JPS5928697A - Power control device of bwr type reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is applicable to the case where the load side and the nuclear reactor are isolated [Output of two reactors? [Technical Background of the Invention] A boiling water reactor houses a C core in a reactor pressure vessel, and a cooling material (light water) in this reactor pressure vessel is used. is configured to be circulated through the core by a coolant circulation pump. This coolant is then heated and boiled inside the reactor core.

This two-phase flow of water and water flows above the core as a two-phase flow of steam and water.Then, this two-phase flow of water and steam is separated into water and steam by a steam separator, and the separated steam is transferred to the main steam pipe. The separated water is sent to the load side C1 of the turbine etc. via the coolant circulation pump. It is condensed in a condenser and returned to the reactor pressure vessel by a feed water pump.

Is the above coolant a moderator? If the output of the core increases for some reason, the proportion of steam in the core, that is, the void ratio, will be affected, and the number of coolant, or moderator, in the core will decrease, so neutrons will The speed of perception decreases and the way it comes out decreases.

Conversely, if the core output decreases for some reason, the void ratio decreases and the core protrusion increases. Therefore, in a boiling water reactor, voids in the core reduce the output to a predetermined value (0). Also.

If the /+it amount T of h waste material flowing through the reactor core, that is, the core flow rate 2, is increased, the void ratio in the reactor core will decrease, and the output will increase,
Well, constant core flow rate? If it is made smaller, the void ratio in the core will increase and the output will decrease. Therefore, to reduce the core flow rate to 2 C
Therefore, the price can be reduced by two outputs.

By the way, if a failure occurs on the load side of such a boiling water nuclear reactor, such as the turbine, the turbine stop valve located in the middle of the main steam pipe is closed.

The main steam supply is stopped L, the turbine operation is stopped, and in this case, the steam generated in the reactor is released to the condenser C1 via the turbine bypass pipe, and the main steam safety relief valve is opened. Excess steam is released into the pressure suppression chamber, and further (
Insert all control rods into the second core and scram the reactor.

A backup power control device is provided in case the scram fails. This power control device compares the reactor pressure with a predetermined pressure setting.

Coolant circulation pump if reactor pressure exceeds this pressure setpoint? Therefore, if the reactor fails to scram when the turbine stop valve is closed and the reactor is isolated from the load side of the turbine, the output of the reactor core will not decrease and steam will not be generated. continues, the reactor pressure rises, and this reactor pressure reaches the above pressure setting value?
If it exceeds this, the coolant circulation pump will stop.□Therefore, the core flow rate will drop significantly, which will increase the void ratio in the core and reduce the core output. In addition, a poison injection device is provided as a secondary reactor shutdown device. This poison injection device injects neutron absorbing substances such as boric acid into the reactor pressure vessel.

It absorbs neutrons and stops nuclear reactions.

[Problems with background technology]

The pressure setting value of the above-mentioned output control device is set to a pressure that is sufficiently higher than the reactor pressure during rated operation to prevent malfunction. Therefore, when the reactor is operating at low output, the pressure between the reactor and the load side is If the reactor is isolated and scram fails, the reactor pressure may not rise to the pressure set value above, and the above output control device may not operate and the operation of the coolant circulation pump may not be stopped. .

In such a case (2), the steam generated in the reactor core continues to be transferred to the pressure suppression chamber ≦ binary through the main steam safety relief valve, and the temperature of the pool water in this pressure suppression chamber rises, causing the pressure suppression chamber to rise. The integrity of walls, etc. (1) There was a possibility of having an adverse effect.To prevent such problems, the pressure setting value can be set low, but in this way, the pressure setting value and the atoms at the rated rotation The difference between the reactor pressure and the reactor pressure decreases, causing problems such as malfunctions.Also, even if such a device is activated and the coolant circulation pump stops, the feed water pump continues to operate and the reactor pressure vessel If subcooled water is supplied inside the reactor core, the void ratio within the reactor core will not increase and the output may not be reduced sufficiently.◎This stipulation states that in such equipment, the coolant circulation pump must be stopped for safety reasons. Tomo C1
Stop the water supply pump and stop the water supply.

Furthermore, it is preferable to operate the poison injection device to inject a poison, that is, a neutron absorbing material into the reactor pressure vessel. but.

With this configuration, in the unlikely event that a malfunction occurs, the water supply will be stopped and the reactor water level will drop significantly by 1 degree.

The emergency core cooling system is activated and the poison injection system is activated. Therefore, once a malfunction occurs, cleaning and other restoration work must be carried out inside the reactor pressure vessel, and the reactor Problems such as a significant drop in the operating rate of the system occur.

[Purpose of the invention]

The present invention has been made based on the above-mentioned situation C2, and its purpose is to ensure that the reactor is in low power operation (2), the reactor and the load side are isolated, and (2) in case of failure To obtain an output control system for a boiling water reactor that operates reliably and does not malfunction (there are two).

[Summary of the invention]

Is the present invention a signal corresponding to the reactor output that corresponds to the reactor output? Input the set value into the output circuit and change the value to the pressure film corresponding to the reactor output (2), output a high pressure set value when the reactor output is high, and lower the pressure when the reactor output is low. Output the set value and use the control circuit to compare this pressure set value with the reactor pressure?
If the reactor pressure exceeds this pressure setting, the coolant circulation pump will be shut down. therefore,
When the reactor output is high, such as during rated power operation of the reactor, the pressure setting value becomes high, and the difference from the reactor pressure during rated operation becomes large. Malfunctions are reliably prevented, and the reactor output is If the pressure is low, the pressure setting value for C2 will be low, so if the reactor is isolated from the load side in such a state and scram fails, the coolant will be reliably supplied even if the rise in reactor pressure is not too large. It is possible to stop the circulation pump and reduce the output of the reactor.

[Embodiments of the invention]

An embodiment of the present invention with reference to the drawings below? explain. In the figure, l is the reactor containment vessel, and reactor pressure vessel 2 is housed in F2 inside this reactor containment vessel ◎And C2, inside this reactor pressure vessel 2, is housed with the reactor core 3. The steam generated in the reactor core 3 passes through the main steam pipe 4, and passes through the main steam stop valve 5. Turbine via main steam control valve 6? (2 is supplied to the turbine 2, which drives the turbine 2, and the turbine 7C2 drives the power generator 1B to generate electricity.The steam that drove the turbine 2 is sent to the condenser 9. Condensed.

Desalination equipment 10. Water is supplied into the reactor pressure vessel 2 by a feed water pump 12 via a feed water heater ll. 16 and 13 are turbine bypass pipes,
A turbine bypass valve 14 is provided halfway between the two. When the main steam stop valve 5 is closed, the turbine bypass valve 14 is opened and the main steam is released to the condenser 9 via the turbine bypass pipe 13f.

Further, the main steam pipe 4 is connected to a main steam relief g16 via a main steam safety relief valve 152, and this main steam relief pipe 16 communicates with the inside of the pressure suppression chamber 17. and,
When the reactor is isolated from the turbine 7, etc., the main steam safety relief valve 15 opens and the main steam safety relief pipe 161a opens.
0: Via main steam? In addition, the coolant in the reactor pressure vessel 2 is circulated through the reactor core 32 by a coolant circulation pump, such as a recirculation pump 18ζ2, and this recirculation Operation of pump 18? By controlling this, the core flow rate is controlled, and the output is controlled.

Further, 19 is a poison injection device used as a backup reactor shutdown device. This poison injection device 19 is configured to inject a neutron absorbing substance such as a boric acid solution into the reactor pressure vessel 2 (2) to stop the nuclear reaction in the reactor core 3 and shut down the reactor. In such a nuclear power generation facility f2, the main steam stop valve 5 etc. are closed, the j reactor is isolated from the turbine z side,
In addition, an output control device is provided in case of a scram (second failure), and its configuration will be explained below. In the figure, 20 is a reactor pressure detector, which detects the reactor pressure inside the reactor pressure vessel 2. 2] is a reactor power detector configured to detect pressure, which receives signals from the neutron detectors 22 provided in the reactor core 3 (2) and detects the atomic energy corresponding to the reactor output. The reactor output signal outputted from the reactor output detector 2) is configured to output a reactor output signal and is configured to be input to a set value signal output circuit 23. This set value signal output circuit 23 is configured to output a reactor pressure signal (a correspondingly hardening pressure set value signal), and this pressure set value is shown in FIG.
- indicates η11) J, i, 'j combination C where the output of the first child reactor is high
- indicates that the pressure setting value is also low, and the reactor output is low (- indicates that the pressure setting value is also low.

The pressure setting value (No. 8) output from this setting value signal output circuit 23 is configured to be input to the control circuit 24.

The control circuit 24 is also configured to receive a reactor pressure signal from the reactor pressure detector 20 indicated by fl'+J).
The control circuit 24 is connected to the comparator 2.
5 and controller 26'r: [iti? I'm getting it.

The above reactor pressure signal and pressure set value signal are generated by this comparator 2.
5 is compared and the reactor pressure is the pressure set value? C if exceeded
Second, a signal is sent from this comparator 25 to a controller 26, and this controller 26 sends a 111 circulation pump 18 and a water supply pump 72i 2 stop number, and this recirculation pump 1
8 and the water supply pump 12 are configured to stop. From this controller 26, the recirculation pump 1 is
8 and a stop signal for the water supply pump 12 (a start signal for the dual poison injection device 19 is output, and this poison injection device 19q
The set value signal output circuit 23 changes the pressure set value in response to the reactor power, and the borehole shown in FIG. If the reactor output is low, the pressure set value is set high, and if the reactor pressure is low, the pressure set value is set low. Therefore, when the nuclear reactor is operated at the rated output, the pressure setting value of C is high to prevent malfunction. In addition, if the reactor is isolated from the turbine 7 side in such a rated power operating state and a scram fails, the reactor pressure will rise by a wide range C2, so if the pressure setting is high like this, Also, if the reactor output is low, the pressure setting value will be low. As shown by the solid line, the third reason is that even if the rise in the reactor pressure is small, the pressure setting value is still low, so the reactor pressure reaches the pressure setting value in a short period of time, exceeds i, and the recirculation pump is turned off. 8 stops.Therefore, the core flow rate decreases and the core 3
The void ratio in the main steam safety relief valve J5Y increases, and the reactor output decreases as shown by the two solid lines in Figure 4C.
The amount of excess steam released to the pressure suppression chamber N17 is reduced in a short time, and the rise in the temperature of the pool water in the pressure suppression chamber 12 is suppressed to a low level as shown by the double solid line T in FIG. 5C. In addition, the broken lines in FIGS. 3-7 to 5 indicate the conventional case, that is,
In the conventional system, even when the reactor output is low, the pressure setting value remains high (-) as shown in Figure 3, so if the reactor is isolated in this state and scram fails, C2 or If the rise in the reactor pressure is small as shown by the broken line, the reactor pressure does not reach the set pressure value, and therefore the output control device does not operate. Therefore, the recirculation pump can be operated properly, so the reactor output does not decrease as shown by the broken line in Figure 4, and the steam generation does not decrease, so excess steam flows into the pressure suppression chamber via the main steam safety relief valve. continue to be missed,
As shown by the broken line in FIG. 5, the temperature of the pool water in the pressure suppression chamber increases.

In addition, the above-mentioned set value signal output circuit has a blank reactor output number fx
Instead of inputting @, another process corresponding to the reactor output C2, that is, a signal corresponding to the reactor output may be input. As the reactor output corresponding signals, for example, the recirculation drive flow signal, the core Mt quantity signal, the turbine output signal, and the main steam flow signal may be used. Figure 7 shows the relationship between the core flow rate and pressure set value when the core flow signal is used, and Figure 8 shows the relationship between the core flow rate and pressure set value when the core flow signal is used. The relationship between the turbine output and the pressure setting value when a signal is used is shown, and FIG. 9 shows the relationship between the main steam flow rate and the pressure setting value when the main steam flow rate No. 41 is used. show.

Zara(2) This example shows that when the recirculation pump is stopped (
Stopping the two water supply pumps and starting the poison injection device? Although the system has been configured such that the water supply pump is stopped and the poison injection device is started using a separate control system, the present invention is compatible with the reactor output and is compatible with the constant reactor output. Input the Hakugo into the set value output circuit, change the pressure set value 2 according to the reactor output, output a high pressure set value when the j Oji reactor output is high, and output the high pressure set value when the j Oji reactor output is low ( 2 outputs a low pressure set value, the control circuit compares this pressure set value with the reactor pressure, and if the reactor pressure exceeds this pressure set value, the C2 coolant circulation pump is stopped. Therefore, when the reactor output is high, such as when the reactor's rated output is turned to 1.5°, the pressure setting value becomes high, and the difference from the reactor pressure during rated operation becomes large, resulting in a slight possibility of malfunction (- prevented and
If the reactor power is low, the pressure set value will be low, so
In such a situation, when the reactor is isolated from the load side and scram C2 fails, the coolant circulation pump will be reliably stopped even if the reactor pressure rises too rapidly.
Its effects, such as being able to reduce the output of a nuclear reactor, are 0

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of one embodiment of the present invention. Figure 2 is a diagram showing the relationship between reactor output and pressure setting. Figure 3 is a diagram showing the relationship between reactor output and pressure setting. Figure 4 is a diagram showing the fluctuation of the reactor pressure in the event of a scram failure. Figure 4 is a diagram showing the variation in the reactor output (mw%). Figure 5 is a diagram showing the 1M degree rise in the pressure suppression room pool water. be. Also, is Fig. 6 the recirculation rotational flow rate? Figure 7 shows the relationship between the recirculation drive flow rate and pressure set value when used as a signal corresponding to reactor output. Figure 8 shows the relationship between the turbine signal and the pressure setting when the turbine output signal is used as a signal corresponding to the reactor output, and Figure 9 shows the main steam flow rate signal. D is a diagram showing the relationship between main steam flow rate and pressure setting value when used as a reactor output corresponding signal. 2... Reactor pressure vessel, 3... Reactor core, 7... Turbine, 12... ...Water supply pump, 17...Pressure suppression chamber. 18... Recirculation pump (coolant circulation pump), 19.
... Poison injection device, 20... Reactor pressure detector. 2. Nuclear reactor output detector! reactor output corresponding value detector), 23... set value signal output circuit, 24... control circuit. Applicant's Patent Attorney Hiko Rin Ushiki Figure 2 Figure 3 Figure 4 Time Figure 5 Figure 6 Figure 7 00 53L tatami (0m) to the bar

Claims (1)

[Claims] (1) A reactor pressure detector that detects reactor pressure;
Reactor power or process R corresponding to this reactor power
and an atomic power corresponding value detector that detects the detected value and outputs a corresponding nuclear reactor output signal. Reactor output corresponding signal from this reactor output corresponding value detector? When the reactor output is low, the receiver outputs a high pressure set value signal, and when the reactor output is low, it outputs a low pressure set value signal? What is the set value signal output circuit to output, the pressure set value from this set value signal output circuit, and the J Kyoko reactor pressure signal from the reactor pressure detector? An output control device for a boiling water reactor, characterized by comprising a control circuit that outputs a stop signal for a coolant circulation pump when the reactor pressure exceeds a pressure set value. The output control device for a boiling water reactor according to the patent, characterized in that the control circuit outputs a stop signal for the feed water pump and a start signal for the poison injection device as well as the stop signal for the coolant circulation pump. .