JP4466545B2 - Reactor water supply equipment - Google Patents

Description

  The present invention relates to a water supply apparatus that controls the supply of water to a nuclear reactor, and in particular, when the operation of a nuclear reactor is performed by lowering the temperature of the water supplied to the reactor pressure vessel as compared to the rated heat output operation at the beginning of construction. Even so, the present invention relates to a reactor water supply apparatus suitable for maintaining the soundness of the reactor pressure vessel.

  In the design of a normal boiling water reactor, the thermal power of the core is first determined, and the steam flow after the main steam pipe is optimized so that the highest thermal efficiency can be obtained with that thermal output. Specifically, when steam is converted into water by a condenser, 2/3 of the energy is discharged at a normal boiling water reactor pressure (about 7 MPa) from the principle of thermal cycle.

  Therefore, as described above, a part of the steam is extracted and used to heat the feed water in the feed water heater. In this case, since the heat of the extracted steam extracted is recovered, the thermal efficiency of the nuclear reactor is improved. Generally, in a boiling water reactor equipped with a moisture separator using a recirculation pump and a jet pump, the amount of steam finally sent from the low-pressure turbine outlet to the condenser is about 55%. The remaining steam is used to heat the feed water.

  In the conventionally known Patent Document 3, a method for lowering the feed water temperature without increasing the main steam flow rate and the feed water flow rate is proposed in order to suppress an increase in the load on the feed water pipe, the main steam pipe, and the structure in the reactor. Has been.

  At this time, a large temperature difference occurs between the high-temperature reactor water and the low-temperature water supply in the water supply nozzle portion, and there is concern about thermal stress and thermal fatigue in the water supply nozzle portion. Therefore, a water supply system excellent in heat stress and heat fatigue is required.

  Furthermore, the water supply system to the reactor pressure vessel is connected to the reactor adopted in the nuclear power plant. The water supply pipe of the water supply system is connected to the inlet 1 a of the water supply nozzle 1 of the reactor pressure vessel 11 shown in FIG. 3 and communicates with the thermal sleeve 3 in the water supply nozzle 1. A T-tube 6 having a T-shaped flow path is connected to one end of the thermal sleeve 3 inside the reactor pressure vessel 11, and a header tube 35 is connected to the other two ends of the T-tube 6. The header pipe 35 is horizontally provided along the inner wall surface of the reactor pressure vessel. The water injection nozzle 2 is installed in the header pipe 35 with the water supply discharge port 36 facing in the horizontal direction toward the center of the reactor pressure vessel.

  The water supply nozzle 1, the thermal sleeve 3, the T-shaped tube 6, the water injection nozzle 2, the header pipe 35, etc. are located below the surface of the reactor water during the rated operation of the reactor. Exposed to reactor water 7 In such a high-temperature environment, the water supply 8 having a temperature lower than the temperature of the high-temperature reactor water 7 in the reactor pressure vessel is injected from the water injection nozzle 2 through the water supply system above the downcomer of the reactor pressure vessel. It is discharged in the horizontal direction toward the direction.

  As described above, since the water supply 8 having a temperature lower than the temperature of the high-temperature reactor water 7 passes through the thermal sleeve 3, the annular flow path 9 between the thermal sleeve 3 and the water supply nozzle 1 is provided as shown in FIG. 4. A high / low temperature water interface 22 between the high temperature water 20 and the low temperature water 21 is generated, and the lower side is exposed to a low temperature and the upper side is exposed to a high temperature.

  Under such circumstances, when the low temperature water supply 8 is discharged from the water injection nozzle 2 into the reactor pressure vessel, the flow of the water supply is changed to the shroud head bolt 4 or the shroud head bolt ring 5 to have the low temperature water supply. The rebound water 23 may be generated and enter the annular flow path 9 as shown in FIG.

In such a state, the flow is generated in the annular flow path 9 and the position of the high / low temperature water interface 22 fluctuates in spite of the dead end annular flow path 9 on the inlet 1a side of the water supply nozzle 1. Thermal shock is continuously generated in the nozzle 1 and the thermal sleeve 3. Even if the low-temperature rebound water 23 does not enter the annular flow path 9, the rebound water 23 comes into contact with the vicinity of the root portion of the reactor pressure vessel 11 of the water supply nozzle 1, so that part is subjected to thermal shock.

  The occurrence of such a thermal shock can be considered that low-temperature rebound water 23 is generated in the standpipe even when the shroud head bolt 4 and the shroud head bolt ring 5 are not arranged close to the water injection nozzle 2. May occur. Avoiding such thermal shocks as much as possible should be considered when further improving the safety of the reactor.

  Further, the temperature of the above-mentioned rebound water 23 rises when heat is exchanged in the thermal sleeve 3 or when it is discharged into the reactor pressure vessel 11, but it may be lower than the temperature of the low-temperature water 21 that forms the high-low temperature water interface 22. Presumed. Therefore, if the rebound water 23 discharged from the water injection nozzle 2 directly acts on the high / low temperature water interface 22, the temperature fluctuation range becomes large, and thermal fatigue is likely to occur in the water supply nozzle 1 and the thermal sleeve 3. There is.

  Patent Document 1 is listed as an example of preventing thermal shock at the water supply nozzle portion of the reactor pressure vessel, and Patent Document 2 is listed as an example of employing a thermal sleeve in the nozzle.

JP 55-48696 A JP 2005-201696 A

  As in Patent Document 1, by changing the height position of the water supply nozzle to a height that exceeds the water level of the reactor water during the rated operation of the reactor, it is possible not to be affected by each temperature of the reactor water or water supply. In order to eliminate thermal fatigue caused by thermal shock, which is a concern with water supply nozzles, it has been considered. However, in the nuclear reactors used in the power plants of existing nuclear power plants, the feed water nozzle is arranged at a level below the surface of the reactor water in the reactor pressure vessel, so the feed water nozzle and the reactor vessel interior If the positional relationship with the liquid level of the reactor water is changed, there is a concern that the performance of the steam-water separator and the steam dryer installed in the reactor pressure vessel can be secured.

  Therefore, in order to ensure the performance of the equipment in the reactor pressure vessel, thermal fatigue due to the thermal shock of the water supply nozzle portion with the water supply nozzle installed below the level of the reactor water in the reactor pressure vessel. It is desirable to avoid it.

  Another patent document 2 is similar in that a thermal sleeve is used in the nozzle part, but the purpose is to stabilize the cooling water injection flow rate, and mention is made of thermal shock and thermal fatigue of the water supply nozzle part. Absent.

  Accordingly, an object of the present invention is to achieve water supply to a reactor pressure vessel in which a water supply nozzle is disposed at a level below the surface of the reactor water while avoiding thermal shock as much as possible.

The basic requirements of the present invention are a reactor pressure vessel, a steam system for supplying steam from the reactor pressure vessel to a high pressure turbine and a low pressure turbine, and a condenser for condensing steam discharged from the low pressure turbine into water. And a water supply system that heats the water with a feed water heater and guides the water toward the reactor pressure vessel through a water supply pipe with a pump, and is disposed at a height lower than the reactor operating water level in the reactor pressure vessel. The reactor pressure vessel feed nozzle, the thermal nozzle provided in the feed nozzle and in communication with the feed pipe, the reactor pressure vessel in the reactor, and in communication with the thermal sleeve A reactor water supply apparatus comprising: a header pipe; and a water injection nozzle that is disposed at a lower level than the reactor operating water level and communicates with the header pipe to discharge the water into the reactor pressure vessel. Oite, the header pipe is equipped with are connected by the communicating pipe in the vertical multistage, together with the water injection nozzle header pipe of the lower is equipped, the height direction of the discharge port for discharging the water in the water injection nozzle A water supply device for a reactor, the center position of which is disposed below the center position in the height direction of the thermal sleeve.

  According to the present invention, the discharge position into the reactor pressure vessel by the water injection nozzle is lower than the height of the central axis of the water supply nozzle, and the discharge is performed in the flow of reactor water descending along the inner wall surface of the reactor pressure vessel. The subsequent water supply is accompanied and descends, and it becomes difficult to reach the upper water supply nozzle, and the occurrence of thermal shock at the water supply nozzle portion can be suppressed.

  A first embodiment of the present invention will be described below. As shown in FIG. 9, a nuclear power plant nuclear reactor includes a main steam system and a water supply system connected to the reactor pressure vessel 11. The main steam system is a system that supplies steam from the reactor pressure vessel 11 to the high-pressure turbine 26 and the low-pressure turbine 28.

  That is, the high-temperature and high-pressure steam generated in the reactor pressure vessel 11 is supplied to the high-pressure turbine 26 through the main steam pipe 19 and used to rotate the high-pressure turbine 26. The steam used in the high-pressure turbine 26 is supplied to the moisture separator 27 to reduce the moisture. The steam with reduced moisture is supplied to the low-pressure turbine 28 and used to rotate the low-pressure turbine 28. Thus, the steam used in each turbine of the main steam system is supplied to the condenser, where the steam is condensed into low-temperature water.

  When the high-pressure turbine 26 and the low-pressure turbine 28 are rotationally driven, the generator connected to each turbine is driven by the rotational driving force of each turbine to exert a power generation action, and the generated power is output to the outside of the nuclear power plant with a cable. It is configured to transmit power.

  After the steam used in each turbine is returned to low-temperature water by the condenser 29, the water is handled as water supply in the water supply system. The water supply system is as follows. That is, in the water supply system, water generated from the steam in the condenser 29 is supplied as water to the water supply pipe 37, and the water is supplied into the reactor pressure vessel 11 by the water supply pump 31. A low-pressure feed water heater 30 and a high-pressure feed water heater 32 are provided in series in the middle of the feed water pipe 37 to heat the feed water passing through the feed water system.

Steam is extracted and supplied from the intermediate stage of the moisture separator 27 and the low-pressure turbine 28 to the low-temperature feed water heater 30 of the feed water system as a fluid subject to heat exchange with the feed water. Similarly, steam is extracted and supplied from the intermediate stage and the final stage of the high-pressure turbine 26 to the high-pressure feed water heater 32 of the feed water system as a fluid subject to heat exchange with the feed water. In the middle of the pipe for supplying the steam extracted from the final stage of the high-pressure turbine 26 to the high-pressure feed water heater 32, an extraction flow rate adjustment valve 33 is provided, and the amount of steam supplied to the high-temperature feed water heater is extracted. It can be adjusted by adjusting the opening.

  Further, the water supply system includes a water supply bypass pipe 34 for bypassing the high-pressure feed water heater 32, a pipe for supplying steam, which is a heat source in the high-pressure feed water heater 32, to the low-temperature feed water heater 30, and a low-temperature feed water heater. A pipe or the like for supplying a fluid such as steam as a heat source 30 to the condenser 29 is attached.

  The water supply system can guide the temperature of the feed water at the inlet of the feed water nozzle into the reactor pressure vessel 11 by lowering the temperature by 1 ° C. or more from the temperature at the rated operation at the beginning of the construction of the reactor. Further, the flow rate of supplying steam (heat source) in the high-pressure turbine 26 to the high-pressure feed water heater 32 is reduced by performing an operation of closing (in the closing direction) the extraction flow rate adjusting valve 33 from the rated operation at the beginning of construction.

  Alternatively, the feed water from the feed water pump 31 is not supplied to the high-pressure feed water heater 32, but is fed directly to the reactor pressure vessel 11 through the feed water bypass pipe 34. The operating condition is to improve the output by reducing it by 1 ° C. or more from the water supply temperature at the inlet of the water supply nozzle during the initial rated operation. The water supply bypass pipe 34 is provided with a flow rate adjustment valve, the opening of the flow rate adjustment valve is adjusted to adjust the flow distribution of the water supply to the water supply bypass pipe 34 and the high pressure feed water heater 32, and at the inlet of the water supply nozzle. The temperature of the water supply may be reduced by 1 ° C. or more from the water supply temperature at the inlet of the water supply nozzle at the time of rated operation at the beginning of construction so as to be an output improvement operation condition.

  Thus, the feed water temperature may be lowered by 1 ° C. or more, which is equal to or greater than the fluctuation width of the feed water temperature during normal operation. However, since the feed water is mixed with water at the saturation temperature in the reactor pressure vessel 11 when entering the reactor pressure vessel 11, a temperature difference occurs between components near the feed water nozzle portion. If the feed water temperature is lowered too much, the temperature difference increases at this portion, and there is a concern that the design limit will be exceeded from the viewpoint of thermal fatigue. Therefore, the reduction width is set in consideration of the balance with the design limit so that there is no concern.

  In FIG. 9, Q represents the percentage of heat output generated in the reactor pressure vessel, G represents the mass flow percentage in the system of FIG. 9, and H represents enthalpy (kJ / kg). In FIG. 9, Q = 105 means that the power output percentage Q of the rated heat output at the beginning of the reactor construction was increased to 105% after the construction.

  FIG. 2 shows the configuration of the reactor pressure vessel 11 in the improved boiling water reactor. A core 17 is installed in the shroud 12 in the reactor pressure vessel 11. Water is boiled in the core 17 containing fissile material, and the steam generated by the boiling flows into the steam separator 13 in a mixed state with warm water, and is separated into steam containing droplets and warm water.

  The hot water separated by the steam separator 13 is mixed with the feed water from the feed nozzle 1 into the reactor pressure vessel 11 and the downcomer 14 formed between the reactor pressure vessel 11 and the shroud 12 is directed downward. Then, it is driven by a recirculation pump 15 provided at the bottom of the reactor pressure vessel 11 and recirculated to the core 17 via the lower plenum 16.

  On the other hand, the steam containing the droplets separated by the steam separator 13 is removed from the steam by the steam dryer 18 disposed above the steam separator 13. It is sent to the high-pressure turbine 26 and the low-pressure turbine 28 via, and electricity is generated by the generator interlocked with the shafts of the high-pressure turbine and the low-pressure turbine.

  Steam used in each turbine is condensed into water by a condenser 29, and the water is adjusted in temperature by each feed water heater as feed water, and is pressurized by a feed water pump 31, passes through the inside of the feed water nozzle 1, and is a water injection nozzle. 2 is discharged into the reactor pressure vessel 11 and supplied with water. A plurality of water supply nozzles 1 are provided in the circumferential direction of the reactor pressure vessel 11. The discharge direction of the feed water from the water injection nozzle 2 is the horizontal direction toward the reactor pressure vessel 11 center indicated by the one-dot chain line in FIG. 3B so that the hot water and the cooling water are uniformly mixed in the horizontal section. It has become.

  FIG. 1 shows the structure of the feed water nozzle 1 part of the improved boiling water reactor. In order to reduce thermal stress and thermal fatigue due to the temperature difference between the high-temperature reactor water 7 descending in the reactor pressure vessel 11 and the feed water 8 having a temperature lower than that of the reactor water, the feed nozzle 1 and The thermal sleeve 3 is installed concentrically to avoid contact between two fluids having a direct temperature difference in the water supply nozzle 1. An annular channel 9 is provided between the inner wall surface of the water supply nozzle 1 and the outer wall surface of the thermal sleeve 3.

  One end of the thermal sleeve 3 is integrated with a portion of the water supply nozzle 1 near the water supply inlet 1a. A T-shaped T-shaped tube 6 is connected to the tip which is the other end of the thermal sleeve 3, and left and right header tubes 35 are connected to the left and right ends of the T-shaped tube 6. A plurality of L-shaped water injection nozzles 2 are connected.

  As shown in FIG. 1, the water injection nozzle 2 is connected to the lower position of the header pipe 35, and the water supply discharge port 36 is horizontally directed toward the center of the reactor pressure vessel 11 as indicated by the one-dot chain line in FIG. Facing the direction. Water is discharged from the discharge port 36 of the water injection nozzle 2 in the horizontal direction toward the center of the reactor pressure vessel 11 and supplied into the reactor pressure vessel 11. The central axis 2 a of the water injection nozzle 2 passing through the center of the discharge port 36 is disposed below the central axis 3 a common to the thermal sleeve 3 and the water supply nozzle 1.

  A shroud head bolt 4 and a shroud head bolt ring 5 are arranged in the vicinity of the header pipe 35 as shown in FIG. Since the normal operating water level of the reactor water during the rated operation of the nuclear reactor is at the level indicated by the arrows AA shown in FIG. 2B, the water supply nozzle 1 provided at a position lower than that level. Is filled with high-temperature reactor water, and the shroud head bolt ring 5, the water injection nozzle 2, the header tube 35, the T-shaped tube 6 and the thermal sleeve 3 exist in the high-temperature reactor water. Naturally, the high-temperature reactor water 7 is also filled in the annular flow path 9 between the inner surface of the water supply nozzle 1 and the outer surface of the thermal sleeve 3.

  Next, the flow of the high-temperature reactor water 7 in the reactor pressure vessel 11 and the low-temperature feed water 8 from the feed water nozzle 1 will be described. High-temperature reactor water 7 (for example, 280 ° C.) separated from steam by the steam-water separator 13 in the reactor pressure vessel 11 flows from above the water injection nozzle 2. Thereafter, the high temperature reactor water 7 is mixed with the low temperature feed water 8 discharged from the water injection nozzle 2, passes through the downcomer 14, is driven by the recirculation pump 15, and is recirculated to the core 17 via the lower plenum 16. The

  The low temperature water supply 8 passes through the thermal sleeve 3 in the water supply nozzle 1 from the water supply pipe 37, is divided into two directions by the T-shaped pipe 6, passes through the header pipe 35 in the two directions, and enters each water injection nozzle 2. Then, it is discharged into the reactor pressure vessel 11 from the discharge port 36 of each water injection nozzle.

  Since the direction of the discharge port 36 of the water injection nozzle 2 is horizontal toward the center of the reactor pressure vessel 11, the low-temperature water supply 8 discharged into the reactor pressure vessel 11 is centered on the reactor pressure vessel 11. It is mixed with hot reactor water 7 while moving and diffusing horizontally.

  When the vicinity of the outlet of the water injection nozzle 2 is viewed from the direction of the arrow A in FIG. 1 (b), as shown in FIG. Therefore, water can be supplied over a wide range in the reactor pressure vessel 11. Therefore, mixing of the high temperature reactor water 7 and the low temperature feed water 8 can be promoted.

  Further, immediately after the low-temperature water supply 8 discharged into the reactor pressure vessel 11 is discharged from the water injection nozzle 2, it does not instantaneously rebound to the water supply nozzle 1 side. Accordingly, the annular flow path 9 between the inner surface of the water supply nozzle 1 and the outer surface of the thermal sleeve 3 is restrained from changing to the high / low temperature water interface 22 formed as shown in FIG. Generation | occurrence | production can be prevented and the structural soundness of the water supply nozzle 1 can be improved.

  Further, there is nothing that obstructs the discharge of water supply on the extension line of the central axis 2 a of the water injection nozzle 2, but there is a structure in the central part in the reactor pressure vessel 11. Further, since the circulation flow rate of the high-temperature reactor water 7 is larger than the feed water flow rate from the water injection nozzle 2, the flow of the high-temperature reactor water 7 is dominant in the flow in the reactor pressure vessel 11.

From the above, the low-temperature water supply 8 discharged into the reactor pressure vessel 11 has a rebounding flow to the water supply nozzle 1 side, although not instantaneously. Since the high temperature reactor water 7 flows downward from above the water injection nozzle 2 and the low temperature water supply 8 is discharged in the horizontal direction, the low temperature water supply 8 rebounds to a position higher than the height position of the water injection nozzle 2. There is no. On the other hand, the central axis 2 a of the water injection nozzle 2 is also the central axis of the discharge port 36, but the position of the central axis 2 a including the central axis 3 a of the thermal sleeve 3 is set below the position. Therefore, the influence of the rebound water 23 on the temperature fluctuation at the high / low temperature water interface 22 formed between the inner surface of the water supply nozzle 1 and the outer surface of the thermal sleeve 3 can be reduced. In addition, since arrangement | positioning of the water injection nozzle 2 can respond | correspond only by changing an installation place from the upper part of the header pipe 35 to the lower part compared with the past, this Example can be implement | achieved easily.

  Further, the rebound water 23 may collide with the inner wall surface of the reactor pressure vessel 11 below the water supply nozzle 1. However, the shroud head bolt ring 5 is not rebounded when the water supply hits it, and rebounds on the central axis side of the reactor pressure vessel 11 with respect to the shroud head bolt ring 5. 8 is sufficiently mixed in the reactor pressure vessel 11 and bounces back, and the force of the bounce also declines. Therefore, the impact on the thermal stress and thermal fatigue when the water 23 collides with the inner wall of the reactor pressure vessel 11 and collides with the water 23 Can be suppressed or eliminated.

  In this embodiment, the outlet direction of the water injection nozzle 2 is the horizontal direction toward the center of the reactor pressure vessel 11, but substantially the same effect can be obtained even in the diagonally downward direction.

  A second embodiment of the present invention is shown in FIG. The feature of the present embodiment is that the highest position of the surface of the discharge port 36 of the water injection nozzle 2 is lower than the lower position of the inner wall surface of the water supply nozzle 1. More preferably, the highest position of the surface of the discharge port 36 of the water injection nozzle 2 is set lower than the position where the inner wall surface of the water supply nozzle 1 and the inner wall surface of the reactor pressure vessel 11 are in contact. Other configurations are the same as those of the first embodiment described above.

  In the case of the second embodiment, compared with the first embodiment of FIG. 1, the length of the water injection nozzle 2 attached to the header pipe 35 is made longer, and the height of the central axis 2 a of the discharge port 36 of the water injection nozzle 2 is increased. The position is even lower. Therefore, even if rebounding water is generated, temperature fluctuations at the high / low temperature water interface formed between the inner surface of the water supply nozzle 1 and the outer surface of the thermal sleeve 3 can be more reliably suppressed. In addition, about the attachment location of the water injection nozzle 2, since it can respond only by changing the installation place to the header pipe 35 of the water injection nozzle 2 of a prior art example similarly to the Example of FIG. 1, this Example is easy. Can be realized.

  Further, the rebound water may collide with the inner wall surface of the reactor pressure vessel 11 below the water supply nozzle 1. However, since the high-temperature reactor water 7 and the low-temperature feed water 8 are sufficiently mixed in the reactor pressure vessel 11 and rebounded, there is no influence on thermal stress and thermal fatigue at the time of collision with the inner wall of the reactor pressure vessel 11.

  In this embodiment, the direction of the discharge port 36 of the water injection nozzle 2 is the horizontal direction toward the center of the reactor pressure vessel 11, but substantially the same effect can be obtained even in a diagonally downward direction.

  A third embodiment of the present invention is shown in FIG. The feature of this embodiment is that one water injection nozzle 2 has two discharge ports 36 for water supply, one of which is a horizontal discharge port 36a toward the center of the reactor pressure vessel 11, and the other. One is a downward discharge port 36b. Other configurations are the same as those of the first embodiment.

  In this embodiment, there are two discharge ports 36a and 36b of the water injection nozzle 2, and the high-temperature reactor water 7 and the low-temperature feed water 8 can be mixed not only in one direction but also in two directions, leading to the promotion of mixing.

  In this embodiment, there are two discharge ports 36a, 36b of the water injection nozzle 2. However, even if there are three or more discharge ports in the discharge direction that guides the water supply after discharge to the upward flow, Similar effects can be obtained. In this embodiment, the discharge ports 36a and 36b of the water injection nozzle 2 are oriented horizontally and downward toward the center of the reactor pressure vessel 11, but horizontally and obliquely downward toward the center of the reactor pressure vessel 11 or atoms. A similar effect can be obtained by a diagonally downward and downward combination toward the center of the furnace pressure vessel 11.

  A fourth embodiment of the present invention is shown in FIG. The feature of this embodiment is that the height position of the central axis 2a of the water injection nozzle 2 is set higher than the height position of the central axis 3a of the thermal sleeve 3 and the water supply nozzle 1 while the water injection nozzle 2 is installed on the header pipe 35. The surface of the discharge port of the water injection nozzle 2 is preferably lower than the position below the lower inner wall surface of the water supply nozzle 1.

  In this embodiment, the pipe portion forming one side of the T-shape of the T-tube 6 is extended and bent at a right angle, and the extended end portion is connected to the thermal sleeve 3. By extending the T-shaped tube 6, the outlet of the water injection nozzle 2 is disposed at a position lower than the position below the lower inner wall surface of the water supply nozzle 1 as described above. Other configurations are the same as those of the first embodiment.

  In this way, the extension pipe portion of the T-tube 6 from the thermal sleeve 3 bends downward, and the header tube 35 connected to the T-tube 6 is disposed at a lower position than the above-described embodiments. Therefore, the lower inner wall surface of the water supply nozzle 1 is hidden by the T-shaped tube 6 bent downward. Therefore, the flow of the high-temperature reactor water 7 can be suppressed together with the flow of bounce water that affects the temperature fluctuation to the high and low temperature water interface formed in the annular flow path 9 between the inner surface of the water supply nozzle 1 and the outer surface of the thermal sleeve 3. The flow of the high-temperature reactor water 7 hits the upper part of the header pipe 35 or is swirled and disturbed at the lower part of the header pipe 35 and easily enters the annular flow path 9, but the height position of the header pipe 35 is the water supply nozzle 1. Since it is in a lower position than that, it is possible to prevent water supply or high-temperature reactor water 7 from entering the annular flow path 9.

  In this embodiment, the structure of the water injection nozzle 2 is the same as that of the current structure. However, the structure and arrangement of the water injection nozzle 2 shown in the embodiments of FIGS. There is no problem even if it is applied to the lowered header pipe 35.

  A fifth embodiment of the present invention is shown in FIG. The feature of the present embodiment is that a lower header pipe 25 is disposed below the header pipe 35, and the lower header pipe 25 is connected to the upper header pipe 35 through a communication pipe 24. A water injection nozzle 2 having a discharge port oriented in the horizontal direction is connected to the part. The water injection nozzle 2 is composed of a horizontal straight short pipe, and its central axis 2a is lower than the central axis 3a of the water supply nozzle 1, and preferably, the discharge port of the water injection nozzle 2 is the water supply nozzle. 1 is disposed at a position lower than a position below the lower inner wall surface. Other configurations are the same as those of the first embodiment.

  In the present embodiment, low temperature water supply 8 is discharged from the water injection nozzle 2 through the thermal sleeve 3, the T-shaped tube 6, the communication tube 24, and the lower header tube 25. Since the gap between the T-shaped pipe 6 and the lower header pipe 25 is narrow, it affects the temperature fluctuation to the high / low temperature water interface formed in the annular flow path 9 between the inner surface of the water supply nozzle 1 and the outer surface of the thermal sleeve 3. The flow of the rebounding water and the flow of the high-temperature reactor water 7 can be suppressed.

  As described above, if the existing boiling water reactor water supply system is replaced with the water supply system according to any of the embodiments of the present invention and the operation is performed with improved output, the water supply temperature will be lower than the conventional one. However, it is possible to maintain sufficiently high reliability, and an effective nuclear power generation system capable of increasing the electric output as compared with the current plant operation.

  According to the embodiment of the present invention, the water supply nozzle, the thermal sleeve, the T-shaped tube, and the water injection nozzle are disposed below the level of the circulating reactor water in the pressure vessel during rated operation, and the central axis of the outlet surface of the water injection nozzle By providing the position below the center axis position of the thermal sleeve, there is nothing to block the discharge of feed water near the outlet of the water injection nozzle, so a wide range of hot reactor water and cold feed water are mixed in the reactor pressure vessel. Can be made. In addition, by lowering the outlet position of the water injection nozzle, even if the water supply bounces from the center of the reactor pressure vessel, it affects the temperature fluctuations at the high and low temperature water interface formed between the inner surface of the water supply nozzle and the outer surface of the thermal sleeve. Can be reduced. Further, since the rebound water is sufficiently mixed in the reactor pressure vessel, there is no problem even if the rebound water collides with the inner wall surface of the reactor pressure vessel.

  The water supply nozzle, thermal sleeve, T-tube and water injection nozzle are arranged below the level of the circulating water in the pressure vessel during rated operation, and the lower inner wall surface of the water supply nozzle and the inner wall surface of the reactor pressure vessel are In accordance with the embodiment in which the outlet surface of the water injection nozzle is provided below the contact position, the high temperature reactor water and the low temperature water supply can be mixed in a wide range in the reactor pressure vessel, and the outlet of the water injection nozzle can be mixed. By lowering the position, even if the water supply bounces from the center of the reactor pressure vessel, there is no effect on the temperature fluctuation at the high and low temperature water interface formed between the inner surface of the water supply nozzle and the outer surface of the thermal sleeve. It collides with the reactor pressure vessel wall below the water supply nozzle. Further, since the rebound water is sufficiently mixed in the reactor pressure vessel, there is no problem even if the rebound water collides with the inner wall surface of the reactor pressure vessel. Therefore, it is possible to improve the structural integrity that can more reliably suppress thermal stress and thermal fatigue.

  Further, in the embodiment in which a plurality of water injection nozzle discharge ports are provided, the range of mixing with the reactor water of the feed water in the reactor pressure vessel is widened, so that the splashed water collides with the inner wall surface of the reactor pressure vessel. There is no problem.

  By setting the outlet direction of the water injection nozzle in the horizontal direction toward the reactor pressure vessel center, or in the diagonally downward direction toward the reactor pressure vessel center, or in the downward direction, from the high-temperature reactor water and the injection nozzle in the reactor pressure vessel Leads to the promotion of mixing of low temperature water supply.

  In an embodiment in which the discharge port direction of the water injection nozzle is a horizontal direction toward the center of the reactor pressure vessel and an obliquely downward direction or downward direction toward the center of the reactor pressure vessel, the hotter reactor water and the lower temperature water supply are combined. Leads to the promotion of mixing.

  The water supply nozzle, thermal sleeve, T-tube and water injection nozzle are located below the level of circulating reactor water in the pressure vessel during rated operation, and a lower horizontal pipe is provided below the T-tube of the water supply nozzle. In an embodiment in which the pipe and the T-shaped pipe are connected by a communication pipe, the water injection nozzle is provided on the lower horizontal pipe, and the center axis position of the outlet surface of the water injection nozzle is provided below the center axis position of the thermal sleeve. Since there is a structure in the vicinity of the annular flow path on the reactor pressure vessel side of the nozzle, it is difficult to be affected by the splashed water, and a water supply nozzle with improved structural soundness that can suppress thermal stress and thermal fatigue can be realized.

  A water supply system according to any of the embodiments is installed in a reactor whose power output has been increased by increasing the heat output from the rated heat output at the time of reactor construction, and the temperature of the feed water nozzle inlet to the reactor pressure vessel is Even below the temperature set at the time of construction, it can contribute to improving the output of nuclear power generation while maintaining or improving the structural integrity of the water supply nozzle.

  Adopting one of the embodiments of the present invention to a reactor whose power output has been increased more than the rated heat output at the time of reactor construction, the feed water nozzle inlet temperature during rated operation after the reactor power has been improved Can improve the output of nuclear power generation while maintaining or improving the structural soundness of the feed water nozzle even in the power improvement operation where the temperature is lowered by 1 ° C. or more than the inlet temperature of the feed water nozzle at the rated operation at the time of reactor construction.

  In any of the embodiments, in the nuclear power generation system, when the core thermal output is increased, in the operation method in which heat is removed by lowering the feed water temperature without increasing the amount of steam generated from the reactor, the temperature at the feed water nozzle section Even if the reactor water and feed water with a large difference are mixed, the temperature fluctuation disturbance to the high and low temperature water interface formed in the annular flow path between the inner surface of the feed water nozzle and the outer surface of the thermal sleeve can be suppressed. Since the occurrence of the high cycle thermal fatigue caused can be prevented, the electrical output of the nuclear power plant can be increased without imposing a burden.

  The present invention is used for a water supply system attached to a nuclear power plant reactor.

The figure which shows the structure of the water supply nozzle part vicinity of the reactor by 1st Example of this invention, (a) A figure shows a water supply part nozzle part from the inside of a reactor pressure vessel (A arrow view of (b) figure). FIG. 2B is an elevation view as seen, and FIG. In the outline of a reactor pressure vessel of a reactor to which the present invention is implemented, (a) is a cross section viewed from the height position of the steam separator (A-A arrow in (b)). FIG. 2B is a longitudinal sectional view of a reactor pressure vessel. It is a figure which shows the structure of the water supply nozzle part vicinity of the reactor by a prior art example, (a) figure is the elevation which looked at the water supply part nozzle part from the inner side of the reactor pressure vessel (A arrow view of (b) figure) (B) The figure is a BB sectional view of (a) figure. It is an expanded sectional view of the principal part in the (b) figure of FIG. FIG. 5 is a view showing the structure in the vicinity of the water supply nozzle portion of the reactor according to the second embodiment of the present invention, and FIG. FIG. 2B is an elevation view as seen, and FIG. FIG. 6 is a diagram showing the structure near the water supply nozzle portion of the reactor according to the third embodiment of the present invention, in which FIG. FIG. 2B is an elevation view as seen, and FIG. FIG. 4 is a diagram showing a structure near the water supply nozzle portion of a nuclear reactor according to a fourth embodiment of the present invention. FIG. FIG. 2B is an elevation view as seen, and FIG. FIG. 9 is a view showing the structure in the vicinity of a water supply nozzle portion of a nuclear reactor according to a fifth embodiment of the present invention. FIG. FIG. 2B is an elevation view as seen, and FIG. 1 is a system diagram of a main steam system and a water supply system of a nuclear reactor to which an embodiment of the present invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Water supply nozzle, 2 ... Water injection nozzle, 3 ... Thermal sleeve, 4 ... Shroud head bolt, 5 ... Shroud head bolt ring, 6 ... T-tube, 7 ... High temperature reactor water, 8 ... Low temperature water supply, 9 ... Ring Flow path, 11 ... Reactor pressure vessel, 12 ... Shroud, 13 ... Steam separator, 14 ... Downcomer, 15 ... Recirculation pump, 16 ... Lower plenum, 17 ... Core, 18 ... Steam dryer, 19 ... Main steam Piping, 20 ... high temperature water, 21 ... low temperature water, 22 ... high and low temperature water interface, 23 ... bounce water, 24 ... communication pipe, 25,35 ... header pipe, 26 ... high pressure turbine, 27 ... humidity separator, 28 ... low pressure Turbine, 29 ... Condenser, 30 ... Low pressure feed water heater, 31 ... Feed water pump, 32 ... High pressure feed water heater, 33 ... Extraction flow rate adjustment valve, 34 ... Feed water bypass pipe, 36, 36a, 36b ... Discharge port, 37 ... water pipes.

Claims (6)

A reactor pressure vessel;
A steam system for supplying steam from the reactor pressure vessel to a high-pressure turbine and a low-pressure turbine;
A condenser for condensing steam discharged from the low-pressure turbine into water;
A water supply system that heats the water with a feed water heater and leads it to the reactor pressure vessel through a water supply pipe with a pump;
Disposed at a height below the reactor operating water level in the reactor pressure vessel, a water supply nozzle of the reactor pressure vessel;
A thermal sleeve provided in the water supply nozzle and in communication with the water supply pipe;
A header pipe provided in the reactor pressure vessel and communicating with the thermal sleeve;
A water supply apparatus for a reactor comprising: a water injection nozzle that is disposed at a height lower than the reactor operating water level and communicates with the header pipe to discharge the water into the reactor pressure vessel.
The header pipe is connected with a communication pipe and is equipped in multiple upper and lower stages, and the lower header pipe is equipped with the water injection nozzle,
A water supply device for a nuclear reactor, wherein a central position in a height direction of a discharge port for discharging the water of the water injection nozzle is disposed below a central position in the height direction of the thermal sleeve.   The water supply apparatus for a reactor according to claim 1, wherein the highest position of the discharge port is disposed below a height position of a lower inner wall surface of the water supply nozzle.   3. The reactor water supply apparatus according to claim 1, wherein the direction of the discharge port is a horizontal direction toward the center of the reactor pressure vessel, a diagonally downward direction toward the center of the reactor pressure vessel, or a downward direction.   3. The water injection nozzle according to claim 1, wherein the water injection nozzle is provided with a plurality of discharge ports, and a discharge direction of at least one of the plurality of discharge ports is horizontal toward the reactor pressure vessel center. Direction, or a diagonally downward direction toward the center of the reactor pressure vessel, or a downward direction, and the direction of at least one other discharge port among the discharge ports A reactor water supply device having a direction other than the one of the directions. 5. The reactor according to claim 1, wherein the nuclear reactor has increased the rated heat output of the reactor at the beginning of the construction of the reactor beyond the original rated heat output after the construction. A water supply system for a nuclear reactor, which is a nuclear reactor whose power has been improved. 6. The water supply system according to claim 5, wherein the water supply system lowers the temperature of the water at the inlet of the water supply nozzle by 1 ° C. or more from the temperature at the rated operation at the time of initial construction of the reactor. A water supply system for a nuclear reactor, which is a water supply system that leads toward the reactor.

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