JP2848660B2 - Output range monitor of digital nuclear instrumentation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] [Field of Industrial Application] The present invention relates to an output range monitor of a nuclear instrumentation system in a nuclear power plant or the like.

[Conventional technology]

Generally, in a nuclear power plant or the like that requires high safety, an output area monitor is provided in a nuclear reactor instrumentation system. Conventionally, such devices have been mostly of the analog type, but digitization has recently been considered.

FIG. 2 is a diagram showing a configuration example of a digitized output area monitor.

This output area monitor is configured such that a predetermined number of detection signals of a plurality of neutron detectors 2 installed in the reactor 1 are transmitted via a metal cable 3 to a local output area monitor (hereinafter, “LPRM”)
4). Similarly, a detection signal from the neutron detector 2 connected to each of the other plurality of LPRMs is also input. Further, a flow signal obtained by measuring the flow rate at the inlet of the recirculation pump 5 of the nuclear reactor 1 with the flow meter 6 and converting the measured value into an electric signal by the flow rate transmitter 7 is input to each LPRM 4. The input neutron detection signal and flow rate signal are converted into digital signals, and the average output area monitor (hereinafter, referred to as “APRM”) is transmitted via an optical fiber cable.
8 is output. The APRM8 calculates the percent output of each neutron detection signal, calculates the average output from all percent conversion values, determines the set level based on the flow rate signal, and outputs a scrum signal when the average output exceeds the set level. I do. On the other hand, the percentage conversion value and the average output, which are the calculation results in the APRM 8, together with the flow rate signal, are used to prevent the control rod withdrawal (hereinafter referred to as "RBM") 9
Transmitted to The RBM9 performs a predetermined calculation process using the percent conversion value, compares the calculation result with the set value determined by the flow signal, and outputs a control rod withdrawal prevention signal when safety may be impaired. Output to reactor operation system.

By the way, since the conventional LPRM4 is composed of only hardware, the percent conversion operation of the neutron detection signal is performed by the APRM8. In addition, the flow transmitter 7
In order to transmit the flow rate signal output from to the APRM8 using the optical fiber cable connecting LPRM4 and APRM8,
The flow signal was once input to LPRM4. However, in the APRM8, since the determination regarding the output of the scrum signal is given priority, a considerable delay occurs before the percent conversion operation is performed. In addition, since the detection system of the neutron detection signal and the detection system of the flow signal are integrated, there is a possibility that the reliability of the signal is reduced. In addition, for example, the APR is
The flow rate signal is not transmitted to the M8, and there is an inconvenience that the whole monitored by the APRM 8 is affected.

[Problems to be solved by the invention]

Therefore, with conventional monitors, the response time from when the neutron detector detects the state inside the reactor to when the RBM operates based on the detected data may depend on the processing time of the APRM, and the response time may be slow. was there. Further, since the detection system of the neutron detection signal and the detection system of the flow signal are integrated, there is a problem that the reliability of the signal is lowered.

The present invention has been made in view of the above circumstances,
To provide an output range monitor of a nuclear instrumentation system that can greatly shorten the response time until a control rod pull-out prevention signal is output, improve safety, and improve data reliability. The purpose is to:

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a local output area monitor to which detection signals of a plurality of neutron detectors installed in a nuclear reactor are inputted, The average output of the reactor is calculated based on the output from the local output area monitor, and when the calculated average output exceeds the set level determined by the flow signal detected from the recirculation flow of the reactor, the scram A digital nuclear reactor instrumentation system comprising: an average output area monitor for outputting a signal; and a control rod withdrawal inhibition monitor for outputting a control rod withdrawal inhibition signal based on the outputs of the local output area monitor and the average output area monitor. In the output area monitor, a calculation function relating to local output is added to the local output area monitor, and the calculation result regarding local output in While directly input to the average power range monitor and the control rod withdrawal blocking monitor, and configured to directly input the flow rate signal to the average power range monitor.

[Action]

According to the present invention, by taking the above measures, the local output area monitor performs an operation relating to the local output, and the operation result is directly input to the average output area monitor and the control rod withdrawal prevention monitor. Then, an averaging operation is performed based on the input signal to determine the output of the scrum signal, and the operation result is output to the control rod pull-out prevention monitor. In the control rod pull-out prevention monitor, the output of the control rod pull-out prevention signal is determined based on the calculation result directly transmitted from the local output monitor and the signal processed before the scrum determination in the average output area monitor. Therefore, the control rod withdrawal prevention signal can be determined without waiting for the scrum signal output determination, and the response speed can be greatly improved.

In addition, by adopting the above means, the flow rate signal that detects the recirculation flow rate of the reactor is directly input to the average power range monitor, where it is used to determine the set level when determining the output of the scram signal. Therefore, the flow rate signal can be reliably transmitted to the average output area monitor without being affected by the local output area monitor, and the reliability of the data and the reliability as the monitor are improved.

〔Example〕

Hereinafter, examples of the present invention will be described. FIG. 1 is a diagram showing a configuration of an output area monitor according to one embodiment of the present invention. The same parts as those of the monitor shown in FIG. 2 are denoted by the same reference numerals. In the present embodiment, a plurality of LPRMs 11 are respectively connected to a predetermined number of neutron detectors 2 installed in the reactor 1, and each LPRM 11 converts a detection signal of the neutron detector 2 into an A / D signal.
A / D converter to convert and A / D as operation related to local output
A calculating unit that converts the percentage of each detection signal converted into a digital signal by the conversion unit and monitors the signal level of each detection signal based on the percentage output conversion value; and a transmission that outputs a calculation result of the calculating unit. And a part. Each LPRM 11 is connected to A via optical fiber cables 12 and 13.
It is connected to PRM14 and RBM15 respectively.

The APRM 14 is connected to a predetermined number of the plurality of LPRMs 11 and a flow transmitter 16. APRM14 is
The flow rate signal from the flow rate transmitter 16 is converted into a digital signal, and a set value for scrum determination according to the flow rate value is set.
The reactor power is calculated by averaging the percent power conversion value transmitted from the LPRM 11, and a scram signal is output to the reactor emergency shutdown system when the reactor power exceeds a set value. Further, the ARPM 14 outputs an average output signal and a flow rate signal required for the gain configuration of the RBM 15 to the RBM 15 via an optical fiber cable.

The RBM15 sets the set value for the output determination of the control rod withdrawal prevention signal based on the flow signal from the APRM14, and performs the average calculation of the percent output conversion value calculated by the LPRM11.
The RBM level is obtained, and when the RBM level exceeds the set value, a control rod withdrawal prevention signal is output to the reactor operation system.

Next, the operation of the present embodiment configured as described above will be described.

Each LPRM 11 takes in the detection signal of the neutron detector 2 connected thereto, performs A / D conversion, and executes an operation related to conversion of the percentage output of each detection signal. The percentage output converted value that is the calculation result is the optical fiber cable 1.
It is transmitted to APRM14 and RBM15 via 2,13. On the other hand, A
The flow rate signal from the flow rate transmitter 16 is directly input to the PRM 14. The flow rate signal input to the APRM 14 is digitally converted, used as data for percent conversion and scrum determination, and output to the RBM 15. APRM14
Calculates the reactor output by averaging the percent conversion values, compares the reactor output with the set value, and outputs a scram signal to the reactor emergency shutdown system when the reactor output exceeds the set value. You. In the RBM15, the percent output conversion value is directly transmitted from the LPRM11, and the APRM14
The average output signal and the flow rate signal obtained before the scrum determination are input. Then, an average calculation of the percent output converted value is executed to determine the RBM level, and the RBM level is compared with the set value determined by the flow signal, and the RBM level is calculated.
When the level exceeds the set value, a control rod withdrawal prevention signal is output to the reactor operation system.

Therefore, in the present embodiment, the operation related to the control rod pull-out monitoring performed by the RBM 15 is a percentage output converted value directly transmitted from the LPRM 11, and is obtained by the operation before the scrum determination in the APRM 14, and is directly transmitted to the RBM 15. The flow is performed using the flow signal, and the time required from the time when the neutron detector 2 detects the state in the reactor to the time when the control rod withdrawal prevention signal is output by the RBM 15 is caused by waiting for the scram determination by the APRM 14. The delay is not included, and an extremely fast response speed can be realized.

In addition, since a flow signal for determining a set value serving as a reference for scram determination in the APRM 14 is directly input to the APRM 14 from the flow transmitter 16, the detection system for the neutron detection signal and the detection system for the flow signal are separated, and the flow rate is determined. Signal is LPRM11
Can be reliably prevented from being affected by the data, and data reliability can be improved.

[Effects of the Invention] As described in detail above, according to the present invention, the response time until the control rod withdrawal prevention signal is output can be significantly reduced,
It is possible to provide a power range monitor of a digital nuclear reactor instrumentation system capable of improving safety and improving data reliability.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an output area monitor according to an embodiment of the present invention, and FIG. 2 is a configuration diagram of a conventional output area monitor. 1 ... Reactor, 2 ... Neutron detector, 3 ... Metal cable, 5 ... Recirculation pump, 6 ... Flow meter, 11 ... LPR
M, 12,13 …… Optical fiber cable, 14… APRM, 15…
… RBM, 16 …… Flow transmitter.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G21C 17/10 G21C 17/00 G21D 3/04

Claims (1)

(57) [Claims] 1. A local output area monitor to which detection signals of a plurality of neutron detectors installed in a reactor are input, and an average output of the reactor is calculated based on an output from the local output area monitor. An average output area monitor that outputs a scram signal when an average output as a calculation result exceeds a set value determined by a flow signal that detects the recirculation flow rate of the reactor; the local output area monitor and the average output area In a power range monitor of a digital reactor instrumentation system having a control rod withdrawal prevention monitor for outputting a control rod withdrawal prevention signal based on a monitor output, an arithmetic function relating to a local output is added to the local output region monitor. The operation result of the local output in the local output area monitor is directly input to the average output area monitor and the control rod withdrawal prevention monitor, An output range monitor for a digital reactor instrumentation system, wherein the flow rate signal is directly input to the average output range monitor.