JPH0455280B2 - - Google Patents

Description

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

[Conventional technology]

As shown in Figure 4, a plurality of control rods (hereinafter referred to as CR) 2 are installed at the bottom of the reactor 1 for normal output control and scram stop, and each CR2 is In order to insert and withdraw these, a control rod drive mechanism (hereinafter referred to as
(referred to as CRD) 3 is connected to a piston 4. Each of these CRDs 3 is provided with a hydraulic control unit (hereinafter referred to as HCU) 5 outside the containment vessel of the nuclear reactor 1 for controlling the drive 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 the HCU 5 adjusts the necessary water pressure in response to signals from the central control room.
The output of the reactor 1 is controlled by supplying it to the CRD3 and inserting and withdrawing the CR2. The control rod drive hydraulic system is connected by piping 7 to a master control, which will be described later, and which is installed on the discharge side of a pump 6 that is connected to a water source (not shown) and supplies control rod drive water. HCU5 controls
, CRD3 that drives CR2, HCU5 and CRD
It is composed of pipes 8, 9, etc. that connect 3. In addition, in order to supply high pressure water to CRD 3 during an emergency shutdown of the reactor, HCU 5 has an accumulator 1.
0 and a nitrogen gas container 11 are provided, 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. In addition, a pipe 15 connecting the inlet scram valve 12 and the scram discharge container 14 for rapidly discharging scram discharge water from the CRD 3 into the scram discharge container 14 includes an outlet scram valve 16 and a check valve 1.
7. Isolation valve 18 and inlet/outlet scram valves 12, 16
The HCU 5 is provided with scram pilot valves 19a, 19b for pneumatic control of opening/closing operations. Further, the piping 9 connecting the outlet scram valve 16 and the CRD 3 is provided with an isolation valve 20, and the piping 7 is provided with an isolation valve 21, a check valve 22, and a master control 23. This master control 23 is connected to the header piping 24, 2.
5, 26 and a selection valve 27,
It controls the pressure and flow rate of 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 connected to the master control 23.
The water is transferred between the HCU 5 and the accumulator filling water pipe 7, and stored in the accumulator 10 via the isolation valve 21 and check valve 22. reactor 1
During an emergency stop, the scram pilot valve 19 is turned OFF by a signal from the emergency stop system, and the closing air pressure of the inlet and outlet scram valves 12 and 16 is rapidly released to open them, and the high-pressure water accumulated in the accumulator 10 is drained through the pipe 8. Through CRD3 piston 4
Activate the CR2 and insert it into the reactor core. At this time, the water on the top surface of the piston 4 is removed from the piping 9 and the outlet clam valve 16.
is discharged to the scram discharge container 14 via the scram discharge container 14.

As mentioned above, the control rod drive hydraulic system uses HCU5.
By providing one to one CRD3, 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 accumulation generator 10, which is the 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 the stoppage of the control rod-driven water pump 6 or the like. It has an effect. The outlet scram valve 16 also has the function of preventing unnecessary outflow of waste water under normal conditions. The scram pilot valve 19 for opening and closing the inlet/outlet scram valves 12 and 16, which is an important valve as described above, needs to be inspected periodically to prevent unnecessary scrams or operational delays due to external leakage, seat leakage, etc. .

Next, the scram pilot valve 1 using the conventional method
9 various inspection methods will be explained.

After closing the isolation valves 13 and 20 prior to the inspection,
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. ball valve 28
After closing the pilot valves 19a and 19b, the power to the pilot valves 19a and 19b is cut off, the stopper of the test plaza 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.

Input power to the pilot valves 19a and 19b,
Approximately 5 kg/cm ² of pressure is applied from the temporary piping. Turn power on and off alternately to pilot valves 19a and 19b
and measure the amount of seat leakage based on the amount of air leaking from the exhaust port.

Next, conduct a motion measurement test. The operation measurement test is performed by removing the pilot valve unit together with the ball valve 28 and attaching it to 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, the pressure is gradually increased by the pressure reducing valve, and the pilot valve 1 is
The minimum operating pressure is measured by reading the pressure when the diaphragms in 9a and 19b switch and the leakage from the exhaust port stops using a pressure gauge. Next, prepare and connect an electromagnetic oscillograph, dynamic strain meter, ammeter, and voltmeter to measure operating time. First, a pilot valve signal and a volume tank internal pressure signal are input to the electromagnetic regulator, and a predetermined pressure is applied to the pilot valves 19a and 19b using the pressure reducing valve. Turn the electromagnetic switch ON and OFF with a switch, measure the time from when the pilot valve is demagnetized until the pressure in the volume tank starts to decrease using a switch chart, measure the operating time, and then turn the pilot valve 19a,
Check the health of 19b.

Finally, assemble the pilot valve unit to HCU5 and perform an airtight leak test. That is, the power is input to the pilot valves 19a and 19b, and the pilot valve 1
A predetermined pressure is applied to 9a and 19b to confirm that there is no external leakage from each part.

The above is the conventional method for testing and inspecting the scram pilot valve 19. As disclosed in Japanese Unexamined Patent Publication No. 58-156295, an example of a device for performing this type of test and inspection is a monitoring system that tests whether a pilot valve operates using an electric signal and outputs a warning signal when an abnormal operation is detected. There are proposals to install a device, as disclosed in Japanese Patent Application Laid-Open No. 60-206507, to operate the valve while it is attached to the HCU, and to detect the vibration to confirm the operation of the valve. There is. However, these proposals were only aimed at confirming the soundness of valve operation, and did not take into account airtightness, seat leak, operating time, and operating pressure measurement inspection.

[Problem that the invention seeks to solve]

As mentioned above, the tests and inspections of scram pilot valves are diverse and require a wide variety of testing jigs and tools. i.e. volume tank,
It was troublesome to have to separately prepare an electromagnetic oscillograph, a dynamic strain measuring device, etc. In addition, the scram pilot valve 19 is installed at the top of the HCU 5 and is located at a height of 2 m or more, which makes inspection work difficult, requiring a large number of inspectors and inspection man-hours, and lengthening the regular inspection period. There was also the problem of high exposure doses. In addition, inspection for external leakage and seat leakage of the scram pilot valve 19 is performed using the HCU.
Although inspection can be performed even when the unit is attached to HCU 5, the operation time measurement is performed when the unit is attached to HCU 5.
The sudden change in pressure causes the diaphragm to move suddenly, which adversely affects the scram valve. For this reason, it was necessary to remove the pilot valve 19 from the HCU 5 and inspect it, which required 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 a nuclear reactor that allows the soundness of the scram pilot valve to be easily confirmed, shortens the inspection period, and completely ensures accident preventive maintenance. The 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 hydraulic control unit inspection device for a control rod drive hydraulic system of a nuclear reactor, in which a connection part to one end of a scram pilot valve to be inspected which has been removed from a hydraulic control unit is provided. a volume tank which simulates the operating air volume of another scram valve operated by the valve in a connected state; A pressure transducer that converts the amount of air into air and has a connection to the other end of the scram pilot valve, a dynamic strain measuring device connected to this pressure transducer, and an electromagnetic strain measuring device connected to this dynamic strain measuring device. an oscilloscope, a pressure adjustment pipe having a connection part to a pressure source at the tip, a pressure adjustment pipe having a proximal end connected to the pressure device, a valve and a pressure gauge, and the scram pilot valve connected to a power source during inspection. , an electric circuit for operating a dynamic strain measuring instrument and an electromagnetic oscilloscope.

[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. Furthermore, since a panel containing a detection device and an electric circuit for detecting the operating time and operating pressure of the valve is integrated into the piping system, the scram pilot valve to be inspected can be removed from the HCU and attached to this inspection device. For example, all inspections can be performed efficiently and sequentially, and the number of inspection steps can be significantly reduced.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a water pressure control unit inspection apparatus according to the present invention will be described below 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. As shown in FIG. 1, the inspection device main body 32 is provided with a volume tank 33, and is equipped with a pressure transducer 34, a dynamic strain measuring device 35, and an electromagnetic oscillograph 3 for detecting the pressure inside the volume tank 33.
6 are connected in sequence. The volume tank 33 is provided with a valve 37 to release the internal pressure at the end of the test, and a pressure transducer 34 is provided.
A hose 38 and piping 39 are connected to. This piping 39 is provided with a valve 40 and a low pressure reducing valve 41 for fine adjustment, and a coupler 42 is attached to the end. Further, two pressure gauges 43 and 44 are attached to this pipe 39, and one pressure gauge 44 is provided with valves 45 and 46. Additionally, a nitrogen gas cylinder 47 with a pressure of approximately 150 kg/cm ² is separately provided as a pressure source, and pressure gauges 48, 49
and one end of a pipe 51 to which a high pressure reducing valve 50 is attached is connected. The other end of this pipe 51 is connected to a coupler 42 provided in the inspection device main body 32.
It can be connected to 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 inputted from the power supply 53 is connected to the recording power connectors 54 and 55, and the other is connected to the switch 56 and the terminal block. 57, and is connected to a terminal block 59 via a switch 58. This terminal block 59 is connected to pilot valve power connectors 60a and 60b, and the power connectors 54 and 55 are connected to the electromagnetic oscillograph 3, respectively.
6 and a dynamic strain measuring device 35. There is a power ON/OFF connection between the switch 56 and the terminal block 57.
A pilot lamp 61 for checking is provided between the switch 58 and the terminal block 59 to check that the pilot valve 19 is energized.
2a and 62b are provided, and each is attached to the panel 63. Note that 64 is a handle provided on the inspection device main body 32;
2 is placed on a storage box 66 having casters 65 so that it can be transported. As explained above, the present invention has a connecting part to one end (19b side) of the scram pilot valve 19 to be inspected which is removed from the water pressure control unit 5, and the valve 19 is connected to the valve 19 in the connected state. A volume tank 33 that simulates the operating air amount of other operated scram valves 12 and 16, and a volume tank 33 that is connected to this volume tank 33 and measures changes in pressure within the volume tank 33 and converts the pressure into an air amount. and a pressure transducer 34 having a connection portion to the other removed end (ball valve 28 side) of the scram pilot valve 19.
, a dynamic strain measuring device 35 connected to this pressure transducer 34, an electromagnetic oscilloscope 36 connected to this dynamic strain measuring device 35, and a pressure source ( _N2 cylinder 4
7), the proximal end is connected to the pressure transducer 34, and the valves 40, 41, 4
5, 46 and pressure gauges 43, 44; an electric circuit connected to a power source 53 and operating the scram pilot valve 19, dynamic strain measuring device 35, and electromagnetic oscilloscope 36 during inspection; It is equipped with the following.

A method of inspecting the pilot valve unit 67 according to this embodiment configured as described above will be explained below. First, the nitrogen gas cylinder 47 is connected to the inspection device main body 32 via the hose 52 and coupler 42. Nitrogen gas is approximately 10Kg/cm ² by high pressure reducing valve 50.
The pressure is reduced to Pilot valve unit 67
Remove it from the HCU 5, attach it to the volume tank 33, and connect the ball valve 28 of the pilot valve unit 67 and the inspection device main body 32 with a hose 38. The power cord connectors 60a and 60b are connected to the scram pilot valves 19a and 19b, respectively, and the outlet is connected 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. The valves 45 and 46 are opened to make the pressure in the pipe 39 zero, and this is confirmed with the pressure gauge 44.
Next, valves 46 and 37 are closed and valve 40 is opened. Close the switches 56 and 58 and close the scram pilot valve 19.
Turn on a and 19b. and low pressure reducing valve 41
The pressure is gradually increased while monitoring the pressure gauge 44, and the pressure at which gas stops being discharged from the exhaust port of the scram pilot valve 19a is read by the pressure gauge 44 to measure 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 and 19b and the volume tank 33, and confirm that there is no external leakage from 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 turn switches 56 and 58 ON-OFF
Pilot valves 19a, 19b under each condition
Measure the amount of seat leakage.

Next, the operation time is measured following the seat leak test described above. A power connector 55 and a power connector 54 are connected to the dynamic strain measuring instrument 35 and the electromagnetic oscillograph 36, respectively. Next, the pilot valves 19a and 19b are turned on using the switches 56 and 58, and the volume tank 33 is pressurized to a predetermined pressure. Next, a chart drive switch (not shown) of the electromagnetic oscillograph 36 is turned ON, and the switch 56 is turned OFF. Once the measurement is complete, turn on the chart drive switch.
Set it to OFF, take out the chart paper, and calculate the time from when the pilot valve is demagnetized until the pressure in the volume tank starts to decrease.

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

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 HCU5 units, and the inspection that would take about 739 hours using the conventional method can be completed in about 296 hours using the inspection equipment of this embodiment. Additionally, the radiation exposure 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 approximately 60% compared to conventional methods, and the length of time that skilled inspectors are detained can be reduced by approximately 60%, making it a significant contribution to other inspections. Moreover, since the inspection device is small and compact, it can be easily moved within narrow passages.

[Effects 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 a nuclear reactor can be used to inspect the operation of other scram valves operated by the scram pilot valve. A volume tank that simulates the amount of air, a pressure transducer, a dynamic strain measuring device, and an electromagnetic oscillograph connected to this volume tank, pressure adjustment piping equipped with a valve and a pressure gauge, and the scram pilot valve at the time of inspection, Since the dynamic strain measuring instrument and the electric circuit that operates the electromagnetic oscillograph are integrated, a series of measurements can be performed in a short time with a small and compact inspection device, making it easy to check the health of the valves in the HCU. This improves the reliability of Scrum function maintenance.

[Brief explanation of the drawing]

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. 3a and 3b show the external appearance of this embodiment. A front view, a side view, and FIG. 4 are system diagrams 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), 3... Control rod drive mechanism (CRD), 5... Hydraulic control unit (HCU), 19... Scram pilot valve, 32
...Inspection device main body, 33...Volume tank,
39...Piping, 63...Panel.

Claims (1)

[Scope of Claims] 1. A water pressure control unit inspection device for a control rod drive hydraulic system of a nuclear reactor, which has a connection part to one end of a removed scram pilot valve to be inspected which has been removed from a water pressure control unit. a volume tank that simulates the operating air volume of other scram valves operated by the valve in the state; and a pressure transducer having a connection to the other removable end of the scram pilot valve;
a dynamic strain measuring device connected to this pressure transducer; an electromagnetic oscillograph connected to this dynamic strain measuring device; A water pressure control characterized by comprising: pressure adjustment piping equipped with a valve and a pressure gauge; and an electric circuit that is connected to a power source and operates the scram pilot valve, dynamic strain meter, and electromagnetic oscilloscope during inspection. Unit inspection equipment.