Oil dampers and vibration control systems in nuclear reactor containment vessels

Abstract

To provide a technique of allowing an oil damper to exercise a sufficient function in a nuclear reactor storage container under a severe accident condition.SOLUTION: An oil damper 100 in a nuclear reactor storage container includes: a cylinder body 1a which defines a cylinder chamber CH for storing hydraulic oil 10a; and a piston 2 arranged in the cylinder chamber CH. Gas G generated in the cylinder chamber CH when the hydraulic oil 10a is exposed to radiation is discharged to the outside of the cylinder chamber CH. Alternatively, the hydraulic oil 10a is formed of radiation-resistant hydraulic oil to prevent generation of gas even when the hydraulic oil 10a is exposed to radiation.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] An embodiment of the present invention relates to an oil damper in a nuclear reactor containment vessel and a vibration control system. [Background technology]

[0002] The reactor containment vessel and its associated equipment are facilities of high seismic importance, and in seismic evaluation under the new regulatory standards, evaluation is required not only for seismic forces that have increased since construction, but also for severe accident conditions. Furthermore, additional measures will be required for associated equipment for which sufficient margins are not ensured in seismic evaluation under the new regulatory standards. One approach to improving seismic margins is to carry out construction to reinforce the structural strength, but much of the equipment associated with the reactor containment vessel is structurally infeasible to reinforce. For equipment that is difficult to reinforce, it is necessary to reduce the seismic forces acting on the equipment using vibration control devices such as oil dampers.

[0003] As a related technique, a seismic isolation structure is disclosed in Patent Document 1. The seismic isolation structure described in Patent Document 1 employs a technique for absorbing earthquake energy by oil dampers (in other words, a technique for damping vibrations caused by earthquake forces) for the purpose of improving the seismic margin of the equipment installed inside the reactor containment vessel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-37789 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the seismic isolation structure described in Patent Document 1, the seismic energy acting on the equipment in the reactor containment vessel is absorbed by the oil damper, but Patent Document 1 does not describe the suitability of the oil damper in the reactor containment vessel under severe accident conditions. In the event of a severe accident, it is assumed that the inside of the reactor containment vessel will be an environment of high temperature, high pressure, and high radiation. However, the hydraulic oil used in general oil dampers decomposes due to radiation exposure, generating gas inside the oil damper. The gas generated inside the oil damper absorbs the displacement acting on the oil damper and prevents the oil damper from performing its damping function. Therefore, in the reactor containment vessel under severe accident conditions, there is a possibility that the oil damper will not be able to perform its full function, but in the seismic isolation structure described in Patent Document 1, no measures are taken to enable the oil damper to perform its full function even under such conditions.

[0006] Furthermore, when the action of a large seismic force is expected, a larger damping function is required, and it becomes necessary to apply a large oil damper. However, in the seismic isolation structure described in Patent Document 1, it is not assumed that a large oil damper will be applied to the narrow space inside the reactor containment vessel. In particular, when applying a large oil damper inside the reactor containment vessel of an existing nuclear power plant, placement in the narrow space becomes an issue. Therefore, when placing a large oil damper in a narrow space, in addition to the issue of application under the severe accident conditions described above, it is necessary to consider downsizing the large oil damper.

[0007] In view of the above, an object of the present invention is to provide a technique that enables an oil damper to fully function inside a reactor containment vessel under severe accident conditions. [Means for solving the problem]

[0008] In order to solve the above problems, an oil damper for use in a reactor containment vessel according to an embodiment includes a cylinder body defining a cylinder chamber for accommodating hydraulic oil, a piston disposed in the cylinder chamber, and a reservoir tank fluidly connected to the cylinder chamber and configured to receive gas generated within the cylinder chamber; and a check valve configured to prevent the hydraulic oil from moving from the cylinder chamber toward the reservoir tank.and a gas generated in the cylinder chamber when the hydraulic oil is exposed to radiation is discharged to the outside of the cylinder chamber. The check valve is disposed at a position higher than the cylinder chamber and lower than the reservoir tank, and is configured such that, when the check valve is in an open state, gas generated in the cylinder chamber moves to the reservoir tank via the check valve. It is characterized by: In another embodiment, an oil damper inside a reactor containment vessel includes a cylinder body defining a cylinder chamber that contains hydraulic oil, and a piston disposed in the cylinder chamber, and is characterized in that the hydraulic oil is composed of a polyphenyl ether-based radiation-resistant hydraulic oil so that substantial gas generation is prevented even when the hydraulic oil is exposed to radiation.

[0009] A vibration control system according to an embodiment includes the above-mentioned oil damper in the containment vessel, and a displacement amplification mechanism that amplifies a displacement of a vibration control target device that is vibration controlled by the oil damper in the containment vessel, The displacement amplifying mechanism amplifies the displacement of the vibration-damping target device, thereby suppressing a decrease in the damping effect caused by the gas present in the cylinder chamber. It is characterized by: Effect of the Invention

[0010] According to an embodiment of the present invention, a technique can be provided that enables an oil damper to perform adequately within a reactor containment vessel under severe accident conditions. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an oil damper in a containment vessel according to a first embodiment. [Diagram 2] FIG. 2 is a schematic side view showing an example of a layout relationship between the oil damper in the reactor containment vessel and the equipment to be damped and the support structure in the reactor containment vessel according to the embodiment. [Diagram 3] FIG. 3 is a cross-sectional view that illustrates an example of the shape of a piston ring. [Figure 4] FIG. 4 is a diagram showing a schematic diagram of gas movement when an earthquake force acts on the oil damper inside the containment vessel in the first embodiment. [Diagram 5] FIG. 5 is a diagram showing a schematic diagram of gas movement when an earthquake force acts on the oil damper inside the containment vessel in the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the configuration of an oil damper in a containment vessel according to the second embodiment. [Figure 7] FIG. 7 is a schematic diagram showing the configuration of an oil damper in a containment vessel according to the third embodiment. [Figure 8] FIG. 8 is a schematic side view showing an example of a connection relationship between an oil damper in a reactor containment vessel, a vibration-control target device, and a displacement amplification mechanism in an embodiment, where (a) shows a state before an earthquake force acts, and (b) shows a state after the earthquake force acts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the oil damper 100 in the reactor containment vessel and the vibration control system 200 according to the embodiment will be described with reference to the accompanying drawings. In the following description, the same reference numerals are used for members and parts having the same functions, and repeated description of the members and parts to which the same reference numerals are used will be omitted.

[0013] (First embodiment) An oil damper 100A in a containment vessel according to a first embodiment will be described with reference to Figs. 1 to 5. Fig. 1 is a schematic diagram showing the configuration of the oil damper 100A in a containment vessel according to a first embodiment. Fig. 2 is a schematic side view showing an example of the arrangement relationship between the oil damper 100 in a containment vessel according to an embodiment, and the vibration-damping target equipment 13 and the support structure 14 in the containment vessel. Fig. 3 is a cross-sectional view showing an example of the shape of the piston ring 3. Figs. 4 and 5 are schematic views showing the movement of gas G when an earthquake force acts on the oil damper 100A in a containment vessel according to the first embodiment. In Figs. 4 and 5, the movement of gas is indicated by dashed arrows.

[0014] (composition) As illustrated in FIG. 1, an oil damper 100A for use in a containment vessel according to the first embodiment includes a cylinder body 1a, a piston 2, and a discharge hole H.

[0015] The cylinder body 1a defines a cylinder chamber CH that accommodates hydraulic oil 10a. The piston 2 is disposed within the cylinder chamber CH. The exhaust hole H exhausts gas generated within the cylinder chamber CH to the outside of the cylinder chamber CH.

[0016] (action) The hydraulic oil 10a moves in the cylinder chamber CH in response to the relative movement of the piston 2 with respect to the cylinder body 1a. In this way, the vibration of the piston 2 with respect to the cylinder body 1a is damped. In addition, when the hydraulic oil 10a is exposed to radiation, gas is generated from the hydraulic oil 10a in the cylinder chamber CH. The gas generated in the cylinder chamber CH is discharged to the outside of the cylinder chamber CH through the discharge hole H.

[0017] (effect) In the first embodiment, gas generated in the cylinder chamber CH when the hydraulic oil 10a is exposed to radiation is discharged to the outside of the cylinder chamber CH. Therefore, gas generated from the hydraulic oil 10a due to radiation irradiation does not remain in the cylinder chamber CH, and the cylinder chamber CH can be kept filled with the hydraulic oil 10a. Therefore, the oil damper 100A in the reactor containment vessel in the first embodiment can exhibit a sufficient damping function in the reactor containment vessel under severe accident conditions, similar to under normal conditions.

[0018] Next, optional additional configurations that can be adopted in the first embodiment (or the third or fourth embodiment described later) will be described with reference to FIGS. 1 to 5.

[0019] (Reservoir Tank 6) 1, the oil damper 100A in the containment vessel includes a reservoir tank 6. The reservoir tank 6 is fluidly connected to the cylinder chamber CH and receives gas generated in the cylinder chamber CH. The reservoir tank 6 is preferably disposed at a position higher than the cylinder chamber CH so that the gas generated in the cylinder chamber CH can smoothly move from the cylinder chamber CH to the reservoir tank 6.

[0020] When the oil damper 100A in the containment vessel includes the reservoir tank 6, gas generated from the hydraulic oil 10a due to radiation irradiation can be moved into the reservoir tank 6. Therefore, under severe accident conditions, the cylinder chamber CH can be kept filled with the hydraulic oil 10a.

[0021] In the example shown in FIG. 1, the reservoir tank 6 has a communication hole 6h that communicates the inside and outside of the reservoir tank 6. Furthermore, oil 10b is stored in the reservoir tank 6. In the example shown in FIG. 1, the oil 10b in the reservoir tank 6 is oil having the same components as the hydraulic oil 10a in the cylinder chamber CH. In this specification, in order to formally distinguish between the oil in the reservoir tank 6 and the oil in the cylinder chamber CH (i.e., the oil that contributes to vibration damping), the former is referred to as "oil 10b" and the latter is referred to as "hydraulic oil 10a."

[0022] In the reservoir tank 6, the space SP in which the oil 10b is stored may be a space whose volume is variable. In the example shown in FIG. 1, the reservoir tank 6 has a tank body 6a and a second piston 8 disposed in the tank body 6a. When the second piston 8 moves in a direction toward the communication hole 6h, the volume of the above-mentioned space SP decreases. When the second piston 8 moves in a direction away from the communication hole 6h, the volume of the above-mentioned space SP increases.

[0023] The reservoir tank 6 may have a biasing member (more specifically, a spring 9) that biases the second piston 8 in a direction toward the communication hole 6h. When the reservoir tank 6 has a biasing member that biases the second piston 8, a pre-pressure is applied to the oil 10b in the space SP by the biasing member.

[0024] (Cylinder 1, vibration control target device 13, and support structure 14) As illustrated in Fig. 1, the oil damper 100A in the containment vessel includes a cylinder 1. The cylinder 1 includes a cylinder body 1a that defines a cylinder chamber CH, a piston 2 that is disposed in the cylinder chamber CH, and a piston rod 12 that is connected to the piston 2. In the example illustrated in Fig. 1, the cylinder body 1a includes a first connection portion 11a (more specifically, a cylinder cover ear), and the piston rod 12 includes a second connection portion 12a.

[0025] In the example shown in FIG. 2, the cylinder body 1a (more specifically, the first connection part 11a) is connected to the vibration-damping target device 13 in the containment vessel, and the piston rod 12 (more specifically, the second connection part 12a) is connected to the support structure 14. In this way, the vibration-damping target device 13 is connected to the support structure 14 via the oil damper 100 in the containment vessel. Alternatively, the cylinder body 1a (more specifically, the first connection part 11a) may be connected to the support structure 14, and the piston rod 12 (more specifically, the second connection part 12a) may be connected to the vibration-damping target device 13 in the containment vessel. The support structure 14 may be any structure as long as it is a support structure in the containment vessel. The support structure 14 may be a wall part of the containment vessel or another structure. The vibration-damping target device 13 may be a reactor pressure vessel or another device.

[0026] (Check valve 7) 1, the oil damper 100A inside the containment vessel includes a check valve 7. The check valve 7 prevents the hydraulic oil 10a from moving from the cylinder chamber CH toward the reservoir tank 6. The check valve 7 keeps the hydraulic oil 10a in the cylinder chamber CH, thereby effectively damping the vibration of the piston 2 relative to the cylinder body 1a.

[0027] 1, the check valve 7 is disposed at a position higher than the cylinder chamber CH and lower than the reservoir tank 6. In this case, when the check valve 7 is in an open state, gas generated in the cylinder chamber CH smoothly moves from the cylinder chamber CH to the reservoir tank 6 via the check valve 7.

[0028] (First cylinder chamber CH1, second cylinder chamber CH2, and gas communication portion 21) 1, the cylinder 1 (more specifically, the cylinder chamber CH) includes a first cylinder chamber CH1 arranged on one side of the piston 2 and a second cylinder chamber CH2 arranged on the other side of the piston 2. More specifically, the cylinder chamber CH is partitioned by the piston 2, so that the first cylinder chamber CH1 is formed on one side of the piston 2 and the second cylinder chamber CH2 is formed on the other side of the piston 2.

[0029] 1, the cylinder 1 (more specifically, the cylinder chamber CH) has a gas communication part 21 disposed at an upper end of the cylinder chamber CH. The gas communication part 21 allows gas generated in the cylinder chamber CH to move between the first cylinder chamber CH1 and the second cylinder chamber CH2.

[0030] In the example shown in Fig. 1, a piston ring 3 is attached to the outer circumferential surface of the piston 2. As shown in Fig. 3, the piston ring 3 may be formed with an opening 3h that allows gas to pass through. The opening 3h is disposed on the upper end side of the cylinder chamber CH, so that the opening 3h of the piston ring 3 functions as a part of the gas communication part 21. More specifically, the gap between the piston 2 and the cylinder body 1a and the opening 3h of the piston ring 3 function as the gas communication part 21 disposed at the upper end of the cylinder chamber CH.

[0031] When the cylinder chamber CH has the gas communication part 21, gas generated in the spaces on both sides of the cylinder chamber CH partitioned by the piston 2 (in other words, gas generated in the first cylinder chamber CH1 and the second cylinder chamber CH2) can move between the spaces on both sides through the gas communication part 21. Therefore, gas G generated in the cylinder chamber CH can be discharged to the outside of the cylinder chamber CH through the check valve 7 from the space on the side not pressurized by the piston 2 when the piston 2 moves (see the dashed arrow in FIG. 4).

[0032] (Oil damper 100A inside nuclear reactor containment vessel) With reference to FIG. 1, an example of the oil damper 100A in a containment vessel according to the first embodiment will be described in more detail.

[0033] In the example shown in FIG. 1, an oil damper 100A in a containment vessel includes a cylinder 1, a reservoir tank 6, and a pipe 5. The oil damper 100A in the containment vessel includes a cylinder 1, a reservoir tank 6, and a pipe 5.

[0034] The cylinder 1 has a cylinder body 1a that defines a cylinder chamber CH that accommodates hydraulic oil 10a, and a piston 2 that is disposed in the cylinder chamber CH. The cylinder 1 includes a first cylinder chamber CH1 that is disposed on one side of the piston 2, and a second cylinder chamber CH2 that is disposed on the other side of the piston 2. The piston 2 separates the first cylinder chamber CH1 from the second cylinder chamber CH2.

[0035] In the example shown in FIG. 1, the cylinder 1 has a piston rod 12 and a piston ring 3. The piston rod 12 is connected to a piston 2, and the piston ring 3 is attached to the outer circumferential surface of the piston 2. The piston 2 contacts the inner wall of the cylinder body 1a via the piston ring 3. In the example shown in FIG. 1, an opening 3h (see FIG. 3 if necessary) is formed at the upper end of the piston ring 3.

[0036] The cylinder 1 has a communication part 23 that allows the hydraulic oil 10a to move between the first cylinder chamber CH1 and the second cylinder chamber CH2. More specifically, a through hole part 23h is formed in the piston 2, and the through hole part 23h functions as the communication part 23 that communicates the first cylinder chamber CH1 and the second cylinder chamber CH2. The communication part 23 is preferably a communication part separate from the gas communication part 21 described above.

[0037] In the example shown in Fig. 1, when the piston 2 moves in a direction toward the first cylinder chamber CH1, the first cylinder chamber CH1 is pressurized and the second cylinder chamber CH2 is depressurized. As a result, a part of the hydraulic oil 10a moves from the first cylinder chamber CH1 to the second cylinder chamber CH2. On the other hand, when the piston 2 moves in a direction toward the second cylinder chamber CH2, the second cylinder chamber CH2 is pressurized and the first cylinder chamber CH1 is depressurized. As a result, a part of the hydraulic oil 10a moves from the second cylinder chamber CH2 to the first cylinder chamber CH1.

[0038] In the example shown in FIG. 1, the cylinder 1 has a first discharge hole H1 formed in a wall defining the first cylinder chamber CH1 and a second discharge hole H2 formed in a wall defining the second cylinder chamber CH2.

[0039] The first discharge hole H1 discharges gas generated in the cylinder chamber CH as a result of the hydraulic oil 10a being irradiated with radiation from inside the first cylinder chamber CH1 to outside the first cylinder chamber CH1, while the second discharge hole H2 discharges gas generated in the cylinder chamber CH as a result of the hydraulic oil 10a being irradiated with radiation from inside the second cylinder chamber CH2 to outside the second cylinder chamber CH2.

[0040] The reservoir tank 6 contains the oil 10b. More specifically, the reservoir tank 6 has a space SP that contains the oil 10b. The reservoir tank 6 has already been described, so a repeated description of the reservoir tank 6 will be omitted.

[0041] The pipe 5 fluidly connects the cylinder chamber CH and the reservoir tank 6. In the example shown in FIG. 1, the pipe 5 is filled with oil 10c. The oil 10c in the pipe 5 is oil having the same components as the hydraulic oil 10a in the cylinder chamber CH. In this specification, in order to formally distinguish between the oil 10c in the pipe 5 and the oil in the cylinder chamber CH (i.e., the oil that contributes to vibration damping), the former will be referred to as "oil 10c" and the latter will be referred to as "hydraulic oil 10a."

[0042] The pipe 5 has a first end 5a that is fluidly connected to the first cylinder chamber CH1. In the example shown in Fig. 1, the first end 5a and the first cylinder chamber CH1 are fluidly connected to each other via a first discharge hole H1.

[0043] The pipe 5 has a second end 5b that is fluidly connected to the second cylinder chamber CH2. In the example shown in Fig. 1, the second end 5b and the second cylinder chamber CH2 are fluidly connected via a second discharge hole H2.

[0044] The pipe 5 has a third end 5c that is fluidly connected to the reservoir tank 6 (more specifically, the space SP of the reservoir tank 6). In the example shown in Fig. 1, the third end 5c and the space SP of the reservoir tank 6 are fluidly connected via a communication hole 6h.

[0045] In the example shown in FIG. 1, the piping 5 includes a first pipe section 51 that connects the first cylinder chamber CH1 and the reservoir tank 6, and a second pipe section 52 that connects the second cylinder chamber CH2 and the reservoir tank 6. In the example shown in FIG. 1, a part of the first pipe section 51 and a part of the second pipe section 52 are common to each other. More specifically, the piping 5 has a junction section 5d where the first pipe section 51 and the second pipe section 52 join together, and a pipe section above the junction section 5d corresponds to a part where a part of the first pipe section 51 and a part of the second pipe section 52 are common to each other. Alternatively, the first pipe section 51 and the second pipe section 52 may be completely separated from each other.

[0046] A first check valve 7a and a second check valve 7b are disposed in the piping 5. More specifically, the first check valve 7a is disposed in the first pipe section 51, and the second check valve 7b is disposed in the second pipe section 52.

[0047] The first check valve 7a prevents the oil 10c in the first pipe portion 51 from flowing toward the reservoir tank 6, thereby suppressing the discharge of the hydraulic oil 10a from the first cylinder chamber CH1 through the first discharge hole H1 (more specifically, it substantially prevents the hydraulic oil 10a from being discharged from the first cylinder chamber CH1). In addition, when the first check valve 7a is in an open state, the gas generated in the cylinder chamber CH moves to the reservoir tank 6 through the first discharge hole H1 and the first check valve 7a.

[0048] The second check valve 7b prevents the oil 10c in the second pipe portion 52 from flowing toward the reservoir tank 6, thereby suppressing the discharge of the hydraulic oil 10a from the second cylinder chamber CH2 through the second discharge hole H2 (more specifically, it substantially prevents the hydraulic oil 10a from being discharged from the second cylinder chamber CH2). In addition, when the second check valve 7b is in an open state, the gas generated in the cylinder chamber CH moves to the reservoir tank 6 through the second discharge hole H2 and the second check valve 7b.

[0049] In the example shown in FIG. 2, when an earthquake force acts on the vibration-damping target device 13, the piston rod 12 and the piston 2 move relative to the cylinder main body 1a.

[0050] For example, as illustrated in FIG. 4, when the piston 2 moves in a direction toward the first cylinder chamber CH1, the first cylinder chamber CH1 is pressurized and the second cylinder chamber CH2 is depressurized. Thus, a part of the hydraulic oil 10a moves from the first cylinder chamber CH1 to the second cylinder chamber CH2. The movement of a part of the hydraulic oil 10a absorbs the seismic energy applied to the vibration-damping target equipment 13, and the vibration of the vibration-damping target equipment 13 is damped. When the piston 2 moves toward the first cylinder chamber CH1, the first check valve 7a arranged in the first pipe section 51 is closed, so that the hydraulic oil 10a does not move directly from the pressurized first cylinder chamber CH1 to the reservoir tank 6. Therefore, the damping function of the oil damper 100A in the reactor containment vessel is not impaired due to the presence of the first discharge hole H1.

[0051] When gas G is generated from the hydraulic oil 10a in the cylinder chamber CH due to irradiation with radiation (in other words, when gas G due to irradiation of the hydraulic oil 10a exists in the cylinder chamber CH), the gas G moves through the pipe 5 to the reservoir tank 6. Thus, the damping function of the oil damper 100A in the containment vessel is prevented or suppressed from being impaired due to irradiation of the hydraulic oil 10a. More specifically, when the piston 2 moves in a direction toward the first cylinder chamber CH1, the second cylinder chamber CH2 is depressurized and the second check valve 7b arranged in the second pipe section 52 is opened. Thus, the gas present in the cylinder chamber CH moves to the reservoir tank 6 through the second discharge hole H2 and the second check valve 7b. When the gas moves across the second check valve 7b, the oil 10c may move across the second check valve 7b in the opposite direction to the movement direction of the gas. When the gas moves to the reservoir tank 6, the second piston 8 in the reservoir tank 6 moves in a direction that pushes the spring 9. Thus, the volume of the space SP of the reservoir tank 6 that is connected to the pipe 5 is expanded according to the amount of gas flowing into the reservoir tank 6. When the cylinder 1 has the gas communication part 21, the gas G present in the first cylinder chamber CH1 can be moved to the reservoir tank 6 via the gas communication part 21, the second cylinder chamber CH2, the second discharge hole H2, and the second check valve 7b.

[0052] Next, an example in which the piston 2 moves in a direction toward the second cylinder chamber CH2 will be described. As illustrated in FIG. 5, when the piston 2 moves in a direction toward the second cylinder chamber CH2, the second cylinder chamber CH2 is pressurized and the first cylinder chamber CH1 is depressurized. Thus, a part of the hydraulic oil 10a moves from the second cylinder chamber CH2 to the first cylinder chamber CH1. The movement of a part of the hydraulic oil 10a absorbs the seismic energy imparted to the vibration-damping target device 13, and the vibration of the vibration-damping target device 13 is damped. When the piston 2 moves toward the second cylinder chamber CH2, the second check valve 7b disposed in the second pipe section 52 is closed, so that the hydraulic oil 10a does not move directly from the pressurized second cylinder chamber CH2 to the reservoir tank 6. Therefore, the damping function of the oil damper 100A in the reactor containment vessel is not impaired due to the presence of the second discharge hole H2.

[0053] When gas G is generated from the hydraulic oil 10a in the cylinder chamber CH due to irradiation with radiation (in other words, when gas G due to irradiation of the hydraulic oil 10a exists in the cylinder chamber CH), the gas G moves through the pipe 5 to the reservoir tank 6. Thus, the damping function of the oil damper 100A in the containment vessel is prevented or suppressed from being impaired due to irradiation of the hydraulic oil 10a. More specifically, when the piston 2 moves in a direction toward the second cylinder chamber CH2, the first cylinder chamber CH1 is depressurized and the first check valve 7a arranged in the first pipe section 51 is opened. Thus, the gas present in the cylinder chamber CH moves to the reservoir tank 6 through the first discharge hole H1 and the first check valve 7a. When the gas moves across the first check valve 7a, the oil 10c may move across the first check valve 7a in the opposite direction to the movement direction of the gas. When the gas moves to the reservoir tank 6, the second piston 8 in the reservoir tank 6 moves in a direction that pushes the spring 9. Thus, the volume of the space SP of the reservoir tank 6 that is connected to the pipe 5 is expanded according to the amount of gas flowing into the reservoir tank 6. When the cylinder 1 has the gas communication part 21, the gas G present in the second cylinder chamber CH2 can be moved to the reservoir tank 6 via the gas communication part 21, the first cylinder chamber CH1, the first discharge hole H1, and the first check valve 7a.

[0054] Second Embodiment An oil damper 100B in a containment vessel according to a second embodiment will be described with reference to Fig. 6. Fig. 6 is a schematic diagram showing the configuration of the oil damper 100B in a containment vessel according to the second embodiment.

[0055] In the second embodiment, differences from the first embodiment will be mainly described. On the other hand, in the second embodiment, repeated descriptions of matters already described in the first embodiment will be omitted. Therefore, it goes without saying that the matters already described in the first embodiment can be applied to the second embodiment even if they are not explicitly described in the second embodiment.

[0056] (composition) As illustrated in FIG. 6, an oil damper 100B for an inside of a containment vessel according to the second embodiment includes a cylinder body 1a and a piston 2. The cylinder body 1a and the piston 2 are arranged in a cylinder shape.

[0057] The cylinder body 1a defines a cylinder chamber CH that contains hydraulic oil 10a. The piston 2 is disposed within the cylinder chamber CH.

[0058] In the second embodiment, the hydraulic oil 10a is made of a radiation-resistant hydraulic oil so that substantial gas generation is prevented even when the hydraulic oil 10a is exposed to radiation. The radiation-resistant hydraulic oil is, for example, a polyphenyl ether-based hydraulic oil.

[0059] (action) The hydraulic oil 10a moves in the cylinder chamber CH in response to the relative movement of the piston 2 with respect to the cylinder body 1a. Thus, the vibration of the piston 2 with respect to the cylinder body 1a is damped. In addition, since the hydraulic oil 10a is a radiation-resistant hydraulic oil (e.g., a polyphenyl ether-based radiation-resistant hydraulic oil), even if the hydraulic oil 10a is exposed to radiation, only a very small amount of gas is generated from the hydraulic oil 10a (in other words, substantial generation of gas from the hydraulic oil 10a is prevented).

[0060] (effect) In the second embodiment, even if the hydraulic oil 10a is irradiated with radiation, only a very small amount of gas is generated from the hydraulic oil 10a (in other words, substantial generation of gas from the hydraulic oil 10a is prevented). Therefore, even if the hydraulic oil 10a is irradiated with radiation, the cylinder chamber CH can be kept filled with the hydraulic oil 10a. Therefore, the oil damper 100B in the reactor containment vessel in the second embodiment can exert a sufficient damping function in the reactor containment vessel under severe accident conditions, similar to under normal conditions.

[0061] Next, optional additional configurations that can be adopted in the second embodiment will be described with reference to FIG. 2 and FIG.

[0062] (Cylinder 1, vibration control target device 13, and support structure 14) As illustrated in Fig. 6, the oil damper 100B in the containment vessel includes a cylinder 1. The cylinder 1 includes a cylinder body 1a that defines a cylinder chamber CH, a piston 2 that is disposed in the cylinder chamber CH, and a piston rod 12 that is connected to the piston 2. In the example illustrated in Fig. 6, the cylinder body 1a includes a first connection portion 11a (more specifically, a cylinder cover ear), and the piston rod 12 includes a second connection portion 12a.

[0063] 6, the cylinder 1 has a first cylinder chamber CH1 arranged on one side of the piston 2, a second cylinder chamber CH2 arranged on the other side of the piston 2, and a communication part 23 that allows the hydraulic oil 10a to move between the first cylinder chamber CH1 and the second cylinder chamber CH2. The cylinder 1 may have a piston ring 3 attached to the outer circumferential surface of the piston 2. The first cylinder chamber CH1, the second cylinder chamber CH2, the communication part 23, and the piston ring 3 have been described in the first embodiment, so repeated description of the first cylinder chamber CH1, the second cylinder chamber CH2, the communication part 23, and the piston ring 3 will be omitted.

[0064] In the example shown in FIG. 2, the cylinder body 1a (more specifically, the first connection part 11a) is connected to the vibration-damping target equipment 13 in the reactor containment vessel, and the piston rod 12 (more specifically, the second connection part 12a) is connected to the support structure 14. In this way, the vibration-damping target equipment 13 is connected to the support structure 14 via the oil damper 100 in the reactor containment vessel. Alternatively, the cylinder body 1a (more specifically, the first connection part 11a) may be connected to the support structure 14, and the piston rod 12 (more specifically, the second connection part 12a) may be connected to the vibration-damping target equipment 13 in the reactor containment vessel.

[0065] When an earthquake force acts on the vibration-damping target device 13, the piston 2 moves relative to the cylinder body 1a. In the example shown in FIG. 6, when the piston 2 moves relative to the cylinder body 1a, one of the first cylinder chamber CH1 and the second cylinder chamber CH2 (more specifically, the chamber on the moving direction side of the piston 2) is pressurized, and the other of the first cylinder chamber CH1 and the second cylinder chamber CH2 (more specifically, the chamber on the opposite side to the moving direction of the piston 2) is depressurized. Thus, a part of the hydraulic oil 10a moves from one chamber to the other chamber. The movement of a part of the hydraulic oil 10a absorbs the earthquake energy applied to the vibration-damping target device 13, and the vibration of the vibration-damping target device 13 is damped. In the second embodiment, even if the hydraulic oil 10a is irradiated with radiation, only a very small amount of gas is generated from the hydraulic oil 10a, so that the vibration of the vibration-damping target device 13 is effectively damped even under severe accident conditions.

[0066] (Third embodiment) An oil damper 100C in a containment vessel according to a third embodiment will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing the configuration of the oil damper 100C in a containment vessel according to the third embodiment.

[0067] The oil damper 100C in the containment vessel of the third embodiment differs from the oil damper 100A in the containment vessel of the first embodiment in that the hydraulic oil 10a is the radiation-resistant hydraulic oil (e.g., polyphenyl ether-based radiation-resistant hydraulic oil) described in the second embodiment and the reservoir tank 6 is miniaturized. In other respects, the third embodiment is similar to the first embodiment.

[0068] In the third embodiment, differences from the first and second embodiments will be mainly described. On the other hand, in the third embodiment, repeated descriptions of matters already described in the first or second embodiment will be omitted. Therefore, it goes without saying that the matters already described in the first or second embodiment can be applied to the third embodiment even if they are not explicitly described in the third embodiment.

[0069] (composition) As illustrated in FIG. 7, an oil damper 100C in a containment vessel according to the third embodiment includes a cylinder body 1a, a piston 2, and a reservoir tank 6 (more specifically, a small reservoir tank).

[0070] The cylinder body 1a defines a cylinder chamber CH that contains hydraulic oil 10a. The piston 2 is disposed within the cylinder chamber CH. The reservoir tank 6 is fluidly connected to the cylinder chamber CH and receives gas generated within the cylinder chamber CH.

[0071] The oil damper 100C in the reactor containment vessel is configured so that gas generated in the cylinder chamber CH when the hydraulic oil 10a is exposed to radiation moves from the cylinder chamber CH to the reservoir tank 6. Moreover, the hydraulic oil 10a is made of radiation-resistant hydraulic oil so that substantial generation of gas is prevented even when the hydraulic oil 10a is exposed to radiation (in other words, so that the amount of gas generated from the hydraulic oil 10a is kept to an extremely small amount).

[0072] (action) The hydraulic oil 10a moves in the cylinder chamber CH in response to the relative movement of the piston 2 with respect to the cylinder body 1a. In this way, the vibration of the piston 2 with respect to the cylinder body 1a is damped. In addition, when the hydraulic oil 10a is exposed to radiation, a very small amount of gas is generated from the hydraulic oil 10a in the cylinder chamber CH. The gas generated in the cylinder chamber CH moves to the reservoir tank 6 via the exhaust hole H and the piping 5 formed in the wall that defines the cylinder chamber CH, and the gas is received in the reservoir tank 6.

[0073] (effect) In the third embodiment, the hydraulic oil 10a is configured such that gas generated in the cylinder chamber CH when the hydraulic oil 10a is exposed to radiation moves to the reservoir tank 6. Therefore, gas generated from the hydraulic oil 10a due to radiation irradiation does not remain in the cylinder chamber CH, and the cylinder chamber CH can be kept filled with the hydraulic oil 10a. Therefore, the oil damper 100C in the containment vessel in the third embodiment can exhibit a sufficient damping function in the containment vessel under severe accident conditions, similar to under normal conditions.

[0074] In the third embodiment, the hydraulic oil 10a is made of radiation-resistant hydraulic oil. Therefore, the amount of gas generated from the hydraulic oil 10a by radiation exposure is very small, so the size of the reservoir tank 6 that receives the gas can be reduced, and the overall size of the oil damper 100C in the containment vessel can be reduced. Thus, in the third embodiment, it is possible to provide the oil damper 100C in the containment vessel that can be arranged in a narrow space in the containment vessel.

[0075] The third embodiment is similar to the first embodiment, except that the hydraulic oil 10a is a radiation-resistant hydraulic oil, and it is possible to reduce the size of the reservoir tank 6. Therefore, each of the optional configurations described in the first embodiment can also be adopted in the third embodiment.

[0076] (Fourth embodiment) A vibration damping system 200 in a fourth embodiment will be described with reference to Fig. 8. Fig. 8 is a schematic side view showing an example of a connection relationship between the oil damper 100 in the containment vessel, the vibration damping target equipment 13, and the displacement amplification mechanism 15 in the embodiment.

[0077] In the fourth embodiment, differences from the first, second and third embodiments will be mainly described. On the other hand, in the fourth embodiment, repeated descriptions of matters already described in the first, second or third embodiments will be omitted. Therefore, it goes without saying that the matters already described in the first, second or third embodiments can be applied to the fourth embodiment even if they are not explicitly described in the fourth embodiment.

[0078] (composition) As illustrated in FIG. 8, a vibration control system 200 according to the fourth embodiment includes an oil damper 100 in a containment vessel and a displacement amplification mechanism 15. The oil damper 100 is disposed in the containment vessel.

[0079] 8, the oil damper 100 in the containment vessel may be the oil damper 100A in the containment vessel in the first embodiment, the oil damper 100B in the containment vessel in the second embodiment, or the oil damper 100C in the containment vessel in the third embodiment. The oil damper 100 in the containment vessel has been described in the first to third embodiments, so a repeated description of the oil damper 100 in the containment vessel will be omitted.

[0080] 8(a) and 8(b), the displacement amplification mechanism 15 amplifies the displacement of the vibration-control target equipment 13, which is damped by the oil damper 100 inside the containment vessel, in response to an earthquake input. In addition, the displacement amplification mechanism 15 amplifies the displacement of the vibration-control target equipment 13, thereby suppressing a decrease in the damping effect caused by the gas present in the cylinder chamber CH.

[0081] In the example shown in FIG. 8, the displacement amplification mechanism 15 includes a spring 16, an actuator 17, and a vibration receiving portion .

[0082] The vibration receiving portion 18 is disposed in contact with the vibration-damping target device 13. The vibration receiving portion 18 transmits the displacement of the vibration-damping target device 13 to the spring 16 and the actuator 17. The vibration receiving portion 18 may have a displacement direction conversion portion 18c (e.g., an inclined surface for displacement direction conversion) that converts the displacement of the vibration-damping target device 13 in a direction parallel to the first direction DR1 into the displacement of the vibration receiving portion 18 in a direction parallel to a second direction DR2 different from the first direction DR1. The second direction DR2 is, for example, a direction perpendicular to the first direction DR1.

[0083] The actuator 17 has an actuator body 17a and a rod 17b. In the example shown in Fig. 8, the actuator 17 is a passive actuator that expands and contracts due to the force received from the vibration receiving portion 18 and the spring 16. The actuator 17 may be attached to the support structure 14 or to another structure.

[0084] 8, when the rod 17b of the actuator 17 receives a force from the vibration receiver 18 in the second direction DR2, the tip of the rod 17b moves in a direction toward the actuator main body 17a. In this way, the actuator 17 contracts. When the rod 17b of the actuator 17 receives a force from the vibration receiver 18 in a third direction DR3 opposite to the second direction DR2, the tip of the rod 17b moves in a direction away from the actuator main body 17a. In this way, the actuator 17 expands.

[0085] 8, the spring 16 contracts in response to the displacement of the vibration receiving portion 18 in the second direction DR2. The contracted spring 16 presses the vibration receiving portion 18 in the third direction DR3 due to the force of the spring 16 returning to its original shape.

[0086] (action) When an earthquake force acts on the vibration-damping target equipment 13, the vibration-damping target equipment 13 displaces the vibration receiving part 18 in the direction in which the spring 16 of the displacement amplification mechanism 15 contracts. Also, due to the restoring force of the spring 16, the vibration receiving part 18 and the vibration-damping target equipment 13 are each displaced in the direction opposite to that when the spring 16 contracts. In this way, the displacement amplification mechanism 15 amplifies the displacement and vibration of the vibration-damping target equipment 13 in response to the earthquake input, compared to when the vibration-damping target equipment 13 is rigidly connected to a structure (e.g., the support structure 14).

[0087] (effect) Since the displacement and vibration of the vibration-control target equipment 13 are amplified by the displacement amplifying mechanism 15, even if a trace amount of gas remains in the cylinder 1 of the oil damper 100 inside the containment vessel, it is possible to suppress a decrease in the damping effect of the oil damper 100 inside the containment vessel caused by the presence of the gas. Therefore, the vibration control system 200 in the fourth embodiment can exert a sufficient damping function inside the containment vessel under severe accident conditions, similar to under normal conditions.

[0088] When the displacement amplification mechanism 15 includes the displacement direction converter 18c, the actuator 17 can be disposed in a narrow space inside the reactor containment vessel.

[0089] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0090] 1...cylinder, 1a...cylinder body, 2...piston, 3...piston ring, 3h...opening, 5...piping, 5a...first end of piping, 5b...second end of piping, 5c...third end of piping, 5d...junction of piping, 6...reservoir tank, 6a...tank body, 6h...communication hole, 7...check valve, 7a...first check valve, 7b...second check valve, 8...second piston, 9...spring, 10a...hydraulic oil, 10b, 10c...oil, 11a...first connection part, 12...piston rod, 12a...second connection part, 13...device to be damped, 14...support structure, 15...displacement amplification mechanism, 16... , 17... actuator, 17a... actuator main body, 17b... rod, 18... vibration receiving portion, 18c... displacement direction conversion portion, 21... gas communication portion, 23... communication portion, 23h... through hole portion, 51... first pipe portion, 52... second pipe portion, 100, 100A, 100B, 100C... oil damper in reactor containment vessel, 200... vibration control system, CH... cylinder chamber, CH1... first cylinder chamber, CH2... second cylinder chamber, DR1... first direction, DR2... second direction, DR3... third direction, G... gas, H... exhaust hole, H1... first exhaust hole, H2... second exhaust hole, SP... space

Claims

1. a cylinder body defining a cylinder chamber for accommodating hydraulic oil; A piston disposed in the cylinder chamber; a reservoir tank fluidly connected to the cylinder chamber and configured to receive gas generated within the cylinder chamber; a check valve that prevents the hydraulic oil from moving from the cylinder chamber toward the reservoir tank; Equipped with The hydraulic oil is exposed to radiation, and gas generated in the cylinder chamber is discharged to the outside of the cylinder chamber. the check valve is disposed at a position higher than the cylinder chamber and lower than the reservoir tank, When the check valve is in an open state, gas generated in the cylinder chamber moves to the reservoir tank via the check valve. Oil damper inside the reactor containment vessel.

2. A cylinder body defining a cylinder chamber for accommodating hydraulic oil; A piston disposed in the cylinder chamber; Equipped with The hydraulic oil is made of a polyphenyl ether-based radiation-resistant hydraulic oil so that substantial gas generation is prevented even when the hydraulic oil is exposed to radiation. Oil damper inside the reactor containment vessel.

3. The cylinder chamber is a first cylinder chamber disposed on one side of the piston; a second cylinder chamber disposed on the other side of the piston; a gas communication portion disposed at an upper end of the cylinder chamber and allowing gas generated in the cylinder chamber to move between the first cylinder chamber and the second cylinder chamber; have The oil damper in a nuclear reactor containment vessel according to claim 1.

4. a cylinder having the cylinder body and the piston; a pipe fluidly connecting the cylinder chamber and the reservoir tank; Equipped with The cylinder is a first cylinder chamber disposed on one side of the piston; a second cylinder chamber disposed on the other side of the piston; a communication portion that allows the hydraulic oil to move between the first cylinder chamber and the second cylinder chamber; A first discharge hole formed in a wall defining the first cylinder chamber; a second discharge hole formed in a wall defining the second cylinder chamber; having The piping includes: a first check valve that prevents the hydraulic oil from being discharged from the first cylinder chamber through the first discharge hole; a second check valve that prevents the hydraulic oil from being discharged from the second cylinder chamber through the second discharge hole; is placed, When the first check valve is in an open state, gas generated in the cylinder chamber moves to the reservoir tank via the first check valve, When the second check valve is in an open state, gas generated in the cylinder chamber moves to the reservoir tank via the second check valve. The oil damper in a nuclear reactor containment vessel according to claim 1.

5. a reservoir tank fluidly connected to the cylinder chamber for receiving gas generated within the cylinder chamber; The hydraulic oil is configured so that gas generated in the cylinder chamber when the hydraulic oil is exposed to radiation moves from the cylinder chamber to the reservoir tank; and The hydraulic oil is made of the polyphenyl ether-based radiation-resistant hydraulic oil so that the amount of gas generated from the hydraulic oil is very small even when the hydraulic oil is exposed to radiation. The oil damper in a nuclear reactor containment vessel according to claim 2.

6. The oil damper in a nuclear reactor containment vessel according to any one of claims 1 to 5, a displacement amplification mechanism that amplifies the displacement of the vibration-damping target equipment that is damped by the oil damper in the reactor containment vessel; Equipped with The displacement amplifying mechanism amplifies the displacement of the vibration-damping target device, thereby suppressing a decrease in the damping effect caused by the gas present in the cylinder chamber. Vibration control system.

Images