JPS6214095A - Controller for pressure and water level of 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 [Technical Field of the Invention] The present invention relates to a nuclear reactor pressure and water level device,
In particular, the present invention relates to a reactor pressure and water level control device I that controls the pressure and water level during reactor startup and shutdown of a boiling water reactor.

[Technical background of the invention and its dark problems]

Generally, a boiling water reactor is configured as shown in FIG. 3, and when the reactor is started, the pressure inside the reactor pressure vessel 1 is increased at a constant rate. Therefore, while the reactor water in the reactor pressure vessel 1 undergoes thermal expansion, the cooling water 2 in the control rod drive mechanism housing flows into the reactor pressure vessel 1 due to handling of the control rods. As a result, the reactor water level rises, and the excess reactor water is transferred to the reactor coolant purification pump 3,
It is discharged to the main condenser 8 through the discharge piping 7 of the atomic or cold W material purification system consisting of the regenerative heat exchanger 4, the non-regenerative heat exchanger 5, and the filtration demineralizer 6.

On the other hand, the main steam pipe 10 connected to the main turbine 9 is provided with a main steam drain pipe 11 that drains water from the main condenser 8 after filling the main trachea 10 with water during the first periodic inspection. There is. The main steam drain pipe 11 is operated with all main steam drain valves 12 open in order to discharge water droplets in the main steam pipe 10 to the main condenser 8 at the time of reactor startup. Therefore, at the time of reactor startup, as the reactor pressure increases, the amount of reactor steam m discharged from the main steam drain pipe 11 to the main condenser 8 increases.

As a result, when the reactor pressure in the reactor pressure vessel 1 reaches a certain level or higher, the reactor steam flow ω released to the main condenser 8 is caused by the expansion of the reactor water and cooling from the it, II i11 rod drive housing. Since the amount of water increases compared to the amount of water used in the second round, in order to keep the reactor water level constant, it is necessary to supply condensate from the main condenser 8 using the water supply pump 13.

Also, at the time of reactor startup, a feed water heater 1 that heats the feed water is installed.
5 is not operating, so the water supply temperature is room temperature. Therefore, the return pipe 16 of the reactor coolant purification system is connected to the water supply pipe 14, and the water supply from the main condensate Z8 and the return reactor water close to the reactor water temperature from the reactor cold W material purification system are connected. Mix and reactor pressure content 2! The temperature of the water supplied to i1 is increased. This reduces the influence of thermal stress on the feed water sparger 17 installed in the reactor pressure vessel 1 due to the temperature difference between the reactor water and the feed water.

However, the feed water flow rate is determined by the reactor steam discharged to the main condenser 8 in the uncontrolled main air drain piping 10, and when the reactor pressure is high, the reactor steam flow is determined by the reactor steam discharged into the reactor coolant purification system. The flow rate of the return reactor water is larger than that of the return reactor water, and the effect of contributing to an increase in the moisture content of the feed water due to the calorific value of this return reactor water is reduced.

On the other hand, when the nuclear reactor is shut down, the large-capacity turbine bypass valve 18 is opened to release reactor steam to the main condenser 8 through the turbine bypass path, thereby depressurizing the reactor. At this time, all of the main steam drain valves 12 of the main steam drain pipe 11 are also released in the same manner as at the time of reactor startup, and are used in combination with the turbine bypass valve 18, contributing to the pressure reduction of the reactor.

However, since the turbine bypass valve 18 is human-sized, it is difficult to control the pressure R11 of the reactor with a high Iff degree.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned circumstances, and it is possible to minimize the thermal influence on the feed water sparge 11 at the time of reactor startup, and to control the reactor pressure and pressure with high viscosity at the time of reactor shutdown. The purpose is to provide a water level control device.

[Summary of the invention]

In order to achieve the above-mentioned object, the reactor pressure and water level υ control device according to the present invention has a main steam pipe that supplies steam generated in the reactor pressure vessel to the main turbine, and a main steam pipe that supplies the steam generated in the reactor pressure vessel to the main turbine. A main condenser for condensation, a main steam drain pipe for releasing the natural air in the reactor pressure vessel from the main steam piping to the main condenser, and a main steam drain pipe for supplying condensate in the main condenser to the reactor pressure vessel. In a system having a water supply pipe and a discharge pipe for discharging reactor water in the reactor pressure vessel to the main condenser, a water level detector for detecting the water level in the reactor pressure vessel, and a water level detector for detecting the water level in the reactor pressure vessel; A pressure detector for detecting the pressure inside the furnace, and a flow ff1 installed in the main steam drain pipe, water supply pipe, and discharge pipe by receiving the detection signals from both of these detectors.
The controller is characterized in that it has a controller that outputs a valve opening degree tAlXl signal of the M control valve.

By doing this, the main steam G from the reactor pressure vessel and the feed water ω are balanced to control the reactor water level at a constant level, and the main steam m from the reactor pressure vessel is accurately maintained at ail+ within the microflow ffi range. The pressure Il control characteristics of a nuclear reactor with high refinement can be obtained.

(Embodiment of the Invention) Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 20 indicates a reactor pressure vessel housed in a reactor containment vessel 21, and this reactor pressure vessel 2
0 contains reactor water 22 as a coolant, and this reactor water 2
2 holds a reactor core (not shown) in an immersed state. The reactor pressure vessel 20 is connected to a main turbine 24 via a main steam pipe 23, and the reactor pressure vessel 20 is connected to a main turbine 24 via a main steam pipe 23. ! The main steam generated by J20 is supplied to the main turbine 24 to do work. The main steam pipe 23 has a main air wAfIA valve 2.
5.25, a main steam stop valve 26, a main steam control valve (not shown), etc. are provided.

The steam that has done work in the main turbine 24 is condensed and condensed in the main condensate 15i27, while this condensate is transferred to the water supply pipe 28.
The reactor pressure 15 is supplied into the reactor pressure reactor 20 through . The water supply pipe 28 includes a water supply pump 29 and a water supply valve 3.
0. A condensate pump, demineralizer, feed water heater, etc. (not shown) are provided. Then, by opening the water supply valve 30 and the like and operating the water supply pump 29, the condensate from the main condenser 27 passes through the water supply pipe 28 and is supplied from the water supply sparger 31 into the reactor water of the reactor. It has become.

In addition, a main steam drain pipe 33 is branched from the upstream side of the main steam isolation valve 25 of the main steam pipe 23 or between the main steam isolation valves 25 and 25 that form a pair, and this main steam drain pipe 33 is branched as necessary along the way. and is connected to the main condensate 2927. A plurality of main steam drain valves 34 are arranged in parallel in the main steam drain piping 33, and these main steam drain valves 3
From 4.31 onwards, it will be opened when the reactor starts up.

On the other hand, a reactor coolant purification system consisting of reactor water 22G in the reactor pressure vessel 20, a reactor coolant purification pump 35, a regenerative heat exchanger Pli 36, a non-regenerative heat exchanger 37, and a filtration desalination device 38 /J\ It is purified at 40. This reactor coolant purification system 40 discharges excess water when the reactor water level rises through a pipe 41 to the main water! ! The reactor water is discharged to S27, and high-temperature reactor water is sent to the water supply pipe 28 via the return pipe 42 to raise the temperature of the normal temperature water supply.

The water level inside the reactor pressure vessel 20 is detected by a water level detector 44.
The pressure inside the reactor pressure vessel 20 is detected by a pressure detector 45 provided upstream of the turbine stop valve 26. These water level detection if! i44, water level signal A as a detection signal detected by the pressure detector 45
, pressure signal 8 (Y) is input to the controller 46.

This controller 46 controls the flow fafI1 provided in the main steam drain pipe 33, the water supply pipe 28, and the discharge pipe 41.
The 11m valve is controlled by the wI clause.

Specifically, the controller 46 controls the valve opening degrees of the main steam drain valve 34 provided in the main steam drain piping 33, the small water supply valve 47 of the water supply piping 28, and the reactor water release valve 48 of the discharge piping 41 according to the valve opening degree f. /IwJ signals C, D, E: 1JWIυ
There are 1111. Note that the small water supply valve 47 is installed in a bypass line that bypasses the water supply valve 30.

These i11 control signals C, D, and E outputted from the controller 46 are used to open the water supply small valve 47 to inject water into the reactor pressure content 'a20 when the reactor water level drops, and to When the reactor water level rises, the main steam drain valve 34 and reactor water release valve 48 are opened to release reactor steam or reactor water to the main condenser 27. However, the main steam drain valve 34 is opened in priority to the reactor water release valve 48.

Further, the main steam drain valve 34 is configured to open in response to the pressure detection signal B of the pressure detection 345 even when the reactor pressure increases. In this case, the opening degree of the main steam drain valve 34 can be controlled by the controller 46 so that the reactor pressure increases and decreases at a constant rate.

Next, the effect will be explained. At reactor startup, the reactor water level rises to FJ due to the heat 111 of the reactor water 22 in the reactor pressure vessel 20 and the flow of cooling water 50 in the control rod drive fIJ mechanism housing into the reactor pressure vessel due to the withdrawal of the control rods. do.

The upper back of this reactor water level is detected by the water level detector 44,
The water level detection signal Δ is input to the controller 46.

In response to this human power signal, the controller 46 sets the valve opening degree tII.
The output signal C causes the main steam drain valve 34 to open. Furnace steam is discharged to the main condenser 27 by opening the main steam drain valve 34 . Also,
The controller 46 also outputs a valve opening 1jllll signal E, and this control signal E opens the reactor water release valve 48.
Reactor water is discharged into the main condenser 27. As a result, the rise in the reactor water level is controlled by i,11. If the furnace pressure is low, use this! Even if the pressure detection signal B from the pressure sensor 45 is input to the controller 46 and the main steam drain valve 34 is opened preferentially by the steam 1-control signal C from the controller 46, Since the amount of reactor steam to be released is small, reactor water is preferentially released from the reactor water release valve 48.

When the reactor pressure increases and the amount of reactor steam released from the main steam drain valve 34 increases, the release of reactor water from the reactor water release valve 48 is stopped, and the flow rate of reactor steam released from the main steam drain valve 34 is The thermal expansion of the reactor water and the flow rate of the cooling water 50 accompanying control rod withdrawal are balanced. In this case, only when the reactor water level fluctuates due to the operation of the vIII rod, the water level signal A from the water level detection ^44 that detects this is input to the controller 46, and the water supply control signal @D output from the controller 46 is used to detect the fluctuation. The small water supply valve 47 is opened, and condensate from the main condenser 27 is supplied.

FIG. 2 shows changes in reactor pressure due to the reactor water discharge flow rate and the condensate feed water flow m during reactor startup performed in this manner in comparison with the conventional example. In this FIG. 2, a is the discharge flow rate, b is the water supply flow rate according to the present invention, and C
is the water supply flow rate according to the conventional example, and as is clear from this, the water supply flow rate can be limited.

Therefore, by controlling the flow rate of reactor steam discharged from the main steam drain pipe 33, unnecessary injection of feed water into the reactor pressure vessel 20 can be avoided! It will be possible for the 11th period,
This is extremely favorable for improving the health of the water supply sparge 1-31.

On the other hand, when the reactor is shut down, the reactor pressure inside the reactor pressure vessel 20 is detected by the pressure detector 45, and this detector (5
B is input to the controller 46.

This input causes the steam control signal C to be sent from the controller 46.
is output, and this control signal C causes the main steam drain valve 34
The valve opening degree of the reactor is adjusted and controlled so that the pressure reduction rate of the reactor remains constant. This enables highly accurate pressure control, unlike the conventional case of controlling the valve rMa of a large-capacity turbine bypass valve.

However, since the furnace steam flow m discharged to the main condenser 27 via the main steam drain piping 33 is sufficiently smaller than the main steam flow rate discharged by the turbine bypass valve, the main steam drain steam flow rate is controlled. What this means is that the pressure fj is extremely high in opening compared to 1) 11Il due to the turbine bypass valve.
lllll becomes possible.

As a result, it is possible to minimize pressure fluctuations in the reactor pressure vessel 20 during reactor shutdown, and the pressure fluctuations in the reactor pressure vessel 20 due to fluctuations in the temperature of the cold U1 material accompanying fluctuations in the reactor pressure can be minimized.
0 It is possible to obtain the effect of reducing repeated thermal stress on other members.

〔Effect of the invention〕

Since the present invention is structured as described above, there is no need to supply water at the time of reactor startup, and it is possible to minimize the cost of thermal stress caused by the water supply sparge V due to water supply.

On the other hand, when the reactor is shut down, the high viscosity pressure aJ+
By enabling control, pressure fluctuations can be minimized, and thermal stress on the reactor pressure vessel and other components due to fluctuations in coolant temperature due to fluctuations in reactor pressure can be reduced, among other excellent effects. play.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an embodiment of the present invention, and Fig. 2 shows changes in reactor water discharge flow rate and condensate feeder flow rate due to reactor pressure at reactor startup in comparison with a conventional example. The graph shown in FIG. 3 is a system diagram of a conventional example. 20... Reactor pressure vessel, 23... Main steam piping, 2
4... Main turbine, 25... Main steam isolation valve, 27...
...Main condenser, 28...Water supply pipe, 29...Water supply pump, 30...Water supply valve, 31...Water supply sparger,
33... Main steam drain piping, 34... Main steam drain valve, 35... Reactor coolant pump, 36... Regenerative heat exchange 4.37... Non-regenerative heat exchanger, 38...・Filtration desalination equipment, 41...Discharge piping, 42...Return piping, 4
4...Water level detector, 45...Pressure detector, 46...
- Controller, 47... Small water supply valve, 48... Reactor water release valve. "---'---"----"'IFigure 1Figure 2rIA Figure 3

Claims (1)

[Claims] 1. Main steam piping that supplies steam generated in the reactor pressure vessel to the main turbine, a main condenser that condenses the steam that has done work in the main turbine, and atoms from the main steam piping. A main steam drain pipe that releases steam in the reactor pressure vessel to the main condenser, a water supply pipe that supplies condensate in the main condenser to the reactor pressure vessel, and a main steam drain pipe that releases the steam in the reactor pressure vessel to the main condenser. A water level detector that detects the water level in the reactor pressure vessel, a pressure detector that detects the in-core pressure in the reactor pressure vessel, and a pressure detector that detects both of these, in a device that has a discharge pipe that discharges to a water container. and a controller that inputs a detection signal from the reactor and outputs a control signal for controlling the valve opening of the flow control valve provided in the main steam drain pipe, the water supply pipe, and the discharge pipe. and water level control devices. 2. Each flow control valve consists of a main steam drain valve whose valve opening is controlled by a steam control signal output from the controller, and a small water supply valve whose valve opening is controlled by a water supply control signal from the controller. The reactor pressure and water level control device according to claim 1, which is a reactor water release valve whose opening degree is controlled by a release control signal from the controller. 3. When the reactor water level drops, the controller opens the flow control valve installed in the water supply pipe, and when the reactor water level rises, the flow control valve installed in the main steam drain pipe opens the flow rate control valve installed in the discharge pipe. A nuclear reactor pressure and water level control device according to claim 1, which outputs a control signal for preferentially opening a control valve. 4. The controller is configured to output a control signal to open a flow control valve provided in the main steam drain pipe when the reactor pressure increases. Water level control device.