JPS59116086A - Automatic power control device for reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an automatic reactor power control system that measures neutron flux and automatically controls the reactor output, and in particular, relates to a method for automatically controlling the reactor output by measuring neutron flux, and in particular, to a method for automatically controlling the reactor output by measuring neutron flux. The present invention relates to an automatic reactor power control device suitable for preventing fluctuations in reactor power due to a single failure.

[Prior art]

Nuclear reactor output control is performed by utilizing the unique characteristics of a nuclear reactor. In light water boiling reactors, the control rod position within the reactor core is adjusted and the flow rate of the recirculation system that forcibly circulates coolant to the reactor is adjusted. This is done by adjusting the concentration of riboron in the reactor coolant, and in heavy water-moderated light water boiling reactors, by adjusting the position of control rods in the reactor core and adjusting the boron concentration in heavy water.

In order to automatically perform the above-mentioned reactor power control, a means for measuring the reactor power is required, and a plurality of neutron detectors are usually used. In order to improve measurement accuracy, neutron detectors are placed inside the reactor core in light water boiling m reactors or heavy water moderation reactors, and are used to monitor reactor output by averaging the signals of multiple neutron detectors. It is said that

FIG. 1 shows a typical configuration example when the above reactor output monitor is used in an automatic reactor output control system.

Output signals from a plurality of neutron detectors 1 and neutron amplifiers 2 installed in the reactor are input to an averaging circuit 3 and averaged to measure the reactor output. The reason why two output monitors, A system and B system, are installed independently is to improve the reliability of the reactor output monitor. The output of the averaging circuit is input to the input buffer 4,
The entire high value priority circuit 5 is inputted to the control rod drive control circuit 6.

In the automatic reactor power control system described above, if a single neutron detector fails and the signal fluctuates to the low side, the high value priority circuit 5 prevents the signal from fluctuating to the multiple reactor power fluctuation.
If the power fluctuates to the high side, control rods are automatically inserted to vary the reactor output.

[Purpose of the invention]

The present invention relates to an automatic reactor power control system that controls multiple reactor power by monitoring the reactor power with a neutron flux detector, and the purpose of the present invention is to prevent changes in the neutron flux signal due to a single failure of the neutron flux detector. The object of the present invention is to provide a means to detect and switch reactor output control from automatic to manual, thereby preventing fluctuations in reactor output.

[Summary of the invention] In the case of a single failure of a neutron flux detector following fluctuations in the reactor output, only the output signal from the relevant detector shows a high level, so comparison with the output signals of other normal detectors is required. If monitoring is performed, it is possible to detect failures. Especially in heavy water reactors, etc., where the neutron movement area is large compared to the reactor core, detection signals of adjacent detectors whose detection signals normally change following each other can be detected. Based on the idea that detection can be achieved reliably by performing comparative monitoring between , which detects detector failures and prevents fluctuations in reactor output.

[Embodiments of the invention]

An embodiment of the present invention will be explained below with reference to FIG. Neutron flux detectors that compare changes in neutron flux signals are selected in such a way that comparisons are made between detectors whose detection signals show similar changes to the extent possible, and detection signals due to neutron flux detector failures are selected. kg is distinguished from the change in the detection signal due to a true change in reactor output that is not due to a failure. Figure 2 shows a case where VC1 is compared and monitored for each of two adjacent neutron flux detectors.
2. The deviation calculation circuits 13, 14 and calculation circuits 15 and 16 are installed in exactly the same way, and the comparison circuit compares the rate of change of the neutron flux signal between the two selected detectors.

Abnormally high signal X due to a single failure of one neutron flux detector 1
' is output, this abnormally high signal becomes the signal X just before the failure, which is output for the delay time period via the first-order delay circuit 11.
The deviation (change width) (X'-x) from the above is calculated by the deviation calculation circuit 13. If this change occurs, the A/M in the reactor power control device
Issue command to station 7 and start automatic control #Jwari@1
Switch to

〔Effect of the invention〕

According to the invention, by monitoring a single failure of a neutron detector,
Fluctuations in the reactor output due to this can be prevented, and this can greatly contribute to stabilizing reactor output control and improving reliability.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional automatic reactor output control circuit;
The figure is a configuration diagram of a circuit provided for each of the two selected neutron detectors for comparing the variation range of neutron signals.

Claims (1)

[Claims] 1. In the reactor automatic output control system, which consists of a neutron flux detector, a signal processing circuit, and a reactor output control system, the change width 'ft of the output signal of each neutron detector is monitored, and this is compared between each detector. 1. A nuclear reactor automatic output control device characterized by being provided with a neutron flux signal comparison and monitoring circuit.