanisms 2 are attached to a lower head plate 1 of a reactor pressure vessel. The control rod drive mechanism (CRD) 2 employs a hydraulically driven piston system. By supplying driving water to the lower or upper surface of this hydraulically driven piston 3, the piston 3 can be moved up and down! , II control rod (CD) 4 is inserted between or pulled out from a set of four fuel assemblies (not shown), thereby controlling the output of the nuclear reactor.

In addition, in the event of a reactor abnormality, a water pressure
Open the scram inlet valve 6 and scram outlet valve 7 of the till unit 5. The high-pressure driving water stored in the accumulator 8 is supplied to the lower surface of the piston 3 of the control rod drive mechanism 2 via the insertion pipe 9, while the return water on the upper surface side of the piston 3 is supplied to the scram discharge equipment via the usage pipe 10. 11
is discharged to.

As a result, the control rod drive mechanism 2 is configured to perform a reliable scram operation and ensure the safety of the reactor.

Further, the scram inlet valve 6 and the scram outlet valve 7 use air-operated valve structures such as air-operated diaphragm valves, and these valves are opened and closed by operating air pressure. This operating air pressure is applied to an air supply piping 12 such as an instrument air piping system (IA system) led from an air source (not shown),
Air header piping 13, air piping 14, three-way solenoid valve 15,
The scram inlet valve 6 and the scram outlet valve 7 are supplied via an air connection line 16.

The three-way solenoid valve 15 is excited during normal reactor operation and supplies operating air pressure to the scram inlet valve 6 and the scram outlet valve 7, completely closing these valves. Further, during a scram due to reactor abnormality, the demagnetization is performed, the inside of the air connection pipe 16 is communicated with the atmosphere, the supply of operating air pressure is stopped, and the scram inlet valve 6 and the scram outlet valve 7 are fully opened.

(Problems to be Solved by the Invention) As described above, the three-way solenoid valve 15 of the conventional control rod-driven hydraulic system receives the operating air pressure used to open and close the scram inlet valve 6 and the scram outlet valve 7 from the air source. The air is supplied by a guided air supply pipe 12, an air header pipe 13, and an air pipe 14.

However, since the air supply pipe 12 is led from a distant air source, the length of the pipe is very long, for example, 100 m or more. On the other hand, since the air header piping 13 is branched from the air supply piping 12 and arranged above the water pressure control unit 5, the piping length is less than 6 m at most. In addition, the air piping 14 is branched from the air header piping 13 arranged at the top of the water pressure control unit 5, and is connected to the three-way solenoid valve 15 in the water pressure control unit 5, so the piping length is 2 to 3.
It is m.

Therefore, since the air header piping 13 and the air piping 14 have short piping lengths, it is possible to sufficiently remove dust and the like mixed in the piping during piping construction, and then install the piping after removing the dust. On the other hand, since the air supply pipe 12 is very long, it is difficult to sufficiently remove dust and the like from inside the pipe, and there is also a risk that dust and the like may be mixed in from the air source.

If dust or the like is mixed in the air supply piping 12,
Due to air flow, air supply piping 12, air header piping 1
There is a risk that dust may enter the three-way solenoid valve 15 through the three-way solenoid valve 3 and the air pipe 14, causing the three-way solenoid valve 15 to malfunction. If a malfunction occurs, even if the power is turned off by the scram signal and the three-way solenoid valve 15 is demagnetized, dust etc. will leak from the valve seat and the time required for the scram inlet valve 6 and scram outlet valve 7 to fully open will be reduced. becomes longer.

As a result, a situation may occur in which the control rods 4 are not inserted into the fuel assembly within the reactor within the specified time.

In addition, if the seat portion of the valve becomes too large, the scram inlet valve 6
It is also conceivable that an emergency situation may occur in which the scram outlet valve 7 is not opened and the control rods 4 are not inserted into the fuel assembly in the reactor.

The present invention has been made in consideration of the above-mentioned circumstances, and prevents dust, etc., which would impair scram performance, from entering the three-way solenoid valve, ensures sound scram performance, and improves the overall plant performance. The purpose of the present invention is to provide a control rod-driven hydraulic device that can improve safety.

[Structure of the invention]

(Means for Solving the Problems) The control rod drive hydraulic system of the present invention includes a control rod drive mechanism for moving control rods in and out of the reactor, a scram inlet valve that supplies high-pressure drive water for emergency insertion of control rods, A water pressure tiIIwJ unit that is equipped with a scram outlet valve that drains the drive water and determines the drive water flow path, a three-way solenoid valve that supplies and discharges operating air pressure that opens and closes the scram inlet valve and the scram exit valve, and a three-way solenoid valve that In a control rod drive hydraulic system, the air supply system includes a filter for purifying the working air upstream of the three-way solenoid valve, and a filter for purifying the working air on the upstream side of the three-way solenoid valve. Equipped with a pressure sensing device to monitor clogging status,
The pressure sensing device is connected to an alarm device that generates an alarm when it senses a clogging condition.

(Function) In the control rod drive hydraulic system of the present invention, during normal operation of the nuclear reactor, the three-way solenoid valve is energized, and operating air pressure is led from the air source and supplied to the scram inlet valve and the scram outlet valve, Both the scram inlet valve and the scram exit valve are held fully open.

When a scram signal is issued during a reactor abnormality, the three-way solenoid valve is demagnetized, cutting off the working air pressure from the air source, and as the working air pressure is released to the atmosphere, the scram inlet valve and scram outlet valve instantly fully open. be done. Then, high-pressure driving water is supplied to the control rod drive mechanism, and the control rods are urgently inserted into the reactor, stopping the reactor.

The scram inlet valve and the scram outlet valve are opened and closed by supplying and cutting off working air pressure from an air source to the three-way solenoid valve. At this time, the operating air pressure to the three-way solenoid valve is supplied through the air supply system, but the filter installed upstream of the three-way solenoid valve in the air supply system prevents dust from entering the air supply system from entering the three-way solenoid valve. Prevent this from happening.

In addition, the presence or absence of filter clogging can be monitored by changes in the pressure of the operating air pressure, which is carried out by pressure monitoring devices, and the presence or absence of filter clogging can be monitored by the pressure monitoring device, and the presence or absence of filter clogging can be determined by the minimum required amount required to operate the scram inlet valve and scram outlet valve. When the pressure falls below the pressure, a pressure monitoring device detects this and an alarm device issues an alarm.

(Example) An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 20 shown in FIG. 1 is a control rod drive mechanism attached to a lower end plate 21 of the reactor pressure vessel.

The control rod drive mechanism 20 includes a hydraulically driven piston 2 that moves the control rods 22 in and out between a set of four fuel assemblies (not shown).
3, and by this piston 23, 1lltll
By driving the rod 22, the output υ of the reactor is controlled. On the other hand, the control rod drive mechanism 20 is connected to a hydraulic control unit 26 via an insertion pipe 24 and a withdrawal pipe 25. The control rod drive mechanism 20 and the hydraulic control unit 26 have a one-to-one correspondence, for example,
185 units of each are installed at 1,100 MWI@child couplet. The correspondence relationship between the hydraulic control unit 26 and the control rod drive mechanism 20 may be one to two or more.

The insertion pipe 24 is connected to the lower surface side of the hydraulic drive piston 23 of the control rod drive mechanism 20, and is designed to allow the control rod 22 to be inserted into the reactor urgently during a scram, using high-pressure drive water as the drive energy source. The water pressure control unit 2
It will be supplied from 6 onwards. Water pressure 1IIIIIIl
Unit 26 is an accumulator device N that stores high-pressure driving water.
27 and a scram inlet valve 28. Reference numeral 29 is a gate valve that isolates the water pressure control unit 26.

The accumulator device 27 includes an accumulator 30 that stores high-pressure water necessary to drive the hydraulic drive piston 23 housed in the control rod drive mechanism 20, and controls the high-pressure water stored in this accumulator 30 within a specified time. It has a nitrogen container 31 that stores nitrogen gas at the pressure and volume necessary to be supplied to the rod drive mechanism 20. In this accumulator device 27, the water piping 32 is filled with pressurized water pressurized by a control-driven water pump of a water pressure supply device (not shown).
is supplied to the accumulator 30. This supply compresses the nitrogen gas in the nitrogen container 31 and stores it as high-pressure drive water for driving the piston 23 of the control rod drive mechanism 20 .

In addition, the riverbed piping 25 is IIJ ml rod drive 11412
In order to discharge the return water from 0, the control rod part e mechanism 20
The piston 23 is connected from the upper surface side to a scram discharge facility 36 via a gate valve 33 in the water pressure control unit 26, a scram outlet valve 34, and a scram discharge pipe 35. This scram discharge facility 36 is isolated from the control rod vJ mechanism 20 and is at atmospheric pressure.

The scram inlet valve 28 and the scram outlet valve 34 are formed of air-operated diaphragm valves or the like, and these valves are opened by operating air pressure.

The operating air pressure is determined by the instrument air piping system (r
A system) is supplied via an air supply system 40 consisting of an air supply pipe 37, an air header pipe 38, and an air pipe 39,
The air is led to the scram inlet valve 28 and the scram outlet valve 34 by an air connection pipe 42 via a three-way solenoid valve 41 provided in the air pipe 39 .

On the upstream side of the air header piping 38 of the air supply system 40, a filter 43, switching valves 44a and 44b, and a pressure sensing device 45 are installed.
are provided respectively, and an alarm device 46 is connected to this pressure sensing device 45.

The filter 43 is connected to an air supply pipe 37 led from an air source.
The three-way solenoid valve 41 prevents dust and the like from entering the three-way solenoid valve 41 due to air flow, and a plurality of solenoid valves are connected in parallel as shown. The switching valves 44a and 44b are filters 43
The filters 43 are disposed before and after the filters 43, and are switched to use one of the filters 43 selectively.

The pressure sensing device 45 monitors the filter 43 for clogging;
An alarm device 46 sends an electrical signal when the operating air pressure required to open and close the scram inlet valve 28 and the scram outlet valve 34 decreases below the minimum required pressure due to clogging of the filter 43.
Output to. The alarm device 46 receives the electric signal output from the pressure sensing device 45 and generates an appropriate alarm such as sound or light.

In addition, the three-way solenoid valve 41 is turned 0N-O by the scram signal.
It is connected by wiring 50 to a power source (not shown) that is turned off. During normal reactor operation, the three-way solenoid valve 41 is turned on.
is energized and supplies actuating air pressure to scram inlet valve 28 and scram outlet valve 34 to fully open them. Conversely, when the reactor is abnormal, it is turned off, the three-way solenoid valve 41 is demagnetized, the operating air pressure is cut off, and the scram inlet valve 28 and scram exit valve 34 are opened to the atmosphere and fully opened.

Next, the operation of the control rod drive hydraulic system will be explained.

During normal operation of the reactor, the three-way solenoid valve 41 is energized, and the operating air pressure led from the air source is applied to the air supply pipe 37.
, is supplied via the air supply system 40 of the air header piping 38. At this time, the operating air pressure passes through the filter 43, switching valves 44a, 44b, and air piping 39 provided in the air header piping 38, and then passes through the three-way solenoid valve 41 and air connection piping 42 to the scram inlet valve 28 and scram is supplied to the outlet valve 34 which in turn supplies the scram inlet valve 28
and scram outlet valve 34 are both held in a full-blade condition.

Furthermore, when a scram signal is output during abnormal operation of the nuclear reactor, the power is turned off, the three-way solenoid valve 41 is demagnetized, and the operating air pressure from the air source is cut off.

Then, the scram inlet valve 28 and the scram outlet valve 34
The operating air pressure that had been supplied to the three-way solenoid valve 41 is rapidly released to the atmosphere via the air connection pipe 42, and the scram inlet valve 28 and the scram exit valve 34 are instantly fully opened. When the scram inlet valve 28 is fully opened, the high-pressure drive water stored in the accumulator device 27 flows through the scram inlet valve 28, the gate valve 29, and the insertion pipe 24 to the lower surface side of the hydraulic drive piston 23 of the control rod drive mechanism 20. is supplied, and the piston 23 rises. On the other hand, the scram outlet valve 34 is also fully opened, and as the piston 23 rises, the piston 23
The return water on the upper surface is discharged into the scram discharge equipment 36 via the usage pipe 25, the gate valve 33, the scram outlet valve 34, and the scram discharge pipe 35. As a result of the piston 23 being raised in this manner, the control rods 22 are inserted between the fuel assemblies of the reactor core at an indeterminate rate, and the operation of the nuclear reactor is stopped.

Furthermore, after the scram ends, a reset signal is output, the power is turned on, and the three-way solenoid valve 41 is energized again. The energized three-way solenoid valve 41 transfers operating air pressure to the scram inlet valve 28 and the scram outlet valve 3 via the air connection pipe 42.
4 and fully close the scram inlet valve 28 and scram outlet valve 34.

That is, scram inlet valve 28 and scram outlet valve 3
The three-way electromagnetic valve 41, which supplies and shuts off the working air pressure for opening and closing the valve 4, is supplied with working air pressure from an air source through an air supply system 40 including an air supply pipe 37, an air header pipe 38, and an air pipe 39. .

At this time, the filter 43 provided in the air header pipe 38 prevents dust in the air supply pipe 37 from entering the three-way solenoid valve 41.

Further, the presence or absence of clogging in the filter 43 is determined by a pressure monitoring device 45 that monitors changes in the working air pressure of the air flowing in the air header piping 38 due to clogging. An electrical signal is generated by the pressure monitoring device 45 when the filter 43 is clogged and the pressure drops below the minimum required pressure necessary to operate the scram inlet valve 28 and the scram outlet valve 34. The electrical signal generated by the pressure monitoring device 45 causes an alarm to be generated by the alarm device 46.

On the other hand, switching valves 44a and 4 disposed before and after the filter 43
4b is operated when switching to use a clogged filter 43.

〔Effect of the invention〕

As explained above, the control rod drive hydraulic system according to the present invention is capable of transmitting working air pressure from an air source that has passed through a filter for 1 m on three sides.
Since the air is supplied to the scram inlet valve and scram outlet valve via the valve, dust and the like in the piping will not be mixed into the three-way solenoid valve as the air flows.

Therefore, since the three-way solenoid valve is protected from dust and the like in the piping from the air source to the filter, malfunctions due to dust and the like do not occur. Therefore, the scram time of the control rod drive mechanism is not delayed, the scram can be reliably completed within the specified time, and there is no occurrence of an emergency in which the scram cannot be performed, and the soundness of the scram performance can be improved.
It can improve the reliability of plant operation and contribute to improving the safety of the entire plant.

Further, even if the filter becomes clogged and the operating air pressure decreases, the pressure sensing device and alarm device can detect the clogged state of the filter in advance. Therefore, the filter can be replaced using the switching valve before the operating air pressure drops below the minimum pressure required to open and close the scram inlet valve and scram outlet valve. This can be prevented and, as a result, the operating rate of the plant can be improved.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a condylar system configuration diagram showing an embodiment of the control rod drive hydraulic system according to the present invention, and Fig. 2 is a schematic system configuration diagram showing a conventional control rod drive hydraulic system. be. 1... Lower end plate, 2... Control rod drive mechanism, 3...
Piston, 4... Control rod, 5... Water pressure control unit, 6... Scram inlet valve, 7... Scram outlet valve,
8...Accumulator, 9...Insertion piping, 10...
・Pull-out piping, 11... Scram discharge equipment, 12...
Air supply piping, 13... Air header piping, 14...
Air piping, 15... Three-way solenoid valve, 16... Air connection piping, 20... Control rod drive mechanism, 21... Lower head plate, 22... Control rod, 23... Hydraulic drive piston, 2
4... Insertion pipe, 25... Retraction pipe, 26... Water pressure υ control unit () lctJ), 27... Accumulator device, 28... Scram inlet valve, 30... Accumulator, 31 ...Nitrogen container, 32.. Filling water piping, 34.. scram outlet valve, 35.. scram discharge piping, 36.. scram discharge equipment, 37.. air supply piping, 38.. Air header piping, 39... Air piping, 40... Air supply system, 41... Three-way solenoid valve, 42... Air connection piping, 43... Filter, 44
a. 44b...Switching valve, 45...Pressure sensing device, 46.
...Alarm device, 50...Wiring. Applicant's agent Hisaimo Hatano f times

Claims (1)

[Claims] 1. A control rod drive mechanism for moving control rods in and out of a nuclear reactor, a scram inlet valve for supplying high-pressure drive water for emergency insertion of control rods, and a scram outlet valve for draining drive water;
A water pressure control unit that determines the drive water flow path, a three-way solenoid valve that supplies and discharges operating air pressure to open and close the scram inlet valve and scram outlet valve, and the operating air pressure that is supplied to the scram inlet valve and scram outlet valve through this three-way solenoid valve. In a control rod-driven hydraulic system comprising an air supply system, the air supply system is provided with a filter for purifying working air upstream of a three-way solenoid valve, and a pressure sensing device for monitoring a clogging state of the filter. , wherein the pressure sensing device is connected to an alarm device that generates an alarm when detecting a clogging state. 2. The air supply system has an air supply pipe, an air header pipe branched from the air supply pipe, and an air pipe separated from the air header pipe. The control rod drive hydraulic system according to claim 1, further comprising a pressure monitoring device for monitoring. 3. The control rod drive hydraulic system according to claim 2, wherein a plurality of filters provided in the air header piping are connected in parallel, and switching valves are provided on the upstream and downstream sides of each filter.