JPH10253007A - Feedwater flow-rate controller of heat exchanger-type steam generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to automatically switch over without causing much variation in flow rate a main feedwater valve and a bypass feedwater valve with which a steam generator of a pressurized water reactor is jointly provided. SOLUTION: A feedwater flow-rate controller has a main feedwater valve 5, a main feedwater valve feedwater flow-rate controller 13 which is connected to the main feedwater valve 5 through a main feedwater valve control signal change-over switch 11, a bypass feedwater valve 8, a bypass feedwater valve feedwater flow-rate controller 17 which is connected to the bypass feedwater valve 8 through a bypass feedwater valve control signal change-over switch 15, and a feedwater valve automatic change-over switching controller 19 which is connected to both the feedwater flow-rate controllers 13, 17 and to their respective change-over switches 11, 15 and designed to receive feedwater flow-rate signal (w). The feedwater valve automatic change-over switching controller 19 produces in parallel to each other in terms of time valve-closing control signals which decrease the flow rate of either the main feedwater valve 5 or the bypass feedwater valve 8 at a constant rate and valve- opening control signals which increase the flow rate of the other at a constant rate so as to control the main feedwater valve 5 and bypass feedwater valve 8 simultaneously in a manner of minimizing the variation of the total feedwater flow-rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed water flow control device for a steam generator having both a large-capacity main feed valve and a small-capacity bypass feed water control valve, and more particularly, to steam generation in a pressurized water reactor. The present invention relates to a feed water flow control device for a steam generator having a shell-and-tube heat exchanger structure like a heat exchanger.

[0002]

2. Description of the Related Art A steam generator of a pressurized water reactor which is widely used as a power generation reactor at present has a structure of a large shell and tube type heat exchanger, and is supplied to a space in a trunk. The feedwater is heated by a reactor coolant flowing through the heat transfer tubes to form steam, and the generated steam is used for driving a turbine. The steam used in the turbine is condensed and supplied again to the steam generator as feed water by the feed water pump. FIG. 3 shows a water supply system diagram around the steam generator. In the figure, a water supply pipe 3 connected to a water supply pump (not shown) is connected to a steam generator 1, and a main water supply valve 5 is attached to the water supply pipe 3. Furthermore, a bypass water supply line 7 is provided around the main water supply valve 5, and a bypass water supply 8 is provided in the bypass water supply line 7. A main steam pipe 9 extends from the ceiling of the steam generator 1 and communicates with a steam turbine (not shown). Then, the feedwater supplied to the steam generator 1 through the feedwater pipe 3 is heated as described above, turns into steam and flows out of the main steam pipe 9, but uses the main feedwater valve 5 or the bypass feedwater valve 8. The feedwater flow rate is adjusted so that the water level in the steam generator 1 falls within a predetermined range. That is, when the steam flow rate and the water supply flow rate are high and the load is high, the bypass water supply valve 8 is closed, and the main water supply valve 5 is adjusted by a valve control degree (not shown) to adjust the water supply flow rate. On the other hand, when the steam flow rate and, consequently, the feedwater flow rate is low and the load is low, the main feedwater valve 5 is closed, and the bypass feedwater valve 8 is controlled by a feedwater flow controller (not shown) to adjust the feedwater flow rate.
When the load rises or falls, both the main water supply valve 5 and the bypass water supply valve 8 are manually operated,
The water supply valve is being switched.

[0003]

As described above, when the load is increased or decreased, the main water supply valve 5 and the bypass water supply valve 8 are manually switched to each other. there were. Then, the fluctuation of the supply water flow rate causes the fluctuation of the water level in the steam generator, and there is a possibility that the moisture of the generated steam may increase and a unit trip of related equipment may occur. Accordingly, the present invention provides an automatic control device that can smoothly switch between these two water supply valves without causing a large flow rate fluctuation in a steam generator in which a main water supply valve and a bypass water supply valve are provided in a water supply pipe. An object of the present invention is to provide a feedwater flow control device for a heat exchanger type steam generator provided with the same.

[0004]

In order to solve the above problems, according to the present invention, a feed water flow control device for a heat exchanger type steam generator is provided with a steam flow rate indicating a steam amount of steam emitted from the steam generator. Using a signal, a feedwater flow signal representing the amount of water supplied to the steam generator, and a steam generator water level signal representing the water level of the steam generator, the steam generator water level signal is kept within a predetermined suitable range. A main water supply valve provided in a water supply pipe of the steam generator, the main water supply valve being connected to the main water supply valve via a first switch to receive a steam flow rate signal, a feed water flow rate signal, and a water level signal. A main water supply valve water supply flow rate controller for generating an opening degree adjustment signal, a bypass water supply valve provided in a bypass water supply pipe that bypasses the main water supply valve, and the bypass water supply valve connected to the bypass water supply valve via a second switching device; Open when receiving water supply flow rate signal and water level signal A water supply valve having a bypass water supply valve water supply flow rate controller for generating an adjustment signal, communicating with the two water supply flow rate controllers, communicating with the first and second switching devices, and further receiving a water supply flow rate signal. Equipped with a switching control device,
This water supply valve switching control device temporally converts a valve closing control signal for decreasing the flow rate of one of the main water supply valve and the bypass water supply valve at a constant rate and a valve opening control signal for increasing the other flow rate at a constant rate. The main water supply valve and the bypass water supply valve are simultaneously controlled so as to occur in parallel and minimize the fluctuation of the total water supply flow rate.

[0005]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The same reference numerals denote the same parts or portions throughout the drawings including the above-described drawings. In FIG. 1, a main water supply valve 5 provided in a water supply pipe 3 connected to a steam generator (not shown) is electrically connected to a first switch, that is, a main water supply valve control signal switch 11, and further a main water supply. The valve control signal switch 11 communicates with the main water supply valve water supply flow controller 13. The main water supply valve water supply flow controller 13 includes a steam flow signal s from a flow detector provided in a main steam pipe (not shown), a water supply flow signal w from a flow detector provided at an appropriate position of the water supply pipe 3, and A steam generator water level signal h from a water level detector provided in the steam generator is input. The control method of the main water supply valve water supply flow rate controller 13 is a so-called 3
In the element control, the water supply amount flowing out as steam is supplemented by a newly supplied water supply amount, and further adjusted by a water level signal based on a difference between an actual water level and a set water level, which is a normal one.

On the other hand, the bypass feed valve 8 provided in the bypass feed pipe 7 is connected to a second switch, that is, a bypass feed valve control signal switch 15, which is further connected to the bypass feed valve feed water flow controller 17. I'm in contact. The bypass water supply valve water supply flow control 17 includes a main water supply valve water supply flow controller 1.
3, the steam flow signal s, the feedwater flow signal w, and the steam generator water level signal h are input. The control operation of the bypass water supply valve water supply flow rate control 17 is the same as that of the main water supply valve water supply flow rate controller 13, and the difference between the two is only the magnitude of the flow rate. The main water supply valve control signal switch 11 and the bypass water supply valve control signal switch 15 are provided with an automatic water supply valve switching control device 19 for switching these connection states and adjusting the valve opening of each water supply valve.
Has contacted. That is, the switching command signal m and the valve opening degree adjustment signals n and p are input from the water supply valve automatic switching control device 19 to the main water supply valve control signal switch 11 and the bypass water supply valve control signal switch 15. . The water supply valve automatic switching control device 19 is also provided with the main water supply valve water supply flow controller 13.
And the bypass water supply valve water supply flow rate control 17, and also receives the above-mentioned water supply flow rate signal w. In addition, the water supply valve automatic switching control device 19 is in communication with a switching start operation device 21 and a switching start permission indicator lamp 23 to operate itself.

Next, a description will be given of an example in which the water supply valve is switched from the main water supply valve 5 to the bypass water supply valve 8 with reference to FIG. The switching permission condition, that is, within the set water supply flow rate, the main water supply valve 5 is in the automatic control state, and the bypass water supply valve 8
Is satisfied, that the switch start permission indicator lamp 23 is on, and the switch start operating device 21
Is operated, the water supply valve automatic switching control device 19 starts operating. First, a switching command signal m is output and input to the main water supply valve control signal switch 11 and the bypass water supply valve control signal switch 15, and the valve opening degree adjustment signals n and p from the automatic switching control device 19 are supplied to the main water supply valve 5. The internal connection state is switched so as to be input to the bypass water supply valve 8 and the bypass water supply valve 8, respectively. Then, the valve opening adjustment signal p for the bypass water supply valve 8 is 0%
From (fully closed) to the target value calculated from the main water supply valve control signal in the automatic control state, the rate increases at a previously adjusted rate of change (from point a to point c). When the valve opening adjustment signal p is applied to the bypass water supply valve 8, the valve starts to open with a predetermined delay, and the valve lift follows the valve opening adjustment signal p to indicate the dashed curve q
Increase as shown in FIG. When the actual start of opening of the bypass water supply valve 8 is detected from the valve lift q as a bypass water supply valve opening detection signal (point b), the rate of change is 0% at a preset rate of change.
The valve opening adjustment signal n for decreasing the valve opening until (fully closed) is output and applied to the main water supply valve 5 via the main water supply valve control signal switch 11. The valve lift r of the main water supply valve 5 follows the valve opening adjustment signal n with a delay. Valve opening adjustment signal p
Keeps the target value for a predetermined time from when the target value is reached until the actual valve opening catches up (from point c to point d). Then, the feedwater flow signal w stored at the start of the switching and the point d
The valve opening adjustment signal p rises or falls in accordance with the deviation from the feed water flow signal w at the point of time. When the switching state ends, the state is switched to the normal automatic control state (point e). The switching from the bypass water supply valve 8 to the main water supply valve 5 is performed by using the bypass water supply valve 8 and the main water supply valve 5 in the above description.
Are interchanged, so that those skilled in the art can easily understand.

[0008]

As described above, according to the present invention,
Since the main water supply pipe attached to the water supply pipe of the steam generator and the bypass water supply pipe are automatically controlled and switched so as to open or close automatically, a smooth automatic supply without significant fluctuation in the water supply flow during that time. Control switching can be performed.

[Brief description of the drawings]

FIG. 1 is a control system diagram according to an embodiment of the present invention.

FIG. 2 is a graph for explaining the operation of the embodiment.

FIG. 3 is a conceptual diagram of a water supply system around a steam generator according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 steam generator 3 water supply pipe 5 main water supply valve 7 bypass water supply pipe 8 bypass water supply valve 11 main water supply valve control signal switch 13 main water supply valve flow controller 15 bypass water supply valve control signal switch 17 bypass water supply valve flow controller 19 Water supply valve automatic switching control device 21 Switching start operation device 23 Switching start permission indicator lamp

Claims (2)

[Claims] 1. A steam flow rate signal indicating a steam flow rate of a steam generator, a feed water flow rate signal indicating a feed water flow rate supplied to the steam generator, and a water level signal indicating a water level in the steam generator. In the feed water flow control device for a steam generator, a main feed valve provided in a feed pipe of the steam generator, the main feed valve connected to the main feed valve via a first switch, and the steam flow signal, the feed water flow signal, and the water level signal. , A main water supply valve water supply flow rate controller that generates a valve opening adjustment signal in response to the above, a bypass water supply valve provided in a bypass water supply pipe that bypasses the main water supply valve, A bypass feedwater valve feedwater flow controller for communicating with the steam flow signal, the feedwater flow signal, and the water level signal to generate a valve opening control signal; Contact and receive the feedwater flow signal A water supply valve automatic switching control device, wherein the water supply valve automatic switching control device reduces the flow rate of one of the main water supply valve and the bypass water supply valve at a constant rate. A signal and a valve opening control signal for increasing the other flow rate at a constant rate are generated in parallel in time, and the main water supply valve and the bypass water supply valve are simultaneously controlled so that the fluctuation of the total water supply flow rate is minimized. A feedwater flow control device for a heat exchanger-type steam generator, wherein 2. The water supply valve switching control device according to claim 1, wherein the water supply flow signal at the start of operation is stored, and after the switching is completed, the open water supply valve is controlled in accordance with the water supply flow deviation before and after the switching operation. A feedwater flow control device for a heat exchanger-type steam generator as described in the above.