JPS6159296A - Nuclear power plant - 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 power plant, and more particularly to a nuclear power plant in which the Ti-like output from a turbine follows load fluctuations of relatively small width and rapid period.

(Technical background of the invention and other points) In general, compared to thermal power plants, atomic saw power plants have relatively low operating costs such as fuel costs compared to construction costs. As a load, it is often operated at a constant output around the rated output.

However, in recent years, as the proportion of nuclear power generation in the total power generation capacity has increased, it has become necessary to control the power generation of nuclear power plants in accordance with load fluctuations. There are two types of load fluctuations: those with relatively large fluctuation ranges and variable periods, and those with small fluctuations and short periods. A follow-up driving method is required. In general, in boiling water nuclear power plants, pressure changes in the system do not affect the output and have positive feedback, so system pressure control is important, and in conventional nuclear power plants, the pressure control system is the main control system. It forms a system.

Further, when the turbine generator output is made to follow relatively slow load fluctuations, the following ability of this conventional pressure control system is sufficient. In other words, the load fluctuation range is relatively large,
For example, for load fluctuations with slow cycles of several minutes or more, the load fluctuations are detected by detecting changes in the system frequency (turbine rotation speed), and the main steam control valve is adjusted as appropriate according to this load fluctuation.
By controlling the amount of main steam flowing into the turbine, the turbine generator output was made to follow. but,
For example, if the main steam inflow a into the turbine is increased, the pressure in a boiling water reactor decreases, the void m decreases, and the reactor output decreases. Therefore, in order to reduce the main steam inflow m to the turbine (!l), it is necessary to increase the steam generated in the reactor (reactor output) in advance; This requires manual control rod operations and cannot be controlled in a short period of time.In other words, the turbine generator output is made to follow load fluctuations that fluctuate at relatively fast cycles of several tens of seconds or less, which is called governor-free operation. In order to achieve this, it is necessary to consider the magnitude of the dynamic time constant of the boiling water reactor output.

Therefore, for load fluctuations that have a relatively small width and a fast fluctuation period, it is necessary to keep the reactor pressure constant so that it does not fluctuate even if the main steam flow to the turbine fluctuates. This is necessary, and countermeasures must be considered on the main steam consumption side.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and it is possible to follow the turbine generator output without changing the reactor output when the load fluctuation width is relatively small and the load fluctuation fluctuates at a fast cycle. The purpose is to provide nuclear power plants.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention is configured as follows.

In a nuclear power plant in which main steam generated in a nuclear reactor is introduced to a turbine via a main steam flow path in which a main steam control valve is installed, a main steam flow path upstream of the main steam control valve is provided. is connected to the condenser of the turbine through a heat utilization system bypass passage, and at least a heat utilization system exchanger is provided in the middle of this heat utilization system bypass passage, and a steam control system is installed on the upstream side of this heat utilization system exchanger. The steam control valves are provided with valves, and the number of bypasses for the main steam to be bypassed to the condenser via the heat utilization system bypass path is controlled according to the opening degree of the steam control valves. The main steam flow direction is configured to control the flow direction of main steam introduced into the main steam.

[Embodiments of the invention]

Hereinafter, an embodiment of a nuclear power plant according to the present invention will be described with reference to FIG. 1 and FIG.

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, in which a reactor core 2 is housed in a boiling water type nuclear reactor 1. This reactor core 2 is entirely submerged with reactor water 3.
It is designed to generate steam when heated. Reactor water 3
is forcibly circulated within the reactor 1 by the recirculation pump 4.

As a result, steam is effectively generated, and the furnace heat output (generated steam ff1) is controlled by varying the furnace water flow m. The reactor 1 is connected to a turbine 6 via a main steam pipe 5, and the main steam generated in the reactor 1 is introduced into the turbine 6 to do work, and a generator 7 is directly connected to the turbine 6.
Drive! ilJ′! It's designed to look like this. The condenser 8 of the turbine 6 is connected to the reactor 1 via a condensate pipe 9, and a feed water pump 10 and a feed water heater 11 are respectively installed in the middle of the condensate pipe 9. The condensed water cooled and condensed in is returned to the atom p1 as feed water.

A main steam control valve 12 is interposed in the main steam pipe 5 near the main steam inlet of the turbine 6 to adjust the amount of steam introduced into the turbine 6.

Is there a turbine bypass in the middle of the main steam pipe 5 on the upstream side of the main steam control valve 12? 213 is connected to one end, and the other end is connected to the condenser 8. Turbine bypass pipe 13
A turbine bypass valve 14 is interposed in the middle.

This turbine bypass valve 14 opens when the load decreases significantly, and bypasses the reduced amount of main steam flowing into the steam bin 6 directly to the condenser 8, thereby suppressing a sudden rise in pressure within the reactor 1. .

The main steam pipe 5 is connected to one end of the heat utilization system piping 15. The other end of the heat utilization system piping 15 is connected to the steam control valve 1 midway.
6. After each heat exchanger 17 is interposed, it is connected to the condenser 8 to form a closed loop. The secondary side of the heat exchanger 17 is connected to a heat utilization system A that uses the steam obtained by exchanging heat with the primary side as process steam for industrial or heating purposes.

This heat utilization system A further includes a second heat exchanger (not shown).
It is also possible to create steam or hot water with high utilization by intervening.

Figure 2 shows the main steam control valve 12, the turbine bypass valve 14,
Each control system that controls the opening degree of each steam control valve 16 is shown, and the main steam control valve 12 is controlled by a turbine steam control system 20. Turbine steam control system 20 is pressure control system 2
1 and the frequency control system 22, and output a control signal to the main steam control valve 12,
The main steam inflow m introduced into the turbine 6 is adjusted by controlling the opening degree of the valve. The frequency control system 22 detects the rotation speed T1 of the lightning generator 7 or the rotation speed of the turbine 6,
Rotate this detected rotation number? 11 detects a change in the number of times T by comparing it with a set value To, thereby detects a load fluctuation, and controls the valve 1 of the main steam control valve 12 according to the width of the load fluctuation. be. That is, the frequency control system 22 changes the main steam inflow m at a preset rate in response to fluctuations in the rotational speed of the generator 7, etc., and when the rotational speed increases, the frequency control system 22 changes the main steam inflow m to the turbine 6 when the rotational speed increases. Conversely, when the main steam inflow m is decreased, the main steam inflow is increased. On the other hand, the pressure control system 21 causes a pressure detector 21a installed in the main steam pipe 5 to detect the pressure of the main steam, detects pressure fluctuations from the detected pressure,
The main steam inflow m to the turbine 6 is adjusted at a preset ratio in response to the pressure fluctuation. The pressure control signal output from the pressure control system 21 is also input to the turbine bypass control system 23 that controls the valve 170 degrees of the turbine bypass valve 14, and the pressure in the special reactor 1, where the load has been significantly reduced, suddenly increases. When this occurs, the turbine bypass valve 14 is opened to allow a portion of the main steam to escape to the condenser 8, thereby preventing overpressure within the atom P1. The steam discharged to the condenser 8 is simply cooled and condensed without being utilized for heat, and all the thermal energy of this discharged steam becomes a loss and is finally discarded into seawater.

The steam control valve 16 is controlled by a heat exchanger steam control system 24 which receives a frequency control signal from a frequency control system 22 . The steam WAgfJ valve 16 is always in operation during normal operation of the reactor 1, and a portion of the main steam is always supplied to the heat exchanger 1.
Steam or dry water is generated on the secondary side of the heat exchanger 17, and this steam is used as process steam for effective heat utilization in the heat utilization system A. During normal operation, the sum of the main steam inflow groups is adjusted so that it is always constant. The heat exchanger steam control system 24 receives the frequency control signal output from the frequency control system 22, detects fluctuations in power demand, that is, fluctuations in the load of the generating filter 17, and detects fluctuations in the load fluctuation range. In a case corresponding to so-called governor-free operation with a small width and a fast cycle, the valve opening degree of the steam control valve 16 is controlled to control the amount of main steam distributed to the heat exchanger 17, and the turbine This steam control valve 16 controls the inflow of main steam to
The groove bottom is formed such that the valve opening control direction of the main steam control valve 12 is opposite to the valve opening control direction of the main steam control valve 12. That is, when the main steam control valve 12 is controlled to increase the valve opening, the steam control valve 16 is controlled to decrease the valve opening, and the steam is divided into the turbine 6 and the heat exchanger 17. The sum of the main steam inflows m is always constant, and the atoms fj51
The furnace output (generated steam m) is always kept constant. Therefore, by controlling the opening degree of the steam control valve 16 to control the inflow m of the main steam to be diverted to the heat exchanger 17, the inflow steam to the turbine 6 can be maintained while the reactor output of the reactor 1 is kept constant. By controlling m by 1ilj, the output of the power generation BM 7 can be made to quickly follow the load fluctuation.

The adjustable width of the inflow steam flowing into the turbine 6 and the heat exchanger 17 (the adjustable width depends on the characteristics of the nuclear power plant, but is limited to within a few percent when it corresponds to governor-free operation).

On the other hand, if the fluctuation range of load fluctuation is relatively large and the fluctuation period is long, the pressure control system 21 changes the reactor output of the reactor 1 as in the conventional example, and the output of the generator 7 is adjusted to the load fluctuation. to follow. That is, when such a load fluctuation occurs, the core flow m is changed by controlling the operation of the recirculation pump 4, and the reactor output (generated steam m) is controlled. This changes the pressure inside the reactor 1, so the pressure control system 21
The opening degree of the main steam control valve 12 is appropriately controlled to maintain the inside of the reactor 1 at a predetermined value.

〔Effect of the invention〕

As explained above, the present invention provides a nuclear power plant in which main steam generated in a nuclear reactor is introduced into a turbine through a main steam flow path in which a main steam control valve is installed. The main steam flow path on the upstream side of the valve is communicated with the condenser of the turbine via a heat utilization system bypass passage, and at least a heat utilization system exchanger and a heat utilization system A steam control valve is installed on the upstream side of the system exchanger, and the opening of the steam control valve is controlled to cause the condensate to flow through the heat utilization system bypass path.

The bypass flow of the main steam that is bypassed to the turbine is adjusted appropriately to control the main steam flow port that is introduced into the turbine.

Therefore, according to the present invention, the sum of the steam flows m flowing into the turbine and the heat exchanger of the heat utilization system is always kept constant, so that the blunt is stabilized without affecting the reactor side. can be driven. Furthermore, the steam generated on the secondary side of the heat exchanger of the heat utilization system can be effectively used for industrial purposes as process steam.

In addition, in response to load fluctuations, the main steam control valve, steam control valve,
7. - The generator output is controlled by the pin bypass valve 17iIrfIIIJ, and these valves open and open very quickly, making it possible to achieve control with extremely quick response to load fluctuations. can.

In other words, for small and fast load fluctuations that correspond to governor-free operation, the generator output is made to follow the valve opening control of the main steam control valve and the steam control valve, so it is possible to quickly follow the load fluctuations. be able to. Further, when the load fluctuation is relatively slow and the fluctuation width is relatively large, the furnace output can be controlled by the pressure control system to make the generator output follow the load fluctuation, almost in the same way as in the conventional example.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a nuclear power plant according to the present invention, and FIG. 2 is a main part system diagram showing the main parts of the control system of the embodiment shown in FIG. 1... Nuclear reactor, 2... Reactor core, 3... Reactor water, 4...
・Recirculation pump, 5... Main steam pipe, 6... Turbine, 7... Generator, 8... Condenser, 9... Condensate pipe,
1o... Water supply pump, 11... Water supply heater, 12.
...Main steam control valve, 13...Turbine bypass pipe, 1
4... Turbine bypass valve, 15... Heat utilization system piping, 16... Steam control valve, 17... Heat exchanger, 20...
... Turbine steam control system, 21 ... Pressure control system, 21
a...Pressure detector, 22...Frequency control system, 23.
... Turbine bypass control system, 24... Heat exchanger steam control system, A... Heat utilization system.

Claims (1)

[Claims] In a nuclear power plant in which main steam generated in a nuclear reactor is introduced into a turbine through a main steam flow path in which a main steam control valve is installed, a main steam flow path upstream of the main steam control valve is provided. is connected to the condenser of the turbine through a heat utilization system bypass passage, and at least a heat utilization system exchanger is provided in the middle of this heat utilization system bypass passage, and a steam control system is installed on the upstream side of this heat utilization system exchanger. The bypass flow rate of the main steam to be bypassed to the condenser via the heat utilization system bypass path is appropriately adjusted by controlling the opening of the steam control valve, and the main steam to be introduced into the turbine is A nuclear power plant characterized by controlling the flow rate of steam.