JP2016109618A - Nuclear reactor heat utilization system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear reactor heat utilization system capable of improving safety as compared with a conventional technique by using minimum heat exchangers.SOLUTION: A first pipe into which part of high-temperature gas refrigerant unloaded from a reactor flows is connected to a primary side of a first heat exchanger 21 and a second pipe is connected to a secondary side thereof. The second pipe 24 is connected to a primary side of a second heat exchanger 22 and a third pipe 26 for heat utilization is connected to a secondary side thereof. First flow-passage control mechanism parts 25, 28, and 33 connect the secondary side of the first heat exchanger 21 to the primary side of the second heat exchanger 22 in a normal case, and disconnect the secondary side of the first heat exchanger 21 from the primary side of the second heat exchanger 22 so as to circulate the refrigerant while bypassing the secondary side of the first heat exchanger 21 in a first predetermined case. First pressure regulation parts 30, 39, and 40 regulate a pressure of the second pipe to be higher than a pressure of the first pipe by a first pressure value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a reactor heat utilization system.

  It has been proposed that a boiling water reactor (BWR) is positioned as one of distributed power sources and constructed near an energy consuming area to effectively use not only power generation but also its heat. In order to effectively use the heat generated in the nuclear reactor, the introduction of a so-called cogeneration system (heat utilization system) that collects the heat of the coolant of the nuclear reactor and uses it as it is has been proposed. Yes.

  By the way, since BWR employs a direct cycle in which steam generated in a nuclear reactor is directly guided to a turbine to generate electric power, the steam generated in the nuclear reactor contains a radioactive substance. Therefore, when using a heat utilization system in the BWR, in order to reduce the potential for the radioactive material to move to the heat utilization side, the fluid containing the radioactive material and the fluid used for heat utilization do not directly exchange heat. Need to be configured.

  For this reason, a technology has been proposed in which an intermediate heat exchanger is provided between the piping system containing the radioactive material and the piping system on the heat utilization side so as to prevent the radioactive material from moving to the heat utilization side of the system. (Patent Document 1).

JP 2001-4791 A

  In the conventional nuclear reactor heat utilization system, by providing an intermediate heat exchanger, the possibility of radioactive substances moving to the heat utilization side is suppressed, but the intermediate heat exchanger may also fail. Therefore, it is conceivable to improve safety by providing a plurality of intermediate heat exchangers. The more intermediate heat exchangers are provided, the lower the possibility that radioactive materials will migrate to the heat utilization side, but on the other hand, not only will the cost increase, but the scope of maintenance work will also be widened and workability will be reduced.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a reactor heat utilization system capable of improving safety as compared with the prior art by using a minimum necessary heat exchanger. There is.

  In order to solve the above-mentioned problem, a reactor heat utilization system according to the present invention is a reactor heat utilization system that utilizes the heat of a reactor, and a first portion into which a part of a high-temperature gas refrigerant taken out from the reactor flows. The piping, the second piping through which the refrigerant circulates, the first piping is connected to the primary side, and the second piping is connected to the secondary side, so that the amount of heat between the first piping and the second piping is reduced. The 1st heat exchanger to exchange, the 3rd piping for heat utilization, the 2nd piping is connected to the primary side, and the 3rd piping is connected to the secondary side, and the 2nd piping and the 3rd piping The second heat exchanger for exchanging the amount of heat between the second heat exchanger and the secondary side of the first heat exchanger and the primary side of the second heat exchanger in the normal case, and the first case in the first predetermined case. A first flow path for separating the secondary side of the heat exchanger from the primary side of the second heat exchanger and bypassing the secondary side of the first heat exchanger to circulate the refrigerant Comprising a control mechanism, a first pressure regulator for adjusting the pressure of the second pipe so than the pressure in the first pipe high as the first pressure value.

  According to the present invention, since the pressure of the second pipe is made higher by the first pressure value than the pressure of the first pipe, even if the heat transfer pipe is damaged or the like in the first heat exchanger, It can suppress that a refrigerant | coolant penetrate | invades into 2 piping side. Further, in the first predetermined case, the secondary side of the first heat exchanger and the primary side of the second heat exchanger are disconnected, and the secondary side of the first heat exchanger is bypassed to circulate the refrigerant. Therefore, it is possible to suppress the refrigerant in the first pipe from flowing into the second heat exchanger.

The whole block diagram which shows the electric power generation system of a boiling water reactor. The block diagram of a reactor heat utilization system. The block diagram of the reactor heat utilization system containing the outline of the heat exchanger tube structure of a heat exchanger. The flowchart which shows the control processing which ensures the safety | security of a nuclear reactor heat utilization system. Configuration explanatory drawing when damage etc. arise in an intermediate heat exchanger. Structure explanatory drawing of the state which isolate | separated the intermediate heat exchanger and the heat exchanger. Structure explanatory drawing when damage etc. arise in a heat exchanger. Structure explanatory drawing of the state which disconnected the piping of the heat utilization system from the heat exchanger.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, as will be described later, the intermediate heat exchanger 21 and the heat exchanger 22 are provided between the pipe 23 connected to the main steam system pipe 3 and the pipe 26 for heat utilization, thereby providing radioactive. The vapor containing the substance and the refrigerant for heat utilization do not directly exchange heat.

  In the present embodiment, since the pressure of the intermediate loop pipe 24 is set higher than that of the main steam system pipe 23, the radioactive material is also connected to the intermediate loop pipe even when the heat transfer pipe of the intermediate heat exchanger 21 is damaged. Intrusion into 24 can be suppressed.

  Further, in the present embodiment, when steam enters the intermediate loop pipe 24 from the main steam system side pipe 23, the intermediate heat exchanger 21 and the heat exchanger 22 are separated from each other, and the secondary heat exchanger 21 has a secondary side. A fluid (for example, compressed water) as a refrigerant is circulated by bypassing the side. Thereby, it can suppress that the fluid which may contain a radioactive substance flows into the heat exchanger 22. FIG.

  Further, in the present embodiment, when the separation of the intermediate heat exchanger 21 fails, the pressure of the heat utilization system pipe 26 is made higher than that of the pipe 24 of the intermediate loop. For this reason, it is possible to suppress a fluid that may contain a radioactive substance from entering the heat utilization system pipe 26 via the heat exchanger 22 from the intermediate loop pipe 24.

  Further, in the present embodiment, when the fluid as the refrigerant from the intermediate loop pipe 24 enters the heat utilization system pipe 26 via the heat exchanger 22, the heat utilization system pipe 26 is disconnected from the heat exchanger 22. The fluid is circulated by bypassing the secondary side of the heat exchanger 22. Thereby, it can suppress that the fluid which may contain a radioactive substance penetrate | invades into the piping 26 of a heat utilization system.

  According to this embodiment configured as described above, a safety device for preventing vapor or fluid containing a radioactive substance from entering the piping 26 of the heat utilization system is provided in a multiple manner, although the configuration is relatively simple. be able to.

  A first embodiment will be described with reference to FIGS. FIG. 1 shows an overall configuration diagram of a nuclear power plant. As will be described later, the nuclear power plant includes a core 1, a reactor vessel 2, a main steam system pipe 3, a high pressure turbine 4, a low pressure turbine 6, a generator 8, a condenser 9, a condensate pump 10, and a supply and condensate system pipe. 11, a feed water pump 12, a feed water heater 13, and a reactor heat utilization system 20.

  A core 1 containing fissile material is accommodated in a reactor vessel 2. A main steam system pipe 3 is connected to the reactor vessel 2. The main steam system pipe 3 sends steam as “high temperature gas refrigerant” flowing out from the reactor vessel 2 to the high pressure turbine 4 and the low pressure turbine 6.

  Steam output from the reactor vessel 2 rotates the shaft 7 via the high-pressure turbine 4 and the low-pressure turbine 6. The generator 8 is driven by the rotation of the shaft 7 to generate power. The steam used for work is sent to the condenser 9. The steam is condensed in the condenser 9 to become water, and flows into the feed and condensate piping 11. Water in the feed water condensate system pipe 11 is pumped to the reactor vessel 2 by the condensate pump 10 and the feed water pump 12. Further, the water in the feed water condensate system pipe 11 is heated by the feed water heater 13 and sent to the reactor vessel 2.

  A moisture separator 5 is provided in the main steam line 3 located between the high-pressure turbine 4 and the low-pressure turbine 6. The extraction piping 15 supplies a part of the steam that has passed through the moisture separator 5 to the feed pump driving turbine 14 and the condenser 9. The extracted steam works in the feed water pump driving turbine 14 and rotates the feed water pump 12. The steam that has finished its work is sent to the condenser 9 and returned to the water. Even in the shaft seal portion of the feed water pump drive turbine 14, steam is sent to the condenser 9 and returned to water in order to prevent leakage from the seal portion to the outside of the casing.

  A system 20 that uses the heat of the nuclear reactor is provided between the main steam system pipe 3 and the feed and condensate system pipe 11. Where the heat utilization system 20 is provided varies depending on the steam temperature to be used and what the heat is used for. In the present embodiment, as an example, the heat utilization system 20 is provided so as to utilize the steam on the outlet side of the high-pressure turbine 4. The heat utilization system 20 may be provided in a place other than that shown in FIG.

  FIG. 2 is a configuration diagram of the nuclear reactor heat utilization system 20. The reactor heat utilization system 20 is provided between the main steam system pipe 3 and the feed and condensate system pipe 11 as described above, and is controlled by the controller 50. The controller 50 and the devices 21 to 43 described later can be collectively referred to as the reactor heat utilization system 20.

  The reactor heat utilization system 20 can be roughly divided into three piping systems. The first pipe 23 is a pipe that branches from the main steam system pipe 3 containing the radioactive substance and merges with the feed and condensate system pipe 11. Steam flows from the first pipe 23 to the intermediate heat exchanger 21, and fluid (saturated water) flows from the outlet of the intermediate heat exchanger 21 to the supply and condensate pipe 11. The second pipe 24 is provided adjacent to the first pipe 23 independently of the first pipe 23, and is a pipe that circulates fluid (compressed water). The second pipe 24 can also be called an intermediate loop pipe. The third pipe 26 is a pipe for heat utilization adjacent to the pipe 24 independently of the intermediate loop pipe 24, and a fluid (compressed water) flows through the third pipe 26.

  An intermediate heat exchanger 21 as a “first heat exchanger” is provided between the first pipe 23 and the second pipe 24 of the intermediate loop. A first pipe 23 is connected to the primary side of the intermediate heat exchanger 21, and an intermediate loop pipe 24 is connected to the secondary side of the intermediate heat exchanger 21. Specifically, the intermediate heat pipe 21 is connected to the intermediate loop pipe 24 that is the secondary side, and the primary pipe 23 that is the primary side is connected around each of the heat transfer pipes. The heat of the first pipe 23 is transferred to the intermediate loop pipe 24 via the intermediate heat exchanger 21.

  A heat exchanger 22 as a “second heat exchanger” is provided between the intermediate loop pipe 24 and the third pipe 26 for heat utilization. An intermediate loop pipe 24 is connected to the primary side of the heat exchanger 22, and a third pipe 26 is connected to the secondary side of the heat exchanger 22. Switching portions 44 and 45 for switching the flow path of the heat transfer tube are provided at the inlet and outlet on the secondary side of the heat exchanger 22. The heat exchanger 22 includes a triple-structure flow path. The structure will be described later with reference to FIG. The heat of the intermediate loop pipe 24 is transferred to the third pipe 26 via the heat exchanger 22.

  The intermediate loop pipe 24 is provided with a first bypass pipe 25 so as to bypass the secondary side of the intermediate heat exchanger 21, and a first gate valve 28 is provided in the middle of the first bypass pipe 25. It has been. The third pipe 26 for heat utilization is provided with a second bypass pipe 27 so as to bypass the secondary side of the heat exchanger 22, and the second bypass pipe 27 has a second gate valve 29. Is provided. Normally, the gate valves 28 and 29 are closed and the bypass pipes 25 and 27 are shut off. When the controller 50 outputs a control signal in a predetermined case, the gate valves 28 and 29 are opened. When the gate valves 28 and 29 are opened, the bypass pipes 25 and 27 communicate with each other.

  Each pipe 23, 24, 26 is provided with globe valves 32, 33, 34 for adjusting the pressure and flow rate. Each of the globe valves 32 to 34 adjusts the flow rate of the fluid by changing the opening area according to a control signal from the controller 50. As the opening area changes, the pressure (differential pressure) between the inlet and outlet of the globe valve changes, and the flow rate of the fluid passing through the globe valve changes with this pressure change. In addition, not only a globe valve but the valve structure which can implement | achieve the same function can be used. In the figure, the valve in the open state is shown in white, and the valve in the closed state is shown in black.

  The first globe valve 32 is located on the downstream side of the intermediate heat exchanger 21 and is provided in the middle of the first pipe 23. The second globe valve 33 is located between the first bypass pipe 25 and the heat exchanger 22 and is provided in the middle of the intermediate loop pipe 24. The third globe valve 34 is located between the second bypass pipe 27 and the heat utilization side device (not shown), and is provided in the middle of the third pipe 26. An outflow pipe 26A and an inflow pipe 26B are connected to the third pipe 26, and a fluid (for example, a liquid refrigerant such as compressed water) flowing in from the inflow pipe 26B is subjected to heat exchange in the heat exchanger 22 and then outflowed. It is supplied to heat utilization equipment outside the figure via the pipe 26A. The third globe valve 34 is provided in the middle of the outflow pipe 26 </ b> A of the third pipe 26.

  The intermediate loop pipe 24 is provided with a pump 35 and a check valve 37 located between the secondary inlet of the intermediate heat exchanger 21 and the primary outlet of the heat exchanger 22. Yes. The pump 35 circulates the fluid in the pipe 24 of the intermediate loop. The check valve 37 allows the flow from the outlet on the primary side of the heat exchanger 22 and blocks the reverse flow.

  The third pipe 26 for heat utilization is provided with a pump 36 and a check valve 38 located between the secondary side inlet of the heat exchanger 22 and the inflow pipe 26B. The pump 36 is for sending fluid into the heat exchanger 22. The check valve 38 allows a flow from the heat utilization device to the heat exchanger 22 and prevents a reverse flow.

  The first bypass pipe 25, the first gate valve 28, and the second globe valve 33 constitute a “first flow path control mechanism”. As will be described later, the first flow path control mechanism unit normally connects the secondary side of the intermediate heat exchanger 21 and the primary side of the heat exchanger 22. In the first predetermined case, the first flow path control mechanism section separates the secondary side of the intermediate heat exchanger 21 from the primary side of the heat exchanger 22 and sets the secondary side of the intermediate heat exchanger 21 to the first side. The refrigerant is circulated by bypassing the bypass pipe 25.

  The “second flow path control mechanism unit” includes a second bypass pipe 27, a second gate valve 29, and a third globe valve 34. The second flow path control mechanism unit connects the secondary side of the heat exchanger 22 and the third pipe 26 in a normal case. The second flow path control mechanism separates the secondary side of the heat exchanger 22 and the third pipe 26 in the third predetermined case, and bypasses the secondary side of the heat exchanger 22 with the second bypass pipe 27. Circulate the fluid. That is, in the third predetermined case, the fluid flow between the heat exchanger 22 and the heat utilization device (not shown) is blocked.

  In this example, even if the heat transfer tube in the heat exchanger is damaged, the pressure inside the heat transfer tube is set to be higher than the pressure outside the heat transfer tube so that the fluid flowing outside the heat transfer tube does not enter the heat transfer tube. Set high. Furthermore, in this embodiment, in order to prevent the fluid containing the radioactive material from moving to the downstream side, the contaminated or potentially contaminated fluid flows outside the relatively low-pressure heat transfer tube. The uncontaminated fluid is circulated in a relatively high pressure heat transfer tube. Thus, even if the heat transfer tube is damaged, the radioactive material flowing through the low pressure side flow path is prevented from entering the high pressure side heat transfer tube through the damaged portion.

  Therefore, in this embodiment, a predetermined pressure difference is formed between the primary side and the secondary side of the intermediate heat exchanger 21 and between the primary side and the secondary side of the heat exchanger 22. Therefore, in this embodiment, a pressurizing mechanism is provided.

  The pressurizing mechanism includes, for example, a pressurizing conduit 30 for pressurizing the primary side of the heat exchanger 22, a pressurizing conduit 31 for pressurizing the secondary side of the heat exchanger 22, and each conduit 30. , 31 is composed of a pressurizer 39, pressure control valves 40, 41, and check valves 42, 43.

  The pressurizer 39 stores a fluid having a predetermined pressure. A pressure control valve 40 and a check valve 42 are provided between the primary pressure line 30 and the pressurizer 39. A pressure control valve 41 and a check valve 43 are provided between the secondary pressure line 31 and the pressurizer 39. One check valve 42 allows a flow from the pressurizer 39 to the pipe 24 of the intermediate loop and prevents a reverse flow. The other check valve 43 allows a flow from the pressurizer 39 to the third pipe 26 and prevents a reverse flow.

  Normally, the pressure control valve 40 provided in the primary side pressurizing pipe 30 is opened, and the pressure of the pressurizer 39 is supplied to the intermediate loop pipe 24 via the primary side pressurizing pipe 30. ing. As a result, the pressure in the intermediate loop pipe 24 is maintained higher than the pressure in the first pipe 23 by a first pressure value (for example, 0.5 MPa). At the same time, the pressure in the third pipe 26 is lower than the pressure in the intermediate loop pipe 24.

  In the second predetermined case, the pressure control valve 40 provided in the primary-side pressurization pipeline 30 is closed, and the pressure control valve 41 provided in the secondary-side pressurization pipeline 31 is opened. As a result, the pressure of the pressurizer 39 is supplied to the third pipe 26 via the secondary-side pressurizing pipe 31, and the pressure in the third pipe 26 is a second pressure higher than the pressure in the pipe 24 of the intermediate loop. It is set higher by a value (for example, 0.5 MPa).

  A configuration example of the controller 50 will be described. The controller 50 is a device for controlling the operation of the reactor heat utilization system 20. The controller 50 includes, for example, an I / O unit (input / output unit) 51, an abnormality detection unit 52, a flow path switching control unit 53, and a pressure control unit 54.

  For example, detection signals from a plurality of sensors 55, 56, and 57 such as pressure sensors are input to the I / O unit 51. The I / O section 51 is connected to the gate valves 28, 29, the globe valves 32, 33, 34, the switching sections 44, 45, the pumps 35, 36, and the pressure control valves 40, 41. These control objects 28, 29, 32, 33, 34, 44, 45, 35, 36, 40, 41 are operated by outputting control signals.

  The abnormality detection unit 52 detects whether an abnormality has occurred in the intermediate heat exchanger 21 or an abnormality has occurred in the heat exchanger 22 based on detection signals from the sensors 55, 56, 57. Here, the abnormality in the heat exchanger is a state in which the fluid flowing through the low-pressure side passage enters the high-pressure side passage (inside the heat transfer tube) through the damaged portion of the heat transfer tube. Therefore, as the sensors 55 to 57, for example, a pressure sensor or a flow sensor can be used. Instead of or in addition to a sensor for detecting a flow rate change or a pressure change, a configuration using a sensor such as an acoustic sensor or a radiation detection sensor may be used.

  When an abnormal state is detected, the flow path switching control unit 53 switches the flow path by outputting a control signal to a globe valve or a gate valve as described later. The pressure control unit 54 controls the pressurizing mechanism to form a predetermined pressure difference.

  FIG. 3 is a configuration diagram of the reactor heat utilization system 20 including the heat transfer structure of the heat exchangers 21 and 22. The heat transfer tube 21A of the intermediate heat exchanger 21 is surrounded by a flow path 21B, and the fluid that flows through the heat transfer pipe 21A and the steam containing the radioactive material that flows through the surrounding flow path 21B pass through the tube wall of the heat transfer pipe 21A. Exchange heat. In FIG. 3, the heat transfer tube 21A is shown in a simplified manner as if it were provided in the flow channel 21B, but actually, a plurality of heat transfer tubes 21A are provided in the flow channel 21B. The plurality of heat transfer tubes 21A may be provided in parallel with each other or in different directions.

  The heat exchanger 22 has a triple-structure flow path 22A, 22B, 22C. A second pipeline 22B is coaxially provided on the outer circumference side of the first pipeline 22A located in the center, and a third pipeline 22C is provided coaxially on the outer circumference side of the second pipeline 22B. Yes. The inner diameters increase in the order of the pipes 22A, 22B, and 22C (φ22A <φ22B <φ22C). As described in the intermediate heat exchanger 21, FIG. 3 shows a simplified structure as if the structure of one pipe line 22A, 22B is provided in the flow path 22C. Structures 22A and 22B are provided in the flow path 22C. The structures of the plurality of pipelines 22A and 22B may be provided in parallel to each other or in different directions.

  In a normal state, the intermediate loop pipe 24 is connected to the second pipe line 22B, and the switching units 44 and 45 connect the third pipe 26 to the third pipe line 22C. When an abnormal state is detected as will be described later, the switching units 44 and 45 connect the third pipe 26 to the first pipe line 22A. At this time, the pressure from the pressurizer 39 is supplied to the third pipe 26, and the pressure in the third pipe 26 is set higher than the pressure in the pipe 24 of the intermediate loop.

  FIG. 4 is a flowchart showing the safety control process of the reactor heat utilization system 20. As described below, the reactor heat utilization system 20 has multiple safety measures.

  As a first safety measure, in the intermediate heat exchanger 21, the pressure of the secondary side fluid flowing in the heat transfer tube 21A is set to be higher than that of the primary side fluid flowing in the flow path 21B flowing outside the heat transfer tube 21A. Only the pressure value is set higher (S10). As a result, as shown in FIG. 5, even when the damaged portion F1 occurs in the heat transfer tube 21A of the intermediate heat exchanger 21, the fluid in the relatively low pressure first piping 23 is relatively high pressure in the intermediate loop piping. 24 can be prevented from entering.

  However, in the present embodiment, the second safety measure is prepared in consideration of the possibility that the first safety measure described in step S10 is broken. For example, if for some reason the differential pressure between the first pipe 23 and the intermediate loop pipe 24 is reduced or the heat transfer pipe 21A is seriously damaged, the radioactive material may enter the intermediate loop pipe 24. is there.

  Therefore, the controller 50 monitors whether an abnormal state has occurred in the intermediate heat exchanger 21 based on detection signals from the sensors 55 and 56, that is, whether intrusion of contaminants has occurred in the intermediate heat exchanger 21. (S11).

  When detecting an abnormal state in the intermediate heat exchanger 21 (S11: YES), the controller 50 outputs a control signal to the first gate valve 28 to open the valve and outputs a control signal to the second globe valve 33. And close the valve. Thereby, the secondary side of the intermediate heat exchanger 21 is disconnected from the primary side of the heat exchanger 22 as indicated by a two-dot chain line arrow in FIG. 6. The fluid circulates in a circulation circuit formed by the secondary side of the intermediate heat exchanger 21 and the first bypass pipe 25. In addition, since the flow path on the primary side of the heat exchanger 22 is closed, no fluid flows.

  The case where a predetermined abnormal state is detected in the intermediate heat exchanger 21 (S11: YES) corresponds to the “first predetermined case”. The content of step S12 is the second safety measure. By implementing the second safety measure, the intermediate heat exchanger 21 and the heat exchanger 22 can be disconnected, and the fluid contaminated with the radioactive substance can be suppressed from moving to the heat exchanger 22 side.

  However, for some reason, malfunction may occur in the globe valve 33 and / or the gate valve 28, or a control signal line to the globe valve 33 or the gate valve 28 may be disconnected. Therefore, the possibility that the secondary side of the intermediate heat exchanger 21 cannot be separated from the primary side of the heat exchanger 22 cannot be completely excluded.

  Therefore, the controller 50 determines whether or not the disconnection operation in step S12 has been completed normally (S13). When it is determined that the separation has been normally completed (S13: YES), the controller 50 continues the operation of step S12 until safety is confirmed by performing a maintenance / replacement operation or the like.

  If the controller 50 determines that the disconnection operation in step S12 has not been completed normally (S13: NO), the controller 50 connects the third pipe 26 to the central first pipe line 22A in the heat exchanger 22, and further The pressure in the three pipes 26 is set higher than the pressure in the pipe 24 in the intermediate loop by the second pressure value (S14). The case where the secondary side of the intermediate heat exchanger 21 and the primary side of the heat exchanger 22 are not successfully separated corresponds to the “second predetermined case”. The content of step S14 is the third safety measure.

  Specifically, the controller 50 outputs a control signal to the switching units 44 and 45 to switch the connection destination of the third pipe 26 in the heat exchanger 22 from the third pipe line 22C to the first pipe line 22A. The connection destination of the intermediate loop pipe 24 in the heat exchanger 22 remains the second pipe line 22B. Accordingly, the arrangement relationship between the intermediate loop pipe 24 and the third pipe 26 is reversed in the heat exchanger 22 between the normal time and the abnormality detection time. At normal times, as described above, the intermediate loop pipe 24 is located on the inner side and the third pipe 26 is located on the outer side. When an abnormality is detected, the third pipe 26 is located on the inner side, and the intermediate loop pipe 24 is located on the outer side.

  Simultaneously with the switching of the pipe line in the heat exchanger 22, the controller 50 outputs a control signal to the pressure control valves 40 and 41 to guide the pressure of the pressurizer 39 to the third pipe 26. As a result, the pressure P3 in the third pipe 26 becomes higher by the second pressure value Δp2 than the pressure P2 in the intermediate loop pipe 24 (P3 = P2 + Δp2). In order to suppress the vapor from the first pipe 23 from entering the intermediate loop pipe 24 via the intermediate heat exchanger 21, the pressure P2 in the intermediate loop pipe 24 is set to the pressure in the first pipe 23. It remains set higher than P1 by the first pressure value Δp1 (P2 = P1 + Δp1).

  Therefore, as shown in FIG. 7, even when the damaged portion F2 occurs in the heat exchanger 22 and the first conduit 22A and the second conduit 22B are in physical communication, the second conduit on the low pressure side. It can suppress that the fluid in 22B penetrate | invades in the 1st pipe line 22A of a high voltage | pressure side.

  Even if the pressure of the first pipe line 22A connected to the third pipe 26 is set higher than the pressure of the second pipe line 22B connected to the pipe 24 of the intermediate loop, the pressure in the second pipe line 22B is still passed through the breakage point F3. The possibility that the fluid enters the first pipe line 22A cannot be completely eliminated.

  Therefore, in the present embodiment, a fourth safety measure is further prepared. The controller 50 monitors whether the fluid has entered the third loop 26 from the intermediate loop pipe 24 in the heat exchanger 22 (S15). When the controller 50 finds fluid intrusion (S15: YES), as shown in FIG. 8, the secondary side of the heat exchanger 22 is disconnected from the third pipe 26, and the second bypass pipe 27 is connected to the heat exchanger. The secondary side of 22 is circulated (S16). Specifically, the controller 50 outputs a control signal to the second gate valve 29 to open the valve, and outputs a control signal to the third globe valve 34 to close the valve. Thereby, the fluid circulates through the second bypass pipe 27 on the secondary side of the heat exchanger 22, and the heat exchanger 22 is disconnected from the heat utilization device outside the figure.

  The case where the fluid intrudes from the low pressure side to the high pressure side in the heat exchanger 22 is the “third predetermined case”, and the content of step S <b> 16 corresponding to this is the fourth safety measure.

  According to this embodiment configured as described above, the intermediate heat exchanger 21 and the heat exchanger 22 are provided between the pipe 23 connected to the main steam system pipe 3 and the pipe 26 for heat utilization. Therefore, the steam containing the radioactive material and the fluid for heat utilization are not directly exchanged heat. Therefore, the safety is increased as compared with the configuration in which the intermediate heat exchanger 21 is not provided.

  Further, in this embodiment, the pressure of the intermediate loop pipe 24 is set higher than that of the first pipe 23 on the main steam system side, the high pressure intermediate loop pipe 24 is connected to the heat transfer pipe 21A, and the low pressure main steam system is connected. Since the first pipe 23 on the side is connected to the flow path 21B outside the heat transfer pipe 21A, even if the heat transfer pipe 21A of the intermediate heat exchanger 21 is damaged, the radioactive material is prevented from entering the pipe 24 of the intermediate loop. it can.

  In the present embodiment, when contaminated fluid enters the intermediate loop pipe 24 from the first pipe 23 on the main steam system side, the intermediate heat exchanger 21 and the heat exchanger 22 are separated from each other, and two intermediate heat exchangers 21 are provided. The fluid is circulated by bypassing the secondary side. Thereby, it can suppress that the fluid which may contain a radioactive substance flows into the heat exchanger 22. FIG.

  In the present embodiment, when the disconnection of the intermediate heat exchanger 21 fails, the pressure of the heat utilization pipe 26 is set higher than that of the pipe 24 of the intermediate loop, and the line in the heat exchanger 22 is switched to increase the pressure. The pipe 26 is connected to the central pipe line 22A, and the low-pressure intermediate loop pipe 24 is connected to the outer pipe line 22B. For this reason, it is possible to suppress a fluid that may contain a radioactive substance from entering the heat utilization system pipe 26 via the heat exchanger 22 from the intermediate loop pipe 24.

  In this embodiment, when the fluid from the intermediate loop pipe 24 enters the heat utilization system pipe 26 via the heat exchanger 22, the heat utilization system pipe 26 is disconnected from the heat exchanger 22, and the heat exchanger 22. The secondary side of the fluid is bypassed to circulate the fluid. Thereby, it can suppress that the fluid which may contain a radioactive substance penetrate | invades into the piping 26 of a heat utilization system.

  According to the present embodiment configured as described above, it is possible to provide a plurality of safety devices for preventing the radioactive material from entering the piping 26 of the heat utilization system, and to ensure the high safety of the nuclear reactor. The generated thermal energy can be used 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. For example, the valve structure or the type of sensor is not limited as long as it has an expected function. In addition, the present embodiment can be suitably used for a boiling water light water reactor, but is not limited to this, and can also be applied to a pressurized water light water reactor.

  1: reactor core, 2: reactor vessel, 3; main steam system piping, 4: high pressure turbine, 5: low pressure turbine, 11: feed and condensate system piping, 20: reactor heat utilization system, 21: intermediate heat exchanger, 22 : Heat exchanger, 23: main steam side pipe, 24: intermediate loop pipe, 25: first bypass pipe, 26: heat utilization side pipe, 27: second bypass pipe, 28, 29: gate valve, 30 , 31: Pressurizing pipe line, 32-34: Globe valve, 35, 36: Pump, 37, 38, 42, 43: Check valve, 40, 41: Pressure control valve, 44, 45: Switching unit, 50: Controller, 55-57: Sensor

Claims (7)

A reactor heat utilization system that uses the heat of a reactor,
A first pipe into which a part of the high-temperature gas refrigerant taken out from the nuclear reactor flows,
A second pipe through which the refrigerant circulates;
A first heat exchanger for exchanging heat between the first pipe and the second pipe by connecting the first pipe to the primary side and connecting the second pipe to the secondary side;
A third pipe for heat utilization;
A second heat exchanger that exchanges heat between the second pipe and the third pipe by connecting the second pipe to the primary side and connecting the third pipe to the secondary side;
In the normal case, the secondary side of the first heat exchanger and the primary side of the second heat exchanger are connected, and in the first predetermined case, the secondary side of the first heat exchanger and the second side A first flow path control mechanism for separating the primary side of the heat exchanger, bypassing the secondary side of the first heat exchanger and circulating the refrigerant;
A first pressure adjusting unit for adjusting the pressure of the second pipe to be higher than the pressure of the first pipe by a first pressure value;
Reactor heat utilization system. The first predetermined case is a case where it is determined that the refrigerant has flowed into the second pipe from the first pipe in the first heat exchanger.
The reactor heat utilization system according to claim 1. The second heat exchanger surrounds the first pipe, the second pipe provided outside the first pipe so as to surround the first pipe, and the second pipe. A third pipe provided outside the second pipe, and a heat transfer structure having a concentric triple structure;
Connecting the second pipe to the second pipe;
In the normal case, the third pipe is connected to the third pipe, and in the second predetermined case, the third pipe is connected to the first pipe.
The reactor heat utilization system according to claim 2. A second pressure adjusting unit configured to increase the pressure of the third pipe by a second pressure value than the pressure of the second pipe in the second predetermined case;
The reactor heat utilization system according to claim 3. The second predetermined case is a case where the first flow path control mechanism portion does not operate normally despite the occurrence of the first predetermined case.
The reactor heat utilization system according to claim 4. Furthermore, a second flow path control mechanism is provided,
The second flow path control unit connects the secondary side of the second heat exchanger and the third pipe in a normal case, and the secondary of the second heat exchanger in a third predetermined case. Separating the side and the third piping, bypassing the secondary side of the second heat exchanger and circulating the refrigerant,
The reactor heat utilization system according to claim 5. The third predetermined case is a case where it is determined that the refrigerant has flowed from the second pipe into the third pipe in the second heat exchanger.
The reactor heat utilization system according to claim 6.

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