JP2007225461A - Output control method of nuclear reactor and nuclear reactor plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a period at a reactor start time for increasing reactor output up to a rated output in a natural circulation boiling water reactor. <P>SOLUTION: A feed water control device controls the first temperature of feed water to be supplied to the reactor to become higher than the second temperature of the feed water to be supplied to the reactor at a rated output time in a partial period at the reactor start time for raising the reactor output up to the rated output. The reactor output can be raised also by extracting control rods from the core at the reactor start time. The feed water control device lowers the first temperature to the second temperature after stopping extraction operation of the control rods at the reactor start time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reactor power control method and a reactor plant, and more particularly to a reactor power control method and a reactor plant suitable for application to a natural circulation boiling water reactor.

  In a conventional boiling water nuclear power plant, the reactor power is controlled by a control rod and a core flow rate. The control rod contains a material having a high neutron absorption capability such as boron. A control rod is inserted into a core loaded with a plurality of fuel assemblies containing fissile material such as uranium, and the control rod is pulled out of the core to change the number of neutrons absorbed by the fuel rod. The output is controlled. The core flow rate control controls the coolant flow rate (core flow rate) flowing into the core by controlling the internal pump installed in the reactor pressure vessel or the recirculation pump installed in the recirculation system piping. By the core flow rate control, the volume ratio (void ratio) of steam and water in the core changes, and the reactor power is controlled. When the amount of steam in the core increases and the proportion of water decreases (the void ratio increases), the reaction of the high energy fast neutrons generated by fission colliding with water molecules (mainly hydrogen atoms) and slowing down decreases, and thermal neutrons The number decreases. The probability of a fission reaction with uranium is higher for thermal neutrons than for fast neutrons in ordinary light water reactors (eg, boiling water reactors). For this reason, when the void ratio of the core increases, the reactor power decreases. If the core flow rate is decreased, the void ratio increases. Conversely, if the core flow rate is increased, the void ratio decreases. Therefore, the reactor power can be controlled by controlling the core flow rate.

  The neutron reaction rate (hereinafter referred to as reactivity) that can be controlled by the control rod is greater than the reactivity that can be controlled by core flow rate control. However, since the control rod control changes the reactivity of the local position of the core where the control rod is moved, the power distribution in the core radial direction and the axial direction changes relatively greatly before and after the control rod operation. On the other hand, in the core flow rate control, since the change in the void ratio reaches the entire core, the change in the power distribution in the radial direction and the axial direction of the core is relatively small. Using this characteristic, at the start of the boiling water reactor, the reactor power is controlled by the control rod until the reactor thermal power reaches approximately 70% of the rated power. Reactor power is controlled by control. Specifically, the reactor power is increased by increasing the core flow rate and decreasing the core void ratio. In the region where the reactor power is high, margins for thermal constraints such as the limit power and maximum linear power density are reduced, so by using the core flow control with little change in the power distribution shape, it is safe and fast. There is an advantage that the reactor power can be increased to the rated power (100% nuclear power).

  As another method for controlling the reactor power, there is a method described in Patent Document 1 for controlling the temperature of the coolant supplied to the reactor (feed water temperature). Specifically, the feed water temperature is adjusted by the feed water temperature control device to control the reactor output.

Japanese Patent Laid-Open No. 62-138794

  As a highly economical nuclear reactor, a natural circulation boiling water reactor has been developed that cools the core with a natural circulation coolant. Equipment such as a recirculation pump and an internal pump, and a control device for controlling the equipment are unnecessary, and a compact nuclear reactor can be realized. By the way, considering the start-up operation of a natural circulation boiling water reactor, the core flow rate control that was performed in the conventional forced circulation boiling water reactor cannot be performed. Will do. In control rod operation, the power distribution changes in the core radial direction and axial direction are relatively large, and the accumulation of xenon and samarium, which suppresses the output in the high output region during startup, is small, so the power in the core radial direction and axial direction during startup Peaking may be larger than at rated output. As a result, there is a possibility that the control rod cannot be operated during the start-up due to thermal constraints such as limit output and maximum line output density. In such a case, it is necessary to stop and wait for the control rod operation until xenon and samarium accumulate and the output peaking decreases, or change the extraction procedure so that the output peaking does not become excessive by changing the control rod extraction procedure. There is. In any case, since the start-up operation is once stopped, there is a problem that the reactor start-up time increases and the operation rate of the reactor decreases.

  An object of the present invention is to provide a reactor power control method and a reactor plant capable of shortening a period during which the reactor power is increased to a set power.

  In order to achieve the above object, a feature of the present invention is that the first temperature of the feed water supplied to the reactor is set at the set output at a part of the period when the reactor is started to increase the reactor output to the set output. The purpose is to control the feed water supplied to the nuclear reactor to be higher than the second temperature. By such control, it is possible to shorten the period at the time of starting the reactor in which the reactor power is increased to the set power (for example, the rated power).

  Preferably, the first temperature of the water supply is lowered to the second temperature as it approaches the set output. In addition, by applying the above-described characteristic feed water temperature control to a natural circulation reactor, the period of startup of the natural circulation reactor can be shortened.

  ADVANTAGE OF THE INVENTION According to this invention, the period at the time of starting to raise a reactor output to setting power can be shortened.

Examples of the present invention will be described below.
Example 1
A natural circulation boiling water reactor power generation system equipped with a reactor power control apparatus according to a preferred embodiment of the present invention will be described with reference to FIG.

  The natural circulation boiling water reactor power generation system includes a nuclear reactor 1, a high pressure turbine 14, a low pressure turbine 15, a condenser 17 and a generator 16. A reactor core 2 loaded with a large number of fuel assemblies is provided in the nuclear reactor 1. The reactor power is controlled by inserting a control rod 4 containing a neutron absorber into the core 2 or withdrawing the control rod 4 from the core 2. The control rod 4 is moved in the height direction of the core 2 by a control rod drive device 5 having an electric motor (or a hydraulic drive mechanism).

A main steam pipe 10 connected to the upper part of the nuclear reactor 1 is connected to a high pressure turbine 14 and a low pressure turbine 15. The steam generated in the core 2 is guided to the high-pressure turbine 14 and the low-pressure turbine 15 through the main steam pipe 10 to rotate these turbines. The generator is rotated by the rotation of these turbines to generate power. Steam discharged from the low-pressure turbine 15 is condensed into water by seawater flowing in the heat transfer pipe in the condenser 17. The condensed water discharged from the condenser 17 is heated by the low-pressure feed water heater 18, boosted by the feed water pump 19, heated by the high-pressure feed water heater 20, and then returned to the reactor 1 through the feed water pipe 23. It is. A turbine steam flow rate adjusting valve 12, which is an electric valve, is installed in the main steam pipe 10, and a turbine bypass valve 27, which is an electric valve, is installed in the extraction pipe 25 connected to the main steam pipe 10. The flow rate of steam supplied to the turbines 14 and 15 can be controlled by adjusting the opening degree of these valves. The steam that has passed through the turbine bypass valve 27 is guided to the extraction pipe 25 and the steam extracted by the high-pressure turbine 14 is guided to the low-pressure feed water heater 18 through the extraction pipe 26 to heat the feed water. Those steams that heated the feed water are condensed into water by the condenser 17. The main steam pipe 10 is provided with a pressure detector 21 and a steam flow detector 13 for detecting the steam pressure and the steam flow used for controlling the reactor pressure and the generator output. Further, in this embodiment, an extraction flow rate adjustment valve (electric valve) 11 as a means for controlling the feed water temperature is installed in an extraction pipe 24 connected to the main steam pipe 10. The steam extracted from the main steam pipe 10 and passing through the extraction flow rate adjusting valve 11 is guided to the high-pressure feed water heater 20 to heat the feed water. A temperature measuring device 22 is installed in the water supply pipe 23.

  The reactor power control device of this embodiment includes a power control device 40, a feed water temperature control device 31, a turbine control device 30, and a control rod drive control device 6. The output control device 40 includes a switch, a keyboard, a touch panel, and the like, and includes an input unit 41 through which an operator can input instruction information, and an output unit 44 including a meter and a display device that display information to the operator. The output unit 44 further has an interface for outputting information to an electronic recording medium such as a hard disk. The output control device 40 is connected to the control rod drive control device 6, the turbine control device 30 and the feed water temperature control device 31.

From the output control device 40 to the control rod drive control device 6, a control rod operation start command 45 including positional information of the control rod in the radial direction of the core to be operated and control rod insertion information (or control rod extraction information) is received. Reportedly. The control rod drive control device 6 that has received the control rod operation start command 45 drives the corresponding control drive device 5 at the designated position among the plurality of control rod drive devices 5 in accordance with the control rod operation procedure that has been input in advance. Thus, the control rod 4 is operated. Control rod insertion position information 47 is input from the control rod drive device 5 to the control rod drive control device 6. The control rod drive control device 6 transmits an operation completion signal 48 indicating that the operation of the instructed control rod is completed to the output control device 40. Further, when the control rod drive control device 6 cannot be operated for some reason, the control rod drive control device 6 transmits a signal indicating that to the output control device 40.

  The output control device 40 inputs a load set value 60 to the turbine control device 30. The turbine control device 30 to which the load set value 60 has been input has the measured generator output measurement value 63, the pressure signal 62 measured by the pressure detector 21, the respective opening degrees of the turbine steam flow rate adjustment valve 12 and the turbine bypass valve 27. Based on the information 61, each opening degree of the turbine steam flow rate adjusting valve 12 and the turbine bypass valve 27 is controlled.

The output control device 40 outputs a feed water temperature target value (or feed water temperature set value) 50 to the feed water temperature control device 31. The feed water temperature control device 31 inputs the feed water temperature measurement value 52 measured by the temperature measuring device 22, and bleeds based on the bleed flow rate valve opening signal 51 obtained based on the feed water temperature measurement value 52 and the feed water temperature target value 50. The opening degree of the flow rate adjusting valve 11 is adjusted. The feed water temperature is controlled by adjusting the opening degree. The feed water temperature control device 31 transmits the feed water temperature information 53 to the output control device 40.

  Specific configurations of the output control device 40, the feed water temperature control device 31, the turbine control device 30, and the control rod drive control device 6 will be described with reference to FIG. The output control device 40 can set a manual control mode in which the reactor is operated by an operator's operation, and an automatic control mode in which the reactor is automatically controlled by controlling the control device when the operation state target value is set. The output control device 40 includes a turbine control device 30 that adjusts the turbine flow rate adjustment valve opening and the turbine bypass valve opening according to the load setting, a control rod drive control device 6 that performs extraction / insertion of the control rod, and a feed water temperature. The control command and the control information can be output independently for each of the feed water temperature control devices 31 that control the control.

The turbine control device 30 adjusts the valve opening degree of the turbine flow rate adjustment valve 12 and the valve opening degree of the turbine bypass valve 27 according to the load setting. In the region where the turbines 14 and 15 do not operate and the generator 16 does not output an electrical output, the turbine control device 30 does not function. When the manual mode is selected in the region where the generator 16 outputs electric output, the output control device 40 inputs the generator load to the turbine control device 30. The turbine control device 30 adjusts the opening of the turbine flow rate adjustment valve 12 and the opening of the turbine bypass valve 27 so that the generator output corresponds to the load set value. Control equipment and logic for adjusting the opening of the turbine flow rate adjustment valve 12 and the opening of the turbine bypass valve 27 according to the load set value 60 and the reactor pressure are incorporated in the turbine control device 30. In the automatic mode, not only a constant value but also a generator load set value that changes with time can be input, and control that follows a load set value that changes with time such as load following operation becomes possible.

  The control rod drive control device 6 can handle three control modes: manual, semi-automatic, and automatic. These control modes can be set from the output control device 40. In the manual control mode, the operator selects an operation control rod at the input unit 41 and presses a control rod extraction (or insertion) switch provided at the input unit 41. A control rod operation command generated by the output control device 40 based on this operation is input to the control rod drive control device 6 and the control rod operation monitoring system 33. The control rod operation monitoring system 33 determines whether the selected control rod matches the control rod operation sequence input in advance, the thermal limit value may not be exceeded after the control rod operation, or the neutron flux or the reactor period is limited. Judges whether the value is exceeded. The control rod operation monitoring system 33 outputs information indicating the determination result to the control rod drive control device 6 when any of the determination results is “not satisfying the criterion”. In this case, the control rod drive control device 6 does not perform the control rod operation based on the control rod operation command output from the output control device 40.

  The semi-automatic control mode is the same as the above-described manual control mode except that the control rod drive control device 6 automatically selects a control rod to be operated based on a control rod operation sequence. In the automatic control mode, the control rod drive control device 6 automatically sets the operation control rod and the control rod operation timing so as to reach the target based on the control rod automatic control logic incorporated in the output control device 40. Determine and operate the control rod. At this time, as in manual control and semi-automatic control, the control rod operation monitoring system 33 monitors the control rod operation. The control rod operation monitoring system 33 outputs a control rod operation stop signal to the control rod drive control device 6 when determining that “the standard is not satisfied”. A reactor state monitoring system 34 including a neutron flux detector and a process computer is connected to the output control device 40. The reactor state monitoring system 34 has a function of switching the control rod drive control device 6 from the automatic control mode to the manual control mode when the control rod drive control device 6 determines that the automatic mode control is inappropriate.

  As shown in FIG. 2, the feed water temperature control device 31 and the turbine control device 30 have control modes of a manual control mode and an automatic control mode, and also have a function of turning off these control modes.

  In the prior art, the feed water temperature is not controlled when the reactor is started, but this is the same as when the function of the feed water temperature control device 31 in this embodiment is turned off. When the function of the feed water temperature control device 31 is turned off, the feed water supplied to the nuclear reactor 1 is heated by the feed water heater based on the turbine flow rate and the turbine bypass flow rate controlled by the turbine control device 30, and is obtained from the heat balance. It becomes temperature.

  FIG. 3 shows an example of the control logic of the feed water temperature control device 31. The feed water temperature control device 31 includes a lead compensation circuit 92, an adder 93, an upper / lower limiter 94, a lead / lag compensation circuit 95, a converter 96, and an upper / lower limiter 94. A feed water temperature set value (target value) is input from the input unit 41 to the output control device 40. The output control device 40 outputs the feed water temperature target value 50 to the feed water temperature control device 31. The feed water temperature control device 31 inputs the feed water temperature measurement value 52 measured by the temperature measuring device 22. The feed water temperature control device 31 obtains a deviation signal between the signal obtained by compensating the measured water delay time for the feed water temperature measured value 52 by the advance compensation circuit 92 and the feed water temperature target value 50 by the adder 93. This deviation signal passes through the upper / lower limiter 94, is compensated by the advance / lag compensation circuit 95, and is converted into the extraction flow control valve opening signal 98 by the converter 96. Based on the extraction flow control valve opening signal 98, the opening of the extraction flow adjustment valve 11 is controlled. In the case of manual control, the water supply temperature target value 50 is input from the input unit 41 by the operator and set in the output control device 40. In the case of automatic control, the output control device 40 calculates and obtains a feed water temperature target value 50 corresponding to the target generator output by using the built-in feed water temperature control logic, and this feed water temperature target value 50 is calculated. Output to the device 31. In the case of automatic control, the output control device 40 outputs the feed water temperature target value 50 obtained by calculation to the output unit 43. This target water supply temperature value 50 is displayed on the display device of the output unit 43. At the time of manual control, the operator can input the feed water temperature target value with reference to the feed water temperature target value 50 at the time of automatic control. In this embodiment, when such feed water temperature control is performed, the output control device 40 uses the feed water temperature as an index, and further controls the reactor output with the same index (feed water temperature target value) by manual control and automatic control. Therefore, for example, the operator can easily operate the natural circulation furnace rather than using the extraction flow rate adjustment valve opening as an index.

  The feed water temperature control at the time of reactor activation in the present embodiment will be described with reference to FIG. In FIG. 4, the horizontal axis is the main steam flow rate (%) generated in the reactor 1 and substantially corresponds to the reactor power (%), and the vertical axis is the standard feed water temperature based on the feed water temperature at the rated output. is there. The saturation temperature of the rated pressure (about 7 MPa) of the boiling water reactor is about 287 ° C., and the feed water temperature at the rated output varies from plant to plant, but is about 180 to 220 ° C. Reactor start-up is the operation of the reactor that raises the reactor power from 0% to 100% (rated power).

  A dotted line 80 passing through the points a, b, c, and d shows the general characteristics of the main steam flow rate and the feed water temperature at the time of conventional startup where the feed water temperature control determined from the heat balance is not performed. In the generator output control region in which the generator generates electrical output, the feed water temperature increases as the main steam flow rate increases, that is, the reactor output increases. Therefore, if the reactor power is increased at the time of start-up, the feed water temperature changes from point a → point b → point c → point d and reaches the maximum temperature at the rated output. On the other hand, in this embodiment, the temperature of the feed water at the time of starting up the reactor is controlled as indicated by the solid line 81 passing through points a, e, f, g, and d, and the generator output region (output of about 85) is controlled by the control rod. %), The feed water temperature is controlled to be higher than the feed water temperature at the rated output and below the saturation temperature. After the point g, the operation of the control rod is stopped, and the reactor power can be increased by lowering the feed water temperature and decreasing the void ratio of the core. When the feedwater temperature control is performed at the time of reactor startup, the void ratio of the entire core changes as in the core flow rate control.Therefore, when the output is increased unlike the control rod control, the local radial output distribution and axial output Little change in distribution. As a result, control rod operation can no longer be disabled during start-up due to limitations such as limit power and maximum linear power density that are a concern during control rod operation, and the reactor start-up time can be shortened and the operating rate can be improved.

  In conventional forced circulation boiling water reactors, if the feed water temperature is increased, cavitation tends to occur in the recirculation pump and internal pump rotor blades, which may reduce pump efficiency and impair the rotor blade soundness. there were. Since the natural circulation boiling water reactor does not have forced circulation equipment such as a recirculation pump and an internal pump, the feed water temperature can be controlled to be high without being restricted by the cavitation restrictions.

  In the above-described example of this embodiment, the feed water temperature is controlled from the initial stage of the generator output control region (point a: reactor output of about 10%). In this embodiment, at the points a, b, c, f, g, and d. A feed water temperature control such as the line 82 shown is also possible. In this feed water temperature control, the feed water temperature control is turned off until the middle of the control rod operation (point c) in the generator output control, the control rod operation is temporarily stopped at the point c, and the feed water temperature control is performed to increase the feed water temperature. (Point f), the control rod operation is started again to reach point g. From point g, the control rod operation is stopped and the feed water temperature is lowered to reach the rated output (point d). Thus, in this embodiment, the feed water temperature control can be performed independently of the control rod control, and the reactor power can be controlled.

When the automatic control mode is set, the output control device 40 outputs the feed water temperature target value 50 indicated by the solid line 81 passing through the points a, e, f, g, and d to the feed water temperature control device 31. When the reactor is started up, the feed water temperature control device 31 uses the extraction flow control valve opening signal 98 created based on the feed water temperature target value 50 and the feed water temperature measurement value 52 shown in FIG. 11 is controlled. Thereby, the feed water temperature at the time of reactor start-up changes as point a → point e → point f → point g → point d. Further, when the manual control mode is set based on the input information from the input unit 41, the output control device 40 has points a, b, c, f, g, and d (solid lines) input by the operator from the input unit 41. 82), the water supply temperature target value 50 is output to the water supply temperature control device 31. Thereby, the feed water temperature control shown by the line 82 is realizable. The output control device 40 stores the target water supply temperature value indicated by the points a, e, f, g, and d of the solid line 81 (or the points a, b, and the solid line 82) in the memory (not shown) of the output control device 40. c), f, g, d) are stored, and when the automatic control mode is set, these water supply temperature target values 50 are read from the memory and output to the water supply temperature control device 31. You may make it do.

  An example of the configuration of the manual control mode and the automatic control mode of the reactor power control incorporated in the power control device 40 will be described with reference to FIG. The generator output is controlled by the turbine controller, while the reactor output control is performed by controlling the control rod and the feed water temperature. The manual control mode includes a control rod control mode and a feed water temperature control mode, and the operator can select these control modes from the input unit 41. When the control rod control mode is selected in the manual control mode, the operator inputs information on the operation control rod position and the operation timing from the input unit 41 to the output control device 40. The control rod drive control device 6 operates the corresponding control rod based on the information from the output control device 40. In the manual control mode, when the feed water temperature control mode is selected, the operator inputs the feed water temperature target value to the output control device 40 from the input unit 41. The feed water temperature control device 31 performs feed water temperature control from the output control device 40 based on the target value.

  The automatic control mode of reactor power control in the power control device 40 includes six modes having different functions as shown in FIG. The critical control mode is a mode in which the control rod drive control device 6 automatically performs the control rod pull-out operation from the control rod full insertion state to the criticality based on a command from the output control device 40. The control rod is operated so that the reactor period is below the allowable value. The reactor power in this mode is very low. The temperature increase / pressurization control mode is a mode in which the control rod drive control device 6 automatically performs a control rod pull-out operation from criticality to reaching the rated pressure based on a command from the output control device 40. The control rod is pulled out so that the reactor water temperature change rate matches the target change rate. The reactor power in that mode is usually less than 3% of the rated power. The reactor power control mode is a mode in which the control rod drive control device 6 increases the reactor output until the rated pressure is reached after the control rod 4 is pulled out based on a command from the power control device 40 until the rated pressure is reached. is there. The control rod 4 is pulled out so that the reactor heat output change rate matches the target value. The reactor power in this mode is about 10% or less of the rated power. The generator output control rod control mode is a mode in which the control rod drive controller 6 pulls out the control rod 4 so that the generator output change rate coincides with the target value after the generator is inserted. The subcritical control mode is a mode in which the control rod 4 is inserted from the output operation state by the control rod drive control device 6 to make the nuclear reactor subcritical. In all of the above modes, the reactor power is controlled by control rod operation.

  The generator output feed water temperature control mode is a mode in which the reactor output is automatically controlled by feed water temperature control based on the generator output measurement value 63. One of the features of this embodiment is that the output control device 40 has a generator output feed water temperature control mode. Since the feed water temperature control device 31 and the control rod drive control device 6 function independently of each other, for example, when the control rod operation is performed in the automatic control mode, the feed water temperature control can be performed in the manual mode.

FIG. 6 shows an example of logic for creating the feed water temperature target value 50 used in the feed water temperature control device 31 in the above-described generator output feed water temperature control mode based on the generator output target value 100 and the generator output measurement value 63. It explains using. This logic is incorporated in the output control device 40. As shown in FIG. 6, the output control device 40 is configured to create a feed water temperature target value 50 in the generator output feed water temperature control mode, as shown in FIG. 6, an adder 102, an upper / lower limiter 103, a proportional circuit 104, an integration circuit 105, A converter 106 and an upper / lower limiter 107 are provided. The output control device 40 obtains a deviation signal between the generator output target value 100 and the generator output measurement value 101 by the adder 102. This deviation signal passes through the upper and lower limiter 103 and is input to the proportional circuit 104 and the integration circuit 105, respectively. Based on the output signals of the proportional circuit 104 and the integrating circuit 105, the converter 106 creates a target water supply temperature value 50. The feed water temperature control device 31 performs feed water temperature control in the generator output feed water temperature control mode using the feed water temperature target value 50. By incorporating the control logic of FIG. 6 into the output control device 40, the same feed water temperature control device 31 can perform the feed water temperature control in both the manual control mode and the automatic control mode. In addition, in both the control rod control mode and the feed water temperature control mode, the control index is the same when controlling the reactor output manually and when controlling it automatically, so that the operator can easily operate the reactor. Have.

  According to the present embodiment, the first temperature of the feed water supplied to the reactor 1 (for example, points e, f, and so on) during a part of the period when the reactor is started to increase the reactor power to the rated power (set power). The feed water temperature at g) is controlled to be higher than the second temperature of the feed water supplied to the reactor 1 at the rated output (for example, the feed water temperature at the point d). The period at which the reactor is started up to increase the output can be shortened. In particular, in the natural circulation boiling water reactor, the pump for supplying the coolant to the core 2 is not provided, so that the feed water temperature can be controlled high.

  Further, in this embodiment, after the control rod operation is stopped at the time of starting up the reactor, the first temperature of the feed water is decreased to the second temperature, so that the temperature in the core 2 is reduced due to the temperature drop of the feed water supplied to the reactor 1. The void collapses and the reactor power can be increased.

According to the present invention, as a function of an output control device of a nuclear power plant, by providing a means for controlling a feed water temperature by inputting a feed water temperature target value, a natural circulation boiling water reactor can be started in a short time. Can improve economy. In the method of the present invention in which the feed water temperature target value is input from the output control device, the control index is the same when manually controlling the reactor output and when controlling the reactor automatically, so that the operator can easily operate the reactor. Has advantages.
(Example 2)
Although the above embodiment is directed to a natural circulation boiling water reactor, the present invention can also be applied to a forced circulation boiling water reactor.

  A forced circulation boiling water reactor power generation system equipped with a reactor power control apparatus according to another embodiment of the present invention will be described with reference to FIG. In this embodiment, the same components as those in the embodiment shown in FIG. The forced circulation boiling water reactor power generation system is different from the natural circulation boiling water reactor power generation system shown in FIG. 1 in that an internal pump 70 for forcibly circulating coolant in the nuclear reactor 1 is provided. The reactor power control apparatus of the present embodiment has a configuration in which a core flow rate control device 71 that controls the rotational speed of the internal pump 70 is added to the reactor power control device shown in FIG. By controlling the rotational speed of the internal pump 70, the core flow rate supplied to the core 2 can be controlled. The reactor power control device also includes a power control device 40, a control rod drive control device 6, a turbine control device 30, and a feed water temperature control device 31. The core flow rate control device 71 is connected to the output control device 40.

  The output control device 40 is input with the classification information of the manual control mode and the automatic control mode and the core flow rate setting value 72 from the input unit 41. The output control device 40 outputs the core flow rate setting value 72 to the core flow rate control device 71. The core flow rate control device 71 controls the rotational speed of the internal pump 70 based on the core flow rate setting value 72.

  In the present embodiment, control rod control and recirculation flow rate control are used for reactor power control when the reactor is started. At the time of starting the reactor, the feed water temperature control device 31 is OFF. The feed water temperature control device 31 is used for compensation of combustion reactivity. When the nuclear reactor undergoes burning of fissile material, the reactivity decreases, and it is necessary to withdraw the control rod 4 or reduce the core void ratio to compensate for the decreased reactivity. In this embodiment, the combustion reactivity is compensated by the control of the core flow rate control device 71 and the feed water temperature control device 31. Specifically, the core flow rate controller 71 increases the core flow rate, and the feed water temperature controller 31 lowers the feed water temperature from that during normal operation. At this time, the feed water temperature control device 31 inputs the feed water temperature target value from the output control device 40, and controls the opening degree of the extraction flow control valve 11 so as to realize this feed water temperature target value. By this control, the reactor power is controlled.

  An example of the manual control mode and the automatic control mode of the reactor power control incorporated in the power control apparatus 40 provided in the present embodiment will be described with reference to FIG. These control modes are obtained by adding a core flow rate control mode as a manual control mode and a generator output flow rate control mode as an automatic output control mode to the control mode shown in FIG. 5 in the embodiment of FIG. Since the control rod, feed water temperature, and core flow rate are controlled by independent control devices, they can be controlled independently.

  In this embodiment, since the reactivity control during the operation period after the start operation is performed by the core flow rate control and the feed water temperature control, the control rod operation is reduced or unnecessary, and the fuel economy can be improved. Even when control rod operation is performed, the reactivity that can be controlled by combining the core flow rate control and the feed water temperature control is increased, fuel removal is increased, and the reactor power is increased to increase the fuel output. Economic efficiency can be improved. This power control device also has the advantage that it is easy for the operator to operate the reactor because the control indices for controlling the reactor power manually and automatically are the same.

  In the present embodiment, similar to the above-described embodiment, it is possible to shorten the period at the time of starting the reactor in which the reactor power is increased to the rated power. Further, in the present embodiment, the first temperature of the feed water is set to be higher than the second temperature of the feed water in a part of the period when the reactor is started to raise the reactor power to the rated power with respect to the forced circulation boiling water reactor. Therefore, the fuel economy can be improved by reducing or eliminating control rod control during the operation period.

1 is a configuration diagram of a natural circulation boiling water reactor power generation system including a reactor power control apparatus according to a preferred embodiment of the present invention. FIG. It is a block diagram of the reactor power control apparatus shown in FIG. It is explanatory drawing which shows an example of the control logic of the feed water temperature control apparatus shown in FIG. It is explanatory drawing which shows feed water temperature control at the time of the reactor start-up by the reactor power control apparatus shown in FIG. It is explanatory drawing which shows the specific example of the manual control mode and automatic control mode of the output control apparatus shown in FIG. It is explanatory drawing which shows an example of the control logic which produces the feed water temperature target value in generator output feed water temperature control mode by one of the control logics used by the output control apparatus shown in FIG. It is a block diagram of the forced circulation type boiling water reactor power generation system containing the reactor power control apparatus which is another Example of this invention. It is explanatory drawing which shows the specific example of the manual control mode of the output control apparatus shown in FIG. 7, and automatic control mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reactor, 2 ... Core, 3 ... Neutron flux detector, 4 ... Control rod, 5 ... Control rod drive device, 6 ... Control rod drive control device, 10 ... Main steam piping, 11 ... Extraction flow adjustment valve, 12 DESCRIPTION OF SYMBOLS ... Turbine steam flow control valve, 13 ... Steam flow detector, 14 ... High pressure turbine, 15 ... Low pressure turbine, 16 ... Generator, 17 ... Condenser, 18 ... Low pressure feed water heater, 20 ... High pressure feed water heater, 21 DESCRIPTION OF SYMBOLS ... Pressure detector, 22 ... Temperature measuring device, 23 ... Feed water piping, 24-26 ... Extraction pipe, 27 ... Turbine bypass valve, 30 ... Turbine control device, 31 ... Feed water temperature control device, 40 ... Output control device, 41 ... Input unit 43 ... Output unit 45 ... Control rod operation start command, 48 ... Operation completion signal, 50 ... Water supply temperature control target value, 51 ... Bleed flow rate valve opening signal, 52 ... Water supply temperature measurement value, 53 ... Water supply temperature information,
60 ... Load set value, 61 ... Opening information, main steam flow control valve opening signal and flow signal, 62 ... pressure signal, 63 ... generator output measurement value, 70 ... internal pump, 71 ... core flow control device, 72: Core flow rate set value.

Claims (16)

  The first temperature of the feed water to be supplied to the reactor is set to be higher than the second temperature of the feed water to be supplied to the reactor at the set output in a part of the period when the reactor is started to increase the reactor power to the set power. Reactor power control method to control so that it becomes higher.   The first temperature of the feed water supplied to the reactor during the partial period of the generator output control period in which the electric power is generated by the generator at the time of starting the reactor to raise the reactor output to the set output is the set output. A reactor power control method for controlling the water supply temperature to be higher than a second temperature of the feed water supplied to the reactor.   3. The first temperature is decreased to the second temperature after the control rod pulling operation is stopped after the control rod pulling operation is stopped together with the control output increase control by the control rod pulling operation at the time of starting the reactor. The reactor power control method described in 1.   A set temperature of the first temperature is set based on an electric output measurement value of a generator connected to a turbine rotated by steam generated in the nuclear reactor, and the first temperature becomes the set value. The reactor power control method according to any one of claims 1 to 3, wherein adjustment is performed.   The reactor power control method according to any one of claims 1 to 4, wherein the set output is a rated output of the reactor.   The first temperature is controlled by controlling the amount of the steam supplied to the feed water heater that is extracted from the steam generated in the reactor and heated to the feed water heater that is fed to the feed water heater that heats the feed water. The method for controlling the output of a nuclear reactor according to any one of claims 1 to 5, wherein the method is performed by controlling.   The nuclear reactor power control method according to any one of claims 1 to 6, wherein the nuclear reactor is a natural circulation nuclear reactor. A feed water temperature detecting means for detecting the temperature of the feed water supplied to the nuclear reactor, a heating means for heating the feed water, and a feed water temperature control device for controlling the temperature of the feed water heated by the feed water heating means,
The feed water temperature control device supplies a first temperature of the feed water to the reactor at the set output in a part of the period when the reactor is started to increase the reactor output to the set output. A reactor plant, wherein the heating amount of the feed water by the feed water heating means is controlled to be higher than two temperatures. Feed water temperature detecting means for detecting the temperature of feed water supplied to the nuclear reactor, heating means for heating the feed water, feed water temperature control device for controlling the temperature of the feed water heated by the feed water heating means, and output control With the device,
In a part of the generator output control period in which the feedwater temperature control device starts up the reactor output to raise the reactor output to the set output and generates an electrical output in the generator, the first temperature of the feedwater is A reactor plant, wherein a heating amount of the feed water by the feed water heating means is controlled so as to be higher than a second temperature of the feed water supplied to the reactor at the set output. A control rod control device that controls the operation of the control rod provided in the nuclear reactor, and an output control device that outputs a control command of the control rod to the control rod control device,
The said feed water temperature control apparatus reduces the said 1st temperature to the said 2nd temperature based on the completion signal of the said control rod extraction operation at the time of the said reactor start input from the said output control apparatus, or The nuclear reactor plant according to claim 9. An output control device configured to set the set temperature of the first temperature based on an electric output measurement value of a generator connected to a turbine rotated by steam generated in the reactor;
The nuclear power plant according to claim 8 or 9, wherein the feed water temperature control device adjusts the first temperature to be the set value. The output control device determines a set temperature of the first temperature based on an electrical output measurement value of a generator connected to a turbine rotated by steam generated in the reactor;
The nuclear power plant according to claim 10, wherein the feed water temperature control device adjusts the first temperature to be the determined set temperature.   The nuclear power plant according to any one of claims 8 to 12, wherein the set output is a rated output of the nuclear reactor. A feed water heater that heats feed water, which is the feed water heating means, and an extraction pipe that is connected to a main steam pipe connected to the nuclear reactor and extracts steam extracted from the main steam pipe to the feed water heater, Steam flow rate adjusting means provided in the extraction pipe,
The nuclear power plant according to any one of claims 8 to 13, wherein the feed water temperature control device controls the first temperature by controlling the steam flow rate adjusting means.   The nuclear reactor plant according to any one of claims 8 to 14, wherein the nuclear reactor is a natural circulation nuclear reactor. The output control device determines a set temperature of the first temperature based on a generator output target value;
The nuclear power plant according to claim 9, wherein the feed water temperature control device adjusts the first temperature to be the determined set temperature.

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