JPS60192298A - Recirculating flow controller for nuclear 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 interface for forcibly recirculating reactor water using a plurality of pumps installed at the bottom of a gap between a core shroud and a pressure vessel wall in a nuclear reactor. Regarding the control device for the internal pump of a null pump nuclear reactor, in particular, rather than installing a controller and pump drive device for each of multiple internal pumps, Divide into several groups, and one for each group.
In addition to installing one controller and pump drive device, we have also developed a control system that allows the pump to be started and stopped by isolating it from other pumps even if a problem occurs in one pump while multiple internal pumps are in operation. The present invention relates to a nuclear reactor recirculation flow control device equipped with a nuclear reactor recirculation flow rate control device.

[Background of the invention]

In FIGS. 1 and 2, which schematically show the reactor vessel, the reactor core shroud 200 is connected to the reactor pressure vessel wall 1.
It is stored in 00. A plurality of internal pumps 12 are provided at the bottom of the gap between the pressure vessel wall 100 and the core shract 200. Each internal pump 12 is rotationally controlled by a motor 12A. Figure 2 is 1
Arrangement of two internal pumps 12 (P, ~P1□)!
Give an example. Each internal pump 12 is arranged at equal intervals. These pumps are designed to have sufficient output so that even if one of the pumps fails and has to be stopped, the other 11 pumps can provide a sufficient recirculation flow rate.

The above-mentioned internal pump reactor recirculation system usually has 1
The current internal pump nuclear reactor recirculation flow control system has 0 to 12 pumps, but each internal pump has an automatic manual control switch, lower controller, signal limiter, Each of the control devices includes one set of control devices such as pump drive devices, resulting in a large-scale control device configuration. For this reason, attempting to manually operate these control devices individually would place a very heavy burden on the operator, and if the control devices were to be placed in the central control room, this would also pose a major problem in terms of space.

On the other hand, the conventional external loop control system for the reactor recirculation system, which has two pumps, has a simple control system configuration because it has two pumps, and its scale is also similar to that of the internal pump type. It was 115 to 1/6 compared to the case, and the operation was easy.

Therefore, in an attempt to make the internal pump type nuclear reactor recirculation flow rate control device the scale of an external loop platter, we decided to
The internal pumps are divided into several groups, and this one
Simply one set of automatic manual control switch for each group,
Installing a lower-level controller, signal limiter, and pump drive device makes it impossible to start and stop each pump individually, so if a problem occurs with one pump, this pump can be disconnected from the others and the remaining pumps can be used to restore the rated power. The greatest advantage of the internal pump reactor recirculation system, which is the ability to continue power operation, will be lost.

[Purpose of the invention]

The purpose of the present invention is to reduce the control device configuration to the same scale as a conventional external loop type recirculation flow control device, and at the same time, provide an internal pump type recirculation system that can continue to operate at the rated output even if one pump is malfunctioning. It is an object of the present invention to provide an internal pump type nuclear reactor recirculation flow rate control device having a control method that allows one pump to be started and stopped by separating it from other pumps without losing the greatest advantage of the present invention.

[Summary of the invention]

The present invention divides a plurality of internal pumps into several groups, installs one set of lower control devices for each group, and provides one set of control devices exclusively for starting and stopping for all pumps. It is characterized by

Figure 3 shows the current internal pump type nuclear reactor recirculation flow control system with 12 pumps.

FIG. 4 shows a conventional external loop reactor recirculation flow rate control device. Comparing these two types of control device configurations, the internal pump type is about six times as large as the conventional type, and it would be extremely burdensome for the operator to operate each one manually. growing. Also, even if each control calculation unit is a separate control device, the main controller 2. Main automatic manual control switch 3. The lower automatic manual control switch 7 and the like must be placed on a central monitoring control panel that is easy for operators to operate, which also poses a problem in terms of panel space.

Therefore, in order to solve these problems, the internal pumps are divided into several groups, and each group has an automatic manual control switch 7. Lower controller 8° signal limiter 9. By installing a group of lower control devices such as the internal pump motor drive device 10, it is possible to achieve a control device configuration of the same size as a conventional external loop type recirculation flow rate control device. Figure 5 shows the configuration of an internal pump type reactor recirculation flow control system in which 12 pumps are divided into two groups of six pumps, and a conventional external loop type reactor recirculation flow rate control system that has two pumps. Here is an example of a simple application of .

However, if the external loop type control device configuration is simply applied to the internal pump type as shown in FIG. 5, the scale will be almost the same, but it will be impossible to start and stop each internal pump.

This means that the biggest advantage of the internal pump type recirculation system, which is that even if one pump breaks down and becomes inoperable, the remaining pumps can continue operating at their rated output is lost.

As a countermeasure for this, the internal pump motor drive device 1
breaker 1 installed between 0 and internal pump 12
Alternatively, a method of starting and stopping each pump may be considered, but this method also has the following drawbacks. In other words, the pumps other than the failed one continue to operate at their rated capacity, but if only the failed pump is disconnected using a circuit breaker, the pump rotation speed suddenly drops to zero, and the remaining pumps compensate for the reduced core flow rate. Therefore, the rotation speed increases rapidly. This causes a disturbance to the core flow rate and is also inconvenient in investigating the cause of the failure because it is impossible to stop the pump while gradually reducing the pump flow rate.

Furthermore, even when a pump recovers from a fault and is put into operation, the other pumps are operating at their rated values, so when the circuit breaker is turned on, the pump rotational speed will suddenly rise from zero to the rated value, and once it reaches the rated value. Draws a trajectory that stabilizes after overshooting. This sudden increase in pump rotational speed causes the reactor core flow rate to increase and the neutron flux to rise rapidly, leading to the generation of a high neutron flux alarm and possibly even a high neutron flux scram. Such a situation is not desirable from the standpoint of nuclear reactor operation, and from the standpoint of ensuring the integrity of the fuel, the phenomenon of a sudden increase in pump rotational speed must be avoided at all costs.

Therefore, if this problem of disconnecting and reinserting one pump is solved, an internal pump type recirculation flow rate control device with a simple configuration can be realized by dividing the internal pumps into groups and controlling them.

The basic concept of the control method of the present invention will be explained below using FIG. 6. The feature of this control method is that the pump disconnection I7
In order to avoid sudden changes in the pump rotation speed when restarting the pump,
One set of manual signal generators common to all pumps16. Signal limiter 17. Internal pump motor drive device 18. The reason is that a control device exclusively for starting and stopping consisting of a synchronizing device 19 is provided.

First, the operating method when disconnecting one pump using this control method will be explained. Assume that the internal pump PI has failed. At this time, the operator operates the manual signal generator 16 while watching the synchronizer 19, and matches the voltage and frequency of the internal pump motor drive device 18 on the start/stop control device side with the voltage and frequency on the main control device side. let When the voltages and frequencies on both sides match, the breaker 20 on the start/stop controller side is closed, and then the breaker 11 on the main controller side is tripped. By this operation, the internal pump 1 is switched to the start/stop exclusive control device side without any change in the rotational speed, and thereafter the output of the manual signal generator 16 is gradually reduced to lower the pump rotational speed. When the pump rotation speed reaches zero, the circuit breaker 20 is opened to stop the pump. At this time, if the main control device side is set to automatic operation, the deviation between the reactor output target value and Feedback No. 1a will temporarily increase for other healthy pumps, so it will be possible to reduce The rotational speed of the remaining healthy pumps increases to compensate for the decrease in core flow rate, allowing continued rated output operation as a recirculation system. If an automatic synchronizer is used in place of the manual signal generator 16, this series of operations can be performed accurately and quickly while further reducing the burden on the operator. This is because an operation is automatically performed to match the voltage and frequency of the internal pump motor drive device 18 on the start/stop dedicated control device side with the voltage and frequency on the main control device side. In addition, when a match is detected, the breaker 20 on the side of the control device dedicated to starting and stopping is turned on, and then the breaker 11 on the side of the main control device is turned on.
It is also possible to automate the operation of pulling out.

Next, we will explain how to operate the pump when the pump failure has been resolved and the pump is put into operation again. First, after confirming that the breaker 11 on the main control device side is in an open state, the breaker 20 on the start/stop control device side is turned on. The operator operates the manual signal generator 16 while looking at the synchronizer 19, and operates the internal pump motor drive device 1 on the side of the start/stop dedicated control device.
Match the output voltage and frequency of 8 with the voltage and frequency of the main controller. When the voltages and frequencies on both sides match, the breaker 11 on the main controller side is turned on, and then the breaker 20 on the start/stop controller side is tripped. With this operation, the internal pump was restarted without overshooting the rotational speed. At this time, if the main control unit side is set to automatic operation, the remaining pumps will be rotated in response to the increase in core flow rate due to the increase in the rotation speed of the pumps being reintroduced, contrary to the case of the above-mentioned shutdown. number decreases.

In this way, it becomes possible to disconnect and reinsert one pump without causing any change in the core flow rate.

Furthermore, if the rated output is allowed to decrease, it is also possible to disconnect two or more pumps at the same time and restart them.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 7th
The figure shows an example of a control system configuration in which 1.2 internal pumps are divided into two groups of 6 units each, and the control system is approximately the same scale as a conventional external loop type recirculation flow rate control system.

This control device includes a main controller 2 which receives a reactor output target value 1 from a turbine control system or an automatic power adjustment device and performs proportional-integral calculations. Main automatic/manual control switch 39 for selecting automatic operation or manual operation according to the reactor output target value; for example, a seed pack signal based on the core flow rate measured at the lower part of the reactor core or the neutron flux signal measured with a known neutron detection device. Compensator 5 receives the signal 4 and performs compensation calculation on the deviation between the reactor output target value and the feedback signal. Controller 6 which performs proportional integral calculation on the above deviation. and two sets of automatic manual control switching devices7. Controller 6 and internal pump runback signal 13
Lower controller for selecting the low value signal of 8. Signal limiter for limiting the upper limit of pump rotation speed9. a lower control device consisting of an internal pump motor drive device 10° and a breaker 11;
1 set of manual signal generators 16. Signal controller 17. Internal pump motor drive device 18. A synchronizer 19 that confirms that the voltage and frequency of the main control device and the dedicated control device for starting and stopping each pump are synchronized when starting and stopping each pump.
．． It is composed of a circuit breaker 20.

According to this embodiment of the present invention, the scale of the control device is comparable to that of a conventional external loop reactor recirculation flow rate control device.
The problem of arranging control equipment on the central monitoring control panel has also been resolved, and the burden placed on the operator during manual operation is exactly the same as that of the conventional external loop type. Furthermore, since it is possible to start and stop each internal pump, the greatest advantage of the internal pump nuclear reactor recirculation system, which is that it is possible to continue operating at rated output even if one pump fails, is retained.

The above was an example in which the internal pumps were divided into two groups and one set of control devices exclusively for starting and stopping was installed. However, as other embodiments of the present invention, a method for dividing internal pumps into groups and a control device exclusively for starting and stopping Since the number of sets of control devices to be installed is arbitrary, the control device configuration can be adapted to any group division method. In other words, the control device can flexibly respond to all demands such as the arrangement of control devices and cost.

〔Effect of the invention〕

According to the present invention, for 10 to 12 internal pumps, the conventional control device consists of one set of automatic manual control switch, lower controller, signal limiter, pump motor drive device, etc. for each pump. However, by dividing the pumps into several groups and installing one set of control devices for each group, as well as installing a control device exclusively for starting and stopping, it was possible to easily operate the same pump even if 11 pumps malfunctioned. Since it is possible to start and stop the pumps by disconnecting them from other pumps, it is no longer necessary to stop several pumps in one group at the same time, so even if a control device is installed in each group, even if one bonder malfunctions, the reactor's rating There are up to i, which have the greatest advantage of an internal pump type reactor recirculation system that can continue to operate at output.

In addition, since the control device and operation part can be reduced to an external loop platter, the problem of space for controlling equipment on the surface of the central control panel is solved, and the burden on the operator and the operation part itself can be reduced compared to the conventional internal. It has a significant reduction effect compared to the pump type.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams of the reactor vessel and internal pump, Figure 3 is a block diagram showing the configuration of the current internal pump reactor recirculation flow control system, and Figure 4 is the conventional A block diagram showing the configuration of an external loop reactor recirculation flow control device, Figure 5 is a simple application of the configuration of a conventional external loop reactor recirculation flow control device with two pumps to an internal pump type. FIG. 6 is a diagram explaining the basic concept of the control system according to the present invention, and FIG. 7 is a block diagram showing an example of the internal pump type nuclear reactor recirculation flow rate control device according to the present invention. It is a block diagram. 100... Reactor pressure vessel wall, 200... Reactor core shroud, 1... Reactor output target value, 2... Main controller, 3... Main automatic manual control switch, 4... Feedback signal, 5... Compensator, 6... Controller, 7...
Automatic manual control switch, 8... Lower controller, 9... Signal limiter, 10... Interdel pump motor drive device, 11... Breaker, 12... Internal pump, 12A.・・Internal pump motor, 13・・
- Internal pump runback signal, 14... Function generator, 15... Rake tube drive device, 16... Manual signal generator, 17... Signal limiter, 18... Internal pump motor drive Device, 19... Synchronization device, 2
0...breaker. Agent Patent Attorney Tatsuyuki Unuma

Claims (1)

[Claims] 1. In an internal pump reactor, where reactor water is forcibly recirculated by multiple pumps installed at the bottom of the gap between the reactor core shroud and the pressure vessel wall, the internal pumps are divided into several groups. One set of lower-level control equipment is installed for each group, and if a problem occurs with one pump in each group, that pump can be disconnected under the same operating conditions as the other pumps, and then A dedicated start/stop control device is common to all pumps, which causes the pump to stop when the pump recovers, and then sets the pump to the same operating conditions as the other pumps, such as voltage, and enters a cooperative state with the other pumps. A nuclear reactor recirculation flow rate control device is provided with one set in the reactor recirculation flow rate control device, and is characterized by being able to operate at rated output even if one bonder malfunctions.