JP7591990B2 - Fuel lifting device - Google Patents

Description

This disclosure relates to a fuel tilting device that stands or tilts a container that holds nuclear fuel.

A nuclear power plant has a reactor installed inside a reactor containment vessel, and is also provided with a nuclear fuel transfer device. The nuclear fuel transfer device transfers nuclear fuel stored in a container between the reactor cavity and the spent fuel pit. The reactor cavity and the spent fuel pit are connected by a transfer pipe that penetrates the containment vessel bulkhead. For this reason, the nuclear fuel transfer device, for example, turns over nuclear fuel stored upright in the reactor cavity, and moves the turned over nuclear fuel to the spent fuel pit via the transfer pipe using a cart. The nuclear fuel transfer device then turns over the turned over nuclear fuel upright and stores it in the spent fuel pit.

The nuclear fuel transfer device has a fuel erecting device that turns upright nuclear fuel sideways and stands upright nuclear fuel that is lying down. An example of a conventional fuel erecting device is that described in Patent Document 1 below.

Patent No. 2755672

Conventional fuel erection devices use hydraulic cylinders to lay nuclear fuel on its side or erect it upright. This requires pumps and various valves to be installed in the water supply line that supplies water to the hydraulic cylinder and the drain line that drains water, resulting in a complex piping configuration. This results in the problem that maintenance work on the various devices takes a long time.

The present disclosure aims to solve the above-mentioned problems and provide a fuel lifting device that improves maintainability by simplifying the piping configuration.

To achieve the above object, the fuel raising and lowering device of the present disclosure includes a servo pump that supplies water, a hydraulic cylinder that can move the fuel between an upright position and a sideways position, a pair of supply and discharge paths that connect the servo pump and the hydraulic cylinder and supply and discharge water to operate the hydraulic cylinder, and a pair of speed control valves that are provided in each of the pair of supply and discharge paths.

The fuel lifting device disclosed herein can improve maintainability by simplifying the piping configuration.

FIG. 1 is a schematic diagram showing a fuel raising device according to the present embodiment. FIG. 2 is a graph showing the pump rotation speed when the fuel is turned over sideways. FIG. 3 is a graph showing the pump rotation speed when fuel is raised.

Below, a preferred embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the various embodiments. Furthermore, the components in the embodiments include those that a person skilled in the art would easily imagine, those that are substantially the same, and those that are within the so-called equivalent range.

<Configuration of the fuel lifting device>
FIG. 1 is a schematic diagram showing a fuel raising device according to the present embodiment.

As shown in FIG. 1, the fuel elevation device 10 constitutes a part of the nuclear fuel transfer device installed in the nuclear power plant. The nuclear fuel transfer device transfers nuclear fuel stored in a container between the reactor cavity and the spent fuel pit. The nuclear fuel transfer device uses the fuel elevation device 10 to tilt the nuclear fuel stored upright in the reactor cavity, moves the tilted nuclear fuel to the spent fuel pit through a transfer pipe by a cart, and erects the tilted nuclear fuel by the fuel elevation device 10 and stores it in the spent fuel pit. The nuclear fuel transfer device also uses the fuel elevation device 10 to tilt the nuclear fuel stored upright in the spent fuel pit, moves the tilted nuclear fuel to the reactor cavity through a transfer pipe by a cart, and erects the tilted nuclear fuel by the fuel elevation device 10 and stores it in the reactor cavity.

The fuel raising device 10 includes a servo pump 11, a hydraulic cylinder 12, a pair of supply and discharge paths L11, L12, and a pair of speed control valves 13, 14.

The hydraulic cylinder 12 has a cylinder 21, a piston 22, and a rod 23. The cylinder 21 is hollow, and the piston 22 is supported inside so that it can move freely along the axial direction. The cylinder 21 is divided into two chambers R1 and R2 by providing the piston 22 inside. One axial end of the rod 23 is connected to the piston 22, and the other axial end extends outside the cylinder 21. The other end of the rod 23 is connected to a connecting part 24.

The fuel F is stored in a container, but the container is not shown and will be described as fuel F. The fuel F is supported so that it can move freely between an upright state shown by a solid line in FIG. 1 and a sideways state shown by a two-dot chain line in FIG. 1. The fuel F is fixed at one axial end of the arm 25. The other axial end of the arm 25 is connected to the connecting part 24 so that it can rotate freely.

Therefore, when the fuel F is in an upright position, when water is supplied to the chamber R1 of the hydraulic cylinder 12 and the water is discharged from the chamber R2, the piston 22 advances axially to one side (the left side in FIG. 1). Then, the rod 23 of the hydraulic cylinder 12 extends, and the arm 25 rotates to one side (the left side in FIG. 1) via the connecting part 24. At this time, the fuel F integrated with the arm 25 moves from an upright position to a lying position.

On the other hand, when the fuel F is in a lying state, supplying water to the chamber R2 of the hydraulic cylinder 12 and discharging water from the chamber R1 causes the piston 22 to retreat to the other axial side (the right side in FIG. 1). Then, the rod 23 of the hydraulic cylinder 12 contracts, and the arm 25 rotates to the other side (the right side in FIG. 1) via the connecting part 24. At this time, the fuel F integrated with the arm 25 moves from the lying state to an upright state.

The hydraulic cylinder 12 has a supply/discharge port P1 in room R1 and a supply/discharge port P2 in room R2. One end of the supply/discharge path L11 is connected to the supply/discharge port P1, and one end of the supply/discharge path L12 is connected to the supply/discharge port P2. Here, the supply/discharge path L11 serves as a water supply path for advancing the piston 22 of the hydraulic cylinder 12, and serves as a water discharge path for retracting the piston 22. In addition, the supply/discharge path L12 serves as a water supply path for retracting the piston 22 of the hydraulic cylinder 12, and serves as a water discharge path for advancing the piston 22.

The supply and exhaust paths L11 and L12 are provided with speed control valves 13 and 14, respectively. The speed control valves 13 and 14 have throttle valves 13a and 14a provided in the main paths L11a and L12a of the supply and exhaust paths L11 and L12, respectively, and check valves 13b and 14b provided in the bypass paths L11b and L12b of the supply and exhaust paths L11 and L12, respectively. The throttle valves 13a and 14a limit the amount of water between the chambers R1 and R2 of the hydraulic cylinder 12 and the supply and exhaust paths L11 and L12. The check valves 13b and 14b prevent the flow of water in the chambers R1 and R2 of the hydraulic cylinder 12 from flowing to the supply and exhaust paths L11 and L12, and allow the flow of water in the supply and exhaust paths L11 and L12 from flowing to the chambers R1 and R2 of the hydraulic cylinder 12.

Therefore, when the piston 22 of the hydraulic cylinder 12 is advanced, water in the supply and discharge path L11 is supplied to the room R1, and water in the room R2 is discharged to the supply and discharge path L12. At this time, the throttle valve 13a and check valve 13b of the speed control valve 13 are open, and the flow rate (amount of water per unit time) of the water supplied from the supply and discharge path L11 to the room R1 is not restricted. On the other hand, the speed control valve 14 has only the throttle valve 14a open and the check valve 14b closed, so the flow rate (amount of water per unit time) of the water discharged from the room R2 to the supply and discharge path L12 decreases.

Similarly, when the piston 22 of the hydraulic cylinder 12 is retracted, water in the supply and discharge path L12 is supplied to the room R2, and water in the room R1 is discharged to the supply and discharge path L11. At this time, the throttle valve 14a and check valve 14b of the speed control valve 14 are open, and the flow rate (amount of water per unit time) of the water supplied from the supply and discharge path L12 to the room R2 is not limited. However, the speed control valve 13 has only the throttle valve 13a open and the check valve 13b closed, so the flow rate (amount of water per unit time) of the water discharged from the room R1 to the supply and discharge path L11 decreases.

The supply and exhaust paths L11 and L12 are provided with on-off valves 31 and 32, respectively. The on-off valves 31 and 32 are electromagnetic cut-off valves. That is, the on-off valves (electromagnetic cut-off valves) 31 and 32 are connected to a power supply unit. The on-off valves (electromagnetic cut-off valves) 31 and 32 are open when energized and closed when deenergized.

The supply and discharge paths L11 and L12 each have a servo pump 11 at the other end. The servo pump 11 has a servo motor 33 and an electric pump 34. The servo motor 33 is connected to a power supply unit. The servo motor 33 is driven by power supplied from the power supply unit, and drives the electric pump 34. When the electric pump 34 is driven, it supplies water from the supply and discharge path L11 or the supply and discharge path L12 toward the hydraulic cylinder 12. That is, when the servo motor 33 rotates forward, the electric pump 34 supplies water from the supply and discharge path L12 to the supply and discharge path L11. On the other hand, when the servo motor 33 rotates reversely, the electric pump 34 supplies water from the supply and discharge path L11 to the supply and discharge path L12.

The supply and discharge paths L11 and L12 are provided at the other end with a first bypass path L13 that bypasses the servo pump 11, and a second bypass path L14. The first bypass path L13 is connected to the water tank 35 by the first water supply path L15, and the second bypass path L14 is connected to the water tank 35 by the second water supply path L16. The first bypass path L13 is provided with check valves 36 and 37 on both sides of the connection part of the first water supply path L15. The check valves 36 and 37 allow water to flow from the connection part of the first water supply path L15 to the servo pump 11 side, and prevent water from flowing from the servo pump 11 to the connection part of the first water supply path L15. The second bypass path L14 is provided with relief valves 38 and 39 on both sides of the connection part of the second water supply path L16. The relief valves 38 and 39 open when the water pressure in the supply and exhaust paths L11 and L12 exceeds a preset limit pressure.

In addition, one end of a pair of emergency supply and exhaust paths L21, L22 is connected between the speed control valves 13, 14 and the on-off valves 31, 32 of the supply and exhaust paths L11, L12. A manual changeover valve 41 is connected to the other end of the pair of emergency supply and exhaust paths L21, L22. The manual changeover valve 41 is connected to a water tank 42 by a water supply path L23 and to the water tank 42 by a drainage path L24. The water tank 42 may also serve as the water tank 35.

Emergency supply and exhaust paths L21 and L22 are provided with on-off valves 43 and 44, respectively. On-off valves 43 and 44 are manually operated valves. That is, on-off valves 43 and 44 (manually operated valves) can be opened and closed by manual operation by an operator, and are normally closed.

The water supply path L23 is provided with a manual pump 45. The manual pump 45 is operated by an operator's manual operation, and can supply water from the water tank 42 to the water supply path L23. The manual switching valve 41 can manually switch the connection state between the emergency supply and drainage paths L21, L22 and the water supply path L23 and the drainage path L24. That is, when the emergency supply and drainage path L21 and the water supply path L23 are connected by the manual switching valve 41, and the emergency supply and drainage path L22 and the drainage path L24 are connected, the water in the water supply path L23 is supplied to the supply and drainage path L11 via the emergency supply and drainage path L21, and the water in the supply and drainage path L12 is discharged from the emergency supply and drainage path L22 to the drainage path L24. In addition, when the manual switching valve 41 connects the emergency supply and exhaust path L22 and the water supply path L23, and connects the emergency supply and exhaust path L21 and the drainage path L24, the water in the water supply path L23 is supplied to the supply and exhaust path L12 via the emergency supply and exhaust path L22, and the water in the supply and exhaust path L11 is discharged from the emergency supply and exhaust path L22 to the drainage path L24.

The servo pump 11 is connected to a control device 51, which can drive and control the servo pump 11. The control device 51 can control the rotation speed of the electric pump 34 by pattern-controlling the rotation speed of the servo motor 33. After increasing the rotation speed of the servo pump 11 to a preset specified rotation speed, the control device 51 maintains the specified rotation speed for a preset specified time, thereby operating the hydraulic cylinder 12 and moving the fuel F between an upright state and a sideways state.

<Operation of the fuel lifting device>
When the fuel F is changed from an upright state to a lateral state, the servo pump 11 is driven to supply water in the supply/discharge path L11 to the chamber R1 of the hydraulic cylinder 12, while discharging water in the chamber R2 to the supply/discharge path L12. Then, in the hydraulic cylinder 12, the piston 22 advances to one side in the axial direction (the left side in FIG. 1), and the rod 23 extends, rotating the arm 25 to one side (the left side in FIG. 1) via the connecting part 24. The fuel F integrated with the arm 25 rotates from the upright state to a lateral state.

When water in the supply/discharge path L11 is supplied to the chamber R1, the throttle valve 13a and check valve 13b of the speed control valve 13 are open, so that the water in the supply/discharge path L11 is supplied to the chamber R1 of the hydraulic cylinder 12 at a predetermined flow rate. On the other hand, when water in the chamber R2 is discharged to the supply/discharge path L12, the speed control valve 14 opens only the throttle valve 14a and closes the check valve 14b, so that the water in the chamber R2 is discharged to the supply/discharge path L12 at a low speed. This limits the speed at which the piston 22 advances, and the speed at which the fuel F moves decreases. As a result, the fuel F, which is in an upright position, slowly falls over to a sideways position.

On the other hand, when the fuel F is changed from a lying state to an upright state, the servo pump 11 is driven to supply water in the supply and discharge path L12 to the chamber R2 of the hydraulic cylinder 12, while discharging water from the chamber R1 to the supply and discharge path L11. Then, in the hydraulic cylinder 12, the piston 22 retreats to the other side in the axial direction (the right side in FIG. 1), and the rod 23 contracts, rotating the arm 25 to the other side (the right side in FIG. 1) via the connecting part 24. The fuel F integrated with the arm 25 rotates from a lying state to an upright state.

When water in the supply/discharge path L12 is supplied to the chamber R2, the throttle valve 14a and check valve 14b of the speed control valve 14 are open, so that the water in the supply/discharge path L12 is supplied to the chamber R2 of the hydraulic cylinder 12 at a predetermined flow rate. On the other hand, when water in the chamber R1 is discharged to the supply/discharge path L11, the speed control valve 13 opens only the throttle valve 13a and closes the check valve 13b, so that the water in the chamber R1 is discharged to the supply/discharge path L11 at a low speed. This limits the speed at which the piston 22 retreats, and the speed at which the fuel F moves decreases. As a result, the fuel F, which has been lying on its side, slowly becomes upright.

When the servo pump 11 supplies water from the supply and discharge path L11 to the room R1, the shortage of water is replenished with water from the water tank 35 via the first water supply path L15 and the first bypass path L13. When the servo pump 11 supplies water from the supply and discharge path L12 to the room R2, the shortage of water is replenished with water from the water tank 35 via the first water supply path L15 and the first bypass path L13.

Here, we will explain the control of the rotation speed of the servo pump 11 by the control device 51. Figure 2 is a graph showing the pump rotation speed when the fuel is turned over, and Figure 3 is a graph showing the pump rotation speed when the fuel is turned upright.

As shown in FIG. 2, when the fuel F is turned from an upright state to a lateral state, at time t1, the servo pump 11 starts to be driven and the rotation speed is increased. Here, the fuel F starts to be turned from the upright state to a lateral state. At time t2, when the rotation speed of the servo pump 11 reaches a predetermined rotation speed Nh ₁ , the rotation speed is maintained at the predetermined rotation speed Nh _1. Then, at time t3, when a predetermined time T1 has elapsed since the rotation speed Nh ₁ was reached at time t2, the rotation speed of the servo pump 11 is reduced. Then, at time t4, when the rotation speed of the servo pump 11 reaches a predetermined rotation speed Nl ₁ , the rotation speed is maintained at the predetermined rotation speed Nl _1. Here, the fuel F is turned to a lateral state, and the rotation speed of the servo pump 11 is maintained at the predetermined rotation speed Nl ₁ , thereby maintaining the fuel F in a lateral state.

As shown in FIG. 3, when the fuel F is changed from a lying state to a standing state, at time t11, the servo pump 11 starts to be driven and the rotation speed is increased. Here, the fuel F starts to stand up from the lying state. When the rotation speed of the servo pump 11 reaches a predetermined rotation speed _Nh2 at time t12, it is maintained at the predetermined rotation speed _Nh2 . The predetermined rotation speed _Nh2 during the standing up operation of the fuel F is set higher than the predetermined rotation speed _Nh1 during the lying down operation of the fuel F. Then, at time _t13 , when a predetermined time T2 has elapsed since the predetermined rotation speed _Nh2 was reached at time t12, the rotation speed of the servo pump 11 is reduced. Then, at time t14, when the rotation speed of the servo pump 11 reaches a predetermined rotation speed _Nl2 , it is maintained at the predetermined rotation speed _Nl2 . Here, the fuel F is in an upright state, and the upright state of the fuel F is maintained by maintaining the rotation speed of the servo pump 11 at a predetermined rotation speed Nl _2. Note that the predetermined rotation speed Nl ₁ when the fuel F is turned over and the predetermined rotation speed Nl ₂ when the fuel F is upright are set in advance by measuring the moving speed of the water pressure cylinder 12.

The servo motor 33 is driven by electricity obtained from the power supply unit, so if the power supply unit is damaged and loses power, the servo pump 11 cannot operate. In this case, the servo pump 11 stops supplying and discharging water to the hydraulic cylinder 12. If the servo pump 11 loses power and is operating the hydraulic cylinder 12 to move the fuel F, there is a risk that the fuel F will tip over.

At this time, the on-off valves 31 and 32 are maintained in an open state by receiving power from the power supply unit. Therefore, when power is lost, the on-off valves 31 and 32 close, blocking the connection between the hydraulic cylinder 12 and the servo pump 11 in the supply and discharge paths L11 and L12. The hydraulic cylinder 12 then stops supplying and discharging water between the chambers R1 and R2 and the supply and discharge paths L11 and L12, and the piston 22 is maintained in a stopped state. Therefore, even if the hydraulic cylinder 12 is operating and moving the fuel F, the movement of the fuel F is maintained, and the fuel F is prevented from tipping over.

Then, the worker operates the on-off valves 43 and 44 to open them. The worker also connects the emergency supply and exhaust path L21 and the water supply path L23, and the emergency supply and exhaust path L22 and the drain path L24, for example, using the manual switching valve 41. Then, the emergency supply and exhaust path L21 is connected to the supply and exhaust path L11, and the emergency supply and exhaust path L22 is connected to the supply and exhaust path L12. In this state, the worker operates the manual pump 45. Then, water from the water tank 42 is supplied to the supply and exhaust path L11 via the water supply path L23 and the emergency supply and exhaust path L21. Therefore, water from the supply and exhaust path L11 is supplied to the chamber R1 of the hydraulic cylinder 12, and water from the chamber R2 is discharged to the supply and exhaust path L12. Then, the piston 22 and the rod 23 of the hydraulic cylinder 12 move forward, and the arm 25 is rotated via the connecting part 24, allowing the fuel F to slowly fall over.

[Effects of this embodiment]
The fuel raising and lowering device of the first aspect comprises a servo pump 11 that supplies water, a hydraulic cylinder 12 that can move the fuel F between an upright position and a sideways position, a pair of supply and discharge paths L11, L12 that connect the servo pump 11 and the hydraulic cylinder 12 and supply and discharge water to operate the hydraulic cylinder 12, and a pair of speed control valves 13, 14 that are provided in the pair of supply and discharge paths L11, L12, respectively.

According to the fuel raising and lowering device of the first aspect, when the servo pump 11 is driven, water is supplied to the hydraulic cylinder 12 via a pair of supply and discharge paths L11, L12, and the fuel F can be moved between an upright state and a sideways state. At this time, the speed of the water supplied and discharged between the supply and discharge paths L11, L12 and the hydraulic cylinder 12 is adjusted by the speed control valves 13, 14. Therefore, by using the servo pump 11, for example, pattern control is possible, and the position of the fuel F can be controlled with high precision via the hydraulic cylinder 12, and the piping configuration can be simplified to improve maintainability. In addition, by using the speed control valves 13, 14, the speed of the upright movement and the sideways movement of the fuel F can be limited and reduced, thereby improving safety.

In the fuel raising/lowering device according to the second aspect, the pair of speed control valves 13, 14 reduce the flow rate of water in the direction in which water is discharged from the hydraulic cylinder 12 to the pair of supply/discharge paths L11, L12. As a result, when the fuel F is changed from an upright state to a sideways state, or from a sideways state to an upright state, the discharge of water from the hydraulic cylinder 12 is restricted to reduce the operating speed of the fuel F, thereby improving safety.

The fuel raising device according to the third aspect is provided with a pair of on-off valves 31, 32 that stop the flow of water in the pair of supply and discharge paths L11, L12 when the power source that drives the servo pump 11 is cut off. As a result, even if the servo pump 11 stops, the on-off valves 31, 32 stop the flow of water in the supply and discharge paths L11, L12, preventing the discharge of water from the servo pump 11 and preventing the fuel F from falling over due to the unexpected operation of the hydraulic cylinder 12.

The fuel raising/lowering device according to the fourth aspect is provided with a manual pump 45 that supplies and discharges water to and from a pair of supply and discharge paths L11 and L12 when the on-off valves 31 and 32 are activated. As a result, when the servo pump 11 stops, an operator can operate and drive the manual pump 45 to supply water to and operate the servo pump 11, thereby moving the fuel F to a lying or upright position.

The fuel raising and lowering device according to the fifth aspect is provided with a control device 51 that drives and controls the rotation speed of the servo pump 11. After the control device 51 increases the rotation speed to a preset predetermined speed, it maintains the preset rotation speed for a preset period of time, thereby operating the hydraulic cylinder 12 to move the fuel F between an upright state and a sideways state. This simplifies the operation control of the hydraulic cylinder 12 by the servo pump 11.

10 Fuel raising and lowering device 11 Servo pump 12 Hydraulic cylinder 13, 14 Speed control valve 13a, 14a Throttle valve 13b, 14b Check valve 21 Cylinder 22 Piston 23 Rod 24 Connection part 25 Arm 31, 32 Opening and closing valve 33 Servo motor 34 Electric pump 35 Water tank 36, 37 Check valve 38, 39 Relief valve 41 Manual switching valve 42 Water tank 43, 44 Opening and closing valve 45 Manual pump 51 Control device F Fuel L11, L12 Supply and exhaust path L11a, L12a Main path L11b, L12b Bypass path L13 First bypass path L14 Second bypass path L15 First water supply path L16 Second water supply path L21, L22 Emergency supply and exhaust route L23 Water supply route L24 Drainage route P1, P2 Supply and exhaust port R1, R2 Room

Claims (4)

A servo pump for supplying water;
A hydraulic cylinder capable of moving the fuel between an upright position and a sideways position;
a pair of supply and discharge paths connecting the servo pump and the water hydraulic cylinder and supplying and discharging water to operate the water hydraulic cylinder;
A pair of speed control valves provided in the pair of supply and exhaust paths, respectively;
A control device that drives and controls the rotation speed of the servo pump;
Equipped with
The control device starts the upright or sideways movement of the fuel by increasing the rotation speed of the servo pump, and after increasing to a preset high rotation speed, maintains the high rotation speed for a preset predetermined time, thereby operating the hydraulic cylinder to move the fuel between the upright state and the sideways state, and when the preset time has elapsed, reduces the rotation speed and maintains it at a preset low rotation speed, thereby maintaining the upright or sideways state of the fuel.
Fuel lift device. The pair of speed control valves reduce a flow velocity of water in a direction in which water is discharged from the water pressure cylinder to the pair of supply and discharge paths.
2. The fuel lift-off device of claim 1. a pair of on-off valves are provided to stop the flow of water in the pair of supply and discharge paths when a power source for driving the servo pump is cut off;
The fuel lifting device according to claim 1 or 2. A manual pump is provided to supply and discharge water to and from the pair of supply and discharge paths when the on-off valve is operated.
4. The fuel lift-off device according to claim 3.

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