JPS60135899A - Method of controlling feedwater to 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 a reactor feed water control method in a nuclear power plant having a plurality of water supply loops, and in particular, the total feed water flow rate is determined by the feed water pump discharge pressure. The present invention relates to a reactor feed water control method in which the loop-specific feed water flow rate is controlled by the water level of a drum or a steam generator, respectively.

[Background of the invention]

FIG. 1 shows an example of a plant control system for one loop in an ATR nuclear power plant, and various control systems are provided to control the power generation output.

In other words, the main system of the ATR nuclear power plant is the reactor 1, drum 3, recirculation pump 4, feed water pump 5, and steam turbine 8.
, a condenser 9, and a generator 10, and various control systems are provided to control the power generation output for the main system thus constructed. These control systems include a load request generation control device 21, a reactor power control device 22, a drum water level control device 23, and a feed water differential pressure control device 24.
and turbine controller 25t - centrally configured;
Of these, the load request creation control device 21 receives generator output signals (
MW), the main steam pressure signal (P), and the power supply station command signal to create load request signals Ql and Q2. In addition, the reactor power control device 22 also outputs a load request signal Q.
The control rod driving device 2 is driven based on the neutron flux signal (n) from the nuclear reactor 1, and the reactor output is thereby controlled. The drum water level control device 23 also controls the water level of the drum 3 by adjusting the opening degree of the water supply control valve 7 based on the drum water level signal (L), the main steam flow rate signal (F), and the water supply flow rate signal (F). It becomes.

Furthermore, the feed water differential pressure control circuit 24 controls the feed water differential pressure (
The turbine controller 25 also controls the main steam pressure signal (P), the load request signal Q
2. The main steam control valve 1 is activated by the turbine rotation speed signal (8).
3. The opening degree of the bypass valve 14 is adjusted. Note that feed water heaters are provided between the condensate pump 11 and the water feed pump 5, and between the water feed pump 5 and the water feed ladder 6, respectively.

FIG. 2 specifically shows the configuration of the water supply control system in the above configuration, that is, the drum water level control system and the water supply differential pressure control system. According to this, the water level in the steam drum must be kept within permissible limits regardless of the load, the drum water level corresponding to the loop is controlled by operating the loop water supply control valve, and the total water supply flow rate supplied to each loop is controlled by operating the loop water supply control valve. is controlled by adjusting the rotation speed of the water supply pump.

That is, in order to control the water level of the drum 3, the water level detector 41
The drum water level signal from the drum water level signal... is compared with the water level set value from the setting circuit 34a by the adder 35a via the pressure correction circuit 31, and the deviation is determined by the water level controller 36a.
Adder 35 via 1 manual/automatic switching station 37a
b. This adder 35bK
In addition, the main steam flow rate signal from the steam flow rate detector 43 is passed through the steam flow rate signal density correction circuit 32, and the feed water flow rate signal from the feed water flow rate detector 42 is further passed through the feed water flow rate signal density correction circuit 33 as shown in the figure. It is now entered. The water level of the drum 3 is controlled by the addition result of the three inputs in the adder 35b by adjusting the opening degree of the loop water supply control valve 7a via the water level controller 36b1 manual/automatic switching station 37C1 electro-pneumatic converter 38a. This is what has become. In addition, in order to control the total amount of water supplied to each loop, the deviation of the water supply header pressure signal and the main steam pressure signal from the pressure detectors 44 and 45 is determined by the adder 35C, and the deviation and the setting circuit 34b are calculated. The deviation from the set value of the water supply differential pressure is calculated by an adder 35d. The differential pressure controller 36d is controlled by the output of the adder 35d.
1. The rotational speed of the turbine-driven water supply pumps 5b, 5C is controlled via manual/automatic switching stations 37d, 37e and rotational speed control devices 39a, 39b. In addition, at the time of startup, the water level of the drum 3 is controlled by the water level controller 936.
a is manual/automatic switching station 37b1 electro-pneumatic converter 3
It is controlled by adjusting the opening degree of the loop water supply control small valve 7b via the loop water supply control valve 7b. In addition, a starting water supply control is provided at the outlet of the motor-driven water supply pump 5a so that the water supply header pressure becomes a predetermined pressure using the setting circuit 34C1 adder 35eXfl = pressure controller 36C1 manual/automatic switching station 37f and power converter 38c. The opening degree of the valve 15 is adjusted.

Conventionally, water supply control has been performed as described above, but the water supply control system is unnecessarily complex and consists of many components, so it is difficult to improve reliability. Not only is this impossible, but it is also economically disadvantageous. Furthermore, since the control force method is different between startup and steady operation, the control system becomes even more complicated, or there is a potential risk of erroneous operation. Furthermore, due to fluctuations in the drum water level,
When the loop water supply control valve is operated, the water supply differential pressure changes, and the rotation speed of the turbine-driven water pump is therefore controlled. However, this effect is fed back to the drum water level, so that the loop water supply When the control valve is operated again, the drum water level control system, which is a loop water supply flow rate control system, and the water supply differential pressure control system, which is a total water supply flow rate control system, strongly interfere with each other.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a reactor feed water control method in which a loop feed water flow rate control system and a total feed water flow rate control system can be economically configured with a low risk of erroneous operation, and in which interference between these control systems can be reduced. It is to provide.

[Summary of the invention]

For this purpose, the present invention is designed so that the total water supply flow rate is controlled in advance so that the water supply pump discharge pressure is in accordance with the load, while the loop water supply flow rate is controlled when the drum water level or the steam generator water level is at a specified water level. It is designed to be controlled as much as possible.

More specifically, the total water supply flow rate is determined based on the load demand command by controlling the opening of the water supply control valve for starting the motor-driven water supply pump at startup, and by proactively controlling the rotation speed of the turbine-driven water supply pump at non-startup. In addition, the loop water supply flow rate is stably controlled by controlling the opening degree of the loop water supply control valve based on changes in the water level so that the drum water level or the steam generator water level reaches the specified water level. It is.

[Embodiments of the invention]

The present invention will be explained below with reference to FIGS. 3 and 4.

The present invention is applicable to nuclear reactor plants where water is supplied to multiple loops, such as ATR nuclear power plants where water is supplied to a reactor core divided into multiple loops, and multiple steam generator water levels where reactor heat is transferred. It can generally be applied to FBR nuclear power plants, PW 几 nuclear power plants, etc., which have a system configuration in which water is supplied to people.

Now, the configuration of an example of the control system according to the present invention will be explained using FIG. 3 using an ATR nuclear power plant as an example. The control system includes a water supply header pressure control system that controls the total water supply flow rate, and a loop compatible system. The drum water level control system maintains the drum water level at a specified water level by adjusting the flow rate of water supplied to the loop.

First, the water supply header pressure control system will be described. Based on the load request command from the load request generation control device 51, the water supply header pressure request signal' is generated from the function generator 40a. Figure 4 shows the Q (flow rate) - H (header pressure) characteristics of a turbine-driven water pump. Once the flow rate is determined, it passes through the intersection point with the water supply header pressure demand curve A, the water supply header pressure, and then the intersection point. The water supply pump rotation speed curve C indicates the rotation speed of the water supply pump. If the flow rate becomes smaller than the flow rate, the water supply pump rotation speed curve C shifts to the water supply pump rotation speed curve. In addition, B and E in FIG. 4 indicate the system pressure loss curve and the main steam pressure, respectively.

Now, the deviation between the water supply header pressure request signal from the function generator 40a and the water supply header pressure signal from the pressure detector 44 is determined by the adder 35f, and the pressure controller 36e1 manual/automatic switching station The opening degree of the start-up water supply control valve 15 is controlled at the time of start-up via 37d to 37f. When not activated, the turbine-driven water supply pump 5b.

The rotation speed of 5C is controlled in this way. Specifically, when the load is about 30% or less, the start-up water supply control valve 15 is controlled, and when the load is about 30% or more, the turbine-driven water supply pumps 5b and 5G are controlled. In this case, the adder 35g includes a steam flow rate detector 5.
A load-equivalent main steam flow signal from 2 is added to improve response.

Next, to explain the drum water level control system, the drum water level signal from the water level detector 41 is compared with the water level set value in the adder 35a, and the opening degree of the loop water supply control valve 7 is adjusted and controlled based on the deviation. By the way, this is true.

However, when using these control systems, when the load changes, the water supply header pressure control system performs proactive control to maintain the superimposed balance between the main steam flow rate and the water supply flow rate, while in each loop, the system Fluctuations in the drum water level caused by differences in characteristics can be suppressed by fine-tuning the drum water level control system while minimizing mutual interference, making stable total water supply flow rate control and loop water supply flow rate control possible. It is what it is. In addition, since the control aspects are unified during startup and steady output operation, operational operability is greatly improved, and water supply flow rate control can be performed economically by simplifying the system configuration. This is the result.

〔Effect of the invention〕

As explained above, the present invention allows the total water supply flow rate to be controlled in advance so that the water supply pump discharge pressure is in accordance with the load, regardless of whether it is at the time of startup or not, and
The loop water supply flow rate is controlled based on changes in the drum water level or the steam generator water level so as to maintain the specified allowable water level. Therefore, according to the present invention, the water supply flow rate control system not only has improved operability, but also can be configured economically, and furthermore, it is possible to control the water supply flow rate while suppressing mutual interference. Effects can be obtained.

[Brief explanation of drawings]

Figure 1 is a diagram showing an example of a plant control system in an ATEt or nuclear power plant for one loop, Figure 2 is a diagram specifically showing the configuration of the water supply control system in that configuration, and Figure 3 is FIG. 4 is a diagram specifically showing the configuration of an example of the water supply control system according to the present invention, and FIG. 4 is a diagram showing the flow rate and pressure characteristics of the water supply pump system. 1i゛... Nuclear reactor, 3... Drum, 5a... Motor driven water supply pump, 5b, 5C'-Turbine driven water supply pump, 6... Water supply header, 7 (7a)... Loop water supply control valve , 15...Start-up water supply control valve, 34a...(
Setting circuit (for setting water level), 35a... Adder (for detecting water level deviation), 35f... Adder (for detecting required pressure deviation), 41... Water level detector, 44... Pressure detector, 51
...Load request creation control device. Agent Patent Attorney Masami Akimoto f] 2 Figures 4th - q7 He Shima

Claims (1)

[Claims] 1. A reactor water supply control method in a nuclear reactor plant having a system configuration in which water is supplied to each of a plurality of steam generators or each of a reactor core divided into a plurality, in which the total water supply flow rate is The flow rate is controlled in advance by controlling the startup water supply control valve and the water pump so that the water supply pump discharge pressure is in accordance with the load command, while the loop water supply flow rate is determined by the drum water level or steam generator water level. 1. A reactor water supply control method, characterized in that the flow rate is controlled by controlling the opening degree of a loop water supply control valve based on changes in water level to maintain an allowable water level. 2. In controlling the total water supply flow rate, the opening degree of the startup water supply control valve on the outlet side of the motor-driven water supply pump is controlled during startup, and the rotation speed of the turbine-driven water supply pump is controlled during non-startup. A nuclear reactor feed water control method according to claim 1.