JPS63282690A - Run-back control apparatus - Google Patents

Abstract

PURPOSE:To prevent the lowering in the output of a nuclear reactor, by preventing the increase in the speed of a recirculation pump when the operating point of the nuclear reactor reaches a holding line and slowly decreasing the speed of said pump when said operating point reaches a run-back line. CONSTITUTION:When the operating point of the nuclear reactor monitored by a monitor circuit 11 reaches a preset holding line, a holding order is outputted from an interlock circuit 12. Whereupon, an automatic/manual changeover contact 13 is changed over from an a-side to a b-side and a holding contact 15 is turned On and a signal prohibiting speed setting 'increase' operation is applied to a speed controller 4 from a setting device 14. When the operating point of the nuclear reactor reaches a run-back line, a run-back command is outputted from the circuit 12. Whereupon, a run-back contact 17 is turned ON and a gentle speed decreasing command signal is applied to the controller 4 from a run-back signal generator 16. Since the run-back of this recirculation pump gently lowers the speed of the recirculation pump, an operating region generating the deterioration of the capacity of the machinery is evaded and the unnecessary lowering in the output of the nuclear reactor can be prevented.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is a reactor recirculation flow rate control device for a nuclear couplant, which is used to protect equipment such as moisture separator performance maintenance or jet pump cavitation protection. From this perspective, the present invention relates to a runback control device that appropriately reduces reactor recirculation pump speed.

(Prior Art) Conventionally, in a reactor recirculation flow control system of a nuclear couplant, moisture i! In order to maintain reactor performance or protect equipment such as jet pump cavitation protection, if the reactor operating point approaches an operating range where performance deterioration or damage to these equipment may occur, the recirculation pump speed should be reduced to its minimum. An interlock is used to rapidly run back to speed (20% speed) and avoid equipment performance deterioration and 1i scratch generation area.

5 and 6 show an example of a cavitation protection runback interlock in a conventional runback control device 4. As shown in FIG. A cavitation generation line L1 of the jet pump and a runback line L2, which is provided with a slight margin to this cavitation generation line L1, are provided on the jet pump.

On the other hand, the reactor operating point is determined based on the reactor feedwater flow rate signal and the core flow rate signal, and when the reactor operating point reaches the runback line L2, the speed controller circuit as shown in FIG. Turn on runback operation contact 1,
The speed command signal from the upstream controller that has been controlled by the automatic 7-movement switching device 2 is switched to the speed command signal from the runback setting device 3 that has been set in advance, and downstream control is performed via the speed controller 4. Output as a command signal to the section.

As a result, the recirculation pump speed is runback to the lowest speed based on the command signal from the runback setting device 3.

(Problems to be Solved by the Invention) In the conventional runback control device described above, the runback setting speed of the recirculation pump is uniformly set to the lowest 20% speed, so cavitation occurs due to a slight decrease in pump speed. Even if you can avoid the area, you will be reduced to the lowest speed possible.

This causes problems such as an unnecessary reduction in reactor output and a significant reduction in plant availability.

The present invention has been made with these points in mind, and it appropriately avoids the operating range where equipment performance deterioration or damage occurs by reducing the recirculation pump speed to a minimum, thereby reducing unnecessary reactor output. It is an object of the present invention to provide a runback control device that can prevent the runback from decreasing.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a dangerous line for reactor recirculation pump speed that is set from the perspective of equipment protection, a runback line that is set with a slight margin on this dangerous line, and a monitoring unit that monitors the reactor operating point based on the P-F map, each of which has a hold line set with a slight margin to this runback line, and when the reactor operating point reaches the hold line. Speed control includes an interlock circuit that outputs a hold command and a runback command when the runback line is reached, and a speed increase prohibition signal that prohibits the reactor recirculation pump from increasing its speed when the hold command is input. and a speed reduction signal generation section that provides a speed reduction signal to the speed controller to gradually reduce the speed of the reactor recirculation pump in response to input of a runback command. shall be.

(Function) In the runback control device according to the present invention, a danger line, a runback line, and a hold line of the reactor recirculation pump speed are respectively set on the P-F map. Based on this P-F map, the reactor operating point is monitored in the monitoring section.

Here, when the reactor operating point reaches the hold line, a hold command is output from the interlock circuit, and the speed increase prohibition signal generator outputs a speed increase prohibition signal due to the input of this hold command. is applied to the speed controller to prevent the recirculation pump from increasing in speed.

In addition, when the reactor operating point reaches the runback line, a runback command is output from the interlock circuit, and the speed reduction signal generator outputs a speed reduction signal in response to the input of this runback command. is applied to the speed controller, and the speed of the recirculation pump is gradually reduced.

When the reactor operating point returns to the hold line, a hold command is output from the interlock circuit.
A speed increase prohibition signal is output from the speed increase prohibition signal generator to prevent the recirculation pump from increasing in speed.

Further, when the reactor operating point avoids the hold line, the hold command is canceled and normal speed control is performed.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

Figure 1 shows a runback control device for jet pump cavitation protection. In the figure, reference numeral 11 indicates the reactor operating point on the P-F map using the reactor feed water flow rate signal and the core flow rate signal. This is a monitoring circuit for monitoring. As shown in Fig. 2, the P-F map includes the cavitation generation line Ll of the jet pump, a runback line L1 with a slight margin on this cavitation generation line L1, and a slight margin on this runback line L2. A hold line L3 with a margin is set for each, and when it is determined by monitoring in the monitoring circuit 11 that the reactor operating point has reached the hold line L3, an interlock is activated as shown in Figure 1. A hold command is output from the circuit 12, and when it is determined that the reactor operating point has reached the runback line L2, a runback command is output from the interlock circuit 12.

That is, the interlock circuit 12 is equipped with a determination interlock shown in FIG. 3, and when the reactor operating point reaches the hold line L3, a hold command is set, and when the reactor operating point reaches the runback line L2. A runback command is set when the hold line L3 of the reactor operating point is reached, and the hold command is reset by avoiding the hold line L3 of the reactor operating point, and the runback command is reset by setting the hold command.

The hold command output from the interlock circuit 12 that fixes such a configuration is transmitted to the automatic/manual switching contact 13, the setting device 14, and the b side of the automatic/manual switching contact 13 and the setting device, as shown in FIG. 14, respectively, to switch the automatic/manual switching contact 13 from the a side to the b side and to turn on the hold contact 15. As a result, the setting device 14 gives a signal to the speed controller 4 that prohibits the speed setting "increase" operation, inhibits the speed increase command signal to the downstream controller, and locks the recirculation pump speed up. It has become so.

On the other hand, the runback command output from the interlock circuit 12 is transmitted to the automatic/manual switching contact 13 as shown in FIG.
The runback contact 17 between the b side of the
4 respectively provided at tracking contacts 18 between
Both of these contacts 17 and 18 are turned on.

The runback signal generator 16 is equipped with a runback function generator (not shown) having a minute speed reduction function setting as shown in FIG. A speed range command signal from the generator 16 is provided to the speed controller 4 to gradually reduce the recirculation pump speed.

Next, the operation of this embodiment will be explained.

The current reactor operating point is monitored by the monitoring circuit 11 on a P-F map using the reactor feed water flow rate signal and the core flow rate signal. Then, when the reactor operating point reaches a preset hold line L3, a hold command is output from the interlock circuit 12.

The output of this hold command causes the automatic/manual switching contact 1 to
3 switches from the a side to the b side, and the hold contact 1
5 is turned ON, a signal for prohibiting the speed setting "increase" operation is given from the setting device 14 to the speed controller 4, and a speed increase command signal to the downstream controller is prohibited. This locks the recirculation pump speed up and prevents the core flow rate from approaching areas where jet pump cavitation may occur.

By the way, during control rod operation, the reactor operating point moves in the direction of the output shaft in the P-F map 1- shown in FIG. Therefore, the reactor operating point may reach the runback line L2. And in this case, it is necessary to reduce the recirculation pump speed to avoid the jet pump cavitation region.

Therefore, in this embodiment, when the reactor operating point reaches the runback line L2, the determination interlock shown in FIG.
I am trying to output from .

When this runback command is output, the runback contact 17 is turned on as shown in FIG. 1, and a gentle speed reduction command signal is output from the runback signal generator 16 and given to the speed controller 4. This causes the downstream controller to reduce the recirculation pump speed.

Note that since the runback of the recirculation pump has particularly low speed requirements, the recirculation pump speed gradually decreases due to minute changes in the speed range command signal based on the runback signal setting. As a result, the reactor operating point moves in the direction of avoiding the jet pump cavitation area on the P-F map shown in Figure 2, and eventually the hold line L
Return to 3.

When the hold line L3 is returned, the runback command is reset by the judgment interlock shown in Figure 3.
The runback contact 17 is turned OFF, the speed reduction command signal from the runback signal generator 16 is stopped, the runback is canceled, and the speed reduction of the recirculation pump is stopped.

At this time, since the tracking contact 18 is ON, the setting device 14 is tracking the output of the runback signal generator 16, and the recirculation pump speed is kept constant when the runback is released. drooping

Furthermore, if the reactor operating point avoids the hold line L3, the hold command is canceled and the hold contact 15
is turned OFF, and the automatic/manual switching contact 13 is turned OFF.
Thereafter, speed control is performed using a speed command signal from an upstream controller. In other words, normal speed control is restored.

In the above embodiment, a runback control device for protecting jet pump cavitation was explained, but it can also be applied as a runback control device for protecting other equipment such as maintaining the performance of a moisture separator, and similar effects can be achieved. You can expect it.

〔Effect of the invention〕

As explained above, the present invention monitors the reactor operating point with the monitoring unit, and when the reactor operating point reaches the hold line, prevents the speed increase of the recirculation pump, and also prevents the reactor operating point from increasing. When the runback line is reached, the recirculation pump speed is gradually reduced.
Operational regions where equipment performance deterioration or damage occurs can be appropriately avoided by reducing recirculation pump speed to a minimum, and unnecessary reductions in reactor output can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a runback control device showing an embodiment of the present invention, and FIG. 2 is a P-F monitored by the monitoring circuit shown in FIG.
Fig. 3 is an explanatory diagram of the judgment interlock of the interlock circuit of Fig. 1, Fig. 4 is an explanatory diagram of the runback signal setting in the runback signal generator of Fig. 1, and Fig. 5 is an explanatory diagram of the map. An explanatory diagram of a P-F map in a conventional runback control device, FIG. 6 is a configuration diagram showing a conventional runback control device. 4...Speed controller, 11...Monitoring circuit, 12...
Interlock circuit, 14... Setting device, Ll... Cavitation generation line, L2... Run back line, L3... Hold line. Applicant's representative Sato - Male water supply, amount of water at the bottom of the furnace, 1 hour, 1 figure, 2 figures, 3 figures, furnace closing 1, flow rate, 5 figures, frost cooling rate, 6 figures.

Claims (1)

[Claims] 1. A danger line for the speed of the reactor recirculation pump, which is set from the viewpoint of maintaining the performance of the moisture separator or protecting equipment such as jet pump cavitation protection, with some margin provided for this danger line. A monitoring unit that monitors the reactor operating point based on the power-core flow rate curve diagram, which has a runback line set by An interlock circuit that outputs a hold command when the reactor operating point reaches the hold line and a runback command when the reactor operating point reaches the runback line, and an interlock circuit that outputs a runback command when the reactor operating point reaches the runback line. A speed increase prohibition signal generation unit that provides a speed increase prohibition signal to the speed controller that prohibits the speed of the recirculation pump, and a speed decrease signal that gently decreases the speed of the reactor recirculation pump by inputting a runback command. A runback control device, comprising: a speed reduction signal generating section for providing a speed reduction signal to a controller. 2. The runback control device according to claim 1, wherein the speed reduction signal generating section includes a runback function generator having a function setting for minute speed changes.