JP6285337B2 - Primary containment vessel - Google Patents

Description

  The present invention relates to a reactor containment vessel.

  The Advanced Boiling Water Reactor (ABWR) is equipped with a suppression chamber for condensing cooling steam discharged from the reactor pressure vessel and steam in the reactor containment vessel as part of the reactor containment vessel. Yes.

  Pool water in the suppression chamber adjusts the pressure of the containment vessel by condensing steam, and stably captures most of the radioactive materials contained in the steam in the pool water, so that the radioactive materials are in the gas phase. Suppress the transition to. As a result, the radioactive material in the vapor is prevented from leaking to the surrounding environment.

  Here, the transfer of the radioactive substance dissolved in the pool water into the gas phase is affected by the pH of the pool water. For example, when the OH radical of pool water increases and the pH rises, the rate of migration of volatile iodine to the gas phase may increase.

  For this reason, in the prior art described in Patent Document 1, the pH is adjusted by injecting a drug into the suppression chamber as a means for suppressing the radioactive substance in the pool water from moving into the gas phase. In this prior art, a chemical | drug | medicine is inject | poured into the pool water in a suppression chamber using the pressure difference of a nuclear reactor containment vessel and a suppression chamber.

  In addition, although the technique which provides a thermal convection acceleration | stimulation board in a pressure suppression pool is known (patent document 2), it does not accelerate | stimulate a thermal convection for equalization of a chemical | medical agent density | concentration.

JP-A-5-223975 JP-A-5-240987

  In the prior art, the pH of the pool water is adjusted by injecting the drug, but since the temperature of the injected drug and the pool water is different, a density difference occurs in the pool water. Due to this difference in density, there is a difference in drug concentration in the pool water. Therefore, in order to adjust the pH of the pool water to 7 or more in the prior art, a large amount of chemicals must be introduced into the pool water, and the efficiency is low.

  In order to reduce the migration rate of radioactive substances to the gas phase with high efficiency, it is necessary to inject the required amount of drug into the pool water and make the concentration of pool water and drug water uniform. Other than natural convection, there is no equipment for concentration uniformity.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a reactor containment vessel that can reduce a difference in chemical concentration in pool water without using a power source.

  In order to solve the above-mentioned problem, in the reactor containment vessel having the suppression chamber according to the present invention, the suppression chamber is provided with a chemical inlet for charging chemical into the pool water in the suppression chamber. Has a heat transfer member for transferring heat between the pool water located in the upper part and the drug water located in the lower part where the drug is dissolved in the pool water, and the heat of the upper pool water is arranged by the heat transfer member. Is transferred to the drug water in the lower part, and thermal convection is caused in the suppression chamber to promote uniform concentration of the drug.

  According to the present invention, in the suppression chamber, heat from the upper pool water is transferred to the lower drug water by the heat transfer member, and heat convection is generated, so that the drug water moves upward and promotes uniform drug concentration. Is done.

Sectional drawing which shows the outline of a nuclear power plant. The top view seen from the arrow II-II direction in FIG. Sectional drawing which expands and shows a part of suppression chamber. An expanded sectional view of a suppression chamber concerning a 2nd example. An expanded sectional view of a suppression chamber concerning a 3rd example. An expanded sectional view of a suppression chamber concerning a 4th example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the concentration distribution that can occur in the pool water is made uniform, and the pH is adjusted with high efficiency. Furthermore, in this embodiment, since the temperature difference which arises also at the time of normal operation can be reduced, the effect which condenses the steam which has moved from the reactor containment vessel is also improved.

  A first embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view schematically showing an improved boiling water light water reactor. The reactor building 1 is provided with a reactor containment vessel 2 formed of reinforced concrete and a steel liner.

  The reactor containment vessel 2 accommodates a reactor pressure vessel 3 formed from steel as a substantially cylindrical structure. On the bottom side of the reactor containment vessel 2, an annular suppression chamber 4 is provided in the torus chamber 1 </ b> A of the reactor building 1. The internal space of the suppression chamber 4 and the internal space of the dry well 2 </ b> A of the reactor containment vessel 2 are connected to each other via a vent pipe 5. The outlet on the distal end side of the vent pipe 5 is opened in the pool water 6 in the suppression chamber 4 so that the furnace steam is discharged into the pool water 6.

  A plurality of spray nozzles 7 are provided on the upper side of the suppression chamber 4 for injecting a predetermined drug for pH adjustment to the pool water. The medicine is sprayed from the spray nozzle 7 toward the pool water 6 and mixed with the pool water 6. The pool water (hereinafter referred to as drug water 8) mixed with the drug is lower in temperature than the pool water 6 of the drug, and therefore has a higher density than the pool water 6. Accordingly, the drug water 8 sinks below the pool water 6 to form a drug water layer.

  FIG. 2 is a plan view seen from the direction of arrow II-II in FIG. 1 with the reactor building 1 removed. As described above, the suppression chamber 4 is formed in an annular shape so as to surround the dry well 2 </ b> A of the reactor containment vessel 2. A plurality of vent pipes 5 are provided at regular intervals in the circumferential direction from the dry well 2A. For example, the eight vent pipes 5 open at the base end side in the dry well 2 </ b> A, and the tip end side extends to the suppression chamber 4 to open into the pool water 6. Therefore, the vapor in the dry well 2A is discharged into the pool water 6 through the vent pipe 5, and is cooled by the pool water 6 and condensed.

  The upper part of the suppression chamber 4 is provided with a spray nozzle 7, which is an example of a “medicine inlet”, spaced apart at equal intervals in the circumferential direction. The spray nozzle 7 is located at the center in the width direction of the suppression chamber 4. The proximal end side of the spray nozzle 7 is connected to a medicine supply device (not shown), and the distal end side of the spray nozzle 7 is attached so as to face the pool water 6. For example, carbonate is used as the drug.

  For example, the spray nozzle 7 may be provided corresponding to the attachment position of each vent pipe 5 to the suppression chamber 4, or may be provided between the vent pipes 5. In this embodiment, spray nozzles 7 are provided at both the attachment position of each vent pipe 5 and the intermediate position of each vent pipe 5.

  The medicine sprayed from the spray nozzle 7 passes through the gas phase part 4 </ b> A in the suppression chamber 4 and reaches the pool water 6, and is mixed with the pool water 6 to become the medicine water 8. Since the temperature of the medicine is lower than that of the pool water 6, the temperature of the medicine water 8 is also lower than the temperature of the pool water 6. The drug water 8 has a high density due to its low temperature, and sinks below the suppression chamber 4. As a result, in the liquid phase portion of the suppression chamber 4, two layers of pool water 6 located on the upper side and drug water 8 located on the lower side are formed as shown in FIG.

  FIG. 3 shows an enlarged cross section of the suppression chamber 4. In the suppression chamber 4, the heat transfer member 10 is erected vertically from the bottom of the suppression chamber 4 toward the water surface of the pool water 6, located immediately below the spray nozzle 7.

  Since the bifurcated outlet 5A of the vent pipe 5 is provided so as to open in the pool water 6, the upper end of the heat transfer member 10 extending to the water surface of the pool water 6 is more than the outlet 5A. Located high. When viewed from the side, the upper side of the heat transfer member 10 is sandwiched between the bifurcated outlet 5 </ b> A of the vent pipe 5.

  The longitudinal axis of the heat transfer member 10 and the axis of the spray nozzle 7 are substantially parallel. In this embodiment, the longitudinal axis of the heat transfer member 10 and the axis of the spray nozzle 7 have a common axis O1-O1 and are arranged substantially coaxially. Furthermore, the common axis O1-O1 of the heat transfer member 10 and the spray nozzle 7 and the axis O2-O2 of the outlet 5A of the vent pipe 5 are substantially parallel. In the present embodiment, the longitudinal axis of the heat transfer member 10, the axis of the spray nozzle 7, and the axis of the outlet 5A of the vent pipe 5 are set to be parallel to each other.

  The heat transfer member 10 is made of a material having a higher thermal conductivity than the pool water 6 and the drug water 8, for example, in a columnar shape, a plate shape, or the like. The heat transfer member 10 preferably has a thermal conductivity of 0.7 W / mK or more, for example. As an example, silver (420 W / mK), copper (370 W / mK), gold (320 W / mK), aluminum (256 W / mK), duralumin (165 W / mK), iron (75 W / mK), stainless steel (15 W) / MK).

  In the present embodiment, as described above, the water is transmitted through the pool water 6 layer formed in the upper portion of the suppression chamber 4 and the drug water 8 layer formed in the lower portion of the suppression chamber 4. The thermal member 10 is erected from the bottom of the suppression chamber 4 upward in the vertical direction. Thereby, the heat which the pool water 6 has is transmitted to the chemical water 8 through the heat transfer member 10, and as a result, as shown by the arrow line in FIG. The rising density decreases and increases toward the pool water 6. Thus, the heat transfer member 10 improves the heat convection in the suppression chamber 4 and promotes the uniform concentration of the drug. However, the present invention is not limited to the above-described configuration, and other configurations may be used as long as heat transfer from the pool water 6 to the drug water 8 can be promoted. For example, the shape and arrangement of the heat transfer member 10 may be changed as appropriate.

  As in this embodiment, a plurality of spray nozzles 7 are arranged at equal intervals in the circumferential direction at the center in the width direction of the suppression chamber 4, and are transmitted vertically from the bottom of the suppression chamber 4 to the water surface of the pool water 6. By disposing the heating member 10 directly below each spray nozzle 7, the drug water 8 that tends to exist below the spray nozzle 7 is warmed by the heat of the pool water 6, and the drug water 8 and the pool water 6 are mixed. In addition, the difference in drug concentration can be reduced.

  If the spray nozzle 7 and the heat transfer member 10 are far apart in the plane direction perpendicular to the vertical line, there is little drug water 8 present near the surface of the heat transfer member 10, and the heat convection of the drug water 8 is also heat transfer. Since it is biased to the vicinity of the member 10, it takes a long time to eliminate the difference in drug concentration. On the other hand, in the present embodiment, the heat transfer member 10 is disposed in the region where the chemical water 8 having a high concentration at a low temperature is generated. Therefore, it is possible to efficiently generate thermal convection and reduce the concentration difference.

  Therefore, according to the present embodiment, if an appropriate amount of medicine is introduced into the suppression chamber 4, the pH of the pool water 6 can be appropriately adjusted, and the efficiency is improved.

  Further, according to the present embodiment, the heat transfer member 10 only needs to be formed of a material having a thermal conductivity of 0.7 W / mK or more, for example, and a heater or a stirring mechanism is unnecessary. Also, the function of the suppression chamber 4 can be maintained.

  A second embodiment will be described with reference to FIG. Each of the following embodiments including this embodiment corresponds to a modification of the first embodiment, and therefore, differences from the first embodiment will be mainly described. In the present embodiment, the heat transfer area is increased by providing a plurality of fins 11 on the heat transfer member 10A.

  FIG. 4 is an enlarged cross-sectional view showing the suppression chamber 4 of the reactor containment vessel 2 according to this embodiment. The heat transfer member 10A of the present embodiment is provided with a plurality of fins 11 as compared to the heat transfer member 10 described in the first embodiment. In the present embodiment, for example, the simple-shaped fins 11 are integrally formed on the entire side surface from the lower end side to the upper end side of the heat transfer member 10A so that the specific surface area becomes 10 times.

  Configuring this embodiment like this also achieves the same operational effects as the first embodiment. Furthermore, in the present embodiment, by providing a plurality of fins 11 on the heat transfer member 10A, the area for transferring the heat of the pool water 6 to the chemical water 8 can be increased, and thus more effectively than the first embodiment, The thermal convection of the drug water 8 can be promoted, and the drug concentration difference can be reduced.

  The structure of the fin 11 is not limited to a simple plate shape, and may be a more complicated shape. By complicating the shape of the fin 11, the surface area is further improved.

  A third embodiment will be described with reference to FIG. In the present embodiment, the heat of the pool water 6 is guided to the bottom of the suppression chamber 4 by providing the heat insulating portion 12 at the intermediate portion in the longitudinal direction of the heat transfer member 10B.

  FIG. 5 is an enlarged sectional view showing the suppression chamber 4 of the reactor containment vessel 2 according to this embodiment. The heat transfer member 10 </ b> B of the present embodiment is provided with a heat insulating portion 12 so as to cover a predetermined region straddling the vicinity of the concentration boundary between the pool water 6 and the chemical water 8. The heat insulating part 12 is formed from a material having a lower heat transfer coefficient than the pool water 6 and the chemical water 8 (for example, less than 0.7 W / mK) in a cylindrical shape or a rectangular tube shape.

  The surface of the heat insulation part 12 and the surface of the area | region in which the heat insulation part 12 is not provided among the heat-transfer members 10B correspond with no level | step difference. That is, the predetermined region of the heat transfer member 10B has a smaller diameter than other portions, and the heat insulating portion 12 is provided so as to fill a portion where the diameter is reduced. Thereby, the heat insulation part 12 can also exhibit the effect which reinforces the location reduced in diameter in addition to the heat insulation effect | action.

  Configuring this embodiment like this also achieves the same operational effects as the first embodiment. Further, in the present embodiment, in the heat transfer member 10B, the heat received from the pool water 6 is released halfway by covering the vicinity of the boundary between the layer of the pool water 6 and the layer of the chemical water 8 with the heat insulating portion 12. And can be guided to the lower side of the heat transfer member 10B. Thereby, in the present Example, the thermal convection of the chemical | medical solution 8 can be generated in the bottom part vicinity of the suppression chamber 4, the distance which the warmed chemical | medical solution 8 rises can be lengthened, and the stirring effect can be improved.

  In addition, the structure of the heat insulation part 12 is not restricted to the example shown in FIG. It is good also as a structure which makes the internal diameter of the heat insulation part 12 correspond to the outer diameter of the cylindrical heat transfer member 10B, and fits the heat insulation part 12 on the outer side of the heat transfer member 10B. Or you may form the heat insulation part 12 by providing the coating material and film with heat insulation in the predetermined area | region of the heat-transfer member 10B.

  A fourth embodiment will be described with reference to FIG. In the present embodiment, the second embodiment and the third embodiment are combined. FIG. 6 is an enlarged sectional view showing the suppression chamber 4 of the reactor containment vessel 2 according to this embodiment.

  The heat transfer member 10 </ b> C of this embodiment includes both the plurality of fins 11 described in the second embodiment and the heat insulating portion 12 described in the third embodiment. Among the side surfaces of the heat transfer member 10C, a heat insulating portion 12 is provided in a predetermined region located near the concentration boundary between the pool water 6 and the chemical water 8, and a plurality of fins 11 are provided on the upper and lower portions other than the predetermined region, respectively. Is provided.

  According to this embodiment configured as described above, the same operational effects as described in the first to third embodiments can be obtained. In the present embodiment, the heat of the pool water 6 is efficiently taken into the heat transfer member 10C by the fins 11 at the upper part, and the heat is prevented from being released during the transportation by the heat insulating portion 12, and the lower part of the heat transfer member 10C It can be guided to the drug water 8 from the lower fin 11. Therefore, the heat of the pool water 6 can be transmitted to the drug water 8 more effectively than in the above embodiments, and heat convection with a long moving distance can be generated, and the drugs can be mixed effectively.

  In addition, this invention is not limited to embodiment mentioned above. A person skilled in the art can make various additions and changes within the scope of the present invention.

  1: Reactor building, 1A: Torus chamber, 2: Reactor containment vessel 2, 2A: Drywell, 3: Reactor pressure vessel, 4: Suppression chamber, 4A: Gas phase section, 5: Vent pipe, 5A: Flow Outlet, 6: Pool water, 7: Spray nozzle, 8: Chemical water, 10, 10A, 10B, 10C: Heat transfer member, 11: Fin, 12: Heat insulation part

Claims (6)

A reactor containment vessel having a suppression chamber,
The suppression chamber is provided with a drug inlet for charging the pool water in the suppression chamber.
In the suppression chamber, a heat transfer member for transferring heat between the pool water located at the upper part and the drug water located at the lower part and the drug dissolved in the pool water is disposed,
The heat of the upper pool water is transferred to the lower drug water by the heat transfer member, and the concentration of the drug is promoted by causing thermal convection in the suppression chamber,
The heat transfer member is formed of a material having a higher heat transfer rate than the pool water and the chemical water, and has at least one fin, and is located below the chemical inlet, and the suppression chamber Erected vertically from the bottom of the
Reactor containment vessel. The heat transfer member has a heat insulating portion located near the boundary between the pool water and the chemical water.
The reactor containment vessel according to claim 1 . The heat insulating part is formed of a material having a lower heat transfer coefficient than the pool water and the chemical water.
The reactor containment vessel according to claim 2 . The drug inlet is provided in the suppression chamber above the outlet of a vent pipe connecting the dry well and the suppression chamber, and the heat transfer member is respectively provided below the drug inlet. Is provided,
The reactor containment vessel according to claim 1 . The medicine input port, has been positioned between the vent pipe between which connects the the de Raiweru suppression chamber provided in the suppression chamber, each of said heat transfer member on the lower side of the tablet putting port provided Being
The reactor containment vessel according to claim 1 . The heat transfer member has a heat insulating portion located near the boundary between the pool water and the chemical water, and fins are provided above and below the heat insulating portion, respectively.
The nuclear reactor containment vessel according to any one of claims 1 to 5 .

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