Containment isolation valve operation device and method for operating containment isolation valve

Abstract

To provide a containment isolation valve operation device capable of mechanically and forcibly operating an isolation valve provided inside a reactor containment vessel by an operator outside the reactor containment vessel.SOLUTION: A containment isolation valve operation device includes: a drive shaft 1 mechanically connected to an isolation valve 101 provided on an inner side 100in of a reactor containment vessel 100 and extending to an outer side 100out of the reactor containment vessel 100 through a through-hole 103 penetrating the inside and the outside of the reactor containment vessel 100; and a grip part 2 mechanically connected to the drive shaft 1 on the outer side 100out of the reactor containment vessel 100, the grip part applying power to the drive shaft 1. Power is applied from the grip portion 2 to the drive shaft 1 and is transmitted to the isolation valve 101 via the drive shaft 1 to open and close the isolation valve 101.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for operating an isolation valve installed in a nuclear reactor containment vessel and a method for operating an isolation valve installed in a nuclear reactor containment vessel. [Background technology]

[0002] In nuclear power plants where steam is supplied from the reactor pressure vessel to the turbine building through piping, isolation valves installed in the piping are designed to close when an earthquake is detected in order to prevent a loss of coolant accident (LOCA).

[0003] When the isolation valves are closed, the temperature inside the reactor pressure vessel rises, making it necessary to cool the inside of the reactor pressure vessel. Meanwhile, the pressure inside the reactor pressure vessel also rises, so in order to inject cooling water into the reactor pressure vessel, it is necessary to reduce the pressure inside the reactor pressure vessel. For this reason, Patent Document 1, for example, discloses a device that forcibly opens the main steam safety relief valve inside the reactor containment vessel in order to reduce the pressure inside the reactor pressure vessel in the event of a blackout (SBO). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-87232 Summary of the Invention [Problem to be solved by the invention]

[0005] When an abnormal event occurs and the reactor cooling system is no longer able to cool the reactor, if the isolation valves of the equipment that cools the reactor (for example, the reactor core isolation cooling system and the emergency condenser system) are closed due to a malfunction of the control device, the reactor will lose its cooling function, and there is a risk of an accident that could lead to a serious accident or a major accident (hereinafter referred to as a major accident, etc.) occurring.

[0006] In order to deal with such an event, it is necessary for the operator to mechanically and forcibly open the closed isolation valves, and after the event has been resolved, it is necessary for the operator to mechanically and forcibly close the open isolation valves.

[0007] However, in order to mechanically and forcibly operate the isolation valves inside the reactor containment vessel, it is necessary for operators to operate the isolation valves inside the reactor containment vessel. In the event of a serious accident, it is not desirable to have operators enter the reactor containment vessel in order to ensure their safety, and it is difficult for operators to mechanically and forcibly operate the isolation valves inside the reactor containment vessel.

[0008] An object of the present invention is to provide an isolation valve actuation device inside a reactor containment vessel that can mechanically and forcibly actuate an isolation valve installed inside the reactor containment vessel by an operator outside the reactor containment vessel. [Means for solving the problem]

[0009] The present application includes a plurality of means for solving the above-mentioned problems. One example thereof includes a drive shaft that is mechanically connected to an isolation valve provided inside the reactor containment vessel and extends to the outside of the reactor containment vessel through a through-hole that penetrates the inside and outside of the reactor containment vessel, and a gripper that is mechanically connected to the starter shaft outside the reactor containment vessel and applies power to the drive shaft, and the power applied to the drive shaft from the gripper is transmitted to the isolation valve via the drive shaft to open and close the isolation valve. [Effects of the Invention]

[0010] According to the present invention, an isolation valve provided inside the reactor containment vessel and a gripper provided outside the reactor containment vessel are mechanically connected via a drive shaft, so that an operator can mechanically and forcibly operate the isolation valve provided inside the reactor containment vessel by operating the gripper provided outside the reactor containment vessel. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiment. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing an in-containment vessel isolation valve actuation device according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a schematic diagram showing an in-containment vessel isolation valve actuation device according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a schematic diagram showing an in-containment vessel isolation valve actuation device according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram showing an in-containment vessel isolation valve actuation device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The configurations and operations of in-containment isolation valve actuation devices according to first to fourth embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals in each drawing indicate the same parts.

[0013] (First embodiment) FIG. 1 is a schematic diagram showing an in-containment isolation valve actuation device 10 according to a first embodiment of the present invention.

[0014] The in-containment isolation valve actuation device 10 is a device for mechanically and forcibly actuating an isolation valve 101 provided inside 100in of the reactor containment vessel 100 by an operator outside 100out of the reactor containment vessel 100.

[0015] The reactor containment vessel 100 is a structure that surrounds the reactor and prevents leakage of radioactive materials.

[0016] The isolation valve 101 is a solenoid valve that opens and closes the flow path in the piping 102 in accordance with a signal transmitted from a control device. The isolation valve 101 in this embodiment is provided inside 100in of the reactor containment vessel 100, and not only opens and closes in accordance with a signal transmitted from the control device, but can also be forcibly opened and closed by an in-containment vessel isolation valve actuation device 10.

[0017] For example, the isolation valve 101 shown in FIG. 1 opens when energized and closes when de-energized, and can also be mechanically and forcibly switched from an open state to a closed state by the in-containment isolation valve actuation device 10.

[0018] It is preferable that the isolation valve 101 is provided in a system that cools the reactor when the reactor cooling system is no longer able to cool the reactor, for example, piping 102 of a reactor core isolation cooling system or an emergency condenser system.

[0019] The in-containment vessel isolation valve actuation device 10 is a device that is mechanically connected to an isolation valve 101 provided inside 100in of the reactor containment vessel 100 and is equipped with a drive shaft 1 that extends to the outside 100out of the reactor containment vessel 100 via a through hole 103 that penetrates the inside and outside of the reactor containment vessel 100, and a gripper 2 that is mechanically connected to the drive shaft 1 at the outside 100out of the reactor containment vessel 100 and applies power to the drive shaft 1, and the power applied to the drive shaft 1 from the gripper 2 is transmitted to the isolation valve 101 via the drive shaft 1, opening and closing the isolation valve 101.

[0020] In addition, in the method for operating an isolation valve inside a containment vessel according to this embodiment, an isolation valve 101 provided inside the reactor containment vessel 100 and a gripper 2 provided on the outside 100out of the reactor containment vessel 100 are mechanically connected by a drive shaft 1 via a through-hole 103 penetrating the inside and outside of the reactor containment vessel 100, and the operator operates the gripper 2 to forcibly open and close the isolation valve 101.

[0021] The drive shaft 1 is a component that mechanically transmits the operation of the gripper 2 by an operator to the isolation valve 101. The drive shaft 1 may be formed from a rod-shaped rigid body (for example, a steel round bar), or may be formed from a flexible shaft, for example, a flexible shaft in which a wire shaft is covered with a tube.

[0022] The drive shaft 1 may be mechanically connected to the isolation valve 101 such that the isolation valve 101 opens and closes when the drive shaft 1 is rotated in a circumferential direction of the drive shaft 1, or may be mechanically connected to the isolation valve 101 such that the isolation valve 101 opens and closes when the drive shaft 1 is moved in an axial direction of the drive shaft 1.

[0023] The gripping unit 2 is a part operated by an operator and may be a disk-shaped handle or a rod-shaped lever. The gripping unit 2 may be mechanically connected to the drive shaft 1 so that the drive shaft 1 rotates in the circumferential direction of the drive shaft 1 or moves in the axial direction of the drive shaft 1 when the operator rotates the gripping unit 2, which is a disk-shaped handle, in the circumferential direction. The gripping unit 2 may also be mechanically connected to the drive shaft 1 so that the drive shaft 1 rotates in the circumferential direction of the drive shaft 1 or moves in the axial direction of the drive shaft 1 when the operator moves one end of the gripping unit 2, which is a rod-shaped lever, in one direction.

[0024] The through-hole 103 is a hole that penetrates the containment vessel 100 to allow the drive shaft 1, which is mechanically connected to the isolation valve 101, to extend from the inside 100 in of the containment vessel 100 to the outside 100 out. A seal is provided between the through-hole 103 and the drive shaft 1 to prevent radioactive materials from leaking from the inside 100 in of the containment vessel 100 to the outside 100 out.

[0025] [Actions and Effects] Nuclear power plants, which are constructed as design-based facilities that can adequately withstand earthquake forces, are equipped with isolation valves in their piping that automatically close when a rupture is detected. However, it has been pointed out that this can be a cause of serious accidents.

[0026] For example, the isolation valve 101 of the isolation condenser system installed in a facility subject to design standards is controlled by a control device so as to automatically close if a rupture in pipe 102 is detected. However, in the accident at the Fukushima Daiichi Nuclear Power Plant, it has been pointed out that the control device mistakenly detected a loss of DC power as a rupture in pipe 102 and automatically closed the isolation valve 101, which may have led to a loss of the reactor cooling function of the isolation condenser system and a serious accident.

[0027] In a nuclear power plant equipped with the containment vessel isolation valve actuation device 10 of this embodiment, if it is determined that the opening and closing (e.g., closing) of the isolation valve 101 by the control device may cause a serious accident, etc., the operator operates the gripper 2 provided on the outside 100out of the reactor containment vessel 100, and opens and closes (e.g., opens) the isolation valve 101, which is mechanically connected to the gripper 2 via the drive shaft 1, so as to prevent a serious accident, etc. from occurring.

[0028] That is, the in-containment vessel isolation valve actuation device 10 of this embodiment is equipped with a drive shaft 1 that is mechanically connected to an isolation valve 101 provided inside 100in of the reactor containment vessel 100 and extends to the outside 100out of the reactor containment vessel 100 via a through hole 103 that penetrates the inside and outside of the reactor containment vessel 100, and a gripper 2 that is mechanically connected to the drive shaft 1 at the outside 100out of the reactor containment vessel 100 and applies power to the drive shaft 1, and the power applied to the drive shaft 1 from the gripper 2 is transmitted to the isolation valve 101 via the drive shaft 1 to open and close the isolation valve 101.

[0029] As a result, even if a situation arises in which the opening and closing of the isolation valve 101 could cause a serious accident or the like (for example, a situation in which the isolation valve 101 inside 100in of the reactor containment vessel 100 malfunctions due to an erroneous detection by the control device, causing a serious accident or the like), the containment vessel isolation valve actuation device 10 of this embodiment can have the operator open and close the isolation valve 101 from outside 100out of the reactor containment vessel 100 to prevent a serious accident or the like from occurring.

[0030] For example, in a containment vessel isolation valve actuation device 10 in which a drive shaft 1 is mechanically connected to an isolation valve 101 provided in piping 102 of a reactor core isolation cooling system or an emergency condenser system, even if the control device mistakenly detects a loss of DC power as a rupture in the piping 102 and automatically closes the isolation valve 101, an operator can operate the gripping part 2 from the outside 100out of the reactor containment vessel 100 to mechanically and forcibly open the isolation valve 101, thereby preventing the occurrence of a serious accident, etc.

[0031] Furthermore, it is preferable that the drive shaft 1 be formed of a flexible shaft, for example, so that the isolation valve 101 and the gripping unit 2 can be mechanically connected by the drive shaft 1 even if the isolation valve 101, the through-hole 103, and the gripping unit 2 are not arranged in a straight line.

[0032] (Second embodiment) 2 is a schematic diagram of an in-containment isolation valve actuation device 20 according to a second embodiment of the present invention. The in-containment isolation valve actuation device 20 according to this embodiment differs from the in-containment isolation valve actuation device 10 according to the first embodiment in that the drive shaft 1 is formed from multiple shafts (in this embodiment, shafts 1a and 1b), and two of the multiple shafts, shafts 1a and 1b adjacent to each other in the axial direction of the drive shaft 1, are mechanically connected via an amplification mechanism 21 that amplifies the power applied to the drive shaft 1 from the gripper 2.

[0033] The amplifying mechanism 21 is, for example, a reducer or a hydraulic cylinder. The power (the rotational force in the circumferential direction of the drive shaft 1 or the thrust force in the axial direction of the drive shaft 1) applied to the drive shaft 1 from the gripper 2 is amplified by the amplifying mechanism 21 and transmitted to the shaft 1b.

[0034] [effect] In the in-containment isolation valve actuation device 20 of this embodiment, the drive shaft 1 is formed from a plurality of shafts, and of the plurality of shafts, two shafts 1a, 1b adjacent in the axial direction of the drive shaft 1 are mechanically connected via an amplification mechanism 21 that amplifies the power applied from the gripper 2 to the shaft 1a on the gripper 2 side. This reduces the force that must be applied to the gripper 2 to open and close the isolation valve 101, allowing the operator to open and close the isolation valve 101 easily.

[0035] (Third embodiment) 3 is a schematic diagram of an in-containment isolation valve actuation device 30 according to a third embodiment of the present invention. The in-containment isolation valve actuation device 30 according to this embodiment differs from the in-containment isolation valve actuation device 10 according to the first embodiment in that it is provided with a detachment mechanism 31 that enables the outside-containment drive shaft section 1c, which is the portion of the drive shaft 1 that extends from the through-hole 103 to the outside 100out of the reactor containment vessel 100, to be detached from the drive shaft 1, and that it is provided with a cover 32 that closes the outer opening of the through-hole 103 when the outside-containment drive shaft section 1c is detached from the drive shaft 1 by the detachment mechanism 31.

[0036] The detachment mechanism 31 is formed, for example, by a screw portion provided at the tip of the drive shaft portion 1c outside the containment vessel and a screw hole provided on the tip surface of the drive shaft portion 1d inside the containment vessel, which extends from the inside 100in of the reactor containment vessel 100 into the through-hole 103.

[0037] The lid 32 is, for example, a metal disk that is removably attached with multiple bolts to a flange (not shown) that surrounds the outer opening of the through-hole 103, and prevents leakage of radioactive materials from the inside 100 inches of the reactor containment vessel 100.

[0038] For example, in the event of a serious accident, the containment vessel isolation valve actuation device 30 is operated by an operator who removes the cover 32 that blocks the outer opening of the through-hole 103, attaches the outside containment vessel drive shaft 1c to the detachment mechanism 31, and operates the gripper 2 that is mechanically connected to the isolation valve 101 via the drive shaft 1, thereby forcibly opening and closing the isolation valve 101.

[0039] In addition, unless a serious accident has occurred, the operator removes the drive shaft portion 1 c outside the containment vessel from the detachment mechanism 31 and attaches the lid 32 to the flange surrounding the outer opening of the through-hole 103 .

[0040] [effect] The in-containment isolation valve actuation device 30 of this embodiment is provided with a detachment mechanism 31 that enables the outside-containment-vessel drive shaft section 1c, which is the section of the drive shaft 1 that extends from the through-hole 103 to the outside 100out of the reactor containment vessel 100, to be detached from the drive shaft 1. As a result, in the event of no serious accident, the outside-containment-vessel drive shaft section 1c can be removed from the drive shaft 1 by the detachment mechanism 31, preventing an operator from accidentally operating the gripping section 2 and forcibly opening or closing the isolation valve 101.

[0041] Furthermore, the in-containment isolation valve actuation device 30 of this embodiment is provided with a lid 32 that closes the outer opening of the through-hole 103 when the outside-containment drive shaft 1c is detached from the drive shaft 1. As a result, in the absence of a serious accident, the outside opening of the through-hole 103 can be closed with the lid 32 when the outside-containment drive shaft 1c is detached from the drive shaft 1, making it possible to secure the containment vessel boundary and suppress the leakage of radioactive materials.

[0042] Furthermore, in the case of a serious accident or the like, the in-containment vessel isolation valve actuation device 30 of this embodiment has an operator remove the cover 32 that closes the outer opening of the through-hole 103, attach the outer-containment vessel drive shaft 1c to the detachment mechanism 31, and operate the gripper 2 that is mechanically connected to the isolation valve 101 via the drive shaft 1, thereby forcibly opening and closing the isolation valve 101. This allows the operator to forcibly open and close the isolation valve 101 from the outside 100out of the reactor containment vessel 100 to prevent a serious accident or the like from occurring.

[0043] (Fourth embodiment) 4 is a schematic diagram of an in-containment isolation valve actuation device 40 according to a fourth embodiment of the present invention. The in-containment isolation valve actuation device 40 according to this embodiment differs from the in-containment isolation valve actuation device 10 according to the first embodiment in that it includes a non-flammable fluid injection mechanism 42 that injects a non-flammable fluid into a gap 41 between the through-hole 103 and the drive shaft 1.

[0044] The non-flammable fluid injection mechanism 42 is a mechanism that injects a non-flammable fluid (for example, nitrogen gas) into the gap 41 between the through-hole 103 and the drive shaft 1 to suppress leakage of radioactive materials from the inside 100 in of the containment vessel 100.

[0045] The non-flammable fluid injection mechanism 42 preferably includes a non-flammable fluid supply unit 42 a that supplies the non-flammable fluid, and a pipe 42 b that connects the non-flammable fluid supply unit 42 a and the gap 41 .

[0046] The non-flammable fluid supply unit 42a is, for example, a nitrogen gas cylinder.

[0047] The pipe 42b is a flow path for injecting the non-flammable fluid supplied from the non-flammable fluid supply unit 42a into the gap 41. The pipe 42b is preferably equipped with a self-actuating control valve 42c that automatically adjusts the valve opening so that the pressure of the non-flammable fluid is maintained at a predetermined pressure.

[0048] The piping 42b to which the self-acting control valve 42c is attached is formed by an upstream piping 42d that connects the non-flammable fluid supply section 42a and the self-acting control valve 42c, and a downstream piping 42e that connects the self-acting control valve 42c and the gap 41.

[0049] The upstream pipe 42d is preferably provided with a gate valve 42f, so that the non-flammable fluid supplied from the non-flammable fluid supply unit 42a to the upstream pipe 42d can be controlled by the gate valve 42f.

[0050] Furthermore, it is preferable that two gate valves 42f are provided in the downstream piping 42e, so that even if radioactive material inside 100 inches of the containment vessel 100 leaks from the gap 41 to the downstream piping 42e, the two gate valves 42f can block the leakage, thereby ensuring the containment vessel boundary and suppressing the leakage of radioactive material.

[0051] Furthermore, the downstream piping 42e preferably has a flange 42g for separating the downstream piping 42e provided between the upstream gate valve 42f (on the self-operated control valve 42c side) of the two gate valves 42f and the self-operated control valve 42c. This allows the downstream piping 42e to be separated into a first downstream piping 42h from the self-operated control valve 42c to the flange 42g, and a second downstream piping 42i from the flange 42g to the gap 41 between the through-hole 103 and the drive shaft 1. Therefore, when the in-containment vessel isolation valve actuation device 40 is not used due to reasons such as a serious accident, the first downstream piping 42h can be separated from the flange 42g and the second downstream piping 42i can be covered with a lid or the like, thereby preventing leakage of radioactive materials and ensuring the containment vessel boundary.

[0052] [effect] The containment vessel isolation valve actuation device 40 of this embodiment is equipped with a non-flammable fluid injection mechanism 42 that injects a non-flammable fluid into the gap 41 between the through hole 103 and the drive shaft 1, thereby preventing radioactive materials from leaking from the gap 41 between the through hole 103 and the drive shaft 1.

[0053] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0054] 1...drive shaft, 1a, 1b...shaft, 1c...drive shaft portion outside containment vessel, 2...gripping portion, 10, 20, 30, 40...isolation valve operating device inside containment vessel, 21...amplification mechanism, 31...detachment mechanism, 32...lid, 41...gap between penetration hole and drive shaft, 42...non-flammable fluid injection mechanism, 100...reactor containment vessel, inside...100in, outside...100out, 101...isolation valve, 103...penetration hole

Claims

1. a drive shaft that is mechanically connected to an isolation valve provided inside the reactor containment vessel and that extends to the outside of the reactor containment vessel through a through-hole that penetrates the inside and outside of the reactor containment vessel; a gripper mechanically connected to the drive shaft outside the containment vessel and applying power to the drive shaft; 1. An in-containment isolation valve actuation device, wherein power applied to the drive shaft from the gripper is transmitted to the isolation valve via the drive shaft to open and close the isolation valve.

2. The in-containment isolation valve actuation device according to claim 1, The drive shaft is formed from a plurality of shafts, The isolation valve actuation device in the containment vessel, characterized in that two of the plurality of shafts that are adjacent to each other in the axial direction of the drive shaft are mechanically connected via an amplification mechanism that amplifies the power applied to the drive shaft from the gripper.

3. The in-containment isolation valve actuation device according to claim 1, an attachment / detachment mechanism for attaching / detaching an outer-containment-vessel drive shaft portion, which is a portion of the drive shaft that extends from the through hole to the outside of the reactor containment vessel, from the drive shaft.

4. The in-containment isolation valve actuation device according to claim 3, and a lid that closes an outer opening of the through-hole when the drive shaft outside the containment vessel is detached from the drive shaft by the detachment mechanism.

5. The in-containment isolation valve actuation device according to claim 4, The cover that closes the outer opening of the through hole is removed, the external containment vessel drive shaft is attached to the detachment mechanism; an in-containment isolation valve actuation device for forcibly opening and closing the isolation valve by operating the gripper mechanically connected to the isolation valve via the drive shaft.

6. The in-containment isolation valve actuation device according to claim 1, an in-containment vessel isolation valve actuation device comprising a non-flammable fluid injection mechanism that injects a non-flammable fluid into a gap between the through hole and the drive shaft;

7. The in-containment isolation valve actuation device according to claim 1, 10. An in-containment vessel isolation valve actuation device, wherein the drive shaft is formed by a flexible shaft.

8. The in-containment isolation valve actuation device according to claim 1, 10. An in-containment vessel isolation valve actuation device, wherein the isolation valve is provided in piping of a reactor core isolation cooling system or an isolation condenser system.

9. an isolation valve provided inside the reactor containment vessel and a gripping portion provided outside the reactor containment vessel are mechanically connected by a drive shaft via a through hole that penetrates the inside and outside of the reactor containment vessel; A method for operating an isolation valve in a containment vessel, comprising the steps of: an operator operating the gripping portion to forcibly open or close the isolation valve.

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