JP2018072015A - Reactor container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor container having a device capable of replacing the function of a vacuum breaker with high reliability over a long period of time.SOLUTION: A reactor container includes: a dry well (D/W) 5 provided with a reactor pressure container 3; a wet well (W/W) 6 having a suppression pool 7 inside thereof; a vent pipe 8 provided inside the W/W6 and vertically extending and whose upper part thereof opened to the D/W 5; a horizontal vent pipe 81 whose one end is connected to a vent pipe 8 and whose other end opened into the water of the suppression pool 7; a sealed water holding container 11 having an opening part for communicating with a gas-phase part of the W/W 6; a sealed water pipe 12 vertically extending whose upper end is connected to a lower end of the sealed water holding container 11; and a water storage part 13 accumulating the water whose inner part communicates with the D/W5 and whose lower end of the sealed water pipe 12 is opened into the water. A difference Ht in height between the lower end of the sealed water holding container 11 and the low end of the sealed water pipe 12 is larger than a difference Hv in height between a maximum water surface 71 of the suppression pool 7 and the upper end of the horizontal vent pipe 81.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reactor containment vessel used in a nuclear power plant.

  In a nuclear power plant, decay heat is generated in the core even after the reactor is shut down, and steam (steam) is generated by the heat. In a boiling water light water reactor (hereinafter referred to as “BWR”), a reactor pressure vessel (hereinafter referred to as “RPV”) in which the core is stored is located inside the reactor containment vessel (hereinafter referred to as “PCV”). Is installed. PCV is a dry well (hereinafter referred to as “D / W”) in which RPV and main piping are installed, and a wet well having a suppression pool (hereinafter referred to as “S / P”) inside. (Hereinafter referred to as “W / W”). D / W and W / W are connected by a pipe called a vent pipe. The vent pipe has an upper part opened to D / W and a lower part opened to S / P.

  A pipe breakage accident (generally known as “LOCA”) occurs in a nuclear reactor, and steam generated inside the nuclear reactor is released into the PCV. Since the pressure of D / W becomes higher than the pressure of W / W, the discharged steam is driven by the pressure difference between D / W and W / W as a driving force. Then, it flows into the S / P in the W / W and is cooled (condensed) by the S / P. In addition, as a system with a cooling function similar to a vent pipe, the pressure difference between D / W and W / W is used as the driving force, and the gas containing the steam in D / W is cooled through a heat exchanger to become W / W. A static containment cooling system for discharging (hereinafter referred to as “PCCS”, sometimes referred to as “PCC”) has also been proposed. By having such a mechanism, BWR efficiently removes (condenses) vapor generated by decay heat even with a relatively small PCV, and moderates the rise in PCV pressure to suppress excessive pressure rise. Can do.

  On the other hand, depending on the progress of the event, the W / W pressure may temporarily become higher than the D / W pressure. In this case, the steam does not flow from D / W to W / W. For such a case, a vacuum break valve (sometimes called “vacuum breaker”) is installed between W / W and D / W, and the pressure of W / W is the pressure of D / W. When it becomes higher, the W / W pressure can be lowered by releasing the gas inside the W / W to the D / W.

  Regarding the above functions, for example, in documents such as Japanese Patent Laid-Open Nos. 4-301795, 7-72280, 9-166687, and 2009-145342, the vacuum breaker valve is opened. When a phenomenon occurs in which the product adheres in a locked state and does not close (hereinafter, this phenomenon is referred to as “open sticking”, and the occurrence of open sticking is referred to as “open sticking”) or the vacuum breaker valve leaks. Furthermore, it has been pointed out that the PCV cannot be sufficiently cooled, and as a result, the PCV pressure may increase. In these documents, in order to avoid this problem, the vacuum breaker valve is replaced with a sealing function using water head pressure or a structure in which the sealing function is multiplexed (Japanese Patent Laid-Open Nos. HEI 4-301795 and JP 2009-2009). 145342), a structure for dividing the W / W gas phase part (Japanese Patent Laid-Open No. 9-166687), and a structure for increasing the cooling function by covering the inner wall surface of the W / W with a solid material having a large heat capacity (special feature). Measures such as Kaihei 7-72280 have been proposed.

Japanese Patent Laid-Open No. 4-301795 JP-A-7-72280 JP-A-9-166687 JP 2009-145342 A

  As described above, if the vacuum breaker valve is stuck open or leaked, the PCV cannot be cooled sufficiently. In the invention described in Japanese Patent Laid-Open No. 7-72280, the cooling function of PCV is increased by a solid material having a large heat capacity. In general, water is a very excellent refrigerant in terms of cost and heat capacity. Replacing the heat removal function by using a solid material may be costly. In the invention described in Japanese Patent Application Laid-Open No. 9-166687, even if the W / W gas phase part is divided and the vacuum break valve is opened and fixed in some gas phase parts, the W / W Maintaining the function. However, only the function of PCCS is maintained in the present invention, and the water of S / P moves from the W / W part where the vacuum breaker valve is open and fixed to the W / W part where the vacuum breaker valve is healthy, Since the water head pressure applied to the vent pipe increases, the function of the vent pipe installed in the normal BWR cannot be maintained. In Japanese Patent Laid-Open Nos. 4-301795 and 2009-145342, the function of the vacuum breaker valve is replaced or multiplexed by a sealing function using water head pressure. Although this configuration is considered to be effective, when the D / W pressure rises suddenly, the water used for sealing may flow to W / W. After that, the sealing function is maintained. It may not be possible.

  In view of the above problems, an object of the present invention is to provide a reactor containment vessel equipped with a device that can replace the function of a vacuum breaker valve with high reliability over a long period of time.

  A reactor containment vessel according to the present invention includes a dry well in which a reactor pressure vessel for storing a reactor core is installed, a wet well having a suppression pool in which water is stored, and a wet well in the wet well. A vent pipe that extends in the vertical direction and opens at the top to the dry well; and a horizontal vent pipe that extends in the horizontal direction and has one end connected to the vent pipe and the other end opened to the water of the suppression pool. A sealed water holding container provided with an opening for communicating with the gas phase part of the wet well at the top, a sealed water pipe extending at least in the vertical direction and having an upper end connected to the lower end of the sealed water holding container, A water storage section in which water is accumulated, the inside communicates with the dry well, and the lower end of the sealed pipe is open in water. The difference in height Ht between the lower end of the sealed water holding container and the lower end of the sealed water pipe is the difference in height Hv between the highest water surface of the suppression pool and the upper end of the horizontal vent pipe during normal operation of the nuclear reactor. Bigger than.

  ADVANTAGE OF THE INVENTION According to this invention, the reactor containment vessel provided with the apparatus which can substitute the function of a vacuum breaker valve with high reliability over a long period of time can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the reactor containment vessel by Example 1 of this invention. The figure which shows the structural example of the conventional nuclear reactor containment vessel. The figure which shows the 1st modification of a structure of the nuclear reactor containment vessel by Example 1 of this invention. The figure which shows the 1st modification of the structure of the reactor containment vessel by Example 1 of this invention (The point which is not provided with a W / W connection pipe differs from FIG. 5A). The figure which shows the 2nd modification of a structure of the nuclear reactor containment vessel by Example 1 of this invention. The block diagram of the nuclear reactor containment vessel by Example 2 of this invention. The block diagram of the reactor containment vessel by Example 2 of this invention (a sealed water container differs from FIG. 5A). The figure which shows the 1st modification of a structure of the nuclear reactor containment vessel by Example 2 of this invention. The figure which shows the 2nd modification of a structure of the nuclear reactor containment vessel by Example 2 of this invention. The figure which shows the 3rd modification of a structure of the nuclear reactor containment vessel by Example 2 of this invention. The block diagram of the reactor containment vessel by Example 3 of this invention.

  In order to avoid excessive PCV cooling failure and pressure increase that occur due to the vacuum break valve being stuck open, the inventors have to replace the function of the vacuum break valve with a device using sealed water, and In order to operate this apparatus with high reliability over a long period of time, a new finding was found that a sealed water holding container should be installed on the upper part of this apparatus.

  The reactor containment vessel according to the present invention includes at least a sealed water holding vessel communicating with the W / W gas phase portion, a sealed water pipe connected to a lower end of the sealed water holding vessel and extending vertically downward from the sealed water holding vessel, A device is provided that includes a sealed pool (water storage unit) that stores water and has a lower end of the sealed water pipe that is open in water and the inside communicates with the D / W. During normal operation of the nuclear reactor, the height difference Ht between the lower end of the sealed water holding container and the lower end of the sealed water pipe is the maximum water surface of the S / P of W / W and the opening in the S / P of the vent pipe. It is larger than the height difference Hv from the upper end. Even if the above-mentioned apparatus is used for a long period of time, there is a low possibility that a phenomenon of losing the function of the valve, such as the open fixing of the vacuum breaking valve, will occur. The PCV according to the present invention can replace the function of the vacuum breaker valve with high reliability over a long period of time by the above-described apparatus, and can avoid excessive cooling failure of the PCV and an increase in pressure.

  The sealed water pool is installed in the lower part of the D / W, and a sump pit that collects and drains the water in the D / W may be used. A container communicating with / W may be used.

  The sealed water holding container is connected to the D / W side of the vacuum breaker valve installed between W / W and D / W, and communicates with the gas phase part of the W / W through the vacuum breaker valve. You may do it.

  Here, the conventional PCV will be described.

  FIG. 2 is a diagram illustrating a configuration example of a conventional PCV. FIG. 2 shows a PCV of an improved BWR (hereinafter referred to as “ABWR”) as an example. In PCV1, RPV3 which stores the core 2 of a nuclear reactor is installed. A main steam pipe 4 that sends steam generated in the RPV 3 to a turbine (not shown) is connected to the RPV 3. The main steam pipe 4 passes through an area called D / W 5 in the PCV 1. There is also an area called W / W6 in PCV1. W / W6 includes an area (pool) for storing water called S / P7 and a gas phase portion above the water surface 71 of S / P7. In addition, nitrogen gas usually exists in PCV1 of ABWR (air is substituted with nitrogen gas).

  Inside W / W6, a pipe called a vent pipe 8 extending in the vertical direction is installed. The upper part of the vent pipe 8 is open to D / W5, and a horizontal vent pipe 81 is connected to the lower part (below the water surface 71 of S / P7). The horizontal vent pipe 81 is usually installed in a plurality of stages in the vertical direction, one end is connected to the vent pipe 8, extends in the horizontal direction, and the other end opens into the water of S / P7.

  D / W5 is divided according to location, and the part of D / W5 above W / W6 is called the upper D / W51, and the part of D / W5 that includes the lower part of RPV3 next to W / W6 May be referred to as the lower D / W 52.

  Between W / W6 and D / W5, a plurality of vacuum break valves 9 that connect the vapor phase portion of W / W6 and D / W5 are installed. The role of the vacuum break valve 9 will be described below.

  Consider an event in which, for example, a pipe breaks at D / W 5 in PCV1 and steam is released from within RPV3. The pressure of D / W5 increases due to the release of the vapor. When the pressure of D / W5 becomes higher than the pressure of W / W6, the water level in the vent pipe 8 is pushed down. When the water level in the vent pipe 8 is lowered to the position of the horizontal vent pipe 81, the gas (mainly a mixed gas of nitrogen and steam) in the D / W 5 is released into the water of S / P7 through the horizontal vent pipe 81. Then cooled and condensed. In this way, an increase in the pressure of D / W5 is suppressed.

  However, depending on the progress of the event, the W / W6 pressure may be higher than the D / W5 pressure. For example, a D / W spray (not shown) is installed in the D / W 5 and water may be sprayed from the D / W spray to lower the temperature in the PCV 1. In this case, the vapor | steam in D / W5 condenses with spray water, and the pressure of D / W5 reduces. If a large pressure difference is generated between D / W5 and W / W6, a load is applied to the structural material of PCV1, so it is necessary to discharge the gas from W / W6 to D / W5 to equalize the pressure. The vacuum break valve 9 operates in such a situation and opens when the pressure of W / W6 becomes higher than the pressure of D / W5, and functions to release the gas in W / W6 to D / W5. .

  Thereafter, when the pressure of D / W5 becomes higher than the pressure of W / W6, the vacuum breaker valve 9 is automatically closed. This is because if the vacuum break valve 9 is kept open, the gas containing the vapor in the D / W 5 flows into the gas phase portion of the W / W 6 through the vacuum break valve 9 and flows into the S / P 7 water through the vent pipe 8. This is because the steam is not released and the steam is not cooled (condensed) in the S / P 7. For this reason, when open fixation or leakage occurs in the vacuum breaker valve 9, the PCV1 cannot be sufficiently cooled, and the pressure of the PCV1 may increase.

  The reactor containment vessel according to the present invention includes a device that can replace the function of the vacuum break valve 9 and has low possibility of open fixation and leakage. Hereinafter, a reactor containment vessel according to an embodiment of the present invention will be described with reference to the drawings. Note that in the drawings used in this specification, the same or corresponding elements are denoted by the same reference numerals, and repeated description of these elements may be omitted.

  FIG. 1 is a configuration diagram of a PCV according to Embodiment 1 of the present invention. The PCV 1 according to this embodiment has substantially the same configuration as the conventional PCV 1 shown in FIG. 2, but does not include the vacuum break valve 9 that connects the gas phase portion of W / W 6 and D / W 5. PCV1 by a present Example is an apparatus provided with the sump pit 13 which is a W / W connection pipe 10, the sealing water holding container 11, the sealing water pipe 12, and the sealing water pool (water storage part) instead of the vacuum breaker valve 9. (Vacuum break valve replacement device)

  The W / W connecting pipe 10 is a tubular member having one end opened to the gas phase portion of W / W 6 and the other end connected to the sealed water holding container 11.

  The sealed water holding container 11 has an opening in the upper part, and the W / W connecting pipe 10 is connected to the opening, and the lower end is connected to the sealed pipe 12. The sealed water holding container 11 has a horizontal internal cross-sectional area (internal space cross-sectional area) larger than the horizontal internal cross-sectional area of the sealed water pipe 12, and a W / W gas phase of W / W 6 by the W / W connecting pipe 10. It communicates with the department.

  The sealed water pipe 12 extends in the vertical direction, the upper end is connected to the lower end of the sealed water holding container 11, and the lower end is opened in the water of the sump pit 13 installed inside the D / W 5.

  The sump pit 13 is installed on the floor surface of the lower D / W 52, and is a facility for collecting and draining water droplets generated in the D / W 5, where water is accumulated, and it exceeds a certain level even during normal operation of the nuclear reactor. The water level is maintained. The sump pit 13 is open at the top and communicates with the D / W 5 inside.

  The operation principle of the vacuum break valve replacement device provided in the PCV 1 according to this embodiment will be described below.

  First, the operation of the vacuum breaker valve alternative device when the pressure of W / W6 becomes higher than the pressure of D / W5 (when the vacuum breaker valve 9 opens in the conventional PCV1 shown in FIG. 2) will be described. When the pressure of W / W6 becomes higher than the pressure of D / W5, the gas accumulated in the gas phase part of W / W6 (mainly the mixed gas of nitrogen and steam) is the pressure difference between W / W6 and D / W5. By this, it flows through the W / W connection pipe 10, the sealed water holding container 11, and the sealed water pipe 12 in this order. A water surface is formed in the sealed water pipe 12 at substantially the same position as the water surface of the sump pit 13 during normal operation of the nuclear reactor. When the water surface inside the sealed water pipe 12 is pushed down by the gas flowing inside the sealed water pipe 12 and reaches the lower end of the sealed water pipe 12, the gas inside the sealed water pipe 12 is released from the lower end of the sealed water pipe 12 to the sump pit 13. The As a result, gas is discharged from W / W6 to D / W5, and the same function as the vacuum break valve 9 opens in the conventional PCV1 can be realized by the vacuum break valve replacement device of PCV1 of this embodiment. .

  Next, the operation of the vacuum break valve replacement device when the pressure of D / W5 becomes higher than the pressure of W / W6 will be described. When the pressure of D / W5 increases, the water inside the sump pit 13 is pushed down, and the pushed-down water rises inside the sealed water pipe 12. When the water level inside the sealed water pipe 12 rises, a force that pushes down the water in the sealed water pipe 12 works due to the weight of the water in the sealed water pipe 12, and this force (water head) becomes the pressure of D / W5 and W The water surface inside the sealed pipe 12 is stabilized at a position balanced with the difference in pressure of / W6. If the amount of water in the sump pit 13 above the lower end of the sealed water pipe 12 is sufficiently large relative to the amount of water accumulated in the sealed water pipe 12, the water level in the sump pit 13 will not drop to the lower end of the sealed water pipe 12, The D / W5 gas does not pass through the sealed water pipe 12 and flow into the W / W6 gas phase.

  Under the condition that the pressure of D / W5 is higher than the pressure of W / W6 as described above, the gas of D / W5 passes through the vent pipe 8 and the horizontal vent pipe 81, and the water in S / P7 inside W / W6. It is preferable to flow in. For this reason, the vertical length of the sealed water pipe 12 (the difference in height between the lower end of the sealed water holding container 11 and the lower end of the sealed water pipe 12) Ht is the vertical distance between the water surface 71 of the S / P 7 and the horizontal vent pipe 81. It is necessary to make it larger than the direction distance (height difference) Hv. Here, Hv is the maximum water level of S / P7 during normal operation of the reactor (the water level when the water level reaches the upper limit of the management range) 71 and the uppermost horizontal vent pipe 81 (the water level 71 of S / P7). It is defined as the difference in height from the upper end of the nearest horizontal vent pipe 81). If Ht> Hv, the gas of D / W5 does not flow into the gas phase portion of W / W6 through the sealing pipe 12, but flows into the water of S / P7 of W / W6 through the vent pipe 8. .

  It should be noted that the function of preventing the D / W5 gas from flowing into the gas phase of W / W6 by the power of the water in the pipe (water head) It must be maintained continuously until convergence. For example, when an event occurs in which a pipe breaks in the nuclear reactor and steam is released from inside RPV3, the pressure of D / W5 temporarily increases rapidly and exceeds the pressure of W / W6. Can also be very high. In such a case, the water surface inside the sump pit 13 may be pushed down suddenly, and the water surface inside the sealed water pipe 12 may rise suddenly.

  If the sealed water holding container 11 is not provided and the sealed water pipe 12 is directly open to the gas phase portion of W / W6, the pressure difference between D / W5 and W / W6 is caused by the water surface inside the sealed water pipe 12 being the sealed water pipe. If the force (water head) due to the weight of the water in the sealed water pipe 12 when reaching the upper end of the water 12 becomes larger than the force (water head), the water in the sealed water pipe 12 flows from the upper end of the sealed water pipe 12 to the gas phase portion of W / W6. There is a concern that sufficient water for sealing the sealed water pipe 12 will be lost. When sufficient water for sealing the sealed water pipe 12 is lost, the gas of D / W5 passes through the inside of the sealed water pipe 12 and flows into the gas phase portion of W / W6. The same phenomenon occurs as when the is stuck open.

  In the present invention, this problem is avoided by installing the sealed water holding container 11 above the sealed water pipe 12. In the configuration according to the present invention, even if the pressure of D / W 5 increases suddenly and the water level in the sealed water pipe 12 suddenly rises at a stretch, the water pushed up in the sealed water pipe 12 remains in the sealed water holding container. 11, spreads in the horizontal direction and accumulates in the sealed water holding container 11, so that the water in the sealed water pipe 12 can be prevented from flowing out to W / W 6. Furthermore, it is possible to prevent the D / W 5 gas from flowing into the W / W 6 gas phase portion through the sealed water pipe 12 with the water accumulated in the sealed water holding container 11. After the temporary increase in the pressure of D / W5 is settled, the water accumulated in the sealed water holding container 11 returns to the sump pit 13 through the sealed water pipe 12, and the water surface in the sump pit 13 is from the lower end of the sealed water pipe 12. Since it is located above, the sealing function of the vacuum break valve replacement device can be maintained.

  The volume of the sealed water holding container 11 (more precisely, the volume below the opening of the upper part of the sealed water holding container 11) is the lower end of the sealed water pipe 12 of the water accumulated in the sump pit 13 during normal operation of the nuclear reactor. More than the upper volume. If the sealed water holding container 11 has such a volume, the water flowing from the sump pit 13 to the sealed water pipe 12 and rising can be stored in the sealed water holding container 11, so that the water in the sump pit 13 flows out to W / W6. Can be prevented.

  In the example shown in FIG. 1, the sump pit 13 is used as a sealed water pool (water storage part) in which the lower end of the sealed water pipe 12 opens. In order to achieve the object of the present invention, the water is sealed in a sealed pool with a certain amount of water (the amount of water that prevents the D / W5 gas from flowing into the gas phase of W / W6 through the sealing pipe 12). The lower end of the water pipe 12 only needs to be opened, and the sealed water pool is not limited to the sump pit 13.

  Further, in the example shown in FIG. 1, an ABWR is shown as PCV1. PCV1 is not limited to that of ABWR, but PCV having D / W5 and W / W6, or a space equivalent to them, that is, a space including a pool (corresponding to W / W6) and other space (D / PCV provided with Equivalent to W5).

  In the example illustrated in FIG. 1, the PCV 1 including only one vacuum break valve replacement device is illustrated, but the PCV 1 may include a plurality of vacuum break valve replacement devices. Further, a valve may be installed in the W / W connecting pipe 10 or the sealed water pipe 12.

  3A and 3B are diagrams showing a first modification of the configuration of the PCV 1 according to the first embodiment of the present invention. The PCV1 shown in FIGS. 3A and 3B is different from the PCV1 shown in FIG. 1 in that the sealed water holding container 11 is provided inside the W / W6. The sealed water pipe 12 extends in the vertical direction and the horizontal direction, passes through the inside of the W / W 6, penetrates the side wall of the W / W 6, and opens at the lower end of the sump pit 13 installed in the D / W 5.

  In the configuration shown in FIG. 3A, the W / W connecting pipe 10 is connected to the sealed water holding container 11, and the inside of the sealed water holding container 11 and the gas phase part of W / W 6 are connected via the W / W connecting pipe 10. Communicate. In the configuration shown in FIG. 3B, the W / W connecting pipe 10 is not connected to the sealed water holding container 11, and the inside of the sealed water holding container 11 and the W / W via the opening 16 provided in the upper part of the sealed water holding container 11. The gas phase part of W6 communicates. The configuration shown in FIG. 3B has the same effect as the configuration shown in FIG. 3A.

  Generally, the space around and below the RPV 3 (lower D / W 52) is not so wide, but the configuration as shown in FIGS. 3A and 3B improves the degree of freedom of the place where the sealed water holding container 11 is installed. To do. Further, even when a very severe accident occurs and the temperature around the RPV 3 becomes very high, the sealed water holding container 11 can be kept at a relatively low temperature. Heating and evaporation can be prevented, and the long-term reliability of the vacuum break valve replacement device can be further improved.

  FIG. 4 is a diagram illustrating a second modification of the configuration of the PCV 1 according to the first embodiment of the present invention. PCV1 shown in FIG. 4 is different from PCV1 shown in FIG. 1 in that a sealed water holding container 11 is provided outside PCV1. In the configuration shown in FIG. 4, a part of the W / W connecting pipe 10, a sealed water holding container 11, and a part of the sealed water pipe 12 are arranged outside the PCV 1. For this reason, these maintenances become easy, and if a gas flow meter is installed in the sealed water pipe 12, it becomes possible to measure the flow direction and flow rate of the gas between W / W6 and D / W5. It is possible to monitor whether the break valve replacement device is operating as expected.

  In the configuration shown in FIG. 4, a part of the sealed water pipe 12 passes through the inside of the W / W 6, but the sealed water pipe 12 may not pass through the inside of the W / W 6. For example, the sealed water pipe 12 may pass through a part that penetrates the W / W 6 such as a concrete part below the floor surface of the W / W 6 or an access tunnel. In addition, when it is necessary to install an isolation valve in the W / W connection pipe 10 or the sealed water pipe 12, an isolation valve (not shown) may be installed in the W / W connection pipe 10 or the sealed water pipe 12.

  5A and 5B are configuration diagrams of the PCV according to the second embodiment of the present invention. The PCV 1 according to the present embodiment is different from the PCV 1 according to the first embodiment in that the sealed water container 14 is used as a sealed water pool (water storage section). The sealed water container 14 is installed inside the D / W 5 and stores water therein, and the internal gas phase portion communicates with the D / W 5 and has a horizontal internal cross-sectional area (internal space). ) Is larger than the cross-sectional area in the horizontal direction of the sealed water pipe 12. The lower end of the sealed water pipe 12 opens in the water in the sealed water container 14. The configuration shown in FIG. 5A and the configuration shown in FIG.

  The amount of water stored in the sealed water container 14 is determined as follows. That is, the inside of the sealed water container 14 is such that the volume of the water inside the sealed water container 14 above the lower end of the sealed water pipe 12 is larger than the volume inside the sealed water pipe 12 (volume of the sealed water pipe 12). Determine the amount of water. When the sealed water container 14 stores such an amount of water, the lower end of the sealed water pipe 12 opens in the water in the sealed water container 14, so that the D / W 5 gas passes through the sealed water pipe 12. Thus, it is possible to prevent the gas from flowing into the gas phase portion of W / W6.

  In the configuration shown in FIG. 5A, the sealed container 14 has an opening above the surface of the water stored inside, and a D / W connecting pipe 15 is connected to the opening, and the gas phase inside is sealed. The D / W connection pipe 15 communicates with the D / W 5. The D / W connection pipe 15 is a tubular member having one end opened to the D / W 5 and the other end connected to the opening of the sealed container 14. The sealed water container 14 may not be connected to the D / W connection pipe 15, and the internal gas phase portion may communicate directly with the D / W 5 from the opening.

  In the configuration shown in FIG. 5B, the sealed water container 14 is open at the top like the sump pit 13, and the internal gas phase portion communicates with the D / W 5.

  The PCV 1 according to this embodiment has an advantage that the installation location of the vacuum break valve replacement device including the sealed water holding container 11 and the sealed water container 14 can be freely selected regardless of the position of the sump pit 13.

  FIG. 6 is a diagram illustrating a first modification of the configuration of the PCV 1 according to the second embodiment of the present invention. PCV1 shown in FIG. 6 has a vacuum break valve alternative device comprising a W / W connecting pipe 10, a sealed water holding container 11, a sealed water pipe 12, a sealed water container 14, and a D / W connecting pipe 15 inside W / W6. It is different from PCV1 shown in FIG. The sealed water container 14 is located in the water of S / P7. One end of the D / W connection pipe 15 that is not connected to the sealed water container 14 opens into the D / W 5. By providing the vacuum break valve replacement device inside the W / W 6, it is possible to reduce the possibility of the vacuum break valve replacement device being damaged by falling objects from above, and the water in the sealed container 14 is surrounded by the surrounding S / P 7. Therefore, the water in the sealed container 14 can be prevented from being heated and evaporated, and the long-term reliability of the vacuum break valve replacement device can be further improved.

  FIG. 7 is a diagram illustrating a second modification of the configuration of the PCV 1 according to the second embodiment of the present invention. The PCV1 shown in FIG. 7 is different from the PCV1 shown in FIG. 5A in that the vacuum break valve replacement device is provided in the upper D / W 51 having a relatively wide space (that is, there are many places where it can be installed). One end of the W / W connecting pipe 10 that is not connected to the sealed water holding container 11 is open to the gas phase portion of W / W6.

  FIG. 8 is a diagram showing a third modification of the configuration of the PCV 1 according to the second embodiment of the present invention. PCV1 shown in FIG. 8 is different from PCV1 shown in FIG. 5A in that a vacuum break valve replacement device is provided outside PCV1. One end of the D / W connection pipe 15 that is not connected to the sealed water container 14 is opened inside the D / W 5, and one end of the W / W connection pipe 10 that is not connected to the sealed water holding container 11 is W / W 6. Open to the gas phase.

  As described above, the PCV 1 according to the present embodiment has an advantage that there are many places where the vacuum break valve replacement device can be installed. In the configuration shown in FIG. 8, when it is necessary to install an isolation valve in the W / W connection pipe 10 or the D / W connection pipe 15, the W / W connection pipe 10 or the D / W connection pipe 15 is isolated. A valve (not shown) may be installed.

  FIG. 9 is a configuration diagram of the PCV according to the third embodiment of the present invention. The PCV 1 according to the present embodiment is different from the PCV 1 according to the first embodiment in that the vacuum break valve 9 is provided between W / W 6 and D / W 5 and the W / W connecting pipe 10 is connected to the vacuum break valve 9. . The vacuum break valve 9 is the same as that provided in the conventional PCV, and connects the gas phase portion of W / W 6 and D / W 5. One end of the W / W connecting pipe 10 that is not connected to the sealed water holding container 11 is connected to the D / W 5 side of the vacuum breaker valve 9. The sealed water holding container 11 is connected to the D / W5 side of the vacuum breaker valve 9 and communicates with the gas phase portion of W / W6 through the vacuum breaker valve 9.

  Although the PCV 1 according to the present embodiment increases the manufacturing and operation costs, the pressure difference between the W / W 6 and the D / W 5 and the gas flow can be reduced by both the vacuum break valve 9 and the vacuum break valve alternative device. Therefore, the function of the vacuum break valve 9 can be ensured with higher reliability over a longer period of time.

  In the present embodiment, the configuration in which the vacuum break valve 9 is provided in the PCV 1 according to the first embodiment is shown. However, the PCV 1 according to the modification of the first embodiment and the PCV 1 according to the modifications of the second and second embodiments. A vacuum breaker valve 9 may be provided. Similarly to the present embodiment, the W / W connecting pipe 10 can be connected to these vacuum break valves 9 as well.

  In addition, this invention is not limited to said Example, A various deformation | transformation is possible. For example, the above-described embodiments are described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to an aspect including all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to delete a part of the configuration of each embodiment or to add or replace another configuration.

  DESCRIPTION OF SYMBOLS 1 ... Reactor containment vessel (PCV), 2 ... Core, 3 ... Reactor pressure vessel (RPV), 4 ... Main steam pipe, 5 ... Dry well (D / W), 6 ... Wet well (W / W), 7 ... Suppression pool (S / P), 8 ... Vent pipe, 9 ... Vacuum break valve, 10 ... W / W connecting pipe, 11 ... Sealed water holding container, 12 ... Sealed water pipe, 13 ... Sump pit, 14 ... Sealed water container 15 ... D / W connecting pipe, 16 ... Opening of sealed water holding container, 51 ... Upper dry well (upper D / W), 52 ... Lower dry well (lower D / W), 71 ... Water surface of suppression pool, 81 ... Horizontal vent pipe.

Claims (9)

A dry well in which a reactor pressure vessel for storing the reactor core is installed; and
A wet well with a suppression pool in which water is stored, and
A vent pipe provided inside the wet well, extending in a vertical direction and having an upper portion opened to the dry well;
A horizontal vent pipe extending in the horizontal direction, having one end connected to the vent pipe and the other end opening into the water of the suppression pool;
A sealed water holding container provided with an opening at the top for communicating with the gas phase part of the wet well;
A sealed pipe extending at least in the vertical direction and having an upper end connected to the lower end of the sealed water holding container;
A water storage section that stores water, the inside communicates with the dry well, and the lower end of the sealed pipe is open in water;
With
The difference in height Ht between the lower end of the sealed water holding container and the lower end of the sealed water pipe is the difference in height Hv between the highest water surface of the suppression pool and the upper end of the horizontal vent pipe during normal operation of the nuclear reactor. Bigger than,
A reactor containment vessel characterized by that. The volume below the opening of the sealed water holding container is equal to or greater than the volume above the lower end of the sealed pipe of water accumulated in the water storage section during normal operation of the nuclear reactor.
The reactor containment vessel according to claim 1. One end is opened to the gas phase portion of the wet well, and the other end is further provided with a wet well connecting pipe connected to the opening of the sealed water holding container,
The sealed water holding container communicates with the gas phase portion of the wet well through the wet well connecting pipe.
The reactor containment vessel according to claim 1. The water reservoir is a sump pit installed on the floor of the dry well,
The reactor containment vessel according to claim 1. The water storage section is a sealed water container that is installed inside the dry well, stores water therein, and an internal gas phase section communicates with the dry well.
The reactor containment vessel according to claim 1. The volume above the lower end of the sealed pipe of the water inside the sealed container is larger than the volume of the sealed pipe,
The reactor containment vessel according to claim 5. Provided inside the wet well with the sealed water holding container and at least a part of the sealed water pipe,
The reactor containment vessel according to claim 1. The sealed water holding container, the sealed water pipe, and the sealed water container are provided inside the wet well,
A dry well connecting pipe having one end opened to the dry well;
The sealed water container has an opening in the upper part, the other end of the dry well connection pipe is connected to the opening, and an internal gas phase part communicates with the dry well through the dry well connection pipe.
The reactor containment vessel according to claim 5. A vacuum break valve that is installed between the wet well and the dry well, and connects the vapor phase portion of the wet well and the dry well;
The one end of the wet well connecting pipe is connected to the dry well side of the vacuum breaker valve,
The nuclear reactor containment vessel according to claim 3.

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