JPS62285097A - Hydraulic control unit inspection 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 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an inspection device for a hydraulic control unit of a hydraulic system that drives control rods of a boiling water reactor, and in particular, The present invention relates to a water pressure control unit inspection device suitable for measuring and inspecting pilot solenoid valves.

[Conventional technology]

As shown in Figure 4, the reactor has a plurality of control rods (
(hereinafter referred to as CR) 2 are arranged, and one end of each CR 2 is connected to a piston 4 of a hydraulic piston type control rod drive mechanism (hereinafter referred to as CHD) 3 for insertion and withdrawal thereof. Each of these CRDs 3 is provided with a water pressure control unit (hereinafter referred to as HCU) 5 outside the containment vessel of the reactor 1 for controlling driving water supplied to each of these CRDs 3.

The HCU 5 is constantly supplied with various water pressures adjusted by the control rod drive hydraulic system, and in response to signals from the central control room, the HCU 5 supplies the necessary water pressure to the CRD 3 and
The output of the reactor 1 is controlled by inserting and withdrawing the reactor 2. The control rod drive hydraulic system is connected to a mask control, which will be described later, provided on the discharge side of a pump 6 that is connected to a water source (not shown) and supplies water for driving the control rods, through piping 7, and is connected to a water source (not shown) to switch the flow path of the drive water and to control the flow of water for the drive water. HCU5, which controls
It is composed of a CRD 3 that drives R2, pipes 8 and 9 that connect Hcus and CRD 3, and the like. In addition, in order to supply high pressure water to CRD3 in the event of an emergency shutdown of the reactor,
(The J5 is provided with an accumulator 10 and a nitrogen gas container 11, and the piping 8 connecting the accumulator 10 and the CRD 3 is provided with an inlet scram valve 12 and an isolation valve 13. Also, the scram discharge from the CRD 3 Piping 1 connecting said inlet scram valve 12 and scram discharge vessel 14 for rapid discharge of water into scram discharge vessel 14
5 is an outlet scram valve 16. Check valve 17. The HCIJ 5 is provided with scram pilot valves 19a and 19b for air control of the isolation valve 18 and the inlet/outlet scram valves 12 and 16 for air control. Also outlet scram valve 1
6 and the CRD 3 is provided with an isolation valve 20, and the pipe 7 is provided with an isolation valve 21. A check valve 22 and a master control 23 are provided.

This mask control 23 is connected to the header piping 24°25.
26 and a selection valve 27, which controls the pressure and flow rate of the driving water. Further, the scram pilot valve 19 and the scram discharge container 14 are connected by an air pipe 29 provided with a ball valve 28. 30 is a test plug provided in the scram pilot valve 19.

In the conventional HCU 5 configured as described above, high-pressure water in an emergency is transferred between the mask control 23 and the HCIJ 5 via the accumulator filling water piping 7, and the isolation valve 2
1 and the check valve 22 in the accumulator 10. During an emergency shutdown of the reactor 1, the scram pilot valve 19 is turned OFF by a signal from the emergency shutdown system, and the closing operation air pressure of the inlet/outlet scram valves 12 and 16 is rapidly released to open them, and the high-pressure water accumulated in the accumulator 10 is released. The piston 4 of the CRD 3 is operated through the piping 8, and the CR2 is inserted into the reactor core. At this time, water on the upper surface of the piston 4 is discharged into the scram discharge container 14 via the piping 9 and the output column valve 16.

As mentioned above, the control rod drive hydraulic system converts HC: 1lJ5 to C
By providing one to one RD3, the safety devices are separated and made independent so that each CRD3 can be scrammed individually in the event of an emergency shutdown of the reactor 1. The inlet scram valve 12 suppresses the outflow of high-pressure water from the accumulator 10, which is a scram system water source, and maintains the scram function for a certain period of time even if the high-pressure water supply source disappears due to stopping of the control rod-driven water pump 6 or the like. It has an effect. In addition, the outlet scram valve 16 has the function of preventing unnecessary outflow of waste water under normal conditions.
Input and output loss clam valves 12.16 are thus important valves.
The scram pilot valve 19 for opening and operating must be periodically inspected to prevent unnecessary scrams or operational delays due to external leakage, seat leakage, etc.

Next, the scram pilot valve 1911 according to the conventional method
Q: What are the various inspection methods and laws? I will explain.

Isolation valve 13. prior to inspection. ．． 20 is closed, the drain valve 31 provided in the accumulator 10 is opened, and the high pressure water in the accumulator 10 is discharged. First, perform a seat leak test. After closing the ball valve 28, the power to the pilot valves 19a and 19b is cut off, the stopper of the test plug 30 is removed, and temporary piping is connected. Next, a transparent vinyl hose for leakage measurement is attached to the exhaust port of the pilot valve 19a, and a container serving as a measuring cup containing water is prepared at the tip of the vinyl hose.

Pilot valves 19a, 19. Input power to b and apply pressure of approximately 5 kg/ffl from the temporary piping. The pilot valves 19a, 19b are alternately turned on and off, and the amount of seat leakage is measured based on the amount of air leaking from the exhaust port.

Next, conduct a motion measurement test. The operation measurement test was performed using ball valve 28.
At the same time, the pilot valve unit is removed and installed in a volume tank provided at a predetermined location within the plant. The inlet side of the ball valve 28 is connected to an air pipe in the plant by a hose.

The hose is equipped with a pressure gauge and a pressure reducing valve. Power is input to the pilot valves 19a and 19b, and the pressure at which the reduced pressure stops leaking is read by a pressure gauge to measure the minimum operating pressure. Next, prepare and connect an electromagnetic oscilloscope, dynamic strain meter, ammeter, and voltmeter to measure operating time. First, input the pilot valve signal and the volume tank internal pressure signal to the electromagnetic oscilloscope, and use the pressure reducing valve to control the pilot valve 19a.
.

A predetermined pressure is applied to 19b. Turn the electromagnetic oscilloscope to 0N-OFFL with the switch, measure the time from the pilot valve demagnetization until the pressure in the volume tank starts to decrease using the oscilloscope chart paper, measure the operating time, and check the health of the pilot valves 19a and 19b. confirm.

Finally, the pilot valve unit is assembled to HCO5 and an airtight leakage test is performed. That is, pilot valves 19a, 19b
Input power to the pilot valves 19a and 19b and apply a predetermined pressure to each part to confirm that there is no external leakage.

The above is the conventional method of testing and inspecting the scram pilot valve 19. As disclosed in Japanese Unexamined Patent Publication No. 58-156295, a device that performs this type of test and inspection is a monitor that tests whether a pilot valve operates using an electric signal and outputs a warning signal when an abnormal operation is detected. Proposals for installing equipment,
As disclosed in Japanese Patent Application Laid-Open No. 60-206507,
Proposals are known in which the valve is operated while attached to the HCIJ, and its vibration is detected to confirm the operation of the valve. However, these proposals were only aimed at confirming the soundness of valve operation, and did not take into consideration airtightness, seat leak, operating time, and operating pressure measurement inspection points.

[Problem that the invention seeks to solve]

As mentioned above, the tests and inspections of scram pilot valves are diverse, and many types of inspection jigs and tools are required. i.e. volume tank.

It was troublesome to have to separately prepare an electromagnetic oscilloscope, dynamic strain measuring device, etc. In addition, the scram pilot valve 19 is installed above the HCO2 and is located at a height of 2 m or more, making inspection work difficult, requiring a large number of inspectors and inspection man-hours, and lengthening the periodic inspection period. There was also the problem of high radiation doses (8). Also, the scram pilot valve 19
Although inspection for external leakage and seat leakage can be performed even when assembled to HCIJ5, operation time measurement is not possible with HC'I
If the inspection is performed with the valve still assembled in 5, the diaphragm will move suddenly due to the sudden change in pressure, which will adversely affect the scram valve. For this reason, it was necessary to remove the pilot valve 19 from the HCO 5 and inspect it, resulting in an inspection at two locations. Another problem was that it required routing piping from the pressure source and assembling and connecting inspection tools.

The present invention has been made in view of the above-mentioned points, and is a water pressure control system for nuclear reactors that allows the soundness of the scram pilot valve to be easily confirmed, shortens the inspection period, and completely ensures accident preventive maintenance. An object of the present invention is to provide a control unit inspection device.

[Means for solving problems]

In order to achieve the above object, the present invention provides a volume tank in a gas pipe for airtight leakage inspection of a valve provided in a water pressure control unit, and also includes a detection device for detecting the operating time and operating pressure of the valve. A panel containing an electric circuit for operating the detection device is integrated with the piping and the volume tank.

[Effect]

According to the above configuration, since the piping system includes the volume tank associated with the scram valve, a predetermined pressure can be easily obtained using the pressure gauge and the pressure reducing valve. Moreover, since a detection device for detecting the operating time and operating pressure of the valve and a panel containing an electric circuit are integrally provided in the piping system,
By removing the scram pilot valve to be inspected from the HCLI and attaching it to this inspection device, all inspections can be performed efficiently and sequentially, significantly reducing the number of inspection steps.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the water pressure control unit inspection device according to the present invention will be described with reference to the drawings.

An embodiment of the present invention is shown in FIGS. 1, 2, and 3.

In this figure, parts that are the same as or equivalent to those shown in FIG. 4 are designated by the same reference numerals. The inspection device main body 32 has a first
As shown in the figure, a volume tank 33 is provided, and a pressure transducer 34, a dynamic strain measuring device 35, and an electromagnetic oscillograph 36 are connected in sequence to detect the pressure inside the volume tank 33. . The volume tank 33 is equipped with a valve 3 to release the internal pressure at the end of the test, etc.
7 is provided, and the pressure transducer 34 is provided with a hose 3.
8 and piping 39 are connected.

This piping 39 includes a valve 40 and a low pressure reducing valve 41 for fine adjustment.
is provided, and a coupler 42 is attached to the terminal. Also, two pressure gauges 43 and 44 are attached to this pipe 39, and one pressure gauge 44 has valves 45 and 46.
is provided. In addition, as a pressure source, a pressure of approximately 15
A 0kg/a1 nitrogen gas cylinder 47 is provided,
One end of a pipe 51 to which a pressure gauge 48, 49 and a high pressure reducing valve 50 are attached is connected. The other end of this piping 51 can be connected to a coupler 42 provided on the inspection device main body 32 via a hose 52.

On the other hand, the panel has a built-in electric circuit as shown in FIG. 2, one of the circuits input from the power source 53 is connected to the recording power connector 54.55, and the other is connected to the switch 56. Terminal block 57. Terminal block 5 via switch 58
9 is connected.

From this terminal block 59, a pilot valve power connector 60 is connected.
a and 60b, and the power connectors 54 and 55 are connected to an electromagnetic oscilloscope 36 and a dynamic strain measuring device 35, respectively. A pilot lamp 61 is provided between the switch 56 and the terminal block 57 to confirm whether the power is on or off, and a pilot lamp 61 is provided between the switch 58 and the terminal block 59 to confirm that the pilot valve 19 is energized. 62
a.

62b are provided, each attached to the panel 63. Note that 64 is a handle provided on the inspection device main body 32, and the inspection device main body 32 is placed on a storage box 66 having casters 65 so that it can be transported.

A method of inspecting the pilot valve unit 67 according to this embodiment configured as described above will be described below. First, the nitrogen gas cylinder 47 is connected to the inspection device main body 32 via the hose 52 and coupler 42. High pressure reducing valve 5 for nitrogen gas
0, the pressure is reduced to approximately 10 kg/d. Remove the pilot valve unit 67 from the HCυ5 and remove the volume tank 3.
3, the ball valve 28 of the pilot valve unit 67 and the inspection device main body 32 are connected with a hose 38. Power cord connector 60a, SOB to scram pilot valve 19
a and 19b, respectively, and connect the outlet to the power source 53 to input power.

Next, measure the minimum operating pressure. Since the pressure starts from zero, the low pressure reducing valve 41 is adjusted to zero. Valve 45.
46 is opened to make the pressure inside the pipe 39 zero, and this is confirmed with the pressure gauge 44.

Then valves 46,37 are closed and valve 40 is opened. Switch 56.
58 to close the scram pilot valve 19a.

Turn on 19b. Then, adjust the low pressure reducing valve 41,
The pressure is gradually increased while monitoring the pressure gauge 44, and the pressure at which gas emission stops from the exhaust port of the scram pilot valve 19a is read by the pressure gauge 44, thereby measuring the minimum operating pressure.

Next, an airtightness test is performed following the minimum working pressure measurement described above.

The valves 45 and 46 are closed, and the low pressure reducing valve 41 is adjusted to a predetermined pressure while monitoring the pressure gauge 43. Next, turn on the switches 56 and 58 to pressurize each pilot valve 19a, 19b and volume tank 33, and confirm that there is no external leakage in each part.

Next, a seat leak test is conducted following the above airtight test. A leak measuring device 68 is connected to the exhaust port of the scram pilot valve 19a via a leak measuring hose. Then, the switches 56 and 58 are set to ON-OFF to control the pilot valve 19a under each condition.

Measure the amount of seat leakage of No. 19b.

Next, the operation time is measured following the seat leak test described above. A power connector 55 is connected to the dynamic strain measuring device 35, and a power connector 54 is connected to the electromagnetic oscillograph 36, respectively. Next, the pilot valves 19a and 19 are activated by switches 56 and 58.
b&ON, pressurize the volume tank 33 to a predetermined pressure, turn on the chart drive switch (not shown) of the electromagnetic oil graph 36, and turn off the switch 56.
shall be. When the measurement is finished, turn off the chart drive switch.
Take out the chart paper as F and determine the time from demagnetization of the pilot valve until the pressure in the volume tank begins to decrease.

The soundness of the scram pilot valve 19 can be confirmed by comparing the above values with preset allowable values.

According to this embodiment, the number of inspection steps for the HCU scram pilot valve 19 can be reduced by about 60%. For example, in the case of a 110 MWe nuclear power generation facility, there are 185 units of HC'J5,
An inspection that would take approximately 739 hours using the conventional method can be completed in approximately 296 hours using the inspection apparatus of this embodiment. Additionally, the radiation dose during inspection work can be reduced by approximately 40% compared to conventional methods. Furthermore, the reliability of deterioration diagnosis is improved and the operating rate of nuclear power plants can be improved. At the same time, due to the reduction in inspection man-hours, personnel costs can be reduced by about 60% compared to conventional methods, and the length of time that skilled inspectors are detained can be reduced by about 0%, making it a great contribution to other inspections. Moreover, since the inspection device is small and compact, it can be easily moved within narrow passages.

〔Effect of the invention〕

As described above, according to the present invention, the inspection device for the scram pilot valve provided in the hydraulic control unit that controls the control rods of the nuclear reactor is constructed by integrally incorporating the piping system and the electric circuit, and The small and compact inspection device enables a series of measurements in a short time, making it easy to check the health of the valves in the HCυ, improving the reliability of scram function maintenance6.

[Brief explanation of drawings]

Fig. 1 is a schematic system diagram showing one embodiment of the water pressure control unit inspection device according to the present invention, Fig. 2 is an electric circuit diagram of this embodiment, and Figs. 3 (a) and (b) are A front view and a side view showing the external appearance, respectively, and FIG. 4 are a system diagram showing a reactor control rod drive hydraulic system to which the inspection device according to this embodiment is applied. 1... Nuclear reactor, 2... Control rod (CR), 8...
Control rod drive mechanism (CHD), 5...Hydraulic pressure control unit (HC'U), 19...Scram pilot valve, 32
... Inspection device main body, 33 ... Volume tank, 3
9...Piping, 63...Panel.

Claims (1)

[Claims] 1. In a water pressure control unit inspection device for a control rod drive hydraulic system of a nuclear reactor, a volume tank is provided in the gas piping for airtight leakage testing of the valve provided in the water pressure control unit, and the operating time and operating pressure of the valve are measured. A water pressure control unit inspection device characterized in that a detection device for detection and a panel containing an electric circuit for operating the detection device are integrated with the piping and the volume tank.