JPS60131491A - Hydraulic control unit - 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] The present invention provides water body control for driving control rods in nuclear power generation.
Regarding knitting.

Generally, in nuclear power generation, multiple fuel rods in a nuclear reactor emit neutrons to each other and split in a chain reaction to generate R heat and use this heat for power generation. The degree of fission is controlled by moving the control rod in and out. For example, by inserting a control rod between the fuel rods, the neutrons are absorbed and heat generation is suppressed, and by withdrawing the control rod from between the fuel rods, heat generation is accelerated.

The insertion and withdrawal displacement of this control rod is controlled by the side control shown in Figure 1! l
[This is done by your system.]

In FIG. 1, a control rod (not shown) is fixed to the upper end of a piston 2 fitted into a cylinder 1, and a selector valve 13 (4) for normal control of the control rod is connected to a pipe 3 connected to the upper and lower chambers of the cylinder 1. ~7) and emergency control scram valves 8 and 9 are arranged, and the scram valve 8 is equipped with an accumulator 1o (high-pressure water and high-pressure N2 are supplied to the cylinder 10a and the N2 container 1Ob, respectively).
) are connected.

When inserting the Win control rod, only the selector valve 5.7 is first opened, and water pressure is supplied to the lower chamber of the cylinder 1 through the selector valve 7 from the piping 3a, and the water pressure in the upper chamber of the cylinder 1 is supplied to the selector valve 5. The piston 2 (control rod) moves upward to perform the above-mentioned insertion. When the control rod is withdrawn, only the selector valve 4.6 is opened, and water pressure is supplied to the upper chamber of the cylinder 1 from the piping 3a via the selector valve 6, and the water pressure in the lower chamber of the cylinder 1 is supplied to the selector valve 4. It is led out from the pipe 3b through the pipe 3b, and the above-mentioned drawing is performed. In addition, when stopping power generation in an emergency, the scram valve 8.9 is opened, and the high pressure water in the cylinder 10a of the accumulator 1O flows into the N2 container 10 via the piston 10c.
The high pressure N2 of b is rapidly supplied to the lower chamber of the cylinder 1 via the scram valve 8, and the water pressure in the upper chamber of the cylinder 1 is discharged via the scram valve 9, and the control rod is urgently inserted and Perform an emergency stop.

The angle valve 11 is provided in the middle of the pipe 12 so that the water in the accumulator 1O can be discharged to the outside.

In the water pressure control unit of the control rod drive control system described above, an instrumentation unit section (not shown) including a pressure gauge for measuring the pressure in the N2 container 1ob is provided in the middle of the pipe connected from the N2 container 10b to the cylinder 10a. The angle valve 1 is
After opening the valve 1 and moving the piston 10c upward due to the high pressure N2 of the accumulator 1o and discharging the water in the cylinder 10a and piping 12, the valve device (not shown) disposed before and after the pressure gauge is opened. Close the valve and perform maintenance and inspection work. However, conventionally, when water is discharged from the angle valve 11, the valve body of the angle valve 11 is displaced together with the valve shaft, and when the valve is opened, it remains separated from the valve seat, so the piston 10c
moves up to complete discharging the water in the cylinder 10a, and when the water in the piping 12 is further discharged, air flows into the piping 12 from the discharge port 11a of the angle valve 11 through the gap between the valve body and the valve seat. mixed into the inside. When the pipe 12 and the accumulator 1O are filled with water again while this air remains in the pipe 12, the scram valve 8 is opened during scram, which requires rapid reduction of the reactor heat, and the high pressure The water in the accumulator 1O is forcefully ejected into the cylinder 1 of the control rod drive device under the pressure of N2, and when the control rod is inserted into the fuel rod space due to the sudden lowering of the piston 2, the air flows into the piping 12.
The force of the water is reduced by the amount that is compressed inside, and the insertion speed of the control rod is delayed. Therefore, in order to prevent air from getting into the piping 12 when discharging the water in the water pressure control unit, when the water pressure in the piping 12 drops to a limit value that allows air to get mixed in, the angle valve 11 is conventionally closed. The valve must be closed, and the closing operation of the angle valve 11 also requires nerves.

Note that FIGS. 2 and 3 are a side view and a front view of the water pressure control unit corresponding to FIG. 1. In FIGS. 2 and 3, if the angle valve 11 is installed at a higher position than the scram valve 8, the above drawback can be easily solved, but the water pressure control unit is installed above the angle valve 11 with the selector valves 13 (4 to 4). 7
), scram valves 8 and 9, and many pipes that connect them are crowded together, so there is no installation space and angle valve 1
1 near the scram valve 8 was difficult.

The present invention displaces the valve body of the angle valve in the valve closing direction according to the pressure of driving water, without depending on the closing operation of the angle valve,
It is an object of the present invention to provide a water pressure control unit that eliminates the above-mentioned drawbacks by preventing air from entering the drive water outflow pipe through the function of the angle valve itself without any external operation.

The configuration for this purpose includes a scram valve that is opened during scram, an accumulator that supplies driving water to the control rod drive device through the opened scram valve, and an outflow of driving water between the scram valve and the accumulator. It consists of a discharge valve that is provided in communication with the piping and discharges the driving water to the outside, and the drain valve is arranged in the axial direction of the valve shaft in a separate and coaxial state with the valve shaft. It is composed of a valve body that is relatively displaceable within a predetermined dimension, and an energizing means that suppresses and biases the valve body in the valve closing direction, and when the valve opening is below a predetermined valve opening degree, the valve body moves within the above predetermined dimension range. It is configured to be displaced to a position in accordance with the pressure of the driving water and the urging force of the urging means.

Next, one embodiment will be explained. FIG. 4 is a diagram showing a water pressure control unit according to the present invention, and FIG. 5 is a longitudinal sectional view of an angle valve, which is a main part of the present invention.

Note that parts common to those in FIG. 1 are given the same reference numerals and their explanations will be omitted.

In FIG. 4, the angle valve (discharge valve) 21 has an inlet 23 connected to a branch pipe 22 of the driving water outflow pipe 12 that communicates the scram valve 8 and the accumulator 10, and is installed with the discharge "I24" facing downward. ing.

In FIG. 5, the valve shaft 25 of the angle valve 21 has an engaging portion 2 at the tip.
The valve body 26 is attached to the valve body 5a so as to be freely displaceable in the axial direction. chamber 26
It has b. The chamber portion 26b has an inner diameter larger than the outer diameter of the engaging portion 25a, and a depth larger than the axial thickness of the engaging portion 25a. They are engaged so that they can be relatively displaced by the size difference between the levers.

Further, the valve body 26 is located at the left end of the middle chamber part 26b in FIG.
Flange 26 forming a hole 26c smaller than the outer diameter of 5a
It has d.

28 is a coil spring (biasing member), which connects the flange 26d and the valve body 2.
It is provided between the spring receiving part 25b having an annular groove facing the collar part 26d of No. 6.

Therefore, the valve body 26 is biased by the elastic force of the spring 28 in the direction of arrow x1, which is the closing direction of the angle valve 21.

In addition, 29 is a valve body, and 30 is a valve body guide member.

31 is the seal holder, 32.33 is the O-ring.

34 is a backup ring, and 35 is a handle.

Next, FIGS. 6(A) and 6(B) show the action of the angle valve during maintenance and inspection of the instrumentation unit section of the water pressure control unit configured as described above and during gasket replacement.

This will be explained with reference to ('C) and (D) together.

As shown in FIG. 6A, normally, in the angle valve 21, the spherical tip of the engaging portion 25a of the valve shaft 25 comes into contact with the inner wall 26b-+ of the chamber 26b of the valve body 26. The tapered surface 26a of the valve is pressed against the valve seat 27, and the valve is closed.

When performing maintenance inspection and gasket replacement, the handle 35 is rotated to open the angle valve 21 to a predetermined valve opening as shown in FIG. 6(B), and the piping 12.2 shown in FIG. 4 is opened.
2 and the water filled in the accumulator 10 are high pressure N2
Since the valve body 26 is pressurized by the pressure of the spring 28
The taper surface 26a is displaced from the valve seat 27 by being suppressed by the large water pressure caused by the pressing force of . Therefore, the water in the pipes 12, 22 and the accumulator 1O is discharged from the discharge port 24 through the gap between the valve body 26 and the valve seat 27 as the piston 10c moves upward.

When the angle valve 21 is opened below the predetermined valve opening degree, the valve stem 2
The engaging portion 25a of the valve body 26 (1) of the valve body 26 in the closed position
and the inner wall 26b-: The valve element 26 is displaced in the valve opening or closing direction depending on the magnitude of the water pressure and the pressing force of the spring 28. That is, when the water pressure is greater than the elastic force of the spring 28, the valve body 26 is displaced in the direction of arrow x2 to a position where it abuts the engaging portion 25a, and the valve is opened, and the water in the accumulator 1O is drained. When this water is substantially discharged and the water pressure decreases to become smaller than the elastic force of the spring 28, the valve body 26 is displaced in the direction of arrow x1 by the pressing force of the spring 28 and closes. Note that when the valve body 26 is closed, the engaging portion 25a does not come into contact with the flange portion 26d of the valve body 26, but is spaced apart, and does not prevent the valve body 26 from closing.

That is, as shown in FIG. 6(C), the piston 10c of the accumulator 1O discharges the water in the cylinder 10a and -1-
When the valve movement is completed, the water in the pipe 12.22 is no longer pressurized and the water pressure is reduced. Then, at the same time that the water pressure reaches the limit value that allows air to enter from the outside, the valve body 2
6 immediately closes the angle valve 21 by the pressing force of the spring 28. Therefore, when the driving water is discharged by the angle valve 21, there is no room for air to get mixed in through the angle valve 21, and air mixing is prevented, and unlike the conventional case, there is no need to worry about operating the handle when closing the valve. Furthermore, as will be described later, when the accumulator 1O is filled with water again, air will not be mixed in, thereby improving the reliability of the operation during scram.

After draining the water from the accumulator 1O, the valve devices installed before and after the pressure gauge are closed, and the instrumentation unit section is disassembled and inspected for maintenance.
0cm1 and other gaskets of the accumulator 10 are replaced. After the maintenance and inspection of the instrumentation unit is completed, the valve device of the pressure gauge is opened, and the accumulator 10 is pumped again via the accumulator filling water pipe 36 by the pump (not shown).
Fill the inside with water to return the water pressure control unit to a usable state.

As shown in FIG. 6(D), when the angle valve 21 is fully opened, the spring receiving portion 25b of the valve shaft 25 is displaced in the direction of arrow x2 until it comes into contact with the valve body guide member 30, but the engagement does not occur. As the portion 25a is displaced from the neutral position in the x2 direction, it comes into contact with the flange portion 26d of the valve body 26 and separates the valve body 26 from the valve seat 27. That is, the gap between the valve body 26 and the valve seat 27 is made larger than that at the predetermined valve opening degree, so that the water in the accumulator 1O is quickly discharged. Therefore, when the water in the accumulator 10 is being drained, the angle valve 21 is fully opened to increase the amount of water drained, and the valve body 26 is returned to the predetermined valve opening position shown in FIG. 6(B) before the water is drained. , the water is drained in a short time without introducing air into the pipe 12.22 in the same way as in the above case.

As described above, according to the water pressure control unit of the present invention, when the drive water in the Akicomulator is discharged through the discharge valve that is opened to a predetermined valve opening degree, water is generated in the piping as the water pressure decreases. The valve body of the discharge valve is displaced by the force of the spring while the water is still filled, and the valve can be closed immediately. Therefore, it is possible to reliably prevent air from entering the drive water outflow piping, which is different from conventional methods. This eliminates the need for extra nerves when operating the handle when closing the discharge valve, and since the discharge valve closes itself, it can function within the limited space of equipment where piping is crowded. Furthermore, it has features such as being able to improve the reliability of the operating function during scram when the accumulator is filled with driving water again after the driving water has been discharged.

[Brief explanation of the drawing]

Figures 1 and 2.3 are piping diagrams and a side view and front view of a water pressure control unit to explain a general control rod drive control system for nuclear power generation, respectively, and Figure 4 is a water pressure control unit according to the present invention. Figure 5 is a vertical cross-sectional view of the angle valve which is the main part of the present invention, Figure 6 (A>, (B), (C), (D
) explains the function of the valve body part of the angle valve shown in Fig. 1.
FIG. 4-7.13...Selector valve, 8,9...Scrum valve for emergency control, 1O...Accumulator, 10a...
・Cylinder, 10b...N2 container, 1OC...Piston, 11, :121...Angle valve, 12...Drive water outflow piping, 25...Valve shaft, 25a...Engagement part,
26... Valve body, 26b... Chamber, 26d... Flange, 27... Valve seat, 28... Coil spring, 29...
Valve body. Figure 2 Third doctor

Claims (1)

[Claims] A scram valve that is opened during scram, an accumulator that supplies drive water to the control rod drive device through the opened scram valve, and a drive water outflow between the scram valve and the accumulator that communicates with the piping. and a discharge valve for discharging the driving water to the outside. The valve body is composed of a relatively movable valve body and an energizing means for biasing the valve body in the valve closing direction. A water pressure control unit characterized in that it is configured to be displaced to a position according to the pressure of driving water and the urging force of the urging means.