JP2011137770A - Process measuring apparatus with radiation exposure doze measuring function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reporting simply beforehand a lifetime by exposure to a radiation of a process measuring apparatus, so as to prevent a failure or deterioration of measurement accuracy exceeding an allowance caused by accumulation of exposure to the radiation of the process measuring apparatus for a nuclear power plant. <P>SOLUTION: This process measuring apparatus for measuring a process amount of the nuclear power plant includes a process measuring circuit for measuring the process amount, a radiation exposure doze detection circuit for detecting a radiation exposure doze, a signal conversion circuit for performing conversion processing of a signal, and an exposure doze display circuit for displaying the radiation exposure doze. An exposed radiation doze of the process measuring circuit is detected by the radiation exposure doze detection circuit, and an output signal from the radiation exposure doze detection circuit is converted into a signal for displaying the radiation exposure doze by the signal conversion circuit, and the radiation exposure doze of the process measuring apparatus is displayed by the exposure doze display circuit according to the converted signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to maintenance of process measurement equipment used in a radiation environment.

When operating a nuclear power plant, it is necessary to measure various process quantities (pressure, temperature, flow rate, etc.) related to the nuclear power plant. Although these are generally referred to as process measurement devices, many of these process measurement devices for nuclear power plants are exposed to radiation. The tolerance of process measurement equipment to this radiation exposure has changed over time. Conventional process measurement equipment is mainly composed of a relatively large element-shaped bipolar element compared to the present, and is often composed of an analog circuit that allows a relatively large current to flow. Met. However, field-effect transistors (MOSFETs: Metal Oxide Insulator Semiconductor Field Effect Transistors, hereinafter abbreviated as MOSFETs) are becoming synonymous with MISFET: Metal Insulator Semiconductor Field Effect Transistors. The digital IC using the word) has come to be used a lot. In addition, MOSFETs used in digital ICs with the times have become more susceptible to radiation due to the increase in speed and miniaturization of element shapes, the reduction in gate oxide thickness, and the like. For this reason, it is predicted that the resistance of the process measurement device to radiation will further decrease, which is a serious problem.
On the other hand, the operation of nuclear power plants is in the direction of prolonging each operation cycle. Accordingly, the setting of the preventive maintenance time by replacing each process measuring device is increasingly shortened, and the maintenance cost is expected to increase.
A radiation exposure measuring device is disclosed in Patent Document 1. However, it was a measuring device of the measurement location and the exposure dose at that time, and the accumulated value of radiation was unknown and it was a large device.

JP-A-6-109850

There is a problem that the process measurement equipment for nuclear power plants should not break down due to the accumulation of radiation exposure or cause the measurement accuracy to fall beyond the allowable limit.
Therefore, the present invention solves such problems, and an object of the present invention is to provide a method for easily and beforehand informing the lifetime of a measurement function due to radiation exposure of a process measurement device. .

In order to solve the above-described problems and achieve the object of the present invention, the present invention is configured as follows.
That is, in a process measurement device that measures a process amount of a nuclear power plant, a process measurement circuit that measures the process amount, a radiation exposure amount detection circuit that detects a radiation exposure amount, a signal conversion circuit that converts a signal, An exposure dose display circuit for displaying the radiation exposure dose, the radiation exposure dose detection circuit detects the radiation dose exposed by the process measurement circuit, and an output signal of the radiation exposure dose detection circuit is output by the signal conversion circuit. The radiation exposure dose is converted into a signal for display, and the exposure dose display circuit displays the radiation exposure dose of the process measurement device based on the converted signal.

  With this configuration, the exposure amount display circuit displays the exposure status of the process measurement circuit in real time.

  Also, in process measurement equipment that measures the process amount of a nuclear power plant, a digital processing circuit is built in, a process measurement circuit that measures the process amount, a radiation exposure detection circuit that detects the radiation exposure, and a signal conversion process A signal conversion circuit, an exposure dose display circuit for displaying the radiation exposure dose, and an alarm output circuit for warning that the exposure dose has exceeded a predetermined threshold, the radiation dose exposed by the process measurement circuit being The radiation exposure detection circuit detects, the output signal of the radiation exposure detection circuit is converted into a digital signal by the signal conversion circuit, and the digital signal is converted into the radiation dose by a digital processing circuit built in the process measurement circuit. Is converted into a signal for displaying the exposure dose and a signal for warning that the exposure dose exceeds a predetermined threshold, and the converted signal The exposure amount display circuit displays the radiation exposure of the process measurement instruments, and the alarm output circuit to an alarm output.

  With this configuration, the radiation dose display circuit displays the radiation exposure status of the process measurement circuit, and the alarm output circuit outputs an alarm.

  ADVANTAGE OF THE INVENTION According to this invention, the method of notifying the lifetime of the measurement function by the radiation exposure of a process measurement apparatus in advance and simply can be provided.

It is a figure which shows the 1st schematic function structure of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention. It is a figure which shows the 2nd schematic function structure of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention. It is a figure which shows the 3rd schematic function structure of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention. It is a figure which shows the 4th schematic functional structure of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention. It is a figure which shows the 5th schematic function structure of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention. It is a figure which shows the 6th schematic function structure of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention. It is a figure which shows the rough functional structure of the process measurement circuit of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention. It is a circuit diagram of the 1st circuit example which shows the operation principle of the radiation exposure amount detection circuit of the process measurement apparatus with a radiation exposure amount measurement function which is embodiment of this invention. It is a circuit diagram of the 2nd circuit example which shows the operation principle of the radiation exposure amount detection circuit of the process measurement apparatus with a radiation exposure amount measurement function which is embodiment of this invention. It is a circuit diagram of the 3rd circuit example which shows the operation principle of the radiation exposure detection circuit of the process measurement apparatus with a radiation exposure measurement function which is embodiment of this invention. It is a circuit diagram of the 4th circuit example which shows the principle of operation of the radiation exposure detection circuit of the process measurement apparatus with a radiation exposure measurement function which is an embodiment of the present invention. It is a block diagram which shows an example of a structure of the signal conversion circuit of the process measurement apparatus with a radiation exposure dose measurement function which is embodiment of this invention.

Embodiments of the present invention will be described below.
(First embodiment (part 1))
FIG. 1 is a functional block diagram showing a first embodiment of the present invention. The inside of the broken line is the process measurement device 1 with a radiation exposure measurement function of the present embodiment. The process measurement device 1 with a radiation exposure measurement function includes a process measurement circuit 11, a radiation exposure detection circuit 12, a signal conversion circuit 13, and an exposure display circuit 14.
The process measurement circuit 11 is a circuit that measures various process amounts (flow rate, pressure, temperature, etc.) when operating a nuclear power plant. The radiation exposure detection circuit 12 includes an element that is affected when exposed to radiation, and outputs a change in circuit characteristics due to the radiation exposure as an electrical signal. The signal conversion circuit 13 receives the output signal from the radiation exposure detection circuit 12 and performs signal conversion processing on the output signal so that the exposure display circuit 14 can display information on the exposure dose. The exposure dose display circuit 14 receives the output signal of the signal conversion circuit 13 and displays information related to the exposure dose.

  Next, in order to describe the process measurement device 1 with the radiation exposure measurement function in more detail, first, the process measurement circuit 11, the radiation exposure detection circuit 12, the signal conversion circuit 13, and the exposure display that constitute the process measurement device 1 are included. Details of the circuit 14 will be described in order. Then, the whole process measurement apparatus 1 with a radiation exposure dose measuring function of the 1st Embodiment of this invention is demonstrated again.

(Process measurement circuit)
Process measurement when operating a nuclear power plant is generally performed as follows. The physical quantity of the process is converted into an electric quantity through the detection element based on various measurement principles. The quantity of electricity is digitized by an analog-digital conversion circuit (A / D conversion circuit, ADC: Analog Digital Converter, hereinafter also abbreviated as A / D conversion circuit), and the like, and is processed by a digital processing circuit such as a processor. Arithmetic processing is performed and the result is output.

FIG. 7 shows an example of the configuration of the process measurement circuit 11. The physical quantity detection element 111 is an element that detects various process quantities (flow rate, pressure, temperature, etc.) when operating the nuclear power plant. The physical information of the process quantity detected by the physical quantity detection element 111 is converted into an electrical signal by the physical quantity detection circuit 112. This electrical signal is converted into an electrical signal of a digital signal by an A / D conversion circuit 116 and sent to a digital processing circuit 113. The digital processing circuit 113 performs arithmetic processing on the physical information of the process amount into a desired form, for example, a real-time value, a cumulative value, or a change amount of the process amount, and outputs a signal to the analog output circuit 114 or the digital output circuit 115. In the process measurement circuit 11, there may be provided a device for displaying the process measurement analog output signal of the analog output circuit 114 and the process measurement digital output signal 122 of the digital output circuit 115 to display the process amount.
Note that the process measurement analog output signal 121 of the analog output circuit 114 has a standard process measurement value of 4 to 20 mA for current and 1 to 5 V for voltage.

  In addition, the process measurement circuit 11, and further, the physical quantity detection element 111, the physical quantity detection circuit 112, the digital processing circuit 113, the analog output circuit 114, the digital output circuit 115, and the A / D conversion circuit 116 incorporated therein are Since it is installed in an environment where various process quantities are measured when a plant is operated, it may be exposed to radiation and may be damaged due to its effects. If the process measurement circuit 11 suddenly fails, the operation of the nuclear power plant is hindered. Therefore, the radiation exposure detection circuit 12 detects the influence of this radiation exposure to cope with it in advance.

(Radiation exposure detection circuit)
First, it will be described how a field effect transistor (MOSFET) or bipolar transistor, which is a device element used in the process measurement circuit 11, is affected by radiation and changes the circuit characteristics.
FIG. 8 shows a basic structure of an operational amplifier (circuit) 200 having a MOSFET. The source of the P-type MOSFET 201 is connected to the positive power supply terminal 212, and the gate and drain are connected to each other and connected to the first terminal of the resistance element 209. The second terminal of the resistance element 209 is connected to the negative power supply terminal 211. The P-type MOSFET 201 and the resistance element 209 generate a bias voltage from the first terminal of the resistance element 209 that is the connection point.

  The source of the P-type MOSFET 202 is connected to the positive power supply terminal 212, and the gate is connected to the first terminal of the resistance element 209. For this reason, since the bias voltage is applied to the gate, the P-type MOSFET 202 operates at a constant current. The source of the P-type MOSFET 203 is connected to the drain of the P-type MOSFET 202, the gate is connected to the first input terminal 213, and the drain is connected to the drain of the N-type MOSFET 206. The source of the N-type MOSFET 206 is connected to the negative power supply terminal 211, and the gate and drain are connected to each other. The source of the P-type MOSFET 204 is connected to the drain of the P-type MOSFET 202, the gate is connected to the second input terminal 214, and the drain is connected to the drain of the N-type MOSFET 207. The source of the N-type MOSFET 207 is connected to the negative power supply terminal 211, and the gate is connected to the gate of the N-type MOSFET 206. The series circuit of the P-type MOSFET 203 and the N-type MOSFET 206 and the series circuit of the P-type MOSFET 204 and the N-type MOSFET 207 form a differential pair, and the potential difference between the first input terminal 213 and the second input terminal 214 is that of the N-type MOSFET 207. Output from the drain.

  The source of the P-type MOSFET 205 is connected to the positive power supply terminal 212, the gate is connected to the first terminal of the resistance element 209, and the drain is connected to the drain of the N-type MOSFET 208. The source of the N-type MOSFET 208 is connected to the negative power supply terminal 211, the gate is connected to the drain of the N-type MOSFET 207, and the drain is an output terminal 215 as the operational amplifier 200. The P-type MOSFET 205 and the N-type MOSFET 208 are a level shift circuit that corrects the output signal of the drain of the N-type MOSFET 207, which is the output of the differential pair, under an appropriate bias voltage, an amplification circuit that amplifies the output signal, It also serves as a role.

  Assume that the above operational amplifier was exposed to radiation. Radiation is composed of alpha rays (α rays), beta rays (β rays), and gamma rays (γ rays), but α rays and γ rays are likely to affect process measurement circuits in nuclear power plants. Alpha rays are particles consisting of two protons and two neutrons, and have a strong ionization effect but a low transmission power. In addition, gamma rays are electromagnetic waves with high energy, so that the transmission power is strong, but the ionization effect is weak. Therefore, depending on the situation, the method of influence is not unclear, but if charge is generated and accumulated in an oxide film or the like in the vicinity of the device element of a MOSFET or bipolar transistor, the driving ability and amplification factor of the device element decrease. It is also known to cause a leak phenomenon.

In FIG. 8, assuming that MOSFETs 201 to 208 are exposed to radiation to cause a reduction in driving capability and a leak phenomenon, the way of influence as a circuit is different.
Since the P-type MOSFET 203 and the P-type MOSFET 204 have a symmetric configuration and form a differential pair, even if the P-type MOSFET 203 and the P-type MOSFET 204 are exposed to radiation in the same manner and their characteristics change. If the influence is similar, the characteristic change is canceled out and does not appear on the surface. Similarly, the N-type MOSFET 206 and the N-type MOSFET 207 have a symmetric configuration and form a differential pair. Therefore, the N-type MOSFET 206 and the P-type MOSFET 207 are exposed to radiation in the same manner, and their characteristics change. However, if the influence is the same, the characteristic change is canceled out and does not appear on the surface.

On the other hand, when the P-type MOSFETs 201, 202, and 205 and the N-type MOSFET 208 are exposed to radiation and each of them undergoes a change in characteristics, there is nothing that cancels out the influence, so that the characteristics as the operational amplifier 200 change. The degree of characteristic change varies depending on the circuit configuration, the material and structure of the device element, the occupied area, the relationship with surrounding elements, and the like.
FIG. 8 is a circuit used to explain the influence and operation of the operational amplifier 200 when exposed to radiation, but can also be used as the radiation exposure detection circuit 12.

  FIG. 9 is a circuit diagram showing an example of the simplest class of radiation exposure detection circuit 12. It consists of a P-type MOSFET 301 and a resistance element 302. The source of the P-type MOSFET 301 is connected to the positive power supply terminal 212, the gate is connected to the input terminal 314, and the drain is connected to the first terminal of the resistance element 302. The second terminal of the resistance element 302 is connected to the negative power supply terminal 311. A connection point between the drain of the P-type MOSFET 301 and the first terminal of the resistance element 302 is an output terminal 315 as the radiation exposure detection circuit 12. An appropriate potential necessary for a desired operation is applied to the input terminal 314 of the gate of the P-type MOSFET 301.

At this time, if the P-type MOSFET 301 is exposed to radiation, as described above, the driving ability is reduced and the leakage phenomenon occurs. The output potential of the output terminal 315 as the radiation exposure detection circuit 12 changes depending on the exposure status (exposure dose, accumulated time, etc.). Therefore, the circuit shown in FIG. 9 can be used as the radiation exposure detection circuit 12 by using the output signal of the output terminal 315.
Note that the sensitivity of the radiation exposure detection circuit 12 can be changed by changing the potential of the input terminal 314 which is the gate of the P-type MOSFET 301. Further, by applying a negative potential (311) or a positive potential (312) to the input terminal 314, the radiation exposure detection circuit 12 can be used as a switch for turning on or off.

  FIG. 10 shows a radiation exposure detection circuit 12 using a bipolar transistor 401. It consists of an NPN bipolar transistor 401 and a resistance element 402. The emitter of the NPN bipolar transistor 401 is connected to the negative power supply terminal 411, the base is connected to the input terminal 414, and the collector is connected to the first terminal of the resistance element 402. A second terminal of the resistance element 402 is connected to a positive power supply terminal 412. A connection point between the collector of the NPN bipolar transistor 401 and the first terminal of the resistance element 402 is an output terminal 415 as the radiation exposure detection circuit 12. Further, an appropriate potential necessary for a desired operation is applied to the input terminal 414 at the base of the NPN bipolar transistor 401.

At this time, if the NPN bipolar transistor 401 is exposed to radiation, as described above, a decrease in current gain and a leakage phenomenon occur. The output potential of the output terminal 415 as the radiation exposure detection circuit 12 changes depending on the exposure status (exposure, accumulated time, etc.). Therefore, the circuit shown in FIG. 10 can be used as the radiation exposure detection circuit 12 by using the output signal of the output terminal 415.
Note that the sensitivity of the radiation exposure detection circuit 12 can be adjusted by changing the potential of the input terminal 414 that is the base of the NPN bipolar transistor 401. Further, by applying a positive potential (412) or a negative potential (411) to the input terminal 414, the radiation exposure detection circuit 12 can be used as a switch for turning on or off.

  FIG. 11 shows a schematic configuration of a circuit when an operational amplifier 501 using bipolar is tested for a characteristic change caused by radiation exposure. The power of the operational amplifier 501 is supplied by a positive power supply terminal 512 and a negative power supply terminal 511. A constant voltage signal from a constant power supply circuit is connected to the first input terminal 513 of the operational amplifier 501, and the second input terminal 514 is connected to a connection point between the first terminal of the resistance element 504 and the first terminal of the resistance element 505. Yes. This connection point is the second output terminal 514B. The second terminal of the resistance element 504 is connected to the positive power supply terminal 512, and the second terminal of the resistance element 505 is connected to the negative power supply terminal 511. The first terminal of the resistance element 502 and the first terminal of the resistance element 503 are connected to form a first output terminal 515. The second terminal of the resistance element 502 is connected to the positive power supply terminal 512, and the second terminal of the resistance element 503 is connected to the negative power supply terminal 511.

The resistance elements 502, 503, 504, and 505 detect changes in the potential of the second input terminal 514 of the operational amplifier 501 by looking at voltage changes between the second output terminal 514B and the first output terminal 515. is there.
In the experiment, when the operational amplifier 501 was exposed to radiation, a voltage change was observed over time between the first output terminal 515 and the second output terminal 514B. Since the configuration of the operational amplifier 501 is a black box, it cannot be specified how the radiation exposure affected which device in the operational amplifier 501, but the characteristics of the operational amplifier 501 changed with the radiation exposure.

  As described above, the element used for the radiation exposure detection circuit 12 may be a MOSFET or a bipolar transistor. However, preferably, if the process measurement circuit 11 (FIG. 1) mainly uses a MOSFET, the radiation exposure detection circuit 12 reflects the actual situation when the MOSFET is used, and the process measurement circuit 11 (FIG. 1) is bipolar. If a transistor is mainly used, it is considered that the radiation exposure detection circuit 12 should be a bipolar transistor.

As mentioned above, although the example in which the characteristic of an electric circuit changes with radiation exposure in FIGS. 8-11 was shown, since even one MOSFET and a bipolar transistor are influenced, a normal electric circuit is fundamentally a radiation of radiation. The characteristics of the electric circuit change due to exposure. Therefore, various circuits other than the circuits shown in FIGS. 8 to 11 can also be used as the radiation exposure detection circuit 12.
In addition, MOSFETs and bipolar transistors have been described as elements whose characteristics change greatly due to radiation exposure. However, when the characteristics of device elements such as resistance elements and capacitors change due to radiation exposure, their characteristics are changed. The impact needs to be taken into account.
Also, for the reasons described above, the characteristics change from circuit to circuit even if the circuit is exposed to the same radiation. Depending on the circuit configuration, there are ones that are greatly affected by radiation exposure and those that are small. Therefore, when used as the radiation exposure detection circuit 12, it is necessary to grasp in advance the correlation between the radiation exposure and the circuit characteristic change. By grasping this correlation characteristic, the radiation exposure limit of the process measurement circuit 11 (FIG. 1) can be managed and appropriate measures can be taken.

(Signal conversion circuit)
FIG. 12 shows an example of the configuration of the signal conversion circuit 13. Since the output signal of the radiation exposure detection circuit 12 (FIG. 1) is generally an analog amount, the A / D conversion circuit 606 converts it into a digital signal that can be easily processed by an analog-digital conversion function. This digital signal is input to the logic circuit 607 and converted into a signal that can be easily displayed by the exposure display circuit 14 thereafter. Note that the logic circuit 607 may be implemented by a logic circuit in which hardware is fixed as described above, or may be implemented by software signal processing that can change functions flexibly. Software is easier to deal with function changes, but a logic circuit with fixed hardware has a smaller circuit scale, leading to cost reduction and miniaturization. Further, when the function of processing the digital signal is provided in another circuit, only the A / D conversion circuit 606 may be used. Further, the A / D conversion circuit 606 is not limited to a generally known full-scale analog-to-digital conversion having a high function, and a simple analog-to-one bit of about 1 to 2 bits depending on the application. A circuit having a digital conversion function may be used.

(Exposure level display circuit)
The exposure dose display circuit 14 (FIG. 1) outputs a signal indicating the radiation exposure dose in accordance with the signal output from the signal conversion circuit 13 (FIG. 1). Moreover, when the exposure dose display device is mounted on the process measurement device 1 with radiation exposure function (FIG. 1), the exposure dose is displayed on the exposure dose display device according to the signal output from the signal conversion circuit 13 (FIG. 1). indicate. The primary purpose of the displayed exposure dose is to display the cumulative exposure dose. However, the amount of change is calculated and stored, and the exposure dose for a certain period (month, week, day, time, etc.) is displayed. May be.

(First embodiment (part 2))
Although the individual functional blocks constituting the first embodiment of the present invention in FIG. 1 have been described above, the overall operation will be described again with reference to FIG.
In the process measurement device 1 with a radiation exposure function, a process measurement circuit 11 that measures various process amounts (flow rate, pressure, temperature, etc.) when operating a nuclear power plant and a radiation exposure detection circuit 12 are provided. It has been. Therefore, it is presumed that the radiation exposure detection circuit 12 is exposed to substantially the same amount of radiation exposed when the process measurement circuit 11 measures various process amounts. When the radiation exposure causes device elements represented by MOSFETs and bipolar transistors in the process measurement circuit 11 to deteriorate and changes in characteristics occur, the changes are caused by the MOSFETs and bipolar transistors in the radiation exposure detection circuit 12. The same occurs in the device element represented by the above, and as the radiation exposure detection circuit 12, a characteristic change occurs and the change is detected. The radiation exposure detection circuit 12 displays the radiation exposure by the signal processing circuit 13 and the exposure display circuit 14 through the characteristic change. Alternatively, the radiation exposure dose may be displayed by an external device (not shown) of the process measurement device 1 with the radiation exposure function by the exposure dose display output signal 123.

  The radiation exposure amount displayed by the exposure amount display circuit 14 is the one received by the radiation exposure amount detection circuit 12, but the radiation exposure amount detection circuit 12 and the process measurement circuit 11 are the same process measuring device 1 with a radiation exposure function. Therefore, it is assumed that the process measurement circuit 11 has also received the same radiation exposure. Therefore, the radiation exposure dose of the process measurement circuit 11 is determined based on the display of the exposure dose display circuit 14. If this display is exposed to a predetermined amount of radiation and the exposure dose is accumulated further, the manager of the nuclear power plant determines that the process measurement circuit 11 has failed or has reached a stage that deviates from an allowable measurement error. In this case, the administrator can replace the process measurement circuit 11 before the failure. The continuous operation of the nuclear power plant is possible by the auxiliary operation of a series of functions by the detection of the radiation exposure detection circuit 12, the signal conversion by the signal processing circuit 13, and the display of the exposure display circuit 14.

(Second Embodiment)
FIG. 2 is a functional block diagram showing a second embodiment of the present invention. The inside of the broken line is the process measuring device 1 with the radiation exposure measuring function of the present invention. The process measurement device 1 with a radiation exposure measurement function includes a process measurement circuit 11, a radiation exposure detection circuit 12, a signal conversion circuit 13, and an alarm output circuit 15.
The process measurement circuit 11 and the radiation exposure detection circuit 12 are the same as those in the first embodiment shown in FIG. The signal conversion circuit 13 is similar to the analog-decidal conversion of the signal from the radiation exposure detection circuit 12, but differs in that the subsequent digital signal is converted so that the alarm output circuit 15 operates. The alarm output circuit 15 receives the output signal of the signal conversion circuit 13 and outputs warning information regarding the accumulated radiation exposure as an alarm output signal 124.

In addition, when an alarm device is mounted on the process measuring device 1 with radiation exposure function, an alarm device (not shown) issues an alarm by the alarm output signal 124 of the alarm output circuit 15. This warning may mean a warning of a dangerous situation in which the accumulated radioactivity causes a failure for the process measurement circuit 11 and has not yet reached a dangerous situation in which a failure occurs. However, the radiation exposure amount is short-term. It may mean a warning such as when the value exceeds a predetermined value.
When the manager of the nuclear power plant makes a judgment based on this warning, the manager of the nuclear power plant can replace the process measuring device 1 with the radiation exposure measuring function or the process measuring circuit 11 before the failure. With the detection of the radiation exposure detection circuit 12, the signal conversion by the signal processing circuit 13, and the auxiliary operation of a series of functions by the warning of the alarm output circuit 15, the nuclear power plant can be continuously operated stably.

(Third embodiment)
FIG. 3 is a functional block diagram showing a third embodiment of the present invention. The inside of the broken line is the process measuring device 1 with the radiation exposure measuring function of the present invention. The process measurement device 1 with a radiation exposure measurement function includes a process measurement circuit 11, a radiation exposure detection circuit 12, a signal conversion circuit 13, an exposure display circuit 14, and an alarm output circuit 15.
The process measurement circuit 11, the radiation exposure detection circuit 12, and the exposure display circuit 14 are the same as those in the first embodiment shown in FIG. 1, and the alarm output circuit 15 is the second implementation shown in FIG. Since it is the same as that of a form, detailed description is abbreviate | omitted. The signal conversion circuit 13 in FIG. 3 is similar to analog-decidal conversion of the signal of the radiation exposure detection circuit 12, but the subsequent exposure signal display circuit 14 and the alarm output circuit 15 operate on the digital signal thereafter. It differs in that it converts the signal.

  Therefore, in FIG. 3, the dose display circuit 14 and the alarm output circuit 15 receive the output signal of the signal conversion circuit 13, respectively, and the dose display output signal 123, which is a display signal related to the accumulated radiation dose, Then, an alarm output signal 124 that outputs warning information is output. In addition, when the radiation exposure function function-equipped process measurement device 1 is equipped with an exposure dose display device and an alarm device, an exposure dose display device (not shown) is provided by an exposure dose display output signal 123 of the exposure dose display circuit 14. An alarm device (not shown) issues an alarm according to the alarm output signal 124 of the alarm output circuit 15. If the administrator of the nuclear power plant makes a judgment based on this display and warning, the administrator of the nuclear power plant may replace the process measuring device 1 with the radiation exposure measuring function or the process measuring circuit 11 before the failure. it can. The detection of the radiation exposure detection circuit 12, the signal conversion by the signal processing circuit 13, the display of the exposure display circuit 14, and the auxiliary operation of a series of functions by the warning of the alarm output circuit 15, continue the nuclear power plant. Thus, more stable operation is possible.

(Fourth embodiment)
FIG. 4 is a functional block diagram showing a fourth embodiment of the present invention. The inside of the broken line is the process measuring device 1 with the radiation exposure measuring function of the present invention. The process measurement device 1 with a radiation exposure measurement function includes a process measurement circuit 11, a radiation exposure detection circuit 12, a signal conversion circuit 13, an exposure display circuit 14, and an alarm output circuit 15.
Since the above configuration is the same as that of the third embodiment shown in FIG. 3, detailed description thereof is omitted. However, the difference from FIG. 3 is that the exposure dose display circuit 14 and the alarm output circuit 15 of FIG. 4 are integrated into an exposure dose display alarm circuit 16 having an exposure dose display function and an alarm output function. In this way, an integrated exposure amount display function and alarm output function are often convenient for the management of nuclear power plants.

(Fifth embodiment)
FIG. 5 is a functional block diagram showing a fifth embodiment of the present invention. The inside of the broken line is the process measuring device 1 with the radiation exposure measuring function of the present invention. The process measurement device 1 with a radiation exposure measurement function includes a process measurement circuit 11, a radiation exposure detection circuit 12, a signal conversion circuit 13, an exposure display circuit 14, and an alarm output circuit 15.
The process measurement circuit 11 and the radiation exposure detection circuit 12 are the same as those in the third embodiment shown in FIG.
The signal conversion circuit 13 in FIG. 5 is similar to analog-decidal conversion of the signal from the radiation exposure detection circuit 12, but the subsequent digital signal is sent to the digital processing circuit 113 (FIG. 7) in the process measurement circuit 11. It differs in that it is supplied.

The digital processing circuit 113 provided in the process measurement circuit 11 generally has a higher function than the function of the logic circuit 607 (FIG. 12) built in the signal conversion circuit 13 shown in FIG. Since there is, it performs signal conversion arithmetic processing with higher functionality. Based on the calculation result, the exposure amount display circuit 14 and the alarm output circuit 15 in FIG. 5 are driven. As a result, the functions of the exposure dose display circuit 14 and the alarm output circuit 15 are higher, and the function can be flexibly dealt with by changing the program.
Further, since the signal conversion circuit 13 in FIG. 5 has a function of only analog-decidal conversion of the signal from the radiation exposure detection circuit 12, the circuit scale can be reduced and the cost can be reduced.

(Sixth embodiment)
FIG. 6 is a functional block diagram showing a sixth embodiment of the present invention. The inside of the broken line is the process measuring device 1 with the radiation exposure measuring function of the present invention. The process measurement device 1 with a radiation exposure measurement function includes a process measurement circuit 11, a radiation exposure detection circuit 17 with a signal conversion function, an exposure display circuit 14, and an alarm output circuit 15.
The process measurement circuit 11, the exposure amount display circuit 14, and the alarm output circuit 15 are the same as those in the fifth embodiment shown in FIG.
The radiation exposure detection circuit 17 with a signal conversion function in FIG. 6 includes a simple analog-decidal conversion circuit (substantially equivalent to the A / D conversion circuit 606 in FIG. 12) in the radiation exposure detection circuit 12 in FIG. Is. Thus, the signal conversion circuit 13 in FIG. 5 is omitted. The overall function is the same as that of the circuit of FIG. 5, and the configuration of the circuits other than the process measurement circuit 11 is simplified, so that the circuit scale can be reduced and the cost can be reduced.

(Other embodiments)
In the above description, measurement of various process quantities (flow rate, pressure, temperature, etc.) in a nuclear power plant has been described as an example. However, the present invention can also be applied to process measurement equipment of facilities using nuclear power other than nuclear power plants.

  Further, although the measurement device is used, the present invention can be applied to a device whose life is shortened due to the influence of radiation in a facility related to nuclear power even if the purpose of the device is not measurement.

  Further, although the exposure amount display circuit 14 displays the accumulated exposure amount, it may display the recommended replacement time of the measuring device at the same time.

  As device elements, insulated gate field-effect transistors (MOSFETs) and bipolar transistors have been taken as examples. However, if the device used in the measuring instrument is another element, the radiation exposure detection circuit device can be used. It is desirable to use corresponding elements. For example, non-volatile memory elements such as IGBT (Insulated Gate Bipolar Transistor), HEMT (High Electron Mobility Transistor), or EEPROM (Electrically Erasable Programmable Read Only Memory), and ferroelectric memory elements such as FeRAM (Ferroelectric Random Access Memory) Is also a target.

  In the process measurement circuit 11, various device elements are included as a circuit configuration, and when it is unclear in advance which device element is most susceptible to radiation exposure, radiation exposure dose detection is performed. Two or more types of radiation exposure detection circuits 12 having different device configurations of the circuit 12 may be provided.

As described above, according to the embodiment of the present invention, it is possible to quantitatively monitor and evaluate the deterioration of the digital measuring device due to exposure, so that it is possible to realize maintenance by appropriate state monitoring.
In addition, more reliable monitoring can be performed by outputting an alarm.
In addition, this makes it possible to achieve high reliability and high economic efficiency for measuring instruments used in nuclear power plants.

  In nuclear power plants, facilities, equipment, etc., those that shorten the life of equipment such as measuring instruments due to the effects of radiation may be widely used and adopted.

DESCRIPTION OF SYMBOLS 1 Process measurement apparatus with a radiation exposure measurement function 11 Process measurement circuit 12, 17 Radiation exposure detection circuit 13 Signal conversion circuit 14 Exposure display circuit 15 Alarm output circuit 16 Exposure display alarm output circuit 111 Physical quantity detection element 112 Physical quantity detection circuit DESCRIPTION OF SYMBOLS 113 Digital processing circuit 114 Analog output circuit 115 Digital output circuit 116 A / D conversion circuit 121 Process measurement analog output signal 122 Process measurement digital output signal 123 Exposure amount display output signal 124 Alarm output signal 200,501 Operational amplifier 201,202,203, 204, 205, 301 P-type MOSFET
206, 207 N-type MOSFET
209, 302, 402, 502, 503, 504, 505 Resistance element 211, 311, 411, 511 Negative power supply terminal 212, 312, 412, 512 Positive power supply terminal 213, 214, 314, 414, 513, 514 Input terminal 215, 315, 415, 515, 514B Output terminal 414 Bipolar element

Claims (6)

In process measurement equipment that measures the process amount of a nuclear power plant,
A process measurement circuit for measuring the process amount;
A radiation exposure detection circuit for detecting the radiation exposure;
A signal conversion circuit for converting the signal;
An exposure dose display circuit for displaying the radiation exposure dose,
The radiation exposure detection circuit detects the radiation dose exposed by the process measurement circuit, the output signal of the radiation exposure detection circuit is converted into a signal indicating the radiation exposure by the signal conversion circuit, and the conversion A process measurement device with a radiation exposure dose measuring function, wherein the exposure dose display circuit displays a radiation exposure dose of the process measurement device based on a processed signal. An alarm output circuit for outputting an alarm when the exposure dose exceeds a predetermined threshold;
The radiation exposure detection circuit detects the radiation dose exposed by the process measurement circuit, the output signal of the radiation exposure detection circuit is converted by the signal conversion circuit, and the warning output circuit is generated by the converted signal. 2. The process measurement device with a radiation exposure measurement function according to claim 1, wherein an alarm is output when a radiation exposure dose of the process measurement device exceeds a predetermined threshold value set in advance. In process measurement equipment that measures the process amount of a nuclear power plant,
Built-in digital processing circuit, process measurement circuit to measure the process amount,
A radiation exposure detection circuit for detecting the radiation exposure;
A signal conversion circuit for converting the signal;
An exposure dose display circuit for displaying the radiation exposure dose,
The radiation exposure detection circuit detects the radiation dose exposed by the process measurement circuit, the output signal of the radiation exposure detection circuit is converted into a digital signal by the signal conversion circuit, and the digital signal is input to the process measurement circuit. Conversion processing into a signal for displaying the radiation exposure dose by a built-in digital processing circuit, and the exposure display circuit displays the radiation exposure dose of the process measurement device based on the converted signal. Process measurement equipment with radiation exposure measurement function. In process measurement equipment that measures the process amount of a nuclear power plant,
Built-in digital processing circuit, process measurement circuit to measure the process amount,
A radiation exposure detection circuit for detecting the radiation exposure;
A signal conversion circuit for converting the signal;
An exposure amount display circuit for displaying the radiation exposure amount;
An alarm output circuit for alarming a state in which the exposure dose exceeds a predetermined threshold,
The radiation exposure detection circuit detects the radiation dose exposed by the process measurement circuit, the output signal of the radiation exposure detection circuit is converted into a digital signal by the signal conversion circuit, and the digital signal is input to the process measurement circuit. Conversion processing into a signal for displaying the radiation exposure dose and a signal for warning that the exposure dose exceeds a predetermined threshold by a built-in digital processing circuit, and the exposure display circuit based on the converted signal Displays the radiation exposure dose of the process measurement device, and the warning output circuit outputs a warning output.   5. The process measurement apparatus with a radiation exposure measurement function according to claim 1, wherein the radiation exposure detection circuit and the process measurement circuit include an insulated gate field effect transistor. .   5. The process measurement apparatus with a radiation exposure measurement function according to claim 1, wherein a bipolar transistor is provided in the radiation exposure detection circuit and the process measurement circuit. 6.

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