JPS6073397A - Method of operating nuclear power turbine 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] [Field of Application of the Invention] The present invention relates to a method of operating a nuclear turbine plant,
In particular, the present invention relates to a method of operating a nuclear turbine plant suitable for operation in a low load zone.

[Background of the invention]

FIG. 1 shows the system of a known nuclear power turbine plant.

This plant consists of a nuclear reactor 1 that is a steam source, a turbine 2 that converts the thermal energy of the steam into operating energy, a condenser 5 that circulates the turbine exhaust steam, and a feed water heater that warms the condensate and supplies water to the reactor. It consists of pipes connecting the equipment 7 and the above equipment. The steam generated in the nuclear reactor 1 performs work in the turbine 2, and then is led to the condenser 5 where it is condensed into condensate. Feed water heater 7 whose heat source is extracted steam from the condensate drain and turbine extraction line 13
The reactor is heated by water and supplied to the reactor IK.

In such a plant, the reactor feed water temperature changes depending on the plant load, as shown in FIG.

However, when the reactor feed water temperature decreases during low load, the generation of voids in the reactor is suppressed, resulting in a problem in that the necessary amount of steam cannot be obtained.

Furthermore, the system of a known nuclear power turbine plant with a moisture separator and reheater is shown in FIG.

The plant consists of a nuclear reactor 1 which is a steam source, a high pressure turbine 2 and a low pressure turbine 4 which convert the thermal energy of the steam into kinetic energy, and a moisture separation reheating system which reheats the steam output from the high pressure turbine 2 and removes moisture. A condenser 5 that condenses the steam exiting the low-pressure turbine, a low-pressure feedwater heater 6 and a high-pressure feedwater heater 7 that warm the condensate and supply water to the reactor, and piping between the above equipment. . The reactor-generated steam is led to a high-pressure turbine 2 and, after doing work, is dried and reheated in a moisture separator reheater 3 and flows into a low-pressure turbine 4.

The steam that has done work in the low pressure turbine 4 is led to the condenser 5 and becomes condensed water. After being heated in a condensate drain, a low-pressure feedwater heater 6 and a high-pressure feedwater heater 7, it is supplied to the reactor 1. Also,
As the heat source for reheating the moisture separation reheater 3, reactor generated steam (hereinafter referred to as main steam) and high pressure turbine oil steam (hereinafter referred to as high pressure extracted air) are used.Heating steam from both systems is After exchanging heat with the high-pressure turbine exhaust steam in the moisture separation reheater 3, the water is led to the high-pressure feed water heater 7, where it is used again as a heat source and becomes a drain.

In such a plant, the reactor feed water temperature also changes as shown in FIG. 3, so the problem often arises that the required amount of steam cannot be obtained at low loads.

[Purpose of the invention]

An object of the present invention is to provide a nuclear turbine plant operating method that maintains the reactor feed water temperature above a certain value by incorporating high enthalpy steam into the steam supplied to the feed water heater during low load times. be.

[Summary of the invention]

The key point of the present invention is that in order to prevent the reactor feed water temperature from decreasing during low load, when the plant load falls below a predetermined value, the steam supplied to the feed water heater is extracted from the steam on the upstream side of the normally supplied steam. Is there a regulation to incorporate it? It's about doing 1llll. In addition, in a turbine equipped with a moisture separation reheater, if this is introduced, the amount of high-pressure extracted air supplied to the hot 1i1L reheater will be reduced, but since the diversion of high-pressure exhaust air is almost the same, the moisture separation and reheating The enthalpy of the heater outlet drain is relatively reduced. Therefore, at the same time as the above-mentioned intake is carried out, the destination of the outlet drain of the moisture separation reheater, which discharges the steam supplied from the high-pressure extraction gas, is changed from the high-pressure feedwater heater to the low-pressure feedwater heater. The above operations keep the reactor feed water temperature above a certain value. Furthermore, if this switching is performed rapidly, the pressure will drop transiently and the outlet drain of the moisture separation reheater will flush, so the valve switching is performed at a low speed that does not cause this flashing. In addition, if there is a large difference in the time between switching the steam supplied to the high-pressure feedwater heater and switching the destination of the discharge side drain from the moisture separation reheater, pressure fluctuations will occur in the moisture separation reheater, resulting in a pressure drop. In this case, the outlet drain may flush, so the above two switchings are synchronized.

[Embodiment of the Invention] An embodiment of the present invention is shown in FIG. A bleed steam pipe 17 and a supply bleed switching valve 16 are added to the system shown in Fig. 1 to supply high-temperature steam to the feedwater heater 7 during low load, and the switching valve 16 is set so that the plant load is below a predetermined value. I made it open when the

When a plant is controlled using this system, the reactor feed water temperature has the characteristics shown in FIG. 4 with respect to the plant load. That is, in the range A where the switching valve 16 is closed, the steam supplied to the feed water heater 7 is supplied only to the extraction line 13, similar to the conventional characteristic shown in FIG. On the other hand, in range B where the plant load is 0% or less, the switching valve 16 is opened and
Supply high-temperature, high-pressure extraction steam as heating steam. In this case, in order to prevent the feedwater outlet temperature of the feedwater heater 7 from falling below DC, the reactor feedwater outlet temperature is detected and the supply bleed switching valve 16 is opened by the required amount to supply high enthalpy steam to the feedwater heater 7. .

The supply bleed air switching valve 16 is controlled by opening the supply bleed air switching valve 16 until the deviation between the actual reactor feed water temperature and the target temperature DC becomes zero. Further, the supply bleed air switching valve 16 can be an electric valve, but it can also be hydraulically driven for reasons such as a large diameter. An example is shown in FIG. The valve drive mechanism is
An electro-hydraulic converter 19.11 that converts the electrical signal 29 from the control system into a hydraulic signal; a valve-driven hydraulic cylinder 27 that opens and closes according to the hydraulic signal from the oil converter 19; and a valve-driven hydraulic cylinder 27 that feeds back the stroke of the hydraulic cylinder to the control thread 11. It consists of a differential transformer 28. In response to a valve opening signal from the control system, the battery converter 19 supplies oil to the lower part of the hydraulic cylinder 27 and closes the supply steam switching valve 16.
Open money. The valve stroke is fed back to the control system by a differential transformer 28.

Next, another embodiment of the present invention in a moisture separation reheat profiteering plant will be described with reference to FIG. In addition to the conventional system shown in FIG. 2, there is a high-pressure bleed air supply pipe 17, a supply bleed air switching valve 16, and an outlet of the water separation reheater 3 for switching the steam supplied to the high-pressure feed water heater 7 during low load. A drain pipe 18 for guiding drain to the low pressure feed water heater 6 and a low pressure feed water heater artificial drain valve 15 are installed.

As shown in Figure 4, the reactor feed steam temperature remains constant in the low load range of the plant, i.e. in the range A, as before, the high pressure feed water heater supply steam is supplied to the bleed line in Figure 7. 13, and the moisture separation reheater drain 11 is connected to the high pressure feed water heater 7 by opening the high pressure feed water heater artificial drain valve 14.
discharge to.

On the other hand, in range B where the plant load is 0% or less,
In order to prevent the reactor feed water temperature from dropping below Dtll, the reactor feed water temperature is detected and the supply bleed switching valve 1G is opened to supply high enthalpy steam to the high pressure feed water heater 7, and at the same time, the moisture separation reheater In order to change the connection destination of the outlet drain 11 of No. 3, the high pressure feed water heater artificial drain valve 14 is closed and the low pressure feed water heater artificial drain valve 15 is opened.Thereby, the reactor feed water temperature is maintained at DtT.

The above three valves are opened and closed by the mechanism shown in FIG. This machine 17 includes lightning, oil converter 19, actuator 20,
Rack 21, pinion 22, camshaft 23, cam 24, cam lever 25, pylon HP 26, valve drive cylinder 27
, a differential transformer 28.

Incoming signal 2 in actuator opening direction to battery converter 19
When 9 is inserted, the electro-hydraulic converter 19 is connected to the actuator 20.
supplying oil to the boat below. This causes the piston of the actuator 20 to rise and push up the rack 21.

As the rack 21 rises, the pinion 22 rotates counterclockwise, and the camshaft 23 and cam 24 similarly rotate counterclockwise.

The shape of the cam 24 causes the cam lever 25 to move up and down, which moves the pilot valve 26 up and down to supply or discharge oil to the lower part of the valve drive cylinder. This opens and closes the high-pressure feedwater heater inlet drain valve 14. The crab, low-pressure feed water heater artificial drain valve 15, and supply bleed air switching valve 16, which are omitted in FIG. 5, are also opened and closed by a cam on the same camshaft 23. The opening/closing mode of the valve is as shown in FIG. That is, in the range of Fig. 4, the actuator stroke is operated at the 00 point, and the actuator is stroked at the point of the plant load C%.
First, the high-pressure feed water heater artificial drain valve 14 is opened, and the low-pressure feed water heater artificial drain valve 15 is opened. After that, the supply bleed air switching valve can be opened to a safe level.

At this time, in order to keep the amount of air extracted from the high-pressure turbine constant, it is necessary to open the low-pressure feed water heater artificial drain valve 15 to a certain opening (3).
In order to determine the opening degree of Slightly open the artificial drain valve 14.

The opening degree of the supply bleed air switching valve is determined by detecting the reactor feed water temperature. Therefore, as the plant load decreases, the stroke of the actuator 200 increases. This switching should be performed slowly over a predetermined period of time to prevent the outlet drain of the moisture separator and reheater 3 from flashing.

According to this embodiment, since the valves are opened and closed using the same camshaft, the relationship between the opening degrees of the valves is constant as shown in Fig. 9, so there are no accidents due to valve malfunction. .

It is also an injection port that all valve operations are performed electrically. In other words, a heavy oil converter can be connected to each valve to directly open and close the valve drive cylinder. According to this method,
The mechanism can be easily extended to 4".

〔Effect of the invention〕

According to the present invention (1'), even during low load plant operation, the problem that the reactor feed water temperature decreases and the necessary amount of steam cannot be obtained can be completely solved.

[Brief explanation of drawings]

Figure 1 is a system diagram of a known nuclear turbine plant;
The figure is a system diagram of a nuclear turbine plant equipped with a moisture separation reheater, Figure 3 is a characteristic diagram showing the relationship between plant load and feed water temperature in a conventional system, and Figure 4 is a diagram showing the relationship between plant load and feed water temperature in a conventional system. FIG. 5 is a system diagram of a nuclear turbine plant in which the present invention is implemented. FIG. 6 is a diagram showing a switching valve. A system diagram of a nuclear turbine plant equipped with a moisture separation reheater, FIG. 8 is a diagram showing the structure of a switching valve, and FIG. 9 is a diagram showing the opening characteristic of the valve. 1... Nuclear reactor, 2... Turbine, 5... Condenser,
7... Feed water heater, 13... Bleeding line, 16...
・Switching valve, 13 fig. l'l Finish + [111-ta Stro-2 (Su

Claims (1)

[Claims] 1. A nuclear reactor as a steam generation source, a turbine that converts the thermal energy of the steam into kinetic energy, a condenser that condenses the turbine exhaust steam, and a feed water heater that warms territorial water and supplies water to the reactor. A method for operating a nuclear turbine plant, characterized in that the temperature of the reactor feed water is maintained at a set value or higher by incorporating high enthalpy into the heating steam supplied to the feed water heater during low load of the plant. . 2. A method for operating a nuclear power turbine plant in item 1 of the 4'Hr claim, characterized in that, in order to improve plant efficiency, high enthalpy steam taken into the feedwater heater is used as turbine extraction steam. 3, fI'\W [In claim 1, there is further a plurality of feed water heaters in series, a high pressure turbine and a low pressure turbine as turbines, and the high pressure turbine extracted steam is dried and reheated using high enthalpy steam. In a nuclear power turbine plant with a moisture separator reheater, when the plant is under low load, high enthalpy steam is introduced into the feed water heater supply steam on the high pressure side, and at the same time, the outlet drain of the moisture separator reheater is A nuclear turbine plant operating method characterized by maintaining nuclear power feed water temperature above a set value by switching from a high pressure side feed water heater to a low pressure side feed water heater. 4. The turbine plant operation according to claim 3, characterized in that the discharge destination of the moisture separator outlet drain is switched for a set time or longer such that the moisture separator outlet drain does not flash. Method.