JP2006153869A - Boiling water reactor and its acoustic vibration suppression method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress pressure vibration accompanying acoustic resonance occurring in a main steam system of a boiling water reactor. <P>SOLUTION: Pressure sensors 13 and 14 are disposed in a steam dome 6 and a steam pipe 9, and pressure vibration amplitude is detected. The steam dome 6 or steam pipe 9 is provided with a Helmholtz resonance tube 12, and an opening regulating valve 11 is mounted to an inlet pipe 121. The opening of the opening regulating valve 11 is regulated in the direction of decreasing the detected pressure vibration amplitude. Thus, when the detected pressure vibration amplitude becomes minimum, the resonance frequency of the Helmholtz resonance tube 12 matches with (is close to) resonance vibration frequency of the steam system, and can effectively suppress the pressure vibration due to the acoustic resonance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a boiling water reactor, and more particularly to a boiling water reactor suitable for suppressing pressure oscillations in a steam system.

  It has been reported that when the power generation capacity of a boiling water reactor is increased, the pressure oscillation increases as the main steam flow rate increases, leading to equipment damage. In order to avoid damage to equipment, measures such as optimizing the flow path shape of the main steam system and increasing the structural strength are taken, and such cases and measures are disclosed in Non-Patent Document 1.

  Further, for example, Non-Patent Document 2 and the like disclose a technique that uses a Helmholtz resonance tube in the field of thermal power generation in order to attenuate acoustic vibration of a gas turbine combustion chamber.

NRC SPECIAL INSPECTION REPORT 50-265 / 03-11 Journal of Engineering for Gas Turbines and Power April 2004, Vol.126 P.271-275

  One of the causes of pressure oscillations in the main steam system in a boiling water reactor is considered to be acoustic resonance. In the main steam system from the steam dome of the reactor pressure vessel to the high-pressure turbine through the main steam pipe, a pressure wave is generated due to fluid fluctuations, and propagates and reflects in the system. As a result, a standing wave (acoustic resonance mode) having a large amplitude is formed, and the amplitude of the pressure vibration may be amplified. In particular, in a plant having an increased power generation capacity, fluid resonance increases as the main steam flow rate increases, so that acoustic resonance may occur. Since such an acoustic resonance phenomenon is affected by the piping configuration and boundary conditions of the plant, the vibration characteristics vary from plant to plant. For this reason, it is difficult to predict the frequency, amplitude, position of the maximum amplitude, etc. in advance, and it is necessary to design the equipment with a sufficiently large safety margin in order to ensure the soundness of the equipment. There is.

  An object of the present invention is to suppress pressure vibration accompanying acoustic resonance generated in the main steam system of a boiling water reactor.

  In one aspect of the present invention, a Helmholtz resonance pipe is installed in a steam system including a steam phase portion of a reactor pressure vessel and steam piping.

  Here, in a preferred embodiment of the present invention, the pressure vibration of the steam system composed of the steam phase part of the reactor pressure vessel and the steam pipe is detected, and the resonance frequency of the Helmholtz resonance tube is set in a direction to reduce the pressure vibration. adjust. In order to realize this adjustment, it is desirable to provide an adjustment valve that adjusts the cross-sectional area of the inlet pipe of the Helmholtz resonance pipe.

  In another aspect of the present invention, an opening adjustment valve is arranged in a connection pipe that connects the main flow paths of the steam system and / or a branch pipe that branches from the main flow path, and the opening of the opening adjustment valve is adjusted. It is characterized by.

  Here, in a desirable embodiment of the present invention, the pressure vibration of the steam system composed of the steam phase portion of the reactor pressure vessel and the steam pipe is detected, and the opening degree of the opening adjustment valve is reduced in a direction to reduce the pressure vibration. Adjust. In order to realize this adjustment, a plurality of opening adjustment valves are provided for a plurality of connection pipes and / or branch pipes provided in a main steam system pipe between the reactor pressure vessel and the high-pressure turbine, and the detected pressure It is desirable to provide a control means for decreasing the pressure oscillation amplitude of the steam system by sequentially adjusting the openings of the plurality of opening adjustment valves in the direction of reducing the vibration.

  ADVANTAGE OF THE INVENTION According to this invention, the pressure vibration accompanying the acoustic resonance which generate | occur | produces in the main steam system of a boiling water reactor can be suppressed. Even when pressure vibrations are generated, if a control means for suppressing pressure vibrations is provided, the plant can be maintained in an optimum state.

  Other objects and features of the present invention will become apparent from the following description of the embodiments.

  Hereinafter, a boiling water reactor according to an embodiment of the present invention will be described with reference to the drawings.

Example 1:
FIG. 1 is a configuration diagram of a steam system of a boiling water reactor according to Embodiment 1 of the present invention. The steam 2 generated inside the reactor pressure vessel 1 is removed by the corrugated plate 4 inside the steam dryer 3 and then flows into the steam dome 6 surrounded by the lid 5 of the reactor pressure vessel 1. To do. The removed moisture passes through the drain pipe 7 and is discharged below the steam dryer 3. Thereafter, the steam 2 flows from the nozzle 8 through the steam pipe 9 into the high-pressure turbine 10.

  A Helmholtz resonance tube 12 is installed in the steam dome 6 through an opening adjustment valve 11. That is, the Helmholtz resonance tube 12 is installed in the steam dome 6 by communicating the opening of the steam dome 6 such as a spare valve seat and the inlet pipe 121 (FIG. 2) of the Helmholtz resonance tube 12. On the other hand, pressure sensors 13 and 14 are attached to a steam phase space (hereinafter referred to as a steam system) from the steam dome 6 through the nozzle 8 and the steam pipe 9 to the high pressure turbine 10. Here, either one of the pressure sensors 13 and 14 or a plurality of the pressure sensors 13 and 14 may be installed. The pressure vibration signals from the pressure sensors 13 and 14 are processed by a signal processing unit in the control device 15, and the control device 15 controls the opening degree of the opening adjustment valve 11. In particular, this embodiment is effective when the pressure oscillation of the steam dome 6 is large.

  FIG. 2 is a side view showing the structure of a cylindrical Helmholtz resonance tube 12 suitable for use in this embodiment. The Helmholtz resonance pipe 12 includes two components, a cylindrical inlet pipe 121 and a cylindrical resonance attenuation pipe 122, and the shapes of the inlet pipe 121 and the resonance attenuation pipe 122 are not necessarily limited to a cylindrical shape. There is no. The resonance frequency f of the Helmholtz resonance tube 12 can be expressed by equation (1).

f = c / (2π) × (An / (VLn)) ^0.5 (1)
Here, f is the resonance frequency (Hz), c is the speed of sound (m / s), An is the cross-sectional area (m ² ) of the inlet pipe 121, V is the volume (m ³ ) of the resonance damping pipe 122, and Ln is the inlet pipe. 121 length (m).

  As shown in FIG. 2, the opening adjustment valve 11 shown in FIG. 1 is attached to the inlet pipe 121 of the Helmholtz resonance pipe 12. It is possible to adjust the cross-sectional area An of the inlet pipe 121 by adjusting the opening degree of the opening adjusting valve 11, and it is understood from the equation (1) that the resonance frequency f of the Helmholtz resonance pipe 12 can be adjusted. .

  FIG. 3 shows an example in which the resonance frequency of the cylindrical Helmholtz resonance tube 12 is obtained. The resonance frequency f varies depending on the diameter Dn of the inlet pipe 121, its length Ln, the diameter Dr of the resonance damping pipe 122, its length Lr, and the like. In particular, the resonance frequency f changes due to a change in the diameter Dn of the inlet pipe 121. Therefore, by changing the opening degree of the opening adjustment valve 11 provided in the inlet pipe 121, the diameter Dn of the inlet pipe 121 can be changed equivalently, and the resonance frequency f of the Helmholtz resonance pipe 12 can be changed. Since the acoustic resonance mode sound wave length is usually longer than the pipe diameter, the resonance frequency f depends on the opening area regardless of the shape of the opening. For this reason, the resonance frequency f of the Helmholtz resonance tube 12 can be adjusted regardless of the type of the opening adjustment valve.

  The illustrated example shows three resonance frequency characteristics with respect to the length Lr of the resonance attenuating tube 122 using the diameter Dn of the inlet pipe 121 as a parameter, and the resonance frequency f is lowered by reducing the diameter Dn. That is, in one Helmholtz resonance pipe 12, if the opening degree of the opening degree adjustment valve 11 is changed, the diameter Dn of the inlet pipe 121 can be changed equivalently, and the resonance frequency f can be adjusted. Yes.

  1, when an acoustic resonance mode having a resonance frequency f is formed in the steam system from the steam dome 6 through the nozzle 8 and the steam pipe 9 to the high-pressure turbine 10, the Helmholtz resonance pipe 12 By making the resonance frequency f equal to the frequency of the acoustic resonance mode, the amplitude of the acoustic resonance mode of the vapor system can be attenuated.

  When the pressure wave propagates, reflects and amplifies in the vapor system, an acoustic resonance mode having a large amplitude is formed. When the pressure at the inlet of the Helmholtz resonance tube 12 fluctuates in this acoustic resonance mode, a flow velocity variation toward the inside of the Helmholtz resonance tube 12 occurs. When the resonance frequency f of the Helmholtz resonance tube 12 coincides with the frequency of the acoustic resonance mode, the flow velocity fluctuation at the inlet of the Helmholtz resonance tube 12 increases, so that the Helmholtz resonance tube 12 absorbs the acoustic energy in the vapor system and effectively The acoustic resonance mode can be attenuated. Therefore, the acoustic resonance mode can be effectively attenuated by providing the inlet of the Helmholtz resonance tube 12 at a position where the pressure oscillation is large in the vapor system. For example, when a large pressure vibration is generated in the steam dryer 3, the Helmholtz resonance tube is installed in the vicinity of the steam dryer 3 of the steam dome 6 to suppress the pressure vibration and the fluctuation applied to the steam dryer 3. By reducing the force, the reliability can be further increased.

  The control device 15 receives pressure vibration signals from the pressure sensors 13 and 14 and optimally controls the opening degree of the opening degree adjusting valve 11 so that the pressure vibration amplitude of the pressure sensors 13 and 14 is minimized. For example, when the opening degree adjusting valve 11 is slightly opened, if the pressure vibration amplitude of the pressure sensors 13 and 14 is reduced, the opening degree adjusting valve is further opened minutely. Moreover, when the pressure vibration amplitude of the pressure sensors 13 and 14 increases, the opening degree adjusting valve 11 is controlled to close in the opposite direction. By repeating this operation, the opening degree of the opening adjustment valve 11 can be controlled to minimize the pressure vibration amplitude of the pressure sensors 13 and 14.

  FIG. 4 is a processing function block diagram of the control device 15 suitable for use in this embodiment. The control device 15 includes a signal processing unit 151 and a control unit 152. In the signal processing unit 151, the pressure vibration amplitude input from the pressure sensors 13 and 14 is stored in the storage unit 1511, and the pressure vibration amplitudes of the pressure sensors 13 and 14 before and after the operation of the opening adjustment valve 11 are compared in the comparison unit 1512. . Further, the control unit 152 determines a new opening command to the opening adjustment valve 11 from the comparison result of the comparison unit 1512, and outputs a control signal to the opening adjustment valve 11.

  With this functional configuration, the substantial opening area of the inlet pipe 121 of the Helmholtz resonance pipe 12 is adjusted in the direction in which the pressure vibration amplitude of the steam system becomes smaller, and the resonance frequency f of the Helmholtz resonance pipe 12 is the resonance vibration generated in the steam system. This can be attenuated by approaching the frequency.

Example 2:
FIG. 5 is a configuration diagram of a steam system of a boiling water reactor according to Embodiment 2 of the present invention. The steam 2 generated inside the reactor pressure vessel 1 is removed by the corrugated plate 4 inside the steam dryer 3 and then flows into the steam dome 6 surrounded by the lid 5 of the reactor pressure vessel 1. To do. The removed moisture passes through the drain pipe 7 and is discharged below the steam dryer 3. Thereafter, the steam 2 flows from the nozzle 8 through the steam pipe 9 into the high-pressure turbine 10. A Helmholtz resonance pipe 12 is installed in the steam pipe 9 via an opening degree adjusting valve 11. Pressure sensors 13 and 14 are attached to a vapor phase space (steam system) from the steam dome 6 through the nozzle 8 and the steam pipe 9 to the high pressure turbine 10. Here, either one of the pressure sensors 13 or 14 or a plurality of pressure sensors may be installed. The pressure vibration signals from the pressure sensors 13 and 14 are processed by a signal processing unit in the control device 15 and used for controlling the opening of the opening adjusting valve 11. The configurations of the Helmholtz resonance tube 12 and the control device 15 are the same as those in the first embodiment, and redundant description is avoided.

  In this embodiment, the Helmholtz resonance pipe 12 is installed in the steam pipe 9, and in this case as well, an acoustic resonance mode is provided by providing the inlet pipe 121 of the Helmholtz resonance pipe 12 at a position where the pressure vibration is large in the steam system. Can be effectively attenuated. This embodiment is effective when the pressure vibration of the steam pipe 9 is large. For example, when a large pressure vibration occurs in the nozzle 8, the Helmholtz resonance pipe 12 is installed in the vicinity of the nozzle 8 to suppress the pressure vibration of the steam pipe 9, thereby suppressing the pressure vibration of the entire steam system. can do. In the case of a boiling water reactor, since a safety valve is installed in the vicinity of the nozzle 8, when applied at the time of increased output, a large large-capacity safety valve with a large flow area is used to increase the output. It is possible to reduce the number of valves compared to the above, and to install a Helmholtz resonance tube using the remaining valve seat.

Example 3:
FIG. 6 is a configuration diagram of a steam system of a boiling water reactor according to the third embodiment of the present invention. The steam 2 generated inside the reactor pressure vessel 1 is removed by the corrugated plate 4 inside the steam dryer 3 and then flows into the steam dome 6 surrounded by the lid 5 of the reactor pressure vessel 1. To do. The removed moisture passes through the drain pipe 7 and is discharged below the steam dryer 3. Thereafter, the steam 2 flows from the nozzle 8 through the steam pipe 9 into the high-pressure turbine 10. The steam pipe 9 is provided with a Helmholtz resonance pipe 12A via an opening adjustment valve 11A, and a Helmholtz resonance pipe 12B via an opening adjustment valve 11B. Pressure sensors 13, 14 </ b> A, and 14 </ b> B are attached to a steam phase space (steam system) from the steam dome 6 to the high-pressure turbine 10 through the nozzle 8 and the steam pipe 9. Here, any one of the pressure sensors 13, 14A, 14B, or two of the three, or a plurality of each may be installed. The pressure vibration signals from these pressure sensors are processed by the control device 15 and used to control the opening of the opening adjusting valves 11A and 11B. The configurations of the Helmholtz resonance tubes 12A and 12B are the same as those in the first and second embodiments.

  In this embodiment, a steam header 16 is installed in the steam pipe 9. The steam header 16 is provided with a distributor-like role that makes it possible to equalize the pressure of each pipe of the steam pipe 9 constituted by a plurality of parallel pipes or to branch to another pipe. Thus, when the steam header 16 is installed, the phase of the acoustic resonance mode may be different before and after the steam header 16. Therefore, by providing Helmholtz resonance tubes 12A and 12B in the steam pipes 9 before and after the steam header 16, the acoustic resonance mode can be effectively attenuated. For example, when a large pressure vibration occurs in the steam header 16, the Helmholtz resonance pipes 12 </ b> A and 12 </ b> B are installed before and after the steam header 16 to suppress the pressure vibration of the steam pipe 9, and the pressure vibration of the entire steam system. Can be suppressed.

  The control device 15 inputs pressure vibration signals of the pressure sensors 13, 14A, and 14B, and optimally controls the opening degrees of the opening degree adjusting valves 11A and 11B so that the pressure vibration amplitudes are minimized. For example, when the valve 11A is slightly opened to decrease the pressure vibration amplitude of the pressure sensors 13, 14A, 14B, the opening degree adjusting valve 11A is further opened. Further, when the pressure vibration amplitude of the pressure sensors 13, 14A, 14B increases, the opening adjustment valve 11A is controlled to be closed in the opposite direction. By repeating this operation for the opening adjustment valves 11A and 11B, the opening degree of the opening adjustment valves 11A and 11B can be controlled to minimize the pressure vibration amplitude of the pressure sensors 13, 14A and 14B.

  The specific configuration of the control device 15 is the same as in FIG. The pressure vibration amplitudes from the pressure sensors 13, 14A, 14B are stored in the storage unit 1511, and the pressure vibration amplitudes of the pressure sensors 13, 14A, 14B before and after operating the opening adjustment valves 11A, 11B are compared by the comparison unit 1512, respectively. Then, from the comparison result, a new opening degree of the opening degree adjusting valves 11A, 11B may be determined, and a control unit 152 for controlling the opening degree adjusting valves 11A, 11B may be provided.

  If the inlet piping 121 of the Helmholtz resonance pipes 12A and 12B is at a position where the pressure oscillation is large in the steam system, the acoustic resonance mode can be attenuated more effectively. Therefore, if the pressure vibration signals from the pressure sensors 13, 14A and 14B are used in the control device 15 as means for determining the opening degree of the opening adjustment valves 11A and 11B, the sound can be more effectively sounded as follows. Resonance can be attenuated. That is, the acoustic vibration mode generated in the steam system is calculated, and the opening adjustment valve 11A or 11B corresponding to the Helmholtz resonance tube 12A or 12B provided at a position where the calculation result of the pressure vibration amplitude is large is newly added in order. The opening is determined and controlled from the opening adjustment valve. The acoustic vibration mode is obtained by numerical calculation using an appropriate boundary condition based on a compressible fluid equation or a sound wave equation, and a pressure vibration amplitude at each position in the steam system can be obtained. From this acoustic vibration mode, the pressure vibration amplitude at the position of the opening degree adjusting valves 11A and 11B is obtained, and the opening degree adjusting valve having the larger pressure vibration is preferentially controlled. By using this method, the optimum opening degree of the opening adjustment valves 11A and 11B can be obtained in a shorter time, and the pressure vibration can be attenuated.

Example 4:
FIG. 7 is a configuration diagram of a steam system of a boiling water reactor according to Embodiment 4 of the present invention. The steam 2 generated inside the reactor pressure vessel 1 goes to the steam header 16 through four parallel steam pipes 91 to 94. After passing through the steam header 16, it flows into the high-pressure turbine 10. Opening adjustment valves 171 to 174 are attached to the steam header 16 in pipes connecting the steam pipes 91 to 94. Here, the upper and lower semicircular portions of the steam header 16 shown in the figure are connected to each other, and therefore the opening degree adjusting valve 174 is provided in a pipe connecting the steam pipes 94 and 91. . Further, a pipe 18 for connecting the steam pipes 91 to 94 is provided between the steam header 16 and the high-pressure turbine 10, and the opening degree adjusting valves 191 to 193 are provided between the steam pipes 91 to 94 of the pipe 18. Is attached. A pressure sensor 13 is attached to the steam dome 6 of the reactor pressure vessel 1, and pressure sensors 141 to 144 are attached to steam pipes 91 to 94 from the reactor pressure vessel 1 to the steam header 16. Further, pressure sensors 145 to 148 are attached to steam pipes 91 to 94 from the steam header 16 to the high-pressure turbine 10. Here, it is not necessary to install all of the pressure sensors 13, 141 to 144, and 145 to 148, and a plurality of each may be installed. The pressure vibration signals from the pressure sensors 13, 141 to 144, and 145 to 148 are processed by the control device 15 and used to control the opening degree of the opening degree adjusting valves 171 to 174 and 191 to 193.

  In the present embodiment, opening adjustment valves 171 to 174 and 191 to 193 are provided in pipes connecting the steam pipes 91 to 94, and the steam dome 6, the steam pipes 91 to 94, the steam header 16 to the high pressure turbine 10 are provided. The opening adjustment valves 171 to 174 and 191 to 193 are controlled so as to suppress the acoustic resonance mode generated in the steam system (steam system). In a steam system having a plurality of parallel pipes and a connecting part that connects the parallel pipes, an acoustic resonance mode in which the parallel pipes are coupled may be formed. In the case of a present Example, three points, the steam dome 6, the steam header 16, and the piping 18, are the connection parts which connect parallel steam piping 91-94. In order to suppress the acoustic resonance mode in which the parallel pipes are coupled, it is effective to change the acoustic impedance of the connecting portion that connects the parallel pipes. For this reason, it becomes possible to change the acoustic impedance of the connection part which connects parallel piping by changing the opening degree of the opening degree adjustment valves 171 to 174 and 191 to 193, and to suppress the acoustic resonance mode. It becomes possible. The opening adjustment valves 171 to 174 and 191 to 193 do not have to be installed all, and a plurality of opening adjustment valves may be installed. This embodiment is effective in suppressing the acoustic resonance mode in which parallel pipes are coupled.

  The control device 15 inputs pressure vibration signals from the pressure sensors 13 and 141 to 148, and optimally controls the opening degrees of the opening degree adjusting valves 171 to 174 and 191 to 193 so that the pressure vibration amplitudes thereof are minimized. To do. In order to attenuate the acoustic resonance, first, the opening degree of the opening degree adjusting valves 171 to 174 and 191 to 193 is changed, and the sensitivity of the pressure sensors 13 and 141 to 148 with respect to the pressure vibration amplitude is obtained. For example, when the opening degree adjusting valve 171 is slightly opened and the pressure vibration amplitudes of the pressure sensors 13 and 141 to 148 are reduced, the opening degree adjusting valve 171 is further opened minutely. Moreover, when the pressure vibration amplitude of the pressure sensors 13 and 141 to 148 increases, the opening adjustment valve 171 is controlled to be closed in the opposite direction. For the opening adjustment valves 171 to 174 and 191 to 193, the operation of the opening adjustment valves 171 to 174 and 191 to 193 is controlled by repeating this operation in order from the opening adjustment valve having the highest sensitivity, so that the pressure vibration Amplitude can be minimized.

  The specific configuration of the control device 15 is the same as in FIG. The pressure vibration amplitudes from the pressure sensors 13 and 141 to 148 are stored in the storage unit 1511, and the pressure vibration amplitudes of the pressure sensors 13 and 141 to 148 before and after operating the opening adjustment valves 171 to 174 and 191 to 193 are compared. The control part which compares in the part 1512, determines the new opening degree of the opening degree adjustment valves 171-174, 191-193 from the comparison result, and controls these opening degree adjustment valves 171-174,191-193 152 may be provided.

  As means for determining the opening degree of the opening degree adjusting valves 171 to 174 and 191 to 193, the control device 15 uses the pressure vibration signals from the pressure sensors 13 and 141 to 148 to generate sound generated in the steam system. The vibration mode can be calculated, and the control device can determine a new opening in order from the opening adjustment valve provided at a position where the calculation result of the pressure vibration amplitude is large. From this acoustic vibration mode, the pressure vibration amplitudes at the positions of the opening adjustment valves 171 to 174 and 191 to 193 are obtained and controlled from the opening adjustment valve having the larger pressure vibration. By using this method, the optimum opening degree of the opening degree adjusting valves 171 to 174 and 191 to 193 can be obtained in a shorter time.

Example 5:
FIG. 8 is a configuration diagram of a steam system of a boiling water reactor according to the fifth embodiment of the present invention. The steam 2 generated inside the reactor pressure vessel 1 is removed by the corrugated plate 4 inside the steam dryer 3 and then flows into the steam dome 6 surrounded by the lid 5 of the reactor pressure vessel 1. To do. The removed moisture passes through the drain pipe 7 and is discharged below the steam dryer 3. Thereafter, the steam 2 flows from the nozzle 8 through the steam pipe 9 into the high-pressure turbine 10. The steam pipe 9 is provided with a branch pipe 20, and the branch pipe 20 is provided with opening degree adjusting valves 21, 22, and 23. The branch pipe 20 is connected to the outlet of the high-pressure turbine 10 through opening degree adjusting valves 21 and 23. Further, the branch pipe 20 is connected to a feed water heater (not shown) used for heating feed water to the reactor pressure vessel 1 via an opening degree adjusting valve 22. Pressure sensors 13 and 14 are attached to a vapor phase space (steam system) from the steam dome 6 through the nozzle 8 and the steam pipe 9 to the high pressure turbine 10. Here, either one of the pressure sensors 13 or 14 or a plurality of pressure sensors may be installed. Moreover, you may install multiple branch piping 20 and the opening degree adjustment valves 21-23, respectively. Only one of the opening adjustment valves 22, 23 may be used. The pressure vibration signals from the pressure sensors 13 and 14 are processed by the control device 15 and used to control the opening degree of the opening degree adjusting valves 21 to 23.

  This embodiment is characterized in that a branch pipe 20 is provided in the steam pipe 9 and an opening degree adjusting valve 21 is provided in the branch pipe 20. The branch pipe 20 and the opening degree adjusting valve 21 function in the same manner as the Helmholtz resonance pipe, and by adjusting the opening degree of the opening degree adjusting valve 21, the acoustic impedance of the branch pipe 20 changes and resonates, so that the steam pipe The acoustic resonance mode generated in 9 can be attenuated. In the present embodiment, the steam that has passed through the opening adjustment valve 21 is recovered by heating the feed water to the outlet of the high-pressure turbine 10 and the reactor pressure vessel 1. In this embodiment, the acoustic resonance mode can be attenuated only by changing the piping configuration without using the Helmholtz resonance tube. The specific configuration of the control device 15 is the same as in FIG. The opening degree of the opening degree adjusting valves 21 to 23 can be determined in the same manner as other examples. However, in the case of the present embodiment, since the opening degree of the opening degree adjusting valves 21 to 23 affects the electric output and thermal efficiency of the boiling water reactor, an upper limit is set beforehand on the opening degree of these opening degree adjusting valves. It is necessary to prepare.

Example 6:
FIG. 9 is a configuration diagram of a steam system of a boiling water reactor according to Embodiment 6 of the present invention. The steam 2 generated inside the reactor pressure vessel 1 is removed by the corrugated plate 4 inside the steam dryer 3 and then flows into the steam dome 6 surrounded by the lid 5 of the reactor pressure vessel 1. To do. The removed moisture passes through the drain pipe 7 and is discharged below the steam dryer 3. Thereafter, the steam 2 flows from the nozzle 8 through the steam pipe 9 into the high-pressure turbine 10. The steam pipe 9 is provided with a Helmholtz resonance pipe 12 having a plurality of opening adjustment valves 11. Pressure sensors 13 and 14 are attached to a vapor phase space (steam system) from the steam dome 6 through the nozzle 8 and the steam pipe 9 to the high pressure turbine 10. Here, either one of the pressure sensors 13 or 14 or a plurality of pressure sensors may be installed. The pressure vibration signals from the pressure sensors 13 and 14 are processed by a signal processing unit in the control device 15 and used for controlling the opening of the opening adjusting valve 11. The configuration of the control device 15 is the same as that of the first embodiment, and redundant description is avoided.

  FIG. 10 is a configuration diagram of the Helmholtz resonance tube 12 of the present embodiment. Each of the plurality of inlet pipes 121 connected to the steam pipe 9 is provided with an opening degree adjusting valve 11, and these inlet pipes 121 are connected by a single resonance damping pipe 122. By assuming that the sum of the cross-sectional areas of the plurality of inlet pipes is An and the volume of the resonance attenuating pipe 122 is V, the resonance frequency can be expressed approximately by the equation (1) in this case as well. The resonance attenuation pipe 122 may be an annulus-shaped container arranged so as to surround the steam pipe 9 in addition to the pipe as shown in FIG.

  In this embodiment, even when there is no space around the steam pipe 9, the Helmholtz resonance pipe 12 can be compactly arranged along the steam pipe 9. Further, since the plurality of inlet pipes are provided, the sum An of the sectional areas of the inlet pipes can be increased, and the attenuation rate of the pressure vibration amplitude can be increased. When applied at the time of increased output of a boiling water reactor, the number of valves is reduced by using a large, large-capacity safety valve with a large flow path area compared to before the increased output, and the remaining multiple valve seats are used. A means such as installing a Helmholtz resonance tube is also possible.

  In Examples 1 to 6 described above, the opening adjustment valve 11 is attached to the inlet pipe 121 and the control device 15 is attached. Once the opening degree is determined, the opening adjustment valve 11 is then opened. The degree may be fixed and the control device 15 may be removed and used.

  FIG. 11 is a frequency vs. sound pressure characteristic diagram for explaining the effect of the embodiment of the present invention, and is a typical element test result when a Helmholtz resonance tube is used. The vertical axis in the figure is the sound pressure on the surface of the steam dryer, and when there is no Helmholtz resonance tube, a low frequency pressure oscillation peak occurs. It can be seen that the pressure vibration peak can be effectively damped by matching the resonance frequency of the Helmholtz resonance tube with this low frequency pressure vibration peak.

The block diagram of the steam system of the boiling water reactor of Example 1 of this invention. FIG. 2 is a vertical side view of a Helmholtz resonance tube used in an embodiment of the present invention. The dimension vs. resonant frequency characteristic figure of the Helmholtz resonance tube used for the Example of this invention. The processing function block diagram of the control apparatus by the Example of this invention. The block diagram of the steam system of the boiling water reactor of Example 2 of this invention. The block diagram of the steam system of the boiling water reactor of Example 3 of this invention. The block diagram of the steam system of the boiling water reactor of Example 4 of this invention. The block diagram of the steam system of the boiling water reactor of Example 5 of this invention. The block diagram of the steam system of the boiling water reactor of Example 6 of this invention. Fig. 10 is a vertical side view of a Helmholtz resonance tube used in Example 6 of the present invention. FIG. 6 is a frequency versus sound pressure characteristic diagram illustrating the effect of the embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Steam, 3 ... Steam dryer, 4 ... Corrugated plate, 5 ... Reactor pressure vessel lid, 6 ... Steam dome, 7 ... Drain pipe, 8 ... Nozzle, 9, 91-94 ... Steam piping, 10 ... high pressure turbine, 11 ... opening adjustment valve, 12, 12A, 12B ... Helmholtz resonance pipe, 121 ... inlet piping, 122 ... resonance damping pipe, 13, 14, 141-148 ... pressure sensor, 15 ... control Device 151: Signal processing unit 1511 ... Storage unit 1512 ... Comparison unit 152 ... Control unit 16 ... Steam header 171-174, 191-193 ... Opening adjustment valve 20 ... Branch piping 21-23 ... Opening adjustment valve.

Claims (14)

  In a boiling water reactor comprising a reactor pressure vessel, a steam pipe for transporting steam generated in the reactor pressure vessel, and a high-pressure turbine connected to the steam pipe and driven by the steam, A boiling water nuclear reactor in which a Helmholtz resonance tube is installed in a steam system including a steam phase portion of the reactor pressure vessel and the steam pipe.   In a boiling water reactor comprising a reactor pressure vessel, a steam pipe for transporting steam generated in the reactor pressure vessel, and a high-pressure turbine connected to the steam pipe and driven by the steam, A Helmholtz resonance pipe installed in a steam system including a steam phase portion of the reactor pressure vessel and the steam pipe, and having a regulating valve in an inlet pipe thereof, a pressure sensor for detecting pressure vibration of the steam system, and the pressure sensor A boiling water reactor comprising control means for adjusting the opening of the regulating valve in accordance with the pressure vibration detected in step (b).   3. The boiling water reactor according to claim 1, wherein the Helmholtz resonance tube is installed in a portion of the steam system having a large pressure oscillation amplitude.   4. The boiling water reactor according to claim 1, wherein the Helmholtz resonance tube is installed in the steam phase portion of the reactor pressure vessel. 5.   The boiling water nuclear reactor according to any one of claims 1 to 4, wherein the Helmholtz resonance tube is installed in the steam pipe close to a steam outlet of the pressure vessel.   In a boiling water reactor comprising a reactor pressure vessel, a steam pipe for transporting steam generated in the reactor pressure vessel, and a high-pressure turbine connected to the steam pipe and driven by the steam, An opening degree adjusting valve for adjusting the opening degree of the connecting pipe and / or the branch pipe branching from the main channel pipe connecting the steam system main channel pipes composed of the steam phase portion of the reactor pressure vessel and the steam pipe. A boiling water reactor characterized in that   7. The pressure sensor for detecting the pressure vibration amplitude of the steam system, a storage device for storing the detected value of the pressure vibration amplitude, and the pressure vibration before and after operating the adjusting valve according to claim 2 or 6. A comparison device for comparing the amplitude, and a control device for determining a new opening of the adjustment valve in a direction to decrease the pressure vibration amplitude from the comparison result of the comparison device and outputting a control signal to the adjustment valve A boiling water reactor characterized by that.   In a boiling water reactor comprising a reactor pressure vessel, a steam pipe for transporting steam generated in the reactor pressure vessel, and a high-pressure turbine connected to the steam pipe and driven by the steam, An inlet pipe of a Helmholtz resonance pipe provided in a steam system composed of the steam phase portion of the reactor pressure vessel and the steam pipe, or a connection pipe and / or the main flow path connecting main flow pipes constituting the steam system An opening adjustment valve provided in a branch pipe branched from the pipe, and detecting the pressure vibration amplitude in the steam system, storing the detected pressure vibration amplitude, and operating the opening adjustment valve A step of comparing the pressure vibration amplitude before and after, a step of determining a new opening of the opening adjustment valve based on the comparison result, and the opening adjustment valve according to the determined opening. Gosuru boiling water reactor method of the acoustic vibration suppression, characterized in that it comprises the step.   The step of obtaining a sensitivity of the pressure vibration amplitude with respect to a valve opening adjustment amount of the opening adjusting valves, and a new opening in order from the obtained valve having the highest sensitivity. And a step of controlling the opening adjustment valve according to the determined new opening, and a method for suppressing acoustic vibrations in a boiling water reactor.   9. The step of determining a new opening in order from an opening adjusting valve provided with a plurality of the opening adjustment valves and arranged at a position where the pressure vibration amplitude is large, and according to the determined new opening A method for suppressing acoustic vibrations in a boiling water reactor, comprising a step of controlling the opening adjustment valve.   In a boiling water reactor comprising a reactor pressure vessel, a steam pipe for transporting steam generated in the reactor pressure vessel, and a high-pressure turbine connected to the steam pipe and driven by the steam, A Helmholtz resonance pipe having a plurality of inlet pipes and a single resonance attenuating pipe connecting the plurality of inlet pipes is installed in the steam system including the steam phase portion of the reactor pressure vessel and the steam pipe. Boiling water reactor.   12. The boiling water reactor according to claim 11, wherein the Helmholtz resonance tube is installed in a portion of the steam system having a large pressure oscillation amplitude.   12. The boiling water reactor according to claim 11, wherein the Helmholtz resonance tube is installed in the steam phase portion of the reactor pressure vessel.   12. The boiling water reactor according to claim 11, wherein the Helmholtz resonance tube is installed in the steam pipe near the steam outlet of the pressure vessel.

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