JP5592522B1 - Exhaust system - Google Patents

Abstract

An exhaust system capable of safely releasing hydrogen gas staying on the top floor of a reactor building to the outside in an emergency is provided.
An exhaust device 1 is connected to an uppermost wall surface of a reactor building 50 having one end portion accommodating a nuclear reactor, and an exhaust cylinder that releases the gas generated in the reactor to the outside at the other end portion. 60, a cylindrical discharge line 10 that forms a gas movement path from the reactor building 50 to the exhaust stack 60, and a gas release path 10 provided in the discharge line 10, Pressure release diaphragm plates 12a and 12b for restricting movement, a nitrogen gas cylinder 18 provided outside the reactor building 50 for supplying an inert gas into the discharge line 10, and a pressure release diaphragm plate 12a by the pressure of the inert gas, And a cutter for breaking 12b.
[Selection] Figure 3

Description

  The present invention relates to an exhaust device for releasing hydrogen gas staying on the top floor of a reactor building to the outside.

  If a natural disaster such as an earthquake or tsunami occurs that could compromise the safety of the reactor, it is necessary to stop the operation of the reactor immediately. However, if the reactor for cooling the reactor breaks down and the reactor cannot be cooled, there is a possibility that the core melts. If the core melts, hydrogen gas is generated accordingly. Because hydrogen gas is lighter than air, it stays on the top floor of the reactor building. Here, if the hydrogen gas staying in the reactor building is left unattended, it may ignite and explode, so it is necessary to release the hydrogen gas from the reactor building.

  Conventionally, as this type of technology, there is a technology described in Patent Document 1. According to Patent Document 1, the hydrogen concentration in a building in a nuclear power generation facility is monitored by a hydrogen detector, and when hydrogen is detected, an inert gas is ejected into the building by an inert gas ejection device. A technology that fills a mixed gas of hydrogen / air / inert gas and releases the mixed gas into the atmosphere through an exhaust pipe while controlling the hydrogen concentration in the mixed gas to a safe concentration below the explosion limit. Proposed.

JP 2012-225823 A

  However, since the technology of Patent Document 1 uses an electric device, it may not operate when a natural disaster such as an earthquake or tsunami occurs and a power failure occurs. Here, it is conceivable that an opening / closing device is provided on the uppermost floor of the nuclear reactor building, and an operator opens the opening / closing device. However, in this case, since the worker moves up the floor and opens the switchgear and then evacuates, there is a possibility that there will be no time margin. It is also conceivable that the opening / closing device can be opened by an electric method in addition to manual operation. However, if it is electric, the possibility of sparks and ignition of hydrogen gas cannot be denied.

  An object of the present invention is to solve such problems and to provide an exhaust device that can safely discharge the hydrogen gas retained on the top floor of a reactor building to the outside in an emergency.

  In order to achieve the above object, the present invention has the following configuration.

  (1) A cylindrical discharge line that connects the top floor wall of the reactor building and the exhaust stack, a pressure release diaphragm plate that is provided in the discharge line and regulates gas movement, and provided outside the reactor building An exhaust system comprising: an inert gas supply unit that supplies an inert gas into the discharge line; and a breaker that breaks the pressure release diaphragm plate by the pressure of the inert gas.

  According to (1), when an operator operates the inert gas supply unit located on the ground outside the reactor building, the inert gas is supplied to the discharge line, and the pressure release diaphragm plate is moved by the pressure of the inert gas. Destroyed. As a result, since the discharge line 10 is opened, it is possible to safely release the hydrogen gas staying on the top floor of the reactor building in an emergency while ensuring the safety of workers, and the hydrogen explosion The possibility of causing such a situation can be reduced.

  (2) The exhaust system according to (1), further comprising a filter that is provided in the discharge line and that adsorbs a radioactive substance contained in a gas from the reactor building passing through the discharge line.

  According to (2), the surrounding environment can be maintained in a good state by discharging the gas passing through the discharge line after cleaning.

(3) In (1) and (2), two pressure release diaphragm plates are provided, the two pressure release diaphragm plates are arranged at a predetermined interval, and the inert gas supply unit is The inert gas is supplied to a sealed space formed between the two pressure release diaphragm plates, and the pressure in the sealed space is greater than or equal to a predetermined value by the inert gas supplied by the inert gas supply unit. The exhaust device according to claim 1 , wherein the two pressure release diaphragm plates are destroyed at the same time .

  According to (3), it is possible to easily secure a space for introducing an inert gas.

  (4) The exhaust apparatus according to any one of (1) to (3), wherein the inert gas is nitrogen gas.

  According to (4), the danger of explosion can be reduced by mixing nitrogen gas with hydrogen gas.

  (5) In (1) to (4), the exhaust line is inclined upward from the reactor building side toward the exhaust stack side.

  According to (5), the hydrogen gas accumulated in the reactor building can be reliably moved to the exhaust tube side.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to discharge | release the hydrogen gas collected on the top floor of the reactor building to the exterior safely at the time of emergency.

It is a top view which shows arrangement | positioning of the exhaust apparatus 1 in one Embodiment of this invention. 2 is a front view of a nuclear reactor building 50. FIG. It is a side view including the partial cross section which shows the structure of the exhaust apparatus in one Embodiment of this invention. It is explanatory drawing which shows the structure of the diaphragm apparatus. It is explanatory drawing which shows the structure of the pressure release diaphragm plate 12a. 11 is an explanatory view showing the operation of the diaphragm device 12. FIG. It is explanatory drawing which shows the other structure of the diaphragm apparatus. It is explanatory drawing which shows the structure of the pressure release diaphragm plate in the other structure of the diaphragm apparatus. It is explanatory drawing which shows operation | movement of the other structure of the diaphragm apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view showing the arrangement of the exhaust device 1 in one embodiment of the present invention, and FIG. 2 is a front view of a reactor building 50 showing the arrangement of the exhaust device 1 in one embodiment of the present invention. As shown in FIG. 1, a reactor building 50, a turbine building 52, a waste treatment building 54, a control room building 56, a service building 58, and the like are built in the site of the nuclear power plant.

  The reactor building 50 accommodates a nuclear reactor, a spent fuel pool, and the like. The turbine building 52 houses a turbine that is heated by a nuclear reactor and is rotated by vaporized water, a generator that generates electric power by rotating the turbine, and the like. The waste treatment building 54 accommodates equipment for treating waste generated in the reactor building 50 and the turbine building 52. For example, a filter for removing dust from air ventilated in a building, a filtration device for filtering waste water, and the like are accommodated in the waste treatment building 54. The control room building 56 houses a central control device that monitors the operation of the nuclear power plant. The service building 58 has returned from the radiation control area, where the workers change into equipment for entering and exiting the radiation control area, for example, the radiation control area such as the reactor building 50, the turbine building 52, the waste treatment building 54, etc. It accommodates equipment for collecting equipment.

  Further, the reactor building 50 includes an exhaust pipe 60, and the exhaust pipe 60 ventilates the reactor building 50. The exhaust pipe 60 is erected on the rooftop of the floor below the top floor and on the side of the top floor of the reactor building 50. Moreover, as shown in FIG. 2, the exhaust apparatus 1 is installed between the exhaust pipe 60 and the top floor of the reactor building 50. For example, the exhaust device 1 sends out hydrogen gas staying on the uppermost floor of the reactor building 50 to the exhaust cylinder 60 and releases the hydrogen gas from the exhaust cylinder 60 to the outside.

  FIG. 3 is an explanatory diagram showing the configuration of the exhaust device 1. The exhaust device 1 includes a discharge line 10, a diaphragm device 12, a filter 14, a pipe 16, and a nitrogen gas cylinder 18 corresponding to an inert gas supply unit.

  The discharge line 10 is a cylindrical member that connects the exhaust stack 60 and the reactor building 50, and one end portion of the discharge line 10 is fixed to the upper part of the side wall of the top floor in the reactor building 50, The other end is fixed to the side wall of the exhaust tube 60. At this time, the discharge line 10 is fixed so as to have an upward slope toward the exhaust tube 60 side. According to this embodiment, the diameter of the discharge line 10 is 1 m.

  The diaphragm device 12 is installed at one end of the discharge line 10. The diaphragm device 12 includes two pressure release diaphragm plates 12a and 12b. The pressure release diaphragm plates 12a and 12b are installed so as to face each other at a predetermined interval. By installing the pressure release diaphragm plates 12a and 12b, a sealed space surrounded by the discharge line 10 and the pressure release diaphragm plates 12a and 12b is formed at one end of the discharge line 10. The pressure release diaphragm plates 12a and 12b are configured to be broken at the same time when the pressure in the sealed space exceeds a predetermined value. The inner surfaces of the pressure release diaphragm plates 12a and 12b are coated with an electrostatic resin for preventing sparks and static electricity.

  The filter 14 is installed at the other end of the discharge line 10 and collects and adsorbs radioactive substances from the exhaust gas that has passed through the discharge line 10 from the reactor building 50. As the filter 14, zeolite is applicable.

  One end of the pipe 16 is fixed to one end of the discharge line 10, communicates with a sealed space formed by the pressure release diaphragm plates 12a and 12b, and a nitrogen gas cylinder 18 is attached to the other end. The nitrogen gas cylinder 18 and the pipe 16 are installed on the outside ground part of the reactor building 50, and when an operator manually opens the gas plug of the nitrogen gas cylinder 18, nitrogen gas is supplied into the sealed space. .

  4 is a side sectional view showing the configuration of the diaphragm device 12, and FIG. 5 is a front view of the pressure release diaphragm plate 12a viewed from the inside.

  As shown in FIG. 4, the diaphragm apparatus 12 includes a breaking member 28 and a cutter 30 in addition to the pressure release diaphragm plate 12a and the pressure release diaphragm plate 12b.

  The pressure release diaphragm plate 12 a includes a diaphragm plate 20, a sheet material 21, a fixing ring 22, a support ring 24, and a thread-like member 26. The diaphragm plate 20 is made of, for example, a circular thin film made of a rolled copper plate. The fixing ring 22 is a flat ring member having an outer diameter substantially equal to the inner diameter of the discharge line 10 and an inner diameter smaller than that of the diaphragm plate 20. The support ring 24 is a flat ring member having an outer diameter slightly larger than that of the diaphragm plate 20 and an inner diameter substantially equal to the inner diameter of the fixing ring 22. Screw holes are formed in the surface of the fixing ring 22, and through holes are formed in the outer peripheral portion of the diaphragm plate 20 and the surface of the support ring 24. Then, the diaphragm plate 20 is placed on the fixing ring 22 so that the screw hole of the fixing ring 22 and the through hole of the diaphragm plate 20 coincide with each other. Further, a ring-shaped packing made of silicon rubber is placed on the diaphragm plate 20. The support ring 24 is placed on the packing so that the through hole of the diaphragm plate 20 and the through hole of the support ring 24 coincide with each other, and are screwed into the through hole with bolts. Thereby, the diaphragm plate 20 is clamped by the fixing ring 22 and the support ring 24, and the pressure release diaphragm plate 12a is completed.

  As shown in FIG. 5, the sheet material 21 is a small-diameter circular member that is attached to the center portion of the surface of the diaphragm plate 20 on the fixing ring 22 side. One end of the thread-like member 26 is supported by the sheet material 21 and is disposed at the center of the diaphragm plate 20. The cutter 30 is a blade member with a sharp tip, and cuts the diaphragm plate 20. The cutter 30 is disposed inside the support ring 24, and the tip portion faces the diaphragm plate 20 in a normal state.

  Since the pressure release diaphragm plate 12b is the same type as the pressure release diaphragm plate 12a, the description of the pressure release diaphragm plate 12b is omitted.

  Further, as shown in FIG. 4, the breaking member 28 is formed of a U-shaped linear member, a cut is formed in the center portion, and by applying tension in a direction in which both ends of the U shape are pulled together. It has a structure that breaks into two.

  When the diaphragm device 12 is fixed to one end portion of the discharge line 10, first, the pressure release diaphragm plate 12 b is fixed to one end portion of the discharge line 10. At this time, the thread-like member 26 faces the one end side (reactor building side) of the discharge line 10. Next, the other end portion of the thread-like member 26 is fixed to one end portion of the breaking member 28.

Next, the fixing ring 22 of the pressure release diaphragm plate 12 a is disposed at one end of the discharge line 10. Next, the other end portion of the thread-like member 26 extending from the diaphragm plate 20 of the pressure release diaphragm plate 12 a is fixed to the other end portion of the breaking member 28. Then, by attaching the diaphragm plate 20 of the pressure release diaphragm plate 12a, the packing and the support ring 24 to the fixing ring 22 of the pressure release diaphragm plate 12a, the pressure release diaphragm plate 12a is disposed in the discharge line 10. Further, after adjusting the position of the pressure release diaphragm plate 12 a so that the thread-like member 26 is stretched in the discharge line 10, the pressure release diaphragm plate 12 a is fixed in the discharge line 10. Further, a cutter 30 is disposed inside the support ring 24 of the pressure release diaphragm plate 12a.
Thereby, the diaphragm apparatus 12 is installed in the one end part of the discharge line 10, and the movement of the gas between the exhaust pipe 60 and the reactor building 50 in the discharge line 10 is controlled by the pressure release diaphragm plates 12a and 12b.

  Next, the operation of the diaphragm device 12 will be described. In a normal state, an operator opens the gas stopper of the nitrogen gas cylinder 18 for a short time, encloses nitrogen gas in a sealed space formed at one end of the discharge line 10 by the diaphragm device 12, and reduces the pressure in the sealed space. Set a little higher than atmospheric pressure. Thereby, the normal airtightness in the diaphragm apparatus 12 is ensured, and the discharge line 10 is shut off.

  In addition, when a situation occurs that may impair the safety of the nuclear reactor due to a large natural disaster such as an earthquake or a tsunami, the worker opens the gas plug of the nitrogen gas cylinder 18. As a result, nitrogen gas is supplied to the diaphragm device 12 installed at one end of the discharge line 10 via the pipe 16. When nitrogen gas is supplied into the sealed space formed by the diaphragm device 12 and the pressure in the sealed space increases, the diaphragm plate 20 of the pressure release diaphragm plate 12a is on one end side of the discharge line 10 (reactor building side). The diaphragm plate 20 of the pressure release diaphragm plate 12b swells to the other end side (exhaust tube side) of the discharge line 10. Further, when the diaphragm plate 20 swells, tension is applied to the breaking member 28 via the thread-like members 26, 26, and the breaking member 28 is eventually broken.

  When the breaking member 28 breaks, the tension by the thread-like members 26, 26 applied to the diaphragm plate 20 is released, so that the central portion of the diaphragm plate 20 rapidly expands as shown in FIG. The diaphragm plate 20 of 12a and the diaphragm plate 20 of the pressure release diaphragm plate 12b abut against the cutter 30 substantially simultaneously. Thereby, the diaphragm plate 20 of the pressure release diaphragm plate 12a and the diaphragm plate 20 of the pressure release diaphragm plate 12b are torn substantially simultaneously, and the discharge line 10 is opened. Thus, the piping 16 and the nitrogen gas cylinder 18 correspond to a gas supply unit, and the nitrogen gas cylinder 18 and the cutter 30 correspond to a destruction unit.

  When the discharge line 10 is opened, the hydrogen gas staying on the uppermost floor of the reactor building 50 passes through the discharge line 10, the radioactive material is removed by the filter 14, and is sent to the exhaust pipe 60. Released into the atmosphere.

  By the way, gas lighter than air tends to gather on the top floor of the reactor building 50. For example, hydrogen gas tends to gather. Moreover, when the core melts, a lot of hydrogen gas is generated and stays on the uppermost floor of the reactor building 50. Therefore, according to the present embodiment, the diaphragm apparatus 12 is remotely operated by an operator manually opening the gas plug of the nitrogen gas cylinder 18 on the outside of the reactor building 50, and the pressure release diaphragm plates 12a and 12b. The diaphragm plate 20 is destroyed. Thereby, since the discharge line 10 is opened, it becomes possible to discharge the hydrogen gas in the reactor building 50 to the outside while ensuring the safety of workers. Thereby, if core melting occurs, it becomes possible to prevent the hydrogen gas from filling the reactor building 50, and the possibility of causing a situation such as a hydrogen explosion can be reduced.

  Moreover, since the diaphragm apparatus 12 operates with nitrogen gas and does not operate electrically, the hydrogen gas in the reactor building 50 is not ignited.

  Further, by further providing the filter 14 in the discharge line 10, it is possible to discharge after removing the radioactive substance contained in the hydrogen gas passing through the discharge line 10. Thereby, the surrounding environment can be maintained in a favorable state.

  In addition, two pressure release diaphragm plates 12a and 12b are provided. The pressure release diaphragm plates 12a and 12b are arranged at a predetermined interval, and nitrogen gas is supplied between the pressure release diaphragm plates 12a and 12b. Therefore, it is possible to easily secure a space for introducing nitrogen gas.

  Further, by introducing nitrogen gas, the danger of explosion can be reduced by mixing the nitrogen gas with the hydrogen gas.

  Further, since the discharge line 10 is inclined upward from the reactor building 50 side toward the exhaust stack 60 side, the hydrogen gas generated in the reactor building 50 can be reliably moved to the exhaust stack 60 side. become.

  As mentioned above, although embodiment of this invention was described, embodiment of this invention is not restricted to embodiment mentioned above. For example, in the embodiment described above, the cutter 30 is used to break the diaphragm plate 20, but if both the diaphragm plates 20 of the pressure release diaphragm plates 12a and 12b can be broken, the cutter 30 is not used and nitrogen is used. You may make it tear the diaphragm board 20 only with the pressure by gas. In the above-described embodiment, the pressure release diaphragm plates 12a and 12b are configured to break the diaphragm plate 20 at the same time. However, if both of the pressure release diaphragm plates 12a and 12b can be broken at the same time, It may not be necessary, and it may be broken after a time difference.

  Moreover, the diaphragm apparatus 12 is not restricted to the structure which breaks both the diaphragm plates 20 and 20 provided double.

  FIG. 7 is an explanatory view showing another configuration of the diaphragm device 12. In addition, about the member of the same structure and the same function as the diaphragm apparatus 12 shown in FIGS. 4-6, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. 7 includes a pressure release diaphragm plate 12a, a pressure release diaphragm plate 12b, and a thread-like member 36. The pressure release diaphragm plate 12a includes the diaphragm plate 20, the fixing ring 32, and the like. The support ring 34 is provided.

  The fixing ring 32 is a flat ring member whose outer diameter is substantially equal to the inner diameter of the discharge line 10. A circular hole 32a is formed at the center of the fixing ring 32, and a cylindrical protrusion standing on the center of the surface of the fixing ring 32 on the exhaust tube 60 side so as to surround the hole 32a. A portion 32b is formed.

  The support ring 34 is a lid that fits the protrusion 32 b, and the diaphragm plate 20 is attached to the protrusion 32 b side of the support ring 34 so as to cover the opening of the support ring 34. The hole 32 a is closed by the diaphragm plate 20 by fitting the support ring 34 to the protrusion 32 b of the fixing ring 32.

  As shown in FIG. 8, the pressure release diaphragm plate 12 b is obtained by forming a thin portion 20 a having a diameter slightly smaller than the inner diameter of the support ring 24 on the diaphragm plate 20 in the pressure release diaphragm plate 12 b shown in FIG. 5.

  Further, the thread-like member 36 is stretched between the central part of the diaphragm plate 20 of the pressure release diaphragm plate 12a and the central part of the diaphragm plate 20 of the pressure release diaphragm plate 12b in a slightly relaxed state.

  In a normal state, an operator opens the gas stopper of the nitrogen gas cylinder 18 for a short time, encloses nitrogen gas in a sealed space formed at one end of the discharge line 10 by the diaphragm device 12, and reduces the pressure in the sealed space. Set a little higher than atmospheric pressure. Thereby, the airtightness in the normal time in the diaphragm apparatus 12 is ensured, and the diaphragm plate 20 of the pressure release diaphragm plate 12a is maintained in a state of being in close contact with the protruding portion 32b.

  Further, when the worker opens the gas stopper of the nitrogen gas cylinder 18, nitrogen gas is supplied to the diaphragm device 12 installed at one end of the discharge line 10 through the pipe 16. When nitrogen gas is supplied into the sealed space formed in the diaphragm device 12 and the pressure in the sealed space increases, the diaphragm plate 20 of the pressure release diaphragm plate 12a is connected to one end side of the discharge line 10 (reactor building The diaphragm plate 20 of the pressure release diaphragm plate 12b swells to the other end side (exhaust tube side) of the discharge line 10. Then, the thin portion 20a is first broken in the diaphragm 20 of the pressure release diaphragm 12b, and the internal pressure between the pressure release diaphragm 12a and the pressure release diaphragm 12b is greatly reduced. Thereby, the pressure which presses to the fixed ring 32 side concerning the support ring 34 falls. Further, when the diaphragm plate 20 of the pressure release diaphragm plate 12b is torn, tension is applied to the diaphragm plate 20 of the pressure release diaphragm plate 12a via the thread-like member 36, and the support ring 34 is pulled toward the exhaust tube 60 side. As a result, as shown in FIG. 9, the support ring 34 falls out of the protrusion 32 b and the discharge line 10 is opened.

  With this configuration, it is possible to release hydrogen gas in the reactor building 50 to the outside while ensuring the safety of workers. Thereby, if core melting occurs, it becomes possible to prevent the hydrogen gas from filling the reactor building 50, and the possibility of causing a situation such as a hydrogen explosion can be reduced. In addition, the support ring 34 can be prevented from falling to the reactor building 50 side.

DESCRIPTION OF SYMBOLS 1 Exhaust device 10 Release line 12 Diaphragm device 12a Pressure release diaphragm plate 12b Pressure release diaphragm plate 14 Filter 16 Piping 18 Nitrogen gas cylinder 20 Diaphragm plate 21 Sheet material 22 Fixing ring 24 Support ring 26 Filamentary member 28 Breaking member 30 Cutter 40 Control room building 50 Reactor building 52 Turbine building 54 Waste treatment building 56 Control room building 58 Service building 60 Exhaust pipe

Claims (5)

One end is connected to the wall of the uppermost floor of the reactor building that houses the reactor, and the other end is connected to an exhaust pipe that releases the gas generated in the reactor to the outside. A cylindrical discharge line that forms a path of gas movement to the exhaust stack;
A pressure release diaphragm plate provided in the discharge line for regulating gas movement from the reactor building to the exhaust stack;
An inert gas supply unit provided outside the reactor building and supplying an inert gas into the discharge line;
An exhaust apparatus comprising: a breaking portion that breaks the pressure release diaphragm plate by the pressure of the inert gas.   The exhaust system according to claim 1, further comprising a filter that is provided in the discharge line and that adsorbs a radioactive substance contained in a gas from the reactor building passing through the discharge line. Two pressure release diaphragm plates are provided,
The two pressure release diaphragm plates are arranged at a predetermined interval,
The inert gas supply unit supplies the inert gas to a sealed space formed between the two pressure release diaphragm plates,
The destruction part destroys the two pressure release diaphragm plates at the same time when the pressure in the sealed space becomes a predetermined value or more by the inert gas supply by the inert gas supply part. The exhaust apparatus according to claim 1 or 2.   The exhaust apparatus according to any one of claims 1 to 3, wherein the inert gas is nitrogen gas.   The exhaust system according to any one of claims 1 to 4, wherein the discharge line is inclined upward from the reactor building side toward the exhaust stack side.

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