JPS5975186A - Automatic control device for reactor power - 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 device suitable for preventing nuclear power output fluctuations due to rapid fluctuations in neutron detection signals due to abnormalities in neutron detectors. .

[Prior art]

In light water boiling reactors, reactor output control is performed by adjusting the position of the control rods in the reactor core and by adjusting the flow rate of the recirculation system that forcibly circulates coolant to the reactor, and in light water pressurized reactors, This is done by adjusting the control rod position in the reactor core and adjusting the boron concentration in the reactor coolant.In heavy water-moderated light water boiling reactors, the control rod position in the reactor core is adjusted and the boron concentration in heavy water is adjusted. It is carried out by Such power control of a nuclear reactor is performed by grasping the power output of a nuclear reactor by utilizing characteristics unique to a nuclear reactor, such as calculation of a local power factor of a nuclear reactor and calculation of a void reactivity coefficient.

These calculations of local output factors, void reactivity coefficients, etc. are usually performed by detecting the number of neutrons using a plurality of neutron detectors. In particular, in light water boiling reactors or heavy water moderation reactors, multiple neutron detectors are placed in the reactor core to improve measurement accuracy, and the detection signals of each neutron detector are averaged to calculate the reactor output. I am using it as a monitor.

In order to improve reliability, the automatic reactor output control system that monitors the reactor output described above averages the detection signals of the neutron detectors in two systems independently to understand the operating status of the reactor. ing. An example of such an automatic reactor power control device is shown in FIG.

In the reactor (not shown) in FIG. 1, for example, 10At + 10A2 + 10A constituting the A system
1 and l0B1.10B2 +... which constitutes the B system.
...10B, is the arrangement. These neutron detectors 1
0AI, 10A2 +...10Au, 1
The detection signals of 0Bt +10Bt, . . . 10B are amplified by amplifiers 12A and 12B and then input to averaging circuits 14A and 14B, which are processing devices. The averaging circuits 14A and 14B average the input detection signals, and send the averaged signals to the high value priority circuit (HV) via the input buffer 16.
G) Send output signal to 18. The high value priority circuit 18 sends the large output signals of the averaging circuits 14A and 14B. The control rod drive control circuit 20 then drives a control rod drive device 24 via an A/M station (automatic/manual switch) 22 to insert a control rod (not shown) into the reactor core.

In the automatic reactor output control system configured as described above, for example, one of the neutron detectors in the A system may fail, and the detection signal of this failed neutron detector outputs a value smaller than the output signal that should actually be output. In this case, high value priority circuit 18
If it does not operate, it will not lead to fluctuations in the reactor output.

In such a case, when the reactor output increases more than necessary, the output value of the average circuit 14B of the B system increases, and the high value priority circuit 18 operates to automatically insert the control rods. . However, due to a failure in one of the neutron detectors in system A, the output signal of the average circuit 14A of system A becomes higher than the output state of the reactor, even though the output of the reactor is normal. The high value priority circuit 18 is activated, automatically inserting control rods into the reactor, and varying the reactor output.

[Purpose of the invention]

The present invention was made in order to eliminate the drawbacks of the prior art, and an object of the present invention is to provide an automatic reactor power control device that can prevent fluctuations in reactor power due to failure of a neutron detector. shall be.

[Summary of the invention]

The present invention calculates the difference between the output signals of a plurality of devices that process the detection signals of the neutron detector in parallel with the high-value priority circuit, and if this difference is equal to or greater than a preset value, it is determined that the neutron detector is malfunctioning. The control rod drive system was switched to manual mode, and the high value priority circuit prevented the control rods from being automatically inserted into the reactor core even if a control rod insertion command was given, thereby preventing fluctuations in the reactor's output. It is something.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the automatic reactor power control system according to the present invention will be described in detail with reference to the accompanying drawings. Similarly, the same reference numerals are given to the parts corresponding to the parts explained in the above-mentioned prior art, and the explanation thereof will be omitted.

FIG. 2 is an explanatory diagram of an embodiment of the automatic reactor power control device according to the present invention. In Fig. 2, the average circuit 14 of system A
The output signals from the averaging circuits 14B of the A and B systems are input to the comparator 26 connected to these averaging circuits 14A and 14B, and are also input to the high value priority circuit 18 via the input buffer 16 as in the conventional case. be done. Comparator 26 is connected to A/M station 22 and provides a signal to A/M station 22 to switch control rod drive 24 from automatic operation to manual operation.

The operation of the embodiment configured as described above is as follows.

When the comparator 26 receives the output signal of the A-system averaging circuit 14A and the output signal of the B-system averaging circuit 614B, it compares both output signals. This comparator 26 has an average circuit 14A.
, 14B exceeds the error range, a signal for switching the A/M station 22 to the manual mode is given to the A/M station 22.

That is, when the difference between the output signal of the averaging circuit 14A and the output signal of the averaging circuit 14B exceeds a predetermined value that is appropriate for considering that the difference is due to a failure of one of the neutron detectors, Switch the A/M station 22 to manual mode. For this reason, for example, a failure occurs in one of the neutron detectors of system A, and the output signal of the average circuit 14A of system A is transmitted to the average circuit 1 of system B.
4B output circuit, A/M station 22 is manually switched by the signal from comparator 26.

Therefore, the output signal of the averaging circuit 14A is
6 to the high value priority circuit 18 and gives a control rod insertion signal to the control rod drive control circuit 20, the signal from the control rod drive control circuit 20 is cut off at the A/M station 22, and the control rods are not inserted. It is not automatically inserted into the core and is held in its current state. Therefore, fluctuations in the output of the nuclear reactor due to failure of the neutron detector can be prevented, and the reliability of the nuclear reactor can be improved.

FIG. 3 shows another embodiment of the automatic reactor power control system according to the present invention.

The automatic reactor power control system shown in Fig. 3 consists of a neutron detector 10Ate 10A2 + 10BII 10B2
is input to the A-system averaging circuit 14A and the B-system averaging circuit 14B. This is because the absolute number of neutron detectors is small, and the neutron detectors that input the output signal to the averaging circuit 14A and the neutron detectors that input the detection signal to the averaging circuit 14B are separated, so that the average reactor output can be accurately adjusted. Since it is insufficient for good monitoring, the neutron detector is shared between the A system and the B system. In such a device, if any one of the neutron detectors fails, the detection signal of that neutron detector is input to both the averaging circuits 14A and 14B.
The detection signals of 4A and 14B similarly fluctuate.

Therefore, in this embodiment, the output signal of the averaging circuit 14A is inputted to the comparator 26 via the rate of change limiter 30 provided in the comparator 28. This rate of change limiter 3
0 means that when the input signal fluctuates, the rate of change limiter 3
This is so that the signal output by 0 always increases or decreases at a rate of change that is less than the one-step value. For this reason, the neutron detector 10A
I.

10 Aa + 1081r 10 When a failure occurs in any one of B2, among the signals input to the comparator 26, the signal from the average circuit 14B is input to the average circuit 14A via the rate of change limiter 30. The rate of change is greater than that of the output signal of , and a difference occurs between the two. Therefore, when the difference exceeds a predetermined value, the comparator 26 switches the A/M station 22 to the manual mode.

In the above embodiment, a case has been described in which the output signal of the averaging circuit 14A is inputted to the comparator 26 via the rate of change limiter 30. A so-called delay element circuit that outputs the signal while holding it to zero may be used.

〔Effect of the invention〕

(9) As explained above, according to the present invention, failure of the neutron detector is detected from the difference between the output signals of a plurality of averaging circuits, and the failure of the neutron detector is detected by manually switching the control rod drive device. It is possible to prevent fluctuations in reactor output based on

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a conventional automatic reactor power control system;
FIG. 3 is an explanatory diagram of an embodiment of the automatic reactor power control device according to the present invention, and FIG. 3 is an explanatory diagram of another embodiment of the automatic reactor power control device according to the present invention. 10Atr 1OA2110Am, 10Bt. 10B2.1OB,...neutron detector, 14A. 14B...Average circuit, 18...High value priority circuit, 20
...Control rod drive control circuit, 22...A/M station, 24...Control rod drive device, 26...Comparator,
28...ratio (10)

Claims (1)

[Claims] 1. A plurality of neutron detectors that detect the operating state of a nuclear reactor, a plurality of processing devices that independently process the detection signals of the plurality of neutron detectors, and a plurality of processing devices that In an automatic reactor output control system having a high value priority circuit that operates a control rod drive device via a control device when any one of the output signals is equal to or higher than a preset value, A comparison device is provided which calculates the difference between the output signals of each of the processing devices and outputs a signal for switching the control rod drive device to manual operation when this difference is equal to or greater than a preset value. Automatic reactor output control device. 2. The comparison device has a rate of change limiter or a delay element circuit, and at least one of the output signals of each of the processing devices is inputted via the rate of change limiter or delay element circuit. An automatic reactor power control device according to claim 1.