JP2013101012A - Reactor container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor container for much more quickly starting a work in a reactor pressure vessel in regular inspection, and for discharging combustible gas in a dry well head when an abnormal event occurs.SOLUTION: In a reactor container 2, a dry well head 4 is attached to the upper end of a reactor body container 3 so as to be attached and detached, a hydrogen gas discharge path 13 is disposed on the internal surface of the dry well head 4, a gas inlet 15 is disposed at the apex of an area 6 inside the dry well head 4, a hydrogen gas discharge path 14 is installed on the internal surface of the top end of the reactor body container 3, and connected to a hydrogen gas discharge pipe 16 attached to the external surface of the reactor body container 3, the separated hydrogen gas discharge path 13 and the hydrogen gas discharge path 14 are brought into contact with each other when the dry well head 4 is attached to the reactor body container 3, and the hydrogen gas discharge path 13 is communicated with the hydrogen gas discharge path 14.

Description

  The present invention relates to a reactor containment vessel, and more particularly to a reactor containment vessel suitable for application to a boiling water reactor.

  In a boiling water reactor, a reactor containment vessel surrounds a reactor pressure vessel containing a core, and cooling water is filled in the reactor pressure vessel. Cooling water is supplied into a plurality of fuel assemblies loaded in the core and heated by heat generated by nuclear fission of nuclear fuel material contained in the fuel assemblies, and a part of the cooling water becomes steam. The steam generated in the core is discharged from the reactor pressure vessel to the main steam pipe connected to the reactor pressure vessel, and is guided to the turbine through the main steam pipe.

  In this boiling water reactor, for example, it is assumed that a crack penetrating through the main steam pipe has occurred in the reactor containment vessel and an accident of loss of coolant, which is an abnormal event, has occurred. The high-temperature cooling water in the reactor pressure vessel is discharged as a high-temperature steam from the crack in the main steam pipe to the dry well in the reactor containment vessel. In order to avoid a drop in the water level in the reactor pressure vessel when a coolant loss accident occurs, the emergency core cooling system is activated and cooling water is injected into the reactor pressure vessel.

  In order to suppress the pressure rise in the dry well due to the release of steam, a pressure suppression chamber is provided in the reactor containment vessel, and a pressure suppression pool filled with cooling water is formed in the pressure suppression chamber. Yes. Vapor discharged into the dry well is discharged into the cooling water in the pressure suppression chamber through the vent passage and condensed.

  The steam released into the dry well contains hydrogen gas and oxygen gas generated by radiolysis of cooling water in the reactor pressure vessel. For this reason, the concentration of hydrogen gas in the reactor containment vessel increases. If the increase in the hydrogen gas concentration is left unattended, if the hydrogen gas concentration is 4 vol% or more and the oxygen gas concentration is 5 vol% or more in the reactor containment vessel, there is a risk that the hydrogen gas will explode.

  Japanese Patent Application Laid-Open No. 6-130170 discloses a static flammable gas treatment device (recombiner) for treating hydrogen gas in a boiling water reactor in a reactor containment vessel, specifically in a dry well. And disposing it in the air layer of the pressure suppression chamber. A catalyst layer containing a catalyst (for example, platinum, palladium, etc.) that promotes a binding reaction between hydrogen and gas is provided in the static combustible gas processing apparatus. Hydrogen gas contained in the steam released from the crack generated in the main steam pipe flows into the static combustible gas treatment device together with the steam and nitrogen gas enclosed in the reactor containment vessel, and static combustible. It is combined with oxygen by the action of the catalyst in the chemical gas treatment device to become water. Since the bonding reaction between hydrogen and oxygen is an exothermic reaction, the generated water becomes steam and is discharged from the static combustible gas processing apparatus.

  In addition, in order to treat hydrogen gas leaked from the containment vessel to the reactor building outside the containment vessel for some reason, a static combustible gas treatment device is installed in the reactor building outside the containment vessel. It has been proposed to arrange indoors (see JP 2009-69121 A).

  Light hydrogen gas tends to accumulate in the dry well head of the reactor containment vessel. For this purpose, a hydrogen gas discharge pipe that opens near the top of the dry well head is installed in the dry well head, and this pipe is connected to a cooler installed in the static containment cooling system pool. Connecting to a line is described in Japanese Patent Laid-Open No. 10-212477. In order to reduce the hydrogen gas concentration, platinum or palladium is coated on the inner surface of the vapor introduction line. When a coolant loss accident occurs, the hydrogen gas accumulated in the dry well head is sucked into the hydrogen gas discharge pipe together with the steam and nitrogen gas filled in the reactor containment vessel, and is introduced into the steam introduction line. It is burned. Hydrogen gas is treated by being combined with oxygen by the action of platinum or palladium on the inner surface of the steam introduction line. The steam that has flowed into the steam introduction line is condensed into water by a cooler, and this water is collected in a pool of a gravity drop emergency core cooling system provided in the reactor containment vessel. Non-condensable gas such as nitrogen gas flowing into the steam introduction line is guided to the pressure suppression chamber.

JP-A-6-130170 JP 2009-69121 A JP-A-10-212477

  As described in Japanese Patent Application Laid-Open No. 10-212477, the installation of a hydrogen gas discharge pipe opening near the top of the dry well head in the dry well head can discharge the hydrogen gas accumulated in the dry well head. If it pays attention to this viewpoint, it is a good structure. However, the structure described in Japanese Patent Laid-Open No. 10-212477, in which the hydrogen gas discharge pipe is installed in the dry well head, was loaded on the core in the reactor pressure vessel in the periodic inspection of the boiling water reactor. Start each operation in the reactor pressure vessel, such as replacement of the fuel assembly, replacement of the control rod installed in the reactor pressure vessel, and maintenance and inspection of the in-reactor structure installed in the reactor pressure vessel. It becomes a factor to delay. When performing these operations in the reactor pressure vessel, remove the dry well head, and then install the top lid of the reactor pressure vessel and the steam dryer and steam separator installed in the reactor pressure vessel, respectively. It is necessary to remove it and carry it out of the reactor containment vessel. In JP-A-10-212477, even if the dry well head is removed, if the hydrogen gas discharge pipe disposed in the dry well head is not removed, the upper cover of the reactor pressure vessel, the steam dryer, and the steam separator are provided. It cannot be carried out of the reactor containment vessel.

  It is necessary to remove the hydrogen gas discharge pipe before the reactor pressure vessel top lid, steam dryer and steam separator are carried out of the reactor containment vessel, and only for the time required to remove the hydrogen gas discharge pipe. The start of carrying out of the reactor pressure vessel top lid, steam dryer and steam separator to the outside of the containment vessel was delayed, replacement of fuel assemblies and control rods, and inside the reactor installed in the reactor pressure vessel There is a problem that the start of each operation in the reactor pressure vessel such as maintenance and inspection of the structure is delayed.

  It is an object of the present invention to be able to start the work in the reactor pressure vessel at the time of periodic inspection of the reactor earlier and to discharge the combustible gas in the dry well head at the time of an abnormal event. To provide a container.

A feature of the present invention that achieves the above-described object includes a reactor containment main body vessel that surrounds the reactor pressure vessel, and a dry well head that is removably attached to the upper end of the reactor containment main body vessel,
A first gas discharge passage is provided in the dry well head, a gas inlet of the first gas discharge passage is connected to a region in the dry well head, and a second gas discharge passage separated from the first gas discharge passage is an atom. When the dry well head is provided in the reactor containment main body vessel and the dry well head is attached to the reactor containment main body vessel, the upper end of the second gas discharge passage is disposed opposite to the lower end of the first gas discharge passage and the second gas discharge The passage is communicated with the first gas discharge passage, and the gas discharge pipe disposed outside the reactor containment main body vessel is connected to the second gas discharge passage.

  A first gas discharge passage is provided in the dry well head, a gas inlet of the first gas discharge passage is connected to a region in the dry well head, and a second gas discharge passage separated from the first gas discharge passage is an atom. An abnormal event occurs because the upper end of the second gas discharge passage is disposed opposite to the lower end of the first gas discharge passage and the second gas discharge passage is connected to the first gas discharge passage. Sometimes combustible gas that accumulates in the drywell head can be discharged into the reactor containment vessel. Furthermore, since the first gas discharge passage separated from the second gas discharge passage is provided in the dry well head, the dry well head is removed from the reactor containment main body container before the work in the reactor pressure vessel is performed. The first gas discharge passage is also removed from the reactor containment main body vessel together with the dry well head. For this reason, the work in the reactor pressure vessel during the periodic inspection of the reactor can be started earlier.

  According to the present invention, work in the reactor pressure vessel can be started earlier at the time of periodic inspection of the reactor, and the combustible gas in the dry well head of the reactor containment vessel at the time of an abnormal event can be discharged. Can do.

It is a block diagram of the reactor containment vessel of Example 1 which is one suitable Example of this invention. It is an enlarged view of the detailed structure of the combustible gas discharge passage shown in FIG. It is an enlarged view which shows the detailed structure of the combustible gas discharge passage provided in the nuclear reactor containment vessel of Example 3 which is another Example of this invention. It is an enlarged view which shows the detailed structure of the combustible gas discharge passage provided in the nuclear reactor containment vessel of Example 4 which is another Example of this invention.

  Examples of the present invention will be described below.

  A reactor containment vessel according to embodiment 1, which is a preferred embodiment of the present invention, will be described with reference to FIGS. 1 and 2. The reactor containment vessel of the present embodiment is a reactor containment vessel used for a boiling water reactor.

  The reactor containment vessel 2 of the present embodiment includes a reactor containment main body vessel 3, a dry well head 4 as an upper lid, a combustible gas treatment device 7, and a containment vessel vent pipe 18. The dry well head 4 is detachably attached to the upper end of the reactor containment main body vessel 3. A dry well 20 and a pressure suppression chamber 21 are formed in the reactor containment main body vessel 3. The dry well 20 and the pressure suppression chamber 21 are isolated from each other. As will be described later, the region 6 formed inside the dry well head 4 is also a part of the dry well 20 in a state where the dry well head 4 is coupled to the upper end of the reactor containment vessel 3 with a bolt as will be described later. . In the pressure suppression chamber 21, a pressure suppression pool 22 filled with cooling water is formed. A plurality of vent passages (not shown) are formed in the reactor containment main body vessel 3. One end of each of these vent passages opens into the dry well 20, and the other end of each vent passage opens into the cooling water of the pressure suppression pool 22.

  The reactor pressure vessel 1 containing the reactor core is disposed in the dry well 20 in the reactor containment main body vessel 3. The combustible gas treatment device 7 has a recombiner 8 filled with platinum or palladium as a catalyst, a gas supply pipe 9A, and a gas return pipe 9B. The gas supply pipe 9 </ b> A is provided so as to penetrate the reactor containment main body container 3, and communicates the gas inlet of the recombiner 8 with the dry well 20 in the reactor containment main body container 3. The gas return pipe 9B is provided so as to penetrate the reactor containment main body container 3. One end of the gas return pipe 9 </ b> B is connected to the gas outlet of the recombiner 8, and the other end opens into the cooling water of the pressure suppression pool 22. An on-off valve 10A is provided in the gas supply pipe 9A, and an on-off valve 10B is provided in the gas return pipe 9B. A containment vessel vent pipe (gas exhaust pipe) 18 that opens into the dry well 20 is provided through the reactor containment main body vessel 3. An on-off valve 19 is provided in the containment vessel vent pipe 18 outside the reactor containment main body vessel 3. The reactor containment vessel 2 is installed in a reactor building (not shown).

  A hydrogen gas discharge passage (first gas discharge passage) 13 is installed on the inner surface of the dry well head 4. The hydrogen gas discharge passage 13 has a gas inlet 15 disposed at the top of the region 6 in the region 6 inside the dry well head 4 (see FIG. 2). A hydrogen gas discharge passage (second gas discharge passage) 14 is installed on the inner surface of the upper end portion of the reactor containment main body vessel 3. The hydrogen gas discharge passage 14 is connected to a hydrogen gas discharge pipe (gas discharge pipe) 16 having an on-off valve 17 and attached to the outer surface of the reactor containment main body vessel 3. The dry well head 4 and the reactor containment main body vessel 3 are detachably coupled by a flange 5. Specifically, as shown in FIG. 2, the flange 5A provided at the lower end of the dry well head 4 is placed on the flange 5B provided at the upper end of the reactor containment main body vessel 3, and the flange 5A is the flange. Removably attached to 5B with bolts. Before connecting the flange 5A and the flange 5B with bolts, the flange 5A and the flange 5B are circumferentially positioned by a plurality of pins so that the lower end of the hydrogen gas discharge passage 13 is positioned at the upper end of the hydrogen gas discharge passage 14. . For this reason, after the flange 5A and the flange 5B are coupled with a bolt, the hydrogen gas discharge passage 13 and the hydrogen gas discharge passage 14 are separated, but the upper end of the hydrogen gas discharge passage 14 is the lower end of the hydrogen gas discharge passage 13. The hydrogen gas discharge passage 14 communicates with the hydrogen gas discharge passage 13. The hydrogen gas discharge passages 13 and 14 have a shape in which the piping is halved. Each of the hydrogen gas discharge passages 13 and 14 may be a pipe.

  The gas discharge pipe 11 provided with the on-off valves 12A and 12B is connected to the gas supply pipe 9A between the on-off valve 10A and the recombiner 8. A hydrogen gas discharge pipe 16 is connected to the gas discharge pipe 11 between the on-off valve 12A and the on-off valve 12B.

  In this boiling water reactor, for example, a crack that penetrates the main steam pipe connected to the reactor pressure vessel 1 in the reactor containment vessel 2 has occurred, and an accident of loss of coolant, which is an abnormal event, has occurred. Suppose. The high-temperature cooling water in the reactor pressure vessel 1 is discharged into the dry well 20 in the reactor containment vessel 2 as high-temperature steam from a crack in the main steam pipe. The emitted steam contains hydrogen gas and oxygen gas generated by radiolysis of cooling water in the reactor pressure vessel. During operation of the boiling water reactor, nitrogen gas is filled in the reactor containment vessel 2.

  The steam released into the dry well 20 when the coolant loss accident occurs is released into the cooling water of the pressure suppression pool 22 through each vent passage and condensed. For this reason, the pressure rise in the reactor containment vessel 2 when the coolant loss accident occurs can be suppressed.

  When current is supplied from the in-house power supply (or external power supply) at the time of the coolant loss accident, the on-off valves 10A, 10B, 12A and 17 are opened by this current, and a blower (not shown) provided in the gas supply pipe 9A ) Is driven. This blower is installed in the gas supply pipe 9A between the connection point of the gas supply pipe 9A and the gas discharge pipe 11 and the recombiner 8. Nitrogen gas including hydrogen gas and steam in the dry well 20 is supplied to the recombiner 8 through the gas supply pipe 9A by driving the blower. By the action of the catalyst in the recombiner 8, the hydrogen gas is combined with the oxygen gas, and the hydrogen gas is processed. Since hydrogen gas is lighter than nitrogen gas and vapor, it tends to collect in the region 6 in the dry well head 4. The hydrogen gas collected in this region 6 passes from the gas inlet 15 through the hydrogen gas discharge passages 13 and 14, and further flows into the recombiner 8 through the gas discharge pipe 11 and the gas supply pipe 9A. Is processed. The nitrogen gas discharged from the recombiner 8 after the hydrogen gas is processed is released into the cooling water of the pressure suppression pool 22 through the gas return pipe 9B. This nitrogen gas is stored in a wet well (gas layer) formed in the pressure suppression chamber 21 above the liquid level of the cooling water in the pressure suppression pool 22.

  When all power sources are lost when a coolant loss accident occurs, the hydrogen gas concentration in the dry well 20 rises extremely, and it becomes necessary to discharge the hydrogen gas in the dry well 20 to the outside of the reactor building In this case, nitrogen gas containing hydrogen gas in the dry well 20 is released to the outside of the reactor building through the containment vessel vent pipe 18 and further through the hydrogen gas discharge passages 13, 14, the hydrogen gas discharge pipe 16 and the gas discharge pipe 11. Is done. Since all the power sources are lost, for example, by supplying the power generated by the power generator installed in the power supply vehicle to the on-off valves 12B, 17 and 19, the on-off valves 12B, 17 and 19 are opened, and the inside of the dry well 20 Hydrogen gas can be released to the outside. The hydrogen gas accumulated in the region 6 in the dry well head 4 can also be discharged to the outside through the hydrogen gas discharge passages 13, 14, the hydrogen gas discharge pipe 16 and the gas discharge pipe 11 when all the power is lost.

  A radioactive substance removing device is installed downstream of the on-off valve 12B of the gas discharge pipe 11 and downstream of the on-off valve 19 of the containment vessel vent pipe 18, and the inside of the gas exhaust pipe 11 and the containment vessel vent pipe 18 is disposed inside. Each radioactive substance contained in the gas flowing and discharged to the outside is removed by each radioactive substance removing device.

  In this embodiment, a hydrogen gas discharge passage 14 is provided on the inner surface of the reactor containment main body vessel 3, and the hydrogen gas discharge passage 13 that is connected to the hydrogen gas discharge passage 14 and separated from the hydrogen gas discharge passage 14 is used as a dry well. It is installed on the inner surface of the head 4, and the lower end surface of the hydrogen gas discharge passage 13 and the upper end surface of the hydrogen gas discharge passage 14 are only in contact with each other. For this reason, when the bolts connecting the flange 5A and the flange 5B are removed and the dry well head 4 is removed from the reactor containment vessel 3, the hydrogen gas discharge passage 13 integrated with the dry well head 4 is It can be removed from the furnace storage main body container 3. In the removal of the hydrogen gas discharge passage 13, it is not necessary to remove the hydrogen gas discharge passage 13 from the hydrogen gas discharge passage 14, and the dry well head 4 and the hydrogen gas discharge passage 13 can be easily removed from the reactor containment main body container 3. it can.

  Therefore, in the periodical inspection period of the boiling water reactor in which the operation of the boiling water reactor is stopped, the upper lid from which the reactor pressure vessel 1 has been removed is carried out from the reactor containment main body vessel 3, and the reactor The steam dryer and the steam separator installed in the pressure vessel 1 can be started from the reactor pressure vessel 1 and the reactor containment main body vessel 3 earlier, and the fuel assemblies and control rods can be replaced. In addition, the start of various operations in the reactor pressure vessel 1 such as maintenance and inspection of the in-reactor structure installed in the reactor pressure vessel 1 can be accelerated.

  In this embodiment, the gas inlet 15 of the hydrogen gas discharge passage 13 provided on the inner surface of the dry well head 4 is arranged at the top of the region 6 formed inside the dry well 4. For this reason, when an abnormal event such as a coolant loss accident occurs, hydrogen gas accumulated in the region 6 of the dry well 20 above the flange 5B is caused to flow into the hydrogen gas discharge passage 13 from the gas inlet 15. Can be discharged outside the reactor building.

  In this embodiment, not only the hydrogen gas in the reactor containment vessel 2 is discharged through the hydrogen gas discharge passages 13 and 14, the hydrogen gas discharge tube 16 and the gas discharge tube 11, but also the hydrogen gas through the containment vessel vent pipe 18. Since the hydrogen gas in the reactor containment vessel 2 can be discharged earlier to the outside environment even when the entire power supply is lost when an abnormal event occurs, the inside of the reactor containment vessel 2 The risk of hydrogen explosion at can be significantly reduced.

  By disposing the gas inlet 15 in the region 6 in the dry well head 4 above the flange 5A, the hydrogen gas accumulated in the region 6 can be discharged out of the reactor containment vessel 2. By disposing the gas inlet 15 at the top of the region 6 in the region 6, the hydrogen gas accumulated in the region 6 can be efficiently discharged out of the reactor containment vessel 2.

  After the work of replacing the fuel assemblies and control rods and the maintenance and inspection of the reactor internal structure are completed, the steam dryer and the steam separator are carried into the reactor containment main body vessel 3 and the reactor pressure vessel 1 is installed at a predetermined position. Then, the upper lid of the reactor pressure vessel 1 is attached to the reactor pressure vessel 1, and the dry well head 4 is attached to the upper end of the reactor containment main body vessel 3. When the dry well head 4 is attached to the reactor containment main body vessel 3, the hydrogen gas discharge passage 13 is also attached to the reactor containment main body vessel 3. For this reason, the hydrogen gas discharge passage 13 can be easily attached to the reactor containment main body vessel 3. The alignment of the hydrogen gas discharge passage 14 attached to the inner surface of the reactor containment main body vessel 3 of the hydrogen gas discharge passage 13 is easily performed by positioning the flange 5A and the flange 5B with the plurality of pins as described above. be able to.

  A reactor containment vessel according to embodiment 2, which is another embodiment of the present invention, will be described. The reactor containment vessel of the present embodiment is a reactor containment vessel used for a boiling water reactor.

  The reactor containment vessel of the present embodiment is reduced in size by reducing the diameter of the dry well head 4 on the inner surface of the dry well head 4 instead of the hydrogen gas discharge passages 13 and 14 in the reactor containment vessel 2 of the first embodiment. The first inner wall configured as described above is disposed inside the dry well head 4, and the cylindrical second inner wall having an outer diameter smaller than the inner diameter of the cylindrical reactor containment main body container 3 is provided in the reactor containment main body container 3. It has a configuration arranged inside. The cylindrical second inner wall is disposed at the upper end portion of the reactor containment main body vessel 3. Other configurations of the reactor containment vessel of the present embodiment are the same as those of the reactor containment vessel 2 of the first embodiment.

  Due to the arrangement of the first inner wall, the dry well head 4 is doubled. A gap is formed between the inner surface of the dry well head 4 and the outer surface of the first inner wall, and the dry well head 4 and the first inner wall are located within the gap from the top of the outer surface of the first inner wall to the lower end of the first inner wall. The plurality of first ribs arranged radially toward each other are coupled together. In the present embodiment, the region 6 is formed inside the first inner wall. A gas inlet (corresponding to the gas inlet 15 in the first embodiment) that penetrates the first inner wall and communicates with the region 6 is formed at the top of the first inner wall. This gas inlet faces the top of region 6. A space formed between the inner surface of the dry well head 4 and the outer surface of the first inner wall between the first ribs adjacent in the circumferential direction of the dry well head 4 is provided in the region 6 provided in the first embodiment. This corresponds to the hydrogen gas discharge passage 13 for introducing hydrogen gas.

  An annular gap is formed between the inner surface of the reactor containment main body vessel 3 and the outer surface of the cylindrical second inner wall, and the lower end of this gap is attached to the lower ends of the reactor containment main body vessel 3 and the second inner wall. Blocked by an annular plate. A plurality of second ribs extending in the axial direction of the reactor containment main body vessel 3 are arranged in the circumferential direction within the annular gap, and the annular gap is divided into a plurality of regions in the circumferential direction. The reactor containment main body vessel 3 and the second inner wall are joined by these second ribs arranged in the annular gap. Each region formed between the reactor containment main body vessel 3 and the second inner wall between these second ribs corresponds to the hydrogen gas discharge passage 14 provided in the first embodiment for guiding the hydrogen gas in the region 6. To do.

  A through hole is formed in the reactor containment main body 3 that is divided by the plurality of second ribs and communicates with the lower end of each region formed between the reactor containment main body 3 and the second inner wall. A plurality of branch pipes branched from the hydrogen gas discharge pipe 16 on the outside of the reactor containment main body vessel 3 are separately connected to the through holes and attached to the outer surface of the reactor containment main body vessel 3.

  When the flange 5A provided on the dry well head 4 is bolted to the flange 5B provided on the reactor containment main body vessel 3, the dry well head 4 is installed on the reactor containment main body vessel 3. In this state, the lower end surface of the first inner wall is in contact with the upper end surface of the second inner wall, and corresponds to the hydrogen gas discharge passage 13 formed between the first ribs between the dry well head 4 and the first inner wall. The space to be communicated with is an area corresponding to the hydrogen gas discharge passage 14 formed between the second ribs between the reactor containment main body vessel 3 and the second inner wall.

  When a coolant loss accident occurs and vapor and hydrogen gas are released into the dry well 20, nitrogen gas containing hydrogen gas and vapor existing in the region 6 is interposed between the dry well head 4 and the first inner wall. It flows into the hydrogen gas discharge pipe 16 through the formed gap and the gap formed between the reactor containment main body vessel 3 and the second inner wall. When no total power loss has occurred, the nitrogen gas that has flowed into the hydrogen gas discharge pipe 16 is led to the recombiner 8 to process the hydrogen. When all the power is lost, nitrogen gas containing hydrogen gas and the like flowing into the hydrogen gas discharge pipe 16 is released through the gas discharge pipe 11 to the outside of the reactor building.

  In the present embodiment, each effect produced in the first embodiment can be obtained. In this embodiment, since the first inner wall is attached to the dry well head 4 by the first rib, the dry well head 4 is reinforced by the first rib, and the strength of the dry well head 43 against the internal and external pressure is improved. In addition, since the first inner wall is disposed with a gap formed inside the dry well head 4, when a high-temperature vapor is released into the dry well 20 due to an abnormal event such as a coolant loss accident. The gap acts as a buffer against a rapid temperature rise and a pressure of the jetted steam, and the dry well head 4 can be prevented from being damaged.

  A reactor containment vessel according to embodiment 3, which is another embodiment of the present invention, will be described with reference to FIG. The reactor containment vessel of the present embodiment is a reactor containment vessel used for a boiling water reactor.

  The reactor containment vessel of the present embodiment is the same as the reactor containment vessel 2 of the first embodiment except that the hydrogen gas discharge pipe 16 is deleted and the hydrogen gas discharge passage 14 installed on the inner surface of the reactor containment main body vessel 3 is replaced with hydrogen gas. It has a configuration that communicates with the containment vessel vent pipe 18 instead of the discharge pipe 16. Other configurations of the reactor containment vessel of the present embodiment are the same as those of the reactor containment vessel 1 of the first embodiment.

  The configuration of the dry well head 4 used in the reactor containment vessel 2 of the present embodiment is the same as the configuration of the dry well head 4 used in the reactor containment vessel 2 of the first embodiment. A hydrogen gas discharge pipe 14 </ b> A is installed on the inner surface of the upper end portion of the reactor containment main body container 3. The hydrogen gas discharge pipe 14A penetrates the reactor containment main body vessel 3 and is connected to the containment vessel vent pipe 18 shown in FIG. The hydrogen gas discharge pipe 14A is welded to the reactor containment main body container 3 at the through-hole portion of the hydrogen gas discharge pipe 14A in the reactor containment main body container 3, and the hermeticity of the reactor containment main body container 3 is maintained.

  When the flange 5A is coupled to the flange 5B with a bolt and the drywell head 4 is attached to the reactor containment vessel 3, the lower end surface of the hydrogen gas discharge passage 13 comes into contact with the upper end surface of the hydrogen gas discharge pipe 14A. The gas discharge passage 13 communicates with the hydrogen gas discharge pipe 14A.

  When an abnormal event such as a loss of coolant accident occurs and the total power loss occurs, the vapor containing hydrogen gas released from the reactor pressure vessel 1 into the dry well 20 and existing in the region 6 is nitrogen. Together with the gas, it is discharged to the outside of the reactor building through the hydrogen gas discharge passage 13, the hydrogen gas discharge pipe 14A, and the containment vessel vent pipe 18.

  In the present embodiment, each effect produced in the first embodiment can be obtained.

  A reactor containment vessel according to embodiment 4, which is another embodiment of the present invention, will be described with reference to FIG. The reactor containment vessel of the present embodiment is a reactor containment vessel used for a boiling water reactor.

  The reactor containment vessel 2A of the present embodiment is similar to the reactor containment vessel 2 of the first embodiment in that the hydrogen gas discharge passage 13 is installed on the outer surface of the dry well head 4 and the hydrogen gas discharge passage 14 is connected to the reactor containment main body vessel 3. It has the structure installed in the outer surface. Other configurations of the reactor containment vessel 2A of the present embodiment are the same as those of the reactor containment vessel 2 of the first embodiment.

  The dry well head 4A used in the reactor containment vessel 2A of the present embodiment has a hydrogen gas discharge passage 13A provided on the outer surface of the dry well head 4A, and a gas inlet 15A communicating with the hydrogen gas discharge passage 13A is provided in the dry well head 4A. The top of the well head 4A is formed to penetrate the dry well head 4A. The gas inlet 15A faces the top of the region 6 and connects the region 6 and the hydrogen gas discharge passage 13A. The lower end portion of the hydrogen gas discharge passage 13A passes through the flange 5A, and the lower end surface of the hydrogen gas discharge passage 13A is located on the lower surface of the flange 5A.

  A hydrogen gas discharge passage 14 </ b> A is installed on the outer surface of the reactor containment main body container 3 at the upper end of the reactor containment main body container 3. The upper end portion of the hydrogen gas discharge passage 14A passes through the flange 5B, and the upper end surface of the hydrogen gas discharge passage 14A is located on the upper surface of the flange 5B. A hydrogen gas discharge pipe 16 is connected to the lower end of the hydrogen gas discharge passage 14A.

  When an abnormal event such as a coolant loss accident has occurred and no loss of all power has occurred, or when an abnormal event such as a coolant loss accident has occurred and a loss of all power has occurred, the dry well head 4A Nitrogen gas containing hydrogen gas and steam existing in the region 6 flows into the hydrogen gas discharge passage 13A from the gas inlet 15A, and is further introduced into the hydrogen gas discharge pipe 16 through the hydrogen gas discharge passage 14A. When no total power loss has occurred, the nitrogen gas that has flowed into the hydrogen gas discharge pipe 16 is led to the recombiner 8 to process the hydrogen. When all the power is lost, nitrogen gas containing hydrogen gas and the like flowing into the hydrogen gas discharge pipe 16 is released through the gas discharge pipe 11 to the outside of the reactor building.

  In the present embodiment, each effect produced in the first embodiment can be obtained. The present embodiment can also be applied to a boiling water reactor where it is difficult to install the hydrogen gas discharge passage 13 inside the dry well head 4.

  Each of Examples 1 to 4 can be applied to a reactor containment vessel of a pressurized water reactor.

  DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2, 2A ... Reactor containment vessel, 3 ... Reactor containment main body vessel, 4, 4A ... Drywell head, 6 ... Area, 8 ... Recombiner, 9A ... Gas supply pipe, 9B ... Gas return pipe, 11 ... Gas discharge pipe, 13, 13A, 14, 14A ... Hydrogen gas discharge passage, 15, 15A ... Gas inlet, 16 ... Hydrogen gas discharge pipe, 18 ... Containment vessel vent pipe, 20 ... Dry well, 21 ... Pressure suppression chamber.

Claims (6)

A reactor containment vessel surrounding the reactor pressure vessel, and a dry well head removably attached to an upper end of the reactor containment vessel,
A first gas discharge passage is provided in the dry well head, and a gas inlet of the first gas discharge passage is connected to a region in the dry well head, and is separated from the first gas discharge passage. When a passage is provided in the reactor containment main body vessel and the dry well head is attached to the reactor containment main body vessel, the upper end of the second gas discharge passage faces the lower end of the first gas discharge passage. The second gas discharge passage is connected to the first gas discharge passage, and a gas discharge pipe disposed outside the reactor containment main body vessel is connected to the second gas discharge passage. Reactor containment vessel.   The reactor containment vessel according to claim 1, wherein the gas inlet is located on top of the region in the dry well head.   3. The reactor containment vessel according to claim 1, wherein the first gas discharge passage is provided on an inner surface of the dry well head, and the second gas discharge passage is provided on an inner surface of the reactor containment main body vessel.   The first gas discharge passage is provided on an outer surface of the dry well head, the gas inlet is formed in the dry well head, and the second gas discharge passage is provided on an outer surface of the reactor containment main body vessel. Item 3. The reactor containment vessel according to item 1 or 2.   The reactor containment vessel according to any one of claims 1 to 4, wherein the gas discharge pipe is a containment vessel vent pipe.   The reactor containment vessel according to any one of claims 1 to 4, wherein a combustible gas treatment device is communicated with the reactor containment main body vessel, and the gas discharge pipe is connected to the combustible gas treatment device.

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