JPS5838897A - Reactor feedwater control device - 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] Regarding water control equipment.

In general, boiling water f! The JIJJK child power plant uses a direct cycle type in which the cooling water of the i child reactor directly becomes the working fluid of the plant. Therefore, for safe operation, the amount of cooling water used is controlled by the reactor water supply control device because it is necessary to maintain a constant water level in the reactor pressure vessel.

This water supply control device generally consists of a water level detector that detects the reactor water level, a water level setter that sets a predetermined water level, and a proportional, integral, and differential system that controls the water supply amount from the deviation between the detected water level and the set water level. It consists of a controller having elements, and a water supply flow rate drive control mechanism that changes the water supply amount according to the output from this controller.

In such a conventional control device, the control constant of the controller, which is the main part, is constant and is 69. Moreover, in general, 1 is set to allow good control during normal operation.
Reactor water level control under normal conditions is extremely good. However, in boiling water temperature reactors, when there is a sudden change in output, such as a sudden increase or decrease in the recirculation flow rate or a recirculation pump trip, the main steam flow rate changes. As a result, a large imbalance between the main steam flow rate and the feed water flow rate may occur, and the reactor water level may fluctuate significantly due to changes in the void layer in the core. Although it is necessary to quickly stabilize the reactor water level, it has the drawback of being extremely difficult.

Therefore, the present invention improves the above-mentioned conventional drawbacks and performs extremely rapid control of the water supply flow rate when the reactor water level fluctuates significantly. When the amount of deviation from the water level deviates from a predetermined deviation width, the water level deviation signal input to the controller is temporarily expanded via a proportional amplifier to increase the control amount of the water supply flow rate. The aim is to achieve the above objectives.

Hereinafter, with reference to the drawings 1 to 1, an embodiment of the present invention t to g will be described as follows.

The symbol l shown in the figure is the reactor pressure vessel of the rising water type nuclear reactor, and the water level 2 of its cooling water is the water supply mechanism 3.
The main steam flow mA obtained by the steam derivation mechanism 4 is maintained constant by the coupling between the feed water flow rate B supplied by the steam flow rate B and the main steam flow mA obtained by the steam derivation mechanism 4. Also, this water level 2 is due to the recirculation pump 5 attached to the reactor pressure vessel to recirculate the cooling water! In addition, it may fluctuate temporarily depending on the amount of moving parts, and also due to fluctuations in the amount of voids in the core.

Therefore, the water level 2 in the reactor pressure vessel l is determined by water level detection @
6 and output as a reactor water level signal C to an addition/subtraction calculator 7. This addition/subtraction calculator 7 subtracts the reactor water level signal C from the water level setting signal R, which is an output signal from the water level setting @8 that controls the water level 2 in the reactor pressure vessel 1 to a constant level, The deviation between the detected water level and the set water level is output as a water level deviation signal E.

This water level deviation signal E is input to a controller 12 via a comparator 9 equipped with a relay 10, and this controller 12 controls a water supply flow rate drive control mechanism 13 to adjust the amount of water supplied by the water supply mechanism 3. It is supposed to be done.

The comparator 9 compares the water level deviation signal E with the predetermined deviation amount T (deviation between the detected water level and the set water level), and switches the signal route input to the controller 12. It is equipped with lO. When the water level deviation signal E is smaller than a predetermined deviation amount T, this relay 10 sends it to the controller 12, and when it is larger, it is sent to the proportional amplifier 11.
It operates to switch and output the corrected water level deviation signal F to the controller 12 as the corrected water level deviation signal F which has been amplified and corrected.

That is, when the deviation between the detected water level and the set water level exceeds a predetermined deviation amount T, the proportional amplifier 11 amplifies the water level deviation signal E by a predetermined ratio and outputs it as a corrected water level deviation signal F. Something to do.

This becomes the controller input signal G and is input to the controller.

The controller 12 is a proportional, integral, and differential controller that controls the water supply flow rate drive control mechanism 13! ! As described above, the amount of water supplied by the water supply mechanism 3 is determined and adjusted.

Next, the power fluctuates rapidly, and the water level in the reactor pressure vessel 2
The effect when the value changes to large I will be explained based on FIG. 2.

When output fluctuation occurs and the main steam flow rate A begins to change.

Since the effect of the change in the void layer in the reactor and the feed water flow rate B do not follow instantaneously, an imbalance occurs during that time, and as a result, the reactor water level signal C begins to change. At this time, since the water level setting is constant, the water level deviation signal E output from the addition/subtraction calculator 7 in response to the deviation between the detected water level and the set water level changes in the same way as the reactor water level signal C changes. start. For a while after the change starts, the water level deviation signal E is smaller than the preset deviation amount T, so it becomes the 11 controller input signal G to control the water supply flow rate B.

During normal small output fluctuations, the water supply flow rate B is controlled by such sequence control, and the water level 2 is controlled to return to the set water level.

On the other hand, if a large and sudden change in output occurs,
The water supply flow rate B cannot be controlled sufficiently.

The water level deviation signal E becomes larger than the preset deviation amount T after a while. At that point, the relay lO of the comparator 9 is switched, and the water level deviation signal E is switched to the corrected water level deviation signal F which has been amplified and corrected by the proportional amplifier 11. This corrected water level deviation signal F is the water level deviation signal E
Since the signal is amplified at a predetermined ratio, a sudden and large output signal is input to the controller ν, and as a result, the feed water flow rate B is suddenly changed, causing fluctuations in the water level 2 in the reactor pressure vessel 1. This is a major control that quickly suppresses the Then, by the operation 1 or more, the fluctuation of the water level 2 is suppressed and the water level returns to the set water level 9. When the water level deviation signal E returns to the number ζ within the range of the predetermined deviation amount T, the controller input signal G again changes to the water level. After switching to the deviation signal E, the water level 2 is thereafter controlled at a relatively gentle rate until the water level returns to the set water level.

Therefore, even if the control constants of the controller 12 are suitable for normal operation, even if the water level in the reactor pressure vessel l fluctuates greatly, the amplified and corrected control input signal G will respond to the feedwater flow rate. The drive control mechanism 13 can be greatly controlled.
Since the power generation plant is configured to operate in a stable manner, it is possible to perform sufficiently rapid and stable operation control, which has the advantage that it is possible to improve the operating rate of one power generation plant.

That is, when the deviation between the detected water level and the set water level exceeds a predetermined deviation amount T, the water level deviation signal E input to the controller that controls the water supply flow rate drive control mechanism 13 is expanded. This is because the proportional amplifier 11 that uses the corrected water level deviation signal G is inserted, and since the proportional amplifier 11 can be easily incorporated into the conventional water supply control device, it can be installed without major modification of the conventional device. It's convenient.

As explained above, according to the present invention, only when the water level deviation becomes larger than a certain amount, the deviation signal obtained from the deviation signal is amplified and inputted to the controller by providing a control eccentricity. Our goal is to provide a reactor water supply control system with extremely high control capabilities and plant availability.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and figure #I1 is a block diagram, and figure g2#A is a line diagram showing its operation. l...Reactor pressure vessel, 2...Water level, 3...Water supply mechanism. 4... Steam derivation mechanism, 5... Recirculation pump, 6...
・Water level detector, 7... Addition/subtraction calculator, 8... Water level setter, 10... Relay, 9... Comparator, 11... Proportional amplifier, 12... Controller, 13. ...Water supply flow rate drive control mechanism, A...Main steam flow rate, B...Water supply flow rate, C
...Reactor water level signal, D...Water level setting signal, E...
・Water level deviation signal, G...controller input signal, T...deviation amount. 545

Claims (1)

[Claims] 1. A water level detector that detects the reactor water level in the reactor pressure vessel, a water level setting device that sets the reactor water level at Wr constant, and the deviation between the detected water level and the set water level as water level deviation. An addition/subtraction calculator that outputs as a signal, and a controller that has proportional, integral, and differential elements that control the water supply flow rate drive control mechanism based on the input water level deviation signal, compare the magnitude of the deviation, and compare the magnitude of the deviation and Nine ratio I2 equipped with a relay to switch the signal route.
In the reactor water supply control system, which consists of a
A nuclear reactor water supply control system, characterized in that a proportional amplifier is installed for amplifying a water level deviation signal input to the controller and outputting the expanded water level deviation signal as a corrected water level deviation signal. 2 The relay of the comparator operates so that when the water level deviation signal is smaller than a predetermined deviation amount, it is sent to the controller as is, and when it is larger, it is switched and output to the controller as a corrected water level deviation signal that has been amplified and corrected by the proportional amplifier. A nuclear reactor feed water control device according to claim 1.