JPH0316635B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation monitoring device for monitoring radiation during operation of a nuclear reactor, for example.

As shown in Figure 1, conventional radiation monitoring equipment installs a large number of radiation detectors 2 such as ionization chambers, GM counters, and scintillation detectors in the reactor core and other necessary locations 1, and detects these radiations. The current signal output from the radiation detector 2 is individually introduced into the measurement unit 5 of the radiation monitor panel in the central control room 4 via the signal line 3 from the detector 2. This measurement signal is compared with a preset trip level in a subsequent trip circuit 6, and the comparison result is displayed on a recorder or a contact operation signal is issued to generate an alarm. In the figure, 7 is a high-voltage output line that supplies the high-voltage power output in the measurement unit 5 to the detector 2, 8 is a ground wire, and 9 is a line that displays the measurement signal of the measurement unit 5 or indicates whether or not there is a failure in the detector 2. It is a computer that allows you to do things like

By the way, if we classify the plants based on their importance,
Signals output from a large number of radiation detectors 2 can be classified into two types: signals belonging to the safety system and signals belonging to the non-safety system. No signal processing is performed. For this reason, there is a drawback that installation and maintenance costs are high. In addition, because the radiation detector 2 and the measurement unit 5 are more than 100 meters apart, and because the measurement unit 5 measures minute currents from the radiation detector 2, external noise may enter the signal line 3, resulting in poor measurement accuracy. This has led to a decline in

The present invention was made in order to solve the above-mentioned drawbacks, and provides a radiation monitoring device that reduces the number of signal lines from a radiation detector to a central control room and improves signal reliability. It is something.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 to 4. 2 shows the overall configuration of the apparatus, and FIGS. 3 and 4 are diagrams embodying a part of the measuring unit belonging to the safety system shown in FIG. 2, and detailed functional diagrams of the measuring unit. First, the measurement system belonging to the safety system consists of a radiation detector 11 and a measurement unit 12, which are installed on the site A. This radiation detector 11 has a built-in preamplifier, and measures and amplifies the radioactivity concentration in the reactor core and other installed locations, and outputs the result. The measuring unit 12 mainly includes a digital processing section composed of a microcomputer and a memory, and further includes a built-in high-voltage power supply for the detector. That is, the measurement unit 12 includes, for example, an A-D conversion circuit 121 that digitizes the signal from the detector 11, and a logarithm or rate calculation circuit 122 that converts the digital signal into a logarithm or rate.
A determination circuit 12 compares and determines the output of this circuit 122 with, for example, the trip level of the setting circuit 123.
4, and a DA conversion circuit 125 which converts the signal of the determination result into an analog signal and introduces a recording or trip signal into the recording display section 13.
Furthermore, the measurement unit 12 compares the logarithmic conversion output with, for example, the trip level of the setting circuit 123 in a comparison circuit 126, and sends the digital amount via the output interface 127 to the local station 14 belonging to the non-safety system. In addition, measurement unit 1
2 is a calibration switch 128 and this switch 12.
A calibration signal generator 129 receives the operation signal of 8 and generates a calibration signal, and an A-D conversion circuit 130 converts this calibration signal into an analog signal and sends an analog calibration signal AK to the radiation detector 11. The measurement unit 12 also has an input terminal DI of the unit's local/remote changeover switch SW.
It is equipped with an interface INT for panel display setting P of calculation results and parameters, and an alarm output terminal DO that outputs an alarm signal AR based on the level judgment result.

Next, the non-safety measurement system consists of a radiation detector 21 with a preamplifier and a measurement unit 22, similar to the safety system.
will be installed in The difference between this measuring unit 22 and the measuring unit 12 belonging to the safety system is that there is no output terminal for the recording display signal to the recording display section 13, and its function can be shared or used with some restrictions. It is possible. The outputs of these measurement units 22 . . . are sent to a local station 24 connected to a data bus line 23. 25 is the master station,
26 is a computer.

Therefore, in this device, there are two output systems for signals belonging to the safety system, of which the analog conversion circuit 1
The output line 25 is connected to the record display section 13 in the central control room as in the conventional case, and the output line of the other output interface 127 transmits the calculation results processed by the measurement unit 12 and information on the operating status. It is connected to a non-safety local station 14 via a digital signal line.

On the other hand, the non-safety output interface 22a
has the same function as 127 belonging to the safety system,
It is also connected to the local station 24 via a digital signal line that exchanges the calculation results of the measurement unit 22 and operating status information. These local stations 14 and 24 are connected to a data bus line 23, and a master station 2 controls this data bus line 23.
5, information from the detectors 11 and 21 at the site is transmitted to the host computer 26.

Next, the operation of the device configured as above will be explained. First, radiation detector 2 belonging to the non-safety system
The signal detected at step 1 is amplified by a built-in preamplifier, and digitally processed by a digital processing section of measurement unit 22. In other words, the output of the radiation detector 21 is digitized by an A-D conversion circuit, and the calculated value is compared with the trip level of the setting circuit as a logarithm calculation or rate calculation to determine whether there is a level trip, inoperability, sensor abnormality, etc. It is sent to the local station 24 via the output interface 22a. Then, the master station 25 can manage files by taking in information from each of these detectors 21 at a fixed period or upon receiving an interrupt signal from the measurement unit 22 related to the abnormality detector.
Further, data is exchanged with the computer 26 through a transmission line. Non-safety trip signals do not require as much responsiveness as safety trip signals.
If there are 10 to 20 stations, it is possible to transfer to a higher rank in about 1 second.

On the other hand, the safety system signal processing performs the same data processing as the non-safety system described above, and the local station 1
However, when a trip occurs, the system requirements cannot be satisfied by processing in the same system as in the non-safety system. Therefore, the measurement unit 12 is provided with a signal output section for outputting the trip processing results and the record/display section 13, and the information is sent directly to the central control room. Therefore, with this configuration, the only information required as a safety system function is the calculation time of the on-site measurement units 12 and 22 and the conversion time of the D-A conversion circuit 125, which is not required as a system. response time can be satisfied.

As described above, two systems of signals from the radiation detector 11 belonging to the safety system are provided, and the conventional safety system functions are left as is, while the same processed information is transmitted to the local station 14, which is comprised of a non-safety system group. By installing this system, we aim to unify the signals used as a process radiation monitor.

Note that the present invention is not limited to the above embodiments. The local stations 14, 24, . . . may be of a star type instead of a loop type, and the point is that this may be determined depending on the arrangement of the radiation detectors 11, 21, etc. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

Since the present invention has the above configuration, it has the following effects.

It is possible to reduce the number of cables. By shortening the distance between the measurement unit and the radiation detector and reducing the number of signal lines drawn between the measurement unit and the central control room, both the length and number of cables can be significantly reduced, reducing cable materials and installation costs. This results in savings in costs and maintenance costs.

Can improve noise resistance. Since the measurement unit is installed near the radiation detector, the possibility of being affected by noise between the radiation detector and the measurement unit is reduced, and digitalization between the measurement unit and the central control room reduces the effect of noise. It is possible to provide a radiation monitoring device that has effects such as being able to reduce the amount of radiation used.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional device, FIG. 2 is a schematic configuration diagram showing an embodiment of the radiation monitoring device according to the present invention, and FIG. 3 is a partially embodied diagram of the measurement unit shown in FIG. 2. , FIG. 4 is a detailed functional diagram of the measuring unit. 11, 21... Radiation detector, 12, 22...
Measuring unit, 13...Record display section, 14, 24
...Local station, 13...Master station, 26...Upper computer.

Claims (1)

[Scope of Claims] 1. Performing a comparison judgment and a comparison calculation individually with a logarithm calculation output or a rate calculation output obtained from an output signal of a first radiation detector belonging to a safety system and a predetermined first trip level, The signal resulting from this comparison is converted into an analog signal and sent to the central control room for recording and display as a safety signal, while the digital signal resulting from the comparison calculation is transmitted to the central control room as a non-safety signal. It is possible to compare the logarithm calculation output or rate calculation output obtained from the output signal of the safety system measurement unit installed on the field side and the second radiation detector belonging to the non-safety system with a predetermined second trip level. a non-safety system measurement unit installed on the field side that transmits a digital signal of the comparison calculation result obtained as a non-safety system signal to the central control room; The digital signals sent from the measurement units are individually received at the local station, and the digital signals received at these local stations are sequentially captured at the master station at a predetermined period or based on the interrupt signal from the measurement unit, and then sent to the host computer. transmitted to,
A radiation monitoring device characterized by comprising: means for collectively processing the output states of the respective radiation detectors in the host computer.