JPH07294688A - Reactor power monitor - Google Patents

Abstract

PURPOSE:To improve reliability and response speed of a reactor power monitor by reducing the number of devices existing in the transmission path for commonly held detector outputs. CONSTITUTION:As for the detector output of a commonly used detector 1b, before it reaches a digital operator 35 by way of an analog-digital converter 34 of a device 31 on the transmission side, it is separated with a signal separation output part 33 placed behind a detector signal input part 32 of the device 31 on the transmission side and is supplied to the input of the analog-digital converter 34 in the device 32 on the reception side. Therefore, only a signal separation output part 33 must be added to the detector output path for the commonly held neutron detector 1b compared with the detectors 1a and 1b which are not commonly held and so the number of devices existing in the transmission path for the commonly held detector output can be drastically reduced compared with the case using data transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor output monitoring device for monitoring the reactor output by using the output of a neutron detector installed inside a nuclear reactor core, and more particularly to a redundant detector output of the neutron detector. The present invention relates to a reactor output monitoring device configured to be shared by a plurality of integrated monitoring devices.

[0002]

2. Description of the Related Art Generally, in a nuclear power generation facility, in order to ensure the reliability of a reactor output monitoring device, the device is redundantly provided with a plurality of monitoring systems. Each of the plurality of redundant monitoring systems monitors the output of the plurality of neutron detectors installed inside the reactor core. However, since the number of neutron detectors installed inside the reactor core is small in small reactors with small output, it is difficult to secure the number of detectors that can be monitored independently for each system. Is. Therefore, in the reactor output monitoring device used in this type of small reactor, the detector output is shared among a plurality of monitoring systems.

A neutron detector used in a reactor power monitoring system is composed of a uranium metal, which is a fission material, as an electrode.
The charged particles generated by nuclear fission caused by the injection of neutrons are collected by the electrode to which a high voltage is applied and detected as a current signal.

Therefore, when the detector is irradiated with neutrons, the nuclear reaction reduces the amount of fissile material, which gradually deteriorates the detection sensitivity to neutrons. In particular, the detector installed inside the reactor core is always exposed to a strong neutron flux while the reactor is in operation, so that the sensitivity deteriorates with time.

Therefore, in the reactor output monitor, it is necessary to calibrate the detector signal output at regular intervals. The calibration of the detector signal output is usually performed as follows. That is, in the reactor power monitoring device, the output current signal that is the detector output is converted into the reactor output% (the detector signal output for the neutron flux intensity at the reactor center when the reactor is producing the rated output). The gain of the circuit for converting into a voltage signal is adjusted in accordance with the value (determined to be 100%).

FIG. 5 shows the configuration of a conventional typical reactor power monitoring device. This reactor output monitoring device is an analog system using an analog circuit, and does not use a microprocessor. The arithmetic circuit using an operational amplifier performs gain adjustment and comparison with a trip value.

In FIG. 5, devices 11 and 12 forming two systems of a plurality of redundant monitoring systems are representatively shown. In each of these devices 11 and 12, the detector signals from the corresponding neutron detectors 1 a and 1 b, that is, the current signal composed of the charged particles collected by the high-voltage power supply 2 is given to the gain adjusting circuit 3. In the gain adjusting circuit 3, the current signal is converted into a voltage signal corresponding to the output% of the nuclear reactor, and then output to the output circuit 4, the averaging circuit 5, and the trip comparison circuit 6 in parallel.

Since the device 11 and the device 12 share the detector output with each other now, the output of the gain adjusting circuit 3 of the device 11 is branched and connected to the averaging circuit 5 of the device 12 through the output circuit 4. In addition, the output of the gain adjusting circuit 3 of the device 12 is also output via the output circuit 4 to the averaging circuit 5 of the device 11.
It is branched and connected to.

As described above, in the conventional analog system, the gain-adjusted detector output is sent to the other device, so that in the averaging circuit 5 of each device 11 and 12, the detector from the other device is detected. It was not necessary to adjust the output gain.

However, in such an analog system, in order to adjust the gain of each of the detectors 1a and 1b, it is necessary for a human system, that is, a system administrator to adjust the variable resistor of the operational amplifier which constitutes the gain adjusting circuit 3. Therefore, there is a drawback that the adjustment takes a lot of time.

Therefore, recently, a digital reactor output monitoring device has been developed. A typical configuration example thereof is shown in FIG. This reactor output monitoring device is a digital system using a microprocessor, and most of the calculations are performed by software processing by the microprocessor.

In FIG. 6, devices 21 and 22 forming two systems of a plurality of redundant monitoring systems are representatively shown. In this system, the detector output of the device 21 is shared by the device 21 and the device 22 by data transmission from the device 21 to the device 22.

That is, in the device 21, the detector 1
The detector outputs of a and 1b are respectively converted from current signals to voltage signals by the current / voltage converter 22 and then sent to the signal line selector 24, where the detectors 1a and 1b are detected.
One of the detector outputs is selected. The selected detector output is converted into a digital signal (binary number) by the analog / digital converter 25, and then numerically calculated by software processing executed by the microprocessor 26.

In this case, in the gain adjustment of the detector, which takes a lot of time for adjustment in the analog system, the gain of the detector is stored in the gain storage device 27 such as a memory, and the value is digitally calculated. It can be easily performed by using as a calculation coefficient in the calculation.

However, in such a digital system, the detector output before the numerical calculation by software is performed does not represent the reactor output%. Therefore, in order to share the detector output, the microprocessor 26 of the device 21
The nuclear reactor output% corresponding to the detector 1a or the detector 1b obtained as a result of the calculation in 1 is sent to the data receiving device 30 of the device 22 by the data transmission device 29.

However, when the detector output is shared by the data transmission as described above, the following problems occur. (1) Reliability issues Reliable reactor equipment used in nuclear power generation facilities emphasizes reliability. Since the failure rate of a device is the sum of the failure rates of the constituent elements of the apparatus, the smaller the number of constituent elements included in the transmission path of the detector output, the higher the reliability.
However, in the system of FIG. 6, as shown in FIG. 7, the path of the detector output when the detector output is shared is different from that in the case where the detector output is not shared. In addition, the microprocessor 26 of the device 22 becomes longer and the reliability is reduced.

(2) Problem of response time In the reactor power monitoring system, the reactor must be stopped before the core becomes supercritical even in the event of a reactor accident. Is required.

However, since the calculation by the microprocessor is executed by sequentially calling the program, there is a delay time corresponding to the execution time of the program between the input and the output of the reactor output monitor. Further, the output signal is updated every program execution cycle, and is discontinuous in time. Also in data transmission, time is required according to the transmission speed and the amount of data. Therefore, it has been difficult to obtain sufficient response characteristics in the conventional system in which the arithmetic means using the microprocessor and the data transmission means are stacked in multiple stages.

[0019]

As described above, the conventional digital reactor output monitoring device has a configuration in which the detector output is shared by data transmission. On the other hand, there is a drawback that the number of devices existing in the shared detector output transmission path is increased, which makes it impossible to obtain sufficient performance in terms of reliability and responsiveness of the reactor power monitoring device. It was

The present invention has been made in view of the above circumstances, and it is possible to reduce the number of devices existing in the transmission path of the shared detector output so that the small reactor which requires the shared detector output. It is an object of the present invention to provide a digital reactor output monitoring device that can realize sufficient reliability and responsiveness.

[0021]

In order to achieve the above object, in the invention according to claim 1, the input means for inputting the output of the neutron detector installed in the reactor core, and the input means And the analog-to-digital converter that converts the detector output into a digital value.
A plurality of redundant monitoring devices, each of which has a digital calculation means for calculating a digital value corresponding to the detector output outputted from the digital conversion means and monitoring the reactor output of the reactor. In a reactor power monitoring device configured to share a given neutron detector between at least those first and second devices by transmitting a detector output from a first device in the monitoring device to a second device, A detector that is provided after the input means of the first device, branches the detector output of the shared object detector output from the input means, and supplies the branched output to the input of the analog-digital conversion means of the second device. The output branch means is provided.

In order to achieve the above-mentioned object, in the invention according to claim 2, the detector output branching means of claim 1 is
It is configured by a circuit with an insulating function that electrically insulates and separates the input and the output.

In order to achieve the above object, in the invention according to claim 3, in addition to the configuration of claim 1, the first device on the transmission side of the detector output is provided with a predetermined external supply. A means for calibrating the output value of the detector output using the calibration coefficient is provided, and the second device on the receiving side includes the calibrated detector output obtained from the first device and the detector output branching means. The calibration coefficient corresponding to the detector output of the shared target detector is calculated based on the ratio to the supplied detector output before calibration, and the output value of the detector output is calculated using the calculated calibration coefficient. This is a configuration provided with means for calibrating.

Further, in order to achieve the above object, in the invention according to claim 4, in addition to the configuration of claim 1, the first
The device is provided with input switching means for separating the input means of the first device from the detector output of the neutron detector and excluding the detector output from the monitoring target, and the second device is provided with the input switching means. Receiving the status signal of the first
In this configuration, means for notifying the state of the input means provided in the device to the digital operation means of the second device is provided.

In order to achieve the above object, in the invention according to claim 5, in addition to the configuration of claim 1, the detection is performed by using a predetermined calibration coefficient supplied from the outside to the first device. And a means for calibrating the output value of the instrument output,
The apparatus calculates a calibration coefficient corresponding to the detector output based on the ratio of the calibrated detector output obtained in the first apparatus and the uncalibrated detector output supplied from the detector output branching means. And providing means for calibrating the output value of the detector output by using the calculated calibration coefficient, and separating the input means from the detector output of the neutron detector in the first device, and detecting the detector. An input switching unit that excludes an output from a monitoring target is provided, and the second device receives a state signal from the input switching unit and digitally calculates the state of the input unit provided in the first device by the receiving side device. This is a configuration provided with means for notifying the means.

[0026]

According to the reactor output monitoring device of the first aspect,
The detector output input by the input means is converted into a digital signal by each analog / digital conversion means,
The calculation processing is performed by each digital calculation means. The shared detector output is branched by the detector output branching means provided after the input means of the first device before it reaches the digital operation means of the first device, and the analog / digital of the second device. It is supplied to the input of the conversion means. Therefore, the detection output of the shared neutron detector is not shared in the path until the detector output of the shared neutron detector reaches the digital calculation means of the second device on the reception side, as compared with the case of the normal detector output of the neutron detector. The number of device output branching means is simply increased, and the number of devices existing in the shared detector output transmission path can be significantly reduced as compared with the case of using data transmission between digital operation means.

Since the failure rate of the device is the sum of the failure rates of the constituent elements of the apparatus, the smaller the number of constituent elements, the higher the reliability. In particular, the shared detector signal is the first
Passing the data to the second device without passing through the arithmetic processing of the device can reduce the degree of influence of the failure of the digital arithmetic means such as a microprocessor which has the most serious influence on the digital system. Therefore, it is possible to realize a digital reactor output monitoring device capable of realizing sufficient reliability and high-speed response even in a small reactor in which the detector output is shared.

Further, according to the reactor output monitoring apparatus of the second aspect, since the detector output branching means is composed of a circuit with an insulating function, the first and second apparatuses are electrically insulated and separated. ing. Therefore, even if one of the first device and the second device fails, the effect thereof is not transmitted to the other device through the detector output branching means, so that the redundant configuration is maintained. This makes it possible to further increase the reliability of operation.

According to the reactor output monitoring apparatus of the third aspect, when calibrating the detector output such as gain adjustment,
In the first device, which is the transmitter side of the detector output, a calibration value calculated by another calculation means outside the reactor output monitoring device (for example, the neutron flux distribution of the reactor is calculated, and The value calculated by comparing the neutron flux intensity at the detector position with the current detector output) is used as is, but in the second device on the receiving side, after the calibration actually obtained by the first device The calibration coefficient is calculated based on the ratio of the detector output of the above-mentioned detector output to the detector output before the calibration supplied from the detector output branching means, and the calibration process using the calculated calibration coefficient is performed.

Since the output paths of the detectors on the transmitting side and the receiving side are different, if the same calibration coefficient as that on the transmitting side is used on the receiving side, a difference in conversion coefficient (for example, a difference in offset or gain in the analog / digital conversion means, In some cases, it may not be possible to obtain an accurate reactor output due to signal transmission loss, etc.).

However, as described above, by calculating the value of the actual adjustment gain based on the ratio between the detector output after calibration and the detector output before calibration supplied from the detector output branching means, The gain on the receiving side can be determined so that the output on the receiving side matches the output on the transmitting side. For this reason, it is possible to eliminate the occurrence of an error due to a difference in conversion coefficient between the analog / digital converting means on the transmitting side and the receiving side, a loss in signal transmission, and the like, so that the output of the detector is accurately monitored in each of the two devices. It is possible to improve the reliability.

Further, according to the reactor output monitoring apparatus of the fourth aspect, the integrity of the circuit in the first device on the transmission side can be confirmed, and the circuit on the transmission side can be protected from a failure such as a short circuit between the electrodes of the detector. In the case of protection, the detector may be separated from the input means by the input switching means. In this case, the status signal from the input switching means informs the digital computing means on the receiving side of the status of the input means such as whether the input means of the transmitting side device is disconnected from the detector. Therefore, it is possible to prevent malfunction of the monitoring process in the receiving side device due to the monitoring of the output of the detector that is not monitored by the receiving side device.

Further, according to the reactor output monitoring apparatus of the fifth aspect, since it has both the configurations of the third aspect and the fourth aspect, an error due to a difference in conversion coefficient in the analog / digital converting means on the receiving side is caused. Can be eliminated and the reliability of the calibration process can be improved, and it is possible to prevent malfunction of the monitoring process in the receiving side device by monitoring the output of the unmonitored detector by the receiving side device. it can.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a basic configuration of a reactor output monitoring device according to an embodiment of the present invention. This reactor output monitoring device is a digital monitoring device with a redundant configuration in which a plurality of monitoring devices for monitoring the detector output of the neutron detector arranged in the reactor of a small reactor are redundantly arranged. In FIG. 1, only two of the plurality of devices 31, 32 are shown as representatives. These devices 31 and 32 each independently perform a monitoring operation, and even if one device fails, the other device can continue monitoring. Further, in order to improve the power supply fault tolerance, these devices are independently supplied with operating power from separate power supply circuits.

The basic structure of each of the devices 31 and 32 will be described below. The device 31 is a digital device that calculates the average value of the detection outputs of the neutron detectors 1a and 1b and monitors the output of the reactor based on the calculation result.
The detector signal input section 32, the signal branch output section 33, the analog / digital conversion section 34, the digital operation section 35, the gain input section 36, and the input switching section 38 are provided.

The neutron detectors 1a and 1b each output a current signal proportional to the intensity of the neutron flux incident on the detector. The detector signal input unit 32 converts the detector output from the corresponding neutron detectors 1a and 1b into current / voltage, and sends the detector output to the analog / digital converter 34 as an analog voltage signal.

The signal branch output unit 33 inputs the detection output of the neutron detector 1b in order to branch the detection output from the neutron detector 1b which is a common target with the device 32 and supply it to the device 32. It is provided in the subsequent stage of the detector signal input unit 32.

The signal branch output section 33 receives the voltage signal output from the detector signal input section 32 as an input, and outputs a voltage signal equivalent to the input signal and electrically isolated from the input signal. Output. Since the signal branch output unit 33 has such an insulating function, the device 31 and the device 32 are electrically isolated from each other. Therefore, even if one of the device 31 and the device 32 has a failure due to, for example, a power failure, the effect thereof is not transmitted to the other devices via the signal branch output unit 33, and thus the redundant configuration is adopted. It can be maintained, which makes it possible to increase the reliability of operation.

Further, even if external noise is added to the signal branched and output to the device 32, the value of the detector output supplied to the analog / digital conversion section 34 of the device 31 is not affected.

In such an insulation separation function, the signal branching output section 33 is constituted by an insulation amplifier, for example, an insulation amplifier using a transformer, an insulation amplifier using capacitor coupling, an optical insulation amplifier using an optical element, or the like. It can be realized by An isolation amplifier using a transformer is particularly excellent in terms of accuracy, and if it is used, highly accurate signal transmission can be performed.

The analog / digital converter 34 sequentially selects the detection outputs from the neutron detectors 1a and 1b and converts the selected detector output into a digital signal (binary number). This digital signal is sent to the digital arithmetic unit 35 with a built-in microprocessor.

The digital operation unit 35 is a neutron detector 1 by software processing executed by the microprocessor.
a and 1b, the neutron detector 1a from the calibration process for adjusting the gain of each detector output, and the calibration result.
And calculation processing such as processing for calculating the average output of the neutron detector 1b.

In this case, the gain adjustment is performed by the gain input unit 3
6 is carried out according to a predetermined calibration value inputted from an external arithmetic unit, and the reactor output% (detection of the detector signal output with respect to the neutron flux intensity at the reactor center when the reactor is producing the rated output) The result is calibrated to a value determined so as to be 100%.

The input switching unit 38 switches the input of the detector signal input unit 32, for example, when a test for confirming the soundness of the circuit in the device 31 is performed, and the detector 1
The detector signal input unit 32 is separated from a and 1b, and instead, a test input signal or the like for confirmation processing is input to the detector signal input unit 32. Further, even when the circuit of the device 31 is protected from a failure such as a short circuit between the electrodes of the detectors 1a and 1b, the input switching unit 38 causes the detector signal input unit 32 to operate.
Disconnect the fault detector from. A status signal indicating whether or not the detector has been disconnected is sent to the device 32 by the input switching unit 28.

The device 32 comprises a neutron detector 1c and a device 3
1 is a digital device that calculates the average value of the detection output of the neutron detector 1b that is shared with the neutron detector 1b and monitors the output of the reactor based on the calculation result. The digital converter 34 and the digital calculator 35 are provided.

That is, the neutron detector 1c outputs a current signal proportional to the intensity of the neutron flux incident on the detector. The detector signal input unit 32 of the device 32 converts the detector output from the neutron detector 1c into current / voltage, and sends the detector output to the analog / digital converter 34 as an analog voltage signal.

The analog-to-digital conversion unit 34 outputs the detector output of the neutron detector 1c input by the detector signal input unit 32 and the detector output of the neutron detector 1b supplied from the signal branch output unit 33 of the device 31. Are sequentially selected, and the selected detector output is converted into a digital signal (binary number).

The digital operation unit 35 uses the software processing executed by the microprocessor to execute the neutron detector 1
From the calibration process for adjusting the gain of the detector output of each of c and 1b, and the calibration result, the neutron detector 1c
And calculation processing such as processing for calculating the average output of the neutron detector 1b.

In this case, in the gain adjustment of the neutron detector 1b, the output of the neutron detector 1b after calibration and the signal branch output unit 3 which are obtained by the digital arithmetic unit 35 of the device 31.
The calibration coefficient is calculated based on the ratio to the output of the pre-calibration detector 1b supplied from No. 3, and the reactor output% is obtained by the calibration process using the calculated calibration coefficient. In addition, in the gain adjustment of the neutron detector 1c, the device 3
In the same manner as 1, the calibration process is performed using the calibration value corresponding to the detector 1c calculated by another calculation means outside the reactor power monitoring device.

The calibration result input unit 37 inputs the calibration result value of the neutron detector 1b from the digital operation unit 35 of the device 31, and supplies it to the digital operation unit 35 of the device 32.
The calibration result input unit 37 can be realized by, for example, a digital transmission device that transfers data between the devices 31 and 32 or a numerical value input device by an operator.

The status signal receiving section 39 receives the status signal transmitted from the input switching section 38 of the device 31, supplies it to the digital computing section 35, and digitally changes the status of the detector signal input section 32 of the device 31. The calculation unit 35 is notified.

Next, the basic operation of the reactor power monitoring system of FIG. 1 will be described. In the devices 31, 32, the neutron detectors 1a, 1b, 1c input by the detector signal input unit 32
The detector output from each is converted into a digital signal by each analog / digital conversion section 34, and is calculated by each digital calculation section 35. Also, the devices 31, 3
The detection output from the neutron detector 1b shared between the two is
At the signal branch output 33 of the device 31, it is taken out as an electrically insulated voltage signal and sent to the analog / digital converter 34 of the device 32.

In the calculation in the digital calculation section 35 of each of the devices 31 and 32, the detector output is adjusted in gain and converted into the reactor output%, and then the reactor output in each of the devices 31 and 32 is converted. Used to monitor.

As described above, regarding the detector output of the shared detector 1b, the analog output of the device 31 on the transmitting side is detected.
Before reaching the digital operation unit 35 via the digital conversion unit 34, the detector signal input unit 3 of the device 31 on the transmission side thereof.
The signal is branched by the signal branch output unit 33 provided at the latter stage of the second stage 2 and supplied to the input of the analog / digital conversion unit 34 of the device 32 on the receiving side.

Therefore, as shown in FIG. 2, the signal branch output unit 33 is provided in the detector output path of the shared neutron detector 1b as compared with the unshared detectors 1a and 1b. It only needs to be increased, and the number of devices existing in the shared detector output transmission path can be significantly reduced as compared with the case of using the conventional data transmission.

Since the failure rate of the apparatus is the sum of the failure rates of the constituent elements of the apparatus, the smaller the number of constituent elements, the higher the reliability. In particular, the fact that the shared detector output of the detector 1b is passed as an analog voltage signal to the receiving device 32 without passing through the arithmetic processing by the microprocessor of the device 31 has the most serious influence on the digital system. It is possible to reduce the degree of influence of the failure of the digital operation unit 35 such as a microprocessor.
Therefore, sufficient reliability and responsiveness can be realized even in a small reactor in which the detector output is shared.

Further, when the gain of the shared neutron detector 1b is adjusted, in the device 31 which is the source of the detector output, it is calculated by the calculation means outside the reactor output monitoring device (specifically, in the reactor The neutron flux distribution is calculated, and one is calculated for each neutron detector by comparing the neutron flux intensity at each detector position given from the result with the current detector output) Gain of detector is gained The device 32 on the side that receives the detector output as it is input by the input unit 36
Then, the reactor output% of the detector after gain adjustment at the transmission source is input by the calibration result input unit 37, and the analog output of the neutron detector 1b supplied from the signal branch output unit 33 The gain of the detector 1b is calculated by dividing by the digital conversion result. Then, the reactor output% of the detector 1b is obtained from the calculated gain.

Since the output path of the detector 1b is different between the transmission side and the reception side, if the same calibration coefficient as that at the transmission side is used at the reception side, a difference in conversion coefficient (for example, a difference in offset or gain in analog / digital conversion means). However, it may not be possible to obtain an accurate reactor output due to signal transmission loss, etc.).

However, as described above, the actual value of the adjustment gain is calculated based on the ratio of the detector output after calibration in the device 31 and the detector output before calibration supplied from the signal branch output unit 33. As a result, the gain on the receiving side can be determined so that the output on the receiving side matches the output on the transmitting side. Therefore, it is possible to eliminate the occurrence of an error due to a difference in conversion coefficient between the analog / digital converting means 34 on the transmitting side and the receiving side, a signal transmission loss, and the like.
It is possible to accurately monitor the output of the detector 1b in each of 32.

Further, in the device 31 on the transmitting side, when the detector signal 1b is cut off to input the calibration signal in order to confirm the soundness of the circuit, or due to a failure such as a short circuit between the electrodes of the detector 1b, the device 31 is damaged. If the detector 1b is disconnected from the input section 32 to protect the circuit, the detector 1b will be removed for other reasons.
When b is excluded from the monitoring calculation (when the level of the detector signal is not monitored and the detector signal is not included in the average calculation for calculating the average power of the reactor) The input switching unit 38 causes the input unit 3
There is a case where the detector 1b is disconnected from the device 2. In this case, a signal indicating that the detector 1b is excluded from the monitoring calculation, such as whether or not the input unit 32 of the transmission side device 31 is separated from the detector 1b by the status signal from the input switching unit 38, is output. By being input to the receiving device 32,
The receiving side device 32 can also exclude the detector signal from the nuclear reactor monitoring calculation.

Furthermore, competing the state of the shared detector 1b with an analog voltage signal simplifies the circuit and improves reliability as compared with the case of data transmission, and the sending side device 3
It is possible to shorten the time required for the state change of 1 to be transmitted to the receiving side device 32, and to reduce the possibility of causing a state mismatch between the sending side and the receiving side.

FIG. 3 shows a concrete structure of the reactor output monitoring apparatus shown in FIG. 1, particularly a circuit structure around the input part of the neutron detector 1b. In the devices 31 and 32,
The detector signal input unit 32 of FIG. 1 is composed of a switch circuit 32a and a current / voltage conversion circuit 32b.
Further, the analog / digital conversion section 34 of FIG. 1 is configured by a signal selection circuit 34a and an analog / digital converter 35, and the input switching section 38 is a switch control circuit 38.
a, and the status signal receiving section 39 is composed of a contact signal input circuit 39a. Furthermore, device 3
A calibration signal generation circuit 44 is provided in each of 1 and 32.

The switch circuit 32a is a circuit for electrically opening and closing the circuit, and the opening and closing is performed by the switch control circuit 38a.
Done by The switch control circuit 38a includes a contact switch circuit and the like, and the contact state is switched by the switching operation thereof. Normally, the contact state of the switch control circuit 38a is closed, and at this time, a contact signal for opening the switch circuit 32a is output. Further, when the contact state of the switch control circuit 38a is set to the open state, the calibration signal generation circuit 44
Is transmitted to the current / voltage conversion circuit 32b via the switch circuit 32a, and a contact signal for closing the switch circuit 32a is output.

The current / voltage conversion circuit 32b receives the current signal from the detector as an input and outputs a voltage signal proportional to the current signal. The signal selection circuit 34a receives a plurality of voltage signals, selects one of them, and outputs it. The analog-digital converter 34b receives the analog voltage signal as an input and outputs a digital signal (binary number) proportional to the input signal. The contact signal input circuit 39a inputs a contact signal indicating the contact state of the switch control circuit 38a.

Next, the devices 31 and 3 configured as described above.
The operation of No. 2 will be described. First, processing of a detector signal (here, the output of the neutral detector 1c) that is not shared between the devices 31 and 32 will be described.

The current output signal of the neutron detector 1c is
The voltage signal is converted by the voltage conversion circuit 32b, selected by the signal selection circuit 34a, converted into a digital value by the analog / digital conversion circuit 34b, and the digital value is converted by the digital operation section 35 using a microprocessor. It is processed.

The processing of the detector signal (here, the output of the neutral detector 1b) shared between the devices 31 and 32 is as follows. The current output signal of the neutron detector 1b is converted into a voltage signal by the current / voltage conversion circuit 32b of the device 31 on the transmission side, is processed by the digital operation unit 35 of the device 31, and is electrically supplied from the signal branch output unit 33. Is output as a voltage signal isolated from the input signal and input to the signal selection circuit 34a of the device 32 on the receiving side.

In the device 32 on the receiving side, the signal selection circuit 34
The output from the signal branch output unit 33 is selected by a and sent to the analog / digital converter 34b, where it is converted into a digital value. This digital value is the device 32
The digital arithmetic unit 35 performs the arithmetic processing.

Next, the processing for adjusting the gain of the detector will be described. When adjusting the gain of the detector 1b, the device 3 on the transmission side
In No. 1, a new gain is input from the gain input section 36 by online or operation of the operator, and the gain used in the digital calculation section 35 is changed to the new gain. On the other hand, in the device 32 on the receiving side, the gain of the shared detector 1b is the value S of the reactor output% of the detector 1b after the gain adjustment in the device 31 is received online or by operating the operator. Calibration result input unit 3 of the side device 32
7 and the value of the reactor output% of the detector after gain adjustment is divided by the digital value T of the analog-digital conversion result of the detector 1b output in the receiving side device 32 in the digital operation unit 35 The gain G is determined.

G = S / T (1) Then, by multiplying the gain G by the digital value T of the analog-digital conversion result of the detector 1b output,
The calibration result T'is obtained.

T ′ = G · T (2) Next, the process at the time of circuit calibration will be described. Device 31 on the sending side
In the current / voltage conversion circuit 32b, the signal selection circuit 3
4a and the analog-to-digital conversion circuit 34b, the switch control circuit 38a is set to a state for inputting the output of the calibration signal generating circuit 44, and at this time, the switch control circuit 38a outputs the output. The switch circuit 32a is closed by the contact signal. As a result, the detection output of the neutron detector 1b is disconnected from the current / voltage conversion circuit 32b, and the calibration signal from the calibration signal generation circuit 44 is input instead.

The state of the switch control circuit 38a is input by the contact signal input circuit 39a of the receiving side device 32, the detection output of the neutron detector 1b is disconnected, and the calibration signal is input instead. The digital calculation unit 35 of the reception side device 32 is notified. The digital arithmetic unit 35 is
The output of the detector 1b is excluded from the monitoring calculation, and the calibration signal supplied from the signal branch output unit 33 is used, and the current / voltage conversion circuit 32b, the signal branch output unit 33, and the reception device 32 of the transmission side device 31 are used. The operation of the signal selection circuit 34a and the analog / digital conversion circuit 34b is checked.

Next, the operation of excluding the neutron detector 1b from the monitoring target due to a failure of the neutron detector 1b will be described. Also in this case, the transmitting device 3
In No. 1, the switch circuit 32a is closed by the signal from the switch control circuit 38a. As a result, the detection output of the neutron detector 1b is disconnected from the current / voltage conversion circuit 32b. The state of the switch control circuit 38a at this time is input by the contact signal input circuit 39a of the reception side device 32, and the digital calculation unit 35 of the reception side device 32 is notified that the detection output of the neutron detector 1b is disconnected. It The digital calculation unit 35 excludes the output of the detector 1b from the monitoring calculation.

Here, the response speed of the reactor power monitoring system of FIG. 3 will be considered. Assuming that the response time of each component of the devices 31 and 32 is Tn (n: component number), the total response time Ttotal required for the receiving device 32 to process the detector output of the detector 1b is It becomes like. However, here, for simplicity, only the signal path in the normal monitoring state is considered.

Ttotal = T32a + T32b + T33 + T34a + T34b On the other hand, in the case of performing data transfer using the data transmission circuit K and the data reception circuit L indicated by broken lines in the figure, as in the conventional case, the shared detector 1b The total response time Ttotal 'on the receiving side is as follows.

Ttotal '= T32a + T32b + T34a + T
34b + T35 + Tk + TL When Ttotal and Ttotal 'are compared, Ttotal'-Ttotal = T35 + Tk + TL-T33 (>
0).

That is, the total response time of the data transmitting / receiving circuits K and L and the arithmetic unit 35 using a microprocessor is compared with the response time of the signal branch input unit 33. In general, a circuit that processes complicated functions such as data transmission / reception and calculation using a microprocessor using software has a simpler function like the hardware logic configuring the signal branch input unit 33. The response time is longer than that of a circuit that does not use soft air. Therefore, in the case of the embodiment, the total response time on the receiving side of the shared detector 1b is smaller and the response time is faster than in the case of using data transmission.

Next, referring to FIG. 4, the neutron detector 1b
To exclude the neutron detector 1b from the monitoring target due to failure of the device from the device 31 on the transmitting side to the device 32 on the receiving side.
Another configuration for notifying the user will be described.

That is, in FIG. 4, the switch circuit 32a 'interlocking with the switch circuit 32a further includes the device 3
1, the switch circuit 32a is set to the open state when the switch circuit 32a is set to the open state by the switch control circuit 38b for disconnecting the neutron detector 1b. At this time, the switch circuit 32a 'is
It is connected to a reference voltage supply terminal set to a voltage value outside the normal measurement range, and the reference voltage signal is sent to the device 32 via the signal branch output unit 33. In the device 32, the reference voltage signal is sent to the digital arithmetic unit 34 via the signal selection circuit 34a and the analog-digital conversion circuit 34b, thereby notifying that the neutron detector 1b is excluded from the monitoring target.

In this configuration, by setting the signal after current-voltage conversion to a value outside the normal measurement range, even if the state of the switch circuit 32a is not detected, the detector 1b is in the bypass state from the value of the measurement value itself. In other words, the fact that it has been excluded from the monitoring target is calculated by the digital operation units 3
It becomes possible to judge with 5.

[0081]

As described above, according to the present invention, a common neutron detector that is not shared in the path through which the detector output of the shared neutron detector reaches the digital arithmetic means of the receiving side device Only more circuits for signal branching are required compared to the case of the detector output, and the number of devices existing in the shared detector output transmission path is significantly reduced as compared with the case of using the data transmission. it can. Therefore,
Sufficient reliability and responsiveness can be realized even in a small reactor in which the detector output is shared.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a reactor output monitoring device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a transmission path of a detector output in the reactor output monitoring system of the embodiment.

FIG. 3 is a diagram showing a more specific circuit configuration of the reactor output monitoring apparatus according to the embodiment.

4 is a diagram showing a circuit configuration for bypass notification provided in the reactor power monitoring system of FIG.

FIG. 5 is a diagram showing a configuration of a conventional analog-type reactor output monitoring device.

FIG. 6 is a diagram showing a configuration of a conventional digital reactor output monitoring device.

FIG. 7 is a diagram showing a transmission path of a detector output in a conventional digital reactor output monitoring device.

[Explanation of symbols]

1a, 1b, 1c ... Neutron detector, 32 ... Detection signal input section, 32a ... Switch circuit, 32b ... Current / voltage conversion circuit, 33 ... Signal branch output section, 34 ... Analog / digital conversion section, 34a ... Signal selection circuit , 34b ... Analog / digital conversion circuit, 35 ... Digital operation section, 36 ... Gain input section, 38 ... Input switching section, 38a ... Switch control circuit, 39 ... Status signal receiving section.

Claims (5)

[Claims] 1. An input unit for inputting an output of a neutron detector installed in a nuclear reactor core, and an analog unit for converting a detector output input by the input unit into a digital value.
Redundant circuits each having digital conversion means and digital calculation means for processing the digital value corresponding to the detector output output from the analog / digital conversion means to monitor the reactor output of the reactor. A plurality of monitoring devices, wherein the first device in the monitoring devices is configured to share a given neutron detector at least between the first and second devices by transmitting a detector output to the second device. In the nuclear reactor output monitoring device, the detector output of the shared object detector, which is provided after the input unit of the first device and is output from the input unit, is branched to perform analog-digital conversion of the second device. A reactor output monitoring device comprising detector output branching means for supplying the input of the means. 2. The detector output branching means comprises a circuit with an insulation function in which the input and the output are electrically isolated from each other, and the output from the input means is inputted as an input voltage signal, and the input voltage signal is inputted. The reactor output monitoring device according to claim 1, wherein the reactor output monitoring device outputs an output voltage signal that is equivalent to the input voltage signal and is electrically insulated from the input voltage signal. 3. An input means for inputting the output of a neutron detector installed in the reactor core, and an analog converter for converting the detector output input by this input means into a digital value.
Redundant circuits each having digital conversion means and digital calculation means for processing the digital value corresponding to the detector output output from the analog / digital conversion means to monitor the reactor output of the reactor. A plurality of monitoring devices, wherein the first device in the monitoring devices is configured to share a given neutron detector at least between the first and second devices by transmitting a detector output to the second device. In the nuclear reactor output monitoring device, the detector output of the shared object detector, which is provided after the input unit of the first device and is output from the input unit, is branched to perform analog-digital conversion of the second device. Detector output branching means to be supplied to the input of the means, and a calibration coefficient of the detector output provided in the first device and corresponding to the shared object detector, input from the outside Means for calibrating the value of the detector output of the shared object detector using the input calibration coefficient, and a calibrated detector output provided in the second device and calibrated by the first device, A calibration coefficient corresponding to the shared target detector is calculated based on a ratio with the uncalibrated detector output supplied from the detector output branching means, and the shared target detector is utilized by using the calculated calibration coefficient. And a means for calibrating the value of the detector output of the reactor. 4. Input means for inputting the output of a neutron detector installed in the reactor core, and an analog converter for converting the detector output input by this input means into a digital value.
Redundant circuits each having digital conversion means and digital calculation means for processing the digital value corresponding to the detector output output from the analog / digital conversion means to monitor the reactor output of the reactor. A plurality of monitoring devices, wherein the first device in the monitoring devices is configured to share a given neutron detector at least between the first and second devices by transmitting a detector output to the second device. In the nuclear reactor output monitoring device, the output of the shared object detector, which is provided in the latter stage of the input unit of the first device and is output from the input unit, is branched to obtain the analog-digital conversion unit of the second device. A detector output branching means for supplying an input and a detector output of the shared object detector provided in the first device and separated from the input means of the first device. An input switching means for excluding the detector output from the monitoring target; and a receiving side device, which is provided in the second device, receives the status signal from the input switching means, and receives the status of the input means provided in the transmitting side device. And means for notifying the digital operation means of 1. 5. An input unit for inputting an output of a neutron detector installed in a reactor core, and an analog unit for converting a detector output input by the input unit into a digital value.
Redundant circuits each having digital conversion means and digital calculation means for processing the digital value corresponding to the detector output output from the analog / digital conversion means to monitor the reactor output of the reactor. A plurality of monitoring devices, wherein the first device in the monitoring devices is configured to share a given neutron detector at least between the first and second devices by transmitting a detector output to the second device. In the nuclear reactor output monitoring device, the output of the shared object detector, which is provided in the latter stage of the input unit of the first device and is output from the input unit, is branched to obtain the analog-digital conversion unit of the second device. A detector output branching means for supplying the input, and a calibration coefficient of the detector output provided in the first device, the detector output corresponding to the shared object detector, A means for calibrating the value of the detector output of the shared object detector using the input calibration coefficient; a calibrated detector output calibrated by the first device and calibrated by the first device; and the detection A calibration coefficient corresponding to the shared object detector based on the ratio to the detector output before calibration supplied from the instrument output branching means, and detection of the shared object detector using the calculated calibration coefficient For calibrating the value of the detector output and the first device, the input switching for separating the detector output of the shared target detector from the input means of the first device and excluding the detector output from the monitoring target Means and means for receiving a status signal from the input switching means and for notifying the status of the input means provided to the transmission side apparatus to the digital calculation means of the reception side apparatus, the means being provided in the second apparatus. To do Reactor power monitoring device according to symptoms.