JPH02226095A - Digital monitor for radiation beam - Google Patents

Abstract

PURPOSE:To improve a reliability of a whole device by performing an additional function of CPU and a signal transfer through an optical bus during a waiting time of a main CPU, and by avoiding an influence of major function treatment of the main CPU when the main CPU is under an abnormal condition. CONSTITUTION:A main CPU 11 executes a measure 30 of an additional function treatment after completion of a main function treatment. This measure 30 of the additional function treatment performs additional function of CPU 31 to 33 and a signal transfer through an optical bus during a waiting time of the main CPU. However, when the additional function CPU 31 to 33 themselves are under an abnormal condition, a fuse 37 is molten by the CPU themselves to cut off the CPU from a system bus 12, and also the main CPU 11 executes a time-up treatment to shift the main CPU into an original main function treatment, when a time predetermined by the additional function treatment, elapses, and therewith an influence of the additional function against the main function treatment is avoided. With those procedures, a reliability of whole device can be well confirmed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a digital radiation monitor device used in a nuclear power plant, and in particular, the present invention relates to a digital radiation monitor device used in a nuclear power plant. The present invention relates to a digital radiation monitor device that is not affected by disturbances.

(Conventional technology) Generally, in a nuclear power plant, from the perspective of ensuring plant safety, the neutron flux in the core is measured and the state of the radiation dose in the core is monitored, and the radiation dose in various parts of the plant, including processes, etc. is measured. In order to monitor the external leakage of radioactive materials, a monitoring device as schematically shown in FIG. 7 is used. That is, this device guides a radiation detection signal from a radiation detector to a signal processing means 1, where it is converted into a voltage signal or a current signal proportional to the radiation dose, and then sent to a subsequent trip determination circuit 2. The trip determination circuit 2 compares the signal level from the signal processing means 1 with a predetermined set value, and outputs a trip signal when the radiation signal level exceeds the set value.

Furthermore, FIG. 8 is a diagram showing a more specific configuration of a conventional radiation monitoring device using an ionization chamber.

In the figure, 3 is a MIM box-shaped radiation La detector, 4 is a coupling capacitor, 5 is a high-voltage power supply for detector bias,
6 is a preamplifier, 7 is a pulse counting circuit, 8 is a counting rate/voltage conversion circuit, and 9 is an analog signal output circuit. That is, this monitor device amplifies a minute current signal of a pulse component generated in response to a radiation aperture detected by an ionization chamber radiation detector 3 using a preamplifier 6, and further amplifies this pulsed current signal using a pulse counting circuit 7. After that, the counting rate/voltage conversion circuit 8 converts the signal into a voltage signal proportional to the radiation dose, and then sends it to the subsequent trip determination circuit 2 and analog signal output circuit 9. This trip judgment circuit 2
compares the voltage signal level with the set value and outputs a trip signal to the outside when the signal level exceeds the set value. On the other hand, the analog signal output circuit 9 converts the signal level into a desired analog signal for use in monitoring by directing or recording the signal level to an indicator or recorder and outputs it. In order to simplify the adjustment and maintenance work, a digital radiation monitoring device using a microcomputer has been developed. In this radiation monitoring device, as shown in FIG. 9, the main CPU card 11 monitors the output of the pulse counting circuit 7 via the system bus 12 and the input/output card 13 at predetermined intervals, that is, the pulse count value corresponding to the radiation dose. After converting it into a voltage signal level proportional to the radiation dose, for example, compares this voltage signal level with a predetermined set value, and based on the comparison result, when the voltage signal level exceeds the set value, the system bus 12 and person output card 1
The monitor function is achieved by outputting a trip signal through 4 and sending the voltage signal to the input/output card 15, where it is converted to an appropriate analog voltage signal or current signal and then sent to an external recorder or indicator. are doing.

Furthermore, this device has additional functions such as a keyboard 16, a CR7 display 17, and a CP for human output/display.
Input/output display function consisting of U card 18, etc., C for external transmission
The PU card 19 is used to transmit signals processed by the main CPU 11 to external devices such as other computers or printers, or the external transmission function provides signals from external devices to the main CPU 1. A diagnostic function for diagnosing health is provided.

(Problem 8 to be solved by the invention) Therefore, as described above, by changing the analog type shown in FIG. 8 to the digital type radiation monitor device shown in FIG. This makes it easy to use, exchange signals with external devices, and perform self-diagnosis, but on the other hand, as various additional functions increase, the number of parts increases significantly, and these parts may deteriorate or be damaged. There is a problem in that the abnormality affects the main function of the main CPU card 11, reducing the reliability of the entire monitor device.

By the way, the radiation monitor device in a nuclear power plant is a trip judgment and recorder.

The main function is to monitor the commanded ejection output, and human output of data via the keyboard 16 and CR7 display 17;
External transmission 1 diagnostic CPU using transmission CPU card 19
Although the diagnostic function provided by the card 20 is an additional function to improve operability and maintainability, microcomputers are generally adopted from the viewpoint of device miniaturization, expandability, and versatility. Rather, it is desirable to provide these additional functions to take advantage of the characteristics of a microcomputer while increasing the reliability of the entire device.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a digital radiation monitor device that can ensure high reliability while making full use of the characteristics of digitalization and providing various added values. .

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention allows the main CPU provided in the system bus t to calculate the radiation dose detected by the radiation detector at a predetermined signal processing time. The radiation dose is compared with a predetermined set value, and when the radiation dose exceeds the set value, a trip signal is output, and after the predetermined signal processing time has elapsed, the corresponding In addition to main function processing means with a standby time shorter than the signal processing period,
An additional function CPU is connected to the upper CPU via the power line of the system bus and an optical bus, and the main CPU
U receives the additional function CP via the destination bus during the standby time.
Additional function processing means is provided which performs signal transmission with the upper CPU and avoids the influence of the main function processing of the upper CPU in the event of an abnormality in the additional function CPU.

In addition, the present invention provides that the additional function CPU includes an input/output display CPU.
U card, external transmission CPU card and diagnostic CP'
The additional function CPU has at least one type of U card, and this additional function CPU is connected to the power line of the system bus by a fuse, and when the additional function CPU has an abnormality, the fuse is blown and disconnected from the system bus, and the additional function CPU is disconnected from the system bus. The upper CPU is configured to perform time-up processing and shift to main function processing when the standby time has elapsed due to an abnormality in the additional function CPU.

(Function) Therefore, by taking the above-mentioned measures, the main function processing means of the present invention includes a main CPU on the system bus, and the main CPU uses the main CPU to detect radiation detected by the radiation detector at a predetermined signal processing time. After capturing the radiation dose, it is converted into an analog signal and outputted, and after the captured radiation dose is converted into a signal level by the ECPU, this signal level is compared with a predetermined setting value, and the signal level is determined. ? , outputs a trip signal when a fixed value is exceeded. On the other hand, after completing the main function processing, the upper CPU executes the additional function processing means. The additional function processing means is configured such that the upper CPU transmits signals with the additional function CPU via the optical bus during the standby time, and when the additional function CPU itself becomes abnormal, it blows the fuse by itself. By disconnecting from the system bus and by performing time-up processing when the additional function processing reaches a predetermined standby time and shifting to the original main function processing, the influence of the additional function on the main function processing can be avoided. , which ensures the reliability of the entire device.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG. Note that in this figure, the same parts as in FIG. 9, that is, the radiation detector 3. Coupling capacitor 4. High voltage power supply 5. Preamplifier 6, pulse counting circuit 7. Main CPU card 11. System bus 12. The main function processing means constituted by the input/output cards 13 to 15, etc. are given the same reference numerals, and detailed explanation thereof will be omitted, and only the additional function processing means 30 will be explained.

This additional function processing means 30 is mainly used for input/output display.
It is composed of a PU card 31, a CPU card 32 for external transmission, a CPU card 33 for diagnosis, etc., and these CPU cards 31 to 33 are mounted on the system bus 12 from the viewpoint of realizing miniaturization of the entire device. bus 1
It is not connected to the signal line No. 2, but is connected exclusively to the power supply line. Therefore, the illustrated arrows ↑ to each card 31 to 33 indicate the power supply line. The main CPU card 11 and other CPU cards 31 to 33 are connected to an optical bus 34.
These CPU cards 11 and 31
33 is configured to send and receive signals by optical transmission. Note that the functional processing of each CPU card 31 to 33 is not particularly different from the conventional one, but in particular, an optical-electrical signal conversion function and an electric-optical signal conversion function are newly provided, and this point is different from that of the main CPU.
The same applies to the card 11. 35 is the keyboard,
36 is a CRT display.

As shown in FIG. 2, each of the CPU cards 31 to 33 is provided with a fuse 37 connected to the power line of the system bus 12 inside.
The fuse 37 is disconnected from the system bus 12 by blowing out the fuse 37 due to a short circuit in the electronic components 32 or 33 or an overcurrent caused by an abnormality in the power supply.

Furthermore, the main CPU card 11 has a multitasking configuration as shown in FIG. In other words, this main CP
The U card 11 has a main task and a transmission task as program units, and after the main task collects radiation detection signals, judges trips, etc., and outputs the necessary signals, it goes into standby. Each CPU card 31 to
Signals are exchanged between 33 and 33. The reason for this program configuration is to prevent signal processing of the main CPU card 11 from being affected by delay or stop of transmission processing due to failure of the CPU cards 31 to 33 other than the main CPU card 11.

Next, the operation of the above device will be explained with reference to FIG. First, the main CPU card 11 collects radiation detection signals at the initial stage of a predetermined signal processing time (step Sl
). Specifically, after taking in the pulse count value obtained by the pulse counting circuit 7 through the system bus 12 and the input/output card 13 at predetermined intervals, the process moves to step S2, where necessary signal processing is performed. . In this signal processing, a counting rate is obtained from the count value of the pulse counting circuit 7, and then converted into a voltage signal level based on this counting rate. Then, this voltage signal level is converted into a desired analog signal by the input/output card 15 and sent to a recorder, an indicator, etc. so that it can be monitored, and the voltage signal level is compared with a set value to set the voltage signal level. When the value exceeds the value, a trip signal is output (step S3).

Here, when the main task program processing by the main CPU card 11 is completed, it becomes a standby state as shown in FIG. 31 to 33 and signal transmission is performed. Note that when this signal transmission time reaches a predetermined standby time, that is, the signal processing cycle time, the process moves to step S5 (1), and an abort process due to a timeout is applied to prevent a delay in the transmission process due to an abnormality in the CPU cards 31 to 33, etc. Alternatively, the signal processing of the main CPU card 11 is prevented from being delayed due to the stoppage.

Therefore, according to the configuration of the embodiment as described above, the main CPU
The card 11 and other CPU cards 31 to 33 perform the above-mentioned signal processing and signal transmission, and at this time, an input/output display CPU card 31, an external transmission CPU card 32, and a diagnostic CPU card perform additional function processing. 33 is in trouble due to a short circuit in its own electronic components, lines, etc., or for various reasons, the CPU card 31, 32゜3
3. Due to overcurrent flowing in the power line to 3, own fuse 3
7 is fused, the abnormal CPU card can be completely disconnected from each system bus 12. the result,
The main CPU card] 1 can execute desired processing using the system bus 12 despite the abnormality of the other CPU cards 31 to 33 and the like. Moreover, each CPU card 31 to 33 is
It is separated from the signal line of the system bus 12, and the main CPU
The main CPU is connected to the card 11 by optical transmission.
The card 11 and each of the additional function CPU cards 31 to 33 can be completely electrically separated, and in this respect, the original main functions of the device are not affected at all. Moreover,
By using a multitasking system for the main CPU II program and performing transmission timeout processing when necessary, it is possible to achieve software isolation between the main CPU card 11 and the other CPU cards 31 to 33. C
The main function program processing by the PU card 11 is performed by another CP.
There is no delay due to stoppage or malfunction of the U cards 31 to 33.

In addition, in the above embodiment, each CPU card 11°31-3
Although a common optical bus 34 is used for the CPUs 3 and 3, for example, as shown in FIG.
The same effects as in the embodiment described above are achieved.

Next, FIG. 6 is a diagram showing another embodiment of the device of the present invention, in which a forced power-off circuit 40 with overcurrent protection for power supply isolation is provided in each CPU card 31 to 33 to prevent overcurrent. In addition to protecting the system power supply and the system bus 12 with the same function as the fuse when the fuse blows, if necessary, the failure indicator 41 indicates that the power of the additional CPU cards 31 to 33 is down, and the main CPU card 11 Based on the abnormality determination, the power of the abnormal CPU card can be forcibly turned off by a command sent via the optical transmission lines 31a to 31d, thereby protecting the entire device. 4
2 is an optical transmission circuit. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, by electrically and software insulating the additional function processing means from the main function processing means, high functionality can be realized through digitalization, and the main function It is possible to provide a digital radiation monitor device in which the processing means is completely protected and can maintain an appropriate monitoring function to increase reliability, and can also have added value by avoiding the influence of additional functions.

[Brief explanation of the drawing]

Figures 1 to 4 are shown to explain one embodiment of the device of the present invention. Figure 1 is a configuration diagram of a digital radiation monitor device, and Figure 12 is a diagram showing the configuration of an additional function CPU card and a system bus. A diagram showing the relationship, Figure 3 is the main CPU in Figure 1
FIG. 4 is a flow chart explaining the operation; FIG. 5 is a configuration diagram showing another embodiment of the device of the present invention; FIG. 6 is a diagram showing the additional function CPU card and the system bus 5 optical bus. Figures 7 through 9 are shown to explain the conventional apparatus. Figure 7 is a block diagram of a conventional general and schematic radiation monitor apparatus, and Figure 8 is a block diagram of a conventional general and schematic radiation monitor apparatus. 9 is a block diagram of a conventional analog radiation monitor, and FIG. 9 is a block diagram of a conventional digital radiation monitor. 3...Radiation detector, 7...Pulse counting circuit, 11
...Main CPU card, 12...System bus, 13
~15...Input/output card, 31...C for input/output display
PU card, 32...CPU card for external transmission, 33
-...Diagnostic CPU card, 34.34a ~ 34d.
... Hikari Bus, 37... Hughes. Only i! idako 4 edict Figure 3 Applicant's agent Patent attorney Takehiko Suzue Figure 4 Figure Figure Figure

Claims (2)

[Claims] (1) In a digital radiation monitor device that monitors the radiation dose at a necessary location in a plant, a main CPU is installed on the system bus, and this main CPU captures the radiation dose at a predetermined signal processing time and converts it into an analog signal. In addition to converting and outputting the radiation dose, the radiation dose is compared with a predetermined set value, and when the radiation dose exceeds the set value, a trip signal is output, and the signal processing is performed after the predetermined signal processing time has elapsed. a main function processing means having a standby time shorter than the main CPU; an additional function CPU is provided to the main CPU via a power line of the system bus and an optical bus;
is the additional function C via the optical bus during the standby time.
1. A digital radiation monitor device comprising additional function processing means that performs signal transmission with a PU and avoids affecting the main function processing of the main CPU when an abnormality occurs in the additional function CPU. (2) The additional function processing means has the additional function CPU consisting of at least one of an input/output display CPU, an external transmission CPU, and a diagnostic CPU, and the additional function CPU is connected to the power source of the system bus. When the additional function CPU is abnormal, the fuse is blown by an overcurrent to disconnect it from the system bus, and the main CPU is connected to the additional function CPU by a fuse.
2. The digital radiation monitor device according to claim 1, wherein when a standby time is reached due to an abnormality in the optical bus, time-up of optical transmission by the optical bus is performed.