JPH0943392A - Reactor output control determination device - Google Patents

Abstract

(57) [Abstract] [Problem] Setting a threshold value for the vertical motion of the seismic wave or the acceleration of the vertical motion and the horizontal motion to detect medium-scale or larger earthquakes at the stage of the initial microtremor, and to detect it in advance before the arrival of the main motion. (EN) Provided is a reactor power control determination device that lowers reactor power to avoid scrum. A reactor power control determination device according to claim 1,
Vertical motion detector that detects vertical motion acceleration from seismic signals 17
When the horizontal motion detector 18 for detecting the horizontal motion acceleration and the vertical motion and horizontal motion acceleration input by connecting to the vertical motion detector 17 and the horizontal motion detector 18 exceed the threshold value of 10 to 20 Gal. Redundant logic circuits 19-21 that output judgment signals
And a wipeout circuit 23 connected to the vertical movement logic circuit 19 and connected to the horizontal movement logic circuits 20 and 21 via the OR circuit 22 to output a lowering signal, and an output lowering to lower the reactor output by the lowering signal. And a device 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor power control determination apparatus for continuously operating a nuclear reactor even during an earthquake.

[0002]

2. Description of the Related Art In a boiling water reactor, as shown in the system diagram of FIG. 8, the output control of the reactor 1 is controlled by the position of the control rod 2, the recirculation flow rate by the recirculation pump 3, and , The main steam control valve 4 and the turbine bypass valve 5 are used to control the reactor pressure.

At the time of an earthquake, this earthquake is measured by the seismometer 6 which is a detecting means, the magnitude of the earthquake is judged by the judging means 7, and the initial tremor is detected as shown in the seismic waveform diagram of FIG. Then, before the main movement arrives, the output reduction means 8 reduces the output of the nuclear reactor 1 by the various controls described above.

Conventionally, in the reactor 1, there is a reactor 1 in which an output increase occurs and a scrum occurs when an earthquake of a medium scale or more occurs. That is, in a nuclear power plant, in order to ensure operational safety, the acceleration due to earthquake vibration is detected at the time of an earthquake, and in the case of a large-scale earthquake, if the acceleration exceeds a predetermined set value, the reactor Scrum 1 to stop automatically.

When the magnitude of the earthquake is not so large, the operation of the nuclear reactor 1 is continued without change from the viewpoint of preventing damage to the reactor equipment and stable supply of electric power.

[0006]

As shown in the enlarged perspective view of the essential part of FIG. 10, the core structure of the nuclear reactor 1 is such that four sets of fuel assemblies 9 are connected to one control rod 2 by spacers 10. , And is flexibly supported by the channel fasteners 12 on the upper lattice plate 11. Therefore, when acceleration is applied in the horizontal direction, the lower end of the fuel assembly 9 is fixed by the core support plate 13 and the fuel support fitting 14 and does not change, but the upper part is tilted due to deformation of the channel fastener 12. There is.

In this case, the distance between the tilted fuel assembly 9 and the fuel assembly 9 supported by the upper lattice plate 11 and not tilted changes. In the part where this interval is increased, the coolant may invade, whereby the moderating action of neutrons may proceed and the output of the nuclear reactor 1 may increase.

The response to the earthquake in the reactor 1 is to ensure the safety of the reactor 1 when the neutrons in the core rise to a preset neutron flux high scrum set point (120%) due to an earthquake of medium scale or larger. I've been scramming for the purpose. However, although the reactor 1 is automatically stopped by this scrum, stopping the reactor 1 without any trouble to the reactor equipment keeps the safe operation, but on the other hand, the nuclear power plant Since the operating rate declined, there was an obstacle to impairing the stable supply of electricity.

The object of the present invention is to set a threshold value for the vertical motion or vertical motion and horizontal motion acceleration of a seismic wave so that a seismic motion of a medium scale or larger in which the reactor may scrum is subjected to the initial microtremor. It is to provide a reactor power control determination device that senses at the stage of (1) and reduces the reactor power in advance before the arrival of the main motion to avoid a scrum.

[0010]

In order to achieve the above object, an output control determination device for a reactor according to a first aspect of the present invention is a vertical motion detector for detecting vertical motion acceleration from an earthquake signal input from a seismometer. Similarly, a horizontal motion detector that detects horizontal motion acceleration from the input seismic signal, and a plurality of vertical motion accelerations and horizontal motion accelerations input by connecting to the vertical motion detector and the horizontal motion detector are 10 to A redundant vertical and horizontal logic circuit that outputs a judgment signal when the threshold value set to 20Gal is exceeded is provided.

Further, a wipeout circuit connected to the vertical movement logic circuit and connected to the horizontal movement logic circuit via an OR circuit, and an output for lowering the output of the nuclear reactor by a drop signal from the wipeout circuit. And a lowering device.

The seismic signal detected by the seismograph is used to detect vertical motion acceleration and horizontal motion acceleration by the vertical motion detector and the horizontal motion detector, and output them to the vertical motion logic circuit and the horizontal motion logic circuit, respectively. The vertical motion logic circuit and horizontal motion logic circuit are set with a threshold value of 10 to 20 Gal that is appropriately judged as an earthquake of medium scale or larger.If only the vertical motion acceleration exceeds the threshold value, it will be regarded as an initial microtremor. It is determined that a medium-scale earthquake has arrived.

As a result, the output descent device lowers the output power of the reactor before the arrival of the main motion of the earthquake, and avoids the scram of the reactor even if the main motion arrives and the reactor output increases later. . If both vertical and horizontal accelerations exceed the threshold, it is judged that a large-scale earthquake or the main motion of an earthquake has already arrived, and the reactor is safely shut down by a separately set reactor scrum. Let

According to a second aspect of the present invention, there is provided a reactor power output control determination device which detects a vertical motion acceleration from a seismic signal input from a seismometer and a horizontal motion acceleration from the seismic signal input. The horizontal motion detector for detection and a plurality of vertical motion accelerations input by connecting to the vertical motion detector are
A redundant vertical motion logic circuit that outputs a judgment signal when the threshold value set to 10 to 20 Gal is exceeded, and a plurality of horizontal motion accelerations that are input by connecting to the horizontal motion detector
A redundant horizontal motion logic circuit is provided that outputs a judgment signal when it falls below the threshold value set for Gal.

An AND circuit connected to the vertical movement logic circuit and also connected to the horizontal movement logic circuit via an OR circuit, and an output lowering device for lowering the output of the nuclear reactor by a lowering signal from the AND circuit. It is characterized by consisting of.

A vertical motion detector and a horizontal motion detector detect vertical motion acceleration and horizontal motion acceleration of the seismic signal detected by the seismograph, and output them to the vertical motion logic circuit and the horizontal motion logic circuit, respectively. The vertical motion logic circuit and horizontal motion logic circuit are set with a threshold value of 10 to 20 Gal that is appropriately judged as an earthquake of medium scale or larger.If only the vertical motion acceleration exceeds the threshold value, it will be regarded as an initial microtremor. It is determined that a medium-scale earthquake has arrived.

As a result, the output descent device lowers the output power of the reactor before the arrival of the main motion of the earthquake, and avoids the scram of the reactor even if the main motion reaches and the reactor output increases later. . If both vertical and horizontal accelerations exceed the threshold, it is judged that a large-scale earthquake or the main motion of an earthquake has already arrived, and the reactor is safely shut down by a separately set reactor scrum. Let

According to a third aspect of the present invention, there is provided a reactor output control determining apparatus, wherein the vertical motion detector and the horizontal motion detector each have a maximum value from an individual maximum value of acceleration due to an input seismic signal to each time point. Is provided with a peak value storage device for constantly updating and storing.

Even if the maximum vertical movement acceleration exceeds the threshold value, the horizontal movement acceleration at that time may be much lower than the threshold value. However, the peak value storage device is used before and after the maximum value of vertical acceleration exceeds the threshold value.
In the range of up to 1000 msec, highly accurate judgment can be performed by judging the earthquake scale using the maximum value of horizontal dynamic acceleration.

According to a fourth aspect of the present invention, there is provided a reactor power control determining device, wherein a seismometer is installed near the reactor and a plurality of seismometers are arranged at a position remote from the reactor. To do. The seismometers A to D provided at positions far from the plant can detect the seismic wave propagating due to the occurrence of the earthquake earlier than the seismometer E in the plant, and can notify the arrival of the earthquake to the plant early.

Thus, the arrival of the earthquake can be known in the nuclear power plant earlier, and the earthquake scale can be judged and dealt with before the shaking of the nuclear power plant. Further, the direction of arrival of the earthquake can be known from the seismic detection time difference between the seismographs A to E.

According to a fifth aspect of the present invention, there is provided a reactor power control determining apparatus, wherein a seismograph is installed above a casing of a recirculation pump. Since the upper part of the casing of the recirculation pump is a part that is relatively sensitive to external vibration, the initial vibration of the earthquake can be detected with high sensitivity by detecting the earthquake motion with the vibrometer installed here. be able to.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same components as those of the above-described conventional technique are designated by the same reference numerals, and detailed description thereof will be omitted. First
The embodiment relates to claim 1, and as shown in the logic block diagram of FIG. 1, the reactor power control determination device 15 which is the seismic scale determination means includes a plurality of seismographs which are seismic wave detection means (not shown). Vertical motion detector 17 that inputs vertical seismic signal 16 to detect vertical motion (UD) acceleration, and also inputs seismic signal 16 to, for example, north-south (NS) and east-west (EW) horizontal motion in two directions. A horizontal motion detector 18 for detecting acceleration is provided.

The vertical movement detector 17 has an acceleration threshold value set to 10 to 20 Gal, and the vertical movement detector 17
A vertical movement 2/3 logic circuit 19 having a redundant function of inputting a plurality of vertical movement accelerations from the above, and outputting a judgment signal when the vertical movement acceleration exceeds the threshold value is connected.

Further, the horizontal motion detector 18 is set with a threshold value of acceleration of 10 to 20 Gal, and a plurality of horizontal motion accelerations from the horizontal motion detector 18 are inputted. Horizontal movement in the north-south direction with a redundant function that outputs a judgment signal when the threshold value is exceeded 2/3 Logic circuit 2
0, and horizontal movement 2/3 logic circuit 21 in the east-west direction is connected.

The vertical movement 2/3 logic circuit 19 directly
Further, the horizontal movement 2/3 logic circuits 20 and 21 are connected to a wipeout circuit (W.O) 23 via an OR circuit 22, and a drop signal 26 from the wipeout circuit 23 causes an output drop of the reactor 1. It is output to an output lowering device 24 which is a means, and this output lowering device 24 is provided with, for example, a 10% reduction runback setting 25 of the reactor recirculation system.

Next, the operation of the above configuration will be described. In the output control determination device 15, the vertical motion acceleration based on the seismic signal 16 input by the vertical motion detector 17 has a threshold value of 10 to 20 Ga.
If it exceeds l, the vertical movement 2/3 logic circuit 19 outputs a judgment signal. This judgment signal is the wipeout circuit
Output descending device 24 is input as descending signal 26 via 23,
The reactor output is reduced by about 5 to 20% of the rated output by decreasing the number of revolutions of the recirculation pump 3 and inserting the selective control rod 2.

For example, the rated output of the reactor 1 can be reduced by 5 to 20% by the reactor recirculation system runback operation which is reduced by about 10%. The condition that the descent signal 26 is output from the wipeout circuit 23 is that the magnitude of the horizontal motion acceleration by the seismic signal 16 input to the horizontal motion detector 18 is the horizontal motion.
2/3 of the threshold values set in the logic circuits 20 and 21
It is the case of 10 to 20 Gal or less.

That is, in general, there is a tendency for the vertical motion to be large during the main motion due to the horizontal motion. If the vertical motion is used for the judgment, even a small earthquake may be judged as a medium-scale earthquake or more. is there. Therefore, in order to make a highly accurate judgment, consider the earthquake motion in the horizontal direction, and in addition to the initial fine motion of the vertical motion, a logic using the main motions of the vertical motion and the horizontal motion is constructed. And, when the horizontal movement is 10 to 20 Gal or less, the output lowering device is activated.

As a result, when the vertical motion acceleration exceeds the threshold value and the horizontal motion acceleration is equal to or less than the threshold value, it is determined that the earthquake is of a medium scale and the initial fine motion of the vertical motion preceding the main motion is detected. Then, the output drop control of the reactor 1 by the output drop device 24 is performed. If the vertical motion acceleration exceeds the threshold value and the horizontal motion acceleration also exceeds the threshold value, it is determined that the earthquake is a large-scale earthquake or the main motion has already reached.

In this case, even if the rated output of the reactor 1 is reduced by 5 to 20%, the effect is not obtained and the reactor 1 is set separately from the viewpoint of ensuring the safety of the reactor 1. Prioritize reactor shutdown due to scrum. Therefore, the horizontal movement 2/3 logic circuits 20 and 21 output a determination signal to the wipeout circuit 23 via the OR circuit 22 when the horizontal movement acceleration exceeds the threshold value. Since the wipeout circuit 23 cuts off the output of the down signal 26, the output down control of the reactor 1 by the output down device 24 is stopped.

As shown in the seismic waveform diagram of FIG. 2, in the case of a normal earthquake, the seismic wave transmits the initial tremor before the main tremor of the quake. Since the vertical motion acceleration of this seismic signal 16 has reached the threshold value of 10 to 20 Gal,
Vertical motion 2/3 Logic circuit 19 determines that the earthquake is a medium-scale or larger.

The determination signal is 2 to 2 before the operation for suppressing the neutron flux increase due to the earthquake in the reactor 1.
It is desirable to output 3 seconds before. Also, the threshold of 10
~ 20Gal was selected as an appropriate value from past seismic observation data, reactor scrum, and neutron flux height warning data.

Further, the reactor output is 5 to the rated output in advance.
If the neutron flux in the core increases due to the main motion of the earthquake, it will not reach the separately set neutron flux high scrum set point (120%) if it is reduced by about 20%, and the reactor 1
It is possible to avoid the stop due to the scrum.

The second embodiment relates to claim 2, and as shown in the logic block diagram of FIG. 3, the reactor output control judging device 27, which is a means for judging the magnitude of the earthquake, inputs the earthquake signal 16 and moves up and down. A vertical motion detector 17 for detecting a dynamic (UD) acceleration and a horizontal motion detector 18a for inputting an earthquake signal 16 to detect a horizontal motion (NS) (EW) acceleration are provided.

The vertical movement detector 17 has a threshold acceleration value set to 10 to 20 Gal and the vertical movement detector 17
A vertical movement 2/3 logic circuit 19 having a redundant function of inputting a plurality of vertical movement accelerations from the above, and outputting a judgment signal when the vertical movement acceleration exceeds the threshold value is connected.

Further, the horizontal motion detector 18a is set with an acceleration threshold value of 10 to 20 Gal, and a plurality of horizontal motion accelerations from the horizontal motion detector 18a are inputted. Horizontal motion 2/3 logic circuits 20 and 21 with redundancy function to output judgment signal below threshold
Connect.

The vertical movement 2/3 logic circuit 19 directly
Further, the horizontal movement 2/3 logic circuits 20 and 21 are connected to an AND circuit 28 via an OR circuit 22, and the descending signal 26 from the AND circuit 28 is an output descending device which is an output descending means of the nuclear reactor 1.
Output to 24. The output lowering device 24 is provided with, for example, a 10% reduction runback setting 25 of the reactor recirculation system.

Next, the operation of the above configuration will be described. In the output control determination device 27, the vertical acceleration due to the seismic signal 16 input by the vertical motion detector 17 has a threshold value of 10 to 20 Ga.
If it exceeds l, the vertical movement 2/3 logic circuit 19 outputs a determination signal to the AND circuit 28.

Further, in the horizontal motion detector 18a, the horizontal motion acceleration due to the input seismic signal 16 is a threshold value of 10 to 20.
In the case of Gal or less, the horizontal movement 2/3 logic circuits 20 and 21 output the determination signal to the AND circuit 28 via the OR circuit 22. When the horizontal dynamic acceleration exceeds the threshold value of 10 to 20 Gal, the output of the determination signal from the horizontal dynamic 2/3 logic circuits 20 and 21 is stopped.

Therefore, in the AND circuit 28, the vertical movement 2/3 logic circuit 19 and the horizontal movement 2 via the OR circuit 22 are used.
/ 3 When the determination signals are input from both the logic circuits 20 and 21, the down signal 26 is output to the output down device 24, and the reactor 1
5% to 20% of the rated output is controlled against.

Even if the vertical movement acceleration in the vertical movement 2/3 logic circuit 19 exceeds the threshold value, the horizontal movement acceleration exceeds the threshold value in the horizontal movement 2/3 logic circuits 20 and 21. In this case, the down signal 26 is not output from the AND circuit 28, and the output down control of the reactor 1 by the output down device 24 is not performed. That is, if the vertical acceleration exceeds the threshold,
When the horizontal dynamic acceleration is below the threshold value, it is judged that the earthquake is of a medium scale and the initial fine motion of vertical motion preceding the main motion is detected, and the output lowering control of the reactor 1 is performed by the output lowering device 24 To do.

As a result, even if the main motion of the earthquake arrives at the reactor 1 at a later time and the output increases due to the increase of the neutron flux in the reactor due to the vibration, the output of the reactor 1 is lowered in advance. As a result, the reactor 1 does not become a scrum and the safety of the nuclear power plant is ensured.
It is possible to prevent a decrease in operating rate. When the vertical motion acceleration exceeds the threshold value and the horizontal motion acceleration also exceeds the threshold value, it is determined that the earthquake is a large-scale earthquake or the main motion has already reached.

In this case, even if the power drop control is performed on the reactor 1, the effect is not obtained, and the reactor is stopped by the reactor scrum which is separately set from the viewpoint of ensuring the safety of the reactor 1. Prioritize. Also, the threshold is 10-20Gal
With respect to the reason and other actions and effects, the same effects as those of the first embodiment are obtained.

The third embodiment relates to claim 3 and, as shown in the block diagram of FIG.
Is the maximum value from each maximum value, which is the individual peak of acceleration in the seismic signal input to the vertical motion detector 17 and horizontal motion detector 18 shown in FIG. 1 of the first embodiment, to each time point. A peak value storage device 30 that is constantly updated and stored is provided, and a vertical motion detector 31 and a horizontal motion detector 32 are provided, and the other configurations are similar to those of the first embodiment.

Next, the operation of the above configuration will be described. In the determination of the earthquake scale by the output control determination device, if the maximum value of the vertical acceleration of the earthquake signal 16 exceeds the threshold value, the horizontal acceleration of the earthquake signal 16 happens to fall significantly below the threshold value. , It is mistakenly judged as the initial tremor of a medium-scale earthquake or less.

On the other hand, in the peak value storage device 30, for example, when the seismic wave shown in the seismic waveform diagram of FIG. (Maximum acceleration A) is stored. Next, if the maximum acceleration B of the peak value newly generated at time b is A> B, the maximum acceleration A is stored in the peak value storage device 30 as it is.

Further, when the maximum acceleration C of the peak value generated at time c is A <C, the maximum acceleration A is updated to the maximum acceleration C and stored in the peak value storage device 30. Thus, when the maximum value of vertical motion acceleration exceeds the threshold value, the maximum acceleration value of horizontal motion stored in the peak value storage device 30 in the range of 500 to 1000 msec before and after exceeding the threshold value is used. Determine the scale of the earthquake.

As a result, even when the vertical motion acceleration exceeds the threshold value, even if the horizontal motion acceleration is significantly lower than the threshold value, the peak value storage device 30 sets the vertical motion acceleration threshold value to the threshold value. Since the maximum acceleration value of the horizontal dynamic acceleration is updated and stored before and after the crossing, the accuracy of the earthquake scale determination is improved by making an online determination based on this maximum acceleration.

The fourth embodiment relates to claim 3 and, as shown in the block diagram of FIG.
The vertical movement detector 17 and the horizontal movement detector 18a shown in FIG. 3 of the second embodiment are each provided with a peak value storage device 30 to form a vertical movement detector 31 and a horizontal movement detector 32a. The other configurations are similar to those of the second embodiment. The operation of the peak value storage device 30 in the above configuration is the same as that of the above-described third embodiment, and there is an effect that the determination accuracy of the earthquake scale can be obtained with high accuracy. The same effect as can be obtained.

The fifth embodiment relates to claim 4, and FIG.
As shown in the seismograph layout diagram, the seismograph 6 serving as an earthquake detection means is installed concentrically with four seismographs A to D at a remote location several kilometers away from the nuclear power plant, and the central nuclear power A seismometer E is installed in the power plant.

The operation of the above configuration is that seismographs A to D provided at a distance from the plant cause seismic waves propagating due to the occurrence of an earthquake to arrive earlier than seismograph E in the plant. The arrival of an earthquake can be detected early. The detection of the generated seismic wave is performed by seismographs A to D closer to the epicenter than the seismograph E as shown in FIG.
Is obtained earlier with a difference of several seconds depending on the mutual distance with the seismograph E.
When the acceleration due to exceeds the threshold value, the seismic signal 16 is obtained earlier than the seismograph E in the plant.

Since the seismic signal 16 is transmitted to the nuclear power plant sooner than the arrival of the seismic motion, the seismic detection and the seismic scale determination can be performed prior to the shaking of the reactor. The time of this early detection is proportional to the separation distance between the seismographs A to D and the seismograph E, and the propagation direction is detected by the positional relationship between the seismographs A to D and the seismograph E, and the direction detection accuracy. Varies depending on the number of seismometers A to D arranged.

The sixth embodiment relates to the fifth aspect, and is constituted by installing the seismograph 6 in the plant, which is an earthquake detecting means, on the upper part of the casing of the recirculation pump 3 shown in FIG. Since the recirculation pump 3 is installed in the vicinity of the reactor 1, the operation of this configuration has no difference in the arrival time of the seismic wave from the reactor 1.

Further, the upper portion of the casing of the recirculation pump is a portion relatively sensitive to external vibration, and therefore the vibrometer installed here can detect the initial microtremor of the earthquake with high sensitivity. You can Therefore, the detection accuracy is high and the mounting is easy.

[0056]

As described above, according to the present invention, it is possible to avoid the reactor scrum due to the earthquake motion by suppressing the increase of the reactor power by the high detection accuracy and the appropriate determination of the earthquake scale for the earthquakes of the medium scale or larger. The nuclear power plant operating rate and economic efficiency,
It also has the effect of improving the stability of power supply.

[Brief description of drawings]

FIG. 1 is a logic configuration diagram of an output control determination device according to a first embodiment of the present invention.

FIG. 2 is a seismic waveform diagram of horizontal motion and vertical motion according to the first embodiment of the present invention.

FIG. 3 is a logic configuration diagram of an output control determination device according to a second embodiment of the present invention.

FIG. 4 is a logic configuration diagram of an output control determination device according to a third embodiment of the present invention.

FIG. 5 is an earthquake waveform diagram of the third embodiment according to the present invention.

FIG. 6 is a logic configuration diagram of an output control determination device according to a fourth embodiment of the present invention.

7 (a) is a seismograph installation diagram and FIG. 7 (b) is an earthquake waveform diagram in a fifth embodiment according to the present invention.

FIG. 8 is a system configuration diagram of a nuclear power plant.

[Fig. 9] Earthquake waveform diagram.

FIG. 10 is an enlarged perspective view of a main part of the core.

[Explanation of symbols]

1 ... Reactor, 2 ... Control rod, 3 ... Recirculation pump, 4 ... Main steam control valve, 5 ... Turbine bypass valve, 6 ... Seismometer, 7 ...
Judgment device, 8, 24 ... Output lowering device, 9 ... Fuel assembly, 10
... Spacer, 11 ... Upper lattice plate, 12 ... Channel fastener, 13 ... Core support plate, 14 ... Fuel support metal fittings, 15, 27, 29,
33 ... Output control judgment device, 16 ... Earthquake signal, 17, 31 ... Vertical motion detector, 18, 18a, 32, 32a ... Horizontal motion detector, 19 ... Vertical motion 2/3 logic circuit, 20, 21 ... Horizontal motion 2/3 logic circuit, 22 ... OR circuit, 23 ... Wipeout circuit (W.O),
25… 10% reduction Recirculation system runback setting, 26… Descent signal, 28
... AND circuit, 30 ... Peak value storage device, A to D ... Surrounding seismometer, E ... Plant seismometer.

Claims (5)

[Claims] 1. A vertical motion detector that detects vertical motion acceleration from an earthquake signal input from a seismograph, a horizontal motion detector that detects horizontal motion acceleration from the same input seismic signal, and the vertical motion detector and the horizontal motion detector. Multiple vertical accelerations and horizontal accelerations input by connecting to each of the motion detectors
A redundant vertical movement and horizontal movement logic circuit that outputs a determination signal when the threshold value set to 20 Gal is exceeded, and the vertical movement logic circuit and the horizontal movement logic circuit are connected through an OR circuit. An output control determination device for a nuclear reactor, comprising a wipeout circuit and an output lowering device that lowers the output of the nuclear reactor in response to a drop signal from the wipeout circuit. 2. A vertical motion detector that detects vertical motion acceleration from an earthquake signal input from a seismometer, a horizontal motion detector that detects horizontal motion acceleration from the same input seismic signal, and a connection to the vertical motion detector. The vertical accelerations
A redundant vertical motion logic circuit that outputs a judgment signal when the threshold value set to 10 to 20 Gal is exceeded, and a plurality of horizontal motion accelerations that are input by connecting to the horizontal motion detector
A redundant horizontal movement logic circuit that outputs a determination signal when the value falls below the threshold value set in Gal, and is connected to the vertical movement logic circuit and is ORed with the horizontal movement logic circuit.
An output control determination device for a nuclear reactor, comprising an AND circuit connected via a circuit, and an output lowering device that lowers the output of the nuclear reactor by a down signal from the AND circuit. 3. The vertical motion detector and the horizontal motion detector are provided with a peak value storage device for constantly updating and storing the maximum values from the individual maximum values of the acceleration due to the input seismic signal to each time point. The power control determination device for a nuclear reactor according to claim 1, wherein: 4. The reactor power control determination device according to claim 1, wherein the seismograph is installed in the vicinity of the reactor, and a plurality of seismometers are arranged at a position remote from the reactor. 5. The reactor power control determination device according to claim 1, wherein the seismograph is installed above the casing of the recirculation pump.